DECOMPOSITION KINETICS OF III-V MATERIALS USED FOR MOCVD EPITAXIAL-GROWTH

The decomposition reaction mechanism was experimentally investigated for TMG and arsine used for MOCVD GaAs epitaxial growth. The obtained TMG conversion in H2 showed a decrease-minimum-increase change, as the amount of coexisting arsine was increased. This indicates that the decomposition proceeds according to the following reactions: (1) CH3 elimination, (2) arsine decomposition on the GaAs surface, (3) TMG-H2 reaction (hydrogenolysis), (4) hydrogen radical formation from CH3-H2 reaction, (5) TMG-hydrogen radical reaction, (6) arsine-hydrogen radical reaction, and (7) TMG-arsine reaction on the GaAs surface. The experimental results are explained by assuming the relative magnitudes of the above reaction rates. It is suggested that the arsine-hydrogen radical reaction (6) takes place at a much higher rate than TMG-hydrogen radical reaction (5) and the TMG-arsine surface reaction (7) takes place much more slowly than the CH3 elimination reaction (1). © 1990.