CVD CDZNTE AS A SUBSTRATE FOR HGCDTE DETECTORS

THE PERFORMANCE OF PHOTOVOLTAIC AND PHOTOCONDUCTIVE HGCDTE INFRARED DETECTOR, FOCAL PLANE ARRAYS IS CURRENTLY LIMITED DUE TO MATERIALS PROBLEMS ASSOCIATED WITH THE CDTE SUBSTRATES. THE MATERIAL CDZNTE, A PSEUDOBINARY SYSTEM, HAS BEEN IDENTIFIED AS A POTENTIALLY SUPERIOR SUBSTRATE MATERIAL DUE TO ITS ABILITY TO PROVIDE A PRECISE LATTICEMATCH TO HGCDTE AND POSSIBLY AN IMPROVED QUALITY, CRYSTALLINE STRUCTURE. THE AIM OF THIS PROGRAM WILL BE TO ESTABLISH GROWTH CONDITIONS WHICH WILL PROVIDE HIGH PURITY, HIGH QUALITY EPITAXIAL CDZNTE MATERIAL, PERFORM DETAILED CHARACTERIZATION OF THE MATERIAL AND DEMONSTRATE THE SUPERIORITY OF LATTICE MATCHED CDZNTE SUBSTRATE MATERIAL FOR HGCDTE DETECTORS. IN PHASE I OF THIS PROGRAM, THE FEASIBILITY OF GROWING HIGH QUALITY EPILAYERS OF CDZNTE ON FIVE DIFFERENT SUBSTRATE MATERIALS - INSB, GAAS, SILICON, CDTE AND SAPPHIRE VIA THE LOW PRESSURE CVD PROCESS WILL BE PERFORMED. THE MATERIAL CDZNTE WILL BE FABRICATED BY USING H2TE GAS AND ELEMENTAL CADMIUM AND ZINC METALS IN A CVD REACTOR. THE EPILAYERS WILL BE CHARACTERIZED BY EXAMINING SURFACE MORPHOLOGY UNDER AN ORDINARY AND SCANNING ELECTRON MICROSCOPES, PERFORMING SCANNING ELECTRON MICROSCOPE ENERGY DISPERSIVE X-RAY ANALYSIS (SEM-EDAX) AND X-RAY DIFFRACTION ANALYSIS.