Patent ID: 7737494

Claim:
A semiconductor device comprising: a semiconductor layer with an impurity of a first conductivity type diffused therein; a local insulating layer formed in the semiconductor layer; a drain layer formed in the semiconductor layer located on one side of the local insulating layer with an impurity of a second conductivity type opposite to the first conductivity type being diffused therein; a source layer formed in the semiconductor layer separated from the other side of the local insulating layer with the second conductivity type impurity being diffused therein; a gate electrode formed over the semiconductor layer extending from over the local insulating layer to the source layer; a low-concentration diffusion layer formed in the semiconductor layer located below the drain layer, the local insulating layer and the gate electrode with the second conductivity type impurity being diffused therein in a concentration lower than the drain layer; a first gate insulating film formed between the gate electrode and the semiconductor layer and extending from an end on the source layer side, of the gate electrode to the local insulating layer without reaching the local insulating layer; a second gate insulating film formed between the gate electrode and the semiconductor layer and extending from an end on the other side of the local insulating layer to the first gate insulating film, said second gate insulating film being connected to the first gate insulating film and being thicker than the first gate insulating film and thinner than one-half of the thickness of the local insulating layer; a pullout layer formed on a surface of the semiconductor layer adjacent to the source layer, with a high concentration of the first conductivity type impurity; and a body diffusion layer formed in the semiconductor layer, the body diffusion layer being spaced away from the low-concentration diffusion layer, surrounding the source layer and the pullout layer, and having a concentration of the first conductivity type impurity higher than that of the semiconductor layer and lower than that of the pullout layer.