Modeling the diffusion of Be in InGaAs/InGaAsP epitaxial heterostructures under non-equilibrium point defect conditions

Be diffusion from 0.2 mu m Be doped (3 x 10(19) cm(-3)) In0.53Ga0.47As laye r sandwiched between 0.5 mu m undoped In0.73Ga0.27As0.58P0.42 layers, grown by GSMBE has been studied. The samples were subjected to RTA in temperatur e range from 700 degrees C to 900 degrees C with time durations of 10-240 s . SIMS was employed for a quantitative determination of the Be depth profil es. Two kick-out models of substitutional-interstitial diffusion have been considered. To explain the obtained experimental results, the kick-out mode l, involving neutral Be interstitial species and singly positively charged Ga or In self-interstitials is proposed. The built-in electric field, bulk self-interstitial generation/annihilation, the Fermi-level and extended def ect formation effects were taken into account in the simulations. (C) 1999 Elsevier Science B.V. All rights reserved.