Mass-spectrometric study of the pyrolysis reactions in the MOVPE of Ga2Se3 by in-situ gas sampling

Abstract An investigation of the thermal decomposition reactions of trimethylgallium (Me 3 Ga) and hydrogen selenide (H 2 Se) using hydrogen as a carrier gas involved in the growth of Ga 2 Se 3 (and/or GaSe) was undertaken, using a simple mass spectrometric sampling system on a conventional atmospheric pressure metalorganic vapour phase epitaxy reactor, MOVPE, reactor. The mass fragments corresponding to the unreacted precursor species as well as stable volatile hydrocarbon products were monitored using a quadrupole mass spectrometer as the temperature of the susceptor, the VI III ratio and the precursor mole fractions were varied. The only gas phase hydrocarbon product detected was methane. Possible mechanisms for the reaction of Me 3 Ga with hydrogen selenide have been investigated theoretically and the implications of these results for the growth of Ga 2 Se 3 (and/or GaSe) epilayers are discussed.