SILICON CARBIDE SUBSTRATE, SUBSTRATE HAVING EPITAXIAL LAYER ATTACHED THERETO, SEMICONDUCTOR DEVICE, AND PROCESS FOR PRODUCTION OF SILICON CARBIDE SUBSTRATE

摘要

Disclosed are: a silicon carbide substrate having reduced on-resistance; a substrate having an epitaxial layer attached thereto; a semiconductor device; and a process for producing a silicon carbide substrate. The silicon carbide substrate (10) has a main surface, and comprises an SiC single crystal substrate (1) which is formed on at least a part of the main surface and a base member (20) which is so arranged as to surround the SiC single crystal substrate (1). The base member (20) comprises a boundary region (11) and a base region (12). The boundary region (11) is adjacent to the SiC single crystal substrate (1) in the direction along the main surface, and has a grain boundary therein. The base region (12) is adjacent to the SiC single crystal substrate (1) in a direction that is vertical to the main surface, and has higher impurity concentration than that in the SiC single crystal substrate (1).