CN100435346C - Light emitting devices - Google Patents

Abstract

Light-emitting devices, and related components, systems and methods are disclosed.

Description

Light-emitting device

Technical field

The present invention relates to a kind of light-emitting device and related elements, system and method.

Background technology

Compare with incandescent source and/or fluorescence source, light-emitting diode can provide the light of superior performance usually.Because the relatively high electrical efficiency relevant with LED causes using in many lighting installations LED to replace conventional light source.For example, in some applications, use LED as traffic lights, cell phone keyboard and display are used for throwing light on.

Generally speaking, LED is formed by sandwich construction, and wherein, the part layer at least in the sandwich construction is to be formed by different materials.Usually, selected material of each layer and the wavelength that thickness has determined the light of LED emission of being used for.In addition, can select the chemical composition of multilayer, enter specific region (being commonly referred to as quantum well), thereby be converted into luminous energy quite effectively with the electric carrier of attempting to avoid being injected.Usually, multi-layer doping on a side of the joint that quantum well generated has donor atom, thereby cause high electron concentration (this class layer is commonly referred to n type layer), the multilayer on opposite side then is doped with acceptor atom, causes high relatively hole concentration (this class layer is commonly referred to p-type layer).

Below will describe the contact of injection to the conventional method of making LED.Make a plurality of material layers with the form of disk.Generally speaking, use a kind of epitaxial deposition technique such as metal organic chemical vapor deposition (MOCVD) to form multilayer, the layer that begins deposit is formed on the growth substrates.Then, adopt various etchings and metallization technology with contacting of being formed for that electric current injects, then described disk is cut into LED wafer (LED chip) one by one multilayer.Usually, described LED wafer is encapsulated.

In use, generally electric energy is injected among the LED, is converted into electromagnetic radiation (light) then, the electromagnetic radiation (light) of part is sent from LED.

Summary of the invention

The present invention relates to a kind of light-emitting device and related elements, system and method.

In one embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.Ground floor comprises a surface, and the light that is produced the zone generation by light can send from described light-emitting device via the described surface of ground floor.Described surface has the dielectric function that spatially changes according to a figure (pattern), and described figure has desirable lattice constant and greater than zero the parameter of detuning.

In another embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.Ground floor comprises a surface, and the light that is produced the zone generation by light can send from described light-emitting device via the described surface of ground floor.Described surface has the dielectric function that spatially changes according to a non-periodic pattern.

In yet another embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.Ground floor comprises a surface, and the light that is produced the zone generation by light can send from described light-emitting device via the described surface of ground floor.Described surface has the dielectric function that spatially changes according to a complex periodic pattern.

In one embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises that a n-dopant material layer, a p-dopant material layer and light produce the zone.Described light-emitting device also comprises a layer of reflective material, and this layer of reflective material can reflect by light and produce produce and at least 50% light that strike described layer of reflective material in zone.The surface of n-dopant material layer is configured, and makes that producing the regional light that produces by light can send from described light-emitting device via the surface of the described n-of having dopant material layer.The surface of described n-dopant material layer has the dielectric function that spatially changes according to a figure.Distance between p-dopant material layer and n-dopant material layer is less than the distance between n-dopant material layer and layer of reflective material.

In another embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.Ground floor comprises a surface, and the light that is produced the zone generation by light can send from described light-emitting device via the described surface of ground floor.The surface of described ground floor has the dielectric function that spatially changes according to a figure.Described light-emitting device also comprises a layer of reflective material, and this layer of reflective material can reflect by light and produce produce and at least 50% light that strike described layer of reflective material in zone.Described light produces the zone between layer of reflective material and ground floor, and described figure does not extend beyond ground floor.

In yet another embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.The surface of ground floor is configured, and makes that producing the regional light that produces by light can send from described light-emitting device via the described surface of ground floor.Described light produces the zone and also comprises the material that contacts with the surface of ground floor, and this material has the refraction coefficient less than 1.5.Described generating means is encapsulated.

In one embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.The surface of ground floor is configured, and makes that producing the regional light that produces by light can send from described light-emitting device via the described surface of ground floor.The surface of described ground floor has the dielectric function that spatially changes according to a figure.Described light-emitting device also comprises the phosphate material by the surface bearing of described ground floor.The side of described light-emitting device does not have phosphate material in fact.

In another embodiment, the invention is characterized in the method for making disk.This method is included in deposit phosphate material on the surface of disk.This disk comprises a plurality of light-emitting devices.Each light-emitting device comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.The surface of ground floor is configured, and makes that producing the regional light that produces by light can send from described light-emitting device via the described surface of ground floor.The surface of described ground floor has the dielectric function that spatially changes according to a figure.

In yet another embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.The surface of ground floor is configured, and makes that producing the regional light that produces by light can send from described light-emitting device via the described surface of ground floor.The surface of described ground floor has the dielectric function that spatially changes according to a figure.Described light-emitting device also comprises a phosphate material, makes to be contacted with described phosphate material by light-emitting device light that produce, that send from the surface of ground floor, thereby makes the light that sends from described phosphorus layer be essentially white light.The height of light-emitting device and the ratio of its area are small enough to make white light to extend in any direction.

In one embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.The surface of ground floor is configured, and makes that producing the regional light that produces by light can send from described light-emitting device via the described surface of ground floor.Described light-emitting device also comprises first thin slice and second thin slice, and wherein first thin slice is by forming the light material transparent of sending from the surface of ground floor in fact, and second thin slice comprises phosphate material.Second thin slice is adjacent with first thin slice.Light-emitting device is packed, and first thin slice and second thin slice have formed the part of the encapsulation of light-emitting device.

In another embodiment, light-emitting device of the present invention is characterised in that and comprises a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.The surface of ground floor is configured, and makes that producing the regional light that produces by light can send from described light-emitting device via the described surface of ground floor.The surface of described ground floor has the dielectric function that spatially changes according to a figure.Described figure is configured to make that to produce the collimation of light that the zone produces, that send from light-emitting device through the surface of ground floor by described light better than the laplacian distribution (lambertian distribution) of light.

In yet another embodiment, the invention is characterized in that disk comprises a plurality of light-emitting devices.At least some light-emitting devices comprise a multiple layer stack.Described multiple layer stack comprises light generation zone and is produced the ground floor of area supporting by light.The surface of ground floor is configured, and makes that producing the regional light that produces by light can send from described light-emitting device via the described surface of ground floor.The surface of described ground floor has the dielectric function that spatially changes according to a figure.Described figure is configured to make that to produce the collimation of light that the zone produces, that send from light-emitting device through the surface of ground floor by described light better than the laplacian distribution of light.Described disk has about at least 5 (for example, about at least 25, about at least 50) light-emitting devices on every square centimeter.

In one embodiment, the invention is characterized in that light-emitting device comprises a multiple layer stack.Described multiple layer stack comprises that a light produces the zone and produces the ground floor of area supporting by light, makes during using light-emitting device, and producing the light that the zone produces by light can send from described light-emitting device via the described surface of ground floor.The surface of described ground floor has the dielectric function that spatially changes according to a figure.About at least 45% (for example, about at least 50%, about at least 60%, about at least 70%) that is produced light total amount that the zone produces, that send from described light-emitting device by light sends through the surface of light-emitting device.

In one embodiment, the invention is characterized in that light-emitting device comprises a multiple layer stack.Described multiple layer stack comprises that a light produces the zone and produces the ground floor of area supporting by light, makes when using light-emitting device, and producing the light that the zone produces by light can send from described light-emitting device via the described surface of ground floor.Described light-emitting device has an edge, and this edge grows to less about 1 millimeter (for example, about at least 1.5 millimeters, about at least 2 millimeters, about at least 2.5 millimeters).Design described light-emitting device, make that its ejection efficiency (extraction efficiency) is irrelevant with the length at edge in fact.

In yet another embodiment, the invention is characterized in that light-emitting device comprises a multiple layer stack.Described multiple layer stack comprises that a light produces the zone and produces the ground floor of area supporting by light, makes when using light-emitting device, and producing the light that the zone produces by light can send from described light-emitting device via the described surface of ground floor.Described light-emitting device has an edge, and this edge grows to less about 1 millimeter (for example, about at least 1.5 millimeters, about at least 2 millimeters, about at least 2.5 millimeters).Design described light-emitting device, make that its quantum efficiency (quantun efficiency) is irrelevant with the length at edge in fact.

