Abstract
The altered layer produced by sputtering SiO2 with Ar+ , Ne+ and He+ ions of 70-500 eV energy is studied by AES in conditions avoiding electron beam damage. The understoechiometric layer is characterized by an attenuation of the O KVV Auger peak and by the appearance of additional SiOx (82 eV) and Si (89 eV) peaks in the Si LVV spectrum. The dependence of this damage upon ion mass and ion energy gives information on the mechanism of ion-surface interaction. At medium energy (500 eV), the change in surface composition is compatible with a collisional sputtering model. At lower energies (80-250 eV), He+ interacts quite differently from Ar+ and Ne+ , suggesting the onset of inelastic processes like Auger neutralization