阅读说明：本技术 SiC单晶生长用坩埚、SiC单晶的制造方法及SiC单晶制造装置 (Crucible for growing SiC single crystal, method for producing SiC single crystal, and SiC single crystal production apparatus ) 是由 藤川阳平 于 2020-01-08 设计创作，主要内容包括：本发明涉及SiC单晶生长用坩埚和使用了该SiC单晶生长用坩埚的SiC单晶的制造方法及SiC单晶制造装置。本发明的SiC单晶生长用坩埚具备容纳SiC原料的原料容纳部和支承在所述原料容纳部的上方配置的晶种的晶种支承部,所述原料容纳部具有内面朝向下方逐渐变细的缩窄部。(The present invention relates to a crucible for SiC single crystal growth, and a method and an apparatus for producing SiC single crystal using the same. The crucible for SiC single crystal growth of the present invention includes a raw material container for containing a SiC raw material and a seed crystal support portion for supporting a seed crystal disposed above the raw material container, and the raw material container has a narrowed portion whose inner surface is tapered downward.)

1. A crucible for SiC single crystal growth, comprising:

a raw material accommodating portion for accommodating a SiC raw material; and

a seed crystal support portion for supporting a seed crystal disposed above the raw material accommodating portion,

the raw material containing portion has a narrowed portion whose inner surface is tapered downward.

2. The crucible for SiC single crystal growth according to claim 1,

the narrowed portion of the raw material containing portion is continuously tapered.

3. The crucible for SiC single crystal growth according to claim 1 or 2,

the narrowed portion of the raw material containing portion is linearly tapered.

4. The crucible for SiC single crystal growth according to any one of claims 1 to 3,

the outer surface of the narrowed portion of the raw material containing portion is tapered.

5. A method for producing a SiC single crystal using the crucible for SiC single crystal growth according to any one of claims 1 to 4, the method comprising:

filling the raw material containing portion of the crucible for SiC single crystal growth with an SiC raw material; and

and heating the raw material container so that a heating center is located within the range of the narrowed portion of the raw material container.

6. An apparatus for producing a SiC single crystal, comprising a crucible for SiC single crystal growth and a heater for heating the crucible for SiC single crystal growth,

the crucible for SiC single crystal growth according to any one of claims 1 to 4,

the heater is disposed so that a heating center is located within the range of the narrowed portion of the raw material containing portion.

Technical Field

The present invention relates to a crucible for SiC single crystal growth, and a method and an apparatus for producing SiC single crystal using the same.

Background

Silicon carbide (SiC) has an order of magnitude larger insulation breakdown field and 3 times larger band gap than silicon (Si). SiC has characteristics such as high thermal conductivity about 3 times higher than Si. Therefore, SiC is expected to be applied to power devices, high-frequency devices, high-temperature operation devices, and the like.

As one of the methods for producing SiC single crystal, sublimation method is well known. The sublimation method is as follows: in a cylindrical crucible, a SiC raw material is heated to a high temperature to generate a sublimation gas, and the sublimation gas is recrystallized on a seed crystal composed of a relatively low-temperature SiC single crystal to grow the SiC single crystal. In the production of SiC single crystals using this sublimation method, the SiC single crystals are required to grow with a large diameter and/or a long length, and the size of the crucible is required to be increased.

In the sublimation method, the crucible is generally heated from the outside. Therefore, the inside of the crucible tends to have a temperature distribution in which the wall side is at a high temperature and the center portion is at a low temperature. In the interior of the crucible having such a temperature distribution, the sublimation gas generated in the vicinity of the wall side of the crucible is cooled in the central portion of the crucible to precipitate SiC, and the SiC raw material may not be effectively used. In particular, in a large crucible, the temperature difference between the wall side and the central portion tends to increase, and therefore SiC is likely to precipitate in the central portion. Further, SiC deposited in the crucible is different from the original state of the SiC raw material, and cannot be reused as the SiC raw material in such a state. Therefore, a crucible capable of suppressing deposition of SiC inside the crucible and effectively utilizing SiC raw material is desired.

