SILICON CARBIDE SEMICONDUCTOR DEVICE AND PROCESS FOR PRODUCING THE SAME

摘要

This invention provides a silicon carbide semiconductor device having excellent operating properties and a process for producing the same. An enlarged terrace face is formed by Si film covering annealing on the surface of an initially grown layer (11) provided on a 4H-SiC substrate (10). A newly grown layer (21) is then epitaxially grown on the initially grown layer (11). A 3C-SiC part (21a), which is a polytype stable at low temperatures, is grown on the enlarged terrace face, and a 4H-SiC part (21b) is grown on the other region. The 3C-SiC part (21a) is selectively removed while allowing the 4H-SiC part (21b) to remain unremoved to form a trench (Tr). An UMOSFET gate electrode (27) is formed within the trench (Tr). The channel region in UMOSFET can be regulated as a low-dimensional number face, and a silicon carbide semiconductor device having a high level of channel mobility and excellent operating properties can be realized.