THERMAL-DECOMPOSITION OF TRIETHYLGALLIUM ON GAAS(100) IN THE PRESENCE OF AL AND IN

The interaction of triethylgallium (TEG) with the Ga-stabilised GaAs(100) surface in the presence of In and Al has been investigated using AES, HREELS and TDS techniques. Detailed information on the surface chemistry of TEG on clean GaAs is already available and this work is directed towards examining the influence of Al and In, with a view to understanding a variety of effects involved in the epitaxial growth of Ga(Al,In)As alloys by chemical beam epitaxy. Al is shown to greatly increase the saturation coverage of TEG on the surface, and to suppress the desorption of TEG and diethylgallium (DEG). Etching of the surface Al by TEG is observed, resulting in the formation of gas-phase Al organic species. Alkyl migration from Ga to Al centres takes place, and the presence of Al substantially enhances the irreversible deposition of C. Alkyl migration to In centres is also observed to result in surface etching of In species.