WO2001056090A1

WO2001056090A1 - Magnetoresistance effect device and method for manufacturing the same, base for magnetoresistance effect device and method for manufacturing the same, and magnetoresistance effect sensor

Info

Publication number: WO2001056090A1
Application number: PCT/JP2001/000475
Authority: WO
Inventors: Migaku Takahashi; Satoshi Miura; Masakiyo Tsunoda
Original assignee: Sharp Kabushiki Kaisha; Tsukishima Kikai Co., Ltd.
Priority date: 2000-01-28
Filing date: 2001-01-25
Publication date: 2001-08-02

Abstract

A magnetoresistance effect device having a structure of artificial lattice or spin-bulb type, a high MR ratio with as small a quantity of oxygen as possible in a multiplayer structure, and an excellent thermal stability. The magnetoresistance effect device having a structure where alternated nonmagnetic layers and ferromagnetic layers formed on a base or where alternated nonmagnetic layers and ferromagnetic layers formed on a base and a nonferromagnetic layer formed on the uppermost ferromagnetic layer, is characterized in that a buffer member is provided on the base-side surface of the ferromagnetic layer nearest to the base and consists of at least one first element selected from Si, B, C, and Ge and at least one second element selected from Fe, Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf, and Ta.

Description

Specification

Technical field

The present invention relates to a magnetoresistive element, a method for manufacturing the same, a substrate for the magnetoresistive element, a method for manufacturing the same, and a magnetoresistive sensor. More specifically, in a magnetoresistive element made of an artificial lattice type or spin valve type structure, a high MR ratio can be obtained even if the amount of oxygen contained in the structure is reduced as much as possible. And a method of manufacturing the same. Further, the present invention relates to a substrate capable of forming the magnetoresistive element having the above configuration and a method of manufacturing the same. The magnetoresistive element according to the present invention can be used in various magnetic recording and reproducing devices such as a hard disk device, a floppy disk device, and a magnetic tape device. It is suitably used for effect sensors. Background art

With the increase in magnetic recording density, the read head (reproducing head) for reading the signal magnetic field recorded on the medium changes from an inductive magnetic head that uses the time derivative of the change in the magnetic field as the reproduction output to the magnetic field strength. The head is shifting to a magnetoresistive head that uses the read output as the output. Initially, the magnetoresistive effect element used in the magnetoresistive head is a permalloy exhibiting an anisotropic magnetoresistive effect (AMR) in which the electric resistance changes depending on the angle between the direction of current flowing through the element and the direction of magnetization. In recent years, a giant magnetoresistive effect (GMR) exhibiting a larger rate of change in resistance than AMR has been discovered in Fe ZCr multilayers, Co / Cu multilayers, etc. Is expected to be applied to a magnetoresistive element. The structure of such a GMR magnetoresistive effect element is an artificial lattice-type structure composed of a structure in which a ferromagnetic layer is laminated a plurality of times on a surface of a substrate as described above with a nonmagnetic layer (a spacer) interposed therebetween. In addition, a structure in which a ferromagnetic layer is laminated on a surface of a substrate with a non-magnetic layer interposed therebetween, and an antiferromagnetic layer is formed on the surface of the lastly provided ferromagnetic layer The spin-valve type consisting of a body is widely known: In the spin-valve type, the ferromagnetic layer at the position in contact with the antiferromagnetic layer is called a fixed magnetic layer. The ferromagnetic layer at the position in contact is called a free magnetic layer. In either case, GMR is a phenomenon in which the electrical resistance changes according to the relative angle of the magnetization direction between the layers of the ferromagnetic layers constituting the laminated film. When scattering at the interface with the magnetic layer, the interface is caused by a property called spin-dependent scattering, in which the scattering is different depending on the spin direction of the electrons and the magnetization direction of the ferromagnetic layer. A multilayer film utilizing such a phenomenon exhibits high resistance when the magnetization directions generated in the opposing ferromagnetic layers via the non-magnetic layer are antiparallel, When they are arranged in parallel, they exhibit low resistance. In view of this, the present inventors have focused on the influence of impurities present in the film formation atmosphere on the microstructure of each layer, particularly in a multilayer film showing a GMR having a laminated structure of extremely thin layers of several A to several tens A, He has been conducting research and development and has filed patent applications and reports as follows.

(1) By reducing the amount of oxygen contained in the laminated structure to 10 O wtppm or less, the MR ratio is remarkably improved in either the lattice-type or spin-valve magnetoresistive element. It was disclosed (Japanese Patent Application No. 7-193882: MIG010). According to the same publication, as a method of producing a laminated structure having an oxygen amount of 10 O wtppm or less, after the back pressure in the film formation chamber is set at 10- ^y Torr or less, the impurity concentration as a film forming gas is reduced. It is described that a sputter deposition method using Ar that is 10 ppb or less is effective.

(2) as the manufacturing method of increasing the MR ratio in the magnetoresistive element of the artificial lattice type, after the back pressure of the film forming space and 1 0- ⁹ Torr table below, trace oxygen or in the film forming space The back pressure of the film formation space is changed to a pressure higher than 10— ^: 'Torr level by introducing a gas containing water, and Ar gas is further introduced. Disclosed that the method of preparing by the scatter method is effective (International application PCT / JP97 / 1091)

(3) By adjusting the time to evacuate the film formation space after opening to the atmosphere, the cleanliness of the film formation atmosphere is changed by the residual gas mainly containing moisture (Η, Ο),

Reported the microstructure and GMR effect of Cu multilayers. (Miura et al .: The effect of residual gas in the deposition atmosphere on the GMR effect of Co / Cu multilayers, The 22nd Annual Meeting of the Japan Society of Applied Magnetics, 1998.) According to September 20 announced) one same report, the case of using a thermal oxide film with Si (100) single crystal base plate [Si / Si0 ₂ substrate and referred], MR ratio, pre-deposition pressure is 7 X 1 takes a maximum near 0 Torr, further decreases abruptly when before lowering the pressure deposition, 1 0 - ¹ "when the the tendency to become substantially zero was confirmed by Torr table below shows the maxima MR ratio It was confirmed that the root mean square (Rms: root mean square) increased (3 A → 4 A) on the ultra-high vacuum side around the pre-deposition pressure (7 X 10 " ^s Torr) Was done.

(4) The increase in Rms in (3) above is due to the fact that the crystal grains constituting each layer become large, and the unevenness between the central part and the grain boundary part becomes remarkable. The occurrence was evident from cross-sectional TEM observations (S. Miura et al:

Drastic change of giant magnetoresi stance of Co / and u multilayer by decreasing residual impurities in sputtering atmosphere: Journal of Applied Physics, 85, 4463-4465, 1999) 0 Conversely, the experimental results, each layer from the film formation atmosphere The introduction of a small amount of impurities, especially oxygen, into the film has the effect of suppressing the crystal growth of the film and improving the flatness of the lamination interface. From the above-mentioned literature, it can be seen that in order to obtain a magnetoresistive element having a high MR ratio, it is necessary to include an appropriate amount of oxygen in the laminated structure. If the method of forming a stacked film by evacuating once to below 1 Torr and then intentionally introducing oxygen into the space described in (2) above, the film forming space must be high vacuum (10 (3) The above (3) is a method of forming a laminated film by evacuating to a degree of vacuum in the latter half of the order of ^s T ₀ rr) and making good use of oxygen remaining in the space. Both approaches are: By incorporating a small amount of oxygen into the laminated film, miniaturizing the crystal grains that make up the laminated film, and improving the planarization of the laminated interface, a device with a large MR ratio was realized. However, for example, a magnetic head incorporating a magnetoresistive effect element, when mounted on a magnetic recording device, is exposed to a heat generation temperature (150 ° C to 170 ° C) generated by a sense current or the like for a long time. Is in a situation to be done. If the magnetoresistive effect element is exposed to such thermal conditions for a long period of time, oxygen contained in the laminated structure that constitutes the element is thermally affected and starts to move in the laminated structure. Is considered to fluctuate. Specifically, oxygen is unevenly distributed in each layer, or localized at the interface between the layers, or in extreme cases, oxygen is released from the laminated structure to the outside, and the flatness of the interface is deteriorated. Can be considered. However, in a magnetoresistive element manufactured by the methods described in the above four documents, the inclusion of an appropriate amount of oxygen in the laminated structure is an essential condition for realizing a high MR ratio. The problem to be solved is that magnetoresistive elements manufactured by various methods are susceptible to thermal effects and lack long-term reliability.

Therefore, the development of a magnetoresistive element and a method of manufacturing the same, which can realize a high MR ratio without containing oxygen in the laminated structure and also has thermal stability, have been expected. There is also a need for a substrate for a magnetoresistive element and a method of manufacturing the same that simultaneously achieves a high MR ratio and thermal stability without depending on the laminated structure of the magnetoresistive element, so-called artificial lattice type or spin valve type. Had been. Therefore, the present inventor has proposed a method of controlling the initial growth process of the laminated structure, instead of the method of providing an appropriate amount of oxygen in the laminated structure as in the prior art, so that the crystal grains constituting each layer of the laminated film are controlled. By increasing the in-plane grain size of the crystal grains without changing the level of the surface irregularities, the flatness of each layer is improved, and thereby a flat interface is obtained, resulting in a magnetoresistance effect with a high MR ratio. We have been conducting research and development on fabrication methods to realize devices. The present invention relates to a magnetoresistive element having a human lattice type or spin valve type structure. δ

An object of the present invention is to provide a magnetoresistive effect element which achieves a high MR ratio without containing oxygen as much as possible in a laminated structure and has excellent thermal stability, and a method for manufacturing the same.

In addition, the present invention can form an element having a high MR ratio and excellent thermal stability without depending on a laminated structure of the magnetoresistive element, so-called artificial lattice type / spin valve type. A second object is to provide a substrate and a method for producing the same.

Furthermore, a third object of the present invention is to provide a magnetoresistive sensor which is hardly affected by heat when mounted on a magnetic recording device and has excellent long-term reliability. Disclosure of the invention

A magnetoresistive element according to the present invention has a structure in which a ferromagnetic layer is laminated a plurality of times on a substrate with a nonmagnetic layer interposed therebetween, or a ferromagnetic layer is laminated with a nonmagnetic layer interposed therebetween. A magnetoresistive effect element having a structure in which an antiferromagnetic layer is formed on the surface of the ferromagnetic layer provided in the above, wherein the ferromagnetic layer located closest to the substrate in the structure is closer to the substrate side. A buffer member, wherein the buffer member includes one or more first elements selected from Si, B, C, and Ge, and Fe, Ti, Cr, and Mn. , C o, N i, C u, Z r, the magnetic according to _f. present invention is characterized with one or more second elements selected from H f or Ding a, in that they are composed of There are the following two methods for manufacturing a resistance effect element. The first method of manufacturing a magnetoresistive element (referred to as a first element manufacturing method) includes a step of arranging a substrate in a space capable of reducing pressure and reducing a back pressure of the space to a level of 10- ^lu Torr or less. , On the substrate, one or more first-elements selected from Si, B, C or Ge, and Fe, Ti, Cr, Mn, Co, Ni, C forming a deposited layer comprising a buffer member composed of one or more second elements selected from u, Zr, Hi or Ta; and a substrate comprising the substrate and the deposited layer Forming a A structure in which a ferromagnetic layer is laminated a plurality of times with a non-magnetic layer interposed therebetween, or a ferromagnetic layer with a non-magnetic layer interposed therebetween, on the deposition layer forming the surface of the base; Forming a structure in which an antiferromagnetic material layer is formed on the surface of the provided ferromagnetic material layer. The method of manufacturing the second magnetoresistive element (referred to as the second element manufacturing method) includes one or more first or two or more selected from Si, B, C, and Ge in a space where pressure can be reduced. An element and one or more second elements selected from Fe, Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf or Ta forces; and a step of depositing layers of a buffer member arranged base body made provided on the substrate, reducing the pressure of the back pressure of the film-forming space 1 0 one ¹ '' below Torr stand constituted by the surface of the substrate A step of performing a dry etching treatment on the deposited layer to be formed; and a structure in which a ferromagnetic layer is laminated a plurality of times with a non-magnetic layer interposed between the deposited layer after the dry etching treatment, or a non-magnetic layer. Forming a structure in which an antiferromagnetic layer is formed on the surface of the lastly provided ferromagnetic layer, It is characterized in that Bei was. The substrate for a magnetoresistive effect element according to the present invention comprises at least one or two or more first elements selected from Si, B, C, and Ge on the surface layer of the substrate, and Fe, T one, two or more second elements selected from i, Cr, Mn, Co, Ni, Cu, Zr, Hf, and Ta; and a buffer member comprising It is characterized by: A method of manufacturing a substrate for a magnetoresistive effect element according to the present invention includes the steps of: arranging a substrate in a space where pressure can be reduced; and reducing the back pressure of the space to a level of 10- ^lu Torr or less. One or two or more first elements selected from Si, B, C or Ge, and Fe, Ti, Cr, Mn, Co, Ni, Cu, Z producing a buffer member composed of one or two or more second elements selected from r, H} and Ta, and forming a substrate composed of the substrate and the buffer member. It is characterized by doing ... A first magnetoresistive sensor according to the present invention includes a magnetoresistive element having a structure in which a ferromagnetic layer is stacked a plurality of times on a base with a nonmagnetic layer interposed therebetween. A buffer member is provided on the substrate side of the ferromagnetic material layer located near the substrate, wherein the buffer member includes one or more first elements selected from Si, B, C, and Ge; One or more second elements selected from Fe, Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf or Ta. second magnetoresistive sensor according to _c present invention is characterized in that there is on the substrate, laminating the ferromagnetic layers sandwiching a nonmagnetic layer, the surface of the ferromagnetic layer finally provided A magnetoresistive element having a structure on which an antiferromagnetic layer is formed; and a ferromagnetic element located near a substrate in the structure. A buffer member is provided on the base side of the body layer, wherein the buffer member includes one or more first elements selected from Si, B, C, and Ge, and Fe, Ti, C selected from r, Mn, Co, Ni, Cu, Zr, Hf or Ta

And one or more second elements. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic cross-sectional view showing an example of the magnetoresistance effect element according to the present invention. FIG. 2 is a schematic sectional view showing another example of the magnetoresistance effect element according to the present invention.

