CHEMICAL-REACTIONS OF TRIETHYLANTIMONY ON GAAS(100)

The surface chemistry of triethylantimony was studied on GaAs(100) usi ng thermal desorption spectroscopy, static secondary ion mass spectros copy, and x-ray photoelectron spectroscopy. Triethylantimony is revers ibly adsorbed following exposures at 160 K. The saturation coverage at 160 K is approximately 0.3 monolayers, Following triethylantimony exp osure at 330 K, ethylene, the major hydrocarbon reaction product, deso rbs from the GaAs(100) surface during thermal desorption spectroscopy experiments with a peak temperature of 569 K. This indicates a beta-hy dride elimination reaction is responsible for the elimination of ethyl groups from the surface, Additionally, a small amount of ethyl radica ls desorb from the surface. Our results indicate that ethyl groups mig rate to Ga sites and then undergo a beta-hydride elimination reaction at these sites. For saturation coverage (0.3 monolayers), 90% of the t riethylantimony is irreversibly adsorbed. Exposures at 675 K led to ad sorbed Sb atoms as well as GaSb formation, The reactive sticking coeff icient of triethylantimony is low, 4x10(-4), and decreases as the surf ace becomes Sb rich. Eventually adsorption of triethylantimony ceases at 675 K, indicating self-limiting adsorption. (C) 1995 American Vacuu m Society.