Patent ID: 7872314

Claim:
A semiconductor device comprising: a semiconductor substrate; and an N-channel type MISFET formed on said semiconductor substrate, said N-channel type MISFET comprising: a laminated structure of a gate insulation film and a gate electrode formed on said semiconductor substrate; an N-type source region formed in a surface of said semiconductor substrate; an N-type drain region formed in said surface of said semiconductor substrate; a first sidewall insulation film formed on a side surface of said laminated structure and part of surfaces of said N-type source region and said N-type drain region; and a second sidewall insulation film formed to face the side surface of said laminated structure and part of said surfaces of said N-type source region and said N-type drain region, with said first sidewall insulation film being interposed therebetween, wherein at least said N-type source region and said N-type drain region are implanted with ions, a height of said first sidewall insulation film from said surface of said semiconductor substrate is smaller than a height of said second sidewall insulation film from said surface of said semiconductor substrate, a maximum distance of said first sidewall insulation film from said side surface of said laminated structure is smaller than a maximum distance of said second sidewall insulation film from said side surface of said laminated structure, and a difference between said maximum distance of said second sidewall insulation film and said maximum distance of said first sidewall insulation film is smaller than a difference between said height of said first sidewall insulation film and said height of said second sidewall insulation film.