Silicon carbide semiconductor device and process for its production

A silicon carbide semiconductor device includes: a semiconductor substrate (1) having a main surface (1a) and a back surface (1b); a drift layer (2) disposed on the main surface (1a); a base region (3a, 3b) disposed on the drift layer (2); a source region (4a, 4b) disposed on the base region (3a, 3b); a surface channel layer (5) disposed on both the drift layer (2) and the base region (3a, 3b) for connection between the source region (4a, 4b) and the drift layer (2); a gate insulating film (7, 7a, 7b) disposed on the surface channel layer (5) and including a high-dielectric-constant film (7a); a gate electrode (8) disposed on the gate insulating film (7, 7a, 7b); a source electrode (10) disposed on the source region (4a, 4b); and a back surface electrode (11) disposed on the back surface (1b).