Patent ID: 7968941

Claim:
A semiconductor device, comprising: a semiconductor layer; a body layer, formed in a surface of said semiconductor layer, which includes a channel region therein; a first impurity diffusion region formed in the surface of said semiconductor layer and disposed in superposition on said body layer; a gate insulator formed on said semiconductor layer; a gate electrode formed on said semiconductor layer including a portion above the channel region through said gate insulator disposed therebetween; a drift layer, formed on said semiconductor layer; and a second impurity diffusion region formed in the surface of said semiconductor layer and disposed opposite to said first impurity diffusion region, wherein said body layer is disposed such that a boundary surface thereof at an end in a gate-width direction is in contact with an undersurface of said gate insulator, and wherein said gate insulator has a thick film portion thicker than a part above the channel region in a gate-length direction at least in a part where said gate insulator is in contact with the boundary surface of said body layer at the end in a gate-width direction.