PRECURSOR MEDIATED ADSORPTION OF ORGANOMETALLIC MOLECULES ON GAAS

We have studied the adsorption dynamics of three organometallic compounds of Ga: trimethylgallium, triethylgallium, and diethylgallium chloride on the GaAs(100) As-rich c(2 X 8) surfaces. These three compounds are frequently used for the chemical vapor deposition of GaAs. By monitoring the residence times and sticking coefficients using time-resolved molecular beam/surface scattering, the adsorption of these molecules was shown to be precursor mediated. The accommodation of the kinetic energies of the molecules on the surfaces resulted in the trapping of the molecules. Most of the trapped molecules were chemisorbed at room temperature and trapping-desorption was insignificant until the surface coverage was close to saturation.