Patent ID: 7781848

Claim:
A semiconductor device comprising: a semiconductor region of a first conductivity type; a source region of a second conductivity type which is formed in a surface portion of the semiconductor region; a drain region of the second conductivity type which is formed in a surface portion of the semiconductor region and is apart from the source region; a source extension region of the second conductivity type which is formed in a surface portion of the semiconductor region between the source region and the drain region, is in contact with the source region and is apart from the drain region, the source extension region having a depth from a surface of the semiconductor region, which is less than a depth of the source region from the surface of the semiconductor region; a drain extension region of the second conductivity type which is formed in a surface portion of the semiconductor region between the source extension region and the drain region, is in contact with the drain region and is apart from the source extension region, the drain extension region having a depth from the surface of the semiconductor region, which is less than a depth of the drain region from the surface of the semiconductor region; a first gate insulation film which is formed on the semiconductor region between the source extension region and the drain extension region and is formed of a silicon oxide film or a silicon oxynitride film having a nitrogen concentration of 15 atomic % or less; a second gate insulation film which is formed on the first gate insulation film and contains nitrogen at a concentration of between 20 atomic % and 57 atomic %; and a gate electrode which is formed of a semiconductor material of the second conductivity type on the second gate insulation film.