Producible Alternative to CdTe for Epitaxy (PACE-2) of LWIR (Long Wave Infrared) HgCdTe

Abstract

Abstract : This is the final report of the first phase of a program whose objective is the development of a long wave infrared (LWIR) HgCdTe material technology based on heteroepitaxial growth on low cost substrates and to advance this technology to device processing and ultimately focal plane array demonstration. A matrix of five growth techniques and three base substrates (GaAs, Ge and Si) were used to identify the most promising approach. Three epitaxial vapor growth techniques, Laser Assisted Deposition and Annealing (LADA), Molecular Beam Epitaxy (MBE) and Organo-Metallic Vapor Phase Epitaxy (OMVPE) were used to grow epitaxial layers of CdTe on the base substrates. Single crystalline layers of CdTe with near-bulk qualities were obtained on all three base substrates (GaAs, Ge, Si) by all three CdTe vapor growth techniques (LADA, MBE, OM-VPE). OM-VPE growth CdTe on GaAs had the highest crystallinity as determined by x-ray double crystal diffraction. The growth of an additional CdTe layer by Liquid Phase Epitaxy (LPE) improved by the crystallinity of the vapor growth CdTe, but often resulted in higher impurity levels of base substrate elements in the epitaxial CdTe layer due to slight chemical attack of the base substrate during the CdTe LPE cycle. LPE and Isothermal VPE (ISO-VPE) were used for the epitaxial growth of the active HgCdTe layer. Originator furnished keywords include: HgCdTe, Mercury Cadmium Telluride, CdTe, Cadmium Telluride, ISO-VPE, LPE, LADA, MBE, OMVPE, GaAs, Ge, si, PACE-2 Alternative Substrates.