JP2013107786A - Method for producing silicon carbide single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a silicon carbide single crystal stably by controlling growth speed of the silicon carbide single crystal, concerning the method for producing a silicon carbide single crystal by using a metastable solvent epitaxy method.SOLUTION: Concerning the method for producing a silicon carbide single crystal by using a metastable solvent epitaxy method for growing a silicon carbide single crystal on the surface of a silicon carbide single crystal material 20, in an arrangement step S2, one material of a material of the silicon carbide single crystal material 20 and a silicon carbide supply material 40 is arranged on the upper side of a silicon material 60, and the position of the one material is fixed, and the silicon material 60 is interposed between the silicon carbide single crystal material 20 and the silicon carbide supply material 40.

Description

  The present invention relates to a method for producing a silicon carbide single crystal using a metastable solvent epitaxy method.

  As a method for producing a silicon carbide single crystal, a method using a metastable solvent epitaxy method (MSE method) is known (for example, see Patent Document 1). When a silicon carbide single crystal is manufactured using the MSE method, a single crystal substrate made of silicon carbide single crystal, a polycrystalline substrate made of silicon carbide polycrystal, and a silicon substrate made of silicon are prepared. A polycrystalline substrate, a silicon substrate, and a single crystal substrate are sequentially stacked on the bottom of a heat-resistant container. The container in which the material is placed is heated at a temperature equal to or higher than the temperature at which the silicon substrate melts. By heating, the silicon substrate melts and changes into a silicon melt layer. Carbon dissolves from the single crystal substrate and the polycrystalline substrate into the silicon melt layer. Since the polycrystalline substrate has a higher chemical potential than the single crystal substrate, a carbon concentration gradient occurs in the silicon melt layer. Using this concentration gradient as a driving force, the carbon dissolved in the silicon melt layer moves from the polycrystalline substrate side to the single crystal substrate side. The carbon that has moved to the single crystal substrate side is bonded to silicon on the single crystal substrate. Thereby, a silicon carbide single crystal is deposited on the surface of the single crystal substrate, and a silicon carbide single crystal grows. In this way, a silicon carbide single crystal can be produced.

  According to the MSE method, the growth of the silicon carbide single crystal uses the concentration gradient as a driving force, and the growth of the silicon carbide single crystal does not depend on the temperature gradient. Therefore, compared to the sublimation recrystallization method in which the heating temperature needs to be adjusted depending on the location, the process control becomes easier and a silicon carbide single crystal with good quality can be obtained.

JP 2008-230946 A

  However, when a silicon carbide single crystal is manufactured using the above-described manufacturing method, the growth rate of the silicon carbide single crystal is unstable, and the growth height of the manufactured silicon carbide single crystal is different each time it is manufactured. There was a thing. That is, even if the growth time of the silicon carbide single crystal is constant, the growth height of the silicon carbide single crystal may vary. The method for producing a silicon carbide single crystal in which the growth height varies is practically problematic. For this reason, there has been a demand for a method capable of stably producing a silicon carbide single crystal by controlling the growth rate of the silicon carbide single crystal.

  Therefore, the present invention has been made in view of such a situation. In a method for producing a silicon carbide single crystal using a metastable solvent epitaxy method, the growth rate of the silicon carbide single crystal is controlled, and the silicon carbide single crystal is controlled. An object is to provide a method capable of stably producing crystals.

  As a result of intensive studies by the inventors, it has been found that the thickness of the silicon melt layer changes and the growth rate changes depending on the weight of the material disposed on the upper side in the gravity direction of the silicon melt layer. Therefore, the present inventor has completed the present invention having the following features in order to solve the above-described problems.

  A feature of the present invention is that a silicon carbide single crystal material (silicon carbide single crystal material 20) made of a silicon carbide single crystal and a carbon silicon supply material (carbon) made of silicon carbide having a larger chemical potential than the silicon carbide single crystal material. A preparation step (preparation step S1) for preparing a silicon supply material 40) and a silicon material made of silicon (silicon material 60), the silicon carbide single crystal material, the carbon silicon supply material, and the silicon material in a container An arrangement step (arrangement step S2) to arrange, and a heating step (heating step S3) for heating the container at a temperature not lower than a temperature at which the silicon material melts and lower than a temperature at which the silicon material boils. A silicon carbide single crystal manufacturing method using a metastable solvent epitaxy method for growing a silicon carbide single crystal on a surface of a silicon single crystal material, wherein the silicon carbide single crystal is formed in the arranging step. Either the material or the carbon silicon supply material is disposed on the upper side of the silicon material, the position of the one material is fixed, and the silicon carbide single crystal material and the carbon silicon supply material The gist is to interpose a silicon material.

