Patent ID: 6894348

Claim:
A semiconductor device including: a semiconductor substrate having a main surface; a semiconductor layer of a first conductive type which is formed on the main surface of said semiconductor substrate; a first buried impurity region of the first conductive type formed between said semiconductor layer and said semiconductor substrate; a second buried impurity region of a second conductive type positioned between said first buried impurity region and said semiconductor layer alone a line normal to said main surface; a first impurity region of the second conductive type which is formed in the surface of said semiconductor layer and which is electrically connected to said second buried impurity region; a second impurity region of the first conductive type which is formed in the surface or inside of said semiconductor layer located in a region above said second buried impurity region; and a semiconductor element which includes said first impurity region and said second impurity region and which has a switching function formed on the surface of said semiconductor layer, wherein the withstanding voltage is secured by a depletion layer extending from an interface between said second buried impurity region and said semiconductor layer under the condition where said semiconductor element is turned OFF; and said second buried impurity region includes a first gap part wherein said second buried impurity region is disconnected, said gap part of the second buried impurity region positioned directly beneath said second impurity region.