MÖSSBAUER STUDIES ON DAMAGE SITES OF ISOTOPE-SEPARATOR-IMPLANTED IMPURITY ATOMS IN SILICON

Abstract

Using the 24-keV Mossbauer y radiation of llgSn, different damage sites in silicon have been studied. The Mossbauer level was populated from the radioactive decay of 1lgmTe. Radiation damage was created by isotope-separator implantation of the radioactive-source nuclei. The implantation behaviour and the occupation of damage sites are different for implantations of Te or of Sb and Sn. While Sb or Sn predominantly end on substitutional sites, Te is distributed over substitutional, interstitial, and damage sites. Annealing experiments utilizing the decay chain 1lgmTe + 119Sb + 9Sn reveal different annealing properties for Te and Sb at the same damage sites. Te-damage agglomerates in silicon formed by the implantation of Te are found to be very stable. The same agglomerates containing Sb (from the radioactive decay of Te) anneal between 400 and 600 C. A large influence of the oxygen content of the host crystal on the formation of the damage agglomerates was found. This is suggested to be due to an indirect mechanism of the trapping of vacancies by oxygen atoms.