Combined crucible and oxide crystal growth method

Abstract

The invention provides a combined crucible and an oxide crystal growth method.The combined crucible is used for oxide crystal growth and comprises a first ceramic crucible, a second ceramic crucible, a third ceramic crucible and a fourth ceramic crucible, the graphite layer is arranged in the first ceramic crucible; the second ceramic crucible comprises a second containing space with the top open and the bottom closed, and the second ceramic crucible is arranged in the graphite layer. The combined crucible is designed by adopting an iridium-free scheme, so that the cost of the crucible can be greatly reduced.

Description

Technical Field

[0001] The invention relates to oxide crystal growth, and in particular to a combined crucible and an oxide crystal growth method. Background Art

[0002] The development of the semiconductor industry is closely related to the iteration and update of semiconductor materials, from the first generation of semiconductor materials germanium and silicon, to the second generation of semiconductor materials gallium arsenide and indium phosphide, to the third generation of semiconductor materials such as silicon carbide, gallium nitride, boron nitride, etc., and oxide semiconductor materials such as gallium oxide, tin oxide, zinc oxide, etc. The iteration and update of semiconductor materials make the performance of semiconductor devices better and the size of semiconductor devices smaller.

[0003] Among oxide semiconductor materials, gallium oxide is an ultra-wide bandgap semiconductor material. For the growth of gallium oxide crystals, the main melt methods currently used are the Czochralski method, the guided mold method, and other melt methods to prepare large-sized, high-quality single crystals. These methods for preparing gallium oxide single crystals all use iridium crucibles. Tin oxide is another wide bandgap semiconductor material. Only a few institutions have conducted research on the growth of tin oxide crystals. For example, the Leibniz Institute for Crystal Growth in Germany reported the research progress on the growth of tin oxide crystals in a public document in 2013, which pointed out that the most suitable growth method for tin oxide crystals is the physical vapor transport (PVT) method, and the crucible used is also an iridium crucible. However, since iridium is extremely expensive, exceeding 1,000 yuan per gram, and the weight of a single iridium crucible generally used for oxide crystal growth is 5 to 10 kg, the cost of just one crucible is several million, which will lead to a significant increase in the growth cost of oxide crystals, which is not conducive to the industrialization of oxide crystals.

[0004] In addition, whether it is gallium oxide or tin oxide, the raw materials are directly placed in the iridium crucible and in direct contact with the iridium crucible. Under high temperature conditions, a small amount of gallium oxide will decompose to produce low-valent gallium oxide or even elemental gallium. Tin oxide will decompose to produce stannous oxide and oxygen under high temperature conditions. These products will not only corrode the inner surface of the iridium crucible in contact with them to varying degrees, causing the loss of precious metal iridium; but also affect the quality of the crystal.

[0005] Reference Figure 1, the patent application number 202111069487.5 discloses a method for growing gallium oxide crystals and a combined crucible for growing gallium oxide crystals. The combined crucible disclosed in the patent is composed of an iridium crucible 10 located on the outer layer and a ceramic crucible 20 located on the inner layer, and the gallium oxide raw material is contained in the ceramic crucible 20. The outer iridium crucible 10 is heated by medium-frequency induction to increase its temperature, and then the iridium crucible 10 transfers the heat to the inner ceramic crucible 20, and the ceramic crucible 20 heats the gallium oxide raw material to form a melt. This avoids direct contact between the gallium oxide raw material and the iridium crucible 10, avoids its corrosion loss to iridium, and also avoids the mixing of iridium metal on the quality of the crystal. However, this method still uses an iridium crucible, and the problem of using a large number of expensive iridium crucibles for industrial production still exists.

[0006] The patent application number 202120958933.7 discloses a tungsten-molybdenum crucible for growing oxide crystals by the guided-mode method. The applicant has tried to install the tungsten crucible in the central area of ​​the thermal field in the furnace chamber of the crystal growth furnace, and heated the tungsten crucible by medium-frequency induction. The heating results show that after the tungsten crucible rises to a certain temperature (about 1500°C), it is impossible to maintain temperature stability in this temperature range, and the temperature will quickly drop by several hundred degrees. After comprehensively evaluating and analyzing the medium-frequency power supply, thermal field and other conditions of the equipment, the applicant preliminarily inferred that the reason for this situation is that the resistivity of tungsten is a positive temperature coefficient, and its resistivity gradually increases with increasing temperature, which affects the compatibility with the output power of the medium-frequency induction power supply, resulting in the inability of the tungsten crucible to maintain temperature at high temperatures, and thus unable to meet the temperature zone requirements of gallium oxide crystal growth (>1800°C).