FIG. 3 is a schematic sectional view showing another example of the magnetoresistance effect element according to the present invention.

FIG. 4 is a schematic sectional view showing another example of the magnetoresistance effect element according to the present invention.

FIG. 5 is a graph showing the relationship between the MR ratio of the magnetoresistive elements manufactured in Example 1 and Comparative Example 1 and the composition ratio of Si contained in the FeSi buffer layer.

FIG. 6 is a graph showing the relationship between the MR ratio of the magnetoresistive elements manufactured in Example 4 and Comparative Example 2 and the pressure in the film forming chamber (in the case where oxygen is introduced, the pressure after introducing oxygen). Ruji

FIG Ί is a graph showing the results of examining the structure surface of the magnetoresistance effect element manufactured in Example 4 and Comparative Example 2 In nuclear force microscope (AFM) _u

FIG. 8 is a schematic diagram showing an example of the magnetoresistive sensor according to the present invention.

FIG. 9 is a schematic diagram showing another example of the magnetoresistive sensor according to the present invention. FIG. 10 is a schematic plan view of a sputtering film forming apparatus used for producing a magnetoresistive element according to the present invention as viewed from above.

(Explanation of code)

1 First load room,

2 Second loading room,

2a, 3a, 4a, 4a, 5a, 6a, 7a, 7a ', 8a Exhaust means, 2b, 3b, 5b, 6b 7b, 8b

3 Pretreatment room,

4 transfer room,

5 First deposition chamber,

6 Second deposition chamber,

7 Third and fourth deposition chambers,

8 Fifth deposition chamber

9 Sixth deposition chamber,

1 0, 1 1 substrate moving means,

100 substrate,

1 0 1 board,

10 2 a buffer member consisting of a sedimentary layer,

1 0 2 b Buffer member consisting of doping layer,

103 ferromagnetic layer,

104 non-magnetic layer,

1 0 5 Artificial lattice type structure,

200 substrate, 2 0 1 board,

2 0 2 a Fa member consisting of a sedimentary layer,

2 0 2 b Buffer member consisting of doping layer,

2 0 3 free magnetic layer,

2 0 4 First ferromagnetic layer,

2 0 5 second ferromagnetic layer,

206 nonmagnetic layer,

2 0 7 fixed magnetic layer,

2 0 8 antiferromagnetic layer,

2 0 9 Spin valve type structure,

2 1 0 protective layer,

8 0 0 8 1 0 Magnetoresistance effect element,

8 0 1 board,

8 0 2 Buffer material,

8 0 3 artificial lattice type structure,

804 membrane

8 0 5 M R electrode,

8 0 6 protective film,

8 20 magnetic drum,

8 2 1 Magnetic recording medium,

9 0 1 magnetoresistive effect element,

9 0 2 Knock-off member,

9 0 3 Spin valve type structure,

9 0 4 Hard film,

9 0 5 M R electrode,

9 1 1 Playback head,

9 1 2 Upper shield that doubles as lower magnetic pole (9 2 4)

9 1 3 9 1 4 Insulation membrane,

9 1 δ Lower shield of playback head, 9 1 6 substrate,

9 2 1 Record head,

9 2 2 Top ball of record head,

9 2 3 Conductor coil,

9 2 4 Lower magnetic pole also serving as upper shield (9 1 2) Best mode for carrying out the invention

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are schematic cross-sectional views showing an example of a magnetoresistive element according to the present invention. FIG. 1 shows a case where an artificial lattice type structure is provided on a buffer member composed of a deposited layer. Reference numeral 2 indicates a case where a spin-valve type structure is provided on a buffer member made of a deposition layer. In FIG. 1, 100 is a substrate, 101 is a substrate, 102 a is a buffer member made of a deposited layer, 103 is a ferromagnetic layer, 104 is a nonmagnetic layer, and 105 Is an artificial lattice type structure. In FIG. 2, reference numeral 200 denotes a substrate, reference numeral 201 denotes a substrate, reference numeral 202a denotes a buffer member composed of a deposited layer, reference numeral 203 denotes a free magnetic layer composed of a ferromagnetic material, and reference numeral 204 denotes a first magnetic layer. Magnetic layer, 205: second ferromagnetic layer, 206: non-magnetic layer, 206: fixed magnetic layer made of ferromagnetic material, 208: antiferromagnetic layer, 20 9 is a spin valve type structure. The magnetoresistive effect element according to the present invention includes a structure 105 in which a ferromagnetic layer 103 is laminated a plurality of times on a base 101 with a nonmagnetic layer 104 interposed therebetween, or a nonmagnetic layer. A structure in which the ferromagnetic layers 203 and 207 are laminated with the interposition of 206 therebetween, and the antiferromagnetic layer 208 is formed on the surface of the lastly provided ferromagnetic layer 207 In the magnetoresistive element provided with a buffer member, a buffer member is provided on the substrate side of the ferromagnetic layers located closest to the substrate among the structural bodies. a, 202 a is provided, wherein the buffer member 102 a, 202 a is one or two or more first elements selected from S i, B, C or Ge, One or more second elements selected from Fe, Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf or Ta; Has been established. That is, the magnetoresistive element according to the present invention has the following two configurations depending on the structure provided on the buffer member. The first configuration is the most basic substrate 100 out of the artificial lattice type structure 105. This is the case where a buffer member 102a is provided on the substrate side of the ferromagnetic layer 103 located in the vicinity (Fig. 1).

The second configuration is a case where a buffer member 202a is provided on the substrate side of the ferromagnetic layer 204 located near the substrate 200 in the spin valve type structure 209 (FIG. 2). is there

. At that time, as the buffer member 102 a, 202 a, one or two or more first elements selected from Si, B, C, or Ge, and Fe, Ti, One or two or more second elements selected from Cr, Mn, Co, Ni, Cu, ZI ", Hf or Ta. In the case of an element having any one of the two structures, by providing the buffer members 102 a and 202 a on the substrate side of the structural bodies 105 and 209, the element formed thereon can be formed. It is possible to increase the in-plane crystal grain size of the lowermost ferromagnetic layers 103 and 204. As a result, the flatness of the stacked interface in the structures 105 and 209 is remarkably improved. As a result, an element having a high MR ratio can be stably obtained, and according to the present invention, an appropriate amount of oxygen is introduced into the structures 105 and 209 as described in the related art. Without doing When high heat is applied to the element during use, oxygen in the structures 105 and 209 starts to move, and the layers 105 and 209 are stacked. As a result, the element according to the present invention can have a high MR ratio and also have excellent thermal stability. Although the description has been given of the case of the deposited layers 1002a and 202a (FIGS. 1 and 2) formed on the surfaces of 01 and 201, other forms may be used. For example, the surface layer of the substrate is provided by doving treatment. An example is a form of a driving layer.

[¾3 and FIG. 4 are schematic cross-sectional views showing another example of the magnetoresistive element according to the present invention. FIG. 3 shows an artificial lattice structure on a buffer member 102 b composed of a doping layer. when provided with a body 1 0 5, 4 buffer member made of a _t the de one ping layer exhibiting, when a buffer member 2 0 2 b on the structure 2 0 9 spin valve type comprising a doped layer Since 102b and 202b constitute the surface layer of the substrates 101 and 201, it is possible to provide the substrates 100 and 200 in which the buffer member and the substrate are integrated. In other words, the buffer members 102 b and 202 b made of the doping layer have a substrate 101 and a substrate 101 caused by the influence of thermal or external force, compared to the buffer members 102 a and 202 a made of the deposited layer. Since peeling off from the substrate 201 can be prevented, the interface between the structural members 105 and 209 laminated thereon has an advantage that its flatness can be maintained for a longer period of time. Further, it is preferable that the buffer members 102 and 202 include at least Fe and Si. When the composition of the buffer member is 2 atomic% or more and 36 atomic% or less and the balance is Fe, an element having an MR ratio more than twice that obtained without Si is preferable. . When the composition of the buffer member is S i of 4 atomic% or more and 26 atomic% or less and the balance is Fe, it is more preferable because an element having an MR ratio exceeding 40% can be obtained stably. As shown in FIG. 1 or FIG. 2, the first element manufacturing method according to the present invention comprises the steps of: forming an artificial lattice type structure 1 on a buffer member 102 a or a buffer member 202 a composed of a deposited layer; In this method, the surface of the buffer member 102 a or the buffer member 202 a is not exposed to the atmosphere at all, and the structure Alternatively, according to the first device manufacturing method, first, a desired back pressure can be obtained in a space of less than 10-1 ^l 'Torr. By preparing the buffer members 102a and 202a in the form of a deposited film on the substrates 101 and 201, the buffer members 102a and 202a containing as little oxygen as possible can be used. Substrates 100 and 200 provided on the plates 101 and 201 can be formed. Then, in a space where the back pressure is less than 10- "" Torr, the artificial lattice structure 105 or the spin valve structure is placed on the buffer member 102a or the buffer member 202a. By manufacturing the body 209, the structures 105 and 209 containing as little oxygen as possible can be formed.Thus, when the first element manufacturing method is used, the structures 105 and 209 are used. In addition to preventing oxygen from being taken into the structure, the structure 1 can be placed on clean buffer materials 102 a and 202 a that have just been manufactured without performing dry etching treatment or the like. In other words, according to the first element manufacturing method, the buffer member 102 a and the structural body 105 can be formed in the same thin film manufacturing apparatus. Since the buffer member 202a and the structure 209 can be manufactured continuously, it is necessary to add a process called dry etching. Ku, clean interface can be obtained stably, it is possible to provide a manufacturing flop opening process.

