Union Carbide Corporation

David W Hagan

William C Breneman

Robert N Flagella

McRea B Willmert

Thomas R Thoman

Jon M Gaston

William D Burke

The present invention is directed to an improved process for producing ultra high purity polycrystalline silicon which process provides for increased production capacity and electrical power efficiency. The process comprises recycling the exhaust gases of the silane pyrolysis reactor after the gases have been preferably first cooled and filtered utilizing a pocket-type reaction zone enclosure having a particular effective radius thereby effectively decreasing the amount of silicon powder formation. Preferably, the rate of recycle flow is sufficient to entrain silicon powder in the reactor and remove the powder from the reactor with the exiting exhaust gases.

Process for the production of ultra high purity polycrystalline silicon

This invention relates to the manufacture of high-purity polycrystalline silicon rods by the pyrolysis of silane. More specifically, the present invention relates to an improved method for pyrolyzing monosilane to form high-quality polycrystalline rods of uniform diameter and to an improved pyrolysis reactor system for forming high-quality polycrystalline silicon rods of uniform diameter at high production rates.

Reactor system and method for forming uniformly large-diameter

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Vancouver, WA, United States of America

David W Hagan