Motorola Corporation

Robert D Darnell

William M Ingle

Carl A Goetz

Stephen W Thompson

Reaction vessels, furnace tubes, heating and cooling enclosures frequently have parts such as access ports, inlet tubes, inspection windows, etc. made of thermally transparent materials such as plastic, glass, quartz, oxides, nitrides and sulfides. When these parts extend outside the hot zone, they can act as 'light pipes' carrying appreciable amounts of thermal radiation which can damage thermally sensitive gaskets or other materials used to secure external couplings or end closure flanges to these parts. Thermal radiation induced gasket damage is a frequent cause of stuck flanges and couplings. This problem is avoided by inserting a thermal radiation scattering region in the thermally transparent material between the hot zone and the end closure or gaskets. The thermal radiation is scattered and dispersed, so that the end zones receive less radiation and remain cooler. Milky quartz is a suitable scattering material for use with quartz furnace tubes or bell jars.

Method of cooling a flange and coupling

An improved means and method for extracting polycrystalline silicon from silicon source gases is provided wherein seed particles and source gases are reacted in a rising particle reaction chamber in which the gas velocity is sufficient to entrain and eject all seed particles smaller than a predetermined size while those which have grown to a larger size fall through the rising gas stream and are extracted from the base of the reactor. Those seed particles which are ejected from the reaction column are separated from the spent gases and fall back into a concentric reservoir. A first gas not containing any silicon is supplied to a nozzle within the reservoir and creates a first gas-particle mixture which is injected into an auxiliary mixing chamber, where it is further mixed with a high velocity lifting gas which includes the source gases. The lifting and source gas-particle mixture is swept through the reactor where silicon deposits on the seed particles. The seed particles recirculate from reaction column to reservoir to reaction column until they have achieved sufficient size so as to be automatically harvested by the differential lifting action in the reaction column.

Ascending differential silicon harvesting means and method

Flange and coupling cooling means and method

A process is disclosed for the purification of trichlorosilane and other silicon source materials. Trace impurities of boron and phosphorous are removed from trichlorosilane or dichlorosilane by reacting small amounts of oxygen with the trichlorosilane or dichlorosilane at a temperature between about 60.degree. C. and 300.degree. C. The oxygen reacts with the Si--H bond in HSiCl.sub.3 or H.sub.2 SiCl.sub.2 to form a 'SiOH' species which in turn complexes impurities such as BCl.sub.3 or PCl.sub.3 present in the chlorosilane. Purification of the chlorosilane is then easily accomplished during a subsequent distillation step which separates the purified chlorosilane from the less volatile complexed boron or phosphorous compounds.

Purification of silicon source materials

A process is disclosed for the purification of trichlorosilane and other silicon source materials. Trace impurities of boron and phosphorous are removed from trichlorosilane by reacting small amounts of oxygen with the trichlorosilane at a temperature between about 170.degree. and 300.degree. C. The oxygen reacts with the Si--H bond in HSiCl.sub.3 to form a 'SiOH' species which in turn complexes impurities such as BCl.sub.3 or PCl.sub.3 present in the trichlorosilane. Purification of the trichlorosilane is then easily accomplished during a subsequent distillation step which separates the purified trichlorosilane from the less volatile complexed boron or phosphorous compounds.

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Phoenix, AZ, United States of America

Robert D Darnell