SEMICONDUCTOR DEVICE

A semiconductor device includes a drift layer, a base layer, a collector layer, gate insulating films, gate electrodes, an emitter region, a first electrode and a second electrode. The base layer is provided on the drift layer. The drift layer is provided between the base layer and the collector layer. The gate insulating films are respectively provided on wall surfaces of trenches penetrating the base layer to reach the drift layer. The gate electrodes are respectively provided on the gate insulating films. The emitter region is provided in a surface layer portion of the base layer, and is in contact with the trenches. The first electrode is electrically coupled with the base layer and the emitter region. The second electrode is electrically coupled with the collector layer. Some gate electrodes are applied with a gate voltage. Other gate electrodes are electrically coupled to the first electrode.