  According to the feature of the present invention, either the silicon carbide single crystal material or the carbon silicon supply material is disposed on the upper side of the silicon material, and the position of the one material is fixed. For example, when the carbon silicon supply material is disposed on the upper side of the silicon material, the position of the carbon silicon supply material is fixed. For this reason, even if the force which goes to the silicon molten layer side (namely, lower side) acts on a carbon silicon supply material by gravity, a carbon silicon supply material does not move to the silicon molten layer side. Therefore, even if the silicon material is melted by the heating process to form a silicon melt layer, the pressure applied from the carbon silicon supply material to the silicon melt layer is suppressed. Furthermore, even if the weight of the carbon silicon supply material is reduced by supplying carbon and silicon to the silicon melt layer by the carbon silicon feed material, a change in pressure applied to the silicon melt layer is suppressed. Therefore, a change in the thickness of the silicon melt layer due to the weight of the carbon silicon supply material can be suppressed. Since the thickness of the silicon melt layer depends on the growth rate, the growth rate of the silicon carbide single crystal can be controlled by suppressing the change in the thickness of the silicon melt layer. As a result, the silicon carbide single crystal can be manufactured more stably than in the past.

  Even when the silicon carbide single crystal material is disposed on the upper side of the silicon material, the pressure applied to the silicon melt layer from the silicon carbide single crystal material is similarly suppressed. Furthermore, even if the weight of the silicon carbide single crystal material increases due to the growth of the silicon carbide single crystal material on the silicon carbide single crystal material, a change in pressure applied to the silicon melt layer is suppressed. It can suppress that the pressure by the weight of a silicon carbide single-crystal material is added to a silicon molten layer. Therefore, a change in the thickness of the silicon melt layer can be suppressed, and the growth rate of the silicon carbide single crystal can be controlled. As a result, the silicon carbide single crystal can be manufactured more stably than in the past.

  In the arranging step, the one material is fixed to the container, and the other material different from the one material of the silicon carbide single crystal material or the carbon silicon supply material is set to the bottom of the container rather than the one material. It may be arranged on the side.

  The carbon silicon supply material may be made of polycrystalline silicon carbide.

  The molar ratio of silicon to carbon in the carbon silicon supply material may be 1.00 or more.

  The relative density of the carbon silicon feed may be greater than 95%.

  You may provide the silicon evaporation process (silicon evaporation process S4) which heats the said container more than the temperature heated in the said heating process, and evaporates the said silicon material.

  According to the present invention, in a method for producing a silicon carbide single crystal using a metastable solvent epitaxy method, it is possible to continuously produce a silicon carbide single crystal while suppressing a decrease in the thickness of the silicon melt layer.

FIG. 1 is a flowchart for explaining a method for manufacturing a silicon carbide single crystal according to the present embodiment. FIG. 2 is a schematic cross-sectional view of the container 10 used in the method for manufacturing a silicon carbide single crystal according to the present embodiment.

  An example of a silicon carbide single crystal manufacturing apparatus and a silicon carbide single crystal manufacturing method according to the present invention will be described with reference to the drawings. Specifically, (1) a method for producing a silicon carbide single crystal, (2) operational effects, (3) examples, and (4) other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. It should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings may be contained.

(1) Manufacturing method of silicon carbide single crystal The manufacturing method of the silicon carbide single crystal which concerns on this embodiment is demonstrated referring FIG.1 and FIG.2. FIG. 1 is a flowchart for explaining a method for manufacturing a silicon carbide single crystal according to the present embodiment. FIG. 2 is a schematic cross-sectional view of the container 10 according to the present embodiment.

  As shown in FIG. 1, the method for manufacturing a silicon carbide single crystal according to the present embodiment includes a preparation step S1, an arrangement step S2, a heating step S3, and a silicon evaporation step S4.

(1.1) Preparatory process S1
In preparation step S1, silicon carbide single crystal material 20, carbon silicon supply material 40, and silicon material 60 are prepared.

