Shin-etsu Chemical Co., Ltd.

Kabushiki Kaisha Toshiba

Mitsubishi Chemical Corporation

Takaaki Shimizu

Tsutomu Ogihara

Tatsushi Kaneko

Takeshi Kinsho

Mutsuo Nakashima

Hideshi Kurihara

Ryuichi Saito

Kyoji Oguro

Kazuyuki Asakura

Masatoshi Takita

Shigeyoshi Netsu

Yasushi Kurosawa

Fumitaka Kume

Toshihiro Okon

Takanobu Takeda

Satoshi Kuwata

Yoshinori Inokuchi

Koji Hasegawa

Toshio Shiobara

Tohru Kubota

Masaki Tanaka

Toshio Ohba

Koji Futatsumori

Masaharu Kaneko

Eiichi Asano

Norio Nakamura

Kazuhiro Arai

Katsuhiro Uehara

Taishi Kobayashi

Masami Kadowaki

Toshiaki Takahashi

Nobuyasu Goto

Takahiro Goi

Kenji Koizumi

Takeshi Aoyama

Takashi Ohkawara

Hironori Iwasaki

Syuji Tanaka

Yutaka Ichinohe

Naoki Nagai

The present invention provides a technique by which heat can be efficiently recovered from a coolant used to cool a reactor, and contamination with dopant impurities from an inner wall of a reactor when polycrystalline silicon is deposited within the reactor can be reduced to produce high-purity polycrystalline silicon. With the use of hot waterhaving a temperature higher than a standard boiling point as a coolant fed to the reactor, the temperature of the reactor inner wall is kept at a temperature of not more than 370&#xb0; C. Additionally, the pressure of the hot waterto be recovered is reduced by a pressure control section provided in a coolant tankto generate steam. Thereby, a part of the hot water is taken out as steam to the outside, and reused as a heating source for another application.

System for producing polycrystalline silicon, apparatus for producing polycrystalline silicon, and process for producing polycrystalline silicon

The present invention provides a method for obtaining high purity chlorosilanes from chlorosilanes containing boron impurities and phosphorus impurities. On the basis of the finding that solid by-product formation in the purification of chlorosilanes by adding an aromatic aldehyde results from a catalytic reaction by iron ions or rust-like iron, a Lewis base having a masking effect is added to chlorosilanes. Examples of the Lewis base include a divalent sulfur-containing compound and an alkoxysilane. The divalent sulfur-containing compound is preferably a compound represented by the formula: R&#x2014;S&#x2014;R' (wherein R is a hydrocarbon group or a carbonyl group; and the sum of the carbon atoms in R and R&#x2032; is 7 or more), and the alkoxysilane is preferably a compound represented by the formula: RSi(OR&#x2032;)(wherein R and R&#x2032; are each an alkyl group having 1 to 20 carbon atoms).

Method for purifying chlorosilanes

An inner wallof a reactorhas a two-layer structure: an anticorrosive layercomprising an alloy material having high anticorrosiveness is provided on the inner side of the reactor contacting a corrosive process gas, and a heat conductive layerfor efficiently conducting the heat within the reactorfrom an inner wall surface to a coolant flow passageis provided on the outer side of the reactor (outer-wall side). The anticorrosive layercomprises an alloy material having a composition for which a value R, defined by R=[Cr]+[Ni]&#x2212;1.5 [Si], is not less than 40% wherein [Cr] is a mass content (% by mass) of chromium (Cr), [Ni] is a mass content (% by mass) of nickel (Ni), and [Si] is a mass content (% by mass) of silicon (Si).

Reactor for producing polycrystalline silicon, system for producing polycrystalline silicon, and process for producing polycrystalline silicon

The present invention provides a technique by which heat can be efficiently recovered from a coolant used to cool a reactor, and contamination with dopant impurities from an inner wall of a reactor when polycrystalline silicon is deposited within the reactor can be reduced to produce high-purity polycrystalline silicon. With the use of hot waterhaving a temperature higher than a standard boiling point as a coolant fed to the reactorthe temperature of the reactor inner wall is kept at a temperature of not more than 370&#xb0; C. Additionally, the pressure of the hot waterto be recovered is reduced by a pressure control section provided in a coolant tankto generate steam. Thereby, a part of the hot water is taken out as steam to the outside, and reused as a heating source for another application.