'A second element manufacturing method according to the present invention employs an artificial lattice type structure on a buffer member 102 a or a buffer member 202 a composed of a deposited layer as shown in FIG. 1 or FIG. A method of providing a structure 105 or a spin-valve type structure 209, in which the surface of the buffer member 102a or buffer member 210a is once exposed to the atmosphere, and then the structure 105 Alternatively, this is a case where the structures 209 are formed by lamination. According to the second element manufacturing method, first, a substrate 1001 provided with buffer members 102a and 202a in the form of deposited films on the substrates 101 and 201 in advance. , 200, and a back pressure of 10— ^lu Torr or lower, and the substrate 100, 200 on the surface, ie, the surface of the buffer members 102, 202 Dry etching is performed on As a result, the outermost surfaces of the buffer members 102a and 202a are cleaned in an atmosphere that is not affected by oxygen as much as possible, and adsorbed substances are removed from the surfaces of the buffer members 102a and 202a. Can be cleaned: then, with its clean surface condition Since the buffer member 1 0 on 2 a, 202 a, in the back pressure 1 0- ¹ "Torr stand following space structure 1 0 5 or prepared child a spin-valve structure 209 of the artificial lattice type Thus, the structures 105 and 209 containing as little oxygen as possible can be formed. Therefore, when the second element manufacturing method is used, the artificial lattice structure 105 or the spin valve structure 20 9 is a device different from the thin film manufacturing device that forms the buffer layers 102 a and 202 a on the desired substrates 101 and 201 in advance. In other words, according to the second element manufacturing method, the thin film manufacturing apparatus for forming the structures 105 and 209 is restricted to the process of forming the buffer members 102 a and 202 a. Can be used exclusively for the formation of the structures 105 and 209, so that a more stable manufacturing process of the structures 105 and 209 can be established and simplified. The substrate for the magnetoresistive effect element according to the present invention is selected from Si, B, C or Ge at least on the surface layer of the substrates 100 and 200. One or more primary elements and one selected from the group consisting of Fe, Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf, and Ta Or two or more second elements, and a buffer member 102, 202 composed of: an artificial lattice type or a buffer member 102, 202 forming a surface layer portion of the base; By forming one of the spin-valve structures 105, 209, the first layer formed in contact with the buffer member 102, 202, that is, the ferromagnetic layer 103, which forms the structure, is formed. And 204 can increase the in-plane crystal grain size, thereby improving the flatness of the lamination interface in the structures 105 and 209. Since the element is remarkably improved, an element having a high MR ratio can be manufactured stably, and when a substrate having this structure is used, oxygen is contained in the structure 105 or the structure 209 as in the conventional case. Therefore, a device with a high MR ratio can be obtained, and the thermal stability of the device can be improved at the same time. As the buffer members 102 and 202 in the above configuration, the deposited layers (Fig. 1, Fig. 2) Alternatively, those having the form of a driving layer (Figs. 3 and 4) are preferably used. For example, in the case of FIG. 1, the substrate 101, the buffer member 102a of the deposited layer, and the substrate 100 made of a force represent the substrate for the magnetoresistive element according to the present invention. Similarly, the base 200 shown in FIG. 2 is a combination of the substrate 201 and the buffer member 202a of the deposited layer, and the base 100 shown in FIG. 3 is a combination of the substrate 101 and the buffer member 1◦2b of the doving layer. The substrate 200 shown in FIG. 4 is a combination of a substrate 201 and a buffer member 202 b of a doping layer. The substrate 101 in the above configuration is formed on the substrate 100 200 In order to maintain the flatness of the thin film, it is necessary to appropriately control the surface flatness, that is, the surface roughness and waviness. a <0. I nm or less and surface waviness of 500 nm or more) can be obtained stably, and a Si (100) single crystal substrate or a Si (100) single crystal substrate with a thermal oxide film, A glass substrate (for example, # 7059 manufactured by Ning) is frequently used. On the other hand, when the magnetoresistive effect element according to the present invention is mounted on a magnetic sensor or a magnetic head, for example, glass, ceramic, a composite thereof, or a different material may be used as the substrate. A non-magnetic film made of a material that has been subjected to a surface coating treatment by a sputtering method, a vapor deposition method, a plating method, or the like is used. In this case, the non-magnetic film provided on the surface of the substrate 101 201 is magnetized at high temperature. It is required to have conductivity, to be mechanical, and to be smooth. In particular, in magnetic head applications, it is preferable that the magnetic head has an appropriate surface hardness enough to withstand friction and wear during head sliding. As a substrate that satisfies these conditions, particularly for practical use in a head, a nonmagnetic film is provided on the surface of an Altic (a sintered body of aluminum oxide and titanium carbide) substrate. Are preferred. As the nonmagnetic film in this case, Cu, Ta, W, Ti, or Cr is desirable.- The method for manufacturing a substrate for a magnetoresistive effect element according to the present invention (claim 10) A step of arranging the substrate in a space that can be decompressed and reducing the back pressure of the space to a level of 10— “Torr or less; at least the surface layer of the substrate is selected from SiBC or Ge One or more first elements and one or two selected from Fe, Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf, or Ta Producing a buffer member composed of the above-described second element and: and forming a base composed of the substrate and the buffer member. Hereinafter, the operation of the buffer member 102a made of the deposited layer of FIG. 1 will be described as an example, using an apparatus different from the apparatus for manufacturing the structure 105 of FIG. According to method of producing the substrate, using a film formation apparatus of the buffer member prepared, producing a buffer member 1 0 2 b in the back pressure 1 0- ¹ "Torr stand in the following space desired substrate 1 0 1 on This makes it possible to form the substrate 100 including the buffer member 102b containing as little oxygen as possible.Therefore, a film forming apparatus for manufacturing a structure is used to form a magnetic resistor on the substrate 100. When dry etching is performed on the substrate 100 before forming the structure 105 serving as an anti-effect element, almost no oxygen is released from the buffer member 102 b, and the buffer member It is possible to provide a substrate 100 that can bring the surface of 102b to an extremely clean state in a short time, that is, by using the method for producing a substrate according to the present invention, The structure 105 can significantly reduce oxygen uptake into the stack from the initial growth stage. In addition, a clean interface can be stably formed, and the structure 105 formed on the base 100 becomes the first layer formed in contact with the buffer member 102 b, That is, by increasing the in-plane crystal grain size of the ferromagnetic layer 103 forming the structure, the flatness of the laminated interface in the structures 105 and 209 is remarkably improved. if higher elements formed by _c the production method obtained by stable substrate, even after the buffer member prepared, carbonochloridate Ffa even member surface is once exposed to the atmosphere, the deposition for the structures prepared In the apparatus, the buffer member 102b having a clean surface can be prepared in a short time whenever necessary, that is, the base according to the present invention has an effect on the fabrication of a structure in a later step. It can be made in advance without giving it, so existing post-processes are effective While using This means that a magnetoresistive element having a higher MR ratio than before can be easily manufactured: The method for manufacturing a substrate according to the present invention also means that a substrate that can be distributed by itself is obtained. Action by substrate manufacturing method-In order to exert the effect, Si, B-. C or Ge force is selected as a buffer member constituting ¾! ¾]. A first element and selected from Fe, Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf or T,-] or two or more second elements It is necessary to provide a buffer material composed ofバッ Buffer in the method of making the book ';

It is preferable to form a deposited layer composed of the buffer member 02 on the substrate 101. However, it is preferable to use various ion etching methods performed under an ultra-high vacuum. It is needless to say that the same action and effect can be expected even if the process is used by changing the surface layer of the substrate 101 to a buffer member 102 b. The resistance effect element is used for various kinds of magnetoresistive effect sensors (also referred to as MR sensors). At that time, the magnetoresistive sensor according to the present invention is not limited to the magnetoresistive effect to be used, but may be any of the anisotropic magnetoresistive effect (AMR) and the giant magnetoresistive effect (GMR). No problem. The magnetoresistive sensor according to the present invention can be used, for example, to detect VTR tape tapes.

Can be used in a wide range of applications, such as MR heads that replace DD inductive magnetic heads

The magnetoresistive effect element according to the large invention has a high MR ratio and excellent stability ', and must be equipped with two elements: high-resolution and long-term reliability. vd can be provided. In the embodiments described later, the case where an element having an artificial lattice type structure is applied to a magnetic head (FIG. 8) for a rotational position detection sensor (a rotary encoder) is shown, and the case where an element having a spin valve type structure is used. Is applied to a playback head for HDD (Fig. 9).

(Artificial lattice type structure)

As the artificial lattice type structure 105 shown in FIG. 1 or FIG. 3, for example, if it is described as a ferromagnetic layer 103 and a nonmagnetic layer 104, CoZCu, Co-Fe / C u, N i — F eZC u, N i-F e / A g, N i — F e — C oZC u, ¥ e / C τ, As the ferromagnetic layer 103, C ο A large MR ratio is easily obtained when the system is used, and a small saturation magnetic field is easily obtained when the Ni system is used. FeZCr has been studied as a transition metal in comparison with a precious metal spacer in understanding its mechanism. Among them, the Co system is preferably used because a high MR ratio, which is the object of the present invention, is easily obtained. The thicknesses of the non-magnetic layer 104 and the ferromagnetic layer 103 are appropriately determined in order to reduce the saturation magnetic field while maintaining a high MR ratio. The thickness of the nonmagnetic layer is 0.5 ηπ! It is preferable that the ferromagnetic layer has a thickness of 0.5 nm to 5 nm. In the artificial lattice type structure 105, the ferromagnetic layer sandwiches the nonmagnetic layer 1◦4. The number of times of lamination of 104 is preferably about 100 to 100 times. By setting the number of laminations in this range, it is possible to suppress the increase of the undulation of the structure.

(Sbin valve type structure) The spin-valve structure 209 shown in FIG. 2 or FIG. 4 has an antiferromagnetic material layer 208 and a fixed magnetic layer 2 composed of a ferromagnetic material layer at a position in contact with the antiferromagnetic material layer 208. And a free magnetic layer 203 composed of a ferromagnetic layer at a position in contact with the fixed magnetic layer 207 and the nonmagnetic layer 206 via the nonmagnetic layer 207. Antiferromagnetic layer 2 0 8 Z Pinned magnetic layer 2 0 7 Z Nonmagnetic layer 2 0 6 Z Free magnetic layer 2 0 3 If expressed as F e M n / N i Fe Z Cu / N i F e, F e M n / N i Fe / A g / N i Fe, F e Mn / Co / C u / N i Fe E Fe Mn / C o N i Fe / C u / NiFe, MnIr / Co / Cu / (Co / NiFe), NiO / NiFe / C / NiFe, NiO / Co / Cu / N i Fe, etc., the _c- spin-valve type provides an MR ratio of about 4% with a small magnetic field of about 80 AZm (lOe) and a non-magnetic layer. Magnetic layer with no hysteresis due to thick magnetic layer Currently, it is the hottest spot because of its curved shape. The thicknesses of the nonmagnetic layer 205, the free magnetic layer 203 composed of a ferromagnetic layer, and the fixed magnetic layer 207 are appropriately determined in order to reduce the saturation magnetic field while maintaining a high MR ratio. Can be The thickness of the nonmagnetic layer 205 is 0.5 nm to 5 nm, and the thickness of the ferromagnetic layers 203 and 207 is

0. δ nm to 5 nm force; The thickness of the antiferromagnetic layer 208 is preferably 1 nm to 10 ° nm. Recently, in order to improve the magnetic field sensitivity of the magnetoresistance effect, the free magnetic layer 203 may be formed of a multilayer film composed of different ferromagnetic layers. For example, a free magnetic layer composed of a layer that increases the MR ratio and a layer that improves the softness of the magnetization reversal is used. 2 and 4 show a case where the free magnetic layer 203 is composed of two layers, a first ferromagnetic layer 204 and a second ferromagnetic layer 205. , 3 layers of free magnetic layer 203 Even with the above-described multilayer film, the operation and effect of the above-described magnetoresistive element including the buffer member according to the present invention do not change. Further, as shown in FIG. 2 or FIG. 4, a protective layer 210 may be provided on the spin-valve type structure 209. The protective layer 210 is mainly composed of the antiferromagnetic layer 20. 8 is provided to prevent oxidation. In the embodiment described later, the case where a Ta film is provided as the protective layer 210 is shown. However, magnetic or electrical influences must be exerted on the structure 209 located below the protective layer 21.0. For example, the protective layer 210 may be made of any material, and its thickness is not limited.

(Oxygen concentration of non-magnetic layer, ferromagnetic layer and antiferromagnetic layer)

The nonmagnetic layer, ferromagnetic layer, and antiferromagnetic layer according to the present invention are formed on the buffer member according to the present invention, but each layer must be prepared under conditions that contain as little oxygen as possible. However, this does not apply to the case where only the antiferromagnetic layer is made of, for example, an oxide such as NiO. Conventionally, when the ultimate degree of vacuum (back pressure) in the film formation chamber is set to 10 to ⁹ Torr or less and an impurity concentration of 10 ppb or less is used to fabricate, each layer contains 100 wtppm or less of oxygen. There is a report that a good MR ratio can be obtained at this time (Japanese Patent Publication No. 7-193882). However, when manufacturing a magnetoresistive effect element having the buffer member according to the present invention, which has both a high MR ratio and excellent thermal stability, it is preferable to manufacture the magnetoresistance effect element under the condition that oxygen is not taken into each layer. Is good. Specifically, the ultimate vacuum (back pressure) of the film forming chamber is preferably in the order of 10- ^lu Torr or less, and the impurity concentration of the Ar gas is preferably 1 ppb or less. It goes without saying that the target material should have as little oxygen content as possible. However, increasing the MR ratio in device having a buffer member according to the present invention, since the first start with conditions backpressure was 1 X 1 0 one ^s Torr or less, 1 0- ^y Torr stand back pressure Even if it is manufactured by the method described above, Considering the difference between the conventional manufacturing conditions obtained to some extent and the manufacturing conditions of the present invention, the oxygen concentration of the nonmagnetic layer, the ferromagnetic layer and the antiferromagnetic layer constituting the device according to the present invention is Compared to the numerical value of 100 wtppm, it is estimated to be about 1Z10-0: LZ100. In other words, the nonmagnetic layer, the ferromagnetic layer, and the antiferromagnetic layer according to the present invention are required to be formed under conditions containing as little oxygen as possible.

(Film forming method and film forming apparatus)

As a method of forming a thin film used for manufacturing a silicide member or a structure constituting the magnetoresistance effect element according to the present invention, for example, any method such as a sputtering method, a vapor deposition method, a CVD method, and a plating method may be used. Although it does not matter, a sputtering method capable of stably producing a thin film having excellent adhesion is suitably used. However, in order to avoid oxygen contained in each layer as much as possible, any type of sputtering method can be used as long as it is manufactured using a sputtering apparatus capable of stably obtaining a back pressure of 10 to ⁹ Torr or less. In order to satisfy this back pressure condition, when introducing an inlet into the chamber, release gas from the following release gas sources, which is the main cause of contaminating the film formation atmosphere, is required. It needs to be reduced.

(1) Outgassing from the surface of the material used for the chamber, the main body, and each component

②External air leak

(3) When using a vacuum pump that uses oil, reverse diffusion of oil into the chamber

不純物 Impurities contained in the process gas In the present invention, the magnetoresistive effect element was manufactured using a multi-chamber type sbutter device as shown in FIG. The film forming apparatus is an ultrahigh vacuum pair disclosed in Japanese Patent Application Laid-Open No. H10-2898745. Response Multi sputtering apparatus (Hitachi Zosen Ltd., model HIMS- XO 0 5) in _c Figure 1 0 is, 1 the first load chamber, the two first - second load chamber which is arranged above the mouth one de chamber , 3 is a pretreatment chamber, 4 is a transfer chamber, 5 is a first film formation chamber, 6 is a second film formation chamber, 7 is a third and fourth film formation chamber, 8 is a fifth film formation chamber, 10 and 1 1 is the substrate moving means _{c and} 2a, 3a, 4a, 4a ', 5a, 6a, 7a, 7a' and 8a are oil-free exhaust means for reducing the pressure in each chamber It is. Here, the exhaust means 4 a and 4 a ′ are disposed below the transfer chamber 4 (on the back side of the drawing). Further, 2b, 3b, 5b, 6b, 7b and 8b represent gate valves provided between the respective chambers _t . Each of the above film forming chambers has a sputter-up type structure: A force sword (not shown) on which a target (not shown) is placed is placed below each chamber, and a substrate on which a thin film is to be deposited is located above the target and at a position facing the target surface.

