The silicon carbide semiconductor device and process for their preparation

It is an object of the present invention to provide a silicon carbide semiconductor device that reduces the influence of error angle of a silicon carbide substrate on properties of the semiconductor device, and achieves an improved operating stability and a reduced resistance. In a trench gate silicon carbide MOSFET type semiconductor device, which is formed on the silicon carbide semiconductor substrate with the error angle, a doped low-channel region is formed in a well region at a first side wall surface side of the trench, and a doped High Channel region with an effective acceptor concentration which is lower than that of the low-doped channel region is formed in the well region at a second side wall surface side of the trench.