The sputtering processes of alkali halides during 6 keV Xe⁺ ion bombardment

Abstract

RbCI, RbBr, RbI and Nat targets have been bombarded with 6 keV Xe⁺ ions. The energy distributions of the sputtered alkali and halogen atoms were examined with a time of flight method. We observed that random collision cascades, thermal spikes and evaporation of decomposed surface material contribute to the sputtering. The binding energies were found to be 3 to 8 times lower than the heat of atomization. The spike temperatures were of the order of 1500 K and a satisfactory agreement with theoretical expectations could be obtained. It is argued that the decomposition of surface material and the subsequent evaporation of alkali and halogen atoms is caused by the same inelastic processes that occur during the sputtering of alkali halides with electrons.