Effects of ion bombardment on Na and Cl motion in SiO2 thin films

The effects of light and heavy ion bombardment on Na and Cl motion in SiO2 thin films have been studied using proton-induced characteristic x-ray (PIX) and Rutherford backscattering (RBS) techniques. Results show that both Na and Cl atoms may be trapped in the oxides by implantation damage. Release does not occur under ionizing irradiation (proton bombardment). Partial release or motion does occur after annealing to 700°C or by further heavy ion bombardments. Na motion is consistent with the movement of single Na⁺ ions in the oxide. In contrast, the movement of Cl atoms appears to be dominated by enhanced Cl diffusion or by motion of positive Cl-defect complexes whenever heavy ion bombardment damage is introduced.