Semiconductor device and method of manufacturing same

Abstract

A semiconductor device includes an active section for a main current flow and a breakdown withstanding section for breakdown voltage. An external peripheral portion surrounds the active section on one major surface of an n-type semiconductor substrate. The breakdown withstanding section has a ring-shaped semiconductor protrusion, with a rectangular planar pattern including a curved section in each of four corners thereof, as a guard ring. The ring-shaped semiconductor protrusion has a p-type region therein, is sandwiched between a plurality of concavities deeper than the p-type region, and has an electrically conductive film across an insulator film on the surface thereof. Because of this, it is possible to manufacture at low cost a breakdown withstanding structure with which a high breakdown voltage is obtained in a narrow width, wherein there is little drop in breakdown voltage, even when there are variations in a patterning process of a field oxide film.

Dependencies are inferred from the claim text.