Patent ID: 6867454

Claim:
A power semiconductor devices comprising: a base layer of a first conductivity type; a base layer of a second conductivity type selectively formed on one surface of said base layer of the first conductivity type; an emitter layer of the first conductivity type selectively formed on the surface of said base layer of the second conductivity type; a collector layer selectively formed on one of the one surface and another surface of said base layer of the first conductivity type; a first main electrode formed on said collector layer; a second main electrode formed on said emitter layer and on said base layer of the second conductivity type; a gate insulating film formed on and directly contacting a surface of said base layer of the second conductivity type that lies between said emitter layer and said base layer of the first conductivity type, said gate insulating film including a first insulating portion and a second insulating portion; and a gate electrode formed above said first and second insulating portions, wherein a capacitance of a capacitor formed of the second insulating portion is smaller than a capacitance of a capacitor formed of the first insulating portion.