Patent ID: 7446376

Claim:
An insulated gate bipolar transistor, comprising a semiconductor substrate having a top and a bottom surface, a gate insulation film formed on the top surface, said gate insulation film comprising at least one contact opening, said semiconductor substrate comprising an emitter layer of first conductivity type adjoining said bottom surface, a drift region of second conductivity type adjoining said emitter layer, a channel region of first conductivity type with a doping concentration p C formed in the drift region underneath the contact opening and underneath part of the gate insulation film, one or more source regions of second conductivity type disposed in the channel region and delimiting a base contact area; a gate electrode formed on the gate insulation film, a bottom metallization layer formed on the bottom surface, a top metallization layer covering the contact opening and being contacted by one or more source regions, wherein a first base region of first conductivity type with a doping concentration p B1 is disposed in the channel region so that it encompasses the one or more source regions, wherein at least one common boundary line on the top surface is formed by the first base region, the one or more source regions and the channel region on the top surface, wherein the doping concentration p B1 of the first base region is higher than the doping concentration p C of the channel region, wherein a second base region with a doping concentration p B2 of first conductivity type is laterally confined in the semiconductor substrate to a region underneath the base contact area so that it partially overlaps with the channel region and with the first base region, and wherein the doping concentration p B2 of the second base region is higher than the doping concentration p C of the channel region.