Epitaxial Growth of Al on (NH4)2Sx-Treated GaAs

Abstract
Epitaxial growth of Al film on the (NH4)2S x -treated surface of (100) GaAs was investigated by means of reflection high-energy electron diffraction (RHEED). A single crystal of epitaxial (110) Al film was obtained on the treated surface with heat treatment at 300°C prior to Al deposition, while Al film became polycrystalline without heat treatment. The effect is explained in terms of the alignment of S atoms on GaAs. The (NH4)2S x -treated surface seems to be useful in the wide range of GaAs processes.