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WO2007013644A1 - Procédé servant à produire du silicium polycristallin - Google Patents

Procédé servant à produire du silicium polycristallin Download PDF

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Publication number
WO2007013644A1
WO2007013644A1 PCT/JP2006/315088 JP2006315088W WO2007013644A1 WO 2007013644 A1 WO2007013644 A1 WO 2007013644A1 JP 2006315088 W JP2006315088 W JP 2006315088W WO 2007013644 A1 WO2007013644 A1 WO 2007013644A1
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WO
WIPO (PCT)
Prior art keywords
silicon
metal
chlorosilane
melting point
gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2006/315088
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English (en)
Japanese (ja)
Inventor
Toshiharu Yamabayashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Chemical Co Ltd
Original Assignee
Sumitomo Chemical Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Chemical Co Ltd filed Critical Sumitomo Chemical Co Ltd
Publication of WO2007013644A1 publication Critical patent/WO2007013644A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • C01B33/021—Preparation
    • C01B33/027—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
    • C01B33/033—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material by reduction of silicon halides or halosilanes with a metal or a metallic alloy as the only reducing agents

Definitions

  • the present invention relates to a method for producing polycrystalline silicon. Specifically, the present invention relates to a method for producing polycrystalline silicon with a high yield.
  • An object of the present invention is to provide a method for producing polycrystalline silicon with a high yield.
  • the present inventor has intensively studied a method for producing polycrystalline silicon, and as a result, has completed the present invention.
  • the present invention provides: [1] a metal having a lower free energy of formation of metal chloride than silicon and a metal having a melting point lower than that of silicon;
  • n an integer of 0 to 3.
  • a method for producing polycrystalline silicon is provided.
  • the present invention also provides [2] a method for producing polycrystalline silicon including steps (i) and (ii), (i) a metal chloride free energy of formation lower than that of silicon, and a metal melting point lower than that of silicon.
  • step (i) when the gaseous chlorosilane is blown into the molten metal,
  • the temperature of the genus is 1.03 times or more and less than 1.79 times the melting point of the metal expressed in absolute temperature, the temperature is kept below the melting point of silicon, and the number of moles of chlorosilane supplied per minute is Less than 1.0 percent of the number of moles of
  • metal according to any one of [1] to [4], wherein the metal is at least one selected from the group consisting of potassium, cesium, rubidium, strontium, lithium, sodium, magnesium, aluminum, zinc, and manganese.
  • a solar cell comprising polycrystalline silicon obtained by the method according to any one of [1] to [8] is provided.
  • Figure 1 shows an overview of the reactor.
  • Figure 2 shows the gas supply system
  • Figure 3 represents the yield of S i C 1 4 / A 1 molar ratio and S i.
  • Thermostatic bath 10 Best mode for carrying out the invention
  • a metal chloride generation free energy is lower than that of silicon and a metal melting point is lower than that of silicon, and a gaseous chlorosilane represented by the above formula (1) is reacted. Is the method.
  • a gas containing chlorosilane is blown into a molten metal to react the metal with gaseous chlorosilane.
  • the temperature of the molten metal is 1.0 3 times or more, preferably 1.10 times or more, more preferably 1. 20 times or more, 1. Less than 79 times, preferably less than 1.50 times, more preferably less than 1.40 times, below the melting point of silicon.
  • the number of moles of chlorosilane supplied per minute is less than 1.0 percent, preferably 0.5 percent or less, relative to the number of moles of metal.
  • the number of moles of chlorosilane supplied is usually 0.01 to the number of moles of metal. % Or more, preferably 0.1% or more.
  • the gas blown into the molten metal may be chlorosilane alone or a mixed gas of chlorosilane and inert gas.
  • the gas concentration of chlorosilane in the mixed gas is preferably 10% by volume or more.
  • inert gas examples include nitrogen gas, argon gas, helium gas, and neon gas, and argon gas is preferable from the viewpoint of reducing the reaction with chlorosilane and the availability.
  • Metals have lower free energy and melting point for metal chlorides than silicon.
  • Examples of the metal include potassium, cesium, rubidium, strontium, lithium, sodium, magnesium, aluminum, zinc, and manganese.
