Gradient-corrected density-functional calculations were used to determine the structure, stability, and diffusion of arsenic-interstitial and phosphorus-interstitial pairs in the positive, neutral, and negative charge states. For both cases, the calculations showed that the neutral pair will be dominant under intrinsic conditions while the neutral and negative pairs will both be important in extrinsic n-type materials. The overall diffusion activation energies of neutral Ass-Sii and Ps-Sii pairs were predicted to be 3.75 and 3.43eV, respectively, in good agreement with experimental observations in intrinsic regions.

Interstitial-Mediated Mechanisms of As and P Diffusion in Si - Gradient-Corrected Density-Functional Calculations. S.A.Harrison, T.F.Edgar, G.S.Hwang: Physical Review B, 74[19], 195202 (5pp)