Patent ID: 7750396

Claim:
A semiconductor device comprising: a semiconductor substrate; a first dielectric film formed on the semiconductor substrate; a second dielectric film formed on the first dielectric film and having a higher permittivity than the first dielectric film; a gate electrode formed on the second dielectric film, both end portions of the gate electrode in the gate length direction projecting out from the second dielectric film with an eave shape; a third dielectric film formed between the both end portions of the gate electrode projecting out with an eave shape and the semiconductor substrate and having a lower permittivity than the second dielectric film; a source region and a drain region formed in parts of the semiconductor substrate lateral to the gate electrode; and a channel region formed in a part of the semiconductor substrate between the source region and the drain region, wherein both end portions of the first dielectric film and the second dielectric film in the gate length direction are located at more inner positions than the both end portions of the gate electrode in the gate length direction, the first dielectric film is formed so as to completely cover the lower surface of the second dielectric film, the third dielectric film is made of silicon nitride, and an extreme end of the source region located near the channel region and an extreme end of the drain region located near the channel region are located inwardly of both side surfaces of the gate electrode in the gate length direction and located outwardly of both side surfaces of the first dielectric film in the gate length direction.