Patent ID: 8766369

Claim:
A semiconductor device comprising: a semiconductor substrate which includes a first region and a second region; a first impurity layer formed in the semiconductor substrate of the first region and containing a first impurity of a first conductivity type; a second impurity region layer formed in the semiconductor substrate of the second region and containing a second impurity, which has a diffusion constant smaller than a diffusion constant of the first impurity, of the first conductivity type; a first semiconductor layer formed on the first impurity layer; a second semiconductor layer formed on the second impurity layer; a first gate insulating film formed on the first semiconductor layer; a second gate insulating film thinner than the first gate insulating film formed on the second semiconductor layer; a first gate electrode formed on the first gate insulating film; a second gate electrode formed on the second gate insulating film; a first source/drain region of a second conductivity type which is different from the first conductivity type formed in the first semiconductor layer; and a second source/drain region of the second conductivity type formed in the second semiconductor layer.