The diffusion of Be during rapid thermal annealing was studied in heavily-doped structures which had been grown by means of molecular beam epitaxy. Secondary ion mass spectrometry measurements showed that, in p/p+ structures, the Be diffusion was reduced by increasing the As4/Ga flux ratio. However, no effect was observed in p/p+/p structures. Moreover, the Be concentration profiles which were measured after annealing (770 or 850C, 30s) indicated that Be redistribution was almost independent of the annealing temperature. These results were explained in terms of a substitutional interstitial diffusion mechanism.

Influence of the As/Ga Flux Ratio on the Diffusion of Be in MBE GaAs Layers. R.Mosca, S.Franchi, P.Frigeri, E.Gombia, A.Carnera, M.Peroni: Materials Science and Engineering B, 2001, 80[1-3], 32-5