GROWTH AND CHARACTERIZATION OF GALLIUM-ARSENIDE USING SINGLE-SOURCE PRECURSORS - OMCVD AND BULK PYROLYSIS STUDIES

Films of gallium arsenide have been grown on GaAs(100), GaAs(111), and α-Al2O3(0001) at 1 × 10−4 Torr and 525 °C by using a single-source precursor [Me2Ga(μ-t-Bu2As)]2 (1) and H2 carrier gas. These conditions resulted in GaAs growth rates of 0.75 μm/h. The carbon content of the films was less than the XPS detection limit (1000 ppm). Secondary ion mass spectrometry (SIMS) revealed that carbon was not incorporated from the precursor. Photoluminescence spectra (5 K) of the material grown on α-Al2O3(0001) exhibited the 1.52-eV bandgap of GaAs. However, the material appears degeneratively doped. X-ray diffraction, Berg-Barrett topography, and pole figure analysis indicated that these GaAs films are (111) orientated and polycrystalline. Mass spectroscopic analysis of the OMCVD reaction of 1 revealed that the volatile products are predominantly isobutylene and methane. Bulk pyrolysis studies demonstrated that at lower temperatures (350 °C) the decomposition of 1 is incomplete and that isobutane is produced in addition to isobutylene and methane. Under similar conditions, the decomposition of [n-Bu2Ga(μ-t-Bu2As)]2 (2) is virtually complete. The thermolysis of 2 produced isobutane (60%), isobutylene (32%), n-butane (9.6%), 1-butene (44%), trans-2-butene (26%), and cis-2-butene (19%). © 1990, American Chemical Society. All rights reserved.