Effects of methylarsine homologs (CH3)nAsH3−n on the metalorganic vapor-phase epitaxy of GaAs

Abstract

We have investigated the methyl derivatives of arsine, (CH₃)_nAsH_3−n (n=1–3), in metalorganic vapor‐phase epitaxy of GaAs to determine the effects of the degree of hydrogen atom substitution on film properties. Direct comparisons were obtained in the same reactor under identical conditions of the thermal decomposition and growth characteristics of the methylarsine reactants and arsine. The relative thermal stability of the As precursors, AsH₃>Me_nAsH_3−n>Et₃As>t‐BuAsH₂, did not correlate with differences observed in their film growth rates. The quality of GaAs films grown with the methylarsines was limited by both the incorporation of carbon from the precursor reactant itself, and by extrinsic donor and acceptor contaminants present in the source material. Film electrical properties appeared to be dominated at low temperatures (<650 °C) by the thermochemistry of the methylarsine species, and at higher temperatures by the doping characteristics of the extrinsic impurities.