Patent ID: 8878306

Claim:
A semiconductor device comprising: a semiconductor substrate; a first transistor including a first gate insulating film, a first gate electrode on the first gate insulating film, a first diffusion layer in the semiconductor substrate adjacent to the first gate electrode, and a first insulating film above the first diffusion layer; and a second transistor including a second gate insulating film, a second gate electrode on the second gate insulating film, and a second diffusion layer in the semiconductor substrate adjacent to the second gate electrode; wherein the second gate insulating film directly under the second gate electrode has a second thickness less than a first thickness of the first gate insulating film directly under the first gate electrode, and a lowermost portion of an upper surface of the second diffusion layer is lower than a lower surface of the second gate insulating film directly under the second gate electrode, and a distance between a lowermost portion of an upper surface of the first diffusion layer and a lower surface of the first gate insulating film is less than a distance between the lowermost portion of the upper surface of the second diffusion layer and the lower surface of the second gate insulating film.