Growth of Mercury Cadmium Telluride by Current Controlled Liquid Phase Epitaxy.
Final rept. 30 Sep 78-29 Sep 79,
BROOKLYN COLL N Y
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We have grown crystalline epitaxial layers of mercury cadmium telluride from a mercury-rich melt by the method of constant temperature current controlled liquid phase epitaxy CCLPE. CCLPE is an attractive method of crystal growth for mercury cadmium telluride because it has the potential for achieving better uniformity than bulk crystal techniques. In addition it can be used for direct growth of p-n junctions by addition of suitable dopants. The lower growth temperature compared to bulk growth methods is expected to result in fewer vancancies. Growth was achieved under conditions where the substrate was hotter than the source as well as circumstances where the substrate was colder than the source. This indicated that the mass transport was driven by electromigration rather than the Peltier effect. Several layers were grown to a thickness of 30-100 microns. Best results were obtained on 111 oriented substrates. These layers were studied micrographically and with the use of X-ray diffraction methods. One 500 micron thick layer was also investigated by the electrolyte electroreflectance method in order to determine composition and homogeneity. This piece was found to have a mole fraction of cadmium telluride equal to 0.1. This represented a considerable mercury enrichment over the substrate and source. The variation in mole fraction of cadmium telluride over the surface of the sample approx. 1 sq cm was approximately 0.03.
- Solid State Physics