In one embodiment, the invention is characterized in that light-emitting device comprises a multiple layer stack.Described multiple layer stack comprises that a light produces the zone and produces the ground floor of area supporting by light, makes when using light-emitting device, and producing the light that the zone produces by light can send from described light-emitting device via the described surface of ground floor.Described light-emitting device has an edge, and this edge grows to less about 1 millimeter (for example, about at least 1.5 millimeters, about at least 2 millimeters, about at least 2.5 millimeters).Design described light-emitting device, make that its photoelectric conversion efficiency (wall plug efficiency) is irrelevant with the length at edge in fact.

In another embodiment, the invention is characterized in the method for making light-emitting device.This method comprises layer of reflective material is combined with p-dopant material layer.Described light-emitting device comprises a multiple layer stack, and this multilayer comprises that p-dopant material layer, light produce zone and ground floor.Ground floor comprises a surface, and this surface has the dielectric function that spatially changes according to a figure.Described reflecting material can reflect by light and produce produce and at least 50% light that strike described layer of reflective material in zone.

In yet another embodiment, the invention is characterized in the method for making light-emitting device.The substrate desquamation that this method will combine with ground floor.Ground floor forms the part with multiple layer stack, and this multiple layer stack comprises that a light produces the zone.The surface of the ground floor of the light-emitting device that this method forms has a dielectric function, and this dielectric function spatially changes according to a figure.

The following describes one or more advantage of the present invention.

Described multiple layer stack can be formed by multiple layer stack of semiconductor materials.Ground floor can be the n-doped semiconductor material layer, and multiple layer stack may further include the p-doped semiconductor material layer.Light produces the zone can be between n-doped semiconductor material layer and p-doped semiconductor material layer.

Light-emitting device may further include the supporting member of the described multiple layer stack of supporting.

Light-emitting device further comprises a layer of reflective material, and described reflecting material can reflect by light and produce produce and at least 50% light that strike described layer of reflective material in zone.Layer of reflective material can be between supporting member and multiple layer stack.Distance between P-doped semiconductor material layer and the layer of reflective material can be less than the distance between n-doped semiconductor material layer and the layer of reflective material.Light-emitting device may further include the p type ohmic contact between p-dopant material layer and layer of reflective material.

Light-emitting device also can comprise the current spreading layer (current-spreading layer) between ground floor and light generation zone.

Multiple layer stack can be formed by semi-conducting material such as III-V semi-conducting material, organic semiconducting materials and/or silicon.

In certain embodiments, figure does not extend in the light inlet generation zone.

In certain embodiments, figure needn't extend on the ground floor.

In certain embodiments, figure extends beyond ground floor.

Light-emitting device further comprises and a plurality ofly electrically contacting, and is used for electric current is injected light-emitting device.Described electrically contact can be used for current vertical is injected light-emitting device.

Described figure can be partly by select in discontinuous texture and the combination thereof in the hole from the surface of (for example) ground floor, the pillar, continuous texture, ground floor in the ground floor in the ground floor one of form.

In certain embodiments, described figure can be selected from triangle, square figure and trellis figure.

In certain embodiments, figure can be selected from non-periodic pattern, accurate brilliant figure (quasicrystallinepatterns), Robinson's figure (Robinson pattern) and Amman figure (Amman patterns).In certain embodiments, figure is penrose diagramm (Penrose pattern).

In certain embodiments, figure can be selected from cellular pattern, Archimedes's figure.In certain embodiments, figure (for example, cellular pattern) can have the hole of different-diameter.

In certain embodiments, visuals ground is formed by the lip-deep hole at ground floor.

For example, detune parameter can be at least the ideal lattice constant 1% or be at most 25% of ideal lattice constant.In certain embodiments, figure can be corresponding to the desirable figure that detunes in fact arbitrarily.

Can dispose figure like this, the spectrum that the light that makes the surface of ground floor send has radiation mode, and to produce the feature emission spectra in zone identical with light on the spectrum essence of this radiation mode.

For example, light-emitting device can be Light-Emitting Diode, laser or image intensifer.The example of light-emitting device comprises organic light emitting apparatus (OLED), plane is emitting led and high brightness LED (HBLED).

In certain embodiments, the surface of ground floor has the feature of size less than λ/5, and wherein, λ is the wavelength of the ground floor light that can send.

In certain embodiments, the light-emitting device packed form of the tube core sealed (for example, with).In certain embodiments, the light-emitting device that has sealed can not adopt encapsulant.

In certain embodiments, the material that contacts with the surface of ground floor is gas (for example, air), and the pressure of this gas is approximately less than 100 holders (Torr).

In certain embodiments, the material that contacts with the surface of ground floor has and is approximately 1 refractive index at least.

In certain embodiments, encapsulated LED comprises a cover plate (cover).This cover plate can comprise phosphate material.This cover plate is configured to make light to produce zone light that produce, that send via the surface of ground floor and can interacts with phosphate material, make and send and send from described front cover, come down to white light with the interactional light of phosphate material via the surface of ground floor.

In certain some embodiment, light-emitting device further comprises first thin slice and second thin slice.First thin slice has the light material transparent to sending from light-emitting device in fact, and second thin slice comprises phosphate material.Second thin slice can be adjacent with first thin slice, refractive index can be arranged approximately less than 1.5 material between the surface of first thin slice and ground floor.First and second thin slices are configured to make light to produce zone light that produce, that send via the surface of ground floor and can interact with phosphate material, make and send and send from described second thin slice, come down to white light with the interactional light of phosphate material via the surface of ground floor.

Phosphate material can be placed on the surface of ground floor.

The method of making disk comprise place phosphate material with the variation that forms thickness approximately less than one deck of 20%.Described method can comprise the described layer of phosphor material of planarization, makes the varied in thickness of layer of phosphor material approximately less than 20%.Described method also is included in and places the described phosphate material of planarization after the phosphate material on the surface of ground floor.Described phosphate material can be spin-coated on the surface of disk by (for example).Described method comprises a plurality of light-emitting devices of formation from disk, and at least a portion light-emitting device is separated from each other out.

In certain embodiments, when produce by light light that the zone produces via the surface of ground floor when light-emitting device sends, the light that sends from the surface of ground floor about at least 40% to become about at most 30 to spend angles and send with the normal to a surface of ground floor.

In certain embodiments, the fill factor, curve factor of light-emitting device is about at least 10% and/or at most about 75%.

The method of making light-emitting device further is included in before layer of reflective material and the combination of p-dopant material layer, and with ground floor and substrate combination, multiple layer stack is between substrate and layer of reflective material.Described method also is included between ground floor and the substrate and forms binder course.Described method also comprises removes described substrate.Described method further is included in removes described substrate grinding and polishing step afterwards.After with layer of reflective material and ground floor combination, remove described substrate.Removing described substrate comprises the binder course between ground floor and described substrate is heated.Binder course heated to decompose to the small part binder course.Can comprise binder course heating binder course is exposed under the radiation of being sent by laser.Remove substrate and can comprise that the laser process of lifting exposes to substrate.Removing substrate causes the surface of ground floor to become coming down to smooth.Described method further is included in before the figure in the surface that forms ground floor, and planarization is carried out on the surface to ground floor after first substrate is removed.The flattening surface of ground floor comprised chemico-mechanical polishing is carried out on the surface of ground floor.The roughness on surface that planarization can reduce ground floor is carried out to approximately greater than λ/5 in the surface of ground floor, and wherein λ is the wavelength of the light that can be sent by ground floor.Form described figure and can comprise the little shadow of use nanometer.Described method can also comprise substrate is placed on the layer of reflective material.Described method may further include CURRENT DISTRIBUTION is placed between ground floor and the light generation zone.

Each embodiment has reflected following advantage of the present invention.

In certain embodiments, LED and/or big relatively LED wafer can send the relatively high light amount of drawing.

In certain embodiments, LED and/or big relatively LED wafer can send high relatively plane brightness, high relatively average surface brightness, low relatively radiating requirements or high relatively rate of heat dissipation, low relatively range (etendue) and/or high power efficiency relatively.

In certain embodiments, LED and/or big relatively LED wafer are designed such that the packed absorption of relatively small amount light of being sent by the LED/LED wafer.

In certain embodiments, can not use encapsulating material to make encapsulated LED (for example, big relatively encapsulated LED).This can be so that encapsulated LED be avoided the problem relevant with adopting some encapsulating material (as the performance that reduces and/or as the inconsistent performance of the function of time), has good relatively in considerable time and/or unfailing performance thereby provide.

In certain embodiments, LED (for example, can be the packaged LED of big relatively packaged LED) can comprise the relatively evenly phosphate material of spin coating.

