Patent ID: 7429771

Claim:
A semiconductor device comprising: a semiconductor layer of a first conductivity type; a gate insulating film formed on the semiconductor layer; a gate electrode formed on the gate insulating film; insulating sidewalls formed on side surfaces of the gate electrode; diffused source and drain layers of a second conductivity type formed in regions of the semiconductor layer located outside the sidewalls, respectively, diffused extension layers of the second conductivity type formed in regions of the semiconductor layer located below the sides of the gate electrode and between the diffused source and drain layers, respectively; and diffused pocket layers of the first conductivity type formed in regions of the semiconductor layer located below the diffused extension layers, respectively, wherein insides of the diffused source and drain layers are formed with impurity implanted regions of the first conductivity type having a lower impurity concentration than the diffused source and drain layers, and the impurity concentration of the impurity implanted region is higher than that of the diffused pocket layer, and the impurity concentration is higher in the region outside the sidewall than in the region below the sidewall.