Silicon carbide semiconductor device

摘要

A semiconductor substrate includes a first conductivity type semiconductor layer and a second conductivity type semiconductor layer thereon. A first conductivity type semiconductor region is formed in a surface portion of the second conductivity type semiconductor layer and is divided into first and second regions. A trench is formed in the semiconductor substrate so as to penetrate the second conductivity type semiconductor layer and to reach the first conductivity type semiconductor layer. The first region is disposed around the trench so that the side surface of the first region is exposed to the trench. The second region is disposed to be distant from the trench and to be adjacent to the first region. A bottom face of the second region is located to a position deeper than that of said first region. As a result, when a high voltage is applied between a source and a drain, it is possible to cause a punch-through phenomenon to occur at the second region earlier than at the first region.