In certain embodiments, LED (for example, can be the packaged LED of big relatively packaged LED) thus can be designed the light output that in specific angular range (for example, in the special angle scope with respect to the LED surface normal) provides hope.

In certain embodiments, can make LED and/or big relatively LED wafer with relatively cheap technology.

In certain embodiments, LED and/or big relatively LED can not increase under the cost, make via plant-scale mode, and can not cause infeasible economically.

The advantage of this aspect is put down in writing in specification, accompanying drawing and claims.

Description of drawings

Fig. 1 is the end view with LED of patterned surface.

Fig. 2 is the top view according to the patterned surface of the LED of Fig. 1.

Fig. 3 is the ejection efficiency figure with LED of patterned surface, and wherein patterned surface is the function that detunes parameter.

Fig. 4 is the schematic diagram of Fourier transformation of the patterned surface of LED.

Fig. 5 is the ejection efficiency with LED of patterned surface, and wherein, patterned surface is the function of minimum distance.

Fig. 6 is the ejection efficiency with LED of patterned surface, and wherein, patterned surface is the function of fill factor, curve factor.

Fig. 7 is the top view of the patterned surface of LED.

Fig. 8 is the ejection efficiency with LED of different surfacial patterns.

Fig. 9 is the ejection efficiency with LED of different surfacial patterns.

Figure 10 is the ejection efficiency with LED of different surfacial patterns.

Figure 11 is the ejection efficiency with LED of different surfacial patterns.

Figure 12 is the schematic diagram with fourier transform of two LED that compare different patterned surfaces with the radiation spectrum of LED.

Figure 13 is the figure that has as the ejection efficiency of the LED of the different surfaces figure of the function of angle.

Figure 14 is the end view with LED of patterned surface and the phosphate material on patterned surface.

Figure 15 is the end view of epitaxial layer precursor (precursor) with LED of patterned surface.

Figure 16 is the end view of epitaxial layer precursor with LED of patterned surface.

Figure 17 is the end view of epitaxial layer precursor with LED of patterned surface.

Figure 18 is the end view of epitaxial layer precursor with LED of patterned surface.

Figure 19 is the end view of epitaxial layer precursor with LED of patterned surface.

Reference numeral identical in each accompanying drawing is represented components identical.

Embodiment

Fig. 1 illustrates the end view of the LED that is the package die form.LED100 comprises the multiple layer stack 122 that places on the carrier.Multiple layer stack 122 comprises silicon doping (n-doping) the GaN layer 134 of 320 nanometer thickness, has formed the figure of a plurality of openings 150 at silicon doping (n-doping) upper surface 110 of GaN layer 134.Multiple layer stack 122 comprises that also the magnesium of silver layer 126,40 nanometer thickness of binder course 124,100 nanometer thickness mixes (p-dopings) GaN layer 128, the light generation regional 130 and the AlGaN layer 132 of 120 nanometer thickness that formed by a plurality of InGaN/GaN quantum well.The N-side contact pad places on the layer 134, and p-side contact layer 138 places on the layer 126.Encapsulating material (epoxy resin with 1.5 refractive indexes) is positioned between layer 134 and cover slip (cover slip) 140 and the strutting piece 142.Layer 144 does not extend into opening 150.

The following generation light of LED.P-side contact pad 138 relative n-side contact pad 136 cause electric current to inject LED100 for positive potential.When electric current produces in the zone 130 through light, just combine with hole from the electronics of n-doped layer 134 from p-doped layer 128 regional 130, make light produce zone 130 generation light.Light produces zone 130 and is included in light and produces emit beam a plurality of dipole point sources of (for example, isotropism) of zone, and described light has and forms the spectral signature of wavelength that light produces the material in zone 130.Under the effect of InGaN/GaN quantum well, the spectrum of the wavelength of the light that produced by zone 130 can have the spike wavelength of about 445 nanometers and half maximum overall with (FWHM) of about 30 nanometers.

Notice that the charge carrier in p-doped layer 126 is compared with the charge carrier in the n-doping semiconductor layer 134 has relative low mobility.Therefore, place silver layer 126 (it conducts electricity) along the surface of p-doped layer 128 and can improve the electric charge uniformity of injecting p-doped layer 128 and light generation zone 130 by contact mat 138.This can also reduce the injection efficiency of the resistance and/or the increase equipment 100 of equipment 100.Because the higher relatively electric charge mobility of n-doped layer 134, electronics can diffuse through layer 132 and 134 from n-side contact pad 136 relatively soon, thereby the current concentration that produces in the zone 130 at light in fact evenly passes through zone 130.Be also noted that it is electrical that silver layer 126 has high relatively thermal conductance, allow layer 126 a thermal source (with heat from multiple layer stack 122 vertical transmissions to carrier 120) as LED100.

At least a portion light that is produced by zone 130 can be directed to silver layer 126.This light can tegillum 126 reflections and 110 send from LED100 through the surface, perhaps can in the semi-conducting material of LED100, absorb then by layer 126 reflection, can in zone 130, combination cause zone 130 to produce the electron-hole pair of light thereby form.Similarly, produce at least a portion light by zone 130 and be directed to pad 136.Pad 136 downside is formed by the material (for example, Ti/Al/Ni/Au alloy) that can reverberation produces at least a portion light that zone 130 produces.Therefore, the light that is directed to pad 136 can (for example sent from LED100 through surface 110 then by pad 136 reflections, by reflection from silver layer 126), the perhaps described light that is directed to pad 136 can be by pad 136 reflections, in the semi-conducting material of LED100, absorb then, thereby produce can be in zone 130 combination cause zone 130 to produce the electron-hole pair of light (for example, by or can't help silver layer 126 reflections).

As illustrated in fig. 1 and 2, the surface 110 of LED100 is uneven, but is formed by the opening 150 of the triangular pattern of revising.In a word, can be that the degree of depth of opening 150 is selected different values, nearest distance can change between the diameter of opening 150 and the adjacent apertures 150.Unless adopting other modes is explained, otherwise adopt numerical computations that each figure is described: opening 150 has the degree of depth 146 that equals about 280 nanometers, the non-zero diameter of about 160 nanometers, the distance between the adjacent apertures is approximately 220 nanometers and equals 1.0 refractive index.The diabolo figure detunes processing, thereby has value in the figure 150 between the most adjacent for (the a-Δ is a) to (centre distance of a+ Δ between a), wherein " a " is the lattice constant of ideal triangular pattern, " Δ a " for having the parameter of detuning of length dimension, described detuning can be gone up generation in any direction.In order to improve the light amount of sending from LED100 of drawing (referring to following explanation), detune parameter Δ a be generally ideal lattice constant a about at least 1% (for example, at least about 2%, at least about 3%, about at least 4%, about at least 5%), and be approximately at most ideal lattice constant a 25% (for example, be approximately 20% at most, be approximately 15% at most, be approximately 10% at most).In certain embodiments, the most adjacent interval (the a-Δ a) to (arbitrary value of a+ Δ between a), thus figure 150 can be detuned arbitrarily in fact.

For the correction triangular pattern that has opening 150, have been found that non-zero detunes the taking-up efficiency that parameter has improved LED100.For above-mentioned LED100, be increased to about 0.15a when detuning parameter Δ a from zero, the ejection efficiency that the Mathematical Modeling of the electromagnetic field in LED100 (introducing hereinafter) shows device is added to about 0.70 from about 0.60, as shown in Figure 3.

Ejection efficiency among Fig. 3 is by using Three dimensional finite difference time domain (FDTD) method to calculate to think in the LED100 or outer light is estimated for example separating of Maxwell equation, referring to K.S.Kunz and R.J.Luebbers, The Finite-Difference Time-DomainMethods (CRC, Boca Raton, FL, 1993), A.Taflove, ComputationalElectrodynamics:The Finite-Difference Time-Domain Method (ArtechHouse, London, 1995), these documents are attached to the present invention by reference.In order to present the optical of LED100 with special pattern 150, input parameter in FDTD calculates comprises the bandwidth of the light that centre frequency and the dipole point source in light generation zone 130 send, the size and the dielectric property of each layer in multiple stacked material layers 122, and diameter, the degree of depth, and the most adjacent distance (NND) between the opening in the figure 150.

