Papers Published

1. Taylor, W.J. and Gosele, U.M. and Tan, T.Y., Precipitate strain relief via point defect interaction: models for SiO₂ in silicon, Mater. Chem. Phys. (Switzerland), vol. 34 no. 2 (1993), pp. 166 - 74 [0254-0584(93)90208-4] .
   (last updated on 2007/04/10)

   Abstract:
   Precipitation in the solid state is often accompanied by a volume mismatch, creating strain which inhibits precipitation. For the SiO₂/Si system, this strain, if unrelieved, is large enough to prevent precipitation altogether. The strain is usually assumed to be relieved via emission or absorption of point defects. The authors suggest a model in which only one species of point defect is involved, and the emission/absorption relieves the strain only partially. They generate a Gibbs free energy equation in two variables, and by monitoring the atom movements during precipitation, are able to derive two relationships: an expression for the critical radius and, more importantly, a direct correlation between strain and point defect supersaturations. They use this approach to study three systems: SiO₂ strain relief via interstitial emission, vacancy absorption and carbon absorption. Finally, the importance of the strain/supersaturation relationship is emphasized by noting its impact upon nucleation rates. Even small point defect supersaturations can eliminate nucleation, and must therefore be considered carefully in studies of precipitation

   Keywords:
   free energy;interstitials;nucleation;precipitation;silicon;silicon compounds;vacancies (crystal);