Semiconductor device

A semiconductor device comprising:

• a first MIS transistor of a first conductivity type including a first gate electrode formed on a first active region of a semiconductor substrate with a first gate insulating film interposed therebetween;
• a second MIS transistor of the first conductivity type including a second gate electrode which is formed on a second active region of the semiconductor substrate with a second gate insulating film interposed therebetween, and has a shorter gate length than the first gate electrode;
• and
• a third MIS transistor of the first conductivity type including a third gate electrode which is formed on a third active region of the semiconductor substrate with a third gate insulating film interposed therebetween, and has a shorter gate length than the second gate electrode, wherein
• the first gate insulating film is formed of a first silicon oxide film and a first high-k insulating film provided on the first silicon oxide film,
• the second gate insulating film is formed of a second silicon oxide film and a second high-k insulating film provided on the second silicon oxide film,
• the third gate insulating film is formed of a third silicon oxide film and a third high-k insulating film provided on the third silicon oxide film, and
• the second silicon oxide film has a substantially same thickness as the first silicon oxide film and a greater thickness than the third silicon oxide film.