(Not shown). In addition, the space between the target and the substrate is provided with a shutter (not shown), and a mechanism is provided for moving the shirt to deposit a thin film on the substrate only for an appropriate time. . In particular, the third and fourth film forming chambers 7 each have a shield plate (not shown) also having a function of preventing deposition at a position blocking between the respective film forming chambers, and a third film forming chamber and a fourth film forming chamber. Means for moving the substrate between and

(Not shown). In the apparatus shown in FIG. 10, the inner walls of all the chambers 1 to 9 are EL-processed. In particular, each of the deposition chambers 5 to 9 has a feature that a back pressure of the order of ^{10 to 12} Torr can be realized. and are. transfer chamber 4, it is possible to maintain the back pressure in 1 0 ¹ 'Torr stand, since also comprises moving means 1 1 of the group member, which is contained in each layer and the interface of the structure This is a very suitable device for fabricating devices that minimize oxygen. Further, in each of the chambers 1 to 9 constituting the apparatus of FIG. 10, a process gas introduction system (not shown) in which the inner wall surface is subjected to the CRP treatment is arranged.

In the embodiment described later, for example, in the case of the artificial lattice type, the buffer layer is formed in the second film forming chamber 6. In the third and fourth film forming chambers 7, a nonmagnetic layer and a ferromagnetic layer were formed.

In the third and fourth film forming chambers 7, a non-magnetic layer and a ferromagnetic layer are alternately laminated on the surface of the substrate as appropriate by opening and closing the shutter and moving the substrate between the film forming chambers. be able to. By adjusting the number of movements of the substrate, the number of laminations of the structure is controlled. When the substrate is moved by opening the gate valve between the transfer chamber 4 and one of the film formation chambers, a gate that separates the transfer chamber 4 from another film formation chamber in order to avoid contamination of the substrate surface. It is preferable that all the valves be closed.In addition, the generation of electric discharge in the film formation chamber occurs after the substrate is transported into the film formation chamber and the gate valve that spatially partitions the film formation chamber from the transfer chamber 4 is closed. It is preferable to use a process in which the transfer chamber 4 is prevented from being contaminated. In the apparatus shown in FIG. 10, for example, Ar gas is used as a process gas in one chamber 15 and sputtering is performed. When the flow of Ar gas is stopped after the film is formed, the chamber 15 is provided with an exhaust means 5a capable of instantaneously reducing the internal space to a level of 10 Torr. Then, after the chamber 15 is set at the 10- ^ft Torr level, the gate valve 5 b provided between the transfer chamber 4 and the chamber 15 at the back pressure of the 10- ^ll 'Torr level is operated. be opened, the exhaust ability to maintain sufficient 1 ^{0-] u} Torr stand vacuum degree in the transfer chamber 4, the exhaust means 4 a transfer chamber 4, 4 a 'has. Therefore, if the apparatus shown in FIG. 10 is used, the influence of the process gas in the chamber used in the previous step hardly affects the chamber used in the next step.

(EL processing)

Aluminum (A 1), which emits a small amount of gas, is used as the base material, and the newly formed surface is cut off from the atmosphere when the A 1 surface is applied, so that water and impurities in the atmosphere, which are the source of released gas, are taken into the processed surface EX processing and EL processing are widely known as techniques for avoiding this. As a method of shutting off the atmosphere, a high-purity (A r + O:) The method of processing while injecting gas is EX processing [H. Ishimaru; J. Vac. Sci. Technol., A2, 1170 (1984) ZM. Miyamoto et. Al .; J. Vac. Sci. Technol., A4, 2515 (1986)] and EL processing is a method of processing while spraying alcohol on the processing surface in the atmosphere.

[Suemitsu et. Al .; J. Vac. Sci. Technol., A5, 37 (1987)] _{u In} the apparatus of FIG. 10 used in the present invention, the inner wall of all chambers 1 to 8 EL processing technology was applied.

(CRP processing)

CRP processing means that stainless steel (SUS), which emits a small amount of gas, is used as a base material, and its surface is electrolytically polished (ECB) to smooth the surface. A technique for forming a passivation and reducing the amount of emitted gas [T. Ohmi et. Al .; J. Electrochem. So, 140, 1691 (1993)].

In the apparatus of FIG. 10 used in the present invention, this CRP treatment technology was applied to a process gas introduction system.

(Ir gas impurities and their concentrations used in the process)

The gas used in the process of the present invention is a high-purity Ar which shows an impurity concentration of 1 ppb or less at a use point. As the impurities in high purity A r gas, eg, H ₂ 〇, 〇 _{_{CO H 2, NC X H ,,}} H, 0, CO , and the like. In particular, impurities that affect the amount of oxygen taken into the film are estimated to be H ₂₀ , 〇CO 0, and CO. Therefore, the above impurity concentration is a numerical value expressed by the sum of H ₂ 〇, CO 0, and CO contained in the Ar gas used for film formation.

(Clean-Jung processing by high frequency sputtering)

As a cleaning process using a high frequency sputtering method, for example, there is a method of applying an AC voltage from an RF (radio frequency, 1.56 MHz) power supply to a substrate placed in a dischargeable gas pressure space. . The feature of this method is that it can be applied even when the substrate is not conductive. According to the present invention, the surface of the silicide member is cleaned only when a thin film forming an artificial lattice type spin valve type structure is formed on a substrate on which the silicide member is manufactured by another apparatus. In other words, if the silicide member and the structure were continuously manufactured under the same pressure in the same apparatus and the surface of the silicide member was not exposed to the atmosphere, the above-mentioned cleaning process was not used. In order to compensate for the cleanliness inside the chamber in an actual mass production machine, even if the silicide member and the structure are formed in the same equipment, the surface of the manufactured silicide member is cleaned. After that, it goes without saying that a structure may be appropriately formed thereon.

(Impurities and their concentrations in Fe targets and Si chips)

In the examples described later, the Fe target and the Si chip were used when forming the buffer layer composed of the Fe film or the FeSi film.

As the Fe target, Fe having a purity of 99.99 wt% or more was used. Examples of the impurities include Ni, Si, Mg, AI, Mn, Cu, Cr, C, 0, and N. In particular, since impurities that affect the amount of oxygen taken into the film are estimated to be O, the impurity concentration of the Fe target in the present invention is included in the target used when forming the buffer layer. Shows oxygen In the example, a target having an oxygen content of 20 w tp pm was used.When the Fe Si buffer layer was formed, the purity on the Fe target was not less than 99.9999 wt%. The Si chip was mounted thereon to form a thin film having a desired composition ratio.

(Cu target impurities and their concentrations)

In the examples described later, the Cu target used when forming the non-magnetic layer is used as the Cu target. As impurities using Cu having a purity of 99.9999 wt% or more, for example, Ag, U, c, h, C, 0, N and the like can be mentioned. In particular, impurities that affect the amount of oxygen taken into the film are presumed to be ◦. Therefore, the impurity concentration of the Cu target in the present invention may be different from that in the target used for forming the nonmagnetic layer. Indicates the oxygen content. In the example, a target having an oxygen content of less than 1 wtppm was used.

(Co target impurities and their concentrations)

In Examples described later, Co having a purity of 99.9 wt% or more was used as a Co target used in forming the ferromagnetic layer. The impurities include, for example, Ni, Fe, Al, Si, C, 0, and N. In particular, impurities that affect the amount of oxygen taken into the film are estimated to be O. . Therefore, the impurity concentration of the Co target in the present invention indicates the oxygen contained in the target used for forming the ferromagnetic metal layer. In the examples, a target having an oxygen content of less than 1 Owtppm was used.

(Impurity of NiFe target and its concentration)

In an example described later, a Ni Fe target having a purity of 99.9 wt% or more and having a composition of Ni—21.5 wt% Fe is used as a Ni Fe target used in forming a ferromagnetic layer. One was used. Examples of impurities in this target include Si, Cu, AI, A, and N. In particular, impurities that affect the amount of oxygen taken into the film are presumed to be ◦. Therefore, the impurity concentration of the NiFe target in the present invention refers to the oxygen content in the target used for forming the ferromagnetic metal layer. However, a target of 90 wtppm was used.

(MnIr target impurities and their concentrations)

In the examples described later, when forming the antiferromagnetic layer, an MnIr target and an Ir chip mounted thereon were used.

For the MnIr target, Mn-17 at% I with a purity of 99.9 wt% or more A composition having the composition of r was used. In the example, a target having an oxygen a content of 64 wtppm was used.

In order to adjust the film composition, an Ir chip having a purity of 99.9 w% or more was placed on the MnIr target having the above composition to form a thin film having a desired composition ratio. did

(Surface temperature of substrate)

The surface temperature of the substrate when forming the buffer layer, the nonmagnetic layer, the ferromagnetic layer, and the antiferromagnetic layer does not depend on the material of each layer constituting the magnetoresistive element according to the present invention. It is one of the film formation factors that affect the roughness of the film surface. For example, when forming an ultra-thin film of a low melting point metal on a glass substrate, it is known that when the substrate temperature is high, an island-like film tends to be formed. It is. Since the present invention aims to form a thin film having extremely high flatness, the surface temperature of the substrate was maintained at about 20 ° C. by water cooling the back surface of the substrate during film formation.

(Surface roughness R)

The surface roughness in the present invention is defined as a measuring instrument evaluated using the average center line roughness Ra when observing the surface of a human lattice type or spin valve type structure with an atomic force microscope (AFM). Used SFA300 manufactured by Seiko Electronic Industries. From the AFM image obtained after correcting the tilt of the measurement sample, Ra was calculated in the range of S = (500 nm) using the following equation.

[Equation 1]

R a = S " ¹ If I z (x, y) — zuidxdy

[Equation 2]

Where S is the area of the range used for the calculation, and z (x, y) is the average height of the structure surface at position (X, y); (Crystal in-plane particle size L)

The in-plane particle size L of the crystal in the present invention is an average value of the particle size in the in-plane direction of the crystal particles constituting the surface of the artificial lattice type or spin valve type structure. A FM). However, from the result of observing the cross section of the structure using a transmission electron microscope (TEM), the crystal grain size of the second and subsequent layers was substantially the same as that of the first layer. Therefore, it was considered that the average value L of the crystal grains constituting the surface of the structure in the in-plane direction can be evaluated as the numerical value of the crystal grain size of the first layer. Here, the first layer of the structure in the present invention means the ferromagnetic layers 103 and 203 provided in contact with the buffer members 102 and 202. Example

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)

In this example, when fabricating a magnetoresistive element having the buffer layer 102 a shown in FIG. 1 and the artificial lattice type structure 105, an Fe Si film was used as the buffer layer 102 a. The film was manufactured by changing the composition ratio of Si contained in this film in the range of 0 to 40 atomic%, and then a structure 105 was formed thereon. Deposition of each layer is performed in a deposition chamber to not more than 1 XL 0- ¹⁰ Torr back pressure, manufactured by the method of Supattari ring a predetermined data one rodents preparative high purity A r gas. At this time, the thickness of the buffer layer 102 a was fixed at 7.5 nm, and the structure 105 was a non-magnetic layer 103 composed of a Co film and a nonmagnetic layer composed of a Cu film. A layer obtained by laminating body layers 104 alternately 50 times was used. In other words, the magnetoresistive effect element (FIG. 1) manufactured in this example has a substrate 101 / buffer Layer 10 2 a (FeSi film, film thickness 7.5 nm) / (ferromagnetic layer 10 3 (Co film, film thickness l nm) Z non-magnetic layer 104 (Cu film , 1 nm)] r, „. In this example, a Si (100) single crystal substrate with a thermal oxide film on the surface was used as the substrate 101, The substrate temperature was controlled by at least cooling the substrate holder with water. A film forming apparatus for manufacturing the magnetoresistive element having the above-described configuration is disclosed in Japanese Patent Application Laid-Open No. 10-289845. An ultra-high vacuum compatible multi-sputtering apparatus (Hitachi Zosen, model HI MS—X05) was used, and Fig. 10 is a schematic plan view of the film forming apparatus as viewed from above. The first load chamber, 2 is the second load chamber located above the first load chamber, 3 is the pretreatment chamber, 4 is the transfer chamber, 5 is the first film formation chamber, 6 is the second film formation chamber, 7 is the third and fourth film forming chambers, 8 is the fifth film forming chamber, 10 and 1 Reference numeral 1 denotes a means for moving the substrate, and reference numerals 2a, 3a, 4a, 4a ', 5a, 6a, 7a, 7a', and 8a denote exhaust means for reducing the pressure in each chamber. And the exhaust means 4 a and 4 a ′ are arranged below the transfer chamber 4 (on the back side of the paper). Further, 2 b, 3 b, 5 b, 6 b, 7 b, and 8 b are provided between the chambers. In addition, the film forming apparatus shown in Fig. 10 has a process gas supply system (not shown) in each film forming chamber, and the impurity concentration of the Ar gas at its use point is 1 (ppb). The following supply means were used: The thin films constituting each layer were prepared in separate film forming chambers.Specifically, the buffer layer 1 2 was formed in the second film forming chamber 6, and the third and fourth films were formed. A ferromagnetic layer 103 and a nonmagnetic layer 104 were formed in the film chamber. The substrate 101 prepared in the air was maintained so that the back pressure gradually decreased. 、 First mouth Chamber 1 → passed in the order of the second load chamber 2 pretreatment chamber 3 → transportable Okushitsu 4 were introduced into a predetermined film forming chamber, whereby the back pressure of the transfer chamber 4 is maintained 1 0 ¹¹ Torr stand Note that, in this example, the cleaning process on the substrate surface in the pretreatment chamber 3 was not performed. Table 1 shows the film forming conditions when manufacturing the magnetoresistance effect element according to this example.

