Patent ID: 7772641

Claim:
A power semiconductor device comprising: a composite semiconductor layer having a trench extending along a first direction in a stripe configuration; a gate electrode buried in the trench for controlling a current flowing in the composite semiconductor layer; a gate plug made of a material having higher electrical conductivity than the gate electrode, the gate plug having the stripe configuration and being connected to the gate electrode along the first direction, the composite semiconductor layer including: a first semiconductor layer of a first conductivity type; a second semiconductor layer of a second conductivity type provided partially in an upper face of the first semiconductor layer; a third semiconductor layer of the first conductivity type provided partially on the second semiconductor layer; and a fourth semiconductor layer of the second conductivity type provided on a lower face of the first semiconductor layer; a gate insulating film for insulating the composite semiconductor layer from the gate electrode; an emitter plug connected to the composite semiconductor layer; an interlayer insulating film provided on the composite semiconductor layer, the interlayer insulating film including at least part of the gate plug and at least part of the emitter plug buried therein; a gate pad provided on the interlayer insulating film and connected to the gate plug; and an emitter pad provided coplanar with the gate pad and connected to the emitter plug, the tip of the emitter plug being buried in the composite semiconductor layer so as to reach the second semiconductor layer.