Semiconductor device, method for manufacturing same, power module, power conversion device, and rail vehicle

To improve reliability and yield of a power semiconductor device by achieving a stable ohmic contact. In order to solve the above-mentioned problem, this semiconductor device has, in an n - type epitaxial layer formed on a first main surface of an n + type SiC substrate formed of 4H-SiC, a p type body region, an n + type source region formed in the p type body region, and an n + type 3C-SiC region and a p + type potential fixing region, which are formed in the n + type source region. A barrier metal film is formed in contact with the n + type 3C-SiC region and the p + type potential fixing region, and a source wiring electrode is formed on the barrier metal film.