Theory and experiment of step bunching on misoriented GaAs(001) during metalorganic vapor-phase epitaxy

We present experiments and an accompanying theory for the growth modes during metalorganic vapor-phase epitaxy on vicinal GaAs(001). Our theory is based on a model that takes account of deposition, diffusion, and dissociation of molecular precursors, and the diffusion and step incorporation of atoms released by the precursors. The experimental conditions for island nucleation and growth, step flow, and step bunching are reproduced by this model, with the step bunching instability caused by the difference in molecular dissociation from above and below step edges. (C) 2008 American Institute of Physics.