Sputtering of SicGe₁₋c nanospheres

Abstract

It is known that sputter yields of elemental materials depend on the target curvature. Here we explore to what extent this effect is modified for alloy targets using both Monte Carlo and molecular dynamics simulations. For the exemplary case of amorphous SicGe1−c spheres, we find that, in the limit of small curvatures, the curvature dependence of the sputter preferentiality is negligible. This finding can be explained by a natural extension of the existing analytical theory of curvature-dependent sputtering for elemental materials. For large curvatures, however, the sputter preferentiality strongly depends on curvature. In this case, molecular-dynamics simulations also predict strong spike effects which increase the sputter yields. Sputter yield amplification-an increase in partial sputter yield with decreasing concentration of the element-occurs for Si-rich alloys.