Methods for producing trichlorosilane, including: reacting a tetrachlorosilane containing substance with hydrogen at a temperature of 400&#xb0; C. to 1,200&#xb0; C. to obtain a mixture including silane, monochlorosilane, dichlorosilane, and trichlorosilane; removing impurities which are electrically active in a semiconductor crystal from the mixture; separating the trichlorosilane from the silane, monochlorosilane and dichlorosilane to obtain purified trichlorosilane; and circulating the silane, monochlorosilane and dichlorosilane obtained from the separating step into the reacting step.

Method for producing trichlorosilane and method for producing polycrystalline silicon

The present invention includes a step of separating an effluent produced in a hydrogenation step of making tetrachlorosilane (STC) react with hydrogen into trichlorosilane (TCS), into a chlorosilane fraction containing a hydrocarbon and a TCS fraction, and a chlorination step of making the chlorosilane fraction containing the hydrocarbon react with chlorine to form STC and a substance containing a chlorinated hydrocarbon, wherein the effluent containing STC produced in the chlorination step is circulated to the hydrogenation step. In the chlorination step, the chlorosilane fraction containing a hydrocarbon (capable of containing hyper-hydrogenated chlorosilanes) having a boiling point close to TCS is hyper-chlorinated to be converted and acquire a higher boiling point, which facilitates the hyper-chlorinated chlorosilanes and the hyper-chlorinated hydrocarbons to be separated into high concentration, and increases the purity of TCS to be finally obtained.

A by-product mixture produced when polycrystalline silicon is deposited on a base material in a CVD reactor is made to react with chlorine to form a tetrachlorosilane (STC) effluent in a chlorination reaction vessel, and the tetrachlorosilane (STC) distillate is made to react with hydrogen in a hydrogenation reaction vessel to be converted into trichlorosilane (TCS). In the chlorination step, poly-silane contained in the above described by-product mixture can be efficiently recycled as a raw material for producing the polycrystalline silicon, which can enhance a yield of the production process. In addition, in the chlorination step, methyl chlorosilanes having boiling points close to TCS are hyper-chlorinated to be converted into hyper-chlorinated methyl chlorosilanes having higher boiling points, which facilitates the hyper-chlorinated methyl chlorosilanes to be separated into high concentration, and reduces carbon contamination of the polycrystalline silicon.

Method for producing polycrystalline silicon

A by-product mixture produced in a process for producing polycrystalline silicon is made to react with chlorine to form tetrachlorosilane (STC) distillate in a chlorination reaction vessel, and the tetrachlorosilane (STC) distillate is made to react with hydrogen in a hydrogenation reaction vessel to be converted into trichlorosilane (TCS). In the chlorination step, methyl chlorosilanes having boiling points close to TCS are hyper-chlorinated to be converted into hyper-chlorinated methyl chlorosilanes having higher boiling points, which facilitates the hyper-chlorinated methyl chlorosilanes to be separated into high concentration, and inhibits carbon from contaminating the polycrystalline silicon. A donor/acceptor eliminator is provided in the circulation cycle for producing TCS, and accordingly there is no need to take out a by-product produced in the process for producing TCS to the outside of the system, which can highly purify the TCS.

Method for producing trichlorosilane

A barcode scanner comprising a laser driving circuit to drive a laser by a pulse signal generated by an oscillator, a preamplifier to amplify a voltage of a barcode signal from a photodetector corresponding to a reflected light from a barcode scanned by a light output of the laser driven by the pulse signal, a high-pass filter to remove a direct current component contained in an output signal of the preamplifier, a variable gain amplifier which controls an amplification gain of an output signal of the high-pass filter and performs automatic gain control to set an output level almost constant, a synchronous detector to detect a pulse signal contained in an output signal of the variable gain amplifier in synchronization with the output pulse of the oscillator, and a binarization circuit to binarize an output signal of the synchronous detector.

Barcode scanner

Amorphous spherical silica microparticulates having a specific surface area of 5-50 m,/g and a particle size distribution of 5-1,000 nm are added to toner particles to form an electrostatic image developer which has improved fluidity and cleaning characteristics. On account of the minimized impurity content of the spherical silica microparticulates, the developer is effective for high-quality and high-speed duplication.

Electrostatic image developer

A silacyclohexane compound of the formulas (I) ##STR1## wherein R represents an organic residue, ##STR2## represents an unsubstituted or substituted silicon-containing cyclohexylene group or a 1,4-cyclohexylene group, ##STR3## represents an unsubstituted or substituted phenylene, an unsubstituted or substituted silicon-containing cyclohexylene group or trans-4-sila-1,4-cyclohexylene group, or a 1,4-cyclohexylene group provided that at least one of these residues represents a silicon-containing cyclohexylene group, j, k and l are, respectively, 0 or 1, L.sub.1 and L.sub.2, respectively, represent H or F, m and n are, respectively, 0, 1 or 2 provided that m+n=2, 3 or 4, and X represents H, F or Cl. A liquid crystal composition comprising the silacyclohexane compound of the above formula is also described, along with a liquid crystal device comprising the composition.

Silacyclohexane compounds, preparation thereof, liquid crystal

The invention presents an excellent liquid crystal display composition possessing a negative dielectric anisotropy, comprising one or more compounds selected from the group consisting of formulas I, II, III, IV and V, ##STR1## where R.sup.1 is alkyl, alkoxyalkyl, mono- or difluoroalkyl, or alkenyl, with each group having 2 to 7 carbon atoms; h, i, j, and k denote 0 or 1 with proviso that i+j=1; m is 0, 1 or 2; a six-membered ring expressed by A, B, or C respectively represents any one of trans-1-sila-1,4-cyclohexylene, trans-4-sila-1,4-cyclohexylene, or trans-1,4-cyclohexylene group; L represents F; and L.sup.1 and L.sup.2 represent H or F; n is 0, 1 or 2; and R.sup.2 is H, R.sup.1 or OR.sup.1, in which at least one compound thereof contains trans-1-sila-1,4-cyclohexylene group or trans-4-sila-1,4-cyclohexylene group.

Liquid crystal composition and liquid crystal display element comprising

A liquid crystal composition having a liquid crystal component with a chemical structure of two saturated rings connected directly to one another, and an additional structural isomer thereof having a silane atom in a different position from the first component and having the structure set forth in formula (1) hereinbelow. ##STR1## This composition provides an improved effect with respect to enhancement in both response speed and T.sub.NI (nematic-isotropic transition temperature) as a high voltage hold ratio as required for TFT driving in addition to also lowering the voltage.

Liquid crystal compositions comprising silacyclohexane compounds

A silacyclohexane compound represented by the following general formula (I). ##STR1## In this formula, R denotes a linear-chain alkyl group with 1-10 carbon atoms, a branched-chain alkyl group with 3-8 carbon atoms, a mono- or di-fluoroalkyl group with 1-10 carbon atoms, an alkoxyalkyl group with 2-7 carbon atoms, or an alkenyl group with 2-8 carbon atoms. ##STR2## is trans-1-silacyclohexylene or trans-4-silacyclohexylene group whose silicon at position 1 or position 4 has a substitutional group(s) of H, F, Cl or CH.sub.3. X denotes a R, OR, CN, F, Cl, CF.sub.3, CF.sub.2 Cl, CHFCl, OCF.sub.3, OCHF.sub.2, OCF.sub.2 Cl, OCHFCl, --(O).sub.m --CY.sub.1 .dbd.CX.sub.1 X.sub.2 (m denotes 0 or 1, Y.sub.1 and X.sub.1 respectively denote H, F or Cl, and X.sub.2 denotes F or Cl) or --O--C.sub.r F.sub.s H.sub.2r+1-s is (r denotes an integral of 2 to 4 and s denotes an integral of 1 to 7) group. Y denotes H or F. Z denotes H or F.

Silacyclohexane compound, a method of preparing it and a liquid crystal

Liquid crystal compositions which can improve the low .DELTA.n (refractive index anisotropy) of conventional liquid crystal compositions containing a silacyclohexane compound and which retain a low viscosity and hence show no decrease in response speed. Liquid crystal compositions having a high .DELTA.n of 0.13 to 0.25, a low viscosity of 30 cp or less, a low threshold voltage and a high voltage holding ratio can be obtained by adding thereto, as a required component, a compound having both a silacyclohexane ring and a tolan structure, or a miture of a compound having a silacyclohexane ring and a compound having a tolan structure.

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Niigata, Japan

Takaaki Shimizu