Interdiffusion of thin chromium and gold films deposited on silicon

The backscattering technique was used to study the interdiffusion process of Cr and Au films deposited on Si substrates. The results indicate that Au diffuses in Cr with an effective diffusion coefficient D = const. * exp(-0.68/kT). The activation energy is consistent with a diffusion process that occurs preferentially through grain boundaries. The high value of the diffusion coefficient justifies the presence of Au at the Cr-Si interface after a low-temperature short-time heat treatment. At temperature > 370°C (the eutectic point of the Si-Au system) and after a longenough heat treatment, the Au is completely mixed with Si.