  • metal aluminum is preferably used. The higher the purity of the metal, the higher the purity of the silicon produced, so boron (B) and phosphorus (P) are less than l p p m
  • chlorosilanes silicon tetrachloride, trichlorosilane, dichlorosilane, and monochlorosilane can be used, but hydrogen-containing trichlorosilane, dichlorosilane, and monochlorosilane generate hydrogen chloride by reaction. Induces corrosion of piping. For this reason, it is preferable to use tetrachlorosilane alone.
  • the purity of chlorosilane is that B and P are less than l p p m, 99.9
  • a metal chloride produced as a by-product by reacting with a metal for example,
  • silicon can be obtained in an amount of more than 40% of the weight of the metal used, so that the yield of the obtained silicon is high, which is economically advantageous.
  • the material for holding the metal and the gas introduction pipe for introducing chlorosilane usually does not react with the metal used, and examples thereof include oxides, nitrides, and carbides.
  • the oxide include silica, alumina, zirconia, titania, zinc oxide, magnesia, and tin oxide.
  • the nitride include silicon nitride and aluminum nitride. These constituent elements may be partially substituted with other elements, for example, compounds such as sialon composed of silicon, aluminum, oxygen and nitrogen may be used.
  • Examples of the carbide include SiC, graphite, and the like, and these constituent elements may be partially substituted with other elements.
  • At least one gas inlet tube is installed on the top or side of the molten metal and blown from there, or the molten metal does not leak due to surface tension at the bottom of the container holding the molten metal It is only necessary to install many holes of the same size and blow from there. Even when a large number of holes for introducing gas are provided, the number of moles of chlorosilane supplied per minute is within the above range.
  • the obtained polycrystalline silicon has a high purity and is suitably used as a raw material for solar cell silicon.
  • the obtained polycrystalline silicon can be treated with acid or alkali to remove the unreacted metal component residue, segregation such as directional solidification, dissolution at high vacuum, etc. May be applied.
  • acid or alkali to remove the unreacted metal component residue, segregation such as directional solidification, dissolution at high vacuum, etc. May be applied.
  • the metal and silicon used for the reduction are in a molten state, or the metal and silicon.
  • the temperature of the system can be reduced by lowering the temperature of the system below the reaction temperature or cooling a specific part of the reactor. Silicon deposits corresponding to the lowered amount are obtained. If a metal having the same weight as the deposited silicon is added and the temperature is raised to the reaction temperature, and then chlorosilane is added, the silicon concentration rises to a predetermined concentration. If this operation is repeated, silicon can be obtained continuously.
  • the obtained silicon is usually formed by a casting method or an electromagnetic forging method to obtain an ingot.
  • the conductivity type of the substrate is generally p-type, and can be achieved, for example, by adding boron or leaving aluminum as a dopant.
  • Ingots are usually sliced by cutting the inner peripheral edge, etc., then both sides are lapped with loose abrasive grains, and further immersed in an etching solution such as hydrofluoric acid to remove the damaged layer. Is obtained.
  • a V-groove is mechanically formed using a dicing machine, or a texture structure is formed by reactive ion etching or isotropic etching using acid. It is formed.
  • a diffusion layer of an n-type dopant such as phosphorus or arsenic is formed on the light receiving surface to obtain a pn junction.
  • the electrodes on each side of the oxide film layer, such as a T I_ ⁇ 2 after forming on the surface it forms the shape of the anti-reflection film such as M g F 2 for reducing the loss of light energy due to reflection, solar A battery cell is produced.
  • Figure 1 shows an outline of the reactor.
  • Alumina Tanman tube 4 (Nitsukato SSA—S, T 5 (inner diameter ⁇ 30)) containing aluminum 5 is held in alumina container 3 and held in vertical annular furnace 1, 1273K (melting point of aluminum tetrachloride Kei-containing gas (mixture gas of S i C 1 4 / Ar) 6 was reacted by introducing into the molten aluminum 1. 36x) of.
  • the aluminum used has a purity of 99.999 wt% [impurity concentration Fe 0.73 ppm, Si 2. 7 ppm, Cu 1.9 ppm, Mg O. 45 ppm, B 0.05 ppm, P 0.27 p pm (according to the results of glow discharge mass spectrometry (GDMS analysis))), and its weight was 25 g (0.93 mol).
  • the purity of aluminum is obtained by subtracting the total weight% of impurities Fe, Si, Cu, and Mg from 100%.
