Transportation in MOCVD of traces of oxygenated aluminum and gallium organometallics

Gas-phase transportation of dimethylmethoxy compounds of aluminum and galli um, which contaminate corresponding trimethyl metal compounds used in MOCVD , were investigated. It was found that larger amounts of oxygenated compoun ds were transported than can be calculated from the vapor pressure ratio of Me2MOMe (I) to Me3M (II). A decrease in the ratio (m/n) of the concentrati on of oxygenated compound (m) in the bubbler to the concentration of that t ransported to the reactor (n) was observed, especially at very low content of I in Me3M. The H-1-NMR and cryometric studies strongly suggest that an e quilibrium between the system of trimeric dimethylmetal methoxy compound (M e3M)(n) and mixed species [GRAPHICS] exists in the mixture: [GRAPHICS] The presence of III, more volatile than (Me2MOMe)(3), rationalizes the high er transportation ratio. (C) 2000 Elsevier Science S.A. All rights reserved .