In order to sublimate the SiC raw material uniformly and stably inside the crucible, patent document 1 describes a crucible for SiC single crystal growth in which a heat conductor is provided at the center of the bottom inside the crucible.

Disclosure of Invention

Problems to be solved by the invention

However, since the heat conductor is provided inside the crucible for SiC single crystal growth described in patent document 1, the amount of SiC raw material that can be contained inside the crucible is small, and it is difficult to increase the amount of SiC single crystal growth. That is, in the crucible for SiC single crystal growth described in patent document 1, it is difficult to produce a large-diameter and/or long-sized SiC single crystal.

The present invention has been made in view of the above problems, and an object thereof is to provide a crucible for SiC single crystal growth in which precipitation of SiC in the crucible is not likely to occur even in a large size that enables production of a large-diameter and/or long-size grown SiC single crystal, and SiC raw material can be effectively used, and a method for producing a SiC single crystal and an apparatus for producing a SiC single crystal using the crucible for SiC single crystal growth.

Means for solving the problems

As a result of intensive studies, the inventors of the present application have found that, by providing a raw material containing portion of a crucible containing SiC raw material with a narrowed portion whose inner surface is tapered downward and heating the raw material containing portion so that the heating center is within the range of the narrowed portion, even if the raw material containing portion is set to a large size that enables production of a large-diameter and/or long-size grown SiC single crystal, the temperature of the central portion of the SiC raw material filled in the raw material containing portion can be increased, whereby precipitation of SiC at the central portion of the raw material containing portion is less likely to occur, and SiC raw material can be effectively used.

That is, the present invention adopts the following means to solve the above problems.

(1) A crucible for SiC single crystal growth according to one aspect of the present invention includes: a raw material accommodating portion for accommodating a SiC raw material; and a seed crystal support portion for supporting a seed crystal disposed above the raw material accommodating portion, wherein the raw material accommodating portion has a narrowed portion whose inner surface is tapered downward.

(2) The crucible for SiC single crystal growth according to item (1) above may be configured such that the narrowed portion of the raw material container is continuously tapered.

(3) In the crucible for SiC single crystal growth according to the above (1) or (2), the narrowed portion of the raw material container may be configured to be linearly tapered.

(4) The crucible for SiC single crystal growth according to any one of (1) to (3) above, wherein an outer surface of the narrowed portion of the raw material container is tapered.

(5) A method for producing a SiC single crystal according to another aspect of the present invention is a method for producing a SiC single crystal using the crucible for SiC single crystal growth according to the above aspect, the method including: filling the raw material containing portion of the crucible for SiC single crystal growth with an SiC raw material; and heating the raw material container so that a heating center is located within the range of the narrowed portion of the raw material container.

(6) An apparatus for producing a SiC single crystal according to another aspect of the present invention includes: a crucible for SiC single crystal growth according to the above aspect, and a heater for heating the crucible for SiC single crystal growth, the heater being disposed such that a heating center is located within the range of the narrowed portion of the raw material containing portion.

Effects of the invention

According to the present invention, it is possible to provide a crucible for SiC single crystal growth in which precipitation of SiC in the crucible is not likely to occur even in a large size that enables production of a large-diameter and/or long-size SiC single crystal, and SiC raw material can be effectively used, and a method for producing a SiC single crystal and an apparatus for producing a SiC single crystal using the same.

Drawings

Fig. 1 is a schematic sectional view showing a conventional SiC single crystal growth crucible.

FIG. 2 is a schematic sectional view showing an example of a crucible for SiC single crystal growth according to an embodiment of the present invention.

FIG. 3 is a partially enlarged schematic sectional view showing an example of an apparatus for producing an SiC single crystal using the crucible for SiC single crystal growth of FIG. 2.

FIG. 4 is a schematic sectional view showing another example of a crucible for SiC single crystal growth according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view showing another example of a crucible for SiC single crystal growth according to an embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view showing another example of a crucible for SiC single crystal growth according to an embodiment of the present invention.

Fig. 7 is a schematic sectional view showing a crystal growth apparatus used in the simulation of example 1.

