Patent ID: 7999347
Filing Date: 2011-08-16
Classification: H01L

Abstract:
1. A semiconductor device, comprising: a semiconductor layer of a first conductivity type; a first main electrode that contacts a surface of a center region in the semiconductor layer; a second main electrode that contacts a reverse surface of the semiconductor layer; an insulation layer that contacts a surface of a surrounding region in the semiconductor layer, the surrounding region surrounding the center region; and a ring-shaped region of a second conductivity type, which is formed in the surface of the semiconductor layer in a manner such that the ring-shaped region extends from an inside to an outside of a boundary between the first main electrode and the insulation layer, and extends along the boundary, wherein a shoulder portion is formed in the ring-shaped region in a manner such that a portion of the shoulder portion that contacts the insulation layer is higher than a portion of the shoulder portion that contacts the first main electrode, and wherein the shoulder portion is formed in the ring-shaped region in a manner such that the shoulder portion is convex toward the first main electrode in a cross-sectional view of the semiconductor layer taken along an axial direction of the ring-shaped region.