Patent ID: 6049095
Filing Date: 2000-04-11
Classification: H01L

Abstract:
A semiconductor device comprising:an insulation film formed on a semiconductor substrate,a semiconductor layer of a first conductivity type formed on said insulation film,a first impurity region of a second conductivity type formed at a main surface of said semiconductor layer,a second impurity region of the first conductivity type formed at the main surface of said semiconductor layer, and surrounded by said first impurity region,a third impurity region of the first conductivity type formed at the main surface of said semiconductor layer, and spaced apart from said first impurity region,a fourth impurity region of the second conductivity type formed at the main surface of said semiconductor layer, and surrounded by said third impurity region,a fifth impurity region of the second conductivity type electrically connected to said first impurity region, and formed at said semiconductor layer with a predetermined distance from said fourth impurity region at the main surface,a first electrode formed on a surface of said semiconductor layer and said third impurity region sandwiched by said fifth impurity region and said fourth impurity region, with an insulation film thereunder,a second electrode electrically connected to said fourth impurity region, anda third electrode electrically connected to said second impurity region, and electrically connected to said first impurity region at a short-circuit plane,wherein said fifth impurity region includes a plurality of branch-like regions electrically connected to the first impurity region and extending from the first impurity region towards the fourth impurity region, and the leading end portions of the branch-like regions are located apart from each other with no region electrically connecting the leading end portions of the branch-like regions, and the leading end portion of each branch-like region and the fourth impurity region are arranged with a distance therebetween, andwherein a distance between a leading end portion of each said branch-like region and said fourth impurity region is said predetermined distance at said main surface.