Patent ID: 8716746

Claim:
A semiconductor device comprising: a semiconductor substrate including a first conductivity-type drift layer and a second conductivity-type base layer disposed on the drift layer, a surface of the drift layer opposite to the base layer defining a first surface of the semiconductor substrate, a surface of the base layer opposite to the drift layer defining a second surface of the semiconductor substrate; a second conductivity-type collector layer disposed adjacent to the second surface of the semiconductor substrate; a first conductivity-type cathode layer disposed adjacent to the second surface of the semiconductor substrate at a same level as the collector layer; and a collector electrode disposed on the collector layer and the cathode layer, wherein a section of the semiconductor substrate including the collector layer with respect to a direction along the first surface constitutes an IGBT cell operating as an IGBT element and a section of the semiconductor substrate including the cathode layer with respect to the direction along the first surface constitutes a diode cell operating as a diode element, wherein the IGBT cell includes: a trench passing through the base layer and reaching the drift layer; a gate insulating film disposed on an inner surface of the trench; a gate electrode disposed on the gate insulating film within the trench; a first conductivity-type emitter region disposed in a surface portion of the base layer, the emitter region contacting a side surface of the trench within the base layer; a second conductivity-type first contact region disposed in the surface portion of the base layer; a first conductivity-type floating layer disposed within the base layer at a location deeper than the emitter region and the first contact region with respect to a depth of the trench, the floating layer separating the base layer into a first portion including the emitter region and the first contact region and a second portion adjacent to the drift layer; and an interlayer insulating film disposed to cover an end of the gate electrode, the diode cell includes a second conductivity-type second contact region disposed in the surface portion of the base layer, the IGBT cell and the diode cell further include an emitter electrode that is electrically connected to the emitter region, the first contact region and the second contact region, and the diode cell further includes: a trench passing through the base layer and reaching the drift layer; a gate insulating film disposed on an inner surface of the trench; and a trench electrode disposed on the gate insulating film within the trench, and the trench electrode is electrically connected to the emitter electrode to provide an emitter-ground structure.