The formation of silicides in Mo-W Bilayer films on si substrates: A marker experiment

Use is made of the metallurgical similarity between Mo and W, and of their different atomic weights to study the diffusive formation of MoSi2 and WSi2. Thin film bilayers of Mo and W were deposited via e-beam evaporation upon Si single crystal substrates and annealed in an inert atmosphere at temperatures up to 1000‡C. The annealed samples were analysed by means of Rutherford backscattering and x-ray diffraction. The results indicate that Si is the dominant diffusing species. Observations on the formation of WSi2 are consistent with a process dominated by grain boundary diffusion through the W film.