A search for a thermal spike effect in sputtering. I. Temperature dependence of the yield at low-kev, heavy-ion bombardment

Abstract

The temperature dependence of the angular-differential sputtering yield of silver has been studied for low-keV, heavy ion bombardment in order to check whether thermal spikes contribute to sputtering in this energy regime. An oscillating quartz microbalance was used as detector for sputtered particles.

The measurements reported in this work pertain to sputtering of polycrystalline samples bombarded by 8 keV Ar⁺ and Xe⁺ ions at incident angles of 0°-60° and temperatures of 25 to 775 °C. No pronounced increase of the yield with temperature was observed. It is therefore concluded that thermal spikes are either of no significance in this energy range for atomic projectiles or they cannot be affected by the temperature of the bulk lattice. A small (30%) enhancement of the yield was observed after prolonged bombardment at target temperatures higher than about 400°C; this can be associated with the changes in surface morphology observed.