Patent ID: 8552506

Claim:
A semiconductor device comprising: a semiconductor substrate; a first isolation insulating film isolating a first region from a second region in the semiconductor substrate; a second isolation insulating film isolating a third region from a fourth region in the semiconductor substrate; first impurity regions formed in the first region, the second region, and the fourth region, the first impurity regions including an impurity of a first conductivity type and having a first depth; a second impurity region formed in the third region, the second impurity region including an impurity of a second conductivity type and having a second depth deeper than the first depth; a third impurity region formed in the third region, the third impurity region including an impurity of the second conductivity type and having a third depth shallower than the second depth; a first transistor formed in the third region, the first transistor including first source/drain regions of the first conductivity type; and a second transistor formed in the fourth region, the second transistor having second source/drain regions of the second conductivity type.