WO2019095634A1 - Procédé de synthèse de matière première de carbure de silicium de haute pureté et application correspondante - Google Patents

Procédé de synthèse de matière première de carbure de silicium de haute pureté et application correspondante Download PDF

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Publication number
WO2019095634A1
WO2019095634A1 PCT/CN2018/084427 CN2018084427W WO2019095634A1 WO 2019095634 A1 WO2019095634 A1 WO 2019095634A1 CN 2018084427 W CN2018084427 W CN 2018084427W WO 2019095634 A1 WO2019095634 A1 WO 2019095634A1
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silicon carbide
raw material
silicon
reaction
furnace
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PCT/CN2018/084427
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English (en)
Chinese (zh)
Inventor
高超
窦文涛
张红岩
李长进
李加林
宗艳民
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山东天岳先进材料科技有限公司
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Publication of WO2019095634A1 publication Critical patent/WO2019095634A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B35/00—Apparatus not otherwise provided for, specially adapted for the growth, production or after-treatment of single crystals or of a homogeneous polycrystalline material with defined structure
    • C30B35/007—Apparatus for preparing, pre-treating the source material to be used for crystal growth
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/36—Carbides

Definitions

  • the invention belongs to the technical field of crystal growth, and in particular relates to a method for synthesizing high-purity silicon carbide raw materials and an application thereof.
  • silicon carbide single crystals have unmatched physical properties such as large band gap, high saturation electron mobility, strong breakdown field and high thermal conductivity.
  • silicon carbide devices in the fields of power electronics, radio frequency devices, optoelectronic devices, etc. continue to deepen and expand, and the corresponding quality requirements for silicon carbide materials are also constantly increasing.
  • the physical vapor transport (PVT) method is currently the main technology used in the industrial production of silicon carbide materials.
  • the PVT method uses silicon carbide particles as a raw material, and a gas phase source produced by sublimation of a silicon carbide raw material is transported to a seed crystal at a high temperature to be recrystallized.
  • the SiC raw material is synthesized by the reaction of silicon powder and carbon powder at a high temperature. During the synthesis process, residual air in the synthesis chamber and impurities adsorbed by the raw material and equipment may contaminate the final product, resulting in a higher concentration of impurities in the SiC raw material. Especially nitrogen impurities.
  • Avinash K Gupta et al proposed adding solid silicon oxide (such as solid SiO or SiO 2 ) in the growth chamber in order to supplement the silicon component during crystal growth. Thereby reducing the formation of carbon-rich components and thereby inhibiting the formation of carbon inclusions [US 2008/0115719 A1].
  • the present invention proposes a synthesis method and application of a high-purity silicon carbide raw material, and solves the problem of impurities and inclusion defects in the growth process of the SiC single crystal from the source of the growth of the SiC single crystal.
  • the method for synthesizing a high-purity silicon carbide raw material according to the present invention has the following specific steps:
  • the pressure in the reactor is reduced to 500-800 mbar, and the temperature of the reaction furnace is raised to 1800-2300 ° C at a heating rate of 100-200 ° C / h for 20-30 h to obtain silicon carbide-coated silicon.
  • High-purity silicon carbide particles which are high-purity silicon carbide raw materials.
  • the carbon powder particles react with the silicon powder particles to form SiC crystal grains; in order to accelerate the reaction rate between the silicon powder particles and the carbon powder particles, the temperature is lowered during the temperature drop.
  • reaction process described in the present invention is three steps, and the specific reaction process is illustrated as follows:
  • the silicon powder reacts with oxygen to form a silica coating layer, which prevents the silicon powder from adsorbing nitrogen; then, the silicon powder coated with the oxide layer is in the reaction of the carbon powder, and the carbon first coats with the silicon dioxide layer.
  • the present invention finally obtains high purity particles in which the outer layer structure is silicon carbide and the inner layer is coated with silicon.
  • the present invention forms a high-purity granule of SiC-coated Si having an outer layer of SiC and an inner layer of Si by a three-step reaction technique.
  • the reaction chamber of the present invention is a coating layer, and the plating layer is tantalum carbide.
  • the plating material is used to protect the graphite crucible, prevent the Si atmosphere generated during crystal growth from eroding the graphite crucible, and avoid the release of free carbon particles from the graphite crucible.
  • the particle size of the silicon powder and carbon powder will affect the reaction rate and the degree of reaction, which in turn affects the quality of the synthetic SiC powder.
  • the silicon powder according to the present invention has a particle size of 1-5 mm, and the carbon powder has a particle size of 10-50 mm. If the particle size of the silicon powder is too large or the particle size of the toner is too small, the residual Si element in the synthesized SiC powder will be excessive. On the contrary, the particle structure of the carbon powder reacted with the surface of the silicon particles to form the SiC-coated Si will not be formed. .
  • the gas flow ratio of the inert shielding gas and oxygen is 10,000 to 20,000:1.
  • the reaction furnace is evacuated to remove residual air and harmful impurities in the furnace chamber to obtain a clean environment conducive to the synthesis of high-purity SiC powder.
  • the introduction of a large amount of inert gas (such as high purity argon, purity 5N or 6N) is to protect the chamber environment of SiC powder synthesis, while controlling the oxygen flow at a lower level to fully react with the silicon powder particles. can. Excessive oxygen or too little inert gas can cause danger (excessive oxygen at high temperatures and residual gases).
  • the flow rate of oxygen is usually controlled at 1-3 SCCM, and the general introduction time of inert gas and oxygen is 5-10 h, so that an oxide film is formed on the surface of the silicon powder particles.
  • the temperature and pressure are set so that the Si particles sufficiently react with the C powder and the oxygen and the Si particles sufficiently react. If the temperature is too low or the time is too short, the reaction may be incomplete. If the temperature is too high or the time is too long, the SiC particles which are completely reacted may be sublimated and carbonized, and the efficiency is lowered and the cost is increased.
  • the vacuum of the reaction furnace in steps (2) and (6) is 10 -6 mbar.
  • the boosting time in steps (3) and (7) is 1-2 h.
  • the molar ratio of the silicon particles to the carbon powder is 1:1, in order to ensure that the silicon powder particles completely react the carbon powder particles, and the SiC grains after the reaction are kept coated with the silicon powder particles.
  • Excessive toner can cause incomplete reaction of the toner particles, and residual carbon particles in the formed SiC raw material will affect the subsequent crystal quality; a similar excess of silicon powder will result in incomplete reaction of the silicon powder particles.
