Temperature-dependent ion mixing and diffusion during sputtering of thin films of CrSi_2 on silicon

Measurements of sputtering yields and composition profiles have been carried out using backscattering spectrometry for samples of CrSi_2 on Si irradiated with 200‐keV Xe ions. When the CrSi_2 layer is thinner than the ion range, the sputtering yield ratio of Si to Cr increases from 3.5 for room‐temperature irradiation to 65 at 290 °C. For a thick sample, the corresponding increase is from 2.4 to 4.0. only. These changes are explained in terms of a rise in the Si surface concentration at 290 °C. The driving force for this process seems to be the establishment of stoichiometric CrSi_2 compound. Transport of Si to the surface is by ion mixing in the thin sample and thermal diffusion through the thick layer