Silicon carbide semiconductor substrate, method for manufacturing silicon carbide semiconductor substrate, and method for manufacturing silicon carbide semiconductor device where depression supression layer is formed on backside surface of base substrate opposite to main surface on which epitaxial layer is formed

Abstract

A silicon carbide semiconductor substrate includes: a base substrate that has a main surface having an outer diameter of not less than 100 mm and that is made of single-crystal silicon carbide; an epitaxial layer formed on the main surface; and a deformation suppression layer formed on a backside surface of the base substrate opposite to the main surface. In this way, the deformation suppression layer suppresses the substrate from being deformed (for example, warped during high-temperature treatment). This can reduce a risk of causing defects such as crack in the silicon carbide semiconductor substrate during the manufacturing process in performing a method for manufacturing a silicon carbide semiconductor device using the silicon carbide semiconductor substrate.