JP2006273585A - Apparatus for manufacturing single crystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly grow a single crystal on a seed crystal in manufacturing the single crystal by a vapor phase deposition. <P>SOLUTION: The apparatus for manufacturing a single crystal 10 is equipped with a seed crystal 3, a container 1 which contains a raw material 5 of a single crystal 6, a main body 21 which composes a furnace 2 containing the seed crystal 3 and the container 1, a lid 22, and a holder 23, and the single crystal 6 is manufactured by a vapor phase deposition. At least a part of the opening forming part A of the container 1 is formed by a material having a crystal system different from the crystal system of the single crystal 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a single crystal manufacturing apparatus for manufacturing a single crystal by a vapor phase method.

There are various methods for producing a single crystal, such as a gas phase method and a liquid phase method. In general, these production methods involve preparing a seed crystal and growing a single crystal on the seed crystal. For example, single crystal production by a vapor phase method is performed in a single crystal production apparatus including a seed crystal, a container containing single crystal raw materials, and a furnace containing these (for example, Non-Patent Document 1, Non-patent Document 1). Patent Document 2).
Cengiz M. etal, “Sublimation growth and characterization of bulk aluminum nitride single crystals”, Journal of Crystal Growth 179, 1997, p.363-370 Glen A. Slack, “Growth of Single Crystals”, Mat. Res. Soc. Symp. Proc. Vol. 512, 1998, p.

  However, conventional single-phase production equipment for vapor-phase methods produces not only seed crystals but also miscellaneous crystals (crystals) on the vessel that contains the raw material of the single crystal and on the furnace material that constitutes the furnace. There was a problem to do. As a result, the production yield of the single crystal is reduced. In particular, miscellaneous crystals formed on the container may block the opening of the container. As a result, the raw material accommodated in the container could hardly reach the seed crystal, and the yield of the single crystal might be very low.

  Moreover, since the container and furnace material in which the raw material of a single crystal is accommodated are exposed to a very reactive environment, their deterioration was severe. Therefore, the life of the container and the furnace material is short, and there is a possibility that the dissolved components of the container and the furnace material are mixed into the single crystal as impurities.

  Accordingly, an object of the present invention is to appropriately grow a single crystal on a seed crystal in the production of a single crystal using a vapor phase method.

  The single crystal manufacturing apparatus of the present invention includes a seed crystal, a container for storing the raw material of the single crystal, and a furnace material constituting a furnace for storing the seed crystal and the container, and manufactures the single crystal by a vapor phase method. To do. The single crystal manufacturing apparatus is characterized in that at least a part forming the opening of the container is formed of a crystal material different from the crystal system of the single crystal.

  According to such a single crystal manufacturing apparatus, at least a part of the container for storing the raw material of the single crystal is formed of a crystal material different from the target single crystal crystal system. Therefore, it can suppress that a miscellaneous crystal produces | generates in the part which forms the opening part of a container. Therefore, the raw material accommodated in the container becomes a gas phase and can reach the seed crystal. As a result, the single crystal can be appropriately grown on the seed crystal in the production of the single crystal using the vapor phase method.

  It is preferable that a material having a crystal system different from the crystal system of the single crystal does not have a lattice plane having good consistency with the growth surface of the single crystal to be manufactured and has poor wettability with the single crystal.

  Furthermore, it is preferable that at least a part of the peripheral portion of the seed crystal of the furnace material is formed of a crystal material different from the single crystal crystal system. According to this, since it is possible to suppress generation of miscellaneous crystals on the furnace material, it is possible to grow a single crystal on the seed crystal more reliably and to improve the manufacturing yield.

  The material having a crystal system different from the crystal system of the single crystal is preferably a nitride. According to this, it is possible to suppress deterioration of the container or furnace material in which the single crystal raw material is stored. Therefore, the life of the container and the furnace material can be extended, and impurities can be prevented from being mixed into the single crystal. The material having a crystal system different from the single crystal system is preferably titanium nitride or zirconium nitride.

  The single crystal to be produced is preferably a hexagonal system. The hexagonal single crystal is preferably aluminum nitride or silicon carbide.

  As described above, according to the present invention, a single crystal can be appropriately grown on a seed crystal in the production of a single crystal using a vapor phase method.

