Patent ID: 8492867

Claim:
A semiconductor device comprising: a semiconductor substrate including a substrate, a drift layer of a first conductivity type disposed on a surface of the substrate, and a base layer of a second conductivity type disposed on a surface of the drift layer; and an electric field terminal part, wherein the semiconductor substrate is divided into a cell region in which a semiconductor element is disposed and a peripheral region that surrounds the cell region, the base region has a bottom face located on a same plane throughout the cell region and the peripheral region, a portion of the base region located in the peripheral region provides an electric field relaxing layer, the electric field terminal part is disposed in the peripheral region, the electric field terminal part surrounds the cell region and a portion of the electric field relaxing layer, and the electric field terminal part penetrates the electric field relaxing layer from a surface of the electric field relaxing layer to the drift layer, wherein the electric field relaxing layer reaches a channel forming part of the cell region.