Saturation, exchange and retention of implanted D/H ions in fused silica

Elastic recoil detection techniques have been used to measure hydrogen isotope profiles in fused silica implanted with 20 keV H and/or D ions. Saturation is obtained for both H and D implantations at a concentration of 2.2 x 1021 ions/cm3. H and D exchanges are observed for saturated samples subsequently implanted with a different H isotope. A previously developed local mixing model of H-trapping has been extended to include retrapping and beam-induced detrapping for application to these studies. This theoretical analysis provides a good fit to the H/D saturation and isotope exchange behavior. Isochronal annealing shows that both H and D are released in a single stage centered about 5500C