An earlier model for tails in the diffusion profiles of high solute concentrations was developed. The quasi steady-state approach was extended so as to include both vacancies and interstitials at equivalent levels. The I-V recombination was assumed to be close to local equilibrium and to occur via the reaction of defects with defect-impurity pairs. The model predicted characteristic details such as the plateau, kink, and tail which were observed in high solute concentration surface diffusion.

F.F.Morehead, R.F.Lever: Journal of Applied Physics, 1989, 66[11], 5349-52