In certain embodiments, use the ejection efficiency data of the following calculating of FDTD method LED100.Use FDTD to solve omnidirectional and measure time-based Maxwell equation:

$\stackrel{\→}{\▿}\×\stackrel{\→}{E}=-\mathrm{\μ}\frac{\∂\stackrel{\→}{H}}{\∂t},$ $\stackrel{\→}{\▿}\×\stackrel{\→}{H}={\mathrm{\ϵ}}_{\∞}\frac{\∂\stackrel{\→}{E}}{\∂t}+\frac{\∂\stackrel{\→}{P}}{\∂t},$

Wherein, polarityization $\stackrel{\→}{P}={\stackrel{\→}{P}}_1+{\stackrel{\→}{P}}_2+...{\stackrel{\→}{P}}_m$ The response that depends on frequency of other layers among quantum well, p-contact layer 126 and the LED100 in seizure light generation zone 130. Item is the experience derivation values (for example, the polarity response of bound electron vibration, the polarity response of free electron vibration) that the integral polarityization of material had different contributions.Especially,

$\frac{d^2{\stackrel{\&RightArrow;}{P}}_m}{\mathrm{<figure-callout\; id="2"\; label="d\; t"\; filenames="C20048001036900421.png,C20048001036900431.png"\; state="\{\{state\}\}">d</figure-callout>}{t}^{}{}^2}+{\mathrm{\&gamma;}}_m\frac{d{\stackrel{\&RightArrow;}{P}}_m}{\mathrm{dt}}+{\mathrm{\&omega;}}_m^2{\stackrel{\&RightArrow;}{P}}_m=\mathrm{\&epsiv;}\left(\mathrm{\&omega;}\right)\stackrel{\&RightArrow;}{E},$

Wherein, polarityization is corresponding to a dielectric constant

$\mathrm{\&epsiv;}\left(\mathrm{\&omega;}\right)={\mathrm{\&epsiv;}}_{\&infin;}+\underset{m}{\mathrm{\&Sigma;}}\frac{s_m}{{\mathrm{\&omega;}}_m^2-{\mathrm{\&omega;}}^2-i{\mathrm{\&gamma;}}_m\mathrm{\&omega;}}$

Numerical computations has only been considered encapsulating material 144, silver layer 126 and each layer between encapsulating material 144 and silver layer 126 for convenience.This approximate evaluation is enough thick based on hypothesis encapsulating material 144 and layer 126, makes peripheral layer not influence the optical property of LED100.The dependency structure of supposing to have among the LED100 of the dielectric constant that relies on frequency is that silver layer 126 and light produce zone 130.Suppose that other relevant layers among the LED100 do not rely on the dielectric constant of frequency.Notice, comprise at LED100 among the embodiment of the additional metal layer between encapsulating material 144 and silver layer 126 that each additional metal layer will have the dielectric constant that relies on frequency.Also must note, the item that silver layer (with any other layer among the LED100) has the dependence frequency that is used for bound electron and free electron, and light produces the item that the zone has the dependence frequency that is used for bound electron, but the item that does not have the dependence frequency that is used for free electron.In certain embodiments, when the frequency dependence of modelling dielectric constant, can comprise other item.For example, such item can comprise the sub-interaction of electroacoustic, atom polarization, ionic polarization and/or molecular polarization.

By being combined in the dipole source of the constant current of placing arbitrarily in the light generation zone 130, the light that the quantum well in modelling light generation zone 130 is sent, the short Gaussian pulse of each emission of spectral width equals the Gaussian pulse of actual quantum well, and each has random initial phase, time started.

Figure for the opening 150 on the surface 110 of handling LED100 uses bigger super element (supercell) and periodic boundary condition in the side direction.This can help simulation big (for example, on the edge greater than 0.01 millimeter) plant bulk.After all dipole sources have sent their energy, in system, there is not energy, solve full EVOLUTION EQUATION in real time.In this emulation, the gross energy that sends, be monitored via the energy of upper surface 110 stream and by the energy of quantum well with the absorption of n-doped layer.By the Fourier transformation on time domain and space, obtain to draw the frequency and the angle resolution data of stream, therefore, can resolve ejection efficiency by calculated rate.The experiment known luminescence that produces zone 130 by the gross energy that will send and light is mated, and the absolute angle that obtains unit brightness, unit wafer area for given input is resolved and drawn.

What can be sure of is, because opening 150 has been set up the dielectric function that changes on the space according to figure 150 in layer 134, change and detune figure 150 can improve the light that sends via the 110 clumps of LED100 in surface, produce in light generation zone 130 efficient, this is not equal to notional result.Can also be sure of that The above results has changed radiation mode at LED100 (for example, sending the optical mode attitude of light from surface 110) and guided the concentration of mode (for example, be limited in the multiple stack layer 122 optical mode attitude).And this to LED100 radiation mode and the change of the concentration of guiding mode cause some light (for example to be scattered, Bragg diffraction) inject in the mode that can leak into radiation mode, more described light are launched under the situation that does not have figure 150 in the guiding mode.In certain embodiments, be sure of figure 150 (for example, above-mentioned figure, perhaps an above-mentioned figure) can eliminate among the LED100 all the guiding mode.

Can be sure of that the Bragg diffraction of the crystal by considering to have the point scattering position is appreciated that the effect of detuning of lattice.For with the perfect lattice in the lattice plane of distance d space, wavelength is that the monochromatic light of λ adopts an angle θ to carry out scattering according to Bragg condition n λ=2dsin θ, and wherein n is the integer of the exponent number of expression scattering.Yet,,, Bragg condition can be relaxed one and detune parameter Δ a by detuning the interval between the lattice sites for having spectral bandwidth Δ λ/λ and injecting for the source with three-dimensional viewpoin Δ Θ.Detuning of lattice improved the scattering validity of the figure on the spatial emission profile in spectral bandwidth and source and accepted angle.

Though by the agency of have correction triangle 150 that non-zero detunes parameter Δ a and can increase the light amount of drawing from LED100, can also use other figure to increase the light amount of drawing from LED100.When determining whether given figure increases can be used for increasing the light amount of drawing from LED100 from the light amount of drawing of LED100 and/or which kind of opening figure the time, before carrying out numerical computations, at first use physical image (physical insight) to come approximate evaluation can increase the fundamental figure of the light amount of drawing.

By consider spatially to change according to figure 150 the Fourier transformation of dielectric constant, the taking-up efficient of LED100 can further be understood (for example, in the weak scattering condition).Fig. 4 has illustrated the Fourier transformation to ideal triangular lattice.Draw and the wave vector k ' (that is, being parallel to figure 150) in the plane of the light that the specific direction of wave vector k enters in the plane enter the emission source S of all radiation mode _{K '}Mutual connection is arranged, and wherein, wave vector k can add or deduct the vector of falling lattice G by wave vector k ' in the plane and obtains in the plane, i.e. k=k ' ± G.Ejection efficiency is proportional to dielectric function ε _GDeal with upright leaf component (F mutually _k) amplitude, provide by following formula

$F_{\stackrel{\&RightArrow;}{k}}=c_{\stackrel{\&RightArrow;}{k}}\underset{\stackrel{\&RightArrow;}{G}}{\mathrm{\&Sigma;}}{\mathrm{\&epsiv;}}_{\stackrel{\&RightArrow;}{G}}{S}_{\stackrel{\&RightArrow;}{k}-\stackrel{\&RightArrow;}{G}},$ ${\mathrm{\&epsiv;}}_{\stackrel{\&RightArrow;}{G}}=\&Integral;\mathrm{\&epsiv;}\left(\stackrel{\&RightArrow;}{r}\right)e^{-i\stackrel{\&RightArrow;}{G}\stackrel{\&RightArrow;}{r}}d\stackrel{\&RightArrow;}{r}$

Because equation k is satisfied in the propagation of light in material usually ²(in the plane)+k ²(normal direction)=ε (ω/c) ², the maximum G that is considered is produced the frequency (ω) of zone emission by light and the dielectric constant in light generation zone is fixed.As shown in Figure 4, defined the ring of the reciprocal space that is commonly called luminous energy rank (light line).Because light produces the finite bandwidth in zone 130, described luminous energy rank are circulus, but for convenience of explanation, describe on these luminous energy rank with monochromatic source.Similarly, the light in encapsulating material is propagated the restriction that also is subjected to luminous energy rank (the interior ring among Fig. 4).Therefore, the scattering strength ε of ordering by Fk that is increased in all direction k in these encapsulating material luminous energy rank and the G that increases on the encapsulating material luminous energy rank _G, ejection efficiency can improve, and wherein, the luminous energy rank in the encapsulating material layer equal the increment summation that the G in the encapsulating material layer is ordered.When selecting to improve the figure that takes out efficient, can use this physical image.

