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Silicon Refining Through Chemical Vapor Deposition

Currently the cost of solar grade silicon accounts for approximately one third of the total solar cell cost, therefore a new silicon refining process is being proposed with the goal of lowering the cost of producing solar grade silicon.
In this new process, Si-Cu alloys were used as the silicon source. One to one molar ratio H2-HCl gas mixtures were used as transport agents to extract Si out from the Si-Cu alloy at about 300-700oC, with following reaction taking place:

Si+3HCl(g)=HSiCl3(g)+H2(g)

While at about 1000-1300oC, pure Si deposits onto a hot silicon rod according to:

Si+3HCl(g)=HSiCl3(g)+H2(g)

The role of the copper in the alloy was to trap impurities in the Si and catalyze the gas solid reaction. A study on determining the rate limiting step and impurity behavior was done. A possible silicon extraction reaction mechanism was also addressed.

Identiferoai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/25713
Date03 January 2011
CreatorsLI, Mark Xiang
ContributorsUtigard, Torstein A.
Source SetsUniversity of Toronto
Languageen_ca
Detected LanguageEnglish
TypeThesis

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