  Silicon carbide single crystal material 20 has a flat surface 20a. Silicon carbide single crystal material 20 is made of silicon carbide single crystal. As the silicon carbide single crystal material 20, for example, 6H type silicon carbide single crystal (6H-SiC single crystal), 4H type silicon carbide single crystal (4H-SiC single crystal), 3C type silicon carbide single crystal (3C-SiC single crystal) ). The shape of the silicon carbide single crystal material 20 is, for example, a disk shape or a cylindrical shape.

  The carbon silicon supply material 40 has a flat surface 40a. Carbon silicon supply material 40 has a higher chemical potential than silicon carbide single crystal material 20. Carbon silicon supply material 40 is made of silicon carbide. Examples of the carbon silicon supply material 40 include 3C type silicon carbide polycrystal (3C—SiC polycrystal) or 4H type silicon carbide polycrystal (4H—SiC polycrystal), and a 3C type silicon carbide single crystal. (3C—SiC single crystal) or 4H type silicon carbide single crystal (4H—SiC single crystal). The carbon silicon supply material 40 is selected so that the chemical potential is higher than that of the silicon carbide single crystal material 20. The shape of the silicon carbide single crystal material 20 is, for example, a disk shape or a cylindrical shape.

  Carbon silicon supply material 40 supplies carbon and silicon to a silicon melt layer in which silicon material 60 is melted during the manufacture of a silicon carbide single crystal.

  Carbon silicon supply material 40 is preferably made of polycrystalline silicon carbide. Further, the molar ratio of silicon to carbon (Si / C) in the carbon silicon supply material 40 is preferably 1.00 or more. Also, the relative density of the carbon silicon feed material 40 is preferably greater than 95%. The relative density is a ratio of bulk density to theoretical density (bulk density / theoretical density).

  The silicon material 60 is made of silicon. Examples of the silicon material 60 include a silicon substrate (silicon substrate) or silicon powder. When the silicon material 60 is a silicon substrate, the shape of the silicon material 60 is, for example, a disk shape. The thickness of the silicon material 60 is preferably the same as the planar distance d described later.

  As shown in FIG. 2, the direction in which the silicon carbide single crystal grows is defined as a growth direction z. The growth direction z is a direction substantially perpendicular to the plane 20a and the plane 40a. A direction orthogonal to the growth direction z is defined as an orthogonal direction x.

  In the present embodiment, the silicon carbide single crystal material 20 has a disk shape with protrusions formed on the side surfaces. The protrusion is formed at the end of the growth direction z opposite to the plane 20a. The protrusion protrudes in the orthogonal direction x. The carbon silicon supply material 40 has a cylindrical shape with protrusions formed on the side surfaces. The protrusion is formed at the end opposite to the plane 40a in the growth direction z. The protrusion protrudes in the orthogonal direction x.

(1.2) Arrangement process S2
In the arranging step S2, the silicon carbide single crystal material 20, the carbon silicon supply material 40, and the silicon material 60 are arranged in the container 10.

  In the present embodiment, the container 10 includes a container body 15 and a lid body 17. The container body 15 has an opening. Through the opening, silicon carbide single crystal material 20, carbon silicon supply material 40, and silicon material 60 are arranged inside container 10. The container body 15 has a bottom portion 15a. The lid body 17 has a facing portion 17a facing the bottom portion 15a. A lid 17 is attached to the opening of the container body 15. The container 10 has heat resistance. An example of the container 10 is a graphite crucible.

  As shown in FIG. 2, in this embodiment, the container 10 is installed so that gravity g works from the lid body 17 toward the container body 15. Accordingly, the lid 17 side is the upper side, and the bottom 15a side of the container body 17 is the lower side.

  As shown in FIG. 2, holes corresponding to the shape of silicon carbide single crystal material 20 are formed in bottom portion 15 a. Silicon carbide single crystal material 20 is inserted into the hole so that flat surface 20a faces opposed portion 17a. That is, the end of silicon carbide single crystal material 20 on which the protrusion is formed is inserted into the hole. The inserted silicon carbide single crystal material 20 is rotated about the axis passing through the center of the silicon carbide single crystal material 20 and parallel to the growth direction z. Thereby, silicon carbide single crystal material 20 is fixed to container body 15.

