Patent ID: 8581331

Claim:
A nonvolatile semiconductor memory device comprising: a semiconductor region; a first insulating film on the semiconductor region; a charge storage layer on the first insulating film; a second insulating film on the charge storage layer; and a control gate electrode on the second insulating film, wherein the second insulating film includes a bottom layer (A) formed of Hf-oxide, a top layer (C) formed of Hf-oxide, and a middle layer (B) formed of (SiO 2 ) x (Si 3 N 4 ) 1-x (0.75≦x≦1), the middle layer (B) is between the bottom layer (A) and the top layer (C), the charge storage layer is formed of a plurality of layers, and the control gate electrode includes a first layer comprising Ta, and a second layer comprising W, the first layer is contact with the top layer C, and the second layer is contact with the first layer.