For example, Fig. 5 shows the effect of the lattice constant that increases ideal triangular pattern.Data among Fig. 5 are to use the given calculation of parameter of the LED100 shown in Fig. 1 to get, but the ejaculation light that does not comprise spike wavelength with 450 nanometers, the thickness of the degree of depth of the perforate when being respectively 1.27a, 0.72a, 1.27a+40nm, the diameter of perforate and n-doped layer 134 with nearest neighbor distance " a ".Increase the concentration that G that lattice constant then increases the luminous energy rank of having built encapsulating material is ordered.Observe the trend of knowing of ejection efficiency with NND.Can be sure of, be approximately equal to optical wavelength in the vacuum for the maximum ejection efficiency of NND.The reason that obtains maximum ejection efficiency is: when NND becomes greater than optical wavelength, because material becomes more even, reduced scattering effect.

For example, Fig. 6 shows the effect that increases hole dimension or fill factor, curve factor.The fill factor, curve factor of triangular pattern is by (2 π/√ 3) * (r/a) ²Provide, wherein, r is the radius in hole.Data among Fig. 6 are to use the given calculation of parameter of the LED100 that is used for Fig. 1 to come out, and these parameters do not comprise the opening diameter that changes according to the given fill factor, curve factor on the x axle.As scattering strength (ε _G) when increasing, ejection efficiency increases along with fill factor, curve factor.When fill factor, curve factor was～48%, then this particular system had maximum.In certain embodiments, LED100 has the fill factor, curve factor of about at least 10% (for example, about at least 15%, about at least 20%) and/or about at most 90% (for example, about at most 80%, about at most 70%, maximum about 60%).

Though it is relevant with location at the figure opening of the position of ideal triangular lattice to detune parameter in the correction triangular pattern of above-mentioned introduction, by revising the center that hole in the ideal triangular figure keeps the position of ideal triangular figure simultaneously, (detuning) triangular pattern that also can obtain to revise.Fig. 7 shows an embodiment of this figure.The increase of the light amount of drawing, it is identical with said method with method for the physical interpretation of the light amount of drawing of the increase of the light-emitting device with figure shown in Figure 7 to be used to carry out corresponding numerical computations.In certain embodiments, (detuning) figure of correction can have place apart from the opening of ideal position and at ideal position but have the opening of different-diameter.

In other embodiment, by using different figures, comprise (for example) complex periodic pattern and non-periodic pattern, can obtain from the light amount of drawing of the increase of light-emitting device.At this, complex periodic pattern is a kind of like this figure, and its each cell cube (unit cell) of carrying out repetition with periodic manner has more than one feature.For example, the complex periodic figure comprises cellular pattern, honeycomb substrates figure, (2x2) base patterns, ring-shaped figure and Archimedes's figure.As described below, in certain embodiments, complex periodic pattern can have some openings that have a diameter and have more other opening of minor diameter.At this, non-periodic pattern is such figure, does not have translational symmetry on the cell cube of at least 50 times length of the spike wavelength with the light that produce for zone 130.The example of non-periodic pattern comprises non-periodic pattern, accurate brilliant figure, Robinson's figure and Amman figure.

Fig. 8 shows the numerical computations to LED100, two kinds of different complex periodic pattern, and wherein some opening in the figure has special diameter, and other openings in the figure have than minor diameter.Numerical computations shown in Fig. 8 illustrates to be had than the diameter of aperture (dR) performance from the 0 taking-up efficient that changes to 95 nanometers (have 80 nanometer diameters than macropore).Data shown in Fig. 6 are to use the given parameter of the LED100 that is used for Fig. 1 to calculate, and described given parameter does not comprise the diameter of the opening that changes according to the given fill factor, curve factor value on the X-axis of figure.Not bound by theory, multiple hole dimension allows the multiple periodicity from figure to carry out scattering, thus increased figure accept angle and spectrum efficiency.The raising of the light amount of drawing is used to carry out the respective value Calculation Method, with for the physical interpretation of the ejection efficiency of the raising of the light-emitting device of figure with Fig. 8 all with above-mentioned introduce identical.

Fig. 9 illustrates the numerical computations of the LED100 with different ring-shaped figures (complex periodic pattern).Is different (6,8 or 10) around the perforate number in first annular of centre bore for different ring-shaped figures.Data shown in Fig. 9 are to use the given calculation of parameter of the LED100 among Fig. 1 to come out, and described given parameter does not comprise the emission light of the spike wavelength with 450 nanometers.Numerical computations among Fig. 9 shows the ejection efficiency of from 2 to 4 o'clock the LED100 of figure quantity of every cell cube, and wherein ring-shaped figure passes through cell cube with repetitive mode.The increase of the light amount of drawing is used to carry out the respective value Calculation Method, with to the physical interpretation of the light extraction rate of the increase of light-emitting device with figure shown in Figure 9 with above-mentioned introduce identical.

Figure 10 illustrates the numerical computations of the LED100 with Archimedes's figure.Archimedes's figure A7 is that the hexagonal cells body 230 by the hole with 7 same intervals constitutes, and wherein neighbor distance each other is a.In cell cube 230, arrange according to orthohexagonal shape in 6 holes, and the 7th perforate is positioned at hexagonal center.Then, hexagonal cells body 230 with these holes with centre distance is $a^{,}=a^{*}(1+\sqrt{3}),$ And constitute the whole surface of LED jointly along the edge.Here it is, and said A7 fills, because a cell cube has been formed in 7 holes.Similarly, Archimedes A19 by 19 same intervals, have the most adjacent hole and form apart from a.Arrange in the form at interior hexagonal center with the outer hexagon and the centre bore in the interior hexagon with 7 holes, 12 holes in these holes.Then, with these holes be with centre distance $a^{,}=a^{*}(3+\sqrt{3}),$ And constitute the whole surface of LED jointly along the edge.The increase of the light amount of drawing is used to carry out the respective value Calculation Method, with to the physical interpretation of the light extraction rate of the increase of light-emitting device with figure shown in Figure 10 with above-mentioned introduce identical.As shown in figure 10, the ejection efficiency of A7 and A19 is approximately 77%.Data shown in Figure 10 are to use the given calculation of parameter of LED100 shown in Figure 1 to come out, and are not defined in the distance between the opening in each cell cube but described given parameter does not comprise the emission light of the spike wavelength with 450 nanometers and NND.

Figure 11 shows the numerical computations of the LED100 with accurate brilliant figure.Accurate brilliant figure is at (for example) M.Senechal, and Quasicrystals and Geometry (England 1996 for Cambridge UniversityPress, Cambridge) introduces, and is incorporated by reference at this.This numerical computations has illustrated the performance of ejection efficiency when changing based on 8 heavy quasi-periodic structures.Can be sure of that because quasicrystal structure allows axial symmetry in the high plane, accurate brilliant figure presents high ejection efficiency.The increase of the light amount of drawing is used to carry out the respective value Calculation Method, with to the physical interpretation of the light extraction rate of the increase of light-emitting device with figure shown in Figure 11 with above-mentioned introduce identical.The FDTD result calculated of Figure 11 shows that the ejection efficiency of accurate brilliant figure reaches about 82%.Data shown in Figure 11 are to use the given calculation of parameter of LED100 shown in Figure 1 to come out, and are not defined in the distance between the opening in each cell cube but described given parameter does not comprise the emission light of the spike wavelength with 450 nanometers and NND.

Though, be to be understood that, also be the ejection efficiency that can improve LED100 if other figures satisfy above-mentioned basic principle at this example of introducing some figures.For example, aligning crystalline substance or detuning of complicated periodic structure can be sure of to increase and ejection efficiency can be increased.

In certain embodiments, that send by LED100 and produce by light the light that zone 130 produces total amount about at least 45% (for example, at least about 50%, at least about 55%, at least about 60%, about at least 70%, about at least 80%, at least about 90%, about at least 95%) send through surface 110.

In certain embodiments, the sectional area of LED100 can be relatively big, still can present effective light ejection efficiency of LED100.For example, one or more edges of LED100 can be about at least 1 millimeter (for example, about at least 1.5 millimeters, at least about 2 millimeters, about at least 2.5 millimeters, about at least 3 millimeters), and total amount about at least 45% that sent by LED100 and that produce the light that zone 130 produces by light (for example, at least about 50%, about at least 55%, about at least 60%, at least about 70%, at least about 80%, about at least 90%, about at least 95%) send through surface 110.This allows LED to have big relatively sectional area (for example, being about at least 1 millimeter of about at least 1 millimeter x), presents good power conversion efficiency simultaneously.

