Patent ID: 7816706

Claim:
Power semiconductor device with a semiconductor substrate and a cathode metallization being formed on a cathode side and an anode metallization being formed on an anode side opposite the cathode side, said semiconductor substrate comprising a four-layer structure with layers of different conductivity types, said four-layer structure defining an inner structure of a thyristor, which can be turned-off via a gate electrode, and said four-layer structure comprising an outer cathode region of a first conductivity type contacting the cathode metallization, a first base layer of the second conductivity type contacting the cathode region on a side opposite the cathode metallization, a second base layer of the first conductivity type contacting the first base layer on a side opposite the outer cathode region, and an outer anode layer of second conductivity type contacting the anode metallization, said gate electrode being arranged on the cathode side and electrically contacting said first base layer, the first base layer comprising a cathode base region and at least one gate base region, said cathode base region being arranged adjacent to the cathode region on the side opposite the cathode metallization and contacting at least a central area of the cathode region, said at least one gate base region being disposed adjacent to the second base layer and bordering on the cathode base region, said at least one gate base region having the same nominal doping density as the cathode base region in at least one first depth, the first depth being given as a perpendicular distance from the side of the cathode region, which is opposite the cathode metallization, said at least one gate base region electrically contacting the gate electrode, and said at least one gate base region having at least one of the following features: a higher doping density than the cathode base region in at least one second depth, the second depth being greater than said first depth, and a greater depth than the cathode base region.