Patent ID: 8704290

Claim:
A nonvolatile semiconductor memory device comprising: a semiconductor substrate; and a memory cell; wherein the memory cell includes: a lower insulating film that is disposed on the semiconductor substrate; a charge storage film that is disposed on the lower insulating film; an upper insulating film that is disposed on the charge storage film; and a control gate that is disposed on the upper insulating film; wherein the upper insulating film includes: a first insulting film; a second insulating film that is disposed on the first insulating film; and a third insulating film that is disposed on the second insulating film; wherein the second insulating film has a trap level density larger than that of the third insulating film; wherein a thickness of the first insulating film is thinner than that of the third insulating film; and wherein the second insulating film includes at least one film selected from a group consisting of: an oxide film of Ti, Y, Zr, or Hf; a nitride film of Ti, Y, Zr, or Hf; and an oxynitride film of Ti, Y, Zr, or Hf.