Chemical compatibility studies of GaAs and CdZnTe with the alloys WC-103 and TZM

Abstract

The objective of this study was to determine the chemical compatibility of gallium arsenide (GaAs) and cadmium zinc telluride (CdZnTe) with WC-103, a niobium hafnium titanium alloy, and TZM, a titanium zirconium molybdenum alloy. Compatibility in these systems is of primary interest for crystal growth experiments during space shuttle missions. Crystal growth ampoules containing GaAs and CdZnTe must be encased in a sample ampoule cartridge assembly (SACA) during crystal growth, which is qualified as a level of safety containment. Two of the primary metal candidates for these containment cartridges for experiments conducted aboard the USML-1 shuttle mission were WC-103 and TZM. Reaction couples between the semiconductors and the metals were constructed and used to simulate failure of the growth ampoule. Experiments were designed to examine various stages of failure including the worst case situation, in which failure occurred at the beginning of the growth experiment. The couples were analyzed optically and using the scanning electron microscope to evaluate any metal loss or reaction products formed.