Patent ID: 7414285

Claim:
A nonvolatile semiconductor memory device comprising: a first insulating film which is provided on a surface of a semiconductor substrate; a charge accumulation layer which is provided on the first insulating film; a second insulating film which is provided above the charge accumulation layer and contains silicon and nitrogen; a third insulating film which is provided on the second insulating film, and is composed of a single-layer insulating film containing oxygen or a plural-layer stacked insulating film at least whose films on a top layer and a bottom layer contain oxygen, relative dielectric constant of the single-layer insulating film and the stacked insulating film being larger than relative dielectric constant of a silicon oxide film; a fourth insulating film which is provided on the third insulating film and contains silicon and nitrogen; a control gate which is provided above the fourth insulating film; and a fifth insulating film which is provided between the charge accumulation layer and the second insulating film or between the fourth insulating film and the control gate, and contains silicon and oxygen.