  • the tetrachlorosilane is manufactured by Trichemical Laboratories with a purity of 99.9999% by weight (6) [impurity concentration: Fe 5.2 ppb, A 1 0.8 ppb, Cu 0.9 9 pp b, Mg 0. 8 p pb, Na 2.4 ppb, Ca 5.5 ppb (P and B are less than l ppm)].
  • the distance between the tip of the gas inlet tube 2 [Nichikato SSA-S, (outer diameter ⁇ 6, inner diameter ⁇ 4)] and the bottom of the Tamman tube was 5 mm.
  • Figure 2 shows the gas supply system
  • the transport of the tetrachlorobenzene is Argon gas (made by Japan AG) (purity 99 ⁇ 9 995%) was supplied as 0. IMP a and used as a carrier gas.
  • Argon gas made by Japan AG
  • the stainless steel container containing the tetrachloride cage 9 was held in a constant temperature bath 10 at 20 ° C. Since the vapor pressure of silicon tetrachloride at the same temperature is 193 mmHg, the concentration of the gas is 25.4% by volume.
  • the concentration of carbon tetrachloride gas charged into the reactor is 13.9% by volume.
  • the amount of supply of tetrachlorosilane per minute is 0.431 g, which is 0.0025 mol. Therefore, the number of moles of chlorosilane supplied is 0.27% with respect to the number of moles of aluminum.
  • the gas was allowed to flow for 16 hours and 30 minutes, and then cooled to recover a 14 g sample.
  • the sample was dissolved in hydrochloric acid and the silicon weight in the sample was determined, it was found to be 82% by weight.
  • the weight of silicon obtained for the input aluminum is
  • Impurity elements contained in silicon can be further reduced by unidirectionally solidifying the obtained silicon.
  • Example 2 An alumina protective tube containing aluminum (SSA-S, No.9 (inner diameter ⁇ 16) manufactured by Nikato) is held in an alumina container and held in a vertical annular furnace, 1273K (the melting point of aluminum) 1.36 times the same), and tetrachloromethane gas was introduced into the molten aluminum for 5 hours to react. The same aluminum and tetrachlorosilane as in Example 1 were used. The weight of aluminum was 12 g (0.44 mol).
  • the distance between the tip of the gas inlet pipe [Nichikato SSA-S, (outer diameter ⁇ 6, inner diameter 4)] and the bottom of the alumina protective tube was 5 mm.
  • the transfer of silicon tetrachloride was carried out as a carrier gas by supplying argon gas (manufactured by Japan AG) (purity 99.9 995%) at 0. IMP a.
  • 104SCCM flow rate 104 mLZmin, 0 ° C, 101.3 kPa
  • argon gas is allowed to flow as the carrier gas, and the gas obtained by evaporation is directly used as the carrier. It was introduced into the reactor along with the gas.
  • the supply of silicon tetrachloride per minute is 0.595 g, which is 3.5X 10-3 moles. Therefore, the moles of silicon tetrachloride supplied is 0.8% of the moles of aluminum.
  • the stainless steel container containing silicon tetrachloride is held in a thermostatic chamber of 318 K, and the vapor pressure of silicon tetrachloride at the same temperature is 50 OmmHg (66.6 kPa). The concentration of the gas is 66% by volume.
  • Impurity elements contained in silicon can be further reduced by unidirectionally solidifying the obtained silicon.
  • the temperature is cooled to, for example, 1073 K, and silicon is deposited and taken out at a specific site. If the same weight of aluminum as recon is added and kept at 1273 K, further addition of silicon tetrachloride will increase the silicon concentration to 61%. By repeating this operation, silicon can be obtained continuously. The obtained silicon is considered suitable as a raw material for solar cells.
  • the weight of aluminum is 6.0 g (0.22 mol), and argon is 334 SCCM (flow rate 334 mL / min, 0 ° C, 101.3 kPa) as the carrier gas in the tetrachlorosilane gas container.
  • the gas obtained by flowing and evaporating the gas was introduced into the reactor together with the carrier gas.
  • the supply amount of silicon tetrachloride per minute is 1.912 g, which is 0.011 mol. Therefore, the number of moles of silicon tetrachloride supplied is 5% of the number of moles of aluminum.
  • Hydrogen tetrachloride gas was introduced into the molten aluminum for 2 hours to react. Other than that, the examination was performed in the same manner as in Example 2.
  • the weight of aluminum is 6.0 g (0.22 mol), and argon is 174 S CCM (flow rate 174 mL Zm i n., 0 ° C, 101.3 kPa) as the carrier gas in the tetrachlorosilane gas container.
  • the gas obtained by flowing and evaporating the gas was introduced into the reactor together with the carrier gas as it was.
  • Supply amount tetrachloride Kei containing per minute is 0. 996 g, a 5. 9 ⁇ 10- 3 moles. (The number of moles of silicon tetrachloride supplied is 2.7% of the number of moles of aluminum.) Carbon tetrachloride gas was introduced into molten aluminum for 2 hours to react. Other than that, the examination was performed in the same manner as in Example 2.
  • polycrystalline silicon can be produced with high yield.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Silicon Compounds (AREA)

