| 摘要 |
PURPOSE:To reduce a parasitic resistance between a source and a gate of a semiconductor device by inserting a thin layer made of a substance different from an extremely thin N<+> type layer to between an N-type active layer and an N<+> type layer. CONSTITUTION:An undoped AlGaAs (or GaAs) 31 is formed approx. 1mum on a semi-insulating GaAs substrate 30, an N-type GaAs layer 32 is formed thereon, an AlGaAs layer 34 is formed approx. 50Angstrom or lower and an N<+> type GaAs layer 33 is further formed thereon. Conditions that the layer 34 of an inserting layer satisfies are those that, even if ohmic electrodes are formed, no defect occurs, specific contacting resistance is 10<-6> OMEGAcm<2> or lower, only the N<+> type layer is etched at the time of recessing, and the inserting layer can remain all or partly. The thickness of the inserting layer is approx. 10-50Angstrom . In case of GaAsMISFET, the inserting layer which satisfies these conditions is AlGa1-xAs (1>=x>0).
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