Sputtering Experiments with 1- to 5-keV Ar+ Ions

Abstract

Sputtering yields have been determined with 1- to 5-keV Ar+ ions normally incident upon targets of type 304 stainless steel, three different types of polycrystalline Cu, a wide variety of Cu monocrystals, and monocrystals of Si and Ge. Ejection patterns have been recorded from these targets and from a monocrystal of InSb. The sputtering yield of polycrystalline Cu depends on the source of the metal, apparently due to variations in preferred orientation. The yield from Cu monocrystals is strongly dependent on orientation, the effect becoming more pronounced as the energy is increased. A simple model is presented which accounts for this behavior in terms of the variation with direction of the initial mean free path of the incident ion. The ejection patterns leave little doubt that focusing collision chains are primarily responsible for the transport of momentum to the surfaces of close-packed metals.