X-ray photo-emission and Auger spectra of damage induced by Ar+-ion etching at SiO2surfaces

X-ray photo-emission spectroscopy (XPS) and X-ray-induced Auger spectroscopy have been used to study changes induced by Ar + ions at silica surfaces. No evidence of appreciable surface damage was found for ion energies up to 2 keV. Results of the 6 keV exposed sample showed occurrence of both SiO 2 and SiO x phases. Quantitative XPS analysis was used to monitor modifications in the silica surface stoichiometry as a function of the etching treatment. Whereas Ar + ions of energy up to 2 keV leave the surface composition virtually unchanged, the nO/nSi atomic ratio drops to 1.40 in the 6 keV exposed sample.