"table 1"

Item setting value

-Deposition method Parallel plate type sputtering method

-Process gas A r

• Impurity concentration in _Ar gas 1 (ppb) or less

-Back pressure of each deposition chamber P _B 10- ^lu (T orr) units or less

Controlling the temperature of the substrate holder

(Second deposition chamber)

Nouffer layer 102 a FeSi film (film thickness 7.5 nm)

-Target Fe (purity 4N)

+ S i chip '(purity 6 N)

• Process gas pressure 2 (mT or r)

-Deposition rate 2 (A / sec)

(Third deposition chamber)

Ferromagnetic layer 103 C o film (1 nm thick)

• Target Co (purity 3N)

■ Process gas pressure 2 (mT or r)

-Film formation speed 2 (AZ sec)

(Fourth deposition chamber)

Ferromagnetic layer 104 Cu film (1 nm thick)

• Target Cu (6N purity)

• Process gas pressure 2 (mT or r)

-Deposition rate 2 (A / sec)

In the following, a step-by-step description of the method of manufacturing the magnetoresistive element of the present example will be given. (Ml) After introducing a substrate 101 of Si (100) single crystal provided with a thermal oxide film on the surface thereof into the first load chamber 1 constituting the apparatus of FIG. The internal space was evacuated from atmospheric pressure to a pressure of 1 X 10-Torr or less using an exhaust means (not shown).

(2) Using the transfer means 10 to the second load chamber 2 in which the substrate disposed inside the first load chamber 1 is evacuated to a pressure of X 10 Torr or less in advance by the exhaust means 2a. _C moved from the first mouth room 1

(M 3) The transfer means 11 transfers the substrate placed inside the second load chamber 2 to the pretreatment chamber 3 in which the back pressure has been previously reduced to a pressure of 1 X 1 O HTorr or less by the exhaust means 3 a. It was moved using.

(M 4) The transfer of the substrate from the pretreatment chamber 3 to the second film formation chamber 6 or the third and fourth film formation chambers 7 was performed using a transfer means (not shown) built in the transfer chamber 4. In each of the film forming chambers 6 and 7, the back pressure of the internal space was previously maintained at a pressure of 1 × 10— ^lu Torr or less. Further, the back pressure of the transfer chamber 4 is set to 10 nTorr or less, and even when the built-in transfer means is operating, the transfer means does not increase to a pressure exceeding the level of 10 Torr (Japanese Patent Application No. 10-1990). _C using the transfer robot disclosed in Japanese Patent Publication No.

(Mδ) A FeSi film (7.5 nm) was formed as a buffer layer 102a on a substrate 1 • 1 to obtain a substrate 100 according to this example. The procedure is shown in the following (M5-1) to (M5-4).

(Μδ-1) Open the gate valve 3b, take out the substrate from the pretreatment chamber 3 by the transfer means built in the transfer chamber 4, close 3b, open 6b, and go to the second deposition chamber 6. Moved. Then, the gate valve 6b was closed. Even when the substrate was installed, the degree of vacuum in the second film forming chamber 6 was maintained at a pressure of 10 ^lu- Torr or less.

(M5-2) Next, an ultra-high-purity Ar gas was introduced into the deposition chamber 6 until the process gas pressure under the deposition conditions (Table 1) was reached.

(Mδ-3) A predetermined power was applied to the force source to sputter the Fe target on which a predetermined amount of the Si chip was mounted. First, after performing pre-sputtering for a certain time, a shutter covering the substrate surface was opened for a predetermined time to form a 7.5 nm thick FeSi film 102 a on the substrate 101. The thickness of the F e S i film was controlled by closing the shutter after a predetermined time. (Μδ−4) Next, after the power was turned off and the discharge was terminated, the supply of the Ar gas was stopped, and the internal space of the second film formation chamber 6 was evacuated to a pressure of 10-Torr or less.

(M6) Next, on the FeSi film (buffer layer) 102a forming the surface of the substrate 100, a ferromagnetic layer 103 composed of a Co film (thickness 1 nm) and Cu are formed. the non-magnetic layer 1 04 comprising a film (thickness 1 nm) were stacked 5 0 times alternately,. _u indicating the procedure of the following (M 6- 1) ~ (M 6- 8)

(M6-1) After forming the FeSi film 102, the gate valve 6b was opened, the substrate was taken out of the second film forming chamber 6 by the transfer means built in the transfer chamber 4, and 6b was closed. Thereafter, 7b was opened, moved to the third and fourth film forming chambers 7, and placed at a position above the Co target, and then the gate valve 6b was closed. Even in the state where the substrate was set, the vacuum of the film forming chamber 7 was maintained at a pressure of 10 ^lu- Torr or less.

(M6-2) Next, an ultra-high-purity Ar gas was introduced into the film forming chamber 7 until the process gas pressure under the film forming conditions (Table 1) was reached.

(M6-3) Pre-sputtering was first performed for a predetermined time by applying a predetermined power to the two power sources and sputtering the Co target and the Cu target together.

(M6-4) Thereafter, the shirt provided in the space between the Co target and the substrate is opened for a predetermined time to form a 1 nm thick Co film 1 on the FeSi film 102a. 0 3 was formed. The thickness of the Co film was controlled by closing the shutter after a lapse of a predetermined time.

(M6-5) The substrate on which the Co film 103 has been deposited is transferred to the C o target using a means (not shown) for moving the substrate between the third film formation chamber and the fourth film formation chamber. It was moved from the sky position to the sky position of the Cu target.

(M6-6) Thereafter, the shirt provided in the space between the Cu target and the substrate is opened for a predetermined period of time, so that a film having a thickness of 1 ^! 1 is formed on the Co film 103. 104 was formed. The thickness of the Cu film was controlled by closing the shutter after a lapse of a predetermined time.

(M6-7) The substrate on which the Cu film 104 has been deposited is placed above the Cu target using a means (not shown) for moving the substrate between the third film forming chamber and the fourth film forming chamber. From position C o The target was moved to the sky.

(M6-8) Thereafter, the above step (M6-4) to step (M6-7) are repeated 49 times, so that the ferromagnetic layer 103 is not formed on the buffer layer 102a. An artificial lattice type structure 105 in which the magnetic layers 1 to 4 were repeatedly laminated 50 times was produced.

(M7) Finally, the substrate on which the structure 105 has been formed is moved in the order of the film formation chamber 7 → the pretreatment chamber 3—the second port / the first chamber 2—the first port / the first chamber 1 Then, the produced magnetic resistance effect element was taken out of the manufacturing apparatus. In the following, of the magnetoresistive elements fabricated in this example, the sample provided with the Fe Si buffer layer is referred to as Ma (F e Si), and the sample provided with the Fe buffer layer not containing Si. Is called M a (F e).

(Comparative Example 1)

In this example, a magnetoresistive element having a configuration in which the buffer layer 102a was removed from the layer configuration shown in FIG. 1 was manufactured. In other respects, the following _u was the same as in Example 1, it referred to the sample prepared in this example M Monument and (no). FIG. 5 shows the magnetoresistance (MR ratio) of the magnetoresistive elements fabricated in Example 1 and Comparative Example 1 and the composition ratio of Si (atomic% and at%) contained in the FeSi cuffer layer. It is a graph showing the relationship with (notation). Here, the composition ratio of S in the buffer layer is a value measured by X-ray Fluorescence Spectroscopy (XRF). The MR ratio of the device is a value measured by a DC four-terminal method by applying a current in the air at room temperature at room temperature, applying a magnetic field in a direction perpendicular to the current. At that time, the MR ratio was measured by variably controlling the value of the magnetic field within the range of 20 kOe on the soil.In Fig. 5, 〇 indicates sample Ma (F e S i), and ◎ indicates sample M ft. (F e), and the △ mark indicates the sample M _tt (none). From FIG. 5, the following points become clear.

(a1) When the device is manufactured in a deposition chamber with a back pressure of 10 ^lu- Torr or less, In the case of the sample Μ (none), which has the conventional layer configuration without the core layer 102 a, the MR ratio is very low at about 2%, which is a numerical value.

(a2) By providing the Fe film as the buffer layer 102a between the substrate and the structure, the MR ratio slightly increases to about 5%.

(a3) The MR ratio is significantly increased by including Si in the buffer layer 102a made of the Fe film. Specifically, the Si composition ratio in the buffer layer is set to 2 atomic% or more. By setting the content to 36 atomic% or less, an element having an MR ratio more than twice that of the element having the Fe film buffer layer can be formed. In particular, the Si composition ratio is at least 4 at. /. If the value is below, a device with a high MR ratio exceeding 40% can be obtained stably.

(Example 2)

In this example, a magnetoresistive element using a FeGe film, a FeC film, or a FeB film for the buffer layer 102a instead of the FeSi film used in Example 1 was manufactured. . At that time, the composition ratio of each film was as shown in Table 2. Other points were the same as in Example 1. Table 2 shows the MR ratio of devices with a buffer layer consisting of these three types of films. For comparison, Table 2 also shows the case where the buffer layer is the Fe film and the case where the buffer layer is the Fe Si film.

"Table 2"

Film name Composition ratio MR ratio (%)

F e Ge e Fe — 10 at% Ge 47.5

F e C F e-1 2at% C 40.8

F e B F e— 1 2 at% B 3 7.4

F e S i F e— 7at% S i 4 9.0

F e F e δ. 0 From Table 2, it was found that a magnetoresistive element having a large MR ratio can be manufactured even when the FeGe film, the FeC film, or the FeB film is used for the buffer layer instead of the FeSi film. Table 2 shows the results when one element consisting of 51, Ge, C or B was added to the six films, but the same effect was obtained when two or more of these elements were simultaneously added to the Fe film. -It was confirmed that the effect was obtained. .

(Example 3)

In this example, a TiSi film, a CrSi film, a MnSi film, a CoSi film, a NiSi film, and a CuSi film were used instead of the FeSi film used in the first embodiment. A magnetoresistive element using the Si film, the ZrSi film, the HfSi film, or the TaSi film as the buffer layer 102a was manufactured. At that time, the composition ratio of each film was as shown in Table 3. Other points were the same as in Example 1. Table 3 shows the MR ratio of devices with a buffer layer consisting of these nine types of films. For comparison, Table 3 also shows the case where the buffer layer is an Fe film and the case where the buffer layer is an Fe Si film. ':

"Table 3"

Film name Composition ratio MR ratio (%)

T i S i T i ― 7at% S 2 8.0

C r S i C r 1 7at% S 30 3

Mn S i M n-7 at% S 2 2 5

C o S i C o— 7 at% S 1 4 0

N i S i N i — 7 at% S 2 2 0

C u S i C u— 7at% S 1 5 8

ZrSiZr-7at% S2 1 2

H f S i H f ― 7at% S 1 9 0 T a S i T a 7at% S i 2 8.5

F e S i F e 7 at% S i 4 9.0

F e Fe 5.0 From Table 3, it can be seen from Table 3 that the TiSi film, the CrSi film, the MnSi film, the CoSi film, the NiSi film, and the C It was revealed that the effect of increasing the MR ratio was obtained even when the uSi film, the ZrSi film, the HίSi film, or the TaSi film was used for the buffer layer. Table 3 also shows the results when one element consisting of Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf or Ta was added to the Si film. Even if two or more of these elements are added to the Si film at the same time, or Fe is added to these elements, the same action and effect can be expected by appropriately adjusting the content. Needless to say, the above-mentioned other elements may be appropriately added to the buffer layer for the purpose of improving effects other than the MR increase, that is, improving thermal stability, corrosion resistance, mechanical workability, and the like.

(Example 4)

In this example, when the magnetoresistive effect element of FIG. 1, that is, the element composed of the buffer layer 102a and the artificial lattice type structure 105 is manufactured by the sputtering method, both (the buffer layer and the artificial lattice type structure ) with the case of forming by using only the reduced pressure after a r gas deposition chamber to 1 ◦- ^lu Torr table following a predetermined degree of vacuum, the buffer layer is a deposition chamber 1 X 1 0 one ^{1 u} Torr vacuum degree until it formed by using only the reduced pressure after a r gas, after the structure of the artificial lattice type vacuum film deposition chamber to 1 0- ^lu Torr stand vacuum, oxygen _(0:) deposition chamber by introducing a gas the pressure of 1 X 1 ^0-; introducing a r gas was changed to 'constant pressure of Torr~ 1 X 1 0- ⁶ Torr, and a case of forming with (a r + O mixed gas Comparative study _{= At} this time, a Fe Si film (7 at% Si, the balance Fe) was used as the buffer layer 102a, and the other points were the same as in Example 1.

The device fabricated under the former condition is called sample (F e S i), and the device fabricated under the latter condition is called sample My (F e S i). (Comparative Example 2)

In this example, a magnetoresistance effect element having a configuration in which the buffer layer 102 was removed from the layer configuration shown in FIG. 1 was manufactured in the same manner as in Example 4. In this example, an artificial lattice type structure was formed. A device formed using only Ar gas after depressurizing the inside of the film chamber to a predetermined degree of vacuum of 10-'Torr or less is referred to as a sample M (none). -On the other hand, after the artificial lattice structure decompresses the inside of the film formation chamber to 10- "Torr vacuum, oxygen (O) gas is introduced and the pressure in the film formation chamber is set to 1 X 10- ^y Torr. introducing a r gas was changed to a constant pressure of ~ 1 X 1 0- ⁶ Torr, referred to as (a r + O-) elements made form using a mixed gas sample Myuganma (no). FIG. Fig. 6 shows the relationship between the magnetoresistance (MR ratio) of the magnetoresistive elements fabricated in Example 4 and Comparative Example 2 and the pressure in the film formation chamber (or pressure after oxygen introduction if oxygen was introduced).

