Potential Sputtering of CleanSiO2by Slow Highly Charged Ions

The recently discovered phenomenon of potential sputtering, i.e., the efficient removal of neutral and ionized target particles from certain insulator surfaces due to the potential rather than the kinetic energy of impinging slow highly charged ions, has now also been observed for stoichiometric ${\mathrm{SiO}}_2$ surfaces. Using a sensitive quartz crystal microbalance technique, total sputter yields induced by ${\mathrm{Ar}}^{q+}\left(q\le 14\right)$ and ${\mathrm{Xe}}^{q+}\left(q\le 27\right)$ ions have been determined for LiF and ${\mathrm{SiO}}_2$ surfaces. The primary mechanisms for potential sputtering (defect mediated sputtering) and its considerable practical relevance for highly charged ion-induced surface modification of insulators are discussed.