The adsorption and reaction of triethylgallium on GaAs(100)

Abstract

The surface chemistry of triethylgallium (TEGa) on both Ga-rich and As-rich GaAs(100) was studied using Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and temperature programmed desorption (TPD). TEGa desorbs molecularly from two states with peak temperatures of about 323 and 523 K after TEGa exposure at 123 K on the Ga-rich surface. These conclusions of molecular desorption are in contrast to previous work which has been interpreted in terms of both TEGa and diethylgallium (DEGa) desorption above 150 K. The major products of TEGa decomposition, in agreement with previous work, are ethylene, hydrogen, and a small amount of ethyl radical. The saturation coverage of ethylene molecules and hydrogen atoms was measured to be ∼ 1 × 10 14 cm −2. The total ethyl radical yield is estimated to be 8% of the saturation ethylene coverage (∼ 9 × 10 12 molecules cm −2). On the As-rich surface, more TEGa desorption is observed in comparison to the Ga-rich conditions. The decomposition products are identical to those observed for the Ga-rich surface; however, the relative amounts of ethyl radicals to ethylene and hydrogen are significantly different.