Patent ID: 8927368
Filing Date: 2015-01-06
Classification: H01L,Y10S

Abstract:
1. A method for manufacturing a silicon carbide semiconductor device comprising the steps of: preparing a silicon carbide substrate including a first layer that has first conductivity type, a second layer that is provided on said first layer and that has second conductivity type, and a third layer that is provided on said second layer, that is separated from said first layer by said second layer, and that has said first conductivity type; forming a trench in said silicon carbide substrate, said trench having a side wall and a bottom portion, said side wall extending through said third layer and said second layer and reaching said first layer, said bottom portion being formed of said first layer; forming a trench insulating film to cover each of said bottom portion and said side wall; forming a silicon film to fill said trench with said trench insulating film being interposed therebetween; partially etching said silicon film so as to expose a portion of said trench insulating film that covers said second layer on said side wall and so as to leave a portion of said silicon film that is disposed on said bottom portion with said trench insulating film being interposed therebetween; exposing said second layer on said side wall by removing the portion of said trench insulating film that covers said second layer on said side wall, after the step of partially etching said silicon film; forming a bottom insulating film which contacts said trench insulating film covering said bottom portion of said trench by entirely converting said silicon film on said trench insulating film into an oxide film, after the step of exposing said second layer; forming a side wall insulating film to cover said second layer on said side wall, after the step of exposing said second layer; and forming a gate electrode on said side wall with said side wall insulating film being interposed therebetween.