Patent ID: 6841879

Claim:
A semiconductor device comprising: a semiconductor substrate having a main surface; an insulating film on said semiconductor substrate and an electrode on said insulating film and having opposite first and second side surfaces and a top surface; a first impurity region of a first conductivity type in said semiconductor substrate and at the main surface of said semiconductor substrate, extending substantially from a position immediately under the first side surface of said electrode, away from said electrode, and having a first length on the main surface of said semiconductor substrate; a second impurity region of the first conductivity type in said semiconductor substrate at the main surface of said semiconductor substrate, extending substantially from a position immediately under the second side surface of said electrode, away from said electrode, and having a second length on the main surface of said semiconductor substrate shorter than the first length; a third impurity region of the first conductivity type in said semiconductor substrate and at the main surface of said semiconductor substrate, extending, from a position neighboring said first impurity region, away from said electrode, and having a higher impurity concentration than said first impurity region; a fourth impurity region of the first conductivity type in said semiconductor substrate and at the main surface of said semiconductor substrate, extending, from a position neighboring said second impurity region, away from said electrode and having a higher impurity concentration than said second impurity region; and a metal silicide layer on at least a portion of the top surface of said electrode and surfaces of said third and fourth impurity regions.