  As shown in FIG. 1, the single crystal manufacturing apparatus 10 includes a container 1 in which a single crystal raw material is stored, a furnace 2, a seed crystal 3, and a heater 4. The single crystal manufacturing apparatus 10 grows the single crystal 6 on the seed crystal 3 and manufactures the single crystal 6. The single crystal manufacturing apparatus 10 manufactures the single crystal 6 by a sublimation method that is one of gas phase methods.

  In the container 1, a raw material 5 of the single crystal 6 is accommodated. The container 1 has an opening. The raw material 5 accommodated in the container 1 becomes a gas phase, and exits from the opening of the container 1 toward the seed crystal 3. The furnace 2 includes a main body portion 21 having an opening portion, a lid portion 22 that closes the opening portion of the main body portion 21, and a holding portion 23. The main body 21 accommodates the container 1. The holding unit 23 holds the seed crystal 3. The holding part 23 is attached to the lid body part 22. The lid portion 22 is disposed so as to close the opening of the main body portion 21 in a state where the seed crystal 3 is held by the holding portion 23. In this way, the container 1 and the seed crystal 3 are accommodated in the furnace 2. At the same time, the seed crystal 3 is disposed above the container 1 so as to face the container 1.

  The heater 4 is provided around the furnace 2 and heats the inside of the furnace 2. By heating by the heater 4, the raw material 5 accommodated in the container 1 is sublimated, and a single crystal 6 grows on the seed crystal 3. As the heater 4, a carbon heater, a tungsten heater, or the like can be used. Such a single crystal manufacturing apparatus 10 includes, for example, a reaction chamber (chamber) that can be evacuated, an inert gas such as nitrogen gas or argon gas, and a reaction that can introduce a compound gas according to the type of single crystal. It can be accommodated in a chamber. Further, a heat insulating material can be provided around the furnace 2.

  Next, the container 1 and the furnace 2 will be described in more detail. In the container 1, at least a part of a portion (hereinafter referred to as “opening forming portion”) A that forms the opening is formed of a material having a crystal system different from the crystal system of the target single crystal 6. Further, among the furnace materials such as the main body 21, the lid portion 22, and the holding portion 23 constituting the furnace 2, at least a part of the peripheral portion of the seed crystal 3 (hereinafter referred to as “seed crystal peripheral portion”) B is a single part. The crystal 6 is made of a material different from the crystal system.

  The crystal system includes triclinic system, monoclinic system, tetragonal system, hexagonal system, trigonal system and cubic system. For example, when the single crystal 6 is hexagonal, at least part of the opening forming part A of the container 1 and the seed crystal peripheral part B of the furnace material is triclinic, monoclinic, other than hexagonal, A tetragonal, trigonal, or cubic crystal material can be used.

  It is preferable that a material having a crystal system different from the crystal system of the single crystal does not have a lattice plane having good consistency with the growth surface of the single crystal to be manufactured and has poor wettability with the single crystal.

  The crystal material different from the crystal system of the single crystal 6 is preferably a nitride. According to this, deterioration of the container 1 and the furnace material can be suppressed. Therefore, the lifetime of the container 1 and the furnace material can be extended, and impurities can be prevented from being mixed into the single crystal 6. More specifically, many nitrides are stable even at high temperatures, and hardly react with single crystal components or raw material components stored in the container 1. Therefore, by forming at least a part of the opening forming part A of the container 1 and the seed crystal peripheral part B of the furnace material, to which the sublimated raw material components are likely to adhere, the container 1 and the furnace material can be used for a long time. It can withstand the growth of the single crystal and can suppress the components of the vessel 1 and the furnace material from becoming impurities mixed into the single crystal. Therefore, the single crystal manufacturing apparatus 10 can grow a single crystal for a long time, and can manufacture a single crystal with less impurities. In particular, it is preferable to use titanium nitride (TiN) or zirconium nitride (ZrN) as the nitride.

  The single crystal manufacturing apparatus 10 can manufacture ceramic single crystals. For example, the single crystal manufacturing apparatus 10 can manufacture a single crystal of a hexagonal ceramic. The single crystal manufacturing apparatus 10 can manufacture, for example, aluminum nitride (AlN), silicon carbide (SiC), gallium nitride (GaN), etc. as a single crystal of hexagonal ceramics.

  When producing a single crystal such as hexagonal aluminum nitride or silicon carbide, at least part of the opening forming portion A of the container 1 and the seed crystal peripheral portion B of the furnace material is different from the crystal system of the single crystal 6. It is preferable to use cubic system titanium nitride (TiN) or zirconium nitride (ZrN) as the system material.

In addition to the crystal system of the single crystal 6, the material for forming at least a part of the opening forming part A of the container 1 and the seed crystal peripheral part B of the furnace material is based on the raw material 5 used for manufacturing the single crystal 6. It is preferable to use an optimum one. For example, when a single crystal of aluminum nitride is manufactured, at least one of aluminum nitride or an aluminum nitride precursor can be used as the raw material. Furthermore, a raw material in which at least one of aluminum nitride or an aluminum nitride precursor is mixed with at least one of aluminum oxide (Al ₂ O ₃ ) or an aluminum oxide precursor may be used. Alternatively, at least one of aluminum oxynitride (AlON) or aluminum oxynitride precursor can be used.

Examples of the precursor of aluminum oxide include aluminum hydroxide (Al (OH) ₃ ), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), aluminum alkoxide (Al (RO) ₃ , R) that changes to aluminum oxide by heating. : Alkyl group) and the like. The precursor of aluminum nitride, for example, aluminum is changed to aluminum oxide by heating (Al), aluminum carbide _{(Al 4 C 3, Al 2} C 6), boehmite _{(AlO (OH), Al 2} O 3 · H 2 O), aluminum chloride (AlCl ₃ ), or the like can be used.

When a silicon carbide single crystal is produced, silicon carbide, silica (SiO ₂ ) and carbon (C), silicon (Si), carbon, and the like can be used as the raw material.

  For example, when producing a single crystal of aluminum nitride, when at least one of aluminum nitride or an aluminum nitride precursor is used alone as the raw material 5, aluminum (Al) is volatilized from the raw material during the production of the single crystal. Therefore, at least a part of the opening forming portion A of the container 1 and the seed crystal peripheral portion B of the furnace material is a nitride that is more stable than aluminum nitride in terms of free energy, and is made of a material having a crystal system different from that of aluminum nitride. It is preferable to form. For example, it is preferable that at least a part of the opening forming part A of the container 1 and the seed crystal peripheral part B of the furnace material is formed of titanium nitride or zirconium nitride.

Further, when producing a single crystal of aluminum nitride, when using a mixture of at least one of aluminum oxide or aluminum oxide precursor and at least one of aluminum nitride or aluminum nitride precursor as raw material 5, When aluminum oxynitride is used, it is believed that lower oxides of aluminum (eg, Al ₂ O) are volatilized from the raw material during single crystal production. Therefore, at least a part of the forming material of the opening forming part A of the container 1 and the seed crystal peripheral part B of the furnace material is a nitride that is more stable than aluminum nitride in terms of free energy and is included in the forming material. The oxide generated from the metal element is more unstable than aluminum oxide and preferably has a crystal system different from that of aluminum nitride. For example, it is preferable that at least a part of the opening forming part A of the container 1 and the seed crystal peripheral part B of the furnace material is formed of titanium nitride.

  As shown in FIG. 1, at least a part of the opening forming portion A of the container 1 may be formed of a crystal material different from the crystal system of the single crystal 6. For example, as shown in FIG. 2A, the entire opening forming portion 1 a of the container can be formed of a material having a crystal system different from that of the single crystal 6. Further, as shown in FIG. 2B, a part of the opening forming part of the container can be formed with a coating layer 1 c made of a crystal material different from the single crystal 6. For example, the inner wall and the end of the opening forming portion of the container, to which the sublimated raw material easily adheres, can be formed with the coating layer 1c.

  As shown in FIG. 1, the furnace material may be formed of a material having a crystal system different from the crystal system of the single crystal 6 in at least a part of the seed crystal peripheral portion B of the furnace material. For example, a furnace material in the range of a circle having a radius 1.5 times the radius (inner diameter) of the opening of the container 1 with the seed crystal 3 as the center is formed of a material of a crystal system different from the single crystal 6. can do. In addition, the portion where the sublimated raw material easily adheres in the seed crystal peripheral portion B of the furnace material can be formed of a material of a crystal system different from that of the single crystal 6.

