Peeling-free tungsten polycide process and its application in DRAM fabrication

The adhesion of tungsten silicide on polysilicon is an often seen problem associated with the applications of tungsten polycide films in device fabrications. This work, correlates the film adhesion to film composition changes in post-deposition thermal treatments. RBS and SIMS are used to explore the film composition and characteristics changes. The silicon diffusion mechanism is illustrated. The silicide peeling phenomena is investigated with a DRAM device vehicle. Based on the results, approaches to prevent silicide peeling are proposed