Patent ID: 9748393
Date: 2017-08-29
CPC Classifications: H01L

Claim:
1. A silicon carbide semiconductor device, comprising: an epitaxial layer of a first conductivity type formed on a silicon carbide semiconductor substrate of the first conductivity type; a trench partially formed in a surface layer of said epitaxial layer; a well layer of a second conductivity type formed along side surfaces and a bottom surface of said trench; a source region of the first conductivity type formed in a surface layer of said well layer on the bottom surface of said trench; a gate insulating film that is formed along the side surfaces of said trench and has one end formed so as to reach said source region; a gate electrode formed along the top of said trench, extending downward onto the side surfaces of said trench, and formed on said gate insulating film; a source electrode formed over said source region; and a drain electrode formed on a back surface of said silicon carbide semiconductor substrate, wherein the one end of said well layer is formed so as to reach a trench non-forming region in which said trench is not formed in the surface layer of said epitaxial layer, said gate insulating film is also formed on said well layer in said trench non-forming region, and said gate insulating film has a thickness of a portion formed on said well layer in said trench non-forming region greater than a thickness of a portion formed along the side surfaces of said trench.