In an insulated gate field effect semiconductor device, the gate electrode formed on the gate insulating film includes the first and second semiconductor layers as a double layer. An impurity for providing one conductivity type is not contained in first semiconductor layer which is in contact with a...http://www.google.de/patents/US6001712?utm_source=gb-gplus-sharePatent US6001712 - Insulated gate field effect semiconductor device and forming method thereof
