Patent ID: 8796753

Claim:
A nonvolatile semiconductor storage device, comprising: a semiconductor substrate; a tunnel insulating film formed on a channel region; a charge storage layer formed on the tunnel insulating film; an interlayer insulating film formed on the charge storage layer; a control gate formed on the interlayer insulating film; and an insulating film insulating a side wall of the charge storage layer, wherein the charge storage layer comprises: a conductive layer; and an insulating layer, wherein a width of the conductive layer is smaller than a width of the insulating layer, wherein the insulating film comprises: a portion insulating a side wall of the insulating layer; and a portion insulating a side wall of the conductive layer and a surface of the insulating layer at a side of the conductive layer, and wherein the portion insulating the side wall of the insulating layer and the portion insulating the side wall of the conductive layer and the surface of the insulating layer at the side of the conductive layer comprise the same material.