Influence of the As/Ga flux ratio on diffusion of Be in MBE GaAs layers

Beryllium (Be) diffusion after rapid thermal annealing experiments is studied in heavily doped GaAs structures grown by MBE. SIMS measurements show that in p/p+ structures, Be diffusion is reduced by increasing the As4/Ga flux ratios. In contrast, no effect is observed in p/p+/p structures. Furthermore, Be concentration profiles measured after annealing experiments performed at 770 and 850°C for 30 s indicate that Be redistribution is almost independent of the annealing temperature. These results are discussed in terms of a substitutional interstitial diffusion mechanism.