13 July 1994 Growth of large-area high-quality CdZnTe substrates by the computer-controlled vertical Bridgman method
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Abstract
The reproducible growth of large, high-quality CdZnTe crystals is crucial for providing low- cost substrates for IR focal plane arrays. We have grown 3-kg, 6.4-cm diameter Cd1-xZnxTe (x 0.04) ingots by the vertical Bridgman method, from which we have obtained large-area wafers that can yield single-crystal, twin-free substrates up to 4 cm X 6 cm. The computer-controlled thermal environment was designed to reduce thermal stresses both on the solidified boule and at the melt/solid interface. The ampoule was constructed to reduce the excess Te concentration without active atmosphere control. FTIR transmission spectra of these wafers exhibited 65% transmission from 2.5 micrometers to 20 micrometers across the entire wafer. Glow discharge mass spectrometry (GDMS) confirmed that the concentrations of detrimental impurities were 3 X 1014 cm-3. X-ray synchrotron topography showed that the substrates contained large-area subgrains with minimal residual strain at the boundaries. We discuss the suitability of these substrates for LPE growth of Hg1-yCdxyTe (y 0.2) epilayers.
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Louis G. Casagrande, David J. Larson, Don Di Marzio, Jun Wu, Michael Dudley, David R. Black, Harold Burdette, "Growth of large-area high-quality CdZnTe substrates by the computer-controlled vertical Bridgman method", Proc. SPIE 2228, Producibility of II-VI Materials and Devices, (13 July 1994); doi: 10.1117/12.179680; https://doi.org/10.1117/12.179680
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KEYWORDS
Semiconducting wafers

Tellurium

Cadmium

Crystals

FT-IR spectroscopy

Human-machine interfaces

Mass spectrometry

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