Patent ID: 7651914

Claim:
A manufacturing method of a nonvolatile semiconductor memory device comprising: providing a first insulating film on a surface of a semiconductor substrate; providing a silicon film to be a charge accumulation layer on the first insulating film; providing a fifth insulating film containing silicon and oxygen on the silicon film by performing a surface treatment using a solution having hydrogen peroxide added therein or a solution having ozone added therein to the silicon film; providing a second insulating film containing silicon and nitrogen on the fifth insulating film; providing a third insulating film on the second insulating film, the third insulating film is composed of a single-layer insulating film containing oxygen or multiple-layer stacked insulating film at least whose films on a top layer and a bottom layer contain oxygen, and 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; providing a fourth insulating film containing silicon and nitrogen on the third insulating film; and providing a control gate above the fourth insulating film.