Kinetics of Interstitial-Substitutional Exchange of Zn, Pt, and Au in Si: Experimental Results and Theoretical Calculations

Abstract

The diffusion behavior of Zn, Pt, and Au in Si is completely described on the basis of interstitial-substitutional exchange mechanisms namely the dissociative and the kick-out diffusion mechanism. Recently, diffusion profiles of Zn in Si obtained after diffusion at temperatures between 870 and 1208 °C were analysed yielding information about equilibrium concentrations of intrinsic point defects involved in the diffusion process. Moreover, analysis of Zn diffusion yields the fraction of Zn on interstitial and substitutional sites and the mass action constants of the underlying diffusion-reaction processes which are presented in the present paper. From the temperature dependence of these quantities the enthalpy difference between interstitial and substitutional Zn and the reaction enthalpies for the diffusion processes were obtained. Total energy calculations for Zn, Pt, and Au on substitutional and tetrahedral interstitial sites were additionally. carried out and compared with experimental result obtained for Zn and estimates for Pt and Au. Finally, given the formation enthalpy of Si self-interstitials determined from theoretical work, reaction energies for the kick-out process are obtained.