Single-crystal – oriented-crystal – and epitaxy growth processes; – Processes of growth from liquid or supercritical state – Having moving solid-liquid-solid region
Patent
1998-05-15
2000-11-07
Utech, Benjamin
Single-crystal, oriented-crystal, and epitaxy growth processes;
Processes of growth from liquid or supercritical state
Having moving solid-liquid-solid region
117939, C30B 1310
Patent
active
061430706
ABSTRACT:
The present invention describes the growth of single crystals of non-congruently melting alloys, in particular, silicon-germanium of constant composition in a quartz ampoule by the use of CaCl.sub.2 as an encapsulant for the liquid encapsulated zone melting (LEZM) technique. The zone melting process was modified with the addition of calcium chloride which acts as a liquid encapsulant at temperatures above 660.degree. C. so that the crystal can grow without sticking to the container. The calcium chloride encapsulant creates a non-wetting buffer layer between the quartz container and the SiGe charge material allowing single crystal growth of mixed alloys. The crystal growth system consists of a vertical tube RF furnace with a water cooled split-ring concentrator. The concentrator is 5 mm. Thick by 25 mm diameter and provides a high temperature melt zone with a "spike" profile. The single crystal seed and the polycrystalline alloy charge are loaded into a quartz ampoule which fits freely through the concentrator coil. The encapsulant calcium chloride is placed on top of the charge so that when it melts, it covers the inner surface of the quartz ampoule. During operation the alloy charge is melted in the "spike" zone at the seed interface, and then the molten zone is translated along the length so that a single crystal of uniform composition is formed.
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Bailey John
Bliss David F.
Demczyk Brian G.
Chen Kin-Chan
Collier Stanton E.
The United States of America as represented by the Secretary of
Utech Benjamin
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