  • the invention has the following advantages:
  • Si is coated in the interior of SiC.
  • the Si coated inside can continue to react with the residual carbon to form a new SiC.
  • the reduction of carbon particles can reduce the formation of carbon inclusions in the SiC single crystal during the growth process.
  • a method for synthesizing a high-purity silicon carbide raw material the specific steps of which are:
  • the pressure in the reactor is reduced to 500 mbar, and the temperature of the reactor is raised to 1800 ° C at a heating rate of 100 ° C / h for 20 h to obtain high-purity silicon carbide particles coated with silicon carbide. High purity silicon carbide raw materials.
  • the reaction chamber is a coating layer, and the plating layer is tantalum carbide.
  • the silicon powder has a particle size of 1-2 mm, and the carbon powder has a particle size of 10-20 mm.
  • the inert gas and oxygen flow rate is 10,000:1; the oxygen flow rate is controlled at 1 SCCM, and the general inert gas and oxygen are introduced for 5 h.
  • the vacuum of the reaction furnace in steps (2) and (6) is 10 -6 mbar.
  • the boosting time in steps (3) and (7) is 1 h.
  • the high-purity silicon carbide raw material prepared by the above has a boron element concentration of less than 0.01 ppm, an aluminum element concentration of less than 0.05 ppm, a vanadium element concentration of less than 0.01 ppm, an iron element concentration of less than 0.05 ppm, and a nickel element concentration of less than 0.01 ppm.
  • the chromium element concentration is less than 0.5 ppm. According to the conventional PVT method, SiC single crystal growth can be carried out to obtain a high-quality high-purity SiC single crystal without carbon inclusion defects.
  • a method for synthesizing a high-purity silicon carbide raw material the specific steps of which are:
  • the pressure in the reactor is reduced to 600 mbar, and the temperature of the reaction furnace is raised to 1900 ° C at a heating rate of 200 ° C / h for 30 h to obtain high-purity silicon carbide particles of silicon carbide-coated silicon. High purity silicon carbide raw materials.
  • the reaction chamber is a coating layer, and the plating layer is tantalum carbide.
  • the silicon powder has a particle size of 2-4 mm, and the carbon powder has a particle size of 10-30 mm.
  • the gas flow ratio of the inert shielding gas and oxygen is 15000:1.
  • the flow rate of oxygen is controlled at 3SCCM, and the general inert gas and oxygen are introduced for 6 hours.
  • the vacuum of the reaction furnace in steps (2) and (6) is 10 -6 mbar.
  • the boosting time in steps (3) and (7) is 2h.
  • the high-purity silicon carbide raw material prepared by the above has a boron element concentration of less than 0.01 ppm, an aluminum element concentration of less than 0.05 ppm, a vanadium element concentration of less than 0.01 ppm, an iron element concentration of less than 0.05 ppm, and a nickel element concentration of less than 0.01 ppm.
  • the chromium element concentration is less than 0.5 ppm. According to the conventional PVT method, the SiC single crystal is grown to obtain a high-quality high-purity SiC single crystal without carbon inclusion defects.
  • a method for synthesizing a high-purity silicon carbide raw material the specific steps of which are:
  • the pressure in the reactor crucible is reduced to 700 mbar, and the temperature of the reactor crucible is raised to 2000 ° C at a heating rate of 150 ° C / h for 25 h to obtain high-purity silicon carbide particles of silicon carbide-coated silicon. High purity silicon carbide raw materials.
  • the reaction chamber is a coating layer, and the plating layer is tantalum carbide.
  • the silicon powder has a particle size of 3-5 mm, and the carbon powder has a particle size of 40-50 mm.
  • the inert gas flow rate of the protective gas and oxygen is 20,000:1.
  • the flow rate of oxygen is controlled at 2 SCCM, and the general inert gas and oxygen are introduced for 7 hours.
  • the vacuum of the reaction furnace in steps (2) and (6) is 10 -6 mbar.
  • the boosting time in steps (3) and (7) was 1.5 h.
  • the high-purity silicon carbide raw material prepared by the above has a boron element concentration of less than 0.01 ppm, an aluminum element concentration of less than 0.05 ppm, a vanadium element concentration of less than 0.01 ppm, an iron element concentration of less than 0.05 ppm, and a nickel element concentration of less than 0.01 ppm.
  • the chromium element concentration is less than 0.5 ppm. According to the conventional PVT method, the SiC single crystal is grown to obtain a high-quality high-purity SiC single crystal without carbon inclusion defects.
  • a method for synthesizing a high-purity silicon carbide raw material the specific steps of which are:
  • the pressure in the reactor crucible is reduced to 800 mbar, and the temperature of the reactor crucible is raised to 2100 ° C at a heating rate of 200 ° C / h for 22 h to obtain high-purity silicon carbide particles coated with silicon carbide, which is High purity silicon carbide raw materials.
  • the reaction chamber is a coating layer, and the plating layer is tantalum carbide.
  • the silicon powder has a particle size of 4-5 mm, and the carbon powder has a particle size of 30-50 mm.
  • the inert gas flow rate of the protective gas and oxygen is 18,000:1.
  • the flow rate of oxygen is controlled at 1 SCCM, and the general inert gas and oxygen are introduced for 8 hours.
  • the vacuum of the reaction furnace in steps (2) and (6) is 10 -6 mbar.
  • the boosting time in steps (3) and (7) was 1.2 h.
  • the high-purity silicon carbide raw material prepared by the above has a boron element concentration of less than 0.01 ppm, an aluminum element concentration of less than 0.05 ppm, a vanadium element concentration of less than 0.01 ppm, an iron element concentration of less than 0.05 ppm, and a nickel element concentration of less than 0.01 ppm.
  • the chromium element concentration is less than 0.5 ppm. According to the conventional PVT method, the SiC single crystal is grown to obtain a high-quality high-purity SiC single crystal without carbon inclusion defects.
  • a method for synthesizing a high-purity silicon carbide raw material the specific steps of which are:
  • the pressure in the reactor is reduced to 650 mbar, and the temperature of the reaction furnace is raised to 2300 ° C at a temperature increase rate of 100 ° C / h for 27 h to obtain high-purity silicon carbide particles of silicon carbide-coated silicon. High purity silicon carbide raw materials.
  • the reaction chamber is a coating layer, and the plating layer is tantalum carbide.
  • the silicon powder has a particle size of 1-3 mm, and the carbon powder has a particle size of 20-40 mm.
  • the gas flow ratio of inert shielding gas and oxygen is 12000:1.
  • the flow rate of oxygen is controlled at 3SCCM, and the general inert gas and oxygen are introduced for 10 hours.
  • the vacuum of the reaction furnace in steps (2) and (6) is 10 -6 mbar.
  • the boosting time in steps (3) and (7) was 1.7 h.
  • the high-purity silicon carbide raw material prepared by the above has a boron element concentration of less than 0.01 ppm, an aluminum element concentration of less than 0.05 ppm, a vanadium element concentration of less than 0.01 ppm, an iron element concentration of less than 0.05 ppm, and a nickel element concentration of less than 0.01 ppm.
  • the chromium element concentration is less than 0.5 ppm. According to the conventional PVT method, the SiC single crystal is grown to obtain a high-quality high-purity SiC single crystal without carbon inclusion defects.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)

