Location of ion-induced surface Auger decay processes from scattered-ion measurements

The relative yields of different charge states of surface-scattered and -recoiled ions, from amorphous aluminum, with 10-keV N⁺, Ne⁺, and O⁺ incident ions, have been measured as a function of the time which the outgoing particles spend interacting with the surface. During this time the atomic states with 2p shell vacancies from the close binary encounter are converted by the various Auger and resonance processes into ions outside the surface. The characteristic velocities are found to be comparable to or less than those for a silicon surface. A model is proposed in which Auger neutralization inside the surface mainly determines the proportion of atoms with 2p shell vacancies become ionic states outside the surface. {} 1996 The American Physical Society.