PREFERENTIAL SPUTTERING OF OXYGEN FROM SIO2 BY LOW-ENERGY ION-BEAM AND NEUTRAL BEAM BOMBARDMENT

Rutherford backscattering and Auger-electron spectroscopy measurements reveal that low-energy (500 eV) neutral Ne-degrees beam bombardment on a SiO2 surface does not cause preferential sputtering of oxygen, whereas Ne+ ion beam bombardment of the same energy causes significant preferential sputtering. The results strongly suggest that the ionic charge plays the dominant role in the preferential sputtering of oxygen from SiO2. In addition, neutral-beam bombardment modifies the SiO2 surface to be resistant to reduction by the subsequent ion beam bombardment. It is argued that neutral-beam bombardment produces densified SiO2.