Non-volatile semiconductor memory device and method of manufacturing the same

A floating gate type non-volatile semiconductor memory device which is capable of electrically writing, erasing, reading and retaining data, the memory device comprising:

• source/drain regions formed in a semiconductor substrate;
• a first gate insulating layer formed on a channel region located between the source/drain regions;
• a floating gate electrode functioning as a first charge trapping layer and formed on the first gate insulating layer;
• a second gate insulating layer including a first silicon nitride film formed on the first charge trapping layer and a first silicon oxide film formed on the first silicon nitride film;
• a second charge trapping layer formed on the second gate insulating layer, and including an insulating film containing Al and O as major elements, said insulating film having Al vacancy, interstitial O atom, N atom substituting for O atom, or divalent cationic atom substituting for Al atom, said insulating film also having electron unoccupied levels within a range of 2 eV from the valence band maximum of Al2O3;
• a third gate insulating layer including a second silicon oxide film formed on the second charge trapping layer and a second silicon nitride film formed on the second silicon oxide film;
• and
• a controlling electrode formed on the third gate insulating layer.