Neutral copper cluster sputtering yields: Ne + Ar + and Xe + bombardment

Abstract

The sputtering of neutral metal clusters was investigated by measuring relative sputtering yields of copper clusters ejected from polycrystalline copper under 3.9 keV bombardment by Ne +, Ar + and Xe + ions at normal incidence. The yields of clusters from Ne 4 bombardment were lower than those from Ar + bombardment, and yields from Ar + bombardment were lower than those from Xe + bombardment. The sputtering yield ratios Ne +/Ar + and Xe +/Ar + were measured to be 0.56 and 1.08. The size distribution of the sputtered clusters can be fit by a power law dependence with exponents of −8.1, −8.2 and −6.2 for Ne +, Ar + and Xe +, respectively. The similarity of the exponents of the Ne + and AI + power law fits indicates that the sputtering yields for these two primary ions are similar, while that for Xe + is substantially higher, in contrast to the sputtering yield ratio data. The difference between the two measurements can be explained by assuming a systematic uncertainty in the sputtering yield ratio measurements that makes the measured ratios lower than the true values. Assuming a value at the high end of the experimental Ne + sputtering yield range, the exponents of the power law fits exhibit a linear dependence on the total sputtering yield.