US Patent 7510925 Method of manufacturing semiconductor device, and semiconductor device

A method of manufacturing a semiconductor device includes: the first step of forming a gate electrode over a silicon substrate, with a gate insulating film; and the second step of digging down a surface layer of the silicon substrate by etching conducted with the gate electrode as a mask. The method of manufacturing the semiconductor device further includes the third step of epitaxially growing, on the surface of the dug-down portion of the silicon substrate, a mixed crystal layer including silicon and atoms different in lattice constant from silicon so that the mixed crystal layer contains an impurity with such a concentration gradient that the impurity concentration increases along the direction from the silicon substrate side toward the surface of the mixed crystal layer.