In certain embodiments, it is irrelevant with the length at LED edge in fact to have the ejection efficiency of LED of LED100 design.For example, the ejection efficiency at one or more edges that has the design of LED100 and have about 0.25 millimeter length is with have the design of LED 100 and have the difference of ejection efficiency at one or more edges of 1 millimeter length can be less than about 10% (for example, less than about 8%, less than about 5, less than about 3%).At this, the ejection efficiency of LED is the ratio of the light total amount (can measure according to the energy of photon) sent of the light that sends of LED and this device.This allows LED to have big relatively cross section (for example, about at least 1 millimeter of about at least 1 millimeter x), and still presents good performance.

In certain embodiments, it is irrelevant with the length at LED edge in fact to have the quantum efficiency of LED of LED100 design.For example, the quantum efficiency at one or more edges that has the design of LED100 and have about 0.25 millimeter length is with have the design of LED100 and have the difference of quantum efficiency at one or more edges of 1 millimeter length can be less than about 10% (for example, less than about 8%, less than about 5, less than about 3%).At this, the quantum efficiency of LED is the ratio of the number that closes of LED photon numbers that produces and the electronics-hole recombination that takes place in LED.This allows LED to have big relatively cross section (for example, about at least 1 millimeter of about at least 1 millimeter x), and still presents good performance.

In certain embodiments, it is irrelevant with the edge of LED in fact to have the electro-optical efficiency (wall plug efficiency) of LED of design of LED100.For example, the photoelectric conversion efficiency at one or more edges that has the design of LED100 and have about 0.25 millimeter length is with have the design of LED100 and have the difference of photoelectric conversion efficiency at one or more edges of 1 millimeter length can be less than about 10% (for example, less than about 8%, less than about 5, less than about 3%).At this, the photoelectric conversion efficiency of LED is: the injection efficiency of LED (number of the carrier of injection device and produce the ratio of in the zone carrier number of recombination at the light of light-emitting device), the product of the ejection efficiency (from the photon number of LED and the total number of light photons purpose ratio of generation) of the radiation efficiency of LED (causing the electronics-hole recombination of radiation to close the ratio of the total number that closes with electronics-hole recombination) and LED.This allows LED to have big relatively cross section (for example, about at least 1 millimeter of about at least 1 millimeter x), and still presents good performance.

In certain embodiments, controlling by LED100 will be desirable through the angular distribution of surface 110 light that send.(for example enter given three-dimensional viewpoin (given solid angle) in order to increase, enter a three-dimensional viewpoin that is centered around surface 110 normal direction) ejection efficiency, check that according to figure 150 (as mentioned above) carry out the Fourier transformation of the dielectric function that changes on the space.Figure 12 shows the Fourier transform construction of two ideal triangular lattice with different lattice constants.In order to improve ejection efficiency, we seek to increase the scattering strength (ε that number that the G in the encapsulating material luminous energy rank orders and the G in the material luminous energy rank are ordered _G).This means that thereby increasing NND obtains the effect that Fig. 5 describes.Yet in this care is that to enter with the normal direction be the ejection efficiency of the three-dimensional viewpoin at center.Therefore, by reducing the radius on encapsulating material luminous energy rank, limited the introducing that high-order G is ordered, the amplitude of G is greater than (ω (n like this _e))/c.Hence one can see that, by reducing the refractive index (Minimum requirements is that all encapsulating materials are removed) of encapsulating material, can allow bigger NND, thereby increase the number that the G in material luminous energy rank is ordered, and these material luminous energy rank can help at normal direction (F _kDrawing=0) avoided the diffraction that becomes high-order (angle of inclination) in the encapsulating material simultaneously.Figure 13 shows above-mentioned introduction, and it shows the ejection efficiency that enters three-dimensional viewpoin (being provided by the set half-angle among the figure).Data among Figure 13 are to use the given calculation of parameter of the LED100 of Fig. 1 to come out, these given parameters do not comprise: the ejaculation light with bandwidth of the spike wavelength of 530 nanometers and 34 nanometers, 1.0 the refractive index of encapsulating material, the thickness of the p-doped layer of 160 nanometers, the light-generating layer that 30 nanometers are thick, the NND (a) of three curves shown in Figure 13 and be respectively a, 1.27a, the degree of depth when 0.72a, 1.27a+40nm, bore dia and n-doped layer thickness.When lattice constant increases, also increase at the ejection efficiency of narrow angular and the ejection efficiency that enters all angles.Yet, for bigger lattice constant, increase even enter the whole ejection efficiency of all angles, enter the higher order of modes in the encapsulating material diffraction-limited at the ejection efficiency of narrow angular.For the lattice constant of 460 nanometers, calculate enter the set half-angle ejection efficiency greater than 25%.That is, only the only about half of light of drawing in the episphere of about 13.4% three-dimensional viewpoin is collected, and presents the aiming effect (collimation effect) of figure.Can be sure of that the figure that the number that any G that can increase material luminous energy rank is ordered, the G when limiting number that the G in the encapsulating material luminous energy rank orders and be k=0 are simultaneously ordered can improve that to enter with the normal direction be the ejection efficiency of the three-dimensional viewpoin at center.

Said method is particularly useful for reduction and is proportional to n usually ²The source range, wherein n represents the refractive index of material around (for example, encapsulating material).Therefore, the refractive index that can be sure of to reduce the encapsulating material layer of LED 100 can cause more parallel emission, less source range and higher surface brightness (being defined herein as the total brightness of introducing source range).In certain embodiments, use the encapsulating material of air can reduce the source range, increase simultaneously enters with the normal direction ejection efficiency of the given collection angle that is the center.

In certain embodiments, when LED100 sent, the collimation of the distribution of light was better than laplacian distribution through surface 110 for the light that produce when zone 130.For example, in certain embodiments, the light that produce when zone 130 through surface 110 when LED100 sends, about at least 40% (for example, about at least 50%, about at least 70% of the light that sends through the surface of dielectric layer, at least about 90%) to become about at most 30 degree with surperficial 110 normal direction (for example, about at the most 25 the degree, about at the most 20 the degree, about at the most 15 the degree) angle send.

Draw the ability of a high proportion of relatively light under desired angle, perhaps the high light line extraction rate can allow to make highdensity relatively LED on given disk relatively.For example, in certain embodiments, on every square centimeter disk, have about at least 5 LED (for example, about at least 25 LED, about at least 50 LED).

In certain embodiments, wish to revise the wavelength that encapsulates the light that LED100 sends certainly that produces the wavelength of the light that zone 130 produces with respect to light.For example, as shown in figure 14, LED300 has the layer 180 that comprises phosphate material, and this layer can be placed on surface 110.Described phosphate material can interact with the light of the wavelength that is produced by zone 130, so that the light of desired wavelength to be provided.In certain embodiments, expect that the light that sends from LED100 is essentially white light.In these embodiments, the phosphate material of layer in 180 can (Y, Gd) (Al, Ga) (" YAG " (yttrium, aluminum, garent)) constitutes for G:Ce3+ or yttrium-aluminium-garnet by (for example).When being produced zone 130 blue lights that send by light and excited, the phosphate material in layers 180 can be activated and send that to have with the sodium yellow wavelength be the light (for example, isotropism) of the wide spectrum at center.To can seeing yellow phosphor broad emission spectrum, the narrow emission spectrum of blue light InGaN, and mix two kinds of spectrum usually for seeing white light via the observer of total spectrum that LED100 sent.

In certain embodiments, layer 180 can be placed in fact on the surface 110 equably.For example, the variation of distance on surface 110 between the top 151 of figure 150 and layer 180 the top 181 is less than about 20% (for example, less than about 10%, less than about 5%, less than about 2%).

In a word, with respect to the sectional dimension on the surface 130 of LED100, the thickness of layer 180 is little, and described sectional dimension is typically about 1 millimeter x1 millimeter.Because layer 180 is to be deposited on equably on the surface 110, the phosphate material of layer in 180 in fact can be by through the surface 110 light institute pumpings (pumped) of sending.Phosphorus layer 180 is compared relative thin with the size on the surface 110 of LED100, make light produce zone 130 light that send approximate equably LED100 whole surperficial 110 on phosphorus layer 180 in be converted into the light of low wavelength.Therefore, relative thin, uniformly phosphorus layer 180 produces the white light of the even spectrum of launching from LED100, it be the function of surperficial 110 position.

In a word, can make LED100 as required.Usually, the making of LED100 relates to each deposit, laser treatment, little shadow and etching step.

