Metallic impurity gettering to defects remaining in the R P/2 region of MeV-ion implanted and annealed silicon

Abstract

Damage has been observed in MeV-ion-implanted Si away from the projected ion range, R P, mainly around R P/2, after annealing at temperatures between 700 and 1000°C. The most suitable way to detect this damage is to decorate it with metals and to measure the metal distribution. The formation and disappearance of the R P/2 damage has been investigated by Cu gettering in Si +-ion implanted Si versus temperature and time of the annealing cycle. It is believed that an excess of vacancies around R P/2 getter metal impurities. By means of positron annihilation spectroscopy no vacancy defects have been detected. In contrast, XTEM investigation reveals small (20–30 nm) interstitial loops in the R P/2 region. The creation of these loops is triggered by interstitials injected during the ion milling procedure used for TEM specimen preparation. The ion bombardment of Si gives rise to self-interstitials that may modify the existing interstitial clusters to bigger agglomerates observable by XTEM.