Patent ID: 7754614

Claim:
A method for fabricating a nonvolatile memory device, comprising: providing a substrate; forming a tunnel insulating layer and an overlying first conductive layer in the substrate in sequence; forming a trench through the overlying first conductive layer and the tunnel insulating layer, wherein a portion of the substrate is exposed from the trench; forming a first insulating layer in the trench; forming a second insulating layer on sidewalls of the first insulating layer, wherein the first insulating layer on a bottom portion of the trench is exposed; conformably forming a third insulating layer in the trench, covering the first insulating layer on the bottom of the trench and the second insulating layer on the sidewalls of the trench, wherein a thickness of the third insulating layer on the sidewalls is thinner than that of on the bottom of the trench; and forming a control gate on the third insulating layer in the trench.