Referring to Figure 15, the LED disk 500 that comprises the LED layer stack that is deposited on the Sapphire Substrate 502 can use and can buy from suppliers and obtain.On Sapphire Substrate 502, be provided with resilient coating 504, n-doping Si:GaN layer 506, the AlGaN/GaN heterojunction that current-diffusion layer 180 is provided or superlattice, InGan/GaN Multiple Quantum Well light generation zone 510, p-doped with Mg in regular turn: GaN layer 512.Gong Ying LED disk diameter is approximately the 2-3 inch on the market, and after handling disk, obtains a plurality of LED tube cores and forms each device thereby can cut disk.Before the cutting disk, a plurality of wafer scale treatment steps are used to p-doped layer 128 is positioned at the same side that light produces zone 130, as reflection layer 126.

Referring to Figure 16, the nickel dam 520 of relative thin be deposited (for example making deposited by electron beam evaporation) on p-doped layer 512 to form p-type ohmic contact.Silver layer 522 is deposited (for example, making deposited by electron beam evaporation) on nickel dam 520.Thick relatively nickel dam 524 is deposited on the silver layer 522 and (for example, makes deposited by electron beam evaporation).Layer 524 can be used as diffusion impervious layer, enters silver layer 522 to reduce diffusion of impurities.Gold layer 526 is deposited on the nickel dam 524 and (for example, uses thermal resistance evaporation).Then between among nitrogen, hydrogen, air or the moulding gas, with 400-600 degree centigrade, LED disk 500 was carried out annealing in process 30 to 300 seconds, to obtain ohmic contact.

Referring to Figure 17, make submount wafer 600 by consecutive deposition (for example, making deposited by electron beam evaporation) al contact layer 604 on p-doped silicon disk 602.Gold layer 608 is deposited (for example, using thermal evaporation) on layer 604, and AuSn binder course 610 is deposited (for example, using thermal evaporation) on layer 608.Between among nitrogen, hydrogen, air or the moulding gas, with 350-500 degree centigrade, LED disk 500 was carried out annealing in process 30 to 300 seconds, to obtain ohmic contact.

By using 0 to the pressure of 0.5Mpa and 200-400 degree centigrade temperature layers 610 of layer 526 and submount wafer 600 to be contacted, disk 500 and 600 combined (for example, utilizing hot mechanical pressing) together.Layer 510 and layer 610 have formed eutectic bond (eutectic bond).Cool off the wafer sandwich of combination then, and from pressing, remove the interlayer of combination.

After combination, raise technology by laser substrate 502 is removed from the structure of combination.Laser lifts technology at (for example) United States Patent (USP) 6,420,242,6,071, and 795 introduce, incorporated by reference at this.In certain embodiments, the laser beam of 248 nanometers pass from substrate 502 shine, near with Sapphire Substrate 502 contact position localized heating n-doping Si:GaN layers 506, the sublayer of decomposing n-doped layer 506.Subsequently, wafer sandwich is heated to fusing point above gallium, by the cross force (for example, using cotton rod) that is applied to Sapphire Substrate 502 it is removed from interlayer at this temperature spot.Then, remove the GaN surface (for example, using the hydrogen chloride acid bath) expose to remove liquid gallium from the surface.Usually, when when the GaN epitaxial layer stack is removed Sapphire Substrate 502, the stress in piling up (because substrate 502 and pile up between the lattice generation that do not match) by removal from pile up.This allows, and stack layer can form warpage or curved shape when being bonded to substrate 502, and is the shape of relatively flat on the exposed surface of n-doped layer 506.When selecting carrier 120 to lift when producing slight crack in the technology at laser preventing, then need to consider thermal coefficient of expansion.In addition, by in step, carrying out the overlapping and iterative process in field basically, can be reduced in laser and lift slight crack in the technology.

Referring to Figure 18, to obtain the expectation thickness of this layer, this thickness will be used in last device (Figure 19) to the exposed surface of n-doping Si:GaN layer 506 etched (for example, using active-ion-etch technology).After etching, the superficial makings 700 that the surface of etched GaN layer 506 is coarse owing to etching has.Can carry out planarization, slimming (for example, adopting chemical-mechanical technology) to obtain the being used for final thickness of layer 506 and to coarse surface 700 less than the root mean square surface smoothness of about 5 nanometers.As an alternative, can keep coarse surface 700 to touch the ejection efficiency that device 100 helps to increase device by introducing a local on-plane surface.With meticulous smooth surface, has improved when light ray during with mode impact surface 700 repeatedly on coarse surface, and it finally impinges upon on the surface 700 with the critical angle less than the Snell law and passes the probability on surface 700.

After etching, be produced on the dielectric function pattern in the n-doped layer 506: the flatness layer 702 of at first on n-Doped GaN layer 506, placing (for example, using a spin coating) material (for example, polymer), and on this flatness layer 702, place (for example, spin coating) barrier layer 704.Then, in n-doped layer 506, create the figure that forms the optical lattice among the LED by nano imprint printing and etch process.At first, the model of the figure that definition is wished is stamped in the barrier layer 704, and is formed on all surface of disk in the mode that a part connects a part, printing out the feature of figure 150, and has reserved the zone of deposit n-contact in subsequent technique.Preferably, in this technical process, the surface of n-doped layer 506 comes down to smooth.For example, can also use printing of X-ray or deep UV printing to create figure in the barrier layer 704.As the replacement of on barrier layer on the disk and barrier layer, creating figure at disk, can be on the surface of layer 506 deposit etching mask in advance.

The layer 704 of needle drawing is used as mask figure is sent to flatness layer 702 (for example, using active-ion-etch technology (reactive-ion etching process)).Flatness layer is used as mask in fact figure is sent to n-doped layer 506.After etching GaN layer 506, remove (for example, using oxygen base active-ion-etch) flatness layer.

After figure is sent to n-doped layer 506, can selectively layer of phosphor material be placed (for example, spin coating) on the patterned surface of n-doped layer 506.In certain embodiments, phosphorus can as one man be coated on the surface of needle drawing (bottom and side coating along the opening of patterned surface do not have emptying aperture in fact).As an alternative, encapsulating material layer can be placed on the surface of n-doped layer 506 of needle drawing (for example, by CVD, sputter, the liquid adhesive that forms in the mode of evaporation subsequently suspends).In certain embodiments, encapsulating material can comprise one or more phosphate materials.In certain embodiments, can compress phosphate material to obtain about 20%, about 15%, about 10%, about 5% or about 2% thickness evenness less than the average thickness of phosphate material.In certain embodiments, the encapsulating material that comprises phosphorus can be coated on the patterned surface equably.

In n-doped layer 506, create after the dielectric function pattern, can cut out each LED tube core from disk.Disk is handled and wafer test in case finish, and separates and makes each LED to carry out packaging and testing.The potential damage that can use the dark oblique angle of side passivation step and/or pre-separation etching step to be reduced in to take place in the disk cutting to electricity and/or the light characteristic of needle drawing LED.Single led size can be the virtually any size that reaches the size of disk itself, but each LED is normally square or rectangle, and its side length of side is between about 0.5 millimeter to 5 millimeters.In order to create tube core, use the light printing technology of standard to be limited to the position of the contact mat on the disk that is used for device is excited, and evaporate (for example, utilizing electron beam evaporation) ohmic contact to the position of hope.

If encapsulated the LED tube core, the light collection is convenient in this encapsulation usually, and the machinery and the environmental protection of tube core also are provided simultaneously.For example, when not using encapsulating material, can on the LED tube core, encapsulate the patterned surface that transparent cover plate comes protective layer 506.The glass powder that use is dissolved in smelting furnace (glassy frit) adheres to cover slip 140 on the strutting piece 142.Use welded top or epoxy resin (for example) to connect the opposed end of strutting piece.Strutting piece usually by nickel plating so that be welded on the gold-plated surface of encapsulation.Can be sure of there is not encapsulating material layer, allow in the Surface L ED100 of needle drawing per unit area higher allow electrical load.The deterioration of encapsulating material is the total inefficacy mechanism of standard LED normally, and can not use encapsulating material layer to avoid.

Because LED is from than cutting out the smooth disk of large tracts of land, the light output of their per unit area can not reduce along with area.Equally, because the cross section of each LED that cuts out from disk can closely encapsulate a lot of separately addressable LED tightly less times greater than the light emitting sheet area of LED in array.If a LED does not work (because big defective),, can not influence the performance of array significantly because each device is closely encapsulated.

Though by the agency of some embodiment, other embodiment also is feasible.