[0007] In addition, in the field of silicon carbide crystal growth, medium frequency induction is used to heat the graphite crucible, and then the physical vapor transport (PVT) method is used to grow silicon carbide crystals. In order to realize the iridium-free method for preparing oxide crystals, on the basis of patent application number 202111069487.5, the applicant has tried to use graphite crucibles instead of iridium crucibles to grow oxide crystals. The heating results show that under appropriate output power, the temperature of the graphite crucible can be heated to >2000°C by medium frequency induction, and can be maintained stable for a long time, which meets the temperature zone requirements for oxide crystal growth. However, since the oxide crystals will decompose and produce an oxygen atmosphere during their growth, the graphite crucible will be oxidized, which will directly affect the heating effect, and then affect the quality and performance of the grown oxide crystals.

[0008] It should be noted that the above information disclosed in the background technology section is only intended to deepen the understanding of the overall background technology of this application, and should not be regarded as admitting or suggesting in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0009] In view of this, a technical problem to be solved by the present invention is to provide a combined crucible and an oxide crystal growth method, which can at least to some extent solve the deficiencies of the above-mentioned prior art problems.

[0010] As a first aspect of the present invention, the technical solution of the embodiment of the combined crucible provided is as follows:

[0011] A combined crucible for growing oxide crystals, comprising:

[0012] A first ceramic crucible comprising a first accommodating space;

[0013] A graphite layer is disposed inside the first ceramic crucible;

[0014] The second ceramic crucible comprises a second accommodating space with an open top and a closed bottom, and is arranged inside the graphite layer.

[0015] Furthermore, an anti-oxidation coating is provided on the surface of the graphite layer.

[0016] Preferably, the graphite layer is a graphite ring with an opening at the top and an opening at the bottom; or the graphite layer is a graphite crucible with an opening at the top and a closed bottom.

[0017] Preferably, the material of the first ceramic crucible is zirconium oxide, boron nitride or pyrolytic boron nitride; and / or the material of the second ceramic crucible is zirconium oxide, boron nitride or pyrolytic boron nitride.

[0018] Furthermore, the combined crucible also includes a shielding structure component for isolating the graphite layer from the protective gas during the growth of the oxide crystals.

[0019] Preferably, the material of the shielding structure component is zirconium oxide, boron nitride or pyrolytic boron nitride.

[0020] Preferably, the shielding structure assembly is arranged on the top of the first ceramic crucible and the second ceramic crucible, and the shielding structure assembly, the first ceramic crucible and the second ceramic crucible seal the graphite layer.

[0021] Preferably, the shielding structure assembly is arranged on the surface of the graphite layer to wrap the graphite layer.

[0022] Preferably, the first ceramic crucible has an opening at the top and a completely closed bottom; or the first ceramic crucible has an opening at the top and a through hole is provided at the bottom so as to be not completely closed.

[0023] As a second aspect of the present invention, the technical solution of an embodiment of the oxide crystal growth method provided is as follows:

[0024] A method for growing an oxide crystal, wherein the oxide is gallium oxide, wherein the method for growing an oxide crystal comprises the following steps:

[0025] Installing a composite crucible filled with gallium oxide raw materials in a furnace chamber of a crystal growth furnace, wherein the composite crucible is the composite crucible described in any one of the first aspects above;

[0026] Evacuating the original gas in the furnace chamber and filling it with protective gas;

[0027] The combined crucible is heated by electromagnetic induction heating to raise the temperature of the gallium oxide raw material, the gallium oxide is heated and melted, and the gallium oxide crystal is grown by a melt method.

[0028] A method for growing an oxide crystal, wherein the oxide is tin oxide, wherein the method for growing an oxide crystal comprises the following steps:

[0029] Installing a composite crucible filled with tin oxide raw material in a furnace chamber of a crystal growth furnace, wherein the composite crucible is the composite crucible described in any one of the first aspects above;

[0030] Evacuating the original gas in the furnace chamber and filling it with protective gas;

[0031] The combined crucible is heated by electromagnetic induction heating to raise the temperature of the tin oxide raw material, the tin oxide is heated and sublimated, and the tin oxide crystals are grown by physical vapor transport.

