WO2023119874A1 - POLYCRYSTALLINE SiC MOLDED BODY - Google Patents

POLYCRYSTALLINE SiC MOLDED BODY Download PDF

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WO2023119874A1
WO2023119874A1 PCT/JP2022/040454 JP2022040454W WO2023119874A1 WO 2023119874 A1 WO2023119874 A1 WO 2023119874A1 JP 2022040454 W JP2022040454 W JP 2022040454W WO 2023119874 A1 WO2023119874 A1 WO 2023119874A1
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sic
plane
polycrystalline sic
polycrystalline
main surface
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PCT/JP2022/040454
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French (fr)
Japanese (ja)
Inventor
卓志 飯田
郁哉 ▲高▼橋
聖 福田
博之 神藤
励子 屋敷田
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東海カーボン株式会社
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Priority to JP2023513087A priority Critical patent/JPWO2023119874A1/ja
Publication of WO2023119874A1 publication Critical patent/WO2023119874A1/en

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
    • C04B41/81—Coating or impregnation
    • C04B41/85—Coating or impregnation with inorganic materials
    • C04B41/87—Ceramics
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
    • C04B41/91—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics involving the removal of part of the materials of the treated articles, e.g. etching
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/32—Carbides
    • 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 present invention relates to polycrystalline SiC compacts.
  • Polycrystalline SiC compacts have excellent mechanical strength properties, electrical properties, heat resistance, chemical stability, etc., and are used in various industrial applications.
  • polycrystalline SiC compacts are used in high-temperature and high-purity atmospheres, and their main uses include members constituting CVD reactors.
  • JP 2021-085092 A Japanese Patent Application Laid-Open No. 2021-134111 JP 2019-199078 A Japanese Patent Application Laid-Open No. 2020-33239
  • the polycrystalline SiC molded body When used for such applications, for example, the polycrystalline SiC molded body is required to have a lower thermal conductivity in order to easily maintain a high temperature once heated. At the same time, for the purpose of making deformation of the member difficult, it is required to have higher mechanical strength, specifically, higher breaking strength.
  • Patent Document 1 a method for producing a silicon carbide polycrystalline film with few voids for the purpose of suppressing an increase in electrical resistance
  • Patent Document 2 a porous body containing voids and exhibiting excellent thermal shock resistance
  • Patent Document 3 voids are introduced into the base material SiC, such as ceramic compacts for sintering (Patent Document 3) for the purpose of reducing residual stress, to exhibit a predetermined effect. Proposed.
  • a void when a void is introduced, the void becomes a starting point of fracture, resulting in a decrease in mechanical strength.
  • Patent Document 4 As a means for reducing the thermal conductivity of a polycrystalline SiC compact, there is known a means for restricting the orientation of the structure in a specific direction with respect to the thickness direction (Patent Document 4).
  • Patent Document 4 a means for restricting the orientation of the structure in a specific direction with respect to the thickness direction
  • an object of the present invention is to provide a technique that can reduce the thermal conductivity in the direction normal to the main surface of a polycrystalline SiC molded body without reducing the mechanical strength.
  • one embodiment of the present invention is a polycrystalline SiC molded body composed of a first structure and a second structure, wherein the polycrystalline SiC molded body is plate-shaped and has a substantially planar main surface.
  • the first structure is polycrystalline SiC having a 3C type crystal structure
  • the second structure is a structure different from the first structure
  • the first structure is the A structure in which the (111) plane, the (200) plane, the (220) plane, or the (311) plane is oriented along the substantially normal direction of the main surface of the polycrystalline SiC compact, and
  • the area fraction of the structure of 1 is more than 0% and less than 50%, the average crystal grain size is 5 ⁇ m or less
  • the X-ray diffraction pattern on the main surface shows SiC (111) plane, SiC (200) plane, SiC A polycrystalline SiC compact in which the ratio of the X-ray diffraction peak intensity of the SiC (111) plane to the sum of the X-ray diffraction peak intensities of the (220) plane and the SiC (311) plane is 0.8 or more.
  • one embodiment of the present invention is the polycrystalline SiC molded body described above, wherein the cross section includes 0 or more and less than 40 voids per 1 cm 2 whose circumscribing circles have a diameter of more than 1 ⁇ m. Further, one embodiment of the present invention is the polycrystalline SiC molded body, wherein the thermal conductivity in the normal direction of the main surface is 90 to 130 W/m ⁇ K. Further, one embodiment of the present invention is the polycrystalline SiC compact having a three-point bending strength of 560 MPa or more and a Young's modulus of 250 GPa or more according to JIS R 1601.
  • a technique is provided that can reduce the thermal conductivity in the direction normal to the main surface of the polycrystalline SiC molded body without reducing the mechanical strength.
  • FIG. 1 is a schematic diagram showing an example of the shape of a polycrystalline SiC compact.
  • FIG. 2 is a schematic diagram showing an example of a cross section parallel to the normal D to the main surface of the polycrystalline SiC compact 1.
  • FIG. 3 is a schematic diagram showing an example of a system for manufacturing a polycrystalline SiC compact.
  • FIG. 4 is data showing an example of an EBSD orientation map in the direction normal to the main surface of a polycrystalline SiC compact.
  • FIG. 1 is a schematic diagram showing an example of the shape of a polycrystalline SiC molded body.
  • FIG. 2 is a schematic diagram showing an example of a cross section parallel to the normal D to the main surface of the polycrystalline SiC compact 1.
  • the polycrystalline SiC compact will be described below with reference to FIGS. 1 and 2.
  • FIG. A polycrystalline SiC compact 1 according to the present embodiment is plate-shaped and has a substantially planar main surface 2 .
  • the "plate-like" is preferably columnar having a height, that is, a thickness, and the shape of the upper base and/or the lower base is preferably disc-like.
  • the “main surface” 2 of the polycrystalline SiC molded body 1 refers to the upper and/or lower base of the columnar shape.
  • the thickness of the polycrystalline SiC compact is, for example, 0.1 to 5.0 mm, preferably 0.2 to 3.0 mm.
  • a polycrystalline SiC compact consists of a "first structure” 3 and a “second structure” 4.
  • the "first organization” 3 and the “second organization” 4 are organizations with different structures.
  • the “first texture” is polycrystalline SiC having a 3C type crystal structure, and the (111) plane of SiC having a 3C type crystal structure along the direction of the approximate normal to the main surface of the polycrystalline SiC compact, It is a structure in which the (200) plane, (220) plane or (311) plane is oriented.
  • the “substantially normal direction” is a direction within a range of ⁇ 10° from the normal D to the main surface 2 of the polycrystalline SiC compact 1 .
  • the "second texture” is polycrystalline SiC having a 3C type crystal structure or polycrystalline SiC having a 4H type crystal structure or a 6H type crystal structure.
  • the second structure is polycrystalline SiC having a 3C type crystal structure
  • the second structure is SiC having a 3C type crystal structure along the substantially normal direction of the main surface of the polycrystalline SiC compact.
  • the (111) plane, (200) plane, (220) plane, or (311) plane of is a texture in which none of the planes is oriented.
  • the area fraction of the first structure on the main surface is more than 0% and less than 50%.
  • the area fraction of the first tissue is more preferably greater than 0% and less than 40%.
  • the "area fraction of the first structure" can be obtained by the method described in Examples below.
  • the average crystal grain size of the polycrystalline SiC compact is 5 ⁇ m or less.
  • the average grain size is preferably 0.5-5 ⁇ m, more preferably 0.1-3 ⁇ m.
  • average crystal grain size is a value calculated from the size of a region observed as a single region by an EBSD (Electron Backscatter Diffraction) method.
  • the “single region” is a region having the same crystal structure and the same orientation with respect to the main surface 2 .
  • Average crystal grain size is a value obtained by multiplying the area of the above single region by the total area of the observation region divided by the area of the single region in the entire region observed by the EBSD method. is obtained for all single regions and refers to their total value.
  • the polycrystalline SiC compact 1 has an X-ray diffraction peak intensity ratio of the SiC (111) plane of 0.8 or more in the X-ray diffraction pattern on the main surface 2 .
  • the ratio of the X-ray diffraction peak intensity of the SiC (111) plane is a value obtained based on the X-ray diffraction pattern obtained by measuring the main surface. It represents the ratio of the X-ray diffraction peak intensity of the SiC (111) plane to the sum of the diffraction peak intensities of the SiC (220) plane and the SiC (311) plane.
  • the ratio of the X-ray diffraction peak intensity of the SiC (111) plane differs depending on the position within the main surface 2, the value at the center of the main surface is the X-ray diffraction peak of the SiC (111) plane.
  • the X-ray diffraction peak intensity ratio of the SiC (111) plane is preferably 0.9 or more.
  • polycrystalline SiC molding having low thermal conductivity in the normal direction to the main surface without reducing the number of voids and impairing the mechanical strength you get a body
  • voids per 1 cm 2 there are 0 or more and less than 40 voids per 1 cm 2 , preferably 0 or more and less than 20 voids per 1 cm 2 , and more preferably 0 or more and less than 20 voids whose circumscribing circle diameter is more than 1 ⁇ m. is 0 or more and less than 5 per 1 cm 2 , and a polycrystalline SiC molded body 1 having a cross section parallel to the normal line D is obtained.
  • the term "circumscribed circle” used with respect to voids means an imaginary circle circumscribing the voids observed in the cross-section of the polycrystalline SiC compact.
  • the three-point bending strength of the polycrystalline SiC molded body 1 according to JIS R 1601 can be, for example, 560 MPa or more.
  • the Young's modulus of the polycrystalline SiC compact 1 can be made 250 GPa or more.
  • the thermal conductivity of the polycrystalline SiC compact can be set to, for example, 90 to 130 W/m ⁇ K.
  • it is preferably 100 to 130 W/m ⁇ K.
  • Polycrystalline SiC compacts are suitable for applications where they are used in high-temperature and high-purity atmospheres. Such uses include CVD reactor components and the like.
  • FIG. 3 is a schematic diagram showing an example of a manufacturing system used in the method for manufacturing a polycrystalline SiC compact according to this embodiment.
  • This manufacturing system 5 is provided with a CVD reactor 6 and a mixing section 7 .
  • the mixing unit 7 the carrier gas output from the carrier gas container 8, the raw material gas output from the raw material gas container 9 and serving as the SiC raw material, and the nitrogen-containing gas output from the nitrogen-containing gas container 10 are mixed, A mixed gas is produced.
  • the nitrogen-containing gas is not necessarily required, and can be omitted when the polycrystalline SiC compact is not doped with nitrogen.
  • the mixed gas After passing through the mixing section 7 , the mixed gas passes through the flow meter 11 and is introduced into the CVD reactor 6 through the gas introduction nozzle 12 .
  • a support substrate 13 is positioned within the CVD reactor 6 .
  • the support substrate 13 can preferably be made of graphite.
  • the support substrate 13 is preferably disc-shaped.
  • the support substrate 13 is heated during operation.
  • a mixed gas containing a nitrogen-containing gas is introduced, a nitrogen-doped polycrystalline SiC film is obtained.
  • the polycrystalline SiC film obtained in the above steps is separated from the support substrate 13 after the film formation is completed, and if necessary, the surface separated from the support substrate 13 and / or the surface facing the surface is mainly It is plane-ground so that it may become the surface 2. Thus, a polycrystalline SiC compact 1 is obtained.
  • the polycrystalline SiC compact according to the present embodiment is obtained by controlling the film formation conditions such as the reaction temperature of the CVD reaction, the concentration of the raw material gas in the mixed gas, the pressure in the CVD reactor 6, and the like. 1 can be obtained.
  • the above manufacturing method can be applied regardless of whether it is a hot wall method or a cold wall method.
  • a hot wall method for example, by adopting the cold-wall type CVD reactor 6 , decomposition of the raw material gas in the gas phase other than the supporting substrate 13 is suppressed in the CVD reactor 6 . As a result, the crystal grain size of the polycrystalline SiC film can be reduced.
  • a heating method of the support base material 13 in the CVD reactor 6 is not particularly limited. Any heating method, for example, resistance heating, induction heating, or laser heating, can be employed.
  • the heating temperature (the temperature of the support base material 13) when forming the polycrystalline SiC film on the support base material 13 is, for example, 1200 to 1400.degree.
  • the heating temperature during formation of the polycrystalline SiC film affects the crystal structure of the obtained polycrystalline SiC film.
  • the furnace wall and heat insulating material in the CVD reactor 6 must be at a temperature (e.g., 1000° C. or less, preferably 700° C. or less) at which SiC and decomposition products of the source gas do not accumulate. is preferred.
  • each flow rate of the gas has a predetermined ratio based on the flow rate of the raw material gas.
  • the ratio of (source gas flow rate):(carrier gas flow rate):(nitrogen-containing gas flow rate) is preferably set to 1:(1.5 to 2.9):3.
  • the nitrogen-containing gas it is preferable to set the ratio of (raw material gas flow rate):(carrier gas flow rate) to 1:(1.5 to 4).
  • the carrier gas flow rate is 1.5 times or more with respect to the raw material gas flow rate.
  • a raw material gas serving as a supply source of SiC may be a one-component system (a gas containing Si and C) or a two-component system (a gas containing Si and a gas containing C).
  • one-component raw material gases include trichloromethylsilane, trichlorophenylsilane, dichloromethylsilane, dichlorodimethylsilane, and chlorotrimethylsilane.
  • the two-component raw material gas include a mixture of a silane-containing gas such as trichlorosilane and monosilane, and a hydrocarbon gas.
  • the flow rate of the raw material gas is, for example, 1 to 50 L/min. , preferably 2 to 30 L/min. , more preferably 3 to 20 L/min. is.
  • a carrier gas used during film formation is not particularly limited, and hydrogen gas or the like can be used, for example.
  • the carrier gas flow rate is, for example, 5 to 100 L/min. , preferably 10 to 70 L/min. is.
  • a nitrogen-containing gas is used. Any nitrogen-containing gas may be used as long as it can dope the polycrystalline SiC film with nitrogen.
  • nitrogen gas is used as the nitrogen-containing gas.
  • the flow rate of the nitrogen-containing gas is, for example, 5-100 L/min. , preferably 10 to 60 L/min. is.
  • the pressure inside the CVD reactor 6 during the formation of the polycrystalline SiC film is, for example, 50 to 150 kPa, preferably 70 to 110 kPa.
  • Example 1 As a CVD reactor, a polycrystalline SiC compact manufacturing system 5 having the configuration shown in FIG. 3 was prepared. A graphite substrate having a diameter of 230 mm and a thickness of 5 mm was prepared as the supporting substrate 13 and placed in the CVD reactor 6 .
  • Example 1 in Table 1 a polycrystalline SiC film was formed on the support substrate 13 .
  • MTS trimethylsilane
  • H 2 gas was used as a carrier gas.
  • N 2 gas was used as the nitrogen-containing gas.
  • a raw material gas, a carrier gas, and a nitrogen-containing gas were mixed in the mixing section 7 to generate a mixed gas.
  • a mixed gas was introduced into the CVD reactor 6 .
  • the amount of the mixed gas introduced, that is, the mixed gas flow rate is a value measured by the flow meter 11 .
  • the amounts of MTS gas, H 2 gas, and N 2 gas supplied were as described in Example 1 in Table 1, respectively.
  • the concentration of each gas in the mixed gas was set as described in Example 1 in Table 1.
  • the reaction temperature that is, the temperature of the supporting substrate 13) was 1340°C.
  • the graphite base material was removed from the polycrystalline SiC film to obtain a polycrystalline SiC compact with a diameter of 215 mm and a thickness of 3 mm. Then, the obtained polycrystalline SiC molded body was ground to a smooth surface on the surface separated from the graphite substrate and/or the surface opposite to the surface. Further, the polycrystalline SiC molded body was processed so as to have a predetermined diameter. As a result, a polycrystalline SiC compact with a diameter of 210 mm and a thickness of 2 mm was obtained. This was used as a polycrystalline SiC compact according to Example 1.
  • Example 2-6 and Comparative Examples 1-6 A polycrystalline SiC film was formed in the same manner as in Example 1. Here, the conditions for forming the polycrystalline SiC film were changed to the conditions shown in Tables 1 and 2.
  • EBSD orientation maps were measured in the ⁇ 10° direction (hereinafter referred to as the ND direction) of the main surface normal direction of the polycrystalline SiC molded bodies obtained in Examples 1 to 6 and Comparative Examples 1 to 6. bottom.
  • the EBSD orientation map the (111) plane, (200) plane, (220) plane or (311) plane of the 3C type crystal structure SiC is oriented along the ND direction. ” was extracted. Based on the extraction results, the area fraction (%) of the “first structure” in the measurement area of 100 ⁇ m ⁇ 100 ⁇ m was obtained.
  • the measurement conditions for the EBSD orientation map were as follows. Pretreatment: Mechanical polishing, carbon deposition equipment: FE-SEM SU-70 manufactured by Hitachi High-Tech DigiView manufactured by EBSD TSL Solutions Measurement conditions: Voltage: 20 kV Radial angle: 70° Measurement area: 100 ⁇ m ⁇ 100 ⁇ m Measurement interval: 0.03 ⁇ m Evaluation target crystal system: 3C type SiC (space group 216)
  • the diffraction angle 2 ⁇ was 20.0 to 80.0 deg. is used as the background correction value, and the diffraction angle 2 ⁇ is 35.3 to 36.0 deg. was obtained as the diffraction peak intensity of the (111) plane of the 3C-type crystal structure SiC. Similarly, when the diffraction angle 2 ⁇ is 41.1 to 41.8 deg. was obtained as the diffraction peak intensity of the SiC (200) plane. Similarly, when the diffraction angle 2 ⁇ is 59.7 to 60.3 deg. was obtained as the diffraction peak intensity of the SiC (220) plane. Similarly, when the diffraction angle 2 ⁇ is 71.5 to 72.3 deg.
  • the diffraction peak intensity of the SiC (311) plane was obtained as the diffraction peak intensity of the SiC (311) plane. Then, the sum of the diffraction peak intensities of the SiC (111) plane, the SiC (200) plane, the SiC (220) plane, and the SiC (311) plane was obtained. Furthermore, the ratio of the diffraction peak intensity of the SiC (111) plane to the total value was obtained as the ratio of the X-ray diffraction peak intensity of the SiC (111) plane.
  • thermophysical property measuring device Thermo Wave Analyzer TA Method: Periodic heating radiation thermometry
  • Environmental temperature Room temperature
  • Tables 1 and 2 show the results.
  • the polycrystalline SiC molded bodies according to Examples 1 to 6 have an average crystal grain size of 5 ⁇ m or less, an area fraction of the first structure of 22 to 48%, and an X-ray diffraction of the SiC (111) plane The peak intensity ratio was 80% or greater (ie, 0.8 or greater).
  • Examples 1-6 were superior to Comparative Examples 1-6 in 3-point bending strength, Young's modulus and thermal conductivity according to JIS R 1601.

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Abstract

A polycrystalline SiC molded body comprising a first structure and a second structure, wherein the polycrystalline SiC molded body is plate-shaped and has a substantially flat main surface, the first structure is a polycrystalline SiC having a 3C-type crystal structure, the second structure is different from the first structure, in the first structure, the (111) plane, (200) plane, (220) plane, or (311) plane is oriented along a direction substantially normal to the main surface of the polycrystalline SiC molded body, the area fraction of the first structure in the main surface is more than 0% and less than 50%, the average crystal grain size is 5 μm or less, and in the X-ray diffraction pattern on the main surface, the ratio of the X-ray diffraction peak intensity of the SiC (111) plane to the total X-ray diffraction peak intensity of SiC (111) plane, SiC (200) plane, SiC (220) plane, and SiC (311) plane is 0.8 or more.

Description

多結晶ＳｉＣ成形体Polycrystalline SiC compact
　本発明は、多結晶ＳｉＣ成形体に関する。 The present invention relates to polycrystalline SiC compacts.
　多結晶ＳｉＣ成形体は、機械強度特性、電気特性、耐熱性、化学安定性などに優れ、様々な産業用途で使用されている。例えば、多結晶ＳｉＣ成形体は、高温雰囲気、且つ高純度雰囲気において使用され、主な用途として、ＣＶＤ反応炉を構成する部材などが挙げられる。 Polycrystalline SiC compacts have excellent mechanical strength properties, electrical properties, heat resistance, chemical stability, etc., and are used in various industrial applications. For example, polycrystalline SiC compacts are used in high-temperature and high-purity atmospheres, and their main uses include members constituting CVD reactors.
特開２０２１－０８５０９２号公報JP 2021-085092 A 特開２０２１－１３４１１１号公報Japanese Patent Application Laid-Open No. 2021-134111 特開２０１９－１９９０７８号公報JP 2019-199078 A 特開２０２０－３３２３９号公報Japanese Patent Application Laid-Open No. 2020-33239
　このような用途に使用される場合、例えば、多結晶ＳｉＣ成形体には、一旦加熱された高温状態を保ち易くする目的で、より低い熱伝導率を有していることが求められる。同時に、その部材の変形をし難くする目的で、より高い機械強度、具体的には高い破壊強度を有していることが求められる。 When used for such applications, for example, the polycrystalline SiC molded body is required to have a lower thermal conductivity in order to easily maintain a high temperature once heated. At the same time, for the purpose of making deformation of the member difficult, it is required to have higher mechanical strength, specifically, higher breaking strength.
　先行技術によれば、電気抵抗増大を抑制することを目的とする空隙の少ない炭化ケイ素多結晶膜の製造方法（特許文献１）、空隙を含み優れた耐熱衝撃特性を示す多孔質体（特許文献２）、残留応力の低下させることを目的とした空隙の少ない焼結用セラミックス成形体（特許文献３）など空隙（ボイド）を母材であるＳｉＣに導入して所定の効果を発現させる発明が提案されている。しかしながら、空隙を導入した場合、その空隙が破壊の起点となり、機械強度が低下してしまう。また、多結晶ＳｉＣ成形体の熱伝導率を低下させるための手段として、その組織の配向性を厚さ方向に対して特定の方向に規制させる手段が知られている（特許文献４）。しかしながら、材料力学の観点から、材料内部の結晶質組織が一様に配向した場合、特定方向の応力に対する機械強度は優れる一方で、他の特定方向の応力に対する機械強度は極端に低くなってしまう。 According to the prior art, a method for producing a silicon carbide polycrystalline film with few voids for the purpose of suppressing an increase in electrical resistance (Patent Document 1), a porous body containing voids and exhibiting excellent thermal shock resistance (Patent Document 1) 2) There are inventions in which voids are introduced into the base material SiC, such as ceramic compacts for sintering (Patent Document 3) for the purpose of reducing residual stress, to exhibit a predetermined effect. Proposed. However, when a void is introduced, the void becomes a starting point of fracture, resulting in a decrease in mechanical strength. Also, as a means for reducing the thermal conductivity of a polycrystalline SiC compact, there is known a means for restricting the orientation of the structure in a specific direction with respect to the thickness direction (Patent Document 4). However, from the viewpoint of material mechanics, when the crystalline structure inside the material is uniformly oriented, the mechanical strength against stress in a specific direction is excellent, but the mechanical strength against stress in other specific directions is extremely low. .
　そこで、本発明の課題は、機械的強度を低下させることなく、多結晶ＳｉＣ成形体の主面に対する法線方向の熱伝導率を低下させることのできる技術を提供することにある。 Therefore, an object of the present invention is to provide a technique that can reduce the thermal conductivity in the direction normal to the main surface of a polycrystalline SiC molded body without reducing the mechanical strength.
　本願発明者らは、検討の結果、下記の手段により、上記課題が解決できることを見出した。
　すなわち、本願発明の一実施形態は、第１の組織と第２の組織とからなる多結晶ＳｉＣ成形体であって、前記多結晶ＳｉＣ成形体は、板状であって、略平面の主面を有し、前記第１の組織は、３Ｃ型結晶構造を有する多結晶ＳｉＣであって、前記第２の組織は、前記第１の組織と異なる組織であり、前記第１の組織は、前記多結晶ＳｉＣ成形体の前記主面の略法線方向に沿って、（１１１）面、（２００）面、（２２０）面又は（３１１）面が配向した組織であり、前記主面における前記第１の組織の面積分率が０％超５０％未満であり、平均結晶粒径が５μｍ以下であり、前記主面におけるＸ線回折パターンにおいて、ＳｉＣ（１１１）面、ＳｉＣ（２００）面、ＳｉＣ（２２０）面、およびＳｉＣ（３１１）面のＸ線回折ピーク強度の合計に対する、ＳｉＣ（１１１）面のＸ線回折ピーク強度の比率が、０．８以上である、多結晶ＳｉＣ成形体である。
　また、本願発明の一実施形態は、断面が、外接する円の直径が１μｍ超である空隙を、１ｃｍ2当たりに０個以上４０個未満含む、上記多結晶ＳｉＣ成形体である。
　また、本願発明の一実施形態は、前記主面の法線方向における熱伝導率が９０～１３０Ｗ／ｍ・Ｋである、上記多結晶ＳｉＣ成形体である。
　また、本願発明の一実施形態は、ＪＩＳ　Ｒ　１６０１における３点曲げ強度が５６０ＭＰａ以上、且つヤング率が２５０ＧＰａ以上である、上記多結晶ＳｉＣ成形体である。 As a result of studies, the inventors of the present application have found that the above problems can be solved by the following means.
That is, one embodiment of the present invention is a polycrystalline SiC molded body composed of a first structure and a second structure, wherein the polycrystalline SiC molded body is plate-shaped and has a substantially planar main surface. wherein the first structure is polycrystalline SiC having a 3C type crystal structure, the second structure is a structure different from the first structure, and the first structure is the A structure in which the (111) plane, the (200) plane, the (220) plane, or the (311) plane is oriented along the substantially normal direction of the main surface of the polycrystalline SiC compact, and The area fraction of the structure of 1 is more than 0% and less than 50%, the average crystal grain size is 5 μm or less, and the X-ray diffraction pattern on the main surface shows SiC (111) plane, SiC (200) plane, SiC A polycrystalline SiC compact in which the ratio of the X-ray diffraction peak intensity of the SiC (111) plane to the sum of the X-ray diffraction peak intensities of the (220) plane and the SiC (311) plane is 0.8 or more. .
Further, one embodiment of the present invention is the polycrystalline SiC molded body described above, wherein the cross section includes 0 or more and less than 40 voids per 1 cm 2 whose circumscribing circles have a diameter of more than 1 μm.
Further, one embodiment of the present invention is the polycrystalline SiC molded body, wherein the thermal conductivity in the normal direction of the main surface is 90 to 130 W/m·K.
Further, one embodiment of the present invention is the polycrystalline SiC compact having a three-point bending strength of 560 MPa or more and a Young's modulus of 250 GPa or more according to JIS R 1601.
　本願発明によれば、機械的強度を低下させることなく、多結晶ＳｉＣ成形体の主面に対する法線方向の熱伝導率を低下させることのできる技術が提供される。 According to the present invention, a technique is provided that can reduce the thermal conductivity in the direction normal to the main surface of the polycrystalline SiC molded body without reducing the mechanical strength.
図１は、多結晶ＳｉＣ成形体の形状の例を示す模式図である。FIG. 1 is a schematic diagram showing an example of the shape of a polycrystalline SiC compact. 図２は、多結晶ＳｉＣ成形体１の主面に対する法線Ｄに平行な断面の例を示す模式図である。FIG. 2 is a schematic diagram showing an example of a cross section parallel to the normal D to the main surface of the polycrystalline SiC compact 1. As shown in FIG. 図３は、多結晶ＳｉＣ成形体の製造システムの一例を示す概略図である。FIG. 3 is a schematic diagram showing an example of a system for manufacturing a polycrystalline SiC compact. 図４は、多結晶ＳｉＣ成形体の主面法線方向におけるＥＢＳＤ方位マップの一例を示すデータである。FIG. 4 is data showing an example of an EBSD orientation map in the direction normal to the main surface of a polycrystalline SiC compact.
１：多結晶ＳｉＣ成形体
　図１は、多結晶ＳｉＣ成形体の形状の例を示す模式図である。図２は、多結晶ＳｉＣ成形体１の主面に対する法線Ｄに平行な断面の例を示す模式図である。以下図１及び図２を参照し多結晶ＳｉＣ成形体について説明する。
　本実施形態に係る多結晶ＳｉＣ成形体１は、板状であって、略平面の主面２を有している。ここで、「板状」は、高さ、すなわち厚さを有する柱状であることが好ましく、その上底及び／又はその下底の形状は、好ましくは円板状である。このような板状である場合、多結晶ＳｉＣ成形体１の「主面」２とは、柱状の上底及び／又は下底を指している。この場合、多結晶ＳｉＣ成形体の厚さは、例えば、０．１～５．０ｍｍ、好ましくは０．２～３．０ｍｍである。 1: Polycrystalline SiC Molded Body FIG. 1 is a schematic diagram showing an example of the shape of a polycrystalline SiC molded body. FIG. 2 is a schematic diagram showing an example of a cross section parallel to the normal D to the main surface of the polycrystalline SiC compact 1. As shown in FIG. The polycrystalline SiC compact will be described below with reference to FIGS. 1 and 2. FIG.
A polycrystalline SiC compact 1 according to the present embodiment is plate-shaped and has a substantially planar main surface 2 . Here, the "plate-like" is preferably columnar having a height, that is, a thickness, and the shape of the upper base and/or the lower base is preferably disc-like. In the case of such a plate-like shape, the “main surface” 2 of the polycrystalline SiC molded body 1 refers to the upper and/or lower base of the columnar shape. In this case, the thickness of the polycrystalline SiC compact is, for example, 0.1 to 5.0 mm, preferably 0.2 to 3.0 mm.
　多結晶ＳｉＣ成形体は、「第１の組織」３と「第２の組織」４とからなっている。ここで、「第１の組織」３と「第２の組織」４とは、構造が相違する組織である。 A polycrystalline SiC compact consists of a "first structure" 3 and a "second structure" 4. Here, the "first organization" 3 and the "second organization" 4 are organizations with different structures.
　「第１の組織」は、３Ｃ型結晶構造を有する多結晶ＳｉＣであり、多結晶ＳｉＣ成形体の主面の略法線方向に沿って、３Ｃ型結晶構造を有するＳｉＣの（１１１）面、（２００）面、（２２０）面又は（３１１）面が配向した組織である。なお、本明細書において、「略法線方向」とは、多結晶ＳｉＣ成形体１の主面２に対する法線Dを中心として±１０°の範囲内の方向である。 The “first texture” is polycrystalline SiC having a 3C type crystal structure, and the (111) plane of SiC having a 3C type crystal structure along the direction of the approximate normal to the main surface of the polycrystalline SiC compact, It is a structure in which the (200) plane, (220) plane or (311) plane is oriented. In this specification, the “substantially normal direction” is a direction within a range of ±10° from the normal D to the main surface 2 of the polycrystalline SiC compact 1 .
　「第２の組織」は、３Ｃ型結晶構造を有する多結晶ＳｉＣ又は４Ｈ型結晶構造若しくは６Ｈ型結晶構造を有する多結晶ＳｉＣである。ここで、第２の組織が３Ｃ型結晶構造を有する多結晶ＳｉＣの場合、第２の組織は、多結晶ＳｉＣ成形体の主面の略法線方向に沿って、３Ｃ型結晶構造を有するＳｉＣの（１１１）面、（２００）面、（２２０）面又は（３１１）面のいずれもが配向していない組織である。 The "second texture" is polycrystalline SiC having a 3C type crystal structure or polycrystalline SiC having a 4H type crystal structure or a 6H type crystal structure. Here, when the second structure is polycrystalline SiC having a 3C type crystal structure, the second structure is SiC having a 3C type crystal structure along the substantially normal direction of the main surface of the polycrystalline SiC compact. The (111) plane, (200) plane, (220) plane, or (311) plane of is a texture in which none of the planes is oriented.
　主面における第１の組織の面積分率は、０％超５０％未満である。第１の組織の面積分率は、より好ましくは、０％超４０％未満である。ここで「第１の組織の面積分率」は、後述の実施例において説明する方法により、求めることができる。 The area fraction of the first structure on the main surface is more than 0% and less than 50%. The area fraction of the first tissue is more preferably greater than 0% and less than 40%. Here, the "area fraction of the first structure" can be obtained by the method described in Examples below.
　多結晶ＳｉＣ成形体の平均結晶粒径は、５μｍ以下である。平均結晶粒径は、好ましくは０．５～５μｍ、より好ましくは０．１～３μｍである。
　本明細書において、「平均結晶粒径」とは、ＥＢＳＤ（Ｅｌｅｃｔｒｏｎ　ｂａｃｋｓｃａｔｔｅｒ　ｄｉｆｆｒａｃｔｉｏｎ）法により、単一領域として観測される領域の大きさから算出される値である。ここで、「単一領域」とは、同一の結晶組織であって、主面２に対する同一の配向性を有する領域である。
　「平均結晶粒径」は、具体的に、ＥＢＳＤ法により観測された全領域内において、上記単一領域の面積にその単一領域の面積を観測領域の全面積で除した値を乗じた値を、全ての単一領域について求め、それらの合計値を指す。 The average crystal grain size of the polycrystalline SiC compact is 5 μm or less. The average grain size is preferably 0.5-5 μm, more preferably 0.1-3 μm.
As used herein, "average crystal grain size" is a value calculated from the size of a region observed as a single region by an EBSD (Electron Backscatter Diffraction) method. Here, the “single region” is a region having the same crystal structure and the same orientation with respect to the main surface 2 .
"Average crystal grain size" is a value obtained by multiplying the area of the above single region by the total area of the observation region divided by the area of the single region in the entire region observed by the EBSD method. is obtained for all single regions and refers to their total value.
　多結晶ＳｉＣ成形体１は、主面２におけるＸ線回折パターンにおいて、０．８以上のＳｉＣ（１１１）面のX線回折ピーク強度の比率を有するものである。ここで、ＳｉＣ（１１１）面のX線回折ピーク強度の比率とは、主面について測定して得られたＸ線回折パターンに基づき求められる値であり、ＳｉＣ（１１１）面、ＳｉＣ（２００）面、ＳｉＣ（２２０）面、およびＳｉＣ（３１１）面の回折ピーク強度の合計に対する、ＳｉＣ（１１１）面のＸ線回折ピーク強度の比率を表す。
　なお、主面２内の位置の違いにより、ＳｉＣ（１１１）面のX線回折ピーク強度の比率が異なる場合には、主面における中心部の値が、ＳｉＣ（１１１）面のX線回折ピーク強度の比率として採用される。
　ＳｉＣ（１１１）面のX線回折ピーク強度の比率は、好ましくは、０．９以上である。 The polycrystalline SiC compact 1 has an X-ray diffraction peak intensity ratio of the SiC (111) plane of 0.8 or more in the X-ray diffraction pattern on the main surface 2 . Here, the ratio of the X-ray diffraction peak intensity of the SiC (111) plane is a value obtained based on the X-ray diffraction pattern obtained by measuring the main surface. It represents the ratio of the X-ray diffraction peak intensity of the SiC (111) plane to the sum of the diffraction peak intensities of the SiC (220) plane and the SiC (311) plane.
In addition, when the ratio of the X-ray diffraction peak intensity of the SiC (111) plane differs depending on the position within the main surface 2, the value at the center of the main surface is the X-ray diffraction peak of the SiC (111) plane. Employed as a strength ratio.
The X-ray diffraction peak intensity ratio of the SiC (111) plane is preferably 0.9 or more.
　本実施形態によれば、上述のような組織構造を有していることにより、空隙が少なく、機械的強度を損なうことなく、主面に対する法線方向について低い熱伝導率を有する多結晶ＳｉＣ成形体が得られる。 According to the present embodiment, by having the structure as described above, polycrystalline SiC molding having low thermal conductivity in the normal direction to the main surface without reducing the number of voids and impairing the mechanical strength you get a body
　具体的には、本実施形態によれば、外接する円の直径が１μｍ超である空隙が１ｃｍ2当たりに０個以上４０個未満、好ましくは１ｃｍ2当たりに０個以上２０個未満、より好ましくは１ｃｍ2当たりに０個以上５個未満である、法線Ｄに平行な断面を有する多結晶ＳｉＣ成形体１が得られる。空隙に関して使用される「外接する円」という用語は、多結晶ＳｉＣ成形体の断面で観察される空隙に外接する仮想的な円を意味する。 Specifically, according to the present embodiment, there are 0 or more and less than 40 voids per 1 cm 2 , preferably 0 or more and less than 20 voids per 1 cm 2 , and more preferably 0 or more and less than 20 voids whose circumscribing circle diameter is more than 1 μm. is 0 or more and less than 5 per 1 cm 2 , and a polycrystalline SiC molded body 1 having a cross section parallel to the normal line D is obtained. The term "circumscribed circle" used with respect to voids means an imaginary circle circumscribing the voids observed in the cross-section of the polycrystalline SiC compact.
　本実施形態によれば、多結晶ＳｉＣ成形体１のＪＩＳ　Ｒ　１６０１における３点曲げ強度を、例えば５６０ＭＰａ以上にすることができる。また、多結晶ＳｉＣ成形体１のヤング率を、２５０ＧＰａ以上にすることができる。また、多結晶ＳｉＣ成形体の熱伝導率を、例えば９０～１３０Ｗ／ｍ・Ｋにすることができる。更に、ヤング率を高い値として可撓性を獲得する観点から、１００～１３０Ｗ／ｍ・Ｋとすることが好ましい。 According to this embodiment, the three-point bending strength of the polycrystalline SiC molded body 1 according to JIS R 1601 can be, for example, 560 MPa or more. Moreover, the Young's modulus of the polycrystalline SiC compact 1 can be made 250 GPa or more. Also, the thermal conductivity of the polycrystalline SiC compact can be set to, for example, 90 to 130 W/m·K. Furthermore, from the viewpoint of obtaining flexibility with a high Young's modulus, it is preferably 100 to 130 W/m·K.
　多結晶ＳｉＣ成形体は、高温雰囲気、かつ、高純度雰囲気において使用される用途において好適である。そのような用途として、ＣＶＤ反応炉の部材などが挙げられる。 Polycrystalline SiC compacts are suitable for applications where they are used in high-temperature and high-purity atmospheres. Such uses include CVD reactor components and the like.
２：多結晶ＳｉＣ成形体の製造方法
　上述した特性を有する多結晶ＳｉＣ成形体は、例えば、以下に説明する製造方法において、成膜条件などを調整することにより、得ることができる。以下に、本実施形態に係る多結晶ＳｉＣ成形体の製造方法について説明する。 2: Method for Manufacturing Polycrystalline SiC Molded Body A polycrystalline SiC molded body having the above-described properties can be obtained, for example, by adjusting the film forming conditions and the like in the manufacturing method described below. A method for manufacturing a polycrystalline SiC compact according to this embodiment will be described below.
　図３は、本実施形態に係る多結晶ＳｉＣ成形体の製造方法に使用される製造システムの一例を示す概略図である。この製造システム５には、ＣＶＤ反応炉６と、混合部７とが設けられている。混合部７では、キャリアガス容器８から出力されるキャリアガスと、原料ガス容器９から出力されＳｉＣの原料となる原料ガスと、窒素含有ガス容器１０から出力される窒素含有ガスとが混合され、混合ガスが生成される。
　ここで、窒素含有ガスは必ずしも必要ではなく、多結晶ＳｉＣ成形体中に窒素をドープしない場合には省略することもできる。 FIG. 3 is a schematic diagram showing an example of a manufacturing system used in the method for manufacturing a polycrystalline SiC compact according to this embodiment. This manufacturing system 5 is provided with a CVD reactor 6 and a mixing section 7 . In the mixing unit 7, the carrier gas output from the carrier gas container 8, the raw material gas output from the raw material gas container 9 and serving as the SiC raw material, and the nitrogen-containing gas output from the nitrogen-containing gas container 10 are mixed, A mixed gas is produced.
Here, the nitrogen-containing gas is not necessarily required, and can be omitted when the polycrystalline SiC compact is not doped with nitrogen.
　混合ガスは、混合部７を通過した後に、流量計１１を通過して、ガス導入ノズル１２を介してＣＶＤ反応炉６の内部に導入される。ＣＶＤ反応炉６内には、支持基材１３が配置される。支持基材１３は、好ましくは黒鉛で形成されることができる。支持基材１３は、好ましくは円板形状である。ＣＶＤ反応炉６において、支持基材１３は、運転時に加熱されるようになっている。混合ガスがＣＶＤ反応炉６内に導入されると、ＣＶＤ法によって、加熱された支持基材１３上に多結晶ＳｉＣ膜が成膜される。窒素含有ガスを混合した混合ガスを導入した場合には、窒素がドープされた多結晶ＳｉＣ膜が得られる。 After passing through the mixing section 7 , the mixed gas passes through the flow meter 11 and is introduced into the CVD reactor 6 through the gas introduction nozzle 12 . A support substrate 13 is positioned within the CVD reactor 6 . The support substrate 13 can preferably be made of graphite. The support substrate 13 is preferably disc-shaped. In the CVD reactor 6, the support substrate 13 is heated during operation. When the mixed gas is introduced into the CVD reactor 6, a polycrystalline SiC film is formed on the heated support substrate 13 by the CVD method. When a mixed gas containing a nitrogen-containing gas is introduced, a nitrogen-doped polycrystalline SiC film is obtained.
　上記の工程で得られた多結晶ＳｉＣ膜は、成膜完了後に支持基材１３から分離され、必要に応じて、支持基材１３と分離された面及び／又はその面と対向する面が主面２となるように、平面研削される。これにより、多結晶ＳｉＣ成形体１が得られる。 The polycrystalline SiC film obtained in the above steps is separated from the support substrate 13 after the film formation is completed, and if necessary, the surface separated from the support substrate 13 and / or the surface facing the surface is mainly It is plane-ground so that it may become the surface 2. Thus, a polycrystalline SiC compact 1 is obtained.
　上述の方法において、ＣＶＤ反応の反応温度、混合ガス中における原料ガスの濃度、ＣＶＤ反応炉６内の圧力等の成膜条件を所定に制御することにより、本実施形態に係る多結晶ＳｉＣ成形体１を得ることができる。 In the above-described method, the polycrystalline SiC compact according to the present embodiment is obtained by controlling the film formation conditions such as the reaction temperature of the CVD reaction, the concentration of the raw material gas in the mixed gas, the pressure in the CVD reactor 6, and the like. 1 can be obtained.
　上記の製造方法は、ホットウォール方式、コールドウォール方式のいずれを問わず適用することができる。例えば、コールドウォール方式のＣＶＤ反応炉６を採用することにより、ＣＶＤ反応炉６中において、支持基材１３以外の気相中での原料ガスの分解が抑制される。その結果、多結晶ＳｉＣ膜の結晶粒径を小さくさせることができる。
　ＣＶＤ反応炉６内における支持基材１３の加熱方式は、特に限定されない。加熱方式は、例えば、抵抗加熱、誘導加熱、レーザー加熱方式のいずれを問わず採用することができる。 The above manufacturing method can be applied regardless of whether it is a hot wall method or a cold wall method. For example, by adopting the cold-wall type CVD reactor 6 , decomposition of the raw material gas in the gas phase other than the supporting substrate 13 is suppressed in the CVD reactor 6 . As a result, the crystal grain size of the polycrystalline SiC film can be reduced.
A heating method of the support base material 13 in the CVD reactor 6 is not particularly limited. Any heating method, for example, resistance heating, induction heating, or laser heating, can be employed.
　多結晶ＳｉＣ膜の支持基材１３上への成膜時の加熱温度（支持基材１３の温度）は、例えば１２００～１４００℃である。多結晶ＳｉＣ膜の成膜時の加熱温度は、得られる多結晶ＳｉＣ膜の結晶構造に影響を与える。
　コールドウォール方式を適用した場合、ＣＶＤ反応炉６内の炉壁や断熱材は、ＳｉＣや原料ガスの分解生成物が堆積しない温度（例えば１０００℃以下、好ましくは７００℃以下）になっていることが好ましい。 The heating temperature (the temperature of the support base material 13) when forming the polycrystalline SiC film on the support base material 13 is, for example, 1200 to 1400.degree. The heating temperature during formation of the polycrystalline SiC film affects the crystal structure of the obtained polycrystalline SiC film.
When the cold wall method is applied, the furnace wall and heat insulating material in the CVD reactor 6 must be at a temperature (e.g., 1000° C. or less, preferably 700° C. or less) at which SiC and decomposition products of the source gas do not accumulate. is preferred.
　混合ガス中の各ガス成分の濃度、すなわちキャリアガス容器８から出力されるキャリアガスと、原料ガス容器９から出力されＳｉＣの原料となる原料ガスと、窒素含有ガス容器１０から出力される窒素含有ガスの各流量は、原料ガスの流量を基準として所定の比率とすることが好ましい。例えば、（原料ガス流量）：（キャリアガス流量）：（窒素含有ガス流量）の比は、１：（１．５～２．９）：３となるように設定することが好ましい。また、窒素含有ガスを混合しない場合には、（原料ガス流量）：（キャリアガス流量）の比は、１：（１．５～４）と設定することが好ましい。
　特に、多結晶ＳｉＣ膜内に空隙（ポア）を過剰に発生させないためには（すなわち、多結晶ＳｉＣ膜の断面が、外接する円の直径が１μｍ超である空隙を、１ｃｍ2当たりに４０個以上含まないためには）、原料ガス流量に対するキャリアガス流量は、１．５倍以上であることが好ましい。 The concentration of each gas component in the mixed gas, that is, the carrier gas output from the carrier gas container 8, the raw material gas output from the raw material gas container 9 and serving as the SiC raw material, and the nitrogen-containing gas output from the nitrogen-containing gas container 10 It is preferable that each flow rate of the gas has a predetermined ratio based on the flow rate of the raw material gas. For example, the ratio of (source gas flow rate):(carrier gas flow rate):(nitrogen-containing gas flow rate) is preferably set to 1:(1.5 to 2.9):3. When the nitrogen-containing gas is not mixed, it is preferable to set the ratio of (raw material gas flow rate):(carrier gas flow rate) to 1:(1.5 to 4).
In particular, in order not to generate an excessive number of pores in the polycrystalline SiC film (that is, the cross section of the polycrystalline SiC film has 40 pores per 1 cm 2 , the diameter of the circumscribing circle of which exceeds 1 μm). In order not to include the above, it is preferable that the carrier gas flow rate is 1.5 times or more with respect to the raw material gas flow rate.
　ＳｉＣの供給源となる原料ガスは、１成分系（Ｓｉ及びＣを含むガス）でも、２成分系（Ｓｉを含むガスとＣを含むガス）を使用してもよい。
　例えば、１成分系の原料ガスとしては、トリクロロメチルシラン、トリクロロフェニルシラン、ジクロロメチルシラン、ジクロロジメチルシラン、及びクロロトリメチルシラン等を挙げることができる。また２成分系の原料ガスとしては、トリクロロシラン、及びモノシラン等のシラン含有ガスと、炭化水素ガスとの混合物等を挙げる事ができる。 A raw material gas serving as a supply source of SiC may be a one-component system (a gas containing Si and C) or a two-component system (a gas containing Si and a gas containing C).
For example, one-component raw material gases include trichloromethylsilane, trichlorophenylsilane, dichloromethylsilane, dichlorodimethylsilane, and chlorotrimethylsilane. Examples of the two-component raw material gas include a mixture of a silane-containing gas such as trichlorosilane and monosilane, and a hydrocarbon gas.
　原料ガスの流量は、例えば、１～５０Ｌ／ｍｉｎ．、好ましくは２～３０Ｌ／ｍｉｎ．、より好ましくは３～２０Ｌ／ｍｉｎ．である。 　The flow rate of the raw material gas is, for example, 1 to 50 L/min. , preferably 2 to 30 L/min. , more preferably 3 to 20 L/min. is.
　成膜時に使用されるキャリアガスは、特に限定されるものではなく、例えば、水素ガス等を用いることができる。
　キャリアガスの流量は、例えば、５～１００Ｌ／ｍｉｎ．、好ましくは１０～７０Ｌ／ｍｉｎ．である。 A carrier gas used during film formation is not particularly limited, and hydrogen gas or the like can be used, for example.
The carrier gas flow rate is, for example, 5 to 100 L/min. , preferably 10 to 70 L/min. is.
　窒素をドープする場合には、既述のように、窒素含有ガスが使用される。窒素含有ガスとしては、窒素を多結晶ＳｉＣ膜にドープすることができるものであればよい。例えば、窒素ガスが、窒素含有ガスとして使用される。
　窒素含有ガスの流量は、例えば、５～１００Ｌ／ｍｉｎ．、好ましくは１０～６０Ｌ／ｍｉｎ．である。 When doping with nitrogen, as already mentioned, a nitrogen-containing gas is used. Any nitrogen-containing gas may be used as long as it can dope the polycrystalline SiC film with nitrogen. For example, nitrogen gas is used as the nitrogen-containing gas.
The flow rate of the nitrogen-containing gas is, for example, 5-100 L/min. , preferably 10 to 60 L/min. is.
　多結晶ＳｉＣ膜の成膜時におけるＣＶＤ反応炉６内の圧力は、例えば５０～１５０ｋＰａ、好ましくは７０～１１０ｋＰａである。 The pressure inside the CVD reactor 6 during the formation of the polycrystalline SiC film is, for example, 50 to 150 kPa, preferably 70 to 110 kPa.
　以下、本発明の一実施形態についてより詳しく説明するため、本発明者らによって行われた実施例について説明する。ただし、本発明は、以下の実施例に限定して解釈されるべきものでは無い。 In the following, examples performed by the present inventors will be described in order to describe one embodiment of the present invention in more detail. However, the present invention should not be construed as being limited to the following examples.
（実施例１）
　ＣＶＤ反応炉として、図３に示す構成の多結晶ＳｉＣ成形体の製造システム５を用意した。また、支持基材１３として、直径２３０ｍｍ、厚さ５ｍｍの黒鉛基材を準備し、ＣＶＤ反応炉６内に配置した。 (Example 1)
As a CVD reactor, a polycrystalline SiC compact manufacturing system 5 having the configuration shown in FIG. 3 was prepared. A graphite substrate having a diameter of 230 mm and a thickness of 5 mm was prepared as the supporting substrate 13 and placed in the CVD reactor 6 .
　次いで、表１中の実施例１に記載の条件で、支持基材１３上へ多結晶ＳｉＣ膜を成膜した。具体的には、原料ガスとしてトリメチルシラン（以下ＭＴＳという。）ガスを用いた。キャリアガスとして、Ｈ2ガスを用いた。窒素含有ガスとして、Ｎ2ガスを用いた。原料ガス、キャリアガス、および窒素含有ガスを混合部７において混合し、混合ガスを生成した。混合ガスをＣＶＤ反応炉６内に導入した。混合ガスの導入量、すなわち混合ガス流量は、流量計１１により測定される値である。また、ＭＴＳガス、Ｈ2ガス、およびＮ2ガスの供給量は、それぞれ、表１中の実施例１に記載の通りとした。混合ガス中の各ガスの濃度は、表１中の実施例１に記載のように設定した。反応温度（すなわち支持基材１３の温度）は、１３４０℃であった。 Then, under the conditions described in Example 1 in Table 1, a polycrystalline SiC film was formed on the support substrate 13 . Specifically, trimethylsilane (hereinafter referred to as MTS) gas was used as the raw material gas. H 2 gas was used as a carrier gas. N 2 gas was used as the nitrogen-containing gas. A raw material gas, a carrier gas, and a nitrogen-containing gas were mixed in the mixing section 7 to generate a mixed gas. A mixed gas was introduced into the CVD reactor 6 . The amount of the mixed gas introduced, that is, the mixed gas flow rate is a value measured by the flow meter 11 . Also, the amounts of MTS gas, H 2 gas, and N 2 gas supplied were as described in Example 1 in Table 1, respectively. The concentration of each gas in the mixed gas was set as described in Example 1 in Table 1. The reaction temperature (that is, the temperature of the supporting substrate 13) was 1340°C.
　支持基材１３上に多結晶ＳｉＣ膜が厚さ３ｍｍ成膜されたときに、成膜を終了した。 When the polycrystalline SiC film was formed on the supporting substrate 13 with a thickness of 3 mm, the film formation was finished.
　成膜後、多結晶ＳｉＣ膜から黒鉛基材を除去し、直径２１５ｍｍ、厚さ３ｍｍの多結晶ＳｉＣ成形体を得た。次いで、得られた多結晶ＳｉＣ成形体について、黒鉛基材と分離された面及び／又はその面と対向する面を研削加工により、平滑な面とした。更に、多結晶ＳｉＣ成形体の直径を所定の直径に整えるように加工を施した。その結果、直径２１０ｍｍ、厚さ２ｍｍの多結晶ＳｉＣ成形体を得た。これを、実施例１に係る多結晶ＳｉＣ成形体とした。 After film formation, the graphite base material was removed from the polycrystalline SiC film to obtain a polycrystalline SiC compact with a diameter of 215 mm and a thickness of 3 mm. Then, the obtained polycrystalline SiC molded body was ground to a smooth surface on the surface separated from the graphite substrate and/or the surface opposite to the surface. Further, the polycrystalline SiC molded body was processed so as to have a predetermined diameter. As a result, a polycrystalline SiC compact with a diameter of 210 mm and a thickness of 2 mm was obtained. This was used as a polycrystalline SiC compact according to Example 1.
（実施例２～６及び比較例１～６）
　実施例１と同様に、多結晶ＳｉＣ膜を成膜した。ここで、多結晶ＳｉＣ膜の成膜条件を、表１及び２に示される通りの条件に変更した。 (Examples 2-6 and Comparative Examples 1-6)
A polycrystalline SiC film was formed in the same manner as in Example 1. Here, the conditions for forming the polycrystalline SiC film were changed to the conditions shown in Tables 1 and 2.
（評価方法）
　実施例1～６及び比較例１～６で得られた多結晶ＳｉＣ成形体について、第１の組織の面積比率、平均結晶粒径、ＳｉＣ（１１１）面のＸ線回折ピーク強度の比率、空隙率、ＪＩＳ　Ｒ　１６０１における３点曲げ強度、ヤング率、および熱伝導率を求めた。各値の測定方法について、以下に説明する。 (Evaluation method)
Regarding the polycrystalline SiC compacts obtained in Examples 1 to 6 and Comparative Examples 1 to 6, the area ratio of the first structure, the average crystal grain size, the ratio of the X-ray diffraction peak intensity of the SiC (111) plane, the void modulus, three-point bending strength in JIS R 1601, Young's modulus, and thermal conductivity were determined. A method for measuring each value will be described below.
［第１の組織の面積分率］
　ＴＳＬソリューションズ社製　ＤｉｇｉＶｉｅｗにより、実施例1～６及び比較例１～６で得られた多結晶ＳｉＣ成形体の主面法線方向±１０°方向（以下ＮＤ方向という。）についてＥＢＳＤ方位マップを測定した。
　ＥＢＳＤ方位マップのうち、３Ｃ型結晶構造ＳｉＣの（１１１）面、（２００）面、（２２０）面又は（３１１）面が、ＮＤ方向に沿って配向している領域を、「第１の組織」として抽出した。抽出結果に基づき、測定領域１００μｍ×１００μｍにおける「第１の組織」の面積分率（％）を求めた。 [Area fraction of the first structure]
Using DigiView manufactured by TSL Solutions, EBSD orientation maps were measured in the ±10° direction (hereinafter referred to as the ND direction) of the main surface normal direction of the polycrystalline SiC molded bodies obtained in Examples 1 to 6 and Comparative Examples 1 to 6. bottom.
In the EBSD orientation map, the (111) plane, (200) plane, (220) plane or (311) plane of the 3C type crystal structure SiC is oriented along the ND direction. ” was extracted. Based on the extraction results, the area fraction (%) of the “first structure” in the measurement area of 100 μm×100 μm was obtained.
　ＥＢＳＤ方位マップの測定条件は、下記の通りとした。
前処理：　　機械研磨、カーボン蒸着
装置：　　　ＦＥ－ＳＥＭ　日立ハイテク製　ＳＵ－７０
　　　　　　ＥＢＳＤ　ＴＳＬソリューションズ社製　ＤｉｇｉＶｉｅｗ
測定条件：　電圧：　　　　　２０ｋＶ
　　　　　　径射角：　　　　７０°
　　　　　　測定領域：　　　１００μｍ×１００μｍ
　　　　　　測定間隔：　　　０．０３μｍ
　　　　　　評価対象結晶系：３C型ＳｉＣ（空間群　２１６） The measurement conditions for the EBSD orientation map were as follows.
Pretreatment: Mechanical polishing, carbon deposition equipment: FE-SEM SU-70 manufactured by Hitachi High-Tech
DigiView manufactured by EBSD TSL Solutions
Measurement conditions: Voltage: 20 kV
Radial angle: 70°
Measurement area: 100 μm×100 μm
Measurement interval: 0.03 μm
Evaluation target crystal system: 3C type SiC (space group 216)
［平均結晶粒径］
　上記で測定したＥＢＳＤ方位マップを用いて、全領域（１００μｍ×１００μｍ）内において、単一領域の面積にその単一領域の面積を観測領域の全面積で除した値を乗じた値を、全ての単一領域について求め、それらの合計値を算出した。 [Average grain size]
Using the EBSD orientation map measured above, in the entire area (100 μm × 100 μm), the value obtained by multiplying the area of the single region by the value obtained by dividing the area of the single region by the total area of the observation region was obtained for a single region of the , and their total value was calculated.
［ＳｉＣ（１１１）面のX線回折ピーク強度の比率］
　実施例1～６及び比較例１～６で得られた多結晶ＳｉＣ成形体の主面の中心について、２θ／θ法によるＸ線回折パターンを、島津製作所製　ＸＲＤ－６０００を用いて、以下条件にて測定した。
　Ｃｕターゲット
　電圧：４０．０ｋＶ
　電流：２０．０ｍＡ
　発散スリット：１．０００００ｄｅｇ．
　散乱スリット：１．０００００ｄｅｇ．
　受光スリット：０．３００００ｍｍ
　スキャンレンジ：２０．０００～８０．０００ｄｅｇ
　スキャンスピード：４．００００ｄｅｇ．／ｍｉｎ．
　サンプリングピッチ：０．０２００ｄｅｇ．
　プリセットタイム：０．３０ｓｅｃ． [Ratio of X-ray diffraction peak intensity of SiC (111) plane]
About the center of the main surface of the polycrystalline SiC molded bodies obtained in Examples 1 to 6 and Comparative Examples 1 to 6, X-ray diffraction patterns by the 2θ/θ method were measured using XRD-6000 manufactured by Shimadzu Corporation under the following conditions. Measured at
Cu target voltage: 40.0 kV
Current: 20.0mA
Divergence slit: 1.00000deg.
Scattering slit: 1.00000 deg.
Light receiving slit: 0.30000mm
Scan range: 20.000 to 80.000deg
Scan speed: 4.0000deg. /min.
Sampling pitch: 0.0200deg.
Preset time: 0.30 sec.
　得られたＸ線回折パターンにおいて、回折角２θが２０．０～８０．０ｄｅｇ．の範囲における回折ピーク強度の平均値を、バックグラウンドの補正値とし、回折角２θが３５．３～３６．０ｄｅｇ．の範囲における回折ピーク強度を、３Ｃ型結晶構造ＳｉＣの（１１１）面の回折ピーク強度として求めた。
　同様に、回折角２θが４１．１～４１．８ｄｅｇ．の範囲における回折ピーク強度を、ＳｉＣ（２００）面の回折ピーク強度として求めた。
　同様に、回折角２θが５９．７～６０．３ｄｅｇ．の範囲における回折ピーク強度を、ＳｉＣ（２２０）面の回折ピーク強度として求めた。
　同様に、回折角２θが７１．５～７２．３ｄｅｇ．の範囲における回折ピーク強度を、ＳｉＣ（３１１）面の回折ピーク強度として求めた。
　そして、ＳｉＣ（１１１）面、ＳｉＣ（２００）面、ＳｉＣ（２２０）面、およびＳｉＣ（３１１）面の回折ピーク強度の合計値を求めた。更に、合計値に対する、ＳｉＣ（１１１）面の回折ピーク強度の比率を、ＳｉＣ（１１１）面のＸ線回折ピーク強度の比率として求めた。 In the obtained X-ray diffraction pattern, the diffraction angle 2θ was 20.0 to 80.0 deg. is used as the background correction value, and the diffraction angle 2θ is 35.3 to 36.0 deg. was obtained as the diffraction peak intensity of the (111) plane of the 3C-type crystal structure SiC.
Similarly, when the diffraction angle 2θ is 41.1 to 41.8 deg. was obtained as the diffraction peak intensity of the SiC (200) plane.
Similarly, when the diffraction angle 2θ is 59.7 to 60.3 deg. was obtained as the diffraction peak intensity of the SiC (220) plane.
Similarly, when the diffraction angle 2θ is 71.5 to 72.3 deg. was obtained as the diffraction peak intensity of the SiC (311) plane.
Then, the sum of the diffraction peak intensities of the SiC (111) plane, the SiC (200) plane, the SiC (220) plane, and the SiC (311) plane was obtained. Furthermore, the ratio of the diffraction peak intensity of the SiC (111) plane to the total value was obtained as the ratio of the X-ray diffraction peak intensity of the SiC (111) plane.
［空隙率］
　実施例1～６及び比較例１～６で得られた多結晶ＳｉＣ成形体をその主面法線方向に沿って切断し、露出した多結晶ＳｉＣ成形体の断面について、ＳＥＭを用いて反射電子像及び二次電子像を取得した。観察視野を７００μｍ×１３００μｍと設定して、その観察視野内において、外接する円の直径が１μｍを超える空隙の数を計測し、空隙率（個／ｃｍ2）を算出した。 [Porosity]
The polycrystalline SiC molded bodies obtained in Examples 1 to 6 and Comparative Examples 1 to 6 were cut along the direction normal to the main surface, and the cross section of the exposed polycrystalline SiC molded body was observed using an SEM. Images and secondary electron images were acquired. An observation field of view was set to 700 μm×1300 μm, and the number of voids having a circumscribed circle diameter exceeding 1 μm was counted in the observation field of view to calculate the porosity (pieces/cm 2 ).
［３点曲げ強度及びヤング率］
　以下の装置及び条件により、ＪＩＳ　Ｒ　１６０１に基づいて、実施例1～６及び比較例１～６で得られた多結晶ＳｉＣ成形体の室温でのＪＩＳ　Ｒ　１６０１における３点曲げ強度及びヤング率を求めた。
　装置　　オートグラフ　ＳＨＩＭＡＤＺＵ　AG－Ｘ　リフレッシュ（ベースモデル：ＡＧ－１０ＴＢ）
　ロードセル　　　５ｔｆ又は５０ｋｇｆ
　試験モード　　　シングル
　試験種類　　　　３点曲げ
　速度　　　　　　０．５ｍｍ／ｍｉｎ．
　下部支点間距離　３６ｍｍ
　弾性率の算出範囲　試験力　０．１～０．５Ｋｇｆ
　測定試験片サイズ　１０×０．５×４０mm又は１０×２×４０mm [Three-point bending strength and Young's modulus]
Using the following apparatus and conditions, the three-point bending strength and Young's modulus in JIS R 1601 at room temperature of the polycrystalline SiC molded bodies obtained in Examples 1 to 6 and Comparative Examples 1 to 6 were measured based on JIS R 1601. asked.
Equipment Autograph SHIMADZU AG-X refresh (base model: AG-10TB)
Load cell 5tf or 50kgf
Test mode Single Test type 3-point bending Speed 0.5mm/min.
Lower fulcrum distance 36mm
Calculation range of elastic modulus Test force 0.1 to 0.5Kgf
Measurement specimen size 10 x 0.5 x 40 mm or 10 x 2 x 40 mm
［熱伝導率］
　以下の装置及び条件により、実施例1～６及び比較例１～６で得られた多結晶ＳｉＣ成形体の主面に対する法線方向の熱伝導率を求めた。
　装置：　　熱物性測定装置サーモウェーブアナライザＴＡ
　手法：　　周期加熱放射測温法
　環境温度：室温 [Thermal conductivity]
The thermal conductivity in the direction normal to the main surface of the polycrystalline SiC compacts obtained in Examples 1 to 6 and Comparative Examples 1 to 6 was determined using the following apparatus and conditions.
Apparatus: thermophysical property measuring device Thermo Wave Analyzer TA
Method: Periodic heating radiation thermometry Environmental temperature: Room temperature
（結果の考察）
　表１及び２に、結果を示す。実施例１～６に係る多結晶ＳｉＣ成形体は、平均結晶粒径が５μm以下であり、第１の組織の面積分率が、２２～４８％であり、ＳｉＣ（１１１）面のＸ線回折ピーク強度の比率が、８０％以上（すなわち、０．８以上）であった。実施例１～６は、比較例１～６に比べて、ＪＩＳ　Ｒ　１６０１における３点曲げ強度、ヤング率及び熱伝導率が優れていた。
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
 (Discussion of results)
Tables 1 and 2 show the results. The polycrystalline SiC molded bodies according to Examples 1 to 6 have an average crystal grain size of 5 μm or less, an area fraction of the first structure of 22 to 48%, and an X-ray diffraction of the SiC (111) plane The peak intensity ratio was 80% or greater (ie, 0.8 or greater). Examples 1-6 were superior to Comparative Examples 1-6 in 3-point bending strength, Young's modulus and thermal conductivity according to JIS R 1601.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
　１　多結晶ＳｉＣ成形体
　２　主面
　３　第１の組織
　４　第２の組織
　５　多結晶ＳｉＣ成形体の製造システム
　６　ＣＶＤ反応炉
　７　混合部
　８　キャリアガス容器
　９　原料ガス容器
　１０　窒素含有ガス容器
　１１　流量計
　１２　ガス導入ノズル
　１３　支持基材 REFERENCE SIGNS LIST 1 polycrystalline SiC compact 2 main surface 3 first structure 4 second structure 5 polycrystalline SiC compact manufacturing system 6 CVD reactor 7 mixing section 8 carrier gas container 9 source gas container 10 nitrogen-containing gas container 11 flow rate Total 12 Gas introduction nozzle 13 Support base material

Claims (4)

  1. 　第１の組織と第２の組織とからなる多結晶ＳｉＣ成形体であって、
    　前記多結晶ＳｉＣ成形体は、板状であって、略平面の主面を有し、
    　前記第１の組織は、３Ｃ型結晶構造を有する多結晶ＳｉＣであって、
    　前記第２の組織は、前記第１の組織と異なる組織であり、
    　前記第１の組織は、前記多結晶ＳｉＣ成形体の前記主面の略法線方向に沿って、（１１１）面、（２００）面、（２２０）面又は（３１１）面が配向した組織であり、
    　前記主面における前記第１の組織の面積分率が０％超５０％未満であり、
    　平均結晶粒径が５μｍ以下であり、
    　前記主面におけるＸ線回折パターンにおいて、ＳｉＣ（１１１）面、ＳｉＣ（２００）面、ＳｉＣ（２２０）面、およびＳｉＣ（３１１）面のＸ線回折ピーク強度の合計に対する、ＳｉＣ（１１１）面のＸ線回折ピーク強度の比率が、０．８以上である、
    多結晶ＳｉＣ成形体。     A polycrystalline SiC compact comprising a first structure and a second structure,
    The polycrystalline SiC molded body is plate-shaped and has a substantially flat main surface,
    The first structure is polycrystalline SiC having a 3C type crystal structure,
    The second tissue is a tissue different from the first tissue,
    The first structure is a structure in which the (111) plane, the (200) plane, the (220) plane, or the (311) plane is oriented substantially along the normal direction of the main surface of the polycrystalline SiC compact. can be,
    The area fraction of the first structure in the main surface is more than 0% and less than 50%,
    The average crystal grain size is 5 μm or less,
    In the X-ray diffraction pattern on the main surface, the SiC (111) surface with respect to the total X-ray diffraction peak intensity of the SiC (111) surface, the SiC (200) surface, the SiC (220) surface, and the SiC (311) surface The ratio of X-ray diffraction peak intensities is 0.8 or more,
    Polycrystalline SiC compact.
  2. 　断面が、外接する円の直径が１μｍ超である空隙を、１ｃｍ2当たりに０個以上４０個未満含む、請求項１に記載の多結晶ＳｉＣ成形体。 2. The polycrystalline SiC compact according to claim 1, wherein the cross section includes 0 or more and less than 40 voids per 1 cm <2 > having a circumscribed circle diameter of more than 1 [mu]m.
  3. 　前記主面の法線方向における熱伝導率が９０～１３０Ｗ／ｍ・Ｋである、請求項１又は２に記載の多結晶ＳｉＣ成形体。 The polycrystalline SiC compact according to claim 1 or 2, wherein the thermal conductivity in the normal direction of the main surface is 90 to 130 W/m·K.
  4. 　ＪＩＳ　Ｒ　１６０１における３点曲げ強度が５６０ＭＰａ以上、且つヤング率が２５０ＧＰａ以上である、請求項１～３のいずれか１項に記載の多結晶ＳｉＣ成形体。 The polycrystalline SiC molded body according to any one of claims 1 to 3, which has a three-point bending strength of 560 MPa or more and a Young's modulus of 250 GPa or more according to JIS R 1601.
PCT/JP2022/040454 2021-12-24 2022-10-28 POLYCRYSTALLINE SiC MOLDED BODY WO2023119874A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1179846A (en) * 1997-09-01 1999-03-23 Tokai Carbon Co Ltd Silicon carbide formed product
JP2016092122A (en) * 2014-10-31 2016-05-23 三井造船株式会社 Silicon carbide substrate
JP2021046336A (en) * 2019-09-18 2021-03-25 住友金属鉱山株式会社 Method for processing surface of graphite support substrate, method for depositing silicon carbide polycrystalline film and method for manufacturing silicon carbide polycrystalline substrate

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1179846A (en) * 1997-09-01 1999-03-23 Tokai Carbon Co Ltd Silicon carbide formed product
JP2016092122A (en) * 2014-10-31 2016-05-23 三井造船株式会社 Silicon carbide substrate
JP2021046336A (en) * 2019-09-18 2021-03-25 住友金属鉱山株式会社 Method for processing surface of graphite support substrate, method for depositing silicon carbide polycrystalline film and method for manufacturing silicon carbide polycrystalline substrate

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