For example, though top some thickness of light-emitting device and the relevant layer introduced, other thickness also is possible.In a word, light-emitting device can have any desired thickness, and each layer in the light-emitting device can have any desired thickness.Usually, the thickness of each layer in multiple layer stack 122 is selected to be increased in the space overlap that light produces the optical mode in zone 130, to be increased in the output variable of the light that produces in the zone 130.The example thickness of some in the light-emitting device layer comprises as follows.In certain embodiments, layer 134 (for example has about at least 100 nanometers, at least about 200 nanometers, at least about 300 nanometers, at least about 400 nanometers, about at least 500 nanometers) and/or about 10 microns (for example, about at the most 5 microns at most, about at the most 3 microns, about at the most 1 micron) thickness.In certain embodiments, layer 128 has the thickness of about at least 10 nanometers (for example, about at least 25 nanometers, about at least 40 nanometers) and/or about 1 micron at most (for example, maximum about 500 nanometers, about 100 nanometers at most).In certain embodiments, layer 126 has the thickness of about at least 10 nanometers are arranged (for example, about at least 50 nanometers, about at least 100 nanometers) and/or about 1 micron at most (for example, about 500 nanometers, about 250 nanometers at most) at most.In certain embodiments, light produces zone 130 and has about at least 10 nanometers are arranged (for example, about at least 25 nanometers, at least about 50 nanometers, at least about 100 nanometers) and/or the maximum thickness of about 500 nanometers (for example, about 250 nanometers, about 10 nanometers at most) at most.

As an example, though introduced light-emitting diode, can use have above-mentioned feature other light-emitting device of (for example, figure, technology).This light-emitting device comprises laser and optical amplifier.

As other example, though introduced the separating layer of current-diffusion layer 132 as n-doped layer 134, in certain embodiments, current-diffusion layer can become one with layer 134 (for example a, part).In such embodiments, current-diffusion layer can be that layer 134 high relatively n-doped portion or symplasm interface are (for example, AlGaN/GaN) to form 2 dimensional electron gas bodies.

In another example,, also can use other semi-conducting material though introduced some semi-conducting material.In a word, operable any semi-conducting material (for example, III-V semi-conducting material, organic semiconducting materials, silicon) can be used in the light-emitting device.The example of other luminescent materials comprises InGaAsP, AlInGaN, AlGaAs, InGaAlP.Luminous organic material comprises such as three-8 hydroxyl Kui aluminum phosphate (Alq ₃) micromolecule, such as poly-[2-methoxyl group-5-(2-ethyl hexyl oxy)-1,4-contraposition styrene/diene] or to the conjugated polymer of phenylacetylene (MEH-PPV).

In another example, though by the agency of larger area LED, LED can also be the LED (for example, the edge is less than the about 300 microns LED of standard) of small size.

In another example, though by the agency of wherein figure be formed with holes, according to the dielectric function that figure spatially changes, described figure can also other modes form.For example, in suitable layer, figure can adopt the mode of continuous vein or discontinuous vein to form.And, under the situation that does not adopt hole or vein, can obtain to have the figure that changes dielectric function.For example, the material with different dielectric function can be patterned on the suitable layer.Can also use the combination of these figures.

In another example, though by the agency of layer 126 form by silver, can also use other material.In certain embodiments, layer 126 is by forming by reverberation generation zone material that produce, that impinge upon the light of about at least 50% on the layer of reflective material, and wherein layer of reflective material is between strutting piece and multiple layer stack.This examples of material comprises distributed bragg reflector stacks and such as the various metals and the alloy of aluminium and aluminium-containing alloy.

In another example, strutting piece 120 can be formed by various materials.The examples of material that forms strutting piece 120 comprises copper, copper tungsten, aluminium nitride, carborundum, beryllium oxide, diamond, TEC and aluminium.

In another example, though by the agency of layer 126 forms by heat-absorbing material, in certain embodiments, light-emitting device can comprise separating layer as heat sink (for example, place layers 126 and carrier 120 between).In such an embodiment, layer 126 can or can't help can be used as the material formation of heat sink.

In another example, though by the agency of except utilizing overall optical to produce the zone, changeable graphics in dielectric function only enters n-doped layer 134 (it can reduce the possibility of surperficial recombination carrier loss in fact), in certain embodiments, changeable graphics in dielectric function (for example can extend beyond the n-doped layer, enter current-diffusion layer 132, light produces zone 130, and/or p-doped layer 128).

In another example, though by the agency of air can be placed on embodiment between surface 110 and the cover slip 140, in certain embodiments, the other materials except air also can be placed on surperficial 110 and cover slip between.Usually, this material has about at least 1 and less than the refractive index of about 1.5 (for example, less than about 1.4, less than about 1.3, less than about 1.2, less than about 1.1).This examples of material comprises the gas of nitrogen, air or some higher thermal conductivity.In these embodiments, can patterned surface 110 or not needle drawing.For example, surface 110 can not needle drawing, but is coarse (that is, have less than any distribution, various sizes and the profile of λ/5 feature).

In certain embodiments, light-emitting device can comprise layer of phosphor material, and this phosphate material is coated on surface 110, cover slip 140 and the strutting piece 142.

In certain embodiments, light-emitting device comprises the cover layer 140 with phosphate material wherein.In these embodiments, surface 110 can needle drawing or not needle drawing.

In the realization of a replacement, the light that is produced zone 130 emissions by light is UV (perhaps purple, indigo plant), and phosphorus layer 180 comprises red phosphorus material (for example, L ₂O ₂S:Eu ³⁺), green phosphate material (for example: ZnS:Cu, Al, Mn), blue phosphor material (for example: (Sr, Ca, Ba, Mg) ₁₀(PO ₄) ₆Cl:Eu ²⁺) mixture.

Claims (20)

1. method of making light-emitting device comprises:

One substrate desquamation that will combine with ground floor;

Wherein, described ground floor forms the part of multiple layer stack, described multiple layer stack comprises that light produces the zone, and described method forms light-emitting device, and the surface of the ground floor in this light-emitting device has the dielectric function that changes according to a figure in the space.

2. method as claimed in claim 1 further is included in and peels off the step of grinding and polishing after the described substrate.

3. method as claimed in claim 1 is wherein peeled off described substrate and is comprised that heating places the binder course between ground floor and the described substrate.

4. method as claimed in claim 3, thus wherein heat at least a portion that described binder course decomposes described binder course.

5. method as claimed in claim 3 wherein heats described binder course and comprises described binder course is exposed to a laser radiation emitted.

6. method as claimed in claim 5 is wherein peeled off described substrate and is comprised and use a laser to lift the technology described substrate that exposes.

7. method as claimed in claim 1 is wherein peeled off described substrate and is caused the surface of ground floor to become smooth basically.

8. method as claimed in claim 1 further is included in described substrate and is stripped from the surface of planarization ground floor afterwards.

9. method as claimed in claim 8, wherein, the surface of planarization ground floor comprises carries out chemical-mechanical polishing to the surface of ground floor.

10. method as claimed in claim 8, wherein the surface of planarization ground floor makes the roughness on surface of ground floor be reduced to greater than λ/5, wherein λ is the wavelength of light that ground floor can be launched.

11. method as claimed in claim 1 further is included in and peels off the described substrate described figure of formation in the surface of ground floor afterwards.

12., wherein form described figure and comprise the nano print technology of using as the method for claim 11.

13. as the method for claim 11, wherein said figure has the feature greater than λ/5, wherein λ is the wavelength of light that ground floor can be launched.

14. method as claimed in claim 1, wherein said ground floor comprise a n-dopant material layer, described multiple layer stack further comprises a p-dopant material layer, and described light produces the zone and places between described p-dopant material layer and the described n-dopant material layer.

15. method as claimed in claim 1, wherein the surface of ground floor has the feature of size less than λ/5, and wherein λ produces the wavelength of light that the zone produces and can send from described light-emitting device through the surface of ground floor by light.

16. method as claimed in claim 1, wherein the figure of Bian Huaing is from by non-periodic pattern, complex periodic pattern and have the ideal lattice constant and the group that constitutes greater than zero the figure that detunes parameter in select.

17. as the method for claim 16, wherein said non-periodic pattern comprises from by the brilliant figure of standard, the non-periodic pattern of selecting in the group that Robinson's figure and Amman figure constitute.

18. as the method for claim 16, wherein said complex periodic pattern comprises the complex periodic pattern of selecting from the group that is made of cellular pattern and Archimedes's figure.

19. method as claimed in claim 1 is included in further that deposit electrically contacts on the ground floor.

20. method as claimed in claim 1 comprises further forming electrically contacting that it is configured to injection current in described light-emitting device.

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