Threshold sputtering effects in a Cu–Au alloy

Threshold sputtering effects in a dilute copper–gold alloy resulting from low‐energy, light ion bombardment have been studied using ion scattering spectroscopy. Preferential removal of Cu occurs at 25 °C when the alloy is bombarded at normal incidence with 150 eV 3He+. The development of a Au enriched surface layer with increasing ion fluence was followed by monitoring the scattered ion energy spectrum during bombardment. The data agree with a model for preferential sputtering in which a Au enriched layer forms with a thickness that is comparable to the range of 150 eV 3He+ in Cu. It therefore appears that preferential sputtering at the alloy surface is accompanied by atomic mixing throughout the volume penetrated by the incident ions.