Ion-stimulated desorption of positive halogen ions

Abstract

The ejection of ${\mathrm{F}}^{+}$ ions from fluorinated silicon by ${\mathrm{Ar}}^{+}$ or $\mathrm{O}_{2}^{}{}_{}{}^{+}$ impact at 2-10 keV is shown to result from noncollisional processes which follow core-hole creation by the primary ion impact. The ejection mechanism is shown to be closely similar to electron-stimulated desorption, and can be explained using the model of Knotek and Feibelman. ${\mathrm{Cl}}^{+}$ ejection from chlorinated aluminum appears to result from a similar mechanism, whereas ${\mathrm{O}}^{+}$ ejection from oxygen-sputtered silicon appears to be purely collisional. The latter observation is shown to be consistent with the Knotek-Feibelman model.