Sputtering of PtSi

Abstract

The sputtering of PtSi by Ar ions of 10 to 160 keV has been studied by Rutherford backscattering techniques with depth resolutions of 200 Å at normal incidence and 40 Å at extreme glancing angles. The surface layers of the sputtered samples become Pt enriched over depths ranging from 100 to 1600 Å. For a given Ar energy, the Pt enrichment extends approximately over a constant depth and the enrichment increases with increasing Ar dose until steady state is reached. The steady-state composition ratio of Pt to Si at the surface is ∼2.0 for all energies. The sputtering yields of Si before steady state are found to be larger than those of Pt, consistent with Pt enrichment. A phenomenological model, based on preferential ejection of Si from the surface and enhanced diffusion over the range of Ar, explains the present data.