Experimental investigation of structures of interior interfaces in GaAs

A method for the structural investigation of interior inverted GaAs/AlAs in terfaces is presented which combines highly selective etching and subsequen t atomic force microscopy. It provides three-dimensional mappings of interi or GaAs interfaces on a lateral scale on the order of micrometers with angs trom z resolution. The perfection of this method is demonstrated, which all ows the observation of the real interface monolayer island and terrace stru cture. Potential aluminum residues on the uncovered interfaces are below th e 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 i nterior interface can differ significantly from that of a corresponding sur face 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 Amer ican Institute of Physics. [S0021-8979(99)02424-X].