Properties of tungsten silicide film on polycrystalline silicon

Tungsten silicide on polycrystalline Si becomes increasingly important as interconnections and gate electrodes for metal-oxide-semiconductor field-effect transistor(MOSFET) integrated circuits. Annealing behaviors of coevaporatd tungsten silicide on P-doped poly-Si are studied by x-ray diffraction, He +-backscattering, transmission electron microscopy (TEM), and secondary ion mass spectroscopy (SIMS). High-temperature annealing of silicides results in crystallization and homogenization of tungsten silicide as well as phosphorus out-diffusion from the poly-Si. Their effect on device fabrication is also discussed.