WO2025249355A1 - TRANCHE DE MONOCRISTAL DE SiC, LINGOT DE MONOCRISTAL DE SiC, PROCÉDÉ DE PRODUCTION DE TRANCHE DE MONOCRISTAL DE SiC, PROCÉDÉ DE PRODUCTION DE LINGOT DE MONOCRISTAL DE SiC, DISPOSITIF DE PRODUCTION DE LINGOT DE MONOCRISTAL DE SiC ET PROCÉDÉ DE FORMATION DE FILM FORMÉ PAR CROISSANCE ÉPITAXIALE DE SiC - Google Patents

TRANCHE DE MONOCRISTAL DE SiC, LINGOT DE MONOCRISTAL DE SiC, PROCÉDÉ DE PRODUCTION DE TRANCHE DE MONOCRISTAL DE SiC, PROCÉDÉ DE PRODUCTION DE LINGOT DE MONOCRISTAL DE SiC, DISPOSITIF DE PRODUCTION DE LINGOT DE MONOCRISTAL DE SiC ET PROCÉDÉ DE FORMATION DE FILM FORMÉ PAR CROISSANCE ÉPITAXIALE DE SiC

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Publication number
WO2025249355A1
WO2025249355A1 PCT/JP2025/018874 JP2025018874W WO2025249355A1 WO 2025249355 A1 WO2025249355 A1 WO 2025249355A1 JP 2025018874 W JP2025018874 W JP 2025018874W WO 2025249355 A1 WO2025249355 A1 WO 2025249355A1
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WIPO (PCT)
Prior art keywords
single crystal
sic single
sic
space
diameter
Prior art date
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Pending
Application number
PCT/JP2025/018874
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English (en)
Japanese (ja)
Inventor
和人 熊谷
準也 松村
智典 梅崎
裕 松田
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Central Glass Co Ltd
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Central Glass Co Ltd
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Publication of WO2025249355A1 publication Critical patent/WO2025249355A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • 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
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • 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
    • C30B19/00—Liquid-phase epitaxial-layer growth
    • C30B19/10—Controlling or regulating
    • 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

  • SiC single crystal wafers SiC single crystal ingots, SiC single crystal wafer manufacturing methods, SiC single crystal ingot manufacturing methods, SiC single crystal ingot manufacturing equipment, and SiC epitaxial growth film deposition methods.
  • silicon with metal added is generally melted in a carbon crucible, and then a pulling shaft with a seed crystal attached is brought into contact with the melt to crystallize it.
  • the solvent may be incorporated directly into the crystal (solvent inclusion). These solvent inclusions are in a molten state in the high-temperature environment during growth, but solidify as cooling progresses after growth is completed. This generates strong stress, which can cause problems with the crystallinity of the growing crystal.
  • Patent Document 1 discloses a technology for improving solvent inclusions in SiC single crystal growth using a solution method by controlling the growth interface to be concave and directing the solvent flow near the growth interface outward from the center.
  • Patent Document 2 discloses a manufacturing device that stores SiC solution in a crucible having a lower storage chamber and an upper storage chamber with different diameters.
  • the diameter ratio of the lower storage chamber to the upper storage chamber is adjusted to optimize the flow rate of the upward flow. Specifically, the ratio (diameter of the lower storage chamber) / (diameter of the upper storage chamber) is adjusted to 0.25 to 0.65.
  • Patent Document 2 The maximum diameter of the SiC single crystals for which the technology in Patent Document 1 has been confirmed to improve solvent inclusions is a relatively small 44.6 mm. Patent Document 2 does not mention solvent inclusions.
  • One example of the objective of this disclosure is to improve solvent inclusions in SiC single crystals with larger diameters than those of conventional techniques.
  • a SiC single crystal wafer in which the area ratio of solvent inclusion regions to the surface, as observed in an image of the surface, is 5% or less.
  • a growth step of contacting a SiC seed crystal with a raw material solution containing Si and C to form a growth layer of a SiC single crystal on a surface of the SiC seed crystal provides a method for producing a SiC single crystal ingot, in which the standard deviation of the total thickness of the SiC seed crystal and the growth layer in an as-grown state obtained in the growth step, measured at 2 mm intervals from the center toward the periphery, is 300 ⁇ m or less.
  • a growth step of contacting a SiC seed crystal with a raw material solution containing Si and C to form a growth layer of a SiC single crystal on a surface of the SiC seed crystal In the growing step, a crucible having a solution containing space surrounded by a bottom, a sidewall, and an opening facing the bottom, the solution containing space containing the raw material solution; a chamber containing the crucible; a pulling shaft to which the SiC seed crystal having a diameter of 4 inches or more is attached; a heater for heating the raw material solution contained in the crucible; and
  • the solution-containing space of the crucible is a first space and a second space having different diameters in a cross section perpendicular to a height direction from the bottom portion toward the opening portion; the first space and the second space are arranged side by side in the height direction and connected to each other,
  • a method for manufacturing a SiC single crystal ingot is provided, in which the growth layer is produced using a manufacturing device in which the diameter
  • producing a SiC single crystal ingot by the method for producing a SiC single crystal ingot; cutting a SiC single crystal wafer from the SiC single crystal ingot; A method for producing a SiC single crystal wafer having the following structure is provided.
  • a crucible having a solution containing space surrounded by a bottom, a sidewall, and an opening facing the bottom, the solution containing space containing a raw material solution containing Si and C; a chamber containing the crucible; a pulling shaft to which a SiC seed crystal having a diameter of 4 inches or more is attached; a heater for heating the raw material solution contained in the crucible; and
  • the solution-containing space of the crucible is a first space and a second space having different diameters in a cross section perpendicular to a height direction from the bottom portion toward the opening portion; the first space and the second space are arranged side by side in the height direction and connected to each other,
  • the present invention provides an apparatus for manufacturing a SiC single crystal ingot, wherein the diameter of the cross section of the first space located on the bottom side is smaller than the diameter of the cross section of the second space located on the opening side.
  • One aspect of the present disclosure provides a technique for improving solvent inclusions in SiC single crystals with larger diameters than conventional techniques.
  • FIG. 1 is a diagram for explaining the characteristics of a SiC single crystal ingot.
  • FIG. 2 is a flowchart showing an example of a method for manufacturing a SiC single crystal ingot.
  • FIG. 3 is a diagram showing an outline of an example of a crystal growth apparatus.
  • FIG. 4 is a flowchart showing an example of a method for manufacturing a SiC single crystal wafer.
  • FIG. 5 is a diagram showing an outline of another example of a crystal growth apparatus.
  • FIG. 6 is a diagram for explaining the effects achieved by using the crystal growth apparatus of FIG.
  • FIG. 7 is another diagram for explaining the characteristics of the SiC single crystal ingot.
  • SiC single crystal wafer of this embodiment is manufactured by a "solution process.” Although the SiC single crystal wafer of this embodiment is manufactured by a solution process, it has both of the following wafer features 1 and 2.
  • “Wafer feature 1” Diameter of 4 inches or more, preferably 6 inches or more or 8 inches or more.
  • the solvent inclusion region is a portion of the SiC single crystal wafer in the image where solvent inclusions are present.
  • the SiC single crystal wafer of this embodiment despite being manufactured by a solution method, has a relatively large diameter and exhibits sufficiently reduced solvent inclusions.
  • the SiC single crystal wafer of this embodiment may contain solvent inclusions. For this reason, the SiC single crystal wafer of this embodiment may further have the following characteristics.
  • Wafer Feature 3 The area ratio of solvent inclusions observed in surface images to the surface is 0.01% or greater.
  • the SiC single crystal wafer of this embodiment may further have the following wafer feature 4.
  • the SiC single crystal wafer of this embodiment may further have the following wafer feature 5.
  • the TSD (threading screw dislocation) density or BPD (basal plane dislocation) density in the center of the surface is 100/ cm2 or less, preferably 50/ cm2 or less, 20/cm2 or less , or 10/cm2 or less .
  • both the TSD (threading screw dislocation) density and the BPD (basal plane dislocation) density may satisfy the above numerical ranges.
  • the SiC single crystal wafer of this embodiment is manufactured by slicing it from a grown SiC single crystal.
  • the "area ratio” shown in wafer features 2 and 3 is a value measured as follows.
  • the "area ratio” shown in ingot features 2 and 3, described below, is also a value measured in the same way.
  • the area measurement function of a digital microscope can be used to calculate the area ratio.
  • An image of the entire crystal surface is obtained, the brightness of the entire crystal surface is expressed as 0 to 255, and areas below 100 are considered to be solvent inclusions and color-coded.
  • the area of the color-coded areas is then divided by the area of the entire crystal surface to determine the area ratio of solvent inclusions.
  • the SiC single crystal wafer of this embodiment is preferably a crystal polytype represented by 4H-SiC and 6H-SiC.
  • the SiC single crystal wafer of this embodiment may be an on-substrate whose surface is the (0001) or (000-1) plane, or an off-substrate whose surface is cut at an angle of 0.5 to 5 degrees relative to the (0001) or (000-1) plane.
  • the SiC single crystal wafer of this embodiment can have at least one of the following wafer features 6 and 7.
  • the SiC single crystal wafer of this embodiment may or may not have at least one of wafer features 1 to 5.
  • the surface Cr concentration per area is 1 ⁇ 10 15 atoms/cm 2 or less.
  • the surface Cr concentration per area may be 1 ⁇ 10 13 atoms/cm 2 or less, 1 ⁇ 10 11 atoms/cm 2 or less, 5 ⁇ 10 10 atoms/cm 2 or less, or 1 ⁇ 10 10 atoms/cm 2 or less.
  • the lower limit is not particularly limited, but may be 0 atoms/cm 2 or more, or 1 ⁇ 10 8 atoms/cm 2 or more.
  • the Cr concentration per surface area is a value measured on the surface of a SiC single crystal wafer using a total reflection X-ray fluorescence analyzer (TXRF).
  • TXRF total reflection X-ray fluorescence analyzer
  • the Cr concentration per surface area was measured using a total reflection X-ray fluorescence analyzer (Rigaku Corporation TXRF-3800e).
  • "Wafer Feature 7" Cr concentration per volume is 1 ⁇ 10 16 atoms/cm 3 or more.
  • the Cr concentration per volume may be 1 ⁇ 10 17 atoms/cm 3 or more, or 5 ⁇ 10 17 atoms/cm 3 or more.
  • the upper limit is not particularly limited, but may be 1 ⁇ 10 20 atoms/cm 3 or less, or 1 ⁇ 10 19 atoms/cm 3 or less.
  • the Cr concentration per volume is a value measured at one point in the center of the SiC single crystal wafer using secondary ion mass spectrometry (SIMS).
  • SIMS secondary ion mass spectrometry
  • the Cr concentration per volume was measured in dynamic SIMS mode using a secondary ion mass spectrometer (IMS-7F, CAMECA).
  • SiC single crystal ingot of this embodiment is produced by the "solution method.” Although the SiC single crystal ingot of this embodiment is produced by the solution method, it has both of the following ingot characteristics 1 and 2.
  • Ingot feature 1 Diameter is 4 inches or more, preferably 6 inches or more or 8 inches or more.
  • Ingot feature 2 The area ratio of the solvent inclusion region observed in an image of the surface (growth surface) to the surface is 5% or less, preferably 1% or less.
  • Ingot feature 1 means that among the cross sections perpendicular to the pulling direction (long axis direction), there is a cross section with a diameter of 4 inches or more, preferably 6 inches or more or 8 inches or more. It is sufficient that any of the cross sections perpendicular to the pulling direction (long axis direction) meet the requirement of "a diameter of 4 inches or more, preferably 6 inches or more or 8 inches or more," and it is not necessary for all cross sections to meet the requirement of "a diameter of 4 inches or more, preferably 6 inches or more or 8 inches or more.”
  • the SiC single crystal ingot of this embodiment although produced by the solution method, has a relatively large diameter and exhibits sufficiently reduced solvent inclusions.
  • the SiC single crystal ingot of this embodiment is produced by a solution method and may contain solvent inclusions. For this reason, the SiC single crystal ingot of this embodiment may further have the following ingot feature 3.
  • the SiC single crystal ingot of this embodiment can further have the following ingot feature 4.
  • the ingot thickness be 10 mm or more, 5 cm or more, 10 cm or more, or 20 cm or more.
  • the SiC single crystal ingot of this embodiment has a sufficient thickness of 1 mm or more, the solvent inclusion area on the growth surface is sufficiently small, as shown in ingot feature 2.
  • the SiC single crystal ingot of this embodiment can further have the following ingot feature 5.
  • Figure 1 shows a stack of a seed crystal 10 and a growth layer 20.
  • the growth layer 20 is produced by bringing a raw material solution into contact with the planar surface G of the seed crystal 10 and growing a SiC single crystal.
  • the as-grown state is the state obtained by crystal growth, and the growth surface F has not been subjected to any processing such as polishing.
  • the SiC single crystal ingot (growth layer 20) having ingot feature 5 has a standard deviation of 300 ⁇ m or less in thicknesses t1 to tn measured at 2 mm intervals from the center C of the surface (growth plane F) toward the outer periphery P in the as-grown state.
  • the SiC single crystal ingot of this embodiment can further have the following ingot feature 6.
  • Figure 7 shows a stack of a seed crystal 10 and a growth layer 20 (hereinafter sometimes referred to as the "grown crystal").
  • the “total thickness of the seed crystal 10 and the growth layer 20 in the as-grown state” can be said to be the thickness of the grown crystal in the as-grown state.
  • a SiC single crystal ingot having ingot feature 6 has a standard deviation of 300 ⁇ m or less in thicknesses t'1 to t'n of the grown crystal measured at 2 mm intervals from the center C of the surface (growth surface) toward the outer periphery P.
  • the SiC single crystal ingot of this embodiment may further have the following ingot feature 7.
  • “Flat” is defined as the standard deviation of the thickness of the grown crystal, as defined in ingot characteristic 6, being 50 ⁇ m or less. Note that if the seed crystal 10 is removed, "flat” is defined as the standard deviation of the thickness of the growth layer 20, as defined in ingot characteristic 5, being 50 ⁇ m or less.
  • cave is defined as a state in which the thickness t'1 of the grown crystal at the center C of the surface (growth surface) is smaller than the thickness t'n of the grown crystal at the periphery P.
  • the term “concave” is defined as a state in which the thickness t1 of the grown layer 20 at the center C of the surface (growth surface) is smaller than the thickness tn of the grown layer 20 at the periphery P.
  • the concave SiC single crystal ingot of this embodiment can further have at least one of the above-mentioned ingot features 5 and 6.
  • An SiC single crystal ingot that has at least one of ingot features 5 and 6 and has a concave surface (growth surface) can be said to have a gently concave surface (growth surface) that is closer to a plane (flat).
  • the SiC single crystal ingot of this embodiment having ingot feature 7 satisfies the following conditions. (Total thickness of the seed crystal and the outer periphery of the as-grown growth layer) ⁇ (Total thickness of the seed crystal and the center of the as-grown growth layer)
  • the SiC single crystal ingot of this embodiment having the ingot feature 7 satisfies the following conditions: (thickness of the outer part of the as-grown growth layer) ⁇ (thickness of the center part of the as-grown growth layer)
  • the SiC single crystal ingot of this embodiment may further have the following ingot feature 8.
  • TSD thread screw dislocation
  • BPD basic plane dislocation
  • both the TSD (threading screw dislocation) density and the BPD (basal plane dislocation) density may satisfy the above numerical ranges.
  • the SiC single crystal ingot of this embodiment can use crystal polytypes such as 4H-SiC and 6H-SiC.
  • the SiC single crystal ingot of this embodiment may have a (0001) or (000-1) surface, or may have a surface cut at an angle of 0.5 to 5 degrees relative to the (0001) or (000-1) surface.
  • solvent inclusions can be reduced by growing the growth layer 20 while maintaining the growth surface F in a state closer to a plane (closer to flatness). It is difficult to maintain a perfectly flat growth surface F during the growth of the growth layer 20, and some areas may become tilted, recessed, or convex. By reducing the extent of this, solvent inclusions can be reduced. Furthermore, while it is preferable to make the growth surface F of the growth layer 20 as flat as possible, if unevenness is formed, solvent inclusions can be reduced by making it concave.
  • the standard deviation of the thicknesses t'1 to t'n of the grown crystal measured at 2 mm intervals from the center C of the surface (growth surface F) toward the periphery P in the as-grown state is sufficiently reduced to 300 ⁇ m or less. Furthermore, in the SiC single crystal ingot of this embodiment, the standard deviation of the thicknesses t1 to tn of the grown layer measured at 2 mm intervals from the center C of the surface (growth surface F) toward the periphery P in the as-grown state is sufficiently reduced to 300 ⁇ m or less.
  • the SiC single crystal ingot of this embodiment may have a seed crystal 10 and a growth layer 20 in contact with the seed crystal 10, as shown in FIG. 1.
  • the SiC single crystal ingot of this embodiment may be one in which the seed crystal 10 has been removed from a layered structure (grown crystal) of the seed crystal 10 and growth layer 20 as shown in FIG. 1.
  • the SiC single crystal ingot of this embodiment may have at least one of the following ingot features 9 and 10.
  • the SiC single crystal ingot of this embodiment may or may not have at least one of ingot features 1 to 8.
  • the Cr concentration per area of the surface of the growth layer 20 is 1 ⁇ 10 15 atoms/cm 2 or less.
  • the Cr concentration per area of the surface may be 1 ⁇ 10 13 atoms/cm 2 or less, 1 ⁇ 10 11 atoms/cm 2 or less, 5 ⁇ 10 10 atoms/cm 2 or less, or 1 ⁇ 10 10 atoms/cm 2 or less.
  • the lower limit is not particularly limited, but may be 0 atoms/cm 2 or more, or 1 ⁇ 10 8 atoms/cm 2 or more.
  • the Cr concentration per volume of the growth layer 20 is 1 ⁇ 10 16 atoms/cm 3 or more.
  • the Cr concentration per volume may be 1 ⁇ 10 17 atoms/cm 3 or more, or 5 ⁇ 10 17 atoms/cm 3 or more.
  • the upper limit is not particularly limited, but may be 1 ⁇ 10 20 atoms/cm 3 or less, or 1 ⁇ 10 19 atoms/cm 3 or less.
  • a SiC single crystal wafer cut from a SiC single crystal ingot has wafer feature 7 and therefore ingot feature 10.
  • SiC single crystal wafers sliced from such SiC single crystal ingots of this embodiment have wafer characteristics 1 and 2 described above, and may also have wafer characteristics 3 to 7 described above.
  • the method for manufacturing the SiC single crystal ingot according to this embodiment includes a growing step S10.
  • a growth layer of a SiC single crystal is produced by a solution method. That is, in the growth step S10, a SiC seed crystal is brought into contact with a raw material solution containing Si and C, and a growth layer of a SiC single crystal is produced on the surface of the seed crystal.
  • the front and back surfaces of the seed crystal are flat.
  • the front surface of the seed crystal is the surface that contacts the growth layer.
  • the back surface of the seed crystal is the surface opposite to the surface that contacts the growth layer.
  • the surface of the seed crystal that contacts the raw material solution (the surface that contacts the growth layer) is a carbon surface ((000-1) plane), and it is preferable that the error from the (000-1) plane is ⁇ 0.1° or less.
  • the total thickness variation (TTV) of the seed crystal is preferably 10 ⁇ m or less.
  • the micropipe density is preferably 0.1/ cm2 or less.
  • a growth layer with a thickness of 1 mm or more can be produced.
  • the TTV is a value obtained by subtracting the highest point from the lowest point on the back surface of the wafer when the back surface of the wafer serving as a seed crystal is entirely attached to a flat chuck surface, and means the thickness variation based on the back surface of the wafer.
  • the growth layer is grown while maintaining the growth surface (the surface in contact with the raw material solution) of the growth layer in a more planar (flat) state.
  • the growth layer is grown so that the standard deviation of the thickness of the grown crystal measured at 2 mm intervals from the center of the surface (growth surface) toward the periphery is 300 ⁇ m or less.
  • the growth layer is grown so that the standard deviation of the thickness of the growth layer measured at 2 mm intervals from the center of the surface (growth surface) toward the periphery is 300 ⁇ m or less.
  • the growth layer may be grown to satisfy both of these conditions.
  • the growth step S10 employs one of the following growth methods 1 to 3 to achieve the growth of the characteristic growth layer described above.
  • Growth method 1 uses a seed crystal with a flat surface and increases the uniformity of the temperature distribution at the interface between the raw material solution and the growth layer (or the seed crystal without the growth layer), thereby achieving "growing the growth layer while maintaining the growth surface of the growth layer in a state closer to a plane (closer to flattening)."
  • the temperature of the raw material solution at the interface between the raw material solution and the seed crystal or growth layer where the temperature of the point facing the center of the seed crystal or growth layer is defined as a first temperature and the temperature of the point facing the periphery of the seed crystal or growth layer is defined as a second temperature, is set so that the absolute value of the "temperature difference between the first temperature and the second temperature" divided by the "distance between the center and the periphery" is 0.1 K/cm or less.
  • the above-described uniformity in temperature distribution can be achieved by adjusting the heater placement position, number of heaters, heater shape, etc. While it is difficult to confirm whether the above-described temperature distribution conditions are met while the growth layer is being grown, it is possible to confirm that the above-described temperature distribution conditions are met using the thermal fluid simulation described below.
  • the inventors have confirmed that when growth process S10 is performed with a heater configuration that satisfies the above-described temperature distribution conditions using the thermal fluid simulation described below, a SiC single crystal ingot having the above-described ingot characteristics can be produced. Note that as long as the above-described temperature distribution conditions are met in the thermal fluid simulation described below, there are no restrictions on the heater configuration (heater placement position, number of heaters, heater shape, etc.).
  • FIG 3 shows an overview of a crystal growth apparatus 1 that can be used in the growth step S10.
  • the crystal growth apparatus 1 has a crucible 3, a pulling shaft 7, and a heater 4 (a side heater 4a and a bottom heater 4b in Figure 3).
  • a SiC single crystal is produced by growing a crystal while contacting a SiC seed crystal 9 from above with a raw material solution 5 containing Si and C.
  • the figure shows a typical heater 4 configuration.
  • the heater 4 configuration is determined to satisfy the temperature distribution conditions described above through simulations described below.
  • the crystal growth apparatus 1 shown in Figure 3 has a raw material solution 5 containing Si and C inside a crucible 3, and a pulling shaft 7 that can rotate a seed crystal 9 attached to its tip, with its long axis serving as the rotation axis.
  • the centers of the crucible 3 and the pulling shaft 7 do not necessarily have to coincide, but it is preferable that they do, and it is more preferable that the center of the crucible 3, the rotation axis of the crucible 3, the center of the pulling shaft 7, and the rotation axis of the pulling shaft 7 all coincide.
  • the crucible 3 is preferably a graphite crucible made of graphite, which can supply carbon to the raw material solution 5.
  • crucibles other than graphite crucibles can be used as long as they can add hydrocarbon gas or a solid carbon source.
  • the rotation speed of the crucible 3 is preferably 5 to 50 rpm, and more preferably 20 to 40 rpm. Keeping the rotation speed within the above range enables efficient crystal growth without placing excessive strain on the equipment.
  • the crucible 3 may also be rotated while periodically reversing its direction of rotation between forward and reverse.
  • the crucible 3 is housed in a chamber (not shown).
  • the raw material solution 5 is heated by a heater 4 installed around the crucible 3, and is kept in a molten state.
  • the heater 4 may be an induction heater or a resistance heater.
  • the temperature inside the crucible 3 is preferably 1700 to 2100°C.
  • the temperature inside the crucible 3 is measured at or near the surface of the raw material solution 5, or inside the crucible 3, using a non-contact thermometer (CHINO, IR-CZH7 model).
  • the silicon source for the raw material solution can be metal silicon, silicon alloys, silicon compounds, etc.
  • the carbon source for the raw material solution can be solid carbon sources such as graphite, glassy carbon, and silicon carbide, or hydrocarbon gases such as methane, ethane, propane, and acetylene.
  • the source solution 5 is not particularly limited as long as it contains Si and C and is suitable for growing SiC crystals. However, it is preferable to use a solution in which C is dissolved in a Si solvent to which an additive element has been added.
  • the silicon alloy or silicon compound used as the silicon source for the source solution can be an alloy or compound of Si and at least one additive element selected from Ti, Cr, Sc, Ni, Al, Co, Mn, Mg, Ge, As, P, N, O, Dy, Y, Nb, Nd, and Fe.
  • a Si-Cr alloy containing 20 to 60 mol% Cr is preferred as the solvent due to its high carbon solubility, low vapor pressure, and chemical stability.
  • an inert gas such as a rare gas inside the crystal growth apparatus 1 to create an inert atmosphere.
  • an inert gas such as a rare gas
  • a gas that serves as a source of conductive impurities may be added to create a mixed gas atmosphere.
  • the pulling shaft 7 adjusts the position of the seed crystal 9 to grow a SiC single crystal on the surface of the seed crystal 9.
  • the diameter of the SiC single crystal may be approximately the same as that of the seed crystal 9, or the crystal may be grown so that its diameter is larger than that of the seed crystal 9.
  • the angle by which the diameter of the growing crystal is expanded is preferably 35 to 90 degrees, more preferably 60 to 90 degrees, and even more preferably 78 to 90 degrees.
  • the diameter of the growing crystal can be expanded to be larger than that of the seed crystal 9. Specifically, by lowering the solution temperature around the seed crystal and increasing the carbon supersaturation, the growth rate toward the side of the seed crystal increases, thereby expanding the crystal diameter.
  • a substrate holder that holds the seed crystal 9 is provided at the tip of the pulling shaft 7.
  • the substrate holder has a diameter of 4 inches or more, preferably 6 inches or more or 8 inches or more.
  • Such a large-diameter substrate holder can hold a large-diameter seed crystal 9.
  • the substrate holder can hold a seed crystal 9 with a diameter of 4 inches or more, preferably 6 inches or more or 8 inches or more.
  • a silicon carbide seed crystal 9 may be brought into contact with the raw material solution 5 whose concentration is not saturated, a melt-back process may be performed to dissolve a portion of the seed crystal 9, and then a SiC single crystal may be grown on the seed crystal 9.
  • the seed crystal 9 dissolves because the carbon concentration of the raw material solution 5 is unsaturated.
  • the unevenness of the surface of the seed crystal 9 disappears, and the underside of the seed crystal 9 becomes smooth.
  • the time for which the seed crystal 9 is immersed is adjusted, taking into account the dissolution rate, so that only a portion of the seed crystal 9 dissolves.
  • the raw material solution 5 is made supersaturated near the seed crystal 9, allowing a silicon carbide single crystal to grow on the seed crystal 9.
  • the method for performing the melt-back process is not particularly limited, if crucible 3 is made of graphite and carbon is supplied from crucible 3 to raw material solution 5, one possible method is to contact a seed crystal with raw material solution 5 at temperature T1 during the temperature rise. Because carbon dissolves slowly from crucible 3 and the carbon concentration of the raw material solution remains unsaturated during the temperature rise, when the seed crystal is contacted, carbon dissolves from crucible 3 and SiC dissolves from the seed crystal at the same time. By subsequently raising the temperature from T1 to T2 and maintaining it for a certain period of time to stabilize, carbon dissolves sufficiently from crucible 3, saturating the carbon concentration in the raw material solution, and allowing silicon carbide single crystals to grow on the seed crystal at temperature T2.
  • temperature T1 during the melt-back process of raw material solution 5 be 1420°C or higher and 2100°C or lower, and 1500°C or higher and 2000°C or lower. Furthermore, it is preferable that the temperature T2 during the crystal growth process is higher than T1, and T2 - T1 may be 5°C or higher, 50°C or higher, 100°C or higher, or 200°C or lower.
  • the amount of carbon source can be reduced during charging, the melt-back process can be performed while the raw material solution 5 is undersaturated, and then the carbon source can be supplied to the raw material solution 5 to increase the carbon concentration and perform the crystal growth process.
  • the underside of the seed crystal 9 is smoothed, resulting in good morphology in the subsequent crystal growth process.
  • Seed crystal 9 can be a crystal polytype such as 4H-SiC or 6H-SiC. Seed crystal 9 may be an on-substrate whose surface is a (000-1) plane, or an off-substrate whose surface is cut at an angle of 0.5 to 5 degrees relative to the (000-1) plane. The angle between the surface of seed crystal 9 and the (000-1) plane is called the off-angle.
  • the step flow direction is the direction in which the steps progress. For example, if the off-angle is formed toward the [11-20] direction, the step flow direction is the [11-20] direction. Regarding the off-angle, reference may be made to Figure 20 in WO 2014/034080, a patent document.
  • the thickness of seed crystal 9 is not particularly limited, but is typically 0.1 mm or greater.
  • At least the raw material solution 5 that comes into contact with the crystal growth surface of the seed crystal 9 must be in a supersaturated state.
  • Possible methods for achieving a supersaturated state of the solute C include the cooling method, in which the seed crystal substrate is immersed in a saturated SiC solution and then cooled to achieve a supersaturated state, and the temperature difference method, in which the seed crystal substrate is immersed in a SiC solution with a temperature gradient and SiC crystals are crystallized in the low-temperature portion.
  • the entire raw material solution 5 becomes supersaturated, so crystal growth can also be achieved by rotating the pulling shaft 7 while the seed crystal 9 is immersed in the raw material solution 5.
  • the seed crystal 9 may remain fixed, but is preferably rotated in a plane parallel to the surface of the raw material solution 5.
  • the rotation speed is preferably 20 to 300 rpm, and more preferably 20 to 150 rpm.
  • the seed crystal 9 rotates in a cycle of alternating forward and reverse rotation, with the cycle being approximately 30 seconds to 5 minutes. By periodically switching the direction of rotation, it is possible to control the flow of the raw material solution on the growth surface of the seed crystal during crystal growth.
  • the seed crystal 9, which is an off-substrate, can be cut out so that it has a specified off-angle with respect to the (000-1) plane. It is particularly preferable that the off-angle be in the range of 0.5 to 5 degrees from the [0001] direction to the [11-20] direction.
  • the seed crystal 9 is attached to the pulling shaft 7 so that the off-angled plane serves as the crystal growth surface and comes into contact with the raw material solution 5.
  • Growth method 2 uses a unique SiC single crystal ingot manufacturing apparatus (crystal growth apparatus) to achieve “growing a growth layer while maintaining the growth surface of the growth layer in a state closer to a plane (closer to flatness)."
  • Figure 5 shows a schematic diagram of an example of a crystal growth apparatus 1 used in growth method 2.
  • the illustrated crystal growth apparatus 1 differs from the crystal growth apparatus 1 described using Figure 3 in the configuration of the crucible 3.
  • the crystal growth apparatus 1 used in growth method 2 can have the same configuration as the crystal growth apparatus 1 described using Figure 3, except for the configuration of the crucible 3.
  • widely known technology can be used for the configuration other than the crystal growth apparatus 1 in growth method 2.
  • An example is as described for growth method 1.
  • the configuration of the crucible 3 will be described in detail below.
  • the crucible 3 has a solution containing space 3-4 surrounded by a bottom 3-1, a sidewall 3-2, and an opening 3-3.
  • the opening 3-3 faces the bottom 3-1.
  • a raw material solution 5 is contained in the solution containing space 3-4.
  • the opening 3-3 is open and not partitioned.
  • the pulling shaft 7 inserts a seed crystal 9 into the crucible 3 through the opening 3-3.
  • the planar shapes of the bottom 3-1 and the opening 3-3 are, for example, circular, but may be other shapes.
  • the solution storage space 3-4 has a first space 3-4-1 and a second space 3-4-2.
  • the first space 3-4-1 and the second space 3-4-2 have different diameters in a cross section perpendicular to the height direction from the bottom 3-1 to the opening 3-3 (hereinafter sometimes referred to as "the cross section").
  • the first space 3-4-1 and the second space 3-4-2 are connected side by side in the height direction from the bottom 3-1 to the opening 3-3.
  • the first space 3-4-1 is located on the bottom 3-1 side.
  • the second space 3-4-2 is located on the opening 3-3 side.
  • the cross-sectional shapes of the first space 3-4-1 and the second space 3-4-2 are, for example, circular, but may be other shapes.
  • the sidewall of the first space 3-4-1 may be perpendicular to the bottom 3-1 or may be inclined. If inclined, the diameter of the cross section of the first space 3-4-1 may be an average value. Furthermore, if it is inclined, the diameter of the cross section of the second space 3-4-2 can be an average value.
  • the diameter of the first space 3-4-1 in the cross section is indicated by D1
  • the diameter of the second space 3-4-2 in the cross section is indicated by D2 .
  • the diameter D1 of the first space 3-4-1 is smaller than the diameter D2 of the second space 3-4-2.
  • the ratio (diameter D 1 of the first space 3-4-1 at the cross section)/(diameter D 2 of the second space 3-4-2 at the cross section) may be 0.30 or more and 0.90 or less, preferably 0.65 or more and 0.90 or less, and more preferably 0.65 or more and 0.76 or less.
  • (height H 1 of the first space 3-4-1 in the height direction)/(height H 2 of the raw material solution 5 contained in the second space 3-4-2 in the height direction) is 0.2 or more and 0.8 or less.
  • the height direction is the direction from the bottom 3-1 toward the opening 3-3.
  • the diameter D1 of the first space 3-4-1 in the cross section is preferably larger than the diameter d1 of the seed crystal 9 (SiC seed crystal).
  • Figures 6(A) to (E) are crucibles 3 having a first space 3-4-1 and a second space 3-4-2 that are different in diameter.
  • Figure 6(A) is a crucible 3 that does not have a first space 3-4-1 and a second space 3-4-2 that are different in diameter.
  • the crucibles 3 in Figures 6(B) to (E) have different diameters of the first space 3-4-1.
  • the diameter of the first space 3-4-1 decreases in the order of Figure 6(B) ⁇ Figure 6(C) ⁇ Figure 6(D) ⁇ Figure 6(E).
  • the diameter of the first space 3-4-1 is larger than the diameter of the seed crystal 9. If the diameter of the first space 3-4-1 is smaller than the diameter of the seed crystal 9, it becomes difficult to supply solute to the outer periphery of the seed crystal 9, as shown in Figure 6 (E). As a result, more solute is supplied to the center, making it easier to obtain convex crystals. By making the diameter of the first space 3-4-1 larger than the diameter of the seed crystal 9, this inconvenience can be suppressed.
  • the shape of the resulting crystal can be adjusted by adjusting the diameter of the first space 3-4-1.
  • the crystal shape can be changed from concave to flat to convex.
  • “Growth method 3” Growth method 3 combines growth methods 1 and 2. That is, in growth method 3, a crystal is grown using the crystal growth apparatus 1 described in growth method 2. Furthermore, in growth method 3, as described in growth method 1, when the temperature of the raw material solution at the interface between the raw material solution and the seed crystal or the growth layer, where the temperature of a portion facing the center of the seed crystal or the growth layer is defined as a first temperature and the temperature of a portion facing the periphery of the seed crystal or the growth layer is defined as a second temperature, the absolute value of the value obtained by dividing the "temperature difference between the first temperature and the second temperature" by the "distance between the center and the periphery” is set to be 0.1 K/cm or less.
  • the method for manufacturing a SiC single crystal wafer of this embodiment includes a growing step S10 and a slicing step S11.
  • the growth step S10 is as described in the method for manufacturing a SiC single crystal ingot.
  • the SiC single crystal ingot of this embodiment described above is manufactured by the growth step S10.
  • SiC single crystal wafers are cut from the SiC single crystal ingot produced in the growth step S10. Through these steps, the SiC single crystal wafer of the present embodiment described above is produced. There are no particular restrictions on the method for cutting SiC single crystal wafers from the SiC single crystal ingot, and widely known techniques such as wire saw cutting and laser cutting can be used.
  • the film formation method includes a step of epitaxially forming a SiC film on a characteristic SiC single crystal wafer.
  • the SiC single crystal wafer includes at least one of the above-mentioned wafer features 1 to 7.
  • the SiC single crystal wafer may have a surface area Cr concentration of 1 ⁇ 10 15 atoms/cm 2 or less.
  • the SiC single crystal wafer may have a diameter of 4 inches or more and a volumetric Cr concentration of 1 ⁇ 10 16 atoms/cm 3 or more.
  • the volumetric Cr concentration in the SiC epitaxially grown film can be 1 ⁇ 10 15 atoms/cm 3 or less.
  • SiC single crystal features exemplified here are merely examples, and the SiC single crystal may have other features described above as wafer features 1 to 7.
  • the method for forming a SiC epitaxially grown film of this embodiment can be realized using widely known technology, except for the use of such a characteristic SiC single crystal.
  • Example 1 A 6-inch disk-shaped 4H-SiC single crystal (seed crystal) was attached to a graphite pulling shaft.
  • the seed crystal had a lower end surface that was the (000-1) plane, a deviation from the (000-1) plane of ⁇ 0.1° or less , a thickness of approximately 500 ⁇ m, a total thickness variation (TTV) of 7 ⁇ m or less, and a micropipe density of 0.07/cm2 or less.
  • a mixed raw material of silicon and chromium 40 mol% chromium
  • a Si-Cr-C solution containing dissolved graphite was prepared by holding the Si-Cr in a molten state in the graphite crucible.
  • the atmospheric gas was helium gas, and the pressure was 1 atmosphere.
  • the temperature of the radiation thermometer installed below the crucible axis, which measures the temperature at the bottom of the crucible reached 2050°C
  • the seed crystal attached to the pulling axis was brought into contact with the solution, and crystal growth on the seed crystal began.
  • the pulling axis and the crucible axis were rotated synchronously with a period of 82 seconds, with their rotation directions opposite each other.
  • the position of the pulling axis was adjusted during growth to allow crystal growth to proceed in the thickness direction.
  • the crystal was pulled out of the solution, and the furnace was cooled.
  • a 4H-SiC grown crystal with an average thickness of 10 mm was formed on the seed crystal, yielding a SiC single crystal ingot.
  • SiC single crystal wafers can be obtained by slicing this SiC single crystal ingot to the specified thickness.
  • the temperature distribution inside the growth furnace was analyzed using simulation software (COMSOL Multiphysics, COMSOL).
  • the analytical model was two-dimensionally axially symmetric, and a thermal fluid simulation was performed taking into account heat conduction, radiation, and convection. The calculation was time-dependent and terminated when the temperature reached a steady state.
  • the obtained ingot was sliced, and a 20 mm square piece was cut out from the center of the growth surface.
  • the (0001) plane side was polished, and the dislocation density was measured after KOH etching.
  • the etching temperature was 510°C and the treatment time was 10 minutes.
  • a digital microscope was used to observe the etch pits.
  • the type of dislocation was determined based on the shape of the etch pits. As a result, the TSD (threading screw dislocation) density was 7/ cm2 and the BPD (basal plane dislocation) density was 8/ cm2 .
  • Example 2 Crystal growth was carried out in the same manner as in Example 1, except that the output balance between the side heater and the bottom heater was changed. As a result, the "temperature difference between the first temperature and the second temperature" was -0.1 K, and the value obtained by dividing this by the "distance between the center and the outer periphery" was -0.013 K/cm. The thickness of the grown crystal was 10 mm.
  • the dislocation density was measured by the same method as in Example 1. As a result, the TSD (threading screw dislocation) density was 6/cm 2 , and the BPD (basal plane dislocation) density was 9/cm 2 .
  • Example 3 Crystal growth was performed in the same manner as in Example 2, except that the meniscus height was lower than in Example 2 and the growth time was longer. As a result, the "temperature difference between the first and second temperatures" was -0.1 K, and the value divided by the "distance between the center and the outer periphery" was -0.013 K/cm. The diameter of the grown crystal expanded to 8 inches, and the thickness of the grown crystal was 13 mm. Note that although the grown crystal was grown so that its diameter expanded, the thermal fluid simulation evaluated the state when the temperature distribution reached a steady state, and therefore evaluated it with the same diameter as the seed crystal.
  • the dislocation density was measured by the same method as in Example 1. As a result, the TSD (threading screw dislocation) density was 9/cm 2 , and the BPD (basal plane dislocation) density was 11/cm 2 .
  • Example 1 shows the evaluation results for Examples 1 to 3 and Comparative Example 1.
  • the seed crystals used were all the same, 6 inches.
  • the diameter of the grown crystals was 6 inches or more in all Examples 1 to 3 and Comparative Example 1, and the diameter of the grown crystal in Example 3 reached 8 inches.
  • ⁇ T is the temperature difference between the first temperature and the second temperature calculated in the simulation described above.
  • the first temperature is the temperature of the raw material solution at the interface between the raw material solution and the seed crystal or growth layer, and is the temperature of the location facing the center of the seed crystal or growth layer.
  • the second temperature is the temperature of the raw material solution at the interface between the raw material solution and the seed crystal or growth layer, and is the temperature of the location facing the outer periphery of the seed crystal or growth layer.
  • the absolute value of ⁇ T is 0.4 K or less, which is smaller than in Comparative Example 1.
  • ⁇ T per unit length is the value obtained by dividing " ⁇ T" by the “distance between the center and the outer periphery.” In Examples 1 to 3, the absolute value of ⁇ T per unit length is 0.1 K/cm or less, which is smaller than that of Comparative Example 1.
  • the interface shape is the shape of the surface (growth surface) of the growth layer at the interface between the growth layer and the raw material solution. Specifically, the growth surface of the growth layer (SiC single crystal ingot) in the as-grown state was evaluated.
  • the standard deviation of growth thickness is the "standard deviation of growth layer thickness" measured at 2 mm intervals from the center to the periphery of the surface of the as-grown growth layer.
  • the standard deviation of the grown crystal thickness is the "standard deviation of the grown crystal thickness" measured at 2 mm intervals from the center to the periphery of the surface of the grown crystal (a laminate of seed crystal and growth layer) in the as-grown state.
  • Comparative Example 1 where the "absolute value of ⁇ T" and “absolute value of ⁇ T per unit length” were relatively large and the uniformity of the temperature distribution was not improved, the interface shape was concave. In Comparative Example 1, the standard deviation of the growth thickness and the standard deviation of the grown crystal thickness were large, at over 300 ⁇ m.
  • the area ratio of solvent inclusions is the area ratio of the solvent inclusion region observed in an image taken of the surface of the growth layer of an as-grown SiC single crystal ingot to the growth surface.
  • Example 1 to 3 in which the temperature distribution at the interface between the raw material solution and the growth layer (or the seed crystal without a growth layer) was made more uniform, and the growth layer was grown while maintaining a more planar (closer to flat) growth surface, the above area ratio was sufficiently small, at 5% or less, preferably 1% or less. In other words, solvent inclusions were sufficiently reduced.
  • Comparative Example 1 in which the growth layer was not grown while maintaining the growth surface of the growth layer in a more planar (closer to flat) state, the above area ratio was greater than 5%, which was large. In other words, solvent inclusions were not reduced.
  • TSD Thireading Screw Dislocation
  • BPD Basal Plane Dislocation
  • SiC single crystal ingots of Examples 4 to 7 were produced as follows.
  • Example 4 A SiC single crystal ingot was produced using a crystal growth apparatus 1 as shown in Figure 5, which satisfied the following conditions: A crystal was grown in the same manner as in Example 1, except that the crystal growth apparatus was different.
  • the diameter D1 of the first space 3-4-1 in the cross section is 200 mm
  • the diameter D2 of the second space 3-4-2 in the cross section is 250 mm
  • Diameter D 1 / diameter D 2 is 0.8
  • the height H1 of the first space 3-4-1 in the height direction is 25 mm
  • the height H2 in the height direction of the raw material solution 5 contained in the second space 3-4-2 is 20 mm.
  • Example 5 A SiC single crystal ingot was produced in the same manner as in Example 4, except that a crystal growth apparatus 1 as shown in FIG. 5 was used, which satisfied the following conditions.
  • the diameter D1 of the first space 3-4-1 in the cross section is 180 mm
  • the diameter D2 of the second space 3-4-2 in the cross section is 250 mm
  • Diameter D 1 / diameter D 2 is 0.72
  • the height H1 of the first space 3-4-1 in the height direction is 25 mm
  • the height H2 in the height direction of the raw material solution 5 contained in the second space 3-4-2 is 20 mm.
  • Example 6 A SiC single crystal ingot was produced in the same manner as in Example 4, except that a crystal growth apparatus 1 as shown in FIG. 5 was used, which satisfied the following conditions.
  • the diameter D1 of the first space 3-4-1 in the cross section is 150 mm
  • the diameter D2 of the second space 3-4-2 in the cross section is 250 mm
  • Diameter D 1 / diameter D 2 is 0.6
  • the height H1 of the first space 3-4-1 in the height direction is 25 mm
  • the height H2 in the height direction of the raw material solution 5 contained in the second space 3-4-2 is 20 mm.
  • Example 7 A SiC single crystal ingot was produced in the same manner as in Example 4, except that a crystal growth apparatus 1 as shown in FIG. 5 was used, which satisfied the following conditions.
  • the diameter D1 of the first space 3-4-1 in the cross section is 120 mm
  • the diameter D2 of the second space 3-4-2 in the cross section is 250 mm
  • Diameter D 1 / diameter D 2 is 0.4
  • the height H1 of the first space 3-4-1 in the height direction is 25 mm
  • the height H2 in the height direction of the raw material solution 5 contained in the second space 3-4-2 is 20 mm.
  • Diameter of lower crucible in the table is diameter D1 in the cross section of the first space 3-4-1.
  • Diameter of lower stage/diameter of upper stage in the table is diameter D1 /diameter D2 .
  • the interface shape is the shape of the surface (growth surface) of the growth layer at the interface between the growth layer and the raw material solution. Specifically, the growth surface of the growth layer (SiC single crystal ingot) in the as-grown state was evaluated.
  • the “gentle concave” refers to a state in which concaves formed over the entire surface of the growth layer are observed, and no localized concaves are observed in a part of the surface of the growth layer.
  • “Flat” refers to a state in which the standard deviation of the grown crystal thickness is 50 ⁇ m or less.
  • the term “gentle convexity” refers to a state in which a convexity formed over the entire surface of the growth layer is observed. In other words, in a gentle convexity, a convexity that appears locally in a part of the surface of the growth layer is not observed.
  • “Locally centrally convex” refers to a state in which a locally convex shape is observed in a portion of the surface of the growth layer.
  • the standard deviation of growth thickness is the "standard deviation of growth layer thickness" measured at 2 mm intervals from the center to the periphery of the surface of the as-grown growth layer.
  • the standard deviation of the grown crystal thickness is the "standard deviation of the grown crystal thickness" measured at 2 mm intervals from the center to the periphery of the surface of the grown crystal (a laminate of seed crystal and growth layer) in the as-grown state.
  • the area ratio of solvent inclusions is the area ratio of the solvent inclusion region to the growth surface, as observed in an image of the surface of the growth layer of the as-grown SiC single crystal ingot, and was calculated using the same method as in Examples 1 to 3 and Comparative Example 1.
  • Examples 4 and 5 in which diameter D1 /diameter D2 was adjusted to 0.65 or more and 0.90 or less, the standard deviation of the growth thickness and the standard deviation of the grown crystal thickness were both 200 ⁇ m or less, which were sufficiently smaller than those of Examples 6 and 7, which did not satisfy this condition. That is, in Examples 4 and 5, the growth layer was grown while maintaining the growth surface in a state closer to a plane (closer to flatness) than those of Examples 6 and 7. Furthermore, in both of Examples 4 and 5, the area ratio of solvent inclusions was 1% or less, which was sufficiently smaller than those of Examples 6 and 7.
  • Example 5 in which diameter D1 /diameter D2 was adjusted to 0.65 or more and 0.76 or less, the standard deviation of the growth thickness and the standard deviation of the grown crystal thickness were both 100 ⁇ m or less, specifically 50 ⁇ m or less, more specifically 20 ⁇ m or less, which were sufficiently smaller than those of Examples 4, 6, and 7, which did not satisfy this condition. That is, in Example 5, the growth layer was grown while maintaining the growth surface in a state closer to a plane (closer to flatness) than those of Examples 2, 6, and 7. Furthermore, in Example 5, the area ratio of solvent inclusions was 0.5% or less, specifically 0.25% or less, more specifically 0.15% or less, which was sufficiently smaller than those of Examples 4, 6, and 7.
  • Table 2 shows that the interface shapes of Examples 4 to 7 change regularly with changes in diameter D1 /diameter D2 . That is, by adjusting diameter D1 /diameter D2 to 0.65 or more and 0.76 or less, the interface shape can be made flat. By making diameter D1 /diameter D2 greater than 0.76, the interface shape can be made concave. By making diameter D1 /diameter D2 smaller than 0.65, the interface shape can be made convex. The reason for this is thought to be due to the phenomenon described with reference to FIG. 6.
  • Example 5 Inidentally, ⁇ T and ⁇ T per unit length for Example 5 were calculated using the same methods as for Examples 1 to 3 and Comparative Example 1. ⁇ T was 0.7, and ⁇ T per unit length was 0.092 K/cm. In other words, Example 5 corresponds to Growth Method 3 described above. These results demonstrate that solvent inclusions can also be reduced using Growth Method 3, which combines Growth Methods 1 and 2.
  • Example 8 A SiC single crystal ingot was produced in the same manner as in Example 1, except that the seed crystal was 6 inches and the seed crystal attached to the pulling shaft was brought into contact with the solution when the temperature on the radiation thermometer reached 2070°C. A grown crystal of 4H—SiC with an average thickness of 2 mm was formed on the seed crystal, and a SiC single crystal ingot was obtained.
  • a thermal fluid simulation was performed on the temperature distribution in the solution during crystal growth, and the state in which the temperature distribution reached a steady state was evaluated.
  • the "temperature of the raw material solution at the interface between the raw material solution and the seed crystal or growth layer, where the temperature at the point facing the center of the seed crystal or growth layer is defined as the first temperature” and the “temperature at the point facing the periphery of the seed crystal or growth layer is defined as the second temperature” the "temperature difference between the first temperature and the second temperature” was -0.05 K, and the value divided by the "distance between the center and the periphery” was -0.007 K/cm.
  • the solvent inclusion ratio was determined using the same method as in Example 1. As a result, no inclusions were observed within the wafer surface, resulting in a ratio of 0%.
  • the dislocation density was measured by the same method as in Example 1. As a result, the TSD (threading screw dislocation) density was 5/cm 2 , and the BPD (basal plane dislocation) density was 5/cm 2 .
  • a wafer having a thickness of 500 ⁇ m was cut out from the growth layer, and the surface Cr concentration of the wafer was analyzed using a total reflection X-ray fluorescence analyzer (TXRF, Rigaku TXRF-3800e) and found to be 0.8 ⁇ 10 10 atoms/cm 2 .
  • TXRF total reflection X-ray fluorescence analyzer
  • This value met the acceptance criteria for equipment that grows epitaxial films on wafers. Therefore, if epitaxial growth of SiC is performed on this wafer, an epitaxially grown SiC film with a Cr concentration per volume of 1 ⁇ 10 15 atoms/cm 3 or less can be obtained.
  • a wafer with a thickness of 500 ⁇ m was cut out from the growth layer, and one point at the center of the wafer was measured by secondary ion mass spectrometry (SIMS, CAMECA IMS-7F, measurement conditions: primary ion species Cs+, primary ion energy 15.0 keV), and 1 ⁇ 10 17 atoms/cm 3 of Cr was detected.
  • SIMS secondary ion mass spectrometry
  • a SiC single crystal ingot in which the area ratio of solvent inclusion regions to the surface as observed in an image of the surface is 5% or less.
  • the SiC single crystal ingot according to 1 or 2 having a diameter of 6 inches or more.
  • the SiC single crystal ingot according to any one of 1 to 4 wherein the standard deviation of thickness measured at 2 mm intervals from the center toward the periphery of the surface in an as-grown state is 300 ⁇ m or less. 6.
  • a crystal growth device having a seed crystal and a growth layer in contact with the seed crystal, the seed crystal has a surface opposite to the surface in contact with the growth layer that is a flat surface; 7.
  • the SiC single crystal ingot according to 8 wherein (the total thickness of the seed crystal and the outer periphery of the growth layer in an as-grown state) ⁇ (the total thickness of the seed crystal and the central part of the growth layer in an as-grown state) is satisfied.
  • a SiC single crystal ingot according to any one of 1 to 10 wherein the surface area Cr concentration is 1 ⁇ 10 15 atoms/cm 2 or less. 10-2.
  • 14-2. A SiC single crystal wafer according to 14-1, having a Cr concentration per volume of 1 ⁇ 10 16 atoms/cm 3 or more.
  • a SiC single crystal wafer according to 14-3 having a Cr concentration per volume of 1 ⁇ 10 16 atoms/cm 3 or more.
  • the temperature of a portion facing the center of the SiC seed crystal or the growth layer is defined as a first temperature and the temperature of a portion facing the outer periphery of the SiC seed crystal or the growth layer is defined as a second temperature
  • the absolute value of the temperature difference between the first temperature and the second temperature divided by the distance between the center and the outer periphery is 0.1 K/cm or less.
  • a growth step of contacting a SiC seed crystal with a raw material solution containing Si and C to form a growth layer of a SiC single crystal on the surface of the SiC seed crystal In the growing step, a crucible having a solution containing space surrounded by a bottom, a sidewall, and an opening facing the bottom, the solution containing space containing the raw material solution; a chamber containing the crucible; a pulling shaft to which the SiC seed crystal having a diameter of 4 inches or more is attached; a heater for heating the raw material solution contained in the crucible; and
  • the solution-containing space of the crucible is a first space and a second space having different diameters in a cross section perpendicular to a height direction from the bottom portion toward the opening portion; the first space and the second space are arranged side by side in the height direction and connected to each other, A method for manufacturing a SiC single crystal ingot, which produces the growth layer using a manufacturing device in which the diameter of the cross section of the first space located on the bottom
  • the temperature of a portion facing the center of the SiC seed crystal or the growth layer is defined as a first temperature and the temperature of a portion facing the outer periphery of the SiC seed crystal or the growth layer is defined as a second temperature
  • the temperature of a portion facing the outer periphery of the SiC seed crystal or the growth layer is defined as a second temperature
  • a crucible having a solution containing space surrounded by a bottom, a sidewall, and an opening facing the bottom, wherein a raw material solution containing Si and C is contained in the solution containing space; a chamber containing the crucible; a pulling shaft to which a SiC seed crystal having a diameter of 4 inches or more is attached; a heater for heating the raw material solution contained in the crucible; and
  • the solution-containing space of the crucible is a first space and a second space having different diameters in a cross section perpendicular to a height direction from the bottom portion toward the opening portion; the first space and the second space are arranged side by side in the height direction and connected to each other, a diameter of the cross section of the first space located on the bottom side being smaller than a diameter of the cross section of the second space located on the opening side; 32.
  • 36. The apparatus for producing a SiC single crystal ingot according to any one of 31 to 35, wherein (height of the first space in the height direction)/(height of the raw material solution contained in the second space in the height direction) is 0.2 or more and 0.8 or less.
  • 37. The apparatus for producing a SiC single crystal ingot according to any one of 31 to 36, wherein the diameter of the SiC seed crystal is 6 inches or more. 38.
  • a method for forming a SiC epitaxially grown film comprising the step of epitaxially growing a SiC film on a SiC single crystal wafer having a surface area Cr concentration of 1 ⁇ 10 15 atoms/cm 2 or less.
  • 39. The method for forming a SiC epitaxially grown film according to 38, wherein the Cr concentration per volume in the SiC epitaxially grown film is 1 ⁇ 10 15 atoms/cm 3 or less.
  • Crystal growth device 3 Crucible 3-1 3-2 3-3 3-4 3-4-1 3-4-2 4 heater 5 raw material solution 6 radiation thermometer 7 pulling shaft 9 seed crystal 10 seed crystal 20 growth layer

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  • Crystals, And After-Treatments Of Crystals (AREA)

Abstract

Un lingot monocristallin de SiC selon la présente invention a un diamètre supérieur ou égal à 4 pouces, et a un rapport surfacique inférieur ou égal à 5 % par rapport à une surface d'une région d'inclusion de solvant observée dans une image capturée de la surface.
PCT/JP2025/018874 2024-05-31 2025-05-26 TRANCHE DE MONOCRISTAL DE SiC, LINGOT DE MONOCRISTAL DE SiC, PROCÉDÉ DE PRODUCTION DE TRANCHE DE MONOCRISTAL DE SiC, PROCÉDÉ DE PRODUCTION DE LINGOT DE MONOCRISTAL DE SiC, DISPOSITIF DE PRODUCTION DE LINGOT DE MONOCRISTAL DE SiC ET PROCÉDÉ DE FORMATION DE FILM FORMÉ PAR CROISSANCE ÉPITAXIALE DE SiC Pending WO2025249355A1 (fr)

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PCT/JP2025/018874 Pending WO2025249355A1 (fr) 2024-05-31 2025-05-26 TRANCHE DE MONOCRISTAL DE SiC, LINGOT DE MONOCRISTAL DE SiC, PROCÉDÉ DE PRODUCTION DE TRANCHE DE MONOCRISTAL DE SiC, PROCÉDÉ DE PRODUCTION DE LINGOT DE MONOCRISTAL DE SiC, DISPOSITIF DE PRODUCTION DE LINGOT DE MONOCRISTAL DE SiC ET PROCÉDÉ DE FORMATION DE FILM FORMÉ PAR CROISSANCE ÉPITAXIALE DE SiC

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006117441A (ja) * 2004-10-19 2006-05-11 Sumitomo Metal Ind Ltd 炭化珪素単結晶の製造方法
WO2014013773A1 (fr) * 2012-07-19 2014-01-23 トヨタ自動車株式会社 LINGOT DE MONOCRISTAL DE CARBURE DE SILICIUM (SiC) ET PROCÉDÉ DE PRODUCTION DE CE DERNIER
JP2020061562A (ja) * 2014-10-23 2020-04-16 住友電気工業株式会社 炭化珪素基板およびその製造方法
WO2024084910A1 (fr) * 2022-10-19 2024-04-25 住友電気工業株式会社 Substrat de carbure de silicium, procédé de fabrication d'un substrat épitaxial de carbure de silicium et procédé de fabrication d'un dispositif à semi-conducteur de carbure de silicium

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006117441A (ja) * 2004-10-19 2006-05-11 Sumitomo Metal Ind Ltd 炭化珪素単結晶の製造方法
WO2014013773A1 (fr) * 2012-07-19 2014-01-23 トヨタ自動車株式会社 LINGOT DE MONOCRISTAL DE CARBURE DE SILICIUM (SiC) ET PROCÉDÉ DE PRODUCTION DE CE DERNIER
JP2020061562A (ja) * 2014-10-23 2020-04-16 住友電気工業株式会社 炭化珪素基板およびその製造方法
WO2024084910A1 (fr) * 2022-10-19 2024-04-25 住友電気工業株式会社 Substrat de carbure de silicium, procédé de fabrication d'un substrat épitaxial de carbure de silicium et procédé de fabrication d'un dispositif à semi-conducteur de carbure de silicium

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
KUSUNOKI KAZUHIKO, SEKI KAZUAKI , KISHIDA YUTAKA, MORIGUCHI KOJI, KAIDO HIROSHI, OKADA NOBUHIRO, KAMEI KAZUHITO: "Development of High Quality 4H-SiC Single Crystal Wafers Grown by Solution Growth Technique", NIPPON STEEL & SUMITOMO METAL TECHNICAL REPORT, vol. 2017, no. 407, 1 January 2017 (2017-01-01), JP, pages 50 - 57, XP093377240 *

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