Simulation of post-growth Be diffusion in InGaAsP grown by GSMBE

Be diffusion in InGaAsP quaternary alloys lattice matched to InP by gas sou rce molecular beam epitaxy (GSMBE) was studied using Secondary Ion Mass Spe ctrometry (SIMS). The experimental structures consisted of a 0.2 mu m Be-do ped (3 x 10(19) cm(-3)) In0.73Ga0.27As0.58Po0.42 epilayer sandwiched betwee n two 0.5 mu m undoped In0.73Ga0.27As0.58P0.42 epilayers. The samples were subjected to rapid thermal annealing (RTA) in the temperature range from 70 0 degrees C to 900 degrees C with time durations of 10-240 s. Be diffusion was simulated, in order to obtain the best agreements with experimental pro files, according to two kick-out models: the first model using neutral Be i nterstitials and singly positively charged (Ga, In) self-interstitials, and the second model using singly positively charged Be interstitials and doub ly positively charged Ga, In self-interstitials. Comparison with experiment al data shows that the first kick-out model gives a better description. (C) 1999 Elsevier Science B.V. All rights reserved.