Point defect trapping in solid-phase epitaxially grown silicon-antimony alloys

Abstract

Supersaturated silicon alloys produced by antimony implantation followed by solid-phase-epitaxial growth (furnace annealing), contain a supersaturation of interstitials. This is deduced from the observation of a transient, greatly enhanced diffusion of Sb into precipitates upon heating, accompanied by the formation of interstitial loops. In similar alloys produced by liquid-phase-epitaxial regrowth (pulsed laser annealing) much lower diffusion coefficients were obtained and no loops were observed. These observations provide clear evidence for the diffusion of the substitutional Sb dopant by an interstitialcy mechanism. The activation energy of the enhanced diffusion was 1.8±0.2 eV, presumably corresponding to the migration enthalpy of Sb by the interstitialcy mechanism. The loop number density at the end of the transient gave an estimate of the initial interstitial concentration, which allowed the diffusivity of Sb by the interstitialcy mechanism to be estimated.