[0032] The combined crucible of the present invention adopts an iridium-free design, and at least includes a first ceramic crucible located in the outer layer, a second ceramic crucible located in the inner layer, and a graphite layer disposed between the two. The graphite layer is heated by electromagnetic induction heating, and then the heat is transferred to the second ceramic crucible in the inner layer to increase its temperature. The second ceramic crucible heats the oxide raw material contained therein to increase its temperature, thereby performing crystal growth. Its beneficial effects are as follows:

[0033] (1) The crucible is designed without iridium, which directly avoids the use of iridium crucibles, can greatly reduce the manufacturing cost of gallium oxide crystals or tin oxide crystals, and is very beneficial to the industrial application of oxide crystals;

[0034] (2) The oxide raw material is contained in the second ceramic crucible of the inner layer, which avoids direct contact between the gallium oxide or tin oxide raw material and the iridium gold, thereby avoiding the corrosion loss of the oxide raw material to the precious metal iridium gold under high temperature environment, and also avoiding the influence of the loss of precious metal on the quality of the oxide crystal;

[0035] (3) The anti-oxidation protection design of the graphite layer in the combined crucible, or the combined crucible also includes a shielding structure component design that isolates the graphite layer from the external gas, can eliminate the oxidation risk of the graphite layer, thereby eliminating the thermal field fluctuation in the furnace chamber caused by the oxidation of the graphite layer, and further eliminating the impact on the quality of the oxide crystals caused by this. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a cross-sectional view of an existing combined crucible;

[0037] Figure 2 is a cross-sectional view of a first embodiment of a combined crucible according to an embodiment of the present invention;

[0038] Figure 3 is a cross-sectional view of a second embodiment of the combined crucible involved in an embodiment of the present invention;

[0039] Figure 4 is a cross-sectional view of a third embodiment of a combined crucible according to an embodiment of the present invention;

[0040] Figure 5 is a cross-sectional view of a fourth embodiment of a combined crucible according to an embodiment of the present invention;

[0041] Figure 6 is a cross-sectional view of a fifth embodiment of a combined crucible according to an embodiment of the present invention;

[0042] The technical features corresponding to the marks in the accompanying drawings are:

[0043] 10 Iridium Crucible

[0044] 20 Ceramic Crucible

[0045] 30 Ceramic Ring Assembly

[0046] 31 First Ceramic Crucible

[0047] 32. Second Ceramic Crucible

[0048] 41 graphite crucible

[0049] 42 graphite ring

[0050] 50 filling layers

[0051] 60 Anti-oxidation coating DETAILED DESCRIPTION

[0052] In order to more clearly illustrate the technical solution of the present invention, the following will be briefly introduced through embodiments or prior art descriptions. Obviously, the following drawings are only illustrations of some embodiments of the present invention, and the protection scope required by the present invention is not limited to the embodiments. For ordinary technicians in this field, other drawings can also be obtained based on these drawings without creative work.

[0053] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0054] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0056] In the present invention, unless otherwise specified, the directional words used, such as "up, down, left, right", etc., are usually relative to the directions shown in the drawings, or are relative to the vertical, perpendicular or gravity directions of the components themselves; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0057] First embodiment

[0058] This embodiment provides a combined crucible for growing oxide crystals. Figure 2 is a cross-sectional view of a first embodiment of a combined crucible according to an embodiment of the present invention, Figure 3 is a cross-sectional view of a second embodiment of a combined crucible according to an embodiment of the present invention, Figure 4 is a cross-sectional view of a third embodiment of a combined crucible according to an embodiment of the present invention, Figure 5 is a cross-sectional view of a fourth embodiment of a combined crucible according to an embodiment of the present invention, Figure 6 is a cross-sectional view of a fifth embodiment of the combined crucible involved in the embodiment of the present invention, see Figures 2 to 6 , wherein the combined crucible comprises:

[0059] The first ceramic crucible 31 includes a first accommodating space;

[0060] A graphite layer is disposed inside the first ceramic crucible 31;

[0061] The second ceramic crucible 32 includes a second accommodating space with an open top and a closed bottom, and is disposed inside the graphite layer.

[0062] The combined crucible of this embodiment adopts an iridium-free design, and at least includes a first ceramic crucible located in the outer layer, a second ceramic crucible located in the inner layer, and a graphite layer arranged between the two. The graphite layer is heated and heated by electromagnetic induction heating, and then the heat is transferred to the second ceramic crucible in the inner layer to increase its temperature. The second ceramic crucible heats and heats the oxide raw material contained therein, thereby growing crystals. Its beneficial effects are: (1) The crucible is designed without iridium, which directly avoids the use of iridium crucibles, can greatly reduce the manufacturing cost of gallium oxide crystals or tin oxide crystals, and is very beneficial to the industrial application of oxide crystals; (2) The oxide raw material is contained in the second ceramic crucible in the inner layer, which avoids direct contact between the gallium oxide or tin oxide raw material and iridium, thereby avoiding the corrosion loss of the oxide raw material to the precious metal iridium in a high temperature environment, and also avoiding the influence of the loss of precious metal on the quality of oxide crystals.

