The formation of Frenkel pairs, and the diffusion of a self-interstitial atom in silicon crystals at normal and high (hydrostatic) pressures, was modelled using quantum-chemical methods. It was shown that, in a silicon crystal, the most stable configuration of a self-interstitial atom in the neutral charge state (I0) was the split configuration, <110>. The tetrahedral configuration was not stable; an interstitial atom being shifted from position, T, to a new position, T1, over a distance of 0.2Å. The hexagonal configuration was not stable in the NDDO approximation. The split <110> interstitial configuration remained the more stable configuration under hydrostatic pressures (<80kbar). The activation barriers for the diffusion of self-interstitial atoms in silicon crystals were deduced to be: Ea (<110> → T1) = 0.59eV, Ea (T1 → neighbouring T1) = 0.1eV and Ea (T1 → <110>) = 0.23eV. The hydrostatic pressure (<80kbar) increased the activation barrier to the diffusion of self-interstitial atoms in silicon crystals. The energies of formation of a separate Frenkel pair, a self-interstitial atom and a vacancy were determined. It was demonstrated that the hydrostatic pressure decreased the energy for the formation of Frenkel pairs.

Formation of Frenkel Pairs and Diffusion of Self-Interstitial in Si under Normal and Hydrostatic Pressure: Quantum Chemical Simulation. V.Gusakov, V.Belko, N.Dorozhkin: Physica B, 2009, 404[23-24], 4558-60