  For example, as shown in FIG. 2C, the entire seed crystal peripheral part such as the central part 22 a and the holding part 23 of the lid part 22 can be formed of a material having a crystal system different from that of the single crystal 6. Further, as shown in FIG. 2 (d), a part of the seed crystal peripheral part such as the lower part of the central part of the lid part 22 can be formed with a coating layer 22 c made of a crystal material different from the single crystal 6. .

  The material of the raw material container 1b that stores the raw material of the container and the main body 1d that supports the coating layer 1c is not limited. Moreover, the material of the outer peripheral part 22b surrounding the outer periphery of the center part 22a of the lid part 22 and the main body part 22d for supporting the coating layer 22c is not limited.

  For example, the container raw material storage portion 1b and the main body portion 1d, the outer peripheral portion 22b and the main body portion 22d of the lid body portion 22, the container opening forming portion 1a and the covering layer 1c, the central portion 22a of the lid portion 22 and the covering layer. It can be formed of the same material as 22c. In this case, the entire container in which the single crystal raw material is accommodated and the entire furnace material (cover body portion 22) are formed of a crystal material different from the crystal system of the single crystal 6. For example, when a nitride such as titanium nitride or zirconium nitride is used as a material having a crystal system different from that of a single crystal, deterioration of the entire container and the entire furnace material can be suppressed. The length can be increased, and impurities can be further prevented from being mixed into the single crystal. The same effect can be obtained by forming the entire inner wall of the container with the covering layer, or forming the entire portion facing the container of the furnace material (the entire lower portion of the lid portion 22) with the covering layer.

  Alternatively, the raw material container 1b and the main body 1d of the container and the outer peripheral portion 22b and the main body 22d of the lid 22 may be formed of boron nitride (BN), aluminum nitride, carbon (C), or the like. According to this, when the material of the crystal system different from the single crystal 6 is weak against thermal shock or when the difference from the thermal expansion coefficient of the single crystal 6 is large, the raw material container 1b and the main body 1d of the container are used. The outer peripheral portion 22b and the main body portion 22d of the lid portion 22 can reinforce the opening forming portion 1a and the covering layer 1c of the container, and the central portion 22a and the covering layer 22c of the lid portion 22. Therefore, the life of the container and the furnace material can be further increased. For example, the raw material container 1b and the main body 1d of the container, the outer peripheral part 22b and the main body 22 of the lid 22 are made of aluminum nitride, and the opening forming part 1a, the covering layer 1c, and the lid 22 of the container are formed. The central portion 22a and the covering layer 22c can be formed of titanium nitride.

  In the case where the entire container 1 and the entire lid part 22 are formed of a material having a crystal system different from the single crystal 6, the container 1 and the lid part 22 can be produced by adjusting and shaping the raw material powder and firing it. In addition, when a part of the container 1 or the lid part 22 is formed of a crystal material different from the single crystal 6 and the remaining part is formed of another material, first, the respective raw material powders are adjusted and molded. Create a plurality of molded bodies. Thereafter, each molded body is fired, and the plurality of obtained sintered bodies are bonded by, for example, a liquid phase bonding method or a solid phase bonding method using a bonding agent, thereby producing the container 1 and the lid portion 22. it can. Alternatively, by integrally firing a plurality of molded bodies by a hot press method or the like, the integrally sintered container 1 and the lid portion 22 can be produced.

  When the coating layers 1c and 22c are formed on the main body portions 1d and 22d, the main body portions 1d and 22d are first prepared by adjusting and forming the raw material powders of the main body portions 1d and 22d and firing them. . Next, the coating layers 1c and 22c can be formed on the main body portions 1d and 22d by, for example, CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), or the like. The thickness of the coating layers 1c and 22c is preferably 1 to 20 μm.

  Furthermore, the average particle diameter of the portion formed of a crystal material different from the single crystal 6 of the opening forming portion A of the container 1 and the seed crystal peripheral portion B of the furnace material is 0.5 to 10 μm. preferable. Further, the surface roughness (Ra) of the portion formed of a crystal system material different from the single crystal 6 of the opening forming portion A of the container 1 and the seed crystal peripheral portion B of the furnace material may be 20 μm or less. preferable. According to these, generation of miscellaneous crystals can be further suppressed, and deterioration of the container 1 and the furnace material can be further suppressed.

