Motorola Corporation

Other

William M Ingle

Robert D Darnell

Stephen W Thompson

Carl A Goetz

Robert A Frosch

Christian A Seelbach

Robert E Chaney

H S Setty

Marilyn S Peffley

Carl Goetz

A process and apparatus for LPCVD of thin metallic films is disclosed. The apparatus includes a U-shaped injection tube through which high molecular weight reactants are injected into a reaction chamber. The input and output ends of the U-shaped tube are coupled to a removeable feedthrough plate which, in turn, is coupled to the end cap which seals one end of the reaction chamber. A deposition surface is placed in the chamber through a second end cap at the opposite end of the chamber. The output end of the U-shaped injection tube is coupled to a vacuum pump and the high molecular weight reactant is drawn through the injection tube and dispersed in the reaction chamber through a plurality of holes in the input side of the injection tube.

Process and apparatus for the low pressure chemical vapor deposition of

A process for producing trichlorosilane and equipment for practicing that process are disclosed. The process is a two stage process which combines the reaction of silicon tetrachloride and hydrogen with silicon with the reaction of hydrogen chloride with silicon. In one embodiment of the invention a two stage reactor is provided with a first stage heated to a temperature of about 500.degree.-700.degree. C. and a second stage maintained at a temperature of about 300.degree.-350.degree. C. Each of the first and second stages of the reactor are charged with silicon particles. A mixture comprising hydrogen and silicon tetrachloride are flowed through the silicon particles in the heated first stage to cause a partial hydrogenation of the silicon tetrachloride. The effluent from the first stage includes trichlorosilane and unreacted hydrogen and silicon tetrachloride. Hydrogen chloride is added to this effluent and the mixture of gases are passed through the silicon particles in the second stage of the reactor.

Trichlorosilane production process

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.

A ball valve particularly suited for use in the handling of highly corrosive fluids characterized by a valve housing formed of communicating segments of quartz tubing, a pair of communicating sockets disposed in coaxial alignment with selected segments of tubing for establishing a pair of inlet ports communicating with a common outlet port, a ball formed of quartz material supported for displacement between the sockets and configured to be received alternately thereby, and a valve actuator including a rod attached to the ball for selectively displacing the ball relative to each of the sockets for controlling fluid flow through the inlet ports.

Quartz ball valve

A method wherein a quartz tube is charged with chunks of metallurgical grade silicon and/or a mixture of such chunks and high purity quartz sand, and impurities from a class including aluminum, boron, and the like, as well as certain transition metals including nickel, iron, manganese and the like. The tube is then evacuated and heated to a temperature within a range of 800.degree. C. to 1400.degree. C., whereupon a stream of gas comprising a reactant, such as silicon tetrafluoride, continuously is delivered at low pressures through the charge for causing a metathetical reaction of impurities of the silicon and the reactant to occur for forming a volatile halide and leaving a residue of silicon of an improved purity. Additionally, the reactant may include carbon monoxide gas, whereby impurites such as iron and nickel react therewith to form volatile carbonyls.

Method of purifying metallurgical grade silicon employing reduced

A process for producing semiconductor grade silicon. Metallurgical grade silicon, silicon dioxide, and silicon tetrafluoride are chemically combined at an elevated temperature to form silicon difluoride gas. The silicon difluoride gas is then polymerized, preferably in a two-step process. An initial small quantity of silicon difluoride polymers is formed at a first temperature. This initial polymerization removes most of the impurities that were present in the original metallurgical grade silicon and which were transported by the silicon difluoride gas. The bulk of the remaining silicon difluoride gas is then polymerized at a second, lower temperature. These polymers are substantially free from all impurities. The pure silicon difluoride polymers are then thermally decomposed at temperatures below 400.degree. C. to form binary silicon fluoride homologues. The homologues can be distilled for even higher purity, or can be used or stored as formed. The binary silicon fluoride homologues produce pure silicon and silicon tetrafluoride when heated to a temperature between 400.degree. C. and 950.degree. C. The disproportionation of the homologues can be accomplished by chemical vapor deposition techniques onto heated substrates of silicon, metal, or quartz. This disproportionation will result in amorphous, polycrystalline, or monocrystalline silicon depending on the temperatures employed and on the substrate used for deposition.

Silicon purification process

Truly amorphous silicon having a low level of undesired impurities, and therefore suitable for semiconductor applications, may be prepared by the present process. Impure silicon, for example, metallurgical grade silicon, is prepared at an elevated temperature, e.g., above 1400.degree. C. The impure silicon and at least one binary silicon fluoride compound, e.g., silicon tetrafluoride, are chemically combined at the elevated temperature to form silicon difluoride gas. The silicon difluoride gas is polymerized. The silicon difluoride polymer is then thermally decomposed to produce the purified, amorphous silicon and binary silicon fluoride by-products. The binary silicon fluorides are recycled in the process to be chemically combined with the impure silicon. That step and the succeeding steps serve to reduce the level of unwanted impurities in the silicon produced by at least several orders of magnitude.

Growing community of inventors

Phoenix, AZ, United States of America

William M Ingle