Successful molecular beam epitaxy growth and characterization of (110) GaAs/GaAs and (110) AlGaAs/GaAs

Commonly observed faceting of (110) GaAs films grown by molecular beam epitaxy (MBE) has been analyzed. Facets were studied with respect to MBE growth parameters, the GaAs crystallography, their chemical, electrical, and optical nature, and the kinetics of initial formation. Facets were found to align along the (001) with side planes of (100) and (010). The back planes of the facets were consistently of (111) Ga in nature. The facets were composed of stoichiometric GaAs but resulting films were of poor optical and electrical quality. By exposing an abundance of Ga ledges on the substrate surface, the faceting of the MBE (110) GaAs surface was eliminated. This systematic approach has, for the first time, allowed facet free epitaxy growth of (110) GaAs and (110) AlGaAs/GaAs superlattices. Facet free MBE films were examined by Hall effect, photoluminescence, deep level transient spectroscopy, and transmission electron microscopy. A model of (110) GaAs facet initiation, development, and elimination is presented.