REDUCTION
Once it has been analyzed, the trichlorosilane liquid is vaporized, mixed with hydrogen gas and sent to a reduction or Chemical Vapor Deposition (CVD) furnace. During the chemical vapor deposition process, silicon from the gas stream is deposited on thesurface of electrically heated polysilicon seed rods. The reduction furnace is precisely controlled to grow the polysilicon rod to a predetermined diameter. Exhaust gases which are released during this process are cooled, liquefied and distilled, yielding theco-products silicon tetrachloride (STC)

HYDROGEN RECYCLE
Hydrogen recycle is an important support unit to reduction and distillation. The plant receives the exhaust gas from the reduction plant. The gas consists of hydrogen and recovered chlorosilanes from the reduction reaction. The plant condenses the chlorosilanes and sends them to the distillation plant for recovery of the pure TCS and STC materials. The hydrogen goes through a clean up process and is then recycled back to the reduction plant in a continuous recovery loop.