The dopant sites of B and As in Si were investigated by using ion channeling combined with nuclear reaction analysis and particle-induced X-ray emission. Boron-implanted Si at an energy of 10keV with a dose of 5 x 1014/cm2 (low dose) or 5 x 1015/cm2 (high dose) were annealed (800C, 100min or 1000C, 10s). Arsenic-implanted samples at an energy of 20keV were also prepared. The electrical activation efficiencies of these samples were estimated by using secondary ion mass spectrometry and spreading resistance profiling. It was found that the activation efficiencies were almost the same as the substitutional fractions in the B implanted samples while the As implanted samples have considerably smaller activation efficiencies in spite of large substitutional fractions. This suggested that inactive B clusters mainly consist of interstitial B atoms and that As clusters contain a large fraction of substitutional As atoms.

Activation and Dopant Sites of Ultra-Shallow Implanted Boron and Arsenic in Silicon. H.Kobayashi, I.Nomachi, S.Kusanagi, F.Nishiyama: Nuclear Instruments and Methods in Physics Research B, 2002, 190[1-4], 547-51