Patent ID: 7176097

Claim:
A process of fabricating a semiconductor device comprising: forming a semiconductor substrate of a first conductivity type, the semiconductor substrate having a surface; forming a gate oxide film and a gate electrode on the surface of the semiconductor substrate; forming a sidewall on both sides of the gate electrode; forming a surface covering film on exposed portions of the surface of the semiconductor substrate; forming a source and a drain beneath the surface covering film by introducing a dopant of a second conductivity type into the semiconductor substrate through the surface covering film, wherein the source and the drain have a first depth from the surface of the semiconductor substrate; removing the sidewalls so as to expose the surface of the semiconductor substrate near the gate electrode; and forming a source side impurity layer and a drain side impurity layer by introducing a dopant of the first conductivity type into the semiconductor substrate through the surface covering film and into the exposed surface of the semiconductor substrate near the gate electrode, wherein the source side impurity layer extends from inside the source at a second depth that is shallower than the first depth, to directly underneath the gate electrode at a third depth that is equal to or deeper than the first depth, and wherein the drain side impurity layer extends from the drain at the second depth to directly underneath the gate electrode at the third depth.