The diffusion of implanted Be in GaAs at 100keV for doses of 1013 and 1014/cm2 during post-implant RTA were studied and simulated at 700 to 900C for 60 to 240s. The observed Be diffusion profiles, obtained by the SIMS technique, could be satisfactorily explained in terms of a kick-out model for the substitutional-interstitial diffusion mechanism, involving singly-ionized Be and doubly-ionized Ga interstitial species. The generation of the excess Ga interstitials, according to the so-called plus-one approach, and its annihilation in the local Ga interstitial sink region were taken into account. The corresponding coupled partial differential equations of the relevant diffusion model were solved numerically, under proper initial and boundary conditions, using computational algorithms based upon finite-difference approximations.

A Computational Study of Ion-Implanted Beryllium Diffusion in Gallium Arsenide. S.D.Koumetz, J.C.Pesant, C.Dubois: Computational Materials Science, 2008, 43[4], 902-8