Effect upon the Sputtering Threshold Due to Accumulation of Projectiles in Target Material

Abstract

In order to quantify the accumulation effect of projectiles in target material for sputtering, sputtering yields of carbon for pure graphite and the projectile retaining carbon target material bombarded by xenon and helium ions are calculated with a Monte Carlo code ACAT. The ACAT results have indicated that the threshold energy for sputtering is reduced due to the accumulation of the xenon atoms in graphite. Meanwhile, the threshold energy for carbon sputtering is not largely influenced by the retained helium atoms in graphite. Mass ratio of the projectile to the target atom is the important factor for the low energy sputtering yield. An empirical formula for sputtering yields for graphite retaining xenon atoms has been proposed.