The MR ratio is a value measured by the same method as in Example 1. In FIG. 6, the symbols 〇 and reference are the samples of Example 4, and the symbol 〇 indicates that oxygen was not introduced [M / 5 (F e S i)]. The symbol 場合 indicates that oxygen was introduced. (F e S i)]. In addition, Δ and ▲ are the samples of Comparative Example 2, and Δ indicates [M β (no)] when oxygen was not introduced, and Δ indicates [My (none)] when oxygen was introduced. Figure 6 reveals the following points.

(b 1) The sample of Comparative Example 2 having the conventional layer configuration without the buffer layer 102 a was prepared when the pressure in the film forming chamber, that is, the back pressure was set to 1 × 10— ^ft Torr or less (marked with △). However, the MR ratio remains as low as about 2-3%.

(b 2) However, even with the sample of Comparative Example 2, it is possible to form an element having a large MR ratio by introducing oxygen gas before manufacturing the structure and changing the pressure in the film formation chamber (marked with ▲). Becomes In particular, it was found that the MR ratio had a maximum value when the pressure after oxygen introduction was 5 X 10- ^s Torr. (b 3) On the other hand, in the sample of Example 4 having a layer structure provided with the buffer layer 1.02a of the FeSi film, the back pressure in the film formation chamber was 1 × 10 Torr or less. (Marked with 〇) High MR ratio exceeding 40% can be obtained stably

(b 4) the samples of Example 4 and by introducing oxygen gas is changed to a constant pressure in the range of pressure in the deposition chamber from 3 X 1 0- ¹¹ Ding orr of 1 X 1 0- ⁶ Torr be fabricated As the pressure increased, the MR ratio of the sample showed a minimum value at 3 X 10 ^s Torr and a maximum value at 1 X 10 ^-7 Torr. Fig. 7 is a graph showing the result of examining the surface of the structure of the magnetoresistive element fabricated in Example 4 and Comparative Example 2 with an atomic force microscope (AFM). (If oxygen is added, the pressure after introducing oxygen), and the vertical axis represents the average center line roughness Ra and the in-plane crystal grain size L. In FIG. 7, the symbols 〇 and Hata are the samples of Example 4, and the symbol 合 indicates the case where oxygen was not introduced [M / 3 (F e S i)], and the symbol 場合 indicates the case where oxygen was introduced [Μγ (F e S i)]. In addition, Δ and ▲ are samples of Comparative Example 2, and Δ indicates [M β (no)] when oxygen was not introduced, and Δ indicates [My (none)] when oxygen was introduced. From Figure 7, the following points became clear.

(b 5) The average center line roughness Ra is 45 A in the ^{10 -1]} 10 Torr range, regardless of the presence or absence of the buffer layer, but decreases with increasing pressure. 10 0 ^s 1 It is about 2 a in the 0- ⁷ Torr table.

(b 6) The tendency of the in-plane crystal grain size to decrease with increasing pressure regardless of the presence or absence of the buffer layer is the same as the average centerline roughness Ra. However, there is a great difference in the numerical value of the in-plane crystal grain size when the structure is manufactured on a 10 10 -Torr level where oxygen is not contained as much as possible. That is, the sample [M / 3 (F e S i)] of Example 4 having the buffer layer was 50% or more in comparison with the sample [Μ ^ '(none)] of Comparative Example 2 having no buffer layer. Was also found to have a large in-plane crystal grain size.

(b 7) Increasing tendency of in-plane crystal grain size in the sample of Example 4 described in (b 6) above Was confirmed at a pressure of 1 ^× 10— ^s Torr or less. The in-plane crystal grain size of the sample of Example 4 manufactured at a pressure of 1 ^× 10— ^s Torr was the same as that of the sample of Comparative Example 2. It was also found that the maximum value of the crystal grain size, that is, the numerical value when fabricated on the order of 10—n to 10— ^ Torr, was exceeded. From the above results, the sample of Example 4 having the buffer layer was a structure By using a 10- to 10- ^lu Torr unit containing as little oxygen as possible, the in-plane crystal grain size can be significantly increased compared to the sample of Comparative Example 2 without a buffer layer, At this time, since there is almost no difference in the average center line roughness Ra depending on the presence or absence of the buffer layer, this increase in the in-plane crystal grain size leads to the flattening of the structure surface and the flattening of the structure interface. As a result, as shown in the above (b3), the sample of Example 4 provided with the buffer layer 102 a 1 0 high MR ratio in the ^lu Torr stand is considered to have been obtained - the other hand, the maximum of the MR ratio of 1 0- ⁸ ~ 1 0 ⁷ Torr, an appropriate amount of oxygen is containing organic in structure, average roughness with R a is small, the surface crystal particle diameter is also smaller, resulting in and the "interface structures are interpreted as caused by the action that has been flattened, further increasing the pressure 1 ^0-: ~ 1 0 — It is presumed that the oxidation of the structure in the ⁶ Torr sample progressed too much and the MR ratio decreased rapidly. Therefore, by providing the buffer layer according to the present invention, the magnetoresistance effect element including the artificial lattice structure can realize a high MR ratio without containing oxygen in the structure as much as possible. The indicated MR ratio is a value obtained by dividing the MR ratio of each sample prepared in Example 4 and Comparative Example 2 after heat treatment at 200 ° C in vacuum by the MR ratio before heat treatment _t. Here, the sample M β ′ (F e S i) includes the F e S i buffer layer 102 a and forms the structure 105 without introducing oxygen (pressure P = 1 × 10− ^lu Torr sample), sample Μγ '(F e S i) has a F e S i In this case, the structure 105 was formed (pressure P = 1 X 10— ^T Torr sample), and the sample M '(none) is the sample My (FeS i) force. The layer with the layer 102 a removed (pressure P = 1 X 10— '. Torr sample).

"Table 4"

Sample name Preparation condition MR ratio (%)

, "Introduction of oxygen

M β '(F e S i) Yes No 0.85-0.80 0

My '(F e S i) Yes Yes 0.63-0.37 7

M β '(none) <0.1 From Table 4, the following points became clear.

(c 1) The sample M (no) having no buffer layer 102 a according to the present invention had a MR ratio smaller than 1 Z 10 before heating by heat treatment at 200 ° C.

(c 2) The sample M / 3 ′ (F e S i) including the buffer layer 102 a according to the present invention and producing the structure 105 without introducing oxygen has a decrease in MR ratio of 15 to It can be reduced to about 20%.

(c 3) Although the buffer layer 102 a according to the present invention is provided, the sample My ′ (F e S i) prepared by introducing oxygen to form the structure 105 has an MR ratio reduced by about 40%. However, this reduction was about twice that of the sample M / 3 '(F e S i). From the above results, in order for the device after fabrication to have both a high MR ratio and excellent thermal stability, it is necessary to provide the buffer layer 102a according to the present invention and to provide the structure 10 in an atmosphere containing as little oxygen as possible. It turns out that it is necessary to make 5.

(Example 5)

In this example, after preparing a substrate 100 having a buffer layer 102a provided on a substrate 101, the substrate 100 was once exposed to the atmosphere, and then an artificial lattice type structure 105 was formed thereon. Is described. In this example, the following steps (ml) to (m5) were provided between the step (M5) and the step (M6) in Example 1.

(m 1) A substrate 100 having a buffer layer 102 formed of a FeSi film formed on a substrate 101 is transferred to the second film forming chamber 6 → the pretreatment chamber 3 → the second load chamber 2 → the The substrate 100 was moved in the order of the bite chamber 1, and the substrate 100 was taken out of the manufacturing apparatus. That is, the buffer layer 102a forming the surface of the substrate 100 was exposed to the air. _: ;

(m 2) Thereafter, the substrate 100 exposed to the atmosphere was re-introduced into the first loading chamber 1 constituting the apparatus shown in FIG. 10, and the internal space of the first opening chamber 1 was changed from atmospheric pressure to 1 X until 1 0- ⁷ Torr or less pressure under using the evacuation means (not shown) and vacuum

(m 3) of substrate〗 0 0 disposed within the first loading chamber 1, previously 1 X 1 0- ⁹ Torr to a two-neck one-de chamber 2 which had been evacuated to a pressure by the exhaust means 2 a It was moved from the first load chamber 1 using the transfer means 10.

(m4) The substrate 100 disposed inside the second inlet chamber 2 is transferred to the pretreatment chamber 3 in which the back pressure P has been previously reduced to a pressure of 1 X 10 Torr or less by the exhaust means 3a. It was moved using the transfer means 11. Thereafter, the surface of the substrate, that is, the surface of the buffer layer was dry-cleaned by inductively-coupled plasma generated under predetermined conditions using ultrahigh-purity Ar gas. This dry cleaning was performed using Ar gas having an impurity concentration of 1 ppb or less, a process gas pressure of 1 OmTorr, and at least cooling the substrate holder with water.

(m5) The substrate 100 after the dry cleaning was moved to the third and fourth film forming chambers 7 by using the transfer means built in the transfer chamber 4. The magnetoresistive effect element manufactured by adding the above-described steps, that is, the element in which the structure 105 is laminated and formed after the surface of the buffer layer 102a is once exposed to the atmosphere, has a buffer layer of 102 It was confirmed that it had a high MR ratio exceeding 40%, similar to the sample of Example 1 in which the surface of a was laminated with the structure ₁₀₅ without exposing the surface to the atmosphere.This result suggests the following: are doing

(d 1) The F e ^Si film formed in the deposition chamber with the back pressure of less than 10 ^lu- Torr The substrate 100 provided with the buffer layer 102a can be subjected to dry cleaning before the structure 105 is provided thereon, with or without exposure to the air on the surface of the buffer layer 102a. A device with a high MR ratio can be formed regardless of

(d2) Only the base 100 having the buffer layer 102a is prepared in advance using a device different from the device that forms the structure 105, and the structure 105 is formed as necessary. A desired device can be manufactured by introducing the device into a device to be formed. As described above, the substrate 100 provided with the buffer layer 102 a according to the present invention on the substrate 101 can distribute itself. and sales it proved possible to. Moreover, if even with the film forming chamber in which an existing device structure for making it possible backpressure to 1 0- ^ll 'below Torr stand, the present invention A substrate 100 having such a buffer layer 102a can be used. This means that the magnetoresistive element according to the present invention having both a high MR ratio and excellent thermal stability can be produced on an existing production line without making new capital investment.

(Example 6)

In this example, a magnetoresistive element having the configuration shown in FIG. 2 was manufactured using a spin-valve type structure 209 instead of the artificial lattice type structure 105. An antiferromagnetic layer 208 is laminated on the layer 207, and all layers usually called a top-spin valve type, that is, a buffer layer 202a, a structure 209, and a protective layer 210 are provided. After depressurizing the film-forming chamber to a degree of vacuum of the order of 10 to 10 Torr, argon (Ar) gas was introduced, and sputtering was performed using only Ar gas.

The spin-valve magnetoresistive element manufactured in this example has a substrate 201 / buffer layer 202a (FeSi film, film thickness 7.5 nm) Z first ferromagnetic layer 204 (N i Fe film, film thickness 3 nm) / Second ferromagnetic layer 205 (Co film, film thickness 1 nm) Z nonmagnetic layer 206 (Cu film, film thickness 2. 5 nm) Non-fixed magnetic layer 207 (J ^ film 膜厚 film thickness! M) / Antiferromagnetic layer 208 (MnIr film, film thickness 5 nm) / Protective layer 210 (Ta film) And a film thickness of 5 nm). At this time, a 7.5 nm-thick FeSi film was used as the buffer layer 202a, and the composition ratio of Si contained in this film was 7 atomic% (at%). Further, in the above laminated structure, the first ferromagnetic layer 204 and the second ferromagnetic layer 205 constitute the free magnetic layer 203. The other points are the same as in the first embodiment. did. The film forming apparatus used for manufacturing the magnetoresistive element having the above-described configuration is a multi-sputter apparatus for ultra-high vacuum shown in FIG. The thin films constituting each layer were prepared in separate film forming chambers. Specifically, the first film forming chamber 5 uses a NiFe film, the second film forming chamber 6 uses a FeSi film, and the third and fourth film forming chambers use a Co film and a Cu film. An MnIr film was formed in the fifth film forming chamber 8, and a Ta film was formed in the sixth film forming chamber 9. Table 5 shows film forming conditions for manufacturing the magnetoresistive film according to the present example.

"Table 5"

Item setting value

-Deposition method Parallel plate type sputtering method

B'Rosesgas A r

-Impurity concentration in Ar gas 1 (ppb) or less

• Back pressure of each deposition chamber PB ¹⁰ " ¹⁰ (T orr) units or less

.Temperature control of substrate holder Water cooling at least the substrate holder

(Second deposition chamber)

Buffer layer 202 a FeSi film (film thickness 7.5 nm)

• Target Fe (purity 4 N)

+ Si chip (purity 6 N)

• Process gas pressure 2 (mTorr)

(First deposition chamber) First ferromagnetic layer 204 NiFe film (thickness 3 nm)

• Target 78.5 wt% Ni-Fe (purity 4 N)

• Process gas pressure 0.75 (mT or r)

(Third deposition chamber)

Second ferromagnetic layer 205 Co film (film thickness 1 nm)

• Target Co (purity 3 N)

• Process gas pressure 0.6 (mTorr)

(Fourth deposition chamber)

Nonmagnetic layer 206 Cu film (2.5 nm thickness)

• Target Cu (purity 6 N)

-Process gas pressure 0.6 (mTorr)

(Third deposition chamber)

Fixed magnetic layer 207 Co film (film thickness 2 nm)

• Target Co (purity 3 N)

• Process gas pressure 0.6 (mT or r)

(Fifth film forming room)

Antiferromagnetic layer 208 Mn Ir film (5 nm thick)

• Target Mn-17 at% Ir (purity 3 N)

+ Ir chip (purity 4 N)

• Process gas pressure 20 (mT or r)

(Sixth deposition chamber)

Protective layer 2 10 Ta film (film thickness 5 nm)

• Target Ta (purity 4 N)

• Process gas pressure 1 (mTorr)

Hereinafter, a method of manufacturing the magnetoresistive effect element of this example will be described step by step. The number in parentheses indicates the procedure.

