Surface Dehomogenization of Binary Alloys during Evaporation and Ion Sputtering

Abstract

A theory is presented for dehomogenization of the surface concentration in binary alloys during evaporation and ion sputtering processes when diffusion is the only mixing process in the alloy phase. The theory is based on the mass balance of the components between the alloy and the gas phases, taking into account the interface displacement due to the evaporation or sputtering loss. Surface dehomogenization in binary alloys of particular geometries is predicted and described in terms of the initial concentration, volatility or sputtering yield, diffusivity, and time. It is shown that the present theory, quantitatively or qualitatively, accounts for the surface dehomogenization behaviors reported in available experimental studies.