| 摘要 |
PROBLEM TO BE SOLVED: To suppress the generation of parasitic capacitances and parasitic resistances and to improve high frequency characteristics by specifying the sheet carrier density, at an interface between a silicon substrate and a compound semiconductor layer. SOLUTION: An AlGaAs buffer layer 12 is grown epitaxially on a silicon substrate 11, and a GaAs activated layer 13 is similarly grown epitaxially thereon. During the growth, the layer 12 is intentionally made into a p-type, thereby forming an interface conductive layer 15 in which p-type carriers are compensated for by silicon atoms diffused from the substrate 11. The sheet carrier density of the layer 15 is set at 6×10<12> (cm<-2> ) or lower. As a result, the generation of electric lines of forces between an electrode for a device formed on the compound semiconductor layer and the layer 15 is suppressed, so that the parasitic capacitances and parasitic resistances can be reduced down to a practically negligible degree, and high frequency characteristics can be improved. |
