Turn-off power semiconductor device

A turn-off power semiconductor device comprising:

• (a) a semiconductor substrate having two oppositely situated anode and cathode principal faces respectively defining an anode surface and a cathode surface, said cathode surface including a cathode metallization and said anode surface including an anode metallization;
• (b) between the anode and cathode surfaces inside the semiconductor substrate, plural active unit cells each including a layer sequence comprising, from the anode surface to the cathode surface, an emitter layer of a first conductivity type, a first base layer of a second conductivity type opposite to the first conductivity type, and a second base layer of the first conductivity type, and a second base layer of the first conductivity type;
• and
• (c) between the anode and the cathode surfaces inside the semiconductor substrate, plural adjacently disposed turn-off unit cells each comprising a cathode contact and an anode contact, said turn-off unit cells connected in parallel by means of said anode and cathode contacts being connected to respective of said anode and cathode metallizations;
• wherein:
• (d) said plural active unit cells are arranged into plural segments, each segment comprising more than two of said plural active unit cells;
• (e) each segment is surrounded at its periphery in a lateral direction by respective peripheral short-circuit regions of the first conductivity type which extract charge from the semiconductor substrate;
• (f) the peripheral short-circuit regions extend from the cathode surface into the semiconductor substrate and are conductively connected to the cathode metallization disposed on the cathode surface;
• (g) the second base layer extends laterally only to one segment and, outside the segments, the first base layer emerges at the cathode surface;
• and
• (h) the peripheral short-circuit regions are embedded in the first base layer.