Molecular-beam-epitaxy GaAs regrowth with clean interfaces by arsenic passivation

Abstract

Clean interfaces between GaAs layers grown by molecular-beam epitaxy (MBE) have been achieved by deposition of arsenic on the surface of the first layer grown, before removing it from the vacuum. Secondary ion mass spectroscopy, deep level transient spectroscopy, and capacitance-voltage carrier profiling show that this arsenic passivation procedure results in no measurable impurity incorporation, no deep levels, and no perturbation of carrier profiles in either n-type or p-type GaAs growth/regrowth interfaces after exposure to air. This is in contrast to growth over nonpassivated etched surfaces which showed large perturbations in free carrier profiles, deep level densities, and impurity incorporation at the interface. This demonstrates that nearly ideal growth/regrowth interfaces are achievable in MBE if impurity incorporation and nonstoichiometry are controlled.