Patent ID: 7102182

Claim:
A semiconductor device comprising: a first conductive layer of a first conductivity type, a first conductivity type of drain layer formed so as to be laminated on a surface of the first conductive layer, a second conductivity type of second conductive layer of an opposite type from the first conductivity type formed so as to be laminated on a surface of the drain layer, a first conductivity type of source region formed over a range extending from a surface of the second conductive layer to a predetermined depth, a first trench formed so as to reach the drain layer by opening the source region, a second trench formed by opening the source region, a gate insulating film formed on a surface of the first trench, a gate electrode film formed on an inner surface of the gate insulating film, a source electrode film formed at least on a surface of the second trench, and a second conductivity type of buried diffusion region formed within the second conductive layer, exposed on a bottom surface of the second trench, and to a width that is equal to or narrower than a width of the opening of the second trench, wherein the second trench is formed to have an indentation in its bottom surface.