SUBSTRATE FOR MOUNTING SEMICONDUCTOR ELEMENT

摘要

A substrate for a semiconductor element, particularly, a high-power semiconductor element, having a high thermal conductivity and a coefficient of thermal expansion approximating that of common semiconductor materials. The substrate includes a metal base composed of a W alloy containing Cu in an amount of 5 to 20 wt % with a thermal expansion coefficient of 4.5 to 7.5 x 10<-><6> cm/cm degree C and a thermal conductivity of 0.4 cal/cm sec degree C or more or Mo alloy containing Cu in an amount of 5 to 30 wt % with a thermal expansion coefficient of 5.0 to 8.0 x 10<6> cm/cm degree C and a thermal conductivity of at least 0.38 cal/cm sec degree C. The metal base is coated with an electrically insulating inorganic material to a thickness of 0.1 to 20 mu m.