CHRISTOPHER KELLEY JONES
Geologists in Milford, NH
License number
Pennsylvania PG005212
Category
Engineers
Type
Professional Geologist
Address
Address
2
Milford, NH 03055
Pennsylvania
Pennsylvania
Professional information
Method Of Purifying Alkaline-Earth And Alkali-Earth Halides For Crystal Growth
US Patent:
7364620, Apr 29, 2008
Filed:
Oct 28, 2004
Appl. No.:
10/977523
Inventors:
Christopher Daniel Jones - Milford NH, US
Assignee:
Saint-Gobain Ceramics & Plastics, Inc. - Worcester MA
International Classification:
C30B 13/02
US Classification:
117 81, 117 82, 117 83, 117940
Abstract:
An improved technique that reduces the potential for trapped impurities and/or ensuring desired stoichiometry of a grown crystal. Improved contaminant removal is obtained by bubbling a scavenger gas, such as fluorine gas or hydrogen fluoride gas, through a melt of alkaline- or alkali-earth halides, to improve the purity of the melt by removing more volatile metal halides and oxygen contained within the melt. By reacting after the raw material has melted, any oxygen or metal impurities trapped in the raw material is free to react with the scavenger. A desired stoichiometry is achieved as the alkaline- or alkali-earth metals react with the halide in the scavenger gas. Decreasing the amount of impurities in the melt, and using a desired stoichiometeric melt, improves the radiation hardness and transmission properties of resulting ingot grown from the purified raw material. Additionally, this method may decrease the amount of time needed for outgassing. The method may also be used to form a high purity pre-melt, which in turn may be used to grow an ingot with higher purity.