Method of forming ono stacked films and DCS tungsten silicide gate to improve polycide gate performance for flash memory devices

摘要

In one embodiment, the present invention relates to a method of forming a flash memory cell, involving the steps of forming a tunnel oxide on a substrate; forming a first polysilicon layer over the tunnel oxide; forming an insulating layer over the first polysilicon layer, the insulating layer comprising a first oxide layer over the first polysilicon layer, a nitride layer over the first oxide layer, and a second oxide layer over the nitride layer; forming a second polysilicon layer over the insulating layer; forming a tungsten silicide layer over the second polysilicon layer by chemical vapor deposition using WF6 and SiH2Cl2; etching at least the first polysilicon layer, the second polysilicon layer, the insulating layer, and the tungsten silicide layer thereby defining at least one stacked gate structure; and forming a source region and a drain region in the substrate, thereby forming at least one memory cell.