Abstract

La présente invention concerne le domaine technique de la croissance des cristaux, et concerne plus particulièrement un procédé de synthèse d'une matière première de carbure de silicium de haute pureté et une application correspondante, le procédé consistant : au moyen d'une technique de réaction en trois étapes, à former une particule de haute pureté dans laquelle du SiC recouvre du Si, une couche extérieure étant du SiC et une couche intérieure étant du Si ; à revêtir le Si à l'intérieur du SiC, et lorsqu'un monocristal de SiC de haute pureté est développé par utilisation de la particule comme matière première, à sublimer une couche de surface de SiC, puis à former du carbone résiduel. Le silicium qui recouvre l'intérieur peut continuer à réagir avec le carbone résiduel pour former du nouveau SiC, ce qui permet de maintenir en continu le rapport Si/C en équilibre ; la réduction simultanée des particules de carbone permet de réduire la formation d'inclusions de carbone dans les monocristaux de SiC pendant la croissance du cristal. Ainsi, les problèmes d'impuretés et le défaut d'inclusion de carbone pendant la croissance des monocristaux de SiC sont résolus à partir de la source de croissance de monocristal de SiC.
PCT/CN2018/084427 2017-11-14 2018-04-25 Procédé de synthèse de matière première de carbure de silicium de haute pureté et application correspondante WO2019095634A1 (fr)

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