PREFERENTIAL SPUTTERING OF SILICON FROM METAL SILICIDES AT ELEVATED-TEMPERATURES

It has been shown that at elevated temperatures silicon is preferentia lly sputtered from Ti and Co silicides during low energy Ar ion bombar dment. The Si sputtering yield under these conditions is shown to subs tantially exceed that of pure Si, as well as that it is a function of the ion current density. On the other hand, the sputtering yield of th e metal is found to be substantially smaller than that at lower temper atures under the same conditions. These effects have been studied both experimentally and numerically using the dynamic T-DYN program. it is shown that the increased Si sputtering yield is partly due to the so- called sputter yield amplification effect (which is a purely ballistic effect independent of temperature), while its sustenance with dose is caused by thermal and ion beam induced diffusion and segregation of S i at the surface.