| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device having excellent charge retention characteristics obtainable by preventing trap electron redistribution in an inter-electrode insulating film, and a method for manufacturing the same.SOLUTION: A nonvolatile semiconductor memory device according to an embodiment comprises a base, a first insulating film, a charge storage layer, an element isolation insulating film, a second insulating film, and a control electrode. A semiconductor layer is formed on a surface of the base. The first insulating film is formed on an active region of the semiconductor layer. The charge storage layer is formed on the first insulating film. The element isolation insulating film is formed so that a top surface of the element isolation insulating film is positioned at a height between a top surface and a bottom surface of the charge storage layer, and isolates a surface layer part of the semiconductor substrate into the active region. The second insulating film is formed so as to cover a level difference composed of the charge storage layer and the element isolation insulating film, and the charge storage layer. The control electrode is formed on the second insulating film. The second insulating film includes a first silicon oxide film and a first silicon nitride film formed on the first silicon oxide film. Nitrogen concentration in the first silicon nitride film is uneven. |
