SEMICONDUCTOR DEVICE AND DC-DC CONVERTER

PROBLEM TO BE SOLVED: To perform a high-speed switching operation by improving a withstand voltage in a semiconductor device.SOLUTION: The semiconductor device includes: a second conductivity-type base region selectively arranged on the first main surface of a first conductivity-type semiconductor layer; a first conductivity-type diffusion region selectively arranged inside the base region; a control electrode arranged via an insulating film, inside a trench which has contact with the diffusion region, penetrates the base region, and reaches the semiconductor layer; at least one second conductivity-type first semiconductor region extended from the first main surface of the semiconductor layer toward the second main surface and arranged by separation from the base region; a second conductivity-type second semiconductor region arranged between the adjacent trenches and by separation from the trenches; a first main electrode electrically connected to the diffusion region, the semiconductor layer, the first semiconductor region, and the second semiconductor region; and a second main electrode electrically connected to the second main surface of the semiconductor layer. The second semiconductor region penetrates the base region and reaches the semiconductor layer.