A model for surface layer composition changes in sputtered alloys and compounds

摘要

Under the assumption that extracted beam energy is quickly shared among secondary cascade members of all masses, we present a model which accounts quantitatively for recently observed equilibrium surface enrichments in heavy atoms following ion bombardment of alloys and compounds. Assuming strong radiationhyphen;driven diffusion, effects of which are directly observed, and given the time required to reach equilibrium, we can calculate the thickness Dgr;xof the enriched layer. Alternatively, knowing Dgr;x, a calculation of the equilibration time constant is possible.