Semiconductor device and method of manufacturing semiconductor device

Abstract

A silicon carbide semiconductor device includes a first semiconductor layer of a first conductivity type on a semiconductor substrate of the first conductivity type; a second semiconductor layer of a second conductivity type; a first semiconductor region of the first conductivity type; trenches penetrating the second semiconductor layer and the first semiconductor region, and reaching the first semiconductor layer; gate electrodes on gate insulating films in the trenches; a first base region between the trenches; and second base regions at bottoms of the trenches. The first base region includes a lower region equal in thickness to the second base regions and an upper region on the lower region. The first base region has impurity concentration peaks of local maximum values in a thickness direction. A peak nearest an interface between the upper and lower regions is located at a position furthest from any other peak.