CHEMICAL COMPATIBILITY STUDIES OF GAAS AND CDZNTE WITH THE ALLOYS WC-103 AND TZM

The objective of this study was to determine the chemical compatibilit y of gallium arsenide (GaAs) and cadmium zinc telluride (CdZnTe) with WC-103, a niobium hafnium titanium alloy, and TZM, a titanium zirconiu m molybdenum alloy. Compatibility in these systems is of primary inter est for crystal growth experiments during space shuttle missions. Crys tal growth ampoules containing GaAs and CdZnTe must be encased in a sa mple 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 couple s between the semiconductors and the metals were constructed and used to simulate failure of the growth ampoule. Experiments were designed t o 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 m icroscope to evaluate any metal loss or reaction products formed.