Nonvolatile semiconductor memory device and method of fabricating the same

A method of fabricating a nonvolatile semiconductor memory device, comprising:

• forming a first insulation layer on a semiconductor substrate;
• forming a charge storage layer on the first insulation layer;
• forming a second insulation layer on the charge storage layer;
• and
• forming a control electrode on the second gate insulating film, wherein
• the step of forming the second insulation layer includes forming a first silicon nitride film on the charge storage layer, forming a first silicon oxide film on the first silicon nitride film, forming an intermediate insulating film on the first silicon oxide film, the intermediate insulating film having a higher relative permittivity than a silicon nitride film, forming a second silicon oxide film on the intermediate insulating film, and forming a second silicon nitride film on the second silicon oxide film;
• and
• in the first and/or second silicon oxide film forming step, the first and/or second silicon oxide film is formed so as to have a charge trap layer.

A method of fabricating a nonvolatile semiconductor memory device, comprising:

• forming a first insulation layer on a semiconductor substrate;
• forming a charge storage layer on the first insulation layer;
• forming a second insulation layer on the charge storage layer;
• and
• forming a control electrode on the second gate insulating film, wherein
• in the second insulation layer forming step, a first silicon oxide film added with nitride is formed on the charge storage layer, an intermediate insulating film is formed on the first silicon oxide film, the intermediate insulating film having a relative permittivity of not less than 7, and a second silicon oxide film is formed on the intermediate insulating film, the silicon oxide film being formed by an atomic layer deposition (ALD) method.