Fig. 8 is a graph showing the results of the simulation of examples 1 to 5 and comparative example 1.

Fig. 9 is a schematic sectional view showing a crystal growth apparatus used in the simulation of example 6.

Fig. 10 is a graph showing the results of the simulation of example 6.

Description of the reference symbols

1 SiC raw Material

2 seed crystal

10. Crucible for SiC single crystal growth of 10a, 10b, 10c, 10e

20. 20a, 20b, 20c, 20e raw material containing parts

21b, 21c, 21e body

22b, 22c, 22e are narrowed

23c flat part

24d, 24e support member

25e thermal conductor

30 cover part

31 seed crystal support part

40. 41, 42 SiC Single Crystal manufacturing apparatus

50 heating apparatus

51 high-frequency coil

52 heater

60 insulating material

Detailed Description

Hereinafter, the crucible for SiC single crystal growth, the method for producing SiC single crystal, and the apparatus for producing SiC single crystal according to the present embodiment will be described in detail with reference to the drawings as appropriate.

In the drawings used in the following description, a characteristic portion may be shown in an enlarged manner for convenience, and the dimensional ratio of each component may be different from the actual one. The materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited to these examples, and can be implemented by being appropriately modified within the scope not changing the gist thereof.

(conventional crucible for SiC Single Crystal growth)

Fig. 1 is a schematic sectional view showing a conventional SiC single crystal growth crucible.

As shown in fig. 1, the crucible 10a for SiC single crystal growth includes a raw material container 20a that contains the SiC raw material 1, and a lid portion 30 disposed above the raw material container 20 a. The raw material container 20a is a bottomed cylindrical body. The lid portion 30 has a seed crystal support portion 31 that supports the seed crystal 2.

In the sublimation method, the SiC raw material 1 is heated to a high temperature in the crucible 10a for SiC single crystal growth to generate sublimation gas, and the sublimation gas is recrystallized on the seed crystal 2 at a relatively low temperature to grow the seed crystal 2. The SiC raw material 1 is generally heated by heating the SiC single crystal growth crucible 10a from the outside. Therefore, the inside of the crucible 10a for SiC single crystal growth tends to have a temperature distribution in which the vicinity of the wall of the raw material containing portion 20a is high in temperature and the central portion is low in temperature. In the crucible 10a for SiC single crystal growth having such a temperature distribution, the sublimation gas generated in the vicinity of the wall side of the raw material container 20a is cooled in the central portion of the raw material container 20a, and SiC is precipitated, and the SiC raw material 1 may not be effectively used.

(crucible for SiC Single Crystal growth of the present embodiment)

FIG. 2 is a schematic sectional view showing an example of a crucible for SiC single crystal growth according to an embodiment of the present invention.

The crucible 10b for SiC single crystal growth of the present embodiment shown in fig. 2 is different from the above-described conventional crucible 10a for SiC single crystal growth in that the raw material container 20b has a main body portion 21b and a narrowed portion 22b whose inner surface is tapered downward. Note that, the same reference numerals are given to the portions common to the crucible 10b for SiC single crystal growth of the present embodiment and the conventional crucible 10a for SiC single crystal growth, and the description thereof is omitted.

In the crucible 10b for SiC single crystal growth of the present embodiment, the main body portion 21b of the raw material containing portion 20b is cylindrical. However, the shape of the body portion 21b is not limited to a cylindrical shape. The body 21b may be square.

The narrowed portion 22b of the raw material container 20b is a cone shape that continuously and linearly tapers. However, the shape of the narrowed portion 22b is not limited to a conical shape. The narrowed portion 22b may be tapered in a stepwise manner, or may be curved inward or outward of the material accommodating portion 20 b. For example, the narrowing portion 22b may have a truncated cone shape or a hemispherical shape. In addition, the inner and outer surfaces of the narrowed portion 22b are tapered, but only the inner surface may be tapered. Further, a support portion for standing the SiC single crystal growth crucible 10b on its own may be provided at the constricted portion 22 b. The support portion may be integrally connected to the narrowed portion 22b, or may be detachable.

