Growth of Si-doped GaAs(110) thin films by molecular beam epitaxy; Si site occupation and the role of arsenic

We have studied the relationship between the surface morphology, Si doping behavior, and arsenic incorporation kinetics for GaAs(110) thin films grown on singular substrates by molecular beam epitaxy. To obtain films with good surface morphology, homoepitaxial growth requires low substrate temperatures and high As:Ga flux ratios. Under these conditions, the Si-doped layers exhibit n-type behavior. Growth at higher temperatures and lower As:Ga flux ratios produces films with a poorer morphology, the n-type layers become increasingly compensated, and p-type layers are eventually formed. This growth-related site switching behavior and corresponding variation in surface morphology can be attributed to a low arsenic surface population, a consequence of the small and temperature-dependent arsenic incorporation coefficient for growth on GaAs(110).