THE EPITAXIAL-GROWTH OF ALGAAS USING HIGH PURIFIED TRIMETHYLALUMINUM

Highly purified trimethylaluminum [(CH3)3Al] was prepared by reducing the contamination of volatile impurities such as organic silicon and dimethyl-aluminum methoxide [(CH3)2AlOCH3]. The concentration of methoxy group in (CH3)3Al was found to decrease considerably when (CH3)3Al was distilled in the presence of aluminum trihalide. Among the halides, purification efficiency increased in the order I > Br > Cl. High-quality AlGaAs layer and AlGaAs/GaAs modulation doped structures were grown by organometallic vapor-phase epiloxy (OMVPE) using the purified (CH3)3Al. Their electrical properties were discussed in relation to the volatile impurity in the source gas.