Experimental investigation of structures of interior interfaces in GaAs

A method for the structural investigation of interior inverted GaAs/AlAs interfaces is presented which combines highly selective etching and subsequent atomic force microscopy. It provides three-dimensional mappings of interior GaAs interfaces on a lateral scale on the order of micrometers with angstrom z resolution. The perfection of this method is demonstrated, which allows the observation of the real interface monolayer island and terrace structure. Potential aluminum residues on the uncovered interfaces are below the detection limit of Auger electron spectroscopy, which is estimated to 16% of aluminum in a single monolayer on a GaAs crystal. The structure of an interior interface can differ significantly from that of a corresponding surface layer after cooling down from the growth temperature. The substantial restructuring of the interface morphology caused by growth interruptions is investigated in detail for metalorganic vapor phase epitaxy. (C) 1999 American Institute of Physics. [S0021-8979(99)02424-X].