Patent ID: 8415765
Filing Date: 2013-04-09
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate having a first conductive type layer; a first diffusion region which has the first conductive type and is formed in the first conductive type layer; a second diffusion region which has a second conductive type and an area larger than an area of the first diffusion region and overlaps the first diffusion region; and a PN junction formed at an interface between the first and the second diffusion regions, wherein the second diffusion region includes a ring shaped structure, a lower step portion on a surface of the first conductive type layer is formed such that the PN junction is deeper than a bottom of the ring shaped structure, the second diffusion region includes a first portion and a second portion, said second portion comprising the ring shaped structure, and an upper step portion is formed by an upper surface of the first portion and the second portion.