Patent ID: 8227811

Claim:
A semiconductor rectifying device comprising: a semiconductor substrate made of hexagonal first-conductive-type wide bandgap semiconductor; a semiconductor layer made of hexagonal first-conductive-type wide bandgap semiconductor, the semiconductor layer being formed on an upper surface of the semiconductor substrate, the semiconductor layer having an impurity concentration lower than that of the semiconductor substrate; first semiconductor regions made of first-conductive-type wide bandgap semiconductor, the first semiconductor regions being formed at a surface of the semiconductor layer; second semiconductor regions made of second-conductive-type wide bandgap semiconductor, the second semiconductor regions being interposed between the first semiconductor regions; third semiconductor regions made of second-conductive-type wide bandgap semiconductor, at least part of the third semiconductor regions are connected to the second semiconductor regions, the third semiconductor regions being interposed between the first semiconductor regions, the third semiconductor regions having width smaller than that of the second semiconductor regions; a first electrode formed on the first and second semiconductor regions; and a second electrode formed on a lower surface of the semiconductor substrate, wherein, a direction in which a longitudinal direction of the third semiconductor regions are projected onto a (0001) plane of the semiconductor layer has an angle of 90±30 degrees with respect to a <11-20> direction of the semiconductor layer, and a gap between the third semiconductor regions is not lower than 2d×tan 18°, where d is a thickness of the semiconductor layer.