ROLE OF GAS-PHASE ADDUCTS IN THE GROWTH OF GALLIUM-ARSENIDE BY METALORGANIC VAPOR-PHASE EPITAXY

Heating hex-5-enylarsine (hexAsH2) in the presence of trimethylgallium in solution produces methylenecyclopentane via a series of intermediates which include the adduct, [Me3Ga - As(hex)H2]. In the gas phase, the major C6 product obtained from decomposition of hexAsH2 in the presence or absence of Me3Ga is hex-1-ene, indicating that the adduct is not formed to any significant extent in the gas phase. Calculations on [Me3Ga . AsH3] indicate that, whereas at room temperature the formation constant from Me3Ga and AsH3 is 0.24, the unfavorable entropy of this formation reaction ensures that the adduct will not be present to a significant extent in the gas phase at 900 K.