Editing Silicon tetrachloride (section)

==Uses==
Silicon tetrachloride is used as an intermediate in the manufacture of [[polysilicon]], a hyper-pure form of silicon,<ref name=Ullmann/> since it has a boiling point convenient for purification by repeated [[fractional distillation]]. It is reduced to [[trichlorosilane]] (HSiCl<sub>3</sub>) by hydrogen gas in a hydrogenation reactor, and either directly used in the [[Siemens process]] or further reduced to [[silane]] (SiH<sub>4</sub>) and injected into a [[fluidized bed reactor]]. Silicon tetrachloride reappears in both these two processes as a by-product and is recycled in the hydrogenation reactor. [[Epitaxy#Vapor-phase|Vapor phase epitaxy]] of reducing silicon tetrachloride with hydrogen at approximately 1250&nbsp;°C was done:
: {{chem|SiCl|4}}(g) + 2 {{chem|H|2}}(g) → Si(s) + 4 {{chem|H|Cl|}}(g) at 1250°C<ref name="Morgan&Board">{{cite book|last1=Morgan|first1=D. V.|last2=Board|first2=K.|title=An Introduction To Semiconductor Microtechnology|date=1991|publisher=John Wiley & Sons|location=Chichester, West Sussex, England|isbn=0471924784|page=23|edition=2nd}}</ref>

The produced polysilicon is used as wafers in large amounts by the [[Photovoltaics|photovoltaic]] industry for conventional solar cells made of [[crystalline silicon]] and also by the semiconductor industry.

Silicon tetrachloride can also be hydrolysed to [[fumed silica]]. High purity silicon tetrachloride is used in the manufacture of optical fibres. This grade should be free of hydrogen containing impurities like trichlorosilane. Optical fibres are made using processes like MCVD and OFD where silicon tetrachloride is oxidized to pure silica in the presence of oxygen.

As a feedstock in production of [[Fused quartz|fused silica]].