Accession Number : ADA297062

Title :   An Accelerated Program for Low-cost CdZnTe/GaAs/Si Substrates for MCT Infrared Focal Plane Arrays.

Descriptive Note : Final rept. 5 Jun 92-31 Jul 93,

Corporate Author : SPIRE CORP BEDFORD MA

Personal Author(s) : Karam, Nasser H.

PDF Url : ADA297062

Report Date : 21 JUL 1994

Pagination or Media Count : 47

Abstract : The objective of this program was to develop CdZnTe/GaAs/Si alternative substrates by metalorganic chemical vapor deposition (MOCVD) for MCT liquid-phase epitaxy (LPE). The purpose was to make available larger, more robust, and far less expensive substrates than currently produced bulk CdZnTe, the substrates should be compatible with LPE and free of the limitation on detector array dimensions imposed by the thermal expansion mismatch between mercury-cadmium-telluride and bump-bonded silicon circuitry. As a result at the substrate I program a thermal oxide encapsulant has been developed that is impervious to the Te-rich LPE melt and is not wetted by it. This encapsulant has made it possible to reduce the Ga impurity level in LPE HgCdTe to below 1 x 10 to the 15th atoms/cu. cm. At the same time it has been found possible to produce CdZnTe deposits with a (111) B orientation that are free of twins at the surface and are of excellent crystalline quality with dislocation densities of down to 500,000/sq cm and an X-ray rocking curve FWHM of below 80 arc sec. Long-wave infrared diodes with a quantum efficiency of 50% (when illuminated through the uncoated Si substrate) have been produced form this material. (MM)

Descriptors :   *EPITAXIAL GROWTH, *INFRARED SPECTRA, DIODES, LOW COSTS, GALLIUM ARSENIDES, THIN FILMS, ARRAYS, ORGANOMETALLIC COMPOUNDS, CHEMICAL VAPOR DEPOSITION, SUBSTRATES, SILICON, CADMIUM TELLURIDES, ENCAPSULATION, WAFERS, FOCAL PLANES.

Subject Categories : Optics
      Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE