摘要:
An inner wall 11 of a reactor 10 has a two-layer structure: an anticorrosive layer 11a comprising an alloy material having high anticorrosiveness is provided on the inner side of the reactor contacting a corrosive process gas, and a heat conductive layer 11b for efficiently conducting the heat within the reactor 10 from an inner wall surface to a coolant flow passage 13 is provided on the outer side of the reactor (outer-wall side). The anticorrosive layer 11a comprises an alloy material having a composition for which a value R, defined by R=[Cr]+[Ni]−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).
摘要:
A hydrogenation reaction vessel makes STC-containing substance react with hydrogen to convert the substance into TCS. A low boils removal column separates a chlorosilane distillate discharged from a hydrogenation reaction vessel into TCS and a mixture distillate containing hyper-hydrogenated chlorosilane, and circulates the mixture distillate containing hyper-hydrogenated chlorosilane to the hydrogenation reaction vessel. The mixture distillate containing the hyper-hydrogenated chlorosilane separated in the low boils removal column is circulatingly supplied to the hydrogenation reaction vessel. Accordingly, low boils by-product conventionally wasted is circulated and recycled in the process, which results in enhancing a yield of TCS production.
摘要:
Methods for producing trichlorosilane, including: reacting a tetrachlorosilane containing substance with hydrogen at a temperature of 400° C. to 1,200° 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.
摘要:
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 water 15 having a temperature higher than a standard boiling point as a coolant fed to the reactor 10, the temperature of the reactor inner wall is kept at a temperature of not more than 370° C. Additionally, the pressure of the hot water 15 to be recovered is reduced by a pressure control section provided in a coolant tank 20 to 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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
An inner wall 11 of a reactor 10 has a two-layer structure: an anticorrosive layer 11a comprising an alloy material having high anticorrosiveness is provided on the inner side of the reactor contacting a corrosive process gas, and a heat conductive layer 11b for efficiently conducting the heat within the reactor 10 from an inner wall surface to a coolant flow passage 13 is provided on the outer side of the reactor (outer-wall side). The anticorrosive layer 11a comprises an alloy material having a composition for which a value R, defined by R=[Cr]+[Ni]−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).
摘要:
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 water 15 having a temperature higher than a standard boiling point as a coolant fed to the reactor 10, the temperature of the reactor inner wall is kept at a temperature of not more than 370° C. Additionally, the pressure of the hot water 15 to be recovered is reduced by a pressure control section provided in a coolant tank 20 to 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.
摘要:
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.