A computational study of ion-implanted beryllium diffusion in gallium arsenide

The diffusion of implanted beryllium in gallium arsenide at 100 keV for doses of 1 × 1013 and 1 × 1014 cm−2 during post-implant RTA were studied and simulated at temperatures of 700-900 °C for 1-4 min. The observed Be diffusion profiles, obtained by the SIMS technique, can be satisfactorily explained in terms of a “kick-out” model of 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 “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 with proper initial and boundary conditions using the computational algorithms based on finite-difference approximations.