(S 1) After introducing a substrate 201 made of a Si (100) single crystal substrate provided with a thermal oxide film on the surface thereof into the first load chamber 1 constituting the apparatus of FIG. 1 internal space The using exhaust means (not shown) from atmospheric pressure to a pressure of less than 1 X 1 0- ⁷ Torr vacuo

†:,.

The (S 2) a substrate disposed in the interior of the first load chamber 1, a second load chamber 2 which had been evacuated to advance 1 X 1 0_ ^y Torr or less pressure by the exhaust means 2 a, the conveying means 1 0 Moved from the first load room 1

(S3) The transfer means 11 transfers the substrate disposed inside the second load chamber 2 to the pretreatment chamber 3 in which the back pressure has been reduced to a pressure of 1 X 10 HTorr or less in advance by the exhaust means 3a. It was moved using.

(S4) The transfer of the substrate from the pretreatment chamber 3 to each of the film forming chambers 5 to 8 was performed by using a transfer means (not shown) built in the transfer chamber 4. The back pressure of the internal space was previously maintained at a pressure of 1 X 10— ^lu Torr or ^less.The back pressure of the transfer chamber 4 was set at 10— ^ Torr or less, and vacuum was maintained even when the built-in transfer means was operating. A transfer means whose transfer degree does not rise to a pressure exceeding the 10- ' ^u Torr level (a transfer robot compatible with ultra-high vacuum disclosed in Japanese Patent Application No. 10-266666) was used.

(S5) A FeSi film (7.δ nm) was formed as a buffer layer 202 on the substrate 201 to form a substrate 200. The procedure is shown in the following (S5-1) to (S5-4).

(S 5-1) Open gate valve 3 b, take out substrate from pretreatment chamber 3 by the transfer means built in transfer chamber 4, close 3 b, open 6 b, and move to film formation chamber 6 Let me know. Thereafter, the gate valve 6b was closed. Even when the substrate was installed, the degree of vacuum in the film forming chamber 6 was maintained at a pressure of 1 × 10— ^lu Torr or less.

(S5-2) Ultrahigh-purity Ar gas was introduced into the deposition chamber 6 until the process gas pressure under the deposition conditions (Table 5) was reached.

(S 5-3) force after the predetermined F e target Bok the sputtered _e first fixed time Buresupatta that the applied power is placed a predetermined amount of S i chip Sword, the shutter covering the substrate surface Was opened for a predetermined time to form a 7.5 nm thick FeSi film 202 on the substrate 201. The thickness of the FeSi film was controlled by closing the shirt after a predetermined time.

(S δ - 4) After finishing dropping discharge power, to stop the supply of A r gas was evacuated internal space of the film forming chamber 6 to ¹ X 1 0- 1 ^u Torr pressure below .. (S 6) Next, a Ni Fe film (3 nm) was formed as the first ferromagnetic layer 204 on the Fe Si film (buffer layer) 102 forming the surface of the substrate 200. The procedure is shown in the following (S6-1) to (S6-4).

(S6-1) After forming the FeSi film, open the gate valve 6b, take out the substrate from the film forming chamber 6 by the transfer means stored in the transfer chamber 4, close the 6b, 5b was opened and moved to the film forming chamber 5. Then, the gate valve 5b was closed. Even when the substrate was installed, the degree of vacuum in the film formation chamber 5 was maintained at a pressure of 1 × 10— ^lu Torr or less.

(S 6-2) Ultra-high-purity Ar gas was introduced into the deposition chamber 5 until the process gas pressure under the deposition conditions (Table 5) was reached.

(S6-3) A predetermined power was applied to the cathode to sputter the NiFe target. First, after a predetermined time of batter sputtering, a NiFe film having a thickness of 3 was formed on the FeSi film by opening a shutter covering the substrate surface for a predetermined time. The thickness of the NiFe film was controlled by closing the shutter after a predetermined time.

(S6-4) After the power was turned off to terminate the discharge, the supply of the A1 gas was stopped, and the internal space of the first film forming chamber 5 was evacuated to a pressure of 1 X 10- ^lu Torr or less.

(S 7) Next, a Co film (1 nm) is formed as a second ferromagnetic layer 205 on the N i Fe film (first ferromagnetic layer) 204, and a non-magnetic layer is formed thereon. A Cu film (2.5 nm) was formed as 206, and a Co film (2 nm) was formed thereon as the fixed magnetic layer 207. The procedure is shown in the following (S7-1) to (S7-4).

(S7-1) After forming the NiFe film 204, the gate valve 5b is opened, the substrate is taken out of the film forming chamber 5 by the transfer means built in the transfer chamber 4, and 5b is closed. b was opened and moved to the film formation chamber 7. Thereafter, the gate valve 7b was closed. Even in the state where the substrate was set, the degree of vacuum in the film forming chamber 7 was maintained at a pressure of 1 × 10 −Torr or less.

(S 7-2) Ultra-high-purity Ar gas was introduced into the deposition chamber 7 until the process gas pressure under the deposition conditions (Table 5) was reached.

(S 7-3-1) A predetermined power was applied to the two force sources to sputter the Co target and the Cu target. First, after breathing for a certain period of time, the shutter covering the substrate surface is opened for a predetermined time, so that the thickness on the NiFe film 204 is increased. The thickness of the lCo film (the second ferromagnetic layer) 205 having a thickness of l nm was controlled by closing the shutter after a lapse of a predetermined time.

(S7-3-2) After the substrate on which the Co film (second ferromagnetic layer) 205 has been formed is moved to the Cu target side by the transport means built in the film forming chamber 7, By opening the shutter covering the substrate surface for a predetermined time, a 2.5 nm thick Cu film (nonmagnetic layer) 206 was formed on the Co film 205. The thickness of the Cu film was controlled by closing the shutter after a predetermined time.

(S7-3-3-3) After the substrate on which the Cu film (non-magnetic layer) 206 has been formed is moved again to the Co target side by the transporting means built in the film forming chamber 7, the substrate is Covering the surface A 2 nm thick Co film is formed on the Cu film 206 by opening the shutter for a predetermined time.

(Fixed magnetic layer) 207 was formed. The thickness of the Co film was controlled by closing the shirt after a predetermined time.

(S7-4) After the power was turned off to terminate the discharge, the supply of the _Ar gas was stopped, and the internal space of the film forming chamber 7 was evacuated to a pressure of ^{1 × 10—ltJ} Torr or less.

(S 8) Next, an MnIr film (5 nm) was formed as an antiferromagnetic layer 208 on the Co film (fixed magnetic layer) 207. The procedure is shown in the following (S8-1) to (S8-5).

(S8-1) Open the gate valve 7b, take out the substrate from the film formation chamber 7 by the transfer means built in the transfer chamber 4, close 7b, open 8b, and move to the film formation chamber 8. I let it. Thereafter, the gate valve 8b was closed. Even when the substrate was set, the degree of vacuum in the film forming chamber 8 was maintained at a pressure of 1 × 10— ^lu Torr or less.

(S8-2) Next, an ultra-high-purity Ar gas was introduced into the film forming chamber 8 until the process gas pressure under the film forming conditions (Table 5) was reached.

(S8-3) A predetermined power was applied to the cathode to sputter the MnIr target. First, after performing pre-sputtering for a certain period of time, the shutter covering the substrate surface is opened for a predetermined time to form a \ 511 Ir film 208 with a thickness of 511! 11 on the Co film (fixed magnetic layer) 207 The thickness of the formed MnIr film was controlled by closing a shutter after a lapse of a predetermined time.

(S8-4) Next, after the power is turned off and the discharge is terminated, the supply of Ar gas is stopped. Then, the internal space of the film forming chamber 8 was evacuated to a pressure of 1 X 10— ^lu Torr or less. _C (S 9) Next, a protective layer 2 1 was formed on the Mn_Ir film (antiferromagnetic layer) 208. A Ta film (5 nm) was formed as 0. The procedure is shown in the following (S9-1) to (S9-4)

(S9-1) Open the gate valve 8b, take out the substrate from the film forming chamber 8 by the transfer means built in the transfer chamber 4, close 8b, open 9b, and move to the film formation chamber 9. I let it. Thereafter, the gate valve 9b was closed. Even in the state where the substrate was installed, the degree of vacuum in the film forming chamber 9 was maintained at a pressure of 1 × 10— ^lu Torr or less.

(S 9-2) Next, an ultra-high purity Ar gas was introduced into the film forming chamber 9 until the process gas pressure under the film forming conditions (Table 5) was reached.

(S9-3) A predetermined power was applied to the cathode to sputter the Ta target. First, after performing pre-sputtering for a certain time, a shutter covering the substrate surface was opened for a predetermined time to form a 5-nm-thick Ta film on the substrate. The thickness of the Ta film was controlled by closing the shutter after a predetermined time.

(S9-4) Next, after the power was turned off to terminate the discharge, the supply of the Ar gas was stopped, and the internal space of the film forming chamber 9 was evacuated to a pressure of ¹ × 10-1 QTorr or less.

(S10) Finally, the substrate on which the Ta film (protective layer) 210 has been formed is transferred to the deposition chamber 9—pretreatment chamber 3 → second opening chamber 2 → first loading chamber 1 by moving in this order, _upsilon hereinafter taken out from the magnetoresistive element through the manufacturing apparatus having a laminated structure 209 according to the present embodiment, the magnetoresistance effect element manufactured in the present example sample S monument (F e S i) Call.

(Comparative Example 3)

In this example, in making the free magnetic layer 203 having a layer structure shown in FIG. 2, first, oxygen (Omicron,) after changing the introduced gas pressure Ρ to 1 X 1 0- ⁷ Torr, the A r gas Then, a free magnetic layer 203 was formed by sputtering using a mixed gas of (〇: + A r). In other words, the free magnetic layer 203 formed by introducing oxygen in this example is composed of a Ni Fe film (first ferromagnetic layer) 204 and a Co film (second ferromagnetic layer). it is a layer _Θ The other points were the same as in Example 6. A magnetoresistive element having the layer configuration shown in FIG. 2 was fabricated. In the following, the magnetoresistive element fabricated in this example was referred to as a sample S (F e S i). Call

(Comparative Example 4)

In this example, a magnetoresistive element having a configuration using an Fe film instead of the FeSi film as the buffer layer 202 a having the layer configuration shown in FIG. 2 was manufactured. Other points were the same as in Example 6. Hereinafter, the magnetoresistive element manufactured in this example is referred to as a sample S (F e).

(Comparative Example 5)

In this example, a magnetoresistive element having a configuration in which the buffer layer 202a was removed from the layer configuration shown in FIG. 2 was manufactured. The other points were the same as in Example 6. Hereinafter, the magnetoresistive element manufactured in this example is referred to as a sample S (none). Table 6 shows the MR ratio before and after heat treatment of each sample prepared in Example 6 and Comparative Examples 3 to 5, respectively. The value of “Before heat treatment” is the MR ratio after film formation, and the value of “After heat treatment” is the MR ratio after heat treatment (heating in vacuum at 200 ° C) divided by the MR ratio before heat treatment. Value. Here, the sample S a (F e S i) includes the F e S i buffer layer 202 a, and forms the structure 209 without introducing oxygen (pressure P == 1 X 10— ^lu Torr sample) and sample S β (F e S i) provided with a F e S i buffer layer 202 a and subjected to oxygen introduction to form a structure 209 (pressure P = 1 X 10— ^; Torr sample), sample S layer (F e) has a Fe buffer layer 202 a and has a structure 209 formed without introducing oxygen (pressure P = 1 X 1 0—1 ⁽⁾ Torr sample), sample S "(none) is sample S a (F e S i) force, F e S i No buffer layer 2 ◦ 2a removed (pressure P = 1 X 1 0 one ^1. Torr sample), meaning _c "Table 6"

Sample name Preparation condition MR ratio (%)

/ Fa layer Oxygen introduction Before ripening After heat treatment

S a (F e S i) 4nt

Available 13-17 0.92-0.83

S β (F e S i) Yes Yes 15 ~ 20 0.65 ~ 0.53

S a (F e) Yes 2-3 <0.1

Table 1 shows that the following points are evident from Table 6: _c

(el) The sample S (no) without the buffer layer 202a has a low MR ratio of 1 to 2% before heat treatment, and the MR ratio after heat treatment is almost eliminated.

(e 2) The sample S α (F e) with the Fe buffer layer 202a has an MR ratio before heat treatment of about 2 to 3% and is slightly larger than the sample S α (none), The MR ratio almost disappears.

(e 3) Sample Sa (F e S i) provided with buffer layer 202 a according to the present invention has a high MR ratio of 13 to 17% before heat treatment, and an MR ratio after heat treatment. Can be reduced to within 20%.

(e 4) Sample S (F e Si) formed by introducing oxygen has a high MR ratio of 15 to 20% before heat treatment, but the MR ratio after heat treatment is reduced by 30% or more. I do. From the above results, in order for the magnetoresistive element to have both a high MR ratio and excellent thermal stability, it is necessary to provide the buffer layer 202a according to the present invention and to use the spin valve type structure It was determined that it was necessary to manufacture the product in an atmosphere where it was not contained.