As the material of the raw material container 20b and the lid 30, for example, a known heat-resistant material, such as graphite or tantalum carbide, which is used as a material of a crucible for SiC single crystal growth, can be used.

(SiC Single Crystal manufacturing apparatus)

Fig. 3 is a partially enlarged schematic cross-sectional view showing an example of an apparatus for producing a SiC single crystal according to an embodiment of the present invention.

The SiC single crystal manufacturing apparatus 40 shown in fig. 3 includes a crucible 10 for SiC single crystal growth and a heater 50. The crucible 10 for SiC single crystal growth is a crucible 10b for SiC single crystal growth shown in fig. 2. Further, the arrows in fig. 3 indicate the flow of heat. The density of the SiC material 1 indicates a temperature distribution, and the temperature is high in a light portion and low in a dense portion.

The heater 50 is disposed so that the heating center H is located within the range of the narrowed portion 22b of the raw material holding portion 20b, the heating center means a portion at which the temperature of the outer surface of the raw material holding portion 20b of the crucible 10 for SiC single crystal growth is the highest when heated by the heater 50, that is, a portion at which the heat transferred from the heater 50 to the outer surface of the raw material holding portion 20b is the most, in the case where the heater 50 is a coil-type induction heater, the heating center is generally a portion in contact with the center of the coil portion of the coil-type induction heater, in the case where the heater 50 is a resistance heater, the heating center is generally a portion closest to the resistance heater, by locating the heating center H within the range of the narrowed portion 22b, that is, by setting the narrowing start position L at which the narrowed portion 22b starts to be 0mm or more upward with respect to the heating center H, the heat is easily transferred to the entire narrowed portion 22b, and therefore, the SiC raw material 1 is uniformly heated until the bottom portion side of the narrowed portion 22b is excessively long, and the SiC raw material holding portion 20b is preferably, the SiC raw material holding portion 20b is more likely to be heated by the height 6360 mm or less, and the heated by the narrowed portion 20b, and the c is preferably, and the distance is less.

The amount of filling of SiC material 1 into material container 20b is preferably such that the height of constriction start position L of constriction 22b relative to heating center H is within ± 20% of the filling height of SiC material 1, the filling height of SiC material 1 is the height of SiC material 1 on the central axis of material container 20b, and by setting the amount of filling of SiC material 1 within the above range, it is possible to create a temperature environment for soaking until the central portion of the material without excessively reducing the amount of filling of material.

As the heater 50, a known heater used as a heater for an SiC single crystal manufacturing apparatus, such as a resistance heater or an induction heater, can be used. When an induction heater is used, the periphery of the SiC single crystal growth crucible 10 is preferably covered with a heat insulating material. The heat insulating material is not particularly limited, and a known heat insulating material such as a carbon fiber felt that is used as a material for a SiC single crystal production apparatus can be used.

(method for producing SiC Single Crystal)

A method for producing an SiC single crystal according to an embodiment of the present invention is a method for producing an SiC single crystal using the crucible 10b for SiC single crystal growth according to the present embodiment described above, and includes a filling step of filling the raw material container 20b with the SiC raw material 1 and a heating step of heating the raw material container 20b so that the heating center is located within the range of the narrowed portion 22b of the raw material container 20 b.

In the crucible 10b for SiC single crystal growth according to the present embodiment having the above-described configuration, the raw material container 20b filled with the SiC raw material 1 is provided with the narrowed portion 22b whose inner surface is tapered downward, and the raw material container 20b is heated so that the heating center H is within the range of the narrowed portion 22b, whereby the temperature of the central portion of the SiC raw material 1 filled in the raw material container 20b can be increased and the uniformity of the temperature distribution can be improved even when the size is large enough to produce a large-diameter and/or long-size SiC single crystal. Thus, according to the crucible 10b for SiC single crystal growth of the present embodiment, deposition of SiC is less likely to occur in the central portion of the raw material container 20b, and the SiC raw material 1 can be effectively used.

