Molecular Beam Epitaxy of Non-stoichiometric III-V Compounds: Theoretical Modeling and Simulation

Surface dynamics dominate the incorporation and segregation of atoms in the molecular beam epitaxy (MBE) of compound semiconductors. A rate equation model is proposed which includes the presence and dynamics of a physisorbed surface layer containing atoms riding the growth surface. The PA layer dictates the incorporation and concentration of various atomic species, such as As~Qaand As%a in low temperature GaAs MBE and In in InGaAs MBE growth. Additionally, it influences the RHEED oscillations (ROs) behavior. The model results for the dependence of As£aand AsQa concentrations on beam equivalent pressure (BEP) and growth temperature are in good agreement with experimental data. Using the same kinetic model for the tem-poral behavior of the surface, the contribution of the PA layer to the RHEED intensity is computed based on kinematical theory of electron diffraction. The experimental observation of the ROs during growth at high and low temperatures with no ROs in the intermediate temperature range of 300-400°C is in good agreement with our model results. The same model is extended to investigate the segregation of In in InGaA