The diffusion of implanted (2.5keV) As was studied by means of medium-energy ion scattering, secondary ion mass spectrometry and 4-point probe techniques. Dopant redistribution, damage recovery and electrical activation by rapid thermal annealing (550 to 975C) was investigated for substrate temperatures of 25, 300 or -120C during implantation. The results revealed an implantation-temperature dependence of the damage structure and As lattice position before annealing. Solid-phase epitaxial re-growth was observed, following annealing (550C, 10s), for all implantation temperatures and resulted in some 60% of the implanted As moving into substitutional positions. Annealing at 875C resulted in a similar As redistribution for all implantation temperatures. Following annealing at 925C, transient-enhanced diffusion was observed in all samples; with more rapid diffusion in the 25C samples than in either the -120 or 300C implantations, which had similar dopant profiles. In the 975C annealing range, similar rates of implant redistribution were observed for the 300 and 25C implants, while diffusion in the -120C sample was reduced. The observations were explained qualitatively in terms of the nature and density of the complex defects which existed in the as-implanted samples.

Implant Temperature-Dependence of Transient-Enhanced Diffusion in Silicon (100) Implanted with Low-Energy Arsenic Ions. S.Whelan, D.G.Armour, J.A.Van den Berg, R.D.Goldberg, S.Zhang, P.Bailey, T.C.Q.Noakes: Materials Science in Semiconductor Processing, 2000, 3[4], 285-90