The Role of Arsine in Reducing Carbon in Triethylarsenic Grown GaAs Films

Abstract

AbstractVery high carbon impurity levels (1018-1021cm−3) in GaAs films grown using triethylarsenic (Et3As) and trimethylgallium (Me3Ga) can be dramatically reduced by substituting a portion of the Et3As reagent with arsine during growth. Gallium arsenide epilayers grown at a deposition temperature of 560°C, a total V/III ratio =10, and the Group V reagent consisting of a mixture of Et3As and arsine, were found to exhibit carbon levels of only 5-7×1015cm−3for Group V mixtures ranging from 0-65% Et3As. All of these films were n-type, except for those grown using 100% arsine, which were p-type. The reduction in carbon incorporation in films grown using Et3As and arsine as co-reagents is shown to result from a unique, synergistic, reaction chemistry involving the two arsenic reagents. In particular, the decomposition of arsine to provide carbon-free, active arsenic fragments for growth is greatly enhanced by the presence of Et3As as a co-reactant.