[0063] Furthermore, the surface of the graphite layer is provided with an anti-oxidation coating, such as Figure 5 The 60% on the surface of the graphite layer is an anti-oxidation coating, which can eliminate the oxidation risk of the graphite layer, thereby eliminating the thermal field fluctuation in the furnace chamber caused by the oxidation of the graphite layer, and further eliminating the impact on the quality of the oxide crystals caused by the oxidation. The materials of the anti-oxidation coating include but are not limited to zirconium oxide coating, boron nitride coating, and pyrolytic boron nitride coating.

[0064] Preferably, the graphite layer is a graphite ring 42 with an opening at the top and an opening at the bottom, such as Figure 3 , Figure 4 and Figure 5 or the graphite layer is a graphite crucible 41 with an open top and a closed bottom, such as Figure 2 described.

[0065] Preferably, the material of the first ceramic crucible is zirconium oxide, boron nitride or pyrolytic boron nitride; and / or the material of the second ceramic crucible is zirconium oxide, boron nitride crucible or pyrolytic boron nitride. The material of the first ceramic crucible located in the outer layer and the second ceramic crucible located in the inner layer may be the same or different. The technicians in this field can choose according to the actual needs, and the present invention does not limit it; the thickness of the first ceramic crucible located in the outer layer and the second ceramic crucible located in the inner layer may be the same or different. Preferably, the thickness of the second ceramic crucible located in the inner layer is relatively thinner to facilitate the inward conduction of heat. The thickness of the second ceramic crucible located in the inner layer cannot be too thin. Too thinness will cause the strength of the second ceramic crucible to deteriorate when resistant to high-temperature thermal shock, and it is easy to crack. Therefore, it is recommended that the wall thickness of the second ceramic crucible be in the range of 2mm to 6mm.

[0066] Furthermore, there is a first distance between the first ceramic crucible and the graphite layer, and the ceramic crucible and the graphite layer will undergo a certain degree of thermal expansion at high temperature. The first distance is set between the first ceramic crucible and the graphite layer to reserve expansion space to avoid the stress caused by thermal expansion mismatch, which may cause the graphite layer or the ceramic crucible to crack, thereby affecting the service life of the crucible; and / or there is a second distance between the second ceramic crucible and the graphite layer, and the ceramic crucible and the graphite layer will undergo a certain degree of thermal expansion at high temperature. The second distance is set between the second ceramic crucible and the graphite layer to reserve expansion space to avoid the stress caused by thermal expansion mismatch, which may cause the graphite layer or the ceramic crucible to crack, thereby affecting the service life of the crucible.

[0067] Furthermore, the combined crucible also includes a shielding structure component for isolating the graphite layer from the protective gas during the growth of the oxide crystal, thereby eliminating the risk of oxidation of the graphite layer, thereby eliminating the thermal field fluctuations in the furnace chamber caused by the oxidation of the graphite layer, and further eliminating the resulting impact on the quality of the oxide crystal.

[0068] Preferably, the material of the shielding structure component is zirconium oxide, boron nitride or pyrolytic boron nitride.

[0069] Preferably, the shielding structure assembly is arranged on the top of the first ceramic crucible and the second ceramic crucible, and the shielding structure assembly, the first ceramic crucible and the second ceramic crucible seal the graphite layer. Figure 2 and Figure 3 The ceramic ring assembly 30 in the figure is a shielding structure assembly. The ceramic ring assembly 30 covers the top of the first ceramic crucible and the second ceramic crucible 2. The ceramic ring assembly 30, the first ceramic crucible and the second ceramic crucible surround the graphite crucible 41 to isolate it from the external atmosphere. The ceramic ring assembly 30 can be designed with a boss or without a boss. Figure 2In the embodiment, the ceramic ring assembly 30 is designed with a boss, so that the ceramic ring assembly 30 can be prevented from sliding left and right and affecting the surrounding effect of the graphite crucible. Figure 2 In the combined crucible shown, a high temperature resistant adhesive can be added between the ceramic ring assembly 30 and the first ceramic crucible 31 and the second ceramic crucible 32 to better seal the graphite crucible, strengthen the isolation effect between the graphite crucible and the external atmosphere, and better prevent the graphite crucible from being oxidized.

