From Adatom Migration to Chemical Kinetics: Models for MBE, Mombe and MOCVD
AbstractThe application of Monte Carlo simulations to various epitaxial growth methods is examined from the standpoint of incorporating only those kinetics processes that are required to explain experimental data. A basic model for molecular-beam epitaxy (MBE) is first introduced and some of the features that make it suitable for describing atomic-scale processes are pointed out. Extensions of this model for cases where the atomic constituents of the growing surface are delivered in the form of heteroatomic molecules are then considered. The experimental scenarios that is discussed is the homoepitaxy of GaAs(001) using metalorganic molecular-beam epitaxy (MOMBE) with triethylgallium (TEG) and precursors and using MOCVD with trimethylgallium (TMG). For MOMBE, the comparisons between simulations and experiments are based on reflection high-energy electron diffraction intensities, by analogy with comparisons made for MBE, while for metalorganic chemical vapor deposition (MOCVD) the simulations are compared to in situ glancingincidence x-ray scattering measurements. In both of these cases, the inclusion of a second mobile species to represent the precursor together with various rules for the decomposition of this molecule (in terms of rates and local environments) with be shown to provide a useful starting point for explaining the general trends in the experimental data and for further refinements of the model.