Mobility of Hg⁺ and Br⁺ Implanted in Quartz

Abstract

Both Hg⁺ and Br⁺ were implanted in quartz (Si0₂) 7 years ago. The mobilities of the implanted Hg⁺ and Br⁺ at room and higher temperatures are investigated by Rutherford backscattering of 2·1 MeV He²⁺ ions. The results show that both Hg⁺ and Br⁺ are still immobile at room temperature after 7 years. The depth distributions of Hg⁺ agree well with those calculated by the transport of ions in matter program (TRIM'90). However, for the case of Br⁺ the mean projected range is shallower than the TRIM'90 prediction with increasing implantation energy. It is found that 300 keV Hg⁺ and 250 keV Br⁺ are mobile after 6000°C and 5000°C annealing respectively. Both diffusion and evaporation during annealing are observed.