Direct Evidence for Tetrahedral Interstitial Er in Si

Abstract

We report on the lattice location of Er in Si using the emission channeling technique. The angular distribution of conversion electrons emitted by the decay chain ${}^{167}\mathrm{Tm}$ $({t}_{1/2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}9.25\phantom{\rule{0ex}{0ex}}\mathrm{d}){\ensuremath{\rightarrow}}^{167m}\mathrm{Er}\phantom{\rule{0ex}{0ex}}(2.27\mathrm{s})$ was monitored with a position-sensitive detector following room temperature implantation and annealing up to 950 \ifmmode^\circ\else\textdegree\fi{}C. Our experiments give direct evidence that Er is stable on tetrahedral interstitial sites in float-zone Si. We also confirm that rare earth atoms strongly interact with oxygen, which finally leads to their incorporation on low-symmetry lattice sites in Czochralski Si.