SEMICONDUCTOR DEVICE

A semiconductor device, allowing easy hole extraction, including a semiconductor substrate having drift and base regions; and transistor and diode portions, in which trench portions and mesa portions are formed, is provided. The transistor portion includes emitter and contact regions above the base region and exposed to an upper surface of the semiconductor substrate. The emitter region has a higher concentration than the drift region. The contact region has a higher concentration than the base region. The mesa portions include boundary mesa portion(s) at a boundary between the transistor and diode portions. The trench portions include dummy trench portion(s) provided adjacent to a trench portion adjacent to the boundary mesa portion(s) and provided on the transistor portion side relative to the trench portion adjacent to the boundary mesa portion(s). The boundary mesa portion(s) include a base boundary mesa portion in which the base region is exposed to the upper surface.