Stephen Michael Pope

US Patent:

59000600, May 4, 1999

Filed:

Jul 3, 1996

Appl. No.:

8/675141

Inventors:

Jeffrey E. Nause - Atlanta GA
D. Norman Hill - Chamblee GA
Stephen G. Pope - Greer SC

Assignee:

Cermet, Inc. - Atlanta GA

International Classification:

C30B 1102

US Classification:

117223

Abstract:

The invention is directed to an apparatus, system and methods for growing high-purity crystals of substances that are peritectic at atmospheric pressure. The apparatus includes a pressure vessel that contains a pressurized gas. The apparatus also includes a cooling unit that is situated in the pressure vessel. The cooling unit receives a coolant flow from outside of the vessel, and has cooled surfaces that define an enclosure that receives the charge material. The apparatus further includes an inductive heating element situated in the vessel, that is coupled to receive electric power externally to the vessel. The element heats the interior portion of the charge material to form a molten interior portion contained by a relatively cool, exterior solid-phase portion of the charge material that is closer relative to the molten interior, to the cooled surfaces of the cooling unit. Because the exterior portion is the same material as the contained molten interior portion, few impurities are introduced to the molten interior portion of the charge material. Due to the pressure exerted by the gas contained in the vessel, the liquid interior of the charge material becomes congruently melting to prevent its peritectic decomposition.

US Patent:

58633260, Jan 26, 1999

Filed:

Mar 14, 1997

Appl. No.:

8/818393

Inventors:

Jeffrey E. Nause - Atlanta GA
D. Norman Hill - Chamblee GA
Stephen G. Pope - Greer SC

Assignee:

Cermet, Inc. - Atlanta GA

International Classification:

C30B 1520

US Classification:

117217

Abstract:

The invention is directed to an apparatus, system and methods for growing high-purity crystals of substances that are peritectic at atmospheric pressure using the Czochralski technique. The apparatus includes a pressure vessel that contains a pressurized gas. The apparatus also includes a cooling unit that is situated in the pressure vessel. The cooling unit receives a coolant flow from outside of the vessel, and has cooled surfaces that define an enclosure that receives the charge material. The apparatus further includes an inductive heating element situated in the vessel, that is coupled to receive electric power externally to the vessel. The element heats the interior portion of the charge material to form a molten interior portion contained by a relatively cool, exterior solid-phase portion of the charge material that is closer relative to the molten interior, to the cooled surfaces of the cooling unit. Because the exterior portion is the same material as the contained molten interior portion, few impurities are introduced to the molten interior portion of the charge material. Due to the pressure exerted by the gas contained in the vessel, the liquid interior of the charge material becomes congruently melting to prevent its peritectic decomposition.