A semiconductor device includes: a semiconductor substrate including a main surface and a back surface opposite to the main surface; a semiconductor layer including a first surface in contact with the main surface of the semiconductor substrate and a second surface opposite to the first surface, and including a gate trench recessed in the second surface; a split gate structure provided in the gate trench; an insulating layer filling the gate trench and covering the second surface of the semiconductor layer; and a trap level region formed in any one of the semiconductor layer and the semiconductor substrate to trap carriers moving from the semiconductor layer.