Patent ID: 9608074
Date: 2017-03-28
CPC Classifications: H01L

Claim:
1. A silicon carbide semiconductor device, comprising: a silicon carbide substrate having a first main surface and a second main surface opposite to the first main surface, and having a trench formed in the second main surface; a gate electrode being provided in the trench; and a drain electrode being provided in contact with the first main surface, the silicon carbide substrate including: a first conductivity type region constituting the first main surface and having a first conductivity type; a body region being provided on the first conductivity type region and having a second conductivity type which is different from the first conductivity type; a source region being provided on the body region so as to be separated apart from the first conductivity type region, constituting the second main surface, and having the first conductivity type; and a first second conductivity type region being surrounded by the first conductivity type region and having the second conductivity type, the trench being formed of a side wall surface penetrating through the source region and the body region to reach the first conductivity type region, and a bottom portion being located in the first conductivity type region, the side wall surface having a first side wall surface and a second side wall surface facing each other when viewed in a cross section, an impurity concentration of the first second conductivity type region being lower than an impurity concentration of the first conductivity type region, when viewed in a cross section, and it is provided that a contact point at which a boundary surface between the first conductivity type region and the body region is in contact with the first side wall surface is a first contact point, and that a contact point at which a boundary surface between the first conductivity type region and the body region is in contact with the second side wall surface is a second contact point, the first second conductivity type region being provided so as to face a region between the first contact point and the second contact point and be separated from the first main surface, wherein the first conductivity type region includes: a silicon carbide single-crystal substrate constituting the first main surface, having a third main surface opposite to the first main surface, and having a first impurity concentration; and a drift region being provided between the third main surface of the silicon carbide single-crystal substrate and the body region and having a second impurity concentration which is lower than the first impurity concentration, the first second conductivity type region being in direct physical contact with the silicon carbide single-crystal substrate.