Abstract: 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.

Abstract: The upper electrode 31 has a hole 35 extending from an upper surface 33 to a lower surface 34, a bolt 36 is inserted from the upper surface 33 of the upper electrode 31 into the hole 35, and secured in a lower electrode 32 by a screw. A gap 51 between an inside of the hole 35 and a straight body portion of the bolt 36 allows the upper electrode 31 to slide in all directions in a placement surface (upper surface of the lower electrode 32 in contact with the lower surface 34 of the upper electrode 31 in FIG. 2) that is a contact surface with an upper surface of the lower electrode 32, thereby providing an effect of preventing occurrence of a crack or a break in a U rod that can be expanded and contracted in all directions during a vapor phase growth process.

Abstract: A bell jar includes a metallic bell jar (1), and a metallic base plate (2) on which the bell jar (1) is placed, and packing (3) seals an inside of a container. To the base plate (2), a pressure gauge (4), a gas introduction line (5), and a gas discharge line (6) are connected so as to allow monitoring of internal pressure of the bell jar (1) and introduction and discharge of a gas. A vacuum pump (7) is provided in a path of the gas discharge line (6), and the vacuum pump (7) reduces internal pressure of the bell jar so as to be lower than vapor pressure of water. The vacuum pump (7) reduces the internal pressure of the bell jar so as to be lower than vapor pressure of water, thereby efficiently removing moisture, and completing drying of the bell jar in a short time.

Abstract: 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).

Abstract: A bell jar includes a metallic bell jar (1), and a metallic base plate (2) on which the bell jar (1) is placed, and packing (3) seals an inside of a container. To the base plate (2), a pressure gauge (4), a gas introduction line (5), and a gas discharge line (6) are connected so as to allow monitoring of internal pressure of the bell jar (1) and introduction and discharge of a gas. A vacuum pump (7) is provided in a path of the gas discharge line (6), and the vacuum pump (7) reduces internal pressure of the bell jar so as to be lower than vapor pressure of water. The vacuum pump (7) reduces the internal pressure of the bell jar so as to be lower than vapor pressure of water, thereby efficiently removing moisture, and completing drying of the bell jar in a short time.

Abstract: The upper electrode 31 has a hole 35 extending from an upper surface 33 to a lower surface 34, a bolt 36 is inserted from the upper surface 33 of the upper electrode 31 into the hole 35, and secured in a lower electrode 32 by a screw. A gap 51 between an inside of the hole 35 and a straight body portion of the bolt 36 allows the upper electrode 31 to slide in all directions in a placement surface (upper surface of the lower electrode 32 in contact with the lower surface 34 of the upper electrode 31 in FIG. 2) that is a contact surface with an upper surface of the lower electrode 32, thereby providing an effect of preventing occurrence of a crack or a break in a U rod that can be expanded and contracted in all directions during a vapor phase growth process.

Abstract: 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.

Abstract: 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.

Abstract: One end side of a core wire holder 20 is formed into a shape of a truncated cone and has an inclined surface. In the end portion, an opening 22 is provided, and a hollow portion 21 is formed, a silicon core wire 5 being inserted into the hollow portion 21 and held therein. On the surface of the silicon core wire 5, polycrystalline silicon 6 is vapor deposited by the Siemens method to produce a polycrystalline silicon rod. On the inclined surface of the truncated cone portion in the vicinity of the opening 22, as a thermal insulating layer, annular slits 23a to 23c are formed from an outer circumferential surface in the vicinity of the opening toward the hollow portion 21. The annular slit acts as a thermal insulating portion, and suppresses escape of the heat to heat the one end side of the core wire holder 20.

Abstract: A bell jar includes a metallic bell jar (1), and a metallic base plate (2) on which the bell jar (1) is placed, and packing (3) seals an inside of a container. To the base plate (2), a pressure gauge (4), a gas introduction line (5), and a gas discharge line (6) are connected so as to allow monitoring of internal pressure of the bell jar (1) and introduction and discharge of a gas. A vacuum pump (7) is provided in a path of the gas discharge line (6), and the vacuum pump (7) reduces internal pressure of the bell jar so as to be lower than vapor pressure of water. The vacuum pump (7) reduces the internal pressure of the bell jar so as to be lower than vapor pressure of water, thereby efficiently removing moisture, and completing drying of the bell jar in a short time.

Abstract: The present invention is a method of manufacturing polycrystalline silicon rods, wherein silicon is deposited onto a silicon core wire by a chemical vapor deposition (CVD) method such that a silicon member, which is cut out from a single-crystalline silicon ingot at an off-angle range of 5 to 40 degrees relative to a crystal habit line of the ingot, is used as the silicon core wire. The single-crystalline silicon ingot is preferably grown by a Czochralski (CZ) method or floating zone (FZ) method, such that the ingot preferably has an interstitial oxygen concentration of 7 ppma to 20 ppma. Silicon rods produced by this method are less likely to suffer a breakage caused by cleavage during the growth process of polycrystalline silicon during CVD, and exhibit improved FZ method success rates. The polycrystalline silicon rods produced by this method also have low impurity contamination and high single-crystallization efficiency.

Abstract: 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.

Abstract: 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).

Abstract: The upper electrode 31 has a hole 35 extending from an upper surface 33 to a lower surface 34, a bolt 36 is inserted from the upper surface 33 of the upper electrode 31 into the hole 35, and secured in a lower electrode 32 by a screw. A gap 51 between an inside of the hole 35 and a straight body portion of the bolt 36 allows the upper electrode 31 to slide in all directions in a placement surface (upper surface of the lower electrode 32 in contact with the lower surface 34 of the upper electrode 31 in FIG. 2) that is a contact surface with an upper surface of the lower electrode 32, thereby providing an effect of preventing occurrence of a crack or a break in a U rod that can be expanded and contracted in all directions during a vapor phase growth process.

Abstract: 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.

Abstract: One end side of a core wire holder 20 is formed into a shape of a truncated cone and has an inclined surface. In the end portion, an opening 22 is provided, and a hollow portion 21 is formed, a silicon core wire 5 being inserted into the hollow portion 21 and held therein. On the surface of the silicon core wire 5, polycrystalline silicon 6 is vapor deposited by the Siemens method to produce a polycrystalline silicon rod. On the inclined surface of the truncated cone portion in the vicinity of the opening 22, as a thermal insulating layer, annular slits 23a to 23c are formed from an outer circumferential surface in the vicinity of the opening toward the hollow portion 21. The annular slit acts as a thermal insulating portion, and suppresses escape of the heat to heat the one end side of the core wire holder 20.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The present invention utilizes a silicon member (single-crystalline silicon rod), which is cut out from a single-crystalline silicon ingot which is grown by a CZ method or FZ method, as the core wire when manufacturing a silicon rod. Specifically, a planar silicon is cut out from a body portion which is obtained by cutting off a shoulder portion and a tail portion from a single-crystalline silicon ingot and is further cut into thin rectangles to obtain a silicon bar. In the case that the crystal growth axis orientation is <100>, there are four crystal habit lines, and the silicon bar is cut out such that the surface forms an off-angle ? in a predetermined range with the crystal habit line. The provided polycrystalline silicon rod has a low impurity contamination and high single-crystallization efficiency.