Abstract

Procédé servant à produire du silicium polycristallin lequel comprend de faire réagir un métal, dont le chlorure a une énergie libre de formation inférieure à celle du silicium et dont le point de fusion est inférieur à celui du silicium, avec un chlorosilane gazeux représenté par la formule (1) suivante : SiHnCl4-n (1) (dans laquelle n est un nombre entier de 0-3). Dans le procédé, on fait buller le chlorosilane gazeux dans une masse fondue du métal tout en maintenant le métal fondu à une température qui n'est pas inférieure à 1,03 fois le point de fusion du métal, en termes de température absolue, et qui est inférieure à 1,79 fois le point de fusion de celui-ci et qui est inférieure au point de fusion du silicium. On introduit le chlorosilane à un débit tel que le nombre de moles du chlorosilane introduit par minute est inférieur à 1,0 pour cent des moles du métal.
PCT/JP2006/315088 2005-07-28 2006-07-25 Procédé servant à produire du silicium polycristallin Ceased WO2007013644A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2005218495 2005-07-28
JP2005-218495 2005-07-28

Publications (1)

Publication Number Publication Date
WO2007013644A1 true WO2007013644A1 (fr) 2007-02-01

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008034576A1 (fr) * 2006-09-22 2008-03-27 Umicore PRODUCTION DE Si PAR RÉDUCTION DE SiCl4 AU MOYEN DE Zn LIQUIDE, ET PROCÉDÉ DE PURIFICATION
WO2008034578A1 (fr) * 2006-09-22 2008-03-27 Umicore Procédé de production d'alliages de silicium comportant du germanium
WO2008034577A1 (fr) * 2006-09-22 2008-03-27 Umicore PROCÉDÉ DE PRODUCTION DE Si PAR RÉDUCTION DE SiHCl3 AU MOYEN DE Zn LIQUIDE
WO2008145236A1 (fr) * 2007-05-25 2008-12-04 Umicore Procédé économique de production de si par réduction de sicl4 avec du zn liquide

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59182221A (ja) * 1983-03-24 1984-10-17 バイエル・アクチエンゲゼルシヤフト ケイ素の製法
JPH0264006A (ja) * 1988-07-15 1990-03-05 Bayer Ag 太陽のシリコンの製造方法
JPH11199216A (ja) * 1998-01-12 1999-07-27 Kawasaki Steel Corp シリコンの一方向凝固装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59182221A (ja) * 1983-03-24 1984-10-17 バイエル・アクチエンゲゼルシヤフト ケイ素の製法
JPH0264006A (ja) * 1988-07-15 1990-03-05 Bayer Ag 太陽のシリコンの製造方法
JPH11199216A (ja) * 1998-01-12 1999-07-27 Kawasaki Steel Corp シリコンの一方向凝固装置

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008034576A1 (fr) * 2006-09-22 2008-03-27 Umicore PRODUCTION DE Si PAR RÉDUCTION DE SiCl4 AU MOYEN DE Zn LIQUIDE, ET PROCÉDÉ DE PURIFICATION
WO2008034578A1 (fr) * 2006-09-22 2008-03-27 Umicore Procédé de production d'alliages de silicium comportant du germanium
WO2008034577A1 (fr) * 2006-09-22 2008-03-27 Umicore PROCÉDÉ DE PRODUCTION DE Si PAR RÉDUCTION DE SiHCl3 AU MOYEN DE Zn LIQUIDE
WO2008145236A1 (fr) * 2007-05-25 2008-12-04 Umicore Procédé économique de production de si par réduction de sicl4 avec du zn liquide

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