  Furthermore, the pore diameter of the portion formed of a crystal material different from the single crystal 6 of the opening forming portion A of the container 1 and the seed crystal peripheral portion B of the furnace material is preferably 20 μm or less. Moreover, it is preferable that the porosity of the part formed with the crystal system material different from the single crystal 6 of the opening part formation part A of the container 1 and the seed crystal peripheral part B of the furnace material is 10% or less. According to these, deterioration of the container 1 and the furnace material can be further suppressed.

  According to such a single crystal manufacturing apparatus 10, at least a part of the opening forming part A of the container 1 in which the single crystal raw material is accommodated is made of a crystal material different from the target crystal system of the single crystal 6. Since it is formed, generation of miscellaneous crystals in the opening forming portion A of the container 1 can be suppressed. Therefore, the miscellaneous crystal does not block the opening of the container 1, and the raw material 5 accommodated in the container 1 becomes a vapor phase and can reach the seed crystal 3. As a result, the single crystal 6 can be appropriately grown on the seed crystal 3 in the production of the single crystal 6 using the vapor phase method. Therefore, the yield of the single crystal 6 can be improved and the manufacturing yield can be improved.

  Further, among the furnace materials such as the main body portion 21, the lid body portion 22, and the holding portion 23 constituting the furnace 2, at least a part of the seed crystal peripheral portion B is made of a crystal material different from the crystal system of the single crystal 6. Since it is formed, generation of miscellaneous crystals on the furnace material can also be suppressed. Therefore, the single crystal 6 can be more reliably grown on the seed crystal 3, and the manufacturing yield can be further improved.

  In addition, this invention is not limited to the said embodiment, A various change is possible. For example, as the furnace material constituting the furnace 2, there are a support base for supporting the container 1, a taper for efficiently separating the space where the single crystal 6 is generated and the space where the miscellaneous crystals are attached. is there. Further, materials other than the seed crystal peripheral portion B of the furnace material, for example, the material of the main body portion 21 are not limited, and can be the same as, for example, the outer peripheral portion 22b and the main body portion 22d of the lid portion 22 shown in FIG. Moreover, by forming the upper part of the main body 21 above the container 1 with a crystal material different from the single crystal 6, it is possible to more reliably prevent the sublimated raw material from reaching the furnace material.

  Moreover, although the said embodiment demonstrated the case where a single crystal was manufactured by the sublimation method which is one of the gas phase methods, the single crystal manufacturing apparatus of this invention can be used for all the gas phase methods. For example, the present invention can be applied to the case of producing a single crystal by a vapor phase method such as a chemical transport method other than the sublimation method or a chemical vapor phase synthesis method.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to the following Example at all.

(Example 1, Comparative Examples 1-3)
As Example 1, a container containing a single crystal raw material formed entirely of titanium nitride including an opening forming portion was prepared. Specifically, titanium nitride powder having a particle size distribution of 0.5 to 2 μm was molded at a pressure of 20 MPa by a mold molding method. The molded body was fired at 1800 ° C. by hot pressing in nitrogen gas. The obtained sintered body was ground to obtain a container.

  Further, as Comparative Examples 1 to 3, a container formed entirely of graphite including the opening forming part (Comparative Example 1), a container formed of boron nitride (Comparative Example 2), a container formed of aluminum nitride (Comparative Example) 3) was prepared.

The raw material 5 which mixed 35 mol% aluminum nitride and 65 mol% aluminum oxide was accommodated in the container, and it arrange | positioned in the main-body part 21 of the furnace 2 shown in FIG. The seed crystal 3 of aluminum nitride was held by the holding part 23, and the lid part 22 was arranged so as to close the opening part of the main body part 21. Furthermore, the single crystal manufacturing apparatus 10 was accommodated in a reaction chamber, and after reducing the pressure in the reaction chamber to 5 × 10 ⁻⁴ Pa, nitrogen gas was introduced. And it heated up to 2200 degreeC with the temperature increase rate of 20 degree-C / min, and hold | maintained at 2200 degreeC for 2 hours, and manufactured the hexagonal-type aluminum nitride single crystal.

About the container of Example 1 and Comparative Examples 1-3, the production | generation condition of the miscellaneous crystal, the reaction condition with the raw material of a single crystal, and the degradation condition were observed. In addition to observation, the deterioration state was measured by measuring the weight of the container before manufacturing the single crystal and the weight of the container after manufacturing the single crystal, and evaluating the decrease due to deterioration. Furthermore, the state of impurity contamination in the obtained single crystal was observed. The evaluation results are shown in Table 1. Moreover, the state (state which observed the container from the upper direction) of the container of Example 1 after Comparative Example 1-3 after manufacture of a single crystal and the state is shown in FIGS. 3-6, respectively.

  In the container (Example 1) formed of cubic titanium nitride different from the aluminum nitride single crystal, no miscellaneous crystals were generated in the opening forming part of the container as shown in FIG. Moreover, there was no reaction with the raw material, no weight loss, and almost no deterioration was observed. Furthermore, no impurities were mixed in the obtained single crystal, and a high-purity aluminum nitride single crystal could be produced with high yield.

  On the other hand, in the container (Comparative Example 1) formed of the same hexagonal graphite as the aluminum nitride single crystal, a large amount of miscellaneous crystals were generated in the opening forming part of the container as shown in FIG. . Moreover, it reacted with the raw material aluminum oxide, and the weight loss was large and the deterioration was severe. Further, the obtained single crystal was colored blue as a whole, and a large amount of impurities were mixed therein. Moreover, the yield of the single crystal was low and the yield was low.

  Further, in the container formed of the same hexagonal boron nitride as the aluminum nitride single crystal (Comparative Example 2), as shown in FIG. 5, miscellaneous crystals are generated along the inner wall of the opening forming portion of the container. It was. Also, it reacted with the raw material aluminum oxide, resulting in a decrease in weight and deterioration. Furthermore, the surface of the obtained single crystal was colored yellow, and impurities were mixed.

  Furthermore, in the container formed of aluminum nitride (Comparative Example 3), as shown in FIG. 6, a large amount of miscellaneous crystals were generated, and the opening of the container was completely closed. Also, it reacted with the raw material aluminum oxide, resulting in a decrease in weight and deterioration. Although no impurities were mixed, the yield of the single crystal was very low and the yield was extremely low.

It is sectional drawing which shows the single crystal manufacturing apparatus which concerns on embodiment of this invention. It is a figure which shows the container and furnace material which concern on embodiment of this invention. FIG. 3 is a top view showing a state of the opening of the container of Example 1. 6 is a top view showing a state of an opening of a container of Comparative Example 1. FIG. 6 is a top view showing a state of an opening of a container of Comparative Example 2. FIG. It is a top view which shows the state of the opening part of the container of the comparative example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Furnace 3 Seed crystal 4 Heater 5 Raw material 6 Single crystal 10 Single crystal manufacturing apparatus 21 Main part 22 Lid part 23 Holding part

Claims (7)

A single crystal manufacturing apparatus comprising a seed crystal, a container for storing a raw material of the single crystal, and a furnace material constituting a furnace for storing the seed crystal and the container, and manufacturing the single crystal by a vapor phase method. There,
An apparatus for producing a single crystal, characterized in that at least a part forming the opening of the container is made of a crystal material different from the crystal system of the single crystal.   2. The material according to claim 1, wherein a material having a crystal system different from the crystal system of the single crystal does not have a lattice plane having good consistency with a growth surface of the single crystal, and has poor wettability with the single crystal. Single crystal manufacturing equipment.   3. The single crystal manufacturing apparatus according to claim 1, wherein at least a part of a peripheral portion of the seed crystal of the furnace material is formed of a material having a crystal system different from the crystal system of the single crystal. .   The single crystal manufacturing apparatus according to any one of claims 1 to 3, wherein the material having a crystal system different from the crystal system of the single crystal is a nitride.   The single crystal manufacturing apparatus according to claim 4, wherein the material having a crystal system different from the crystal system of the single crystal is titanium nitride or zirconium nitride.   The single crystal manufacturing apparatus according to claim 1, wherein the single crystal is a hexagonal system. The single crystal manufacturing apparatus according to claim 6, wherein the single crystal is aluminum nitride or silicon carbide.

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