Patent ID: 7582933

Claim:
A semiconductor device comprising: a substrate; a semiconductor layer formed on the substrate; a gate insulating film formed on the semiconductor layer; a gate electrode formed in a portion of the area directly above said semiconductor layer on the gate insulating film; and an electrode-protecting insulating film formed on said gate insulating film and said gate electrode; wherein a surface layer portion of said electrode-protecting insulating film is etched away after the electrode-protecting insulating film is formed, wherein a film thickness of a portion other than an area directly under said gate electrode of said gate insulating film is smaller than a film thickness of a portion positioned in an area directly under said gate electrode, and wherein a ratio (B/A) has a value between 0.01 to 0.65, where A is the film thickness of the portion positioned in the area directly under said gate electrode of said gate insulating film, and B is the difference between the film thickness of the portion positioned in the area directly under the gate electrode and the film thickness of the portion other than said area directly under the gate electrode.