Method of forming gate of flash memory device

摘要

A method of forming a gate of a flash memory device, including the steps of sequentially forming a tunnel oxide film, a first polysilicon layer for a floating gate, a dielectric layer, a second polysilicon layer for a control gate, a tungsten silicide film, and a hard mask film on a semiconductor substrate; etching the hard mask film, the tungsten silicide film, the second polysilicon layer, and a part of the dielectric layer to expose the first polysilicon layer; and etching the exposed first polysilicon layer and the tunnel oxide film to form a gate, wherein during the etch process of the first polysilicon layer, sidewalls of the first polysilicon layer forming the gate are etched to a predetermined width, thereby increasing a gate width ratio between the first polysilicon layer and the second polysilicon layer.