A close relationship between Be surface segregation and diffusion, in molecular beam epitaxial GaAs layers which were heavily doped with Be, was analyzed within the framework of a thermodynamic approach to segregation effects. Good agreement between the theoretical and experimental results suggested that the main cause of extremely fast Be in-diffusion in Be-doped GaAs, and the deterioration of its surface morphology and luminescence properties, was Be surface segregation. This resulted in near-surface solid-phase layer enrichment with Be, as compared with bulk Be-doped GaAs. The effect of growth parameters (excess As pressure, substrate temperature, growth rate) and dopant level upon the likelihood of Be segregation layer formation was considered.

S.V.Ivanov, P.S.Kopev, N.N.Ledentsov: Journal of Crystal Growth, 1991, 108[3-4], 661-9