Patent ID: 7732821

Claim:
A silicon carbide semiconductor device comprising: a substrate of a first conduction type made of silicon carbide; a drift layer of said first conduction type made of silicon carbide, said drift layer being less doped than said substrate; a cell portion constituted by a part of said substrate and a part of said drift layer, said cell portion including semiconductor elements; a circumferential portion constituted by another part of said substrate and another part of said drift layer, said circumferential portion being formed so as to surround said cell portion; and a RESURF layer of a second conduction type formed in a surface portion of said drift layer so as to be located in said circumferential portion; wherein said RESURF layer is constituted by a first RESURF layer having a first impurity concentration, and a second RESURF layer having a second impurity concentration lower than said first impurity concentration, said second RESURF layer being in contact with an outer circumference of said first RESURF layer and extending to a circumference of said cell portion, and said second RESURF layer covering corners of said first RESURF layer.