Ge Incorporation in GaAs Grown by Molecular Beam Epitaxy: A Thermodynamic Study

The compensation ratio variations with epitaxial conditions, i.e. , substrate temperature, arsenic pressure, were studied for Ge‐doped layers grown by molecular beam epitaxy. To explain the experimental results obtained, a model is proposed based on equilibrium thermodynamics, which includes Ga and As vacancy generation and the reaction of Ge exchange between the two sublattices. Using the thermochemical data available, the theoretical results obtained show qualitative agreement with the compensation ratio variation observed. In addition, the proposed model explains all the reported trends for doping in molecular beam epitaxy using group IV impurities. The study concludes with the major role played by quasi‐equilibrium native‐defect concentration in amphoteric impurity behavior, despite the far from equilibrium growth technique used.