  A hole corresponding to the shape of the carbon silicon supply material 40 is formed in the facing portion 17a. The carbon silicon supply material 40 is inserted into the hole so that the flat surface 40a faces the bottom 15a. That is, the end of the carbon silicon supply material 40 on which the protrusion is formed is inserted into the hole. The inserted carbon silicon supply material 40 is rotated about an axis passing through the center of the carbon silicon supply material 40 and parallel to the growth direction z. A carbon silicon supply material 40 is fixed to the lid body 17. Thereby, when the cover body 17 is attached to the container main body 15, the position of the carbon silicon supply material 40 is fixed. In the present embodiment, the carbon silicon supply material 40 is fixed to the lid body 17 with the lid body 17 removed from the container body 15.

  In the present embodiment, both the silicon carbide single crystal material 20 and the carbon silicon supply material 40 are fixed to the container 10.

  Silicon material 60 is arranged on flat surface 20a of fixed silicon carbide single crystal material 20. Therefore, silicon carbide single crystal material 20 is located below silicon material 60. After the silicon material 60 is disposed, the lid 17 is attached to the container body 15. Thereby, the carbon silicon supply material 40 is disposed on the upper side of the silicon material 60. Since the carbon silicon supply material 40 is fixed to the lid body 17, the position of the carbon silicon supply material 40 is fixed by attaching the lid body 17 to the container body 15.

  When the lid 17 is attached to the container body 15, the plane 40 a of the carbon silicon supply material 40 is in contact with the carbon silicon supply material 40. Thereby, silicon material 60 is sandwiched between flat surface 20a of silicon carbide single crystal material 20 and flat surface 40a of carbon silicon supply material 40. Therefore, silicon material 60 is interposed between silicon carbide single crystal material 20 and carbon silicon supply material 40.

  The position of the carbon silicon supply material 40 is fixed by attaching the lid 17 to the container body 15. Since silicon carbide single crystal material 20 and carbon silicon supply material 40 are fixed to container 10, in placement step S <b> 2, plane 20 a of silicon carbide single crystal material 20 and plane 40 a of carbon silicon supply material 40 are The plane distance d, which is the distance, is fixed.

  By adjusting the height in the growth direction z of the silicon carbide single crystal material 20 and the carbon silicon supply material 40, the planar distance d can be adjusted. In the present embodiment, the lid body 17 is attached to the container body 15 by screwing. For this reason, the plane distance d may be adjusted by adjusting the positions of the container body 15 and the lid body 17. The planar distance d is preferably in the range of 5 μm or more and 100 μm or less. If the planar distance d is 5 μm or more, even if silicon in the silicon molten layer reacts with carbon as the silicon carbide single crystal grows, the amount of silicon contained in the silicon molten layer can be sufficiently maintained. For this reason, the silicon carbide single crystal can be continuously grown. If the planar distance d is 100 μm or less, the carbon concentration gradient becomes steep, so that the carbon diffusion rate increases. Therefore, since the growth rate of the silicon carbide single crystal can be increased, a silicon carbide single crystal having a constant growth height can be stably produced within a predetermined time.

(1.3) Heating step S3
In the heating step S3, the container 10 is heated at a temperature not lower than the temperature at which the silicon material 60 melts and lower than the temperature at which the silicon material 60 boils.

  The container 10 in which the silicon carbide single crystal material 20, the carbon silicon supply material 40, and the silicon material 60 are arranged is heated using the heating member. As the heating member, for example, a heater or an induction heating coil can be used.

  The heating temperature may be a temperature at which the silicon material 60 is melted and a silicon melt layer is present. Therefore, for example, heating can be performed at a temperature of 1500 ° C. or higher and 2300 ° C. or lower. In order to produce a silicon carbide single crystal more stably, it is preferable to heat at a temperature of 1600 ° C. or higher and 2100 ° C. or lower. It is more preferable to heat at a temperature of 1700 degrees or more and 1900 degrees or less.

  The heating time can be appropriately set depending on the desired growth height. Since the silicon carbide single crystal grows when the heating time is longer, for example, it is preferable to heat for 200 hours or more.

  The silicon material 60 is melted by heating. For this reason, a silicon melt layer exists between the silicon carbide single crystal material 20 and the carbon silicon supply material 40. Since carbon silicon supply material 40 has a larger chemical potential than silicon carbide single crystal material 20, carbon contained in carbon silicon supply material 40 is dissolved in the silicon melt layer. The carbon dissolved in the silicon melt layer diffuses toward the silicon carbide single crystal material 20 having a low carbon concentration. Therefore, carbon on the carbon silicon supply material 40 side moves to the silicon carbide single crystal material 20 side, so that the carbon concentration on the silicon carbide single crystal material 20 side exceeds the solubility. As a result, the carbon on the silicon carbide single crystal material 20 side is deposited on the silicon carbide single crystal material 20 as a silicon carbide single crystal. By repeating the precipitation of the silicon carbide single crystal, the silicon carbide single crystal grows.

