Patent ID: 8963198
Filing Date: 2015-02-24
Classification: H01L

Abstract:
1. A semiconductor device conducting current between a first electrode formed on a first main surface of a semiconductor substrate and a second electrode formed on a second main surface of the semiconductor substrate, the semiconductor device comprising: the semiconductor substrate having said first main surface and said second main surface opposite to each other; a first region of a first conductivity type formed in said first main surface of said semiconductor substrate to extend from said first main surface to a first depth; a second region of a second conductivity type having a predetermined impurity concentration, having a planar pattern including a corner, and formed from a surface of a predetermined region in said first region to a second depth shallower than said first depth; a third region of the second conductivity type circumferentially surrounding said second region so that said third region is spaced from said second region, and formed from a surface of said first region to a third depth; the first electrode formed to be electrically connected to said second region; the second electrode formed to contact said second main surface of said semiconductor substrate, and said corner of said second region has a low-impurity-concentration region at a distance across the planar pattern from an inner peripheral end of the planar pattern in a direction substantially orthogonal to a direction of the tangent of the curve at the corner towards the outer peripheral end of the planar pattern, said low-impurity-concentration region having an effective impurity concentration that is lower than the predetermined impurity concentration of the second region away from the corner and at a same distance across the planar pattern as measured from the inner peripheral end in a direction substantially perpendicular to the inner peripheral end.