(Example 7)

In this example, a magnetoresistive element having the artificial lattice type structure 105 described in the first embodiment is used, and a magnetic sensor for a rotational position detection sensor (rotary encoder), which is one of the magnetoresistive sensors, is used. The case where a head is manufactured will be described. FIG. 8 is a diagram showing an example of a case where the magnetoresistive element having the artificial lattice type structure according to the present invention is applied to a magnetic head for a rotational position detection sensor (a single encoder). . (a) is a perspective view showing an arrangement example of a magnetoresistive element constituting a magnetic head with respect to a magnetic drum, and (b) is a cross-sectional view taken along the line AA ′ in (a). , 800 and 8100 are magnetoresistive elements constituting a magnetic head, 800 is a substrate, 802 is a buffer member, 803 is an artificial lattice type structure, and 804 is c. Reference numeral 805 denotes an MR electrode, reference numeral 806 denotes a protective film, reference numeral 820 denotes a magnetic drum, and reference numeral 821 denotes a magnetic recording medium. The magnetic recording medium 821, which is provided on the peripheral surface of the cylindrical magnetic drum 82, has multiple poles so that a leakage magnetic field is generated parallel to the moving direction (the direction of arrow B) according to the position reading accuracy. It is magnetized. The magnetoresistive effect elements 800 and 810 are arranged at a distance of, for example, about 100 μm from the magnetic recording medium 82 1. The magnetic head shown in Fig. 8 is composed of two or four magnetoresistive elements 800 and 810 opposed to a multipolar magnetized magnetic recording medium 821, and the surface magnetic field distribution is represented by a sine wave. FIG. 8 shows a case in which two elements are detected. In FIG. 8, other components of the magnetic head are omitted in order to describe the magnetoresistance effect elements 800 and 8100 functioning as a leakage magnetic field detection unit in detail. Other components (not shown) include a lead wire take-out unit for taking out an electronic signal from the leakage magnetic field detection unit, a lead wire, and a means for introducing current to the leakage magnetic field detection unit. The magnetoresistive elements 800 and 810 have a substantially rectangular shape, and the outer circumferential surface of the magnetic drum 820 moves to detect a leakage magnetic field of the multipolar magnetized magnetic recording medium 821. The direction (the direction of arrow B) is set as the short side, and the direction perpendicular to the short side is set as the long side. That is, the plurality of magnetoresistive elements are arranged around the magnetic drum 82. A stripe pattern arranged in a space on the surface so as to form a stripe pattern is manufactured by, for example, etching to a width of several tens of meters and a length of several mm. For example, a width of one magnetoresistive element 800 When a magnetic field is applied in the (short side) direction, the resistance of the element changes so as to take a local maximum value near the inversion of the magnetic field depending on the magnitude. In other words, the magnitude of the leakage magnetic field applied to the element 800 changes with a constant period due to the rotational movement of the magnetic drum 82. If this change is regarded as a voltage change, a sinusoidal signal is obtained. By using this signal, the rotation of the magnetic drum 820 can be controlled. As the rotation speed of the magnetic drum 820 increases, the magnetoresistive element 800 needs to detect the leakage magnetic field with higher sensitivity. The simplest solution is to increase the MR ratio of the element itself, and since the element is placed near the high-speed rotating body, the element is in a condition that is easily affected by heat. Therefore, an element having excellent heat resistance was expected. The magnetoresistive effect element provided with the buffer member according to the present invention achieves a higher MR ratio with a structure manufactured without containing oxygen as much as possible, so that the structure can be protected from thermal effects over a long period of time. The flatness of the formed interface is maintained, and the temporal change of the MR ratio can be suppressed. Therefore, the magnetic head for a rotary encoder to which the element according to the present invention is applied has higher sensitivity and longer-term reliability than the conventional one.

(Example 8)

In this example, a magnetoresistive element having the spin-valve type structure 209 described in Example 6 was used, and a spin-valve type GMR reproducing head, which is one of the magnetoresistive sensors, and A recording / reproducing separation type magnetic head combined with an inductive recording head was fabricated. FIG. 9 shows a magnetoresistive element having a spin-valve structure according to the present invention, FIG. 4 is a diagram showing an example of a case where the present invention is applied to a reproducing head constituting a separate recording / reproducing magnetic head for DD. (A) is a perspective view in which a part of the magnetic head is cut off; () Is a partially enlarged view near the magnetoresistance effect element. In FIG. 9, reference numeral 901 denotes a magnetoresistive element, reference numeral 902 denotes a buffer member, reference numeral 903 denotes a spin-valve structure, reference numeral 904 denotes a hard film, reference numeral 905 denotes an MR electrode, and reference numeral 911. Is the reproducing head, 912 is the upper shield of the reproducing head, which also serves as the lower magnetic pole (922) of the recording head, 913, 914 are insulating films, and 915 is the reproducing The lower shield of the head, 916 is the substrate, 921 is the recording head, 922 is the upper ball of the recording head, 923 is the coil made of conductive material, and 924 is the playback. The lower pole of the recording head, which also serves as the upper shield (911) of the head, where the magnetic poles that make up the recording head are commonly called balls. The spin-valve structure 904 is a structure in which a free magnetic layer, a nonmagnetic layer, a fixed magnetic layer, and an antiferromagnetic layer (not shown) are sequentially stacked on a buffer member 903. The buffer member 903 according to the present invention and a spin-valve structure 9 provided thereon.

The portion of the magnetoresistive effect element 90 composed of the element 04 is sandwiched between the upper shield layer 912 and the lower shield layer 915 as a reproducing head 911.

The portion where 9 23 is sandwiched between the upper magnetic pole 9 2 2 and the lower magnetic pole 9 2 4 functions as the recording head 9 2 1. The read / write separated magnetic head according to the present invention is configured to also serve as the upper shield 9 12 force of the read head 9 11 and the lower magnetic pole 9 24 of the write head 9 21. In FIG. 9, the insulating film 914 and the lower shield 915 of the reproducing head 9 'function as a substrate 916 of the magnetoresistive element 901. In the above configuration, the reproducing head 901 according to the present invention has an alumina film having a sufficient thickness as the insulating films 913 and 914 above and below the magnetoresistive effect element 91 (total thickness of ~ 80 nm). The gap length (upper shield 9 12 and lower shield 9 1 5 .) Was realized. The MR ratio at this time was about 17% at room temperature and after film formation. In the above configuration, the upper shield 912 of the reproduction head 911 was connected to the lower pole of the recording head 921. Although the case where the upper pole 912 and the lower pole 9224 are made of different materials is described above, the upper shield 912 and the lower pole 9224 may have a laminated structure. The effect of the present invention is not lost even if the arrangement is made. Further, in the above description, the magnetoresistive effect element according to the present invention is applied to the read head constituting the read / write separated magnetic head. Although the case has been described, it goes without saying that the magnetoresistive element according to the present invention may be used for a read-only magnetic head.

Industrial applicability

As described above, according to the present invention, in a magnetoresistive effect element including an artificial lattice type structure or a spin valve type structure on a substrate, the ferromagnetic element positioned closest to the substrate among the structures On the substrate side of the body layer, one or more first elements selected from Si, B, C or Ge, and Fe, Ti, Cr, Mn, Co, Ni, By providing a buffer member composed of one or two or more second elements selected from Cu, Zr, Hί, or Ta, the in-plane crystal grain size of the ferromagnetic layer This greatly improves the flatness of the stack interface in the structure. Accordance connexion, device having a buffer member according to the present invention, without introducing a suitable amount of oxygen to the structure in as in the prior art, the magnetoresistive element comprising a _u above configuration can achieve a high MR ratio Since the structure is formed by eliminating oxygen as much as possible, even if high heat is applied to the element during use, various effects due to the movement of oxygen contained in the structure can be avoided, so that excellent heat It can also have strategic stability. The buffer member having the above effect is preferably in the form of a deposited layer formed on the surface of the substrate by deposition, but may be in another form, for example, a driving layer provided by doping the surface layer portion of the substrate. Les such may be in the form of, also buffer member according to the present invention, if oxygen as much as possible does not contain conditions, for example, produced by the vacuum back pressure to 1 0- ^{1 u} Torr table below space, Since the above-described functions and effects can be obtained, the manufacturing process of the buffer member and the manufacturing process of the structure need not necessarily be continuous in a vacuum process. That is, the surface of the buffer member after fabrication may be once exposed to the atmosphere. This enables a manufacturing process in which the manufacturing process of the buffer member and the manufacturing process of the structure are independent. For example, the present invention enables a process in which a base having a buffer member provided on a substrate in advance is prepared, and the base can be used in accordance with a request for a step of manufacturing a structure. Alternatively, the substrate itself can be easily distributed as a substrate for a magnetoresistance effect element. In addition, if the substrate having the buffer member according to the present invention is used, a high MR ratio and an excellent MR ratio can be obtained without changing the existing structure manufacturing process as long as the space has a reduced pressure of 10- ^lu Torr or less. Since the device having thermal stability can be easily formed, the characteristics of the device can be remarkably improved without further capital investment. Further, by incorporating the above-described magnetoresistive effect element into various magnetic heads, it becomes possible to provide a magnetoresistive effect sensor having extremely high sensitivity and excellent thermal reliability as compared with the related art.

Claims

The scope of the claims

1. A structure in which a ferromagnetic layer is laminated a plurality of times on a substrate with a non-magnetic layer interposed therebetween, or a ferromagnetic layer is laminated with a non-magnetic layer interposed therebetween, A magnetoresistive element having a structure in which an antiferromagnetic layer is formed on the surface of

A buffer member is provided on the substrate side of the ferromagnetic layer located closest to the substrate in the structure,

The buffer member includes one or more first elements selected from Si, B, C, and Ge, and Fe, Ti, Cr, Mn, Co, Ni, Cu, A magnetoresistance effect element comprising: one or more second elements selected from Zr, Hf, and Ta.

2. The magnetoresistive element according to claim 1, wherein the buffer member is a deposition layer.

3. The magnetoresistive element according to claim 1, wherein the buffer member comprises at least Fe and Si.

4. The magnetoresistive element according to claim 3, wherein the composition of the buffer member is Si of 2 atomic% to 36 atomic% and the balance Fe.

5. The magnetoresistive element according to claim 3, wherein the composition of the buffer member is Si of 4 at% to 26 at% and the balance Fe.

6. Place a substrate in a reduced pressure space capable, the back pressure of the space 1 0 one ¹ "

Depressurizing to below Torr level,

On the substrate, one or two or more first elements selected from Si, B, C or Ge, and Fe, Ti, Cr, Mn, Co, Ni, Cu, Forming a deposition layer composed of a buffer member composed of one or two or more second elements selected from Zr, Hi, and Ta; and forming the substrate and the substrate composed of the deposition layer. Forming, and

A structure in which a ferromagnetic layer is laminated a plurality of times with a non-magnetic layer interposed therebetween, or a ferromagnetic layer with a non-magnetic layer interposed therebetween, on the deposition layer forming the surface of the base, and is provided last. Forming a structure having an antiferromagnetic layer formed on the surface of the ferromagnetic layer, A method for manufacturing a magnetoresistive effect element, comprising:

7. One or more first elements selected from S i, B, C or Ge and F e, T i, C r, M n, C o, N i, C u

, Zr, Hf or Ta, one or more second elements selected from the group consisting of: A step of reducing the back pressure of the deposition space to a level of 10 ^lu- Torr or less;

A step of dry-etching the deposited layer forming the surface of the substrate, a structure in which a ferromagnetic layer is laminated a plurality of times on the deposited layer after the dry-etching process with a non-magnetic layer interposed therebetween, or Forming a structure in which a ferromagnetic layer is laminated with a magnetic layer interposed therebetween and an antiferromagnetic layer is formed on the surface of the lastly provided ferromagnetic layer;

A method for manufacturing a magnetoresistive element, comprising:

8. At least one or more first elements selected from Si, B, C or Ge, and Fe, Ti, Cr, Mn, Co, And a buffer member composed of one or more second elements selected from Ni, Cu, Zr, Hf and Ta. Substrate.

9. The substrate according to claim 8, wherein the buffer member is a deposition layer.

1 0. The substrate was placed on the evacuable space, a step of depressurizing the back pressure of the space 1 0 ¹⁶ or less Torr stand,

At least one or two or more first elements selected from S i, B, C or Ge, and Fe, D i, C r, Mi, C o, N i are provided on at least the surface layer of the substrate. A buffer member composed of one or two or more second elements selected from Cu, Zr, Hf and Ta, and forming a substrate comprising the substrate and the buffer member Process and

A method for producing a substrate for a magnetoresistive element, comprising:

11. The magnetoresistive element according to claim 10, wherein the step of manufacturing the buffer member is a step of forming a deposition layer made of the buffer member on the substrate by a film forming process. Of manufacturing a substrate for use.

1 2. A magnetoresistive element consisting of a structure in which a ferromagnetic layer is laminated a plurality of times with a nonmagnetic layer interposed between

A buffer member is provided on the substrate side of the ferromagnetic layer closest to the substrate in the structure, wherein the buffer member is one or more selected from Si, B, C, and Ge A first element and one or more second elements selected from Fe, Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf or Ta; A magnetoresistive effect sensor comprising:

1 3. A magnetoresistive effect consisting of a structure in which a ferromagnetic layer is laminated on a substrate with a nonmagnetic layer interposed, and an antiferromagnetic layer is formed on the surface of the lastly provided ferromagnetic layer Element

A buffer member is provided on the substrate side of the ferromagnetic layer located near the substrate in the structure, and the buffer member is one or more selected from S i, B, C or Ge A first element and one or more second elements selected from Fe, Ti, Cr, Mn, Co, Ni, Cu, Zr, Hf or Ta; A magnetoresistive effect sensor comprising: