Temperature-dependent energy thresholds for ion-stimulated defect formation in solids: Effects of ion mass and adsorbate-substrate pairing

Recent simulations and experiments have indicated that solid temperature affects the dynamics of defect formation when the energies of bombarding ions fall below about 100 eV. The physical picture formulated for this phenomenon predicts that ion mass should exert only a weak influence on the threshold energy for defect formation. The present work experimentally confirms that prediction through mesoscale surface diffusion measurements of Ge on Si(1 1 1) as a marker for ion-induced defect behavior. Furthermore, comparisons between the results and those already obtained for In on Si(1 1 1) and Ge(1 1 1) show that the magnitude of the variation in threshold energy with temperature (∼0.1 eV/K) is largely independent of the adsorbate-substrate pairing. The present results give further evidence for the existence of a broad class of temperature-dependent ion-induced defect formation processes.