The occurrence of Be diffusion during post-growth annealing was studied in epitaxial InGaAs layers which were grown between 2 undoped InGaAs layers. In order to explain the observed concentration profiles and related diffusion mechanisms, a general substitutional-interstitial model was proposed. On one hand, simultaneous diffusion by dissociative and kick-out mechanisms was suggested and, on the other hand, the Fermi-level effect was used to explain changes in the effective diffusion coefficient of Be species as a function of concentration. A concentration-dependent diffusivity was also used to obtain an improved fit to Be diffusion profiles.

S.Koumetz, J.Marcon, K.Ketata, M.Ketata, C.Dubon-Chevallier, P.Launay, J.L.Benchimol: Applied Physics Letters, 1995, 67[15], 2161-3