Patent ID: 7659576

Claim:
A semiconductor device comprising: a collector layer of a first general conductivity type; a drift layer of a second general conductivity type disposed on a front surface of the collector layer; a base layer of the first general conductivity type disposed on the drift layer; a first trench penetrating through the base layer so as to reach the drift layer a second trench penetrating through the base layer so as to reach the drift layer; a gate insulation film disposed on an inner wall of each of the first and second trenches; a gate electrode disposed in each of the first and second trenches so as to cover the gate insulation film; an emitter region of the second general conductivity type formed, for each of the first and second trenches, in the base layer and adjacent a corresponding trench; an emitter electrode connected to the emitter regions; and a collector electrode disposed on a back surface of the collector layer and comprising branching portions penetrating through the collector layer, wherein one of the branching portions is disposed under the base layer between the first trench and the second trench, and none of the branching portions is disposed under the first trench or the second trench.