Patent ID: 7238576

Claim:
A semiconductor device including a power semiconductor element, the power semiconductor element comprising: a drain layer of a first conductivity type; drift layers of first and second conductivity types provided on the drain layer of the first conductivity type; an insulating film provided between the drift layers of the first and second conductivity types and contacting the drift layers; a first base layer of the second conductivity type provided on a surface of the drift layer of the first conductivity type; a source layer of the first conductivity type selectively provided on a surface of the first base layer of the second conductivity type; a gate insulating film provided on the first base layer of the second conductivity type between the source layer of the first conductivity type and the drift layer of the first conductivity type; a gate electrode provided on the gate insulating film; a second base layer of the second conductivity type provided on a surface of the drift layer of the second conductivity type; a first main electrode provided on the drain layer of the first conductivity type; and a second main electrode provided on the source layer of the first conductivity type, the first base layer of the second conductivity type and the second base layer of the second conductivity type.