[0070] Preferably, the shielding structure assembly is arranged on the surface of the graphite layer to wrap the graphite layer. Figure 4 and Figure 5 The filler layer 50 is a shielding structure component. The filler layer 50 is located between the first ceramic crucible 31 and the second ceramic crucible 32, and wraps the graphite ring 42. The filler layer 50, the first ceramic crucible 31 and the ceramic crucible 32 surround the graphite ring 42 to isolate it from the external atmosphere. The material of the filler layer 50 includes but is not limited to zirconium oxide, boron nitride, pyrolytic boron nitride, and aluminum oxide.

[0071] Preferably, the first ceramic crucible 31 has an open top and a completely closed bottom. Figures 1 to 5 As shown; or the first ceramic crucible 31 is open at the top and has a through hole at the bottom so that it is not completely closed. Figure 6 As shown, a through hole is opened at the bottom center position of the first ceramic crucible 31, and a through hole is also opened at the bottom center position of the graphite crucible 41. The reason is that in the actual oxide crystal growth process, the oxide raw material is contained in the second ceramic crucible 32. Through the bottom opening design of the first ceramic crucible 31 and the graphite crucible 41, infrared temperature measurement can directly measure the temperature of the bottom of the second ceramic crucible 32. In this way, the temperature monitoring of the oxide raw material contained in the second ceramic crucible 32 is relatively more direct, and the temperature monitoring during the crystal growth process is more accurate, which is more beneficial to the growth of oxide crystals.

[0072] Second embodiment

[0073] This embodiment provides a method for growing oxide crystals:

[0074] (1) When the oxide is gallium oxide, the oxide crystal growth method comprises the following steps:

[0075] S1, installing a composite crucible containing gallium oxide raw materials in a furnace chamber of a crystal growth furnace, wherein the composite crucible is any composite crucible of the first embodiment, specifically, for example, Figure 2The combined crucible of the structure, the material of the first ceramic crucible 31 located in the outer layer is zirconia, the material of the second ceramic crucible 32 located in the inner layer is zirconia, and the material of the ceramic ring assembly 30 is zirconia; the wall thickness of the second ceramic crucible 32 is 3mm; the combined crucible is installed in the central area of ​​the thermal field in the gallium oxide crystal growth furnace chamber;

[0076] S2, evacuate the original gas in the furnace cavity and fill it with protective gas. Specifically, for example, the furnace cavity can be sealed, and a mechanical pump can be used to evacuate the furnace cavity to reduce the vacuum degree to 1×10 -3 Pa, then carbon dioxide is filled in as protective gas to maintain the pressure in the furnace chamber between 0.8 and 1 atmosphere;

[0077] S3, using electromagnetic induction heating to heat the combined crucible to heat the gallium oxide raw material, the gallium oxide is heated and melted, and the gallium oxide crystals are grown using the melt method. Specifically, the water cooling circulation device can be turned on, and the medium frequency power supply can be turned on, and the combined crucible is heated by electromagnetic induction. The first ceramic crucible 31 transfers heat to the second ceramic crucible 32 in the inner layer through the graphite crucible 41, and the gallium oxide raw material contained in the inner second ceramic crucible is heated through the second ceramic crucible in the inner layer to melt the gallium oxide raw material to form a gallium oxide melt, and the crystals are grown using the melt method.

[0078] (2) When the oxide is tin oxide, the oxide crystal growth method comprises the following steps:

[0079] S1, installing a composite crucible containing tin oxide raw materials in a furnace chamber of a crystal growth furnace, wherein the composite crucible is any composite crucible of the first embodiment, specifically, for example, Figure 2 The combined crucible of the structure, the material of the first ceramic crucible 31 located in the outer layer is zirconia, the material of the second ceramic crucible 32 located in the inner layer is zirconia, and the material of the ceramic ring assembly 30 is zirconia; the wall thickness of the second ceramic crucible 32 is 3mm; the combined crucible is installed in the central area of ​​the thermal field in the gallium oxide crystal growth furnace chamber;

[0080] S2, evacuating the original gas in the furnace chamber and filling it with protective gas. Specifically, for example, the furnace chamber can be sealed, and a mechanical pump is used to evacuate the furnace chamber until the vacuum degree in the furnace chamber drops to ≤10Pa, and then carbon dioxide is filled in as protective gas to maintain the pressure in the furnace chamber between 0.8 and 1 atmosphere;

[0081] S3, using electromagnetic induction heating to heat the combined crucible to heat the tin oxide raw material, the tin oxide is heated and sublimated, and the tin oxide crystals are grown by physical vapor transport. Specifically, the water cooling circulation device can be turned on, and the medium frequency power supply can be turned on, and the combined crucible is heated by electromagnetic induction. The first ceramic crucible 31 transfers heat to the inner second ceramic crucible 32 through the graphite crucible 41, and the gallium oxide raw material contