Abstract: A semiconductor device comprises a semiconductor substrate; a semiconductor layer provided on the surface of the semiconductor substrate; a base layer provided on the surface of the semiconductor layer; a source layer provided on the surface of the base layer; a trench formed to pass through the source layer, the base layer, and the semiconductor layer from the surface of the source layer, and reaching the semiconductor substrate; a gate electrode provided from the source layer to at least the semiconductor layer within the trench; and an insulator provided between the gate electrode and the base layer so as to fill in the inside of the trench below the gate electrode, the insulator insulating the gate electrode from the base layer, and generating a potential distribution from the gate electrode toward the semiconductor substrate when a voltage is applied to the gate electrode.

Abstract: A semiconductor device comprises a drain region formed on the reverse side of a semiconductor substrate, a base region formed on the drain region and having parts partially exposed at plural positions on a principal plane of the substrate, a source region which has one plane in contact with the base region and the other plane exposed on the principal plane of the substrate, a gate insulating film formed only on a wall of a trench, which is formed in the substrate to reach the drain region, a gate electrode formed so as to be embedded in the trench and a top surface thereof is situated above the junction plane of the source and base regions and at a position lower than the principal plane of the substrate, and an insulating film embedded above the gate electrode in the trench.