Patent ID: 8350324

Claim:
A semiconductor device comprising: a semiconductor layer; a first conductive type body region disposed in the semiconductor layer; a second conductive type source region disposed in a surface layer portion of the semiconductor layer and configured to be contiguous with the body region; a gate electrode penetrating through the body region and the source region in a layer thickness direction, the gate electrode having a substantially uniform width from a top to a bottom thereof; a trench extending in the semiconductor layer from a surface thereof to penetrate the source region in the layer thickness direction so that a deepest portion thereof is located nearer to a bottom of the semiconductor layer than a deepest portion of the source region, a side face of the trench being inclined with respect to a direction that is perpendicular to the surface of the semiconductor layer such that a distance between the side face of the trench and the gate electrode is larger when measured at the deepest portion of the trench than at the surface of the semiconductor layer, the trench having a substantially conical shape tapered toward a bottom thereof; a first conductive type body contact region disposed in the semiconductor layer to be sandwiched between the body region and the deepest portion of the trench, the first conductive type body contact region having an outer contour that substantially copies an inner face of the deepest portion of the trench such that the outer contour of the first conductive type body contact region is substantially parallel with an inner surface of the deepest portion of the trench; an insulating film laminated on the semiconductor layer to cover the surface of the semiconductor layer; a contact hole penetrating through the insulating film in the layer thickness direction at a position facing the trench so that a side face thereof is continuous with a side face of the trench, the contact hole having a substantially cylindrical shape that has a uniform radius from a bottom to a top thereof; a wiring disposed on the insulating film; and a contact plug disposed so as to fill up the trench and the contact hole to be connected to the wiring; wherein the contact plug is integral with the wiring.