Sputtering of Au and Al2O3 surfaces by slow highly charged ions

A quartz crystal microbalance technique was used for measuring total sputtering yields for polycrystalline Au and Al2O3 under impact of slow (100-1500 eV) multiply charged Ar and Xe ions. Up to the highest charge states investigated (Xe25+), the sputter yield for the Au target remains independent on the projectile charge state and can be well described by kinetic sputtering only. For Al2O3, on the contrary, a dramatic increase in total sputtering yield with increasing projectile charge state was found, showing that in this case potential sputtering (PS), i.e., sputtering due to the potential energy of the projectile, clearly dominates over kinetically induced sputtering. Results can be explained within the defect-mediated desorption model of PS