Lightly-doped samples of n-type or p-type material were implanted with low doses of H, B and Si ions, using energies of between 1 and 6MeV. The resultant electrically active point defects were characterized by means of deep-level transient spectroscopy. Several of these defects were found to involve O and/or C; major impurities in as-grown crystalline material. Both interstitial- and vacancy-type defects were observed. In particular, interstitial C was found to migrate at room temperature with a diffusivity of about 10-15cm2/s, and was effectively trapped by interstitial O atoms. The concentration of implantation-induced defects increased linearly with dose but defect production decreased at sufficiently high dose rates. The latter dose rate effect depended upon the ion mass, and could be qualitatively predicted by computer simulation of defect reaction kinetics.

J.Lalita, N.Keskitalo, A.Hallen, C.Jagadish, B.G.Svensson: Nuclear Instruments and Methods in Physics Research B, 1996, 120[1-4], 27-32