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Title: Electromigration process for the purification of molten silicon during crystal growth

Abstract

A process for the purification of molten materials during crystal growth by electromigration of impurities to localized dirty zones. The process has particular applications for silicon crystal growth according to Czochralski techniques and edge-defined film-fed growth (EFG) conditions. In the Czochralski crystal growing process, the impurities are electromigrated away from the crystallization interface by applying a direct electrical current to the molten silicon for electromigrating the charged impurities away from the crystal growth interface. In the EFG crystal growth process, a direct electrical current is applied between the two faces which are used in forming the molten silicon into a ribbon. The impurities are thereby migrated to one side only of the crystal ribbon. The impurities may be removed or left in place. If left in place, they will not adversely affect the ribbon when used in solar collectors. The migration of the impurity to one side only of the silicon ribbon is especially suitable for use with asymmetric dies which preferentially crystallize uncharged impurities along one side or face of the ribbon.

Inventors:
 [1];  [1]
  1. (San Pedro, CA)
Issue Date:
Research Org.:
California Institute of Technology
OSTI Identifier:
864209
Patent Number(s):
4330359
Assignee:
Lovelace, Alan M. Administrator of National Aeronautics and Space (San Pedro, CA);Shlichta, Paul J. (San Pedro, CA) OSTI
DOE Contract Number:  
NAS7-100
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
electromigration; process; purification; molten; silicon; crystal; growth; materials; impurities; localized; dirty; zones; particular; applications; according; czochralski; techniques; edge-defined; film-fed; efg; conditions; growing; electromigrated; crystallization; interface; applying; direct; electrical; current; electromigrating; charged; applied; forming; ribbon; migrated; removed; left; adversely; affect; solar; collectors; migration; impurity; especially; suitable; asymmetric; dies; preferentially; crystallize; uncharged; molten materials; silicon crystal; growth process; direct electrical; solar collectors; solar collector; particular application; electrical current; crystal growth; especially suitable; molten material; adversely affect; particular applications; silicon ribbon; molten silicon; crystal growing; growth interface; growing process; asymmetric die; efg crystal; /117/136/

Citation Formats

Lovelace, Alan M. Administrator of the National Aeronautics and Space, and Shlichta, Paul J. Electromigration process for the purification of molten silicon during crystal growth. United States: N. p., 1982. Web.
Lovelace, Alan M. Administrator of the National Aeronautics and Space, & Shlichta, Paul J. Electromigration process for the purification of molten silicon during crystal growth. United States.
Lovelace, Alan M. Administrator of the National Aeronautics and Space, and Shlichta, Paul J. Fri . "Electromigration process for the purification of molten silicon during crystal growth". United States. https://www.osti.gov/servlets/purl/864209.
@article{osti_864209,
title = {Electromigration process for the purification of molten silicon during crystal growth},
author = {Lovelace, Alan M. Administrator of the National Aeronautics and Space and Shlichta, Paul J.},
abstractNote = {A process for the purification of molten materials during crystal growth by electromigration of impurities to localized dirty zones. The process has particular applications for silicon crystal growth according to Czochralski techniques and edge-defined film-fed growth (EFG) conditions. In the Czochralski crystal growing process, the impurities are electromigrated away from the crystallization interface by applying a direct electrical current to the molten silicon for electromigrating the charged impurities away from the crystal growth interface. In the EFG crystal growth process, a direct electrical current is applied between the two faces which are used in forming the molten silicon into a ribbon. The impurities are thereby migrated to one side only of the crystal ribbon. The impurities may be removed or left in place. If left in place, they will not adversely affect the ribbon when used in solar collectors. The migration of the impurity to one side only of the silicon ribbon is especially suitable for use with asymmetric dies which preferentially crystallize uncharged impurities along one side or face of the ribbon.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1982},
month = {1}
}

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