Ion-stimulated desorption of positive halogen ions

The ejection of F+ ions from fluorinated silicon by Ar+ or O2+ 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. Cl+ ejection from chlorinated aluminum appears to result from a similar mechanism, whereas O+ ejection from oxygen-sputtered silicon appears to be purely collisional. The latter observation is shown to be consistent with the Knotek-Feibelman model.