Free energies, structures, and diffusion of point defects in Si using an empirical potential

The cumulant-expansion and the thermodynamic-integration techniques, along with others, were considered for electrically neutral point-defect free energies of formation and migration. The thermodynamic integration method was found to be best. Free energies, enthalpies, and entropies of both formation and migration were evaluated as a function of temperature using the Tersoff3 potential-energy function for a variety of types of point defects. Equilibrium point-defect populations and diffusion coefficients have been evaluated as a function of temperature. Near the silicon melting temperature, Frenkel-defect formation was simulated to show that no activation barrier exists for point-defect recombination.