Patent ID: 7989903

Claim:
A semiconductor device comprising: a first, p-type, semiconductor region; an n-channel insulated-gate transistor which is formed on the first semiconductor region and includes: a first gate insulation film; a first gate electrode formed on the first gate insulation film; and a first drain extension region; a second, n-type, semiconductor region; and a p-channel insulated-gate transistor which is formed on the second semiconductor region and includes: a second gate insulation film; a second gate electrode formed on the second gate insulation film; and a second drain extension region, wherein an overlap capacitance between the second drain extension region and the second gate electrode is greater than an overlap capacitance between the first drain extension region and the first gate electrode, wherein at least one of the first gate insulation film and the second gate insulation film includes: a third gate insulation film which is formed on the first or second semiconductor region and is formed of a silicon oxide film or a silicon oxynitride film having a nitrogen concentration of 15 atomic % or less; and a fourth gate insulation film which is formed on the third gate insulation film and contains nitrogen at a concentration of between 20 atomic % and 57 atomic %.