Patent ID: 8217420

Claim:
A power semiconductor device comprising: an IGBT region including a plurality of IGBT units, each of the IGBT units including: a first conductivity-type base layer having a first surface and a second surface opposed to the first surface; a second conductivity-type base layer selectively formed on the first surface of the first conductivity-type base layer; a first conductivity-type emitter layer formed in a surface of the second conductivity-type base layer opposite to the first conductivity-type base layer; a gate electrode formed on the first conductivity-type base layer, the second conductivity-type base layer, and the first conductivity-type emitter layer via a gate insulating film; a first conductivity-type first semiconductor layer formed on the second surface of the first conductivity-type base layer, the first conductivity-type first semiconductor layer having a higher impurity concentration than the first conductivity-type base layer; and a second conductivity-type collector layer formed in a surface of the first conductivity-type first semiconductor layer opposite to the first conductivity-type base layer; a first main electrode formed on a surface of the second conductivity-type collector layer opposite to the first conductivity-type first semiconductor layer; a second main electrode electrically connected onto the first conductivity-type emitter layer and the second conductivity-type base layer and insulated from the gate electrode by an interlayer insulating film; and a first conductivity-type second semiconductor layer extending from the first surface of the first conductivity-type base layer to the first conductivity-type first semiconductor layer around the IGBT region and electrically connected to the first main electrode.