Patent ID: 7635892
Filing Date: 2009-12-22
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate; a first main electrode provided on a first main surface of said semiconductor substrate; a second main electrode provided on a second main surface of said semiconductor substrate, wherein a main current flows in a thickness direction of said semiconductor substrate; a trench that extends from the first main surface of said semiconductor substrate towards the second main surface; a gate insulating film covering an inner surface of said trench; a gate electrode buried in said trench and surrounded by said gate insulating film, wherein said semiconductor substrate has at least one recess formed in said second main surface and therefore said semiconductor substrate at least has a first region having a first thickness and a second region having a second thickness that is thinner than said first thickness, said second region corresponds to a region where said at least one recess is formed, said second main electrode is provided in said at least one recess, and said second thickness is set at such a thickness as to keep a breakdown voltage of said semiconductor device; and a semiconductor region provided in a surface of said semiconductor substrate in a bottom of said at least one recess and directly contacting the second main electrode, said semiconductor region having a higher impurity concentration than said semiconductor substrate, wherein said semiconductor region has a conductivity type opposite to that of said semiconductor substrate.