Molecular-beam epitaxial growth mechanisms on the GaAs(100) surface

Abstract

We propose a mechanism for molecular-beam epitaxial growth on GaAs(100) and other III–V(100) surfaces which includes a detailed description of the changes in surface reconstructions throughout the growth cycle. We have previously used the electronic stability criterion which requires all arsenic dangling bonds to be filled and all gallium dangling bonds to be empty to successfully predict static surface reconstructions of III–V surfaces. In the work presented here, we use these same criteria to predict electronically stable intermediates during the growth cycle which are characterized by surface dimers and dimer vacancies. The resulting model proposes specific reconstructed electronically stable intermediates during the complete growth cycle. The model explains the retention of the (2×4) overall reconstruction throughout the cycle, provides at least one mechanism for the cyclical roughness variations observed via reflection high-energy electron diffraction oscillations, and pinpoints certain rate limiting configurations in the process which should lead to further fruitful experimental investigations.