In the SiC single crystal manufacturing apparatus 40 using the SiC single crystal growth crucible 10b of the present embodiment, the heater 50 is disposed so that the heating center H is located within the range of the narrowed portion 22b of the raw material containing portion 20 b. Therefore, in the production of SiC single crystal, the temperature of the central portion of the SiC raw material 1 filled in the raw material container 20b can be increased, and the uniformity of the temperature distribution can be improved.

In the method for producing SiC single crystal using the crucible 10b for SiC single crystal growth according to the present embodiment, the raw material container 20b is heated so that the heating center H is located within the range of the narrowed portion 22b of the raw material container 20 b. Therefore, the temperature of the central portion of the SiC raw material 1 filled in the raw material container 20b can be increased, and the uniformity of the temperature distribution can be improved.

(modification example)

FIG. 4 is a schematic sectional view showing another example of a crucible for SiC single crystal growth according to an embodiment of the present invention.

The crucible 10c for SiC single crystal growth of the present embodiment shown in fig. 4 is different from the crucible 10b for SiC single crystal growth of the present embodiment described above in that the raw material container 20c has the main body portion 21c and the narrowed portion 22c, and the narrowed portion 22c has a truncated conical shape in that the bottom portion of the narrowed portion 22c is the flat portion 23 c. Note that, the same reference numerals are given to the portions common to the crucible 10c for SiC single crystal growth of the present embodiment and the crucible 10b for SiC single crystal growth of the present embodiment, and the description thereof is omitted.

The crucible 10c for SiC single crystal growth can stand by itself because the bottom of the narrowed portion 22c is the flat portion 23 c. Thus, the crucible 10c for SiC single crystal growth can be installed in the SiC single crystal production apparatus without using a support member.

FIG. 5 is a schematic cross-sectional view showing another example of a crucible for SiC single crystal growth according to an embodiment of the present invention.

The crucible 10d for SiC single crystal growth shown in fig. 5 is different from the crucible 10b for SiC single crystal growth of the present embodiment described above in that the raw material container 20d has the main body portion 21d and the constricted portion 22d, and the constricted portion 22d is supported by the support member 24 d. Note that, the same reference numerals are given to the portions common to the crucible 10c for SiC single crystal growth of the present embodiment and the crucible 10b for SiC single crystal growth of the present embodiment, and the description thereof is omitted.

The support member 24d is a bottomed cylindrical body having an opening at the upper portion. A recess is formed in the center of the bottom of the support member 24d, and the tip of the narrowed portion 22d of the SiC single crystal growth crucible 10d is inserted into the recess. As a material of the support member 24d, for example, a heat-resistant material such as graphite, tantalum carbide, SiC, or the like can be used. By using the support member 24d, the stability when the crucible 10c for SiC single crystal growth is set in the SiC single crystal production apparatus can be made higher.

FIG. 6 is a schematic cross-sectional view showing another example of a crucible for SiC single crystal growth according to an embodiment of the present invention.

The crucible 10e for SiC single crystal growth shown in fig. 6 is different from the crucible 10b for SiC single crystal growth of the present embodiment described above in that the raw material container 20e has the main body portion 21e and the constricted portion 22e, and the constricted portion 22e is supported by the support member 24e filled with the heat conductor 25 e. Note that, the same reference numerals are given to the portions common to the crucible 10e for SiC single crystal growth of the present embodiment and the crucible 10b for SiC single crystal growth of the present embodiment, and the description thereof is omitted.

The support member 24e is a bottomed cylindrical body having an opening portion filled with a heat conductor 25 e. The heat conductor 25e is filled in contact with the outer surface of the narrowed portion 22e of the SiC single crystal growth crucible 10 e. As the material of the support member 24e and the heat conductor 25e, for example, a heat-resistant material such as graphite, tantalum carbide, or SiC can be used. By filling the support member 24e with the thermal conductor 25e, the strength of the support member 24e is improved. Therefore, the stability of the crucible 10e for SiC single crystal growth when installed in the SiC single crystal production apparatus is further improved. The heat conductor 25e may be in direct contact with the SiC raw material 1.

While the embodiments of the present invention have been described in detail, the present invention is not limited to the specific embodiments, and various modifications and/or changes can be made within the scope of the present invention described in the claims.