Characterization of oxide desorption from InSb(001) substrates

Abstract

Thermal desorption of oxide layers from InSb(001) substrates was studied using reflection high energy electron diffraction (RHEED), x-ray photoelectron spectroscopy, Auger electron spectroscopy, and scanning electron spectroscopy. Surfaces of as-loaded substrates prepared using either of two common chemical etchants were composed of oxide layers containing In2O3 and Sb2O5. As the substrate temperature was raised, a multistage desorption process was observed. Most of the Sb2O5 was reduced during the first stage, leaving behind a thin oxide layer consisting predominantly of In2O3. In2O3 was desorbed during the second stage, as the substrate temperature was raised further in the presence of an Sb flux. Indium droplets condensed on the surface before a smooth morphology ensued. We suggest that the reduction of In2O3 produced In droplets which reacted with the supplied Sb flux to form InSb. Annealing produced smooth, stoichiometric surfaces that gave rise to well-defined, Sb-stabilized pseudo-(1×3) RHEED patterns. InSb films grown on such substrates exhibited good structural and electrical properties.