Patent ID: 7045867

Claim:
A semiconductor device including an MOS transistor comprising: a semiconductor substrate; a gate insulating film selectively disposed on said semiconductor substrate; a gate electrode selectively disposed on said gate insulating film; and a spacer insulating film disposed on a side surface of said gate electrode, wherein said gate insulating film includes a first part corresponding to a central portion of a lower part of said gate electrode and a second part corresponding to an edge portion of the lower part of said gate electrode, said second part has a contoured shape widening vertically so as to increase its thickness from a portion for engagement with said first part, a contoured shape in a state that said spacer insulating film engages said second part of said gate insulating film is in a continuous form of at least an inclination having a first angle corresponding to a tilt angle of a side lower part of said gate electrode and an inclination having a second angle with respect to a main surface of said semiconductor substrate on an upper side of said second part of said gate insulating film, said first angle is greater than said second angle, and the side surface of said gate electrode has a contoured shape curved in a continuous form such that an upper main surface of said gate electrode is wider than a lower main surface.