  In addition, not only the carbon contained in the carbon silicon supply material 40 but also silicon is dissolved in the silicon melt layer. Thus, silicon is supplied from the carbon silicon supply material 40 to the silicon melt layer.

The atmosphere inside the container 10 is an atmosphere that does not affect the growth of the silicon carbide single crystal. Therefore, the atmosphere inside the container 10 may be a vacuum of 10 ⁻⁴ Pa or less, or may be an inert gas atmosphere such as a rare gas.

(1.4) Silicon evaporation step S4
In the silicon evaporation step S4, the container 10 is heated at a temperature equal to or higher than the temperature heated in the heating step S3, and the silicon material 60 is evaporated.

  Since the evaporation occurs even if it is not higher than the boiling point, the heating temperature may not be higher than the boiling point of silicon. Therefore, for example, heating can be performed at a temperature of 2000 degrees or more and 2300 degrees or less. When the heating temperature is higher than the boiling point of silicon, the evaporation time of the silicon material 60 can be shortened.

  Since silicon carbide single crystal material 20 and carbon silicon supply material 40 are fixed to container 10, silicon carbide single crystal grown on silicon carbide single crystal material 20 by evaporation of silicon material 60, and carbon silicon supply A space is formed between the material 40.

  After the silicon material 60 is evaporated, the heating of the container 10 is stopped. Thereby, the temperature of the container 10 falls. After the temperature of the container 10 falls, the silicon carbide single crystal is taken out from the container 10. By the above, a silicon carbide single crystal can be manufactured.

(2) Function and effect As a result of intensive studies by the present inventors, it has been found that the thickness of the silicon melt layer changes and the growth rate changes depending on the weight of the material disposed on the upper side in the gravity direction of the silicon melt layer. It was. Therefore, the present inventor has completed the present invention based on the knowledge that the growth rate can be suppressed by suppressing the influence of the gravity of the material arranged on the upper side in the gravity direction of the silicon molten layer on the silicon molten layer. .

  According to the present embodiment, in the arranging step S2, the carbon silicon supply material 40 is arranged on the upper side of the silicon material 60, and the position of the carbon silicon supply material 40 is fixed. For this reason, even if the force which goes to the silicon molten layer side (namely, lower side) acts on the carbon silicon supply material 40 by gravity, the carbon silicon supply material 40 does not move to the silicon molten layer side. Therefore, even if the silicon material 60 is melted by the heating step S3 to form a silicon melt layer, the pressure applied from the carbon silicon supply material 40 to the silicon melt layer is suppressed. Therefore, it is possible to suppress the thickness of the silicon melt layer from being reduced due to the weight of the carbon silicon supply material 40.

  When the carbon silicon supply material 40 supplies carbon and silicon to the silicon melt layer, the weight of the carbon silicon supply material 40 is reduced. When the position of the carbon silicon supply material 40 is not fixed, the pressure applied from the carbon silicon supply material 40 to the silicon melt layer decreases. In this embodiment, since the position of the carbon silicon supply material 40 is fixed, a change in the thickness of the silicon molten layer due to the weight of the carbon silicon supply material can be suppressed.

  The thickness of the silicon molten layer depends on the growth rate of the silicon carbide single crystal. Since the change in the thickness of the silicon melt layer can be suppressed, the change in the growth rate of the silicon carbide single crystal can be suppressed. As a result, the silicon carbide single crystal can be manufactured more stably than in the past.

  In this embodiment, both the silicon carbide single crystal material 20 and the carbon silicon supply material 40 are fixed to the container 10. For this reason, it can control that adjusted plane distance d shifts. Thereby, the thickness of the silicon molten layer can be further controlled.

  Carbon silicon supply material 40 is preferably made of polycrystalline silicon carbide. Since silicon carbide polycrystal has a larger chemical potential than silicon carbide single crystal, the concentration gradient of carbon is steep. Thereby, since the growth rate of the silicon carbide single crystal can be increased, a silicon carbide single crystal having a constant growth height can be stably produced within a predetermined time.

  The molar ratio of silicon to carbon (Si / C) in the carbon silicon supply material 40 is preferably 1.00 or more. If the molar ratio of silicon to carbon (Si / C) is 1.00 or more, the amount of silicon contained in the carbon silicon supply material 40 is equal to or more than the amount of carbon. For this reason, sufficient silicon can be supplied to the silicon melt layer. Therefore, since the carbon reacts with silicon in the silicon melt layer to reduce the thickness of the silicon melt layer due to a decrease in the volume of the silicon melt layer, the silicon carbide single crystal is grown more stably than before. be able to.

  The relative density of the carbon silicon feed material 40 is preferably greater than 95%. If the relative density of the carbon silicon supply material 40 is too smaller than the relative density of the grown silicon carbide single crystal, the thickness of the silicon melt layer during growth tends to increase, and the growth rate becomes slow. The higher the relative density of the grown silicon carbide single crystal, the more desirable. Generally, the relative density of the grown silicon carbide single crystal is desirably 99% or more. For this reason, when the relative density of the grown silicon carbide single crystal is 99% or more, the growth rate tends to be slow when the relative density of the carbon silicon supply material 40 is less than 95%. When the relative density of the carbon silicon supply material 40 is larger than 95%, it is possible to suppress the growth rate from being slow. Furthermore, if the relative density of the carbon silicon feed material 40 is greater than 95%, the voids in the carbon silicon feed material 40 are reduced. For this reason, since carbon and silicon can be stably supplied from the carbon silicon supply material 40 to the silicon melt layer, changes in the growth rate of the silicon carbide single crystal can be suppressed. Therefore, the silicon carbide single crystal can be manufactured stably.

  When the temperature of the container 10 is lowered while the silicon molten layer is present, the liquid silicon molten layer changes into a solid silicon solid layer. Since the thermal expansion coefficient of silicon and the thermal expansion coefficient of silicon carbide single crystal are different, stress is generated at the interface between the grown silicon carbide single crystal and the silicon solid layer. As a result, the silicon carbide single crystal may be cracked.

  In the present embodiment, the container 10 is heated at a temperature equal to or higher than the temperature heated in the heating step S <b> 3, and the silicon molten layer that is the silicon material 60 is evaporated. By evaporating the silicon melt layer, since there is no silicon solid layer on the grown silicon carbide single crystal, there is no risk of cracking in the silicon carbide single crystal. As a result, a silicon carbide single crystal with good quality can be manufactured.

  Furthermore, since silicon carbide single crystal material 20 and carbon silicon supply material 40 are fixed to container 10, silicon carbide single crystal grown on silicon carbide single crystal material 20 by evaporation of silicon material 60, carbon A space is formed between the silicon supply material 40. For this reason, when removing the manufactured silicon carbide single crystal, there is no possibility of damaging the silicon carbide single crystal.

(3) Example 6H type silicon carbide single crystal (6H-SiC single crystal) was prepared as a silicon carbide single crystal material. A 3C silicon carbide polycrystal (3C-SiC polycrystal) having a molar ratio (Si / C) of 1.20 and a relative density of 98% was prepared as a carbon silicon supply material. A silicon substrate was prepared as a silicon material. A crucible using isotropic graphite was used for the container.

  Similar to the above-described embodiment, a 6H—SiC single crystal, a 3C—SiC polycrystal, and a silicon substrate were placed in a crucible (see FIG. 2). Specifically, a 6H—SiC single crystal was fixed to the bottom of the crucible. A silicon substrate was placed on the 6H—SiC single crystal. 3C-SiC polycrystal was fixed to the lid of the crucible. By attaching the crucible lid to the crucible, the 3C-SiC polycrystal was placed on the upper side of the silicon substrate and the position of the 3C-SiC polycrystal was fixed. A silicon substrate was interposed between the 6H—SiC single crystal and the 3C—SiC polycrystal. The plane distance between the plane of the 6H—SiC single crystal and the plane of the 3C—SiC polycrystal was adjusted so that the plane distance was 20 μm. The silicon substrate was in contact with the 6H—SiC single crystal and the 3C—SiC polycrystal.

  The crucible was heated at 1800 degrees for 1000 hours under an argon atmosphere. Next, the crucible was heated at 2000 degrees for 1 hour. Thereafter, the temperature of the crucible was cooled to room temperature. A silicon carbide single crystal was taken out from the crucible.

  Next, a new silicon carbide single crystal was manufactured under the same material and the same conditions. Specifically, a silicon carbide single crystal was manufactured with a plane distance of 20 μm.

  Both the growth heights of the obtained silicon carbide single crystals were 30 mm. Visual observation confirmed that both silicon carbide single crystals were not cracked. By fixing the position of the 3C—SiC polycrystal disposed on the upper side of the silicon material, the growth height could be made constant. That is, it was confirmed that the change in the growth rate of the silicon carbide single crystal can be suppressed and the silicon carbide single crystal can be manufactured stably.

(4) Other Embodiments Although the contents of the present invention have been disclosed through the embodiments of the present invention, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. The present invention includes various embodiments not described herein. Accordingly, the present invention includes various embodiments not described herein.

  Specifically, in the embodiment described above, the silicon carbide single crystal material 20 is disposed on the bottom portion 15a side of the container body 15 and the carbon silicon supply material 40 is disposed on the facing portion 17a side of the lid body 17. Not limited. The carbon silicon supply material 40 may be disposed on the bottom 15 a side of the container body 15, and the silicon carbide single crystal material 20 may be disposed on the facing portion 17 a side of the lid body 17. In this case, the silicon carbide single crystal grows toward the bottom portion 15a. At least the position of the silicon carbide single crystal material 20 is fixed. The position of the carbon silicon feed material 40 is also preferably fixed.

  Since the position of silicon carbide single crystal material 20 is fixed, the pressure applied from silicon carbide single crystal material 20 to the silicon molten layer is suppressed even when silicon material 60 is melted into a silicon molten layer by heating step S3. Is done. Therefore, it is possible to suppress a decrease in the thickness of the silicon melt layer due to the weight of silicon carbide single crystal material 20.

  As the silicon carbide single crystal grows on silicon carbide single crystal material 20, the weight of silicon carbide single crystal material 20 increases. When the position of silicon carbide single crystal material 20 is not fixed, the pressure applied from silicon carbide single crystal material 20 to the silicon molten layer increases. In the present embodiment, since at least the position of the silicon carbide single crystal material 20 is fixed, a change in the thickness of the silicon melt layer due to the weight of the silicon carbide single crystal material 20 can be suppressed. Therefore, a change in the growth rate of the silicon carbide single crystal can be suppressed. As a result, the silicon carbide single crystal can be manufactured more stably than in the past.

  In the embodiment described above, the silicon carbide single crystal material 20 is disposed in the container body 15 and the silicon material 60 is disposed, and then the carbon silicon supply material 40 is disposed. However, the present invention is not limited thereto. For example, silicon carbide single crystal material 20 and silicon material 60 may be disposed simultaneously. Other orders may be used.

  In the above-described embodiment, both the silicon carbide single crystal material 20 and the carbon silicon supply material 40 are fixed to the container 10, but the present invention is not necessarily limited thereto. One of silicon carbide single crystal material 20 and carbon silicon supply material 40 is fixed to container 10, and the other of silicon carbide single crystal material 20 and carbon silicon supply material 40 is arranged without being fixed to the bottom portion 15 a side of container 10. Also good. Specifically, for example, a disk-shaped silicon carbide single crystal material 20 is disposed on the bottom 15 a of the container 10. At this time, silicon carbide single crystal material 20 is arranged in container body 15 such that one main surface of silicon carbide single crystal material 20 is in contact with bottom portion 15a and flat surface 20a which is the other main surface opposes opposing portion 17a. To do. In this case, the silicon carbide single crystal material 20 is stable without being fixed to the container 10. The arrangement of the carbon silicon supply material 40 and the silicon material 60 is the same as in the above-described embodiment. Since the silicon carbide single crystal material 20 located on the bottom 15a side is stable without being fixed to the container 10, the plane 20a of the silicon carbide single crystal material 20 and the plane of the carbon silicon supply material 40 are disposed in the placement step S2. The plane distance d with 40a can be fixed.

  In the above-described embodiment, the silicon carbide single crystal material 20 and the carbon silicon supply material 40 are inserted and fixed in the holes formed in the container 10. However, the present invention is not limited to this.

  For example, a fixing member may be attached to the container 10 to fix the silicon carbide single crystal material 20 and the carbon silicon supply material 40 to the container 10. The fixing member is attached to the bottom portion 15 a of the container body 15, the side surface, and / or the facing portion 17 a of the lid body 17. The silicon carbide single crystal material 20 or the like may be fixed to the container 10 by holding the silicon carbide single crystal material 20 or the like by the fixing member. An example of the fixing member is a clamp. In addition, the silicon carbide single crystal material 20 or the like may be fixed to the container 10 by bolts. Note that the hole for inserting the bolt is preferably formed at a position that does not affect the growth of the silicon carbide single crystal.

  The method described above is a method of mechanically fixing, but a method of chemically fixing may be used. Specifically, the silicon carbide single crystal material 20 or the like may be fixed to the container 10 with an adhesive. For example, the columnar carbon silicon supply material 40 may be fixed to the facing portion 17 a of the lid body 17 using a phenol resin adhesive. An adhesive is applied to the surface opposite to the flat surface 40 a, and the surface opposite to the flat surface 40 a is bonded to the facing portion 17 a of the lid body 17. Thereby, silicon carbide single crystal material 20 etc. are fixed to container 10.

  In addition, for example, silicon carbide single crystal material 20 and carbon silicon supply material 40 may be fixed by a connecting member that connects silicon carbide single crystal material 20 and carbon silicon supply material 40. For example, the connecting member may have a shape that has a longitudinal direction and is bent at both ends in the longitudinal direction. Specifically, what has what is called a bowl shape or a U-shape is mentioned as a connection member. One end of the connecting member is fixed to the side surface of silicon carbide single crystal material 20, and the other end of the connecting member is fixed to the side surface of carbon silicon supply material 40. Thereby, the position of silicon carbide single crystal material 20 or carbon silicon supply material 40 arranged on the upper side of silicon material 60 can be fixed. In addition, it is preferable to form the position which fixes the edge part of a connection member in the position which does not affect the growth of a silicon carbide single crystal.

  Further, in the above-described embodiment, the container 10 is installed so that the gravity g works from the lid body 17 toward the container body 15, but is not limited thereto. For example, the container 10 may be installed so that gravity g works from the container body 15 toward the lid body 17. In this case, it is preferable that at least one of silicon carbide single crystal material 20 and carbon silicon supply material 40 disposed on silicon material 60 is fixed to container 10. That is, it is preferable that the material disposed on the container body 15 side than the silicon material 60 is fixed to the container 10.

  It should be noted that the above-described embodiment and other embodiments can be appropriately combined as long as the effects of the present invention are not impaired.

  As described above, the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  DESCRIPTION OF SYMBOLS 10 ... Container, 15 ... Container main body, 15a ... Bottom part, 17 ... Cover, 17a ... Opposite part, 20 ... Silicon carbide single crystal material, 20a ... Plane (of silicon carbide single crystal material), 40 ... Carbon silicon supply material, 40a ... (carbon silicon supply material) plane 60 ... silicon material

Claims (6)

A silicon carbide single crystal material comprising a silicon carbide single crystal;
A carbon silicon supply material having a larger chemical potential than the silicon carbide single crystal material and made of silicon carbide;
A preparation step of preparing a silicon material made of silicon;
An arrangement step of arranging the silicon carbide single crystal material, the carbon silicon supply material and the silicon material in a container;
A heating step of heating the container at a temperature equal to or higher than a temperature at which the silicon material melts and lower than a temperature at which the silicon material boils, and
A method for producing a silicon carbide single crystal using a metastable solvent epitaxy method for growing a silicon carbide single crystal on a surface of the silicon carbide single crystal material,
In the arrangement step,
Any one material of the silicon carbide single crystal material or the carbon silicon supply material is disposed on the upper side of the silicon material,
Fixing the position of said one material,
A method for producing a silicon carbide single crystal, wherein the silicon material is interposed between the silicon carbide single crystal material and the carbon silicon supply material. In the arrangement step,
Fixing the one material to the container;
The silicon carbide single crystal production according to claim 1, wherein the silicon carbide single crystal material or the other material different from the one material of the carbon silicon supply material is disposed closer to the bottom of the container than the one material. Method.   The method for producing a silicon carbide single crystal according to claim 1, wherein the carbon silicon supply material is made of polycrystalline silicon carbide.   The method for producing a silicon carbide single crystal according to any one of claims 1 to 3, wherein a molar ratio of silicon to carbon in the carbon silicon supply material is 1.00 or more.   The method for producing a silicon carbide single crystal according to any one of claims 1 to 4, wherein a relative density of the carbon silicon supply material is greater than 95%.   The method for producing a silicon carbide single crystal according to any one of claims 1 to 5, further comprising a silicon evaporation step in which the container is heated at a temperature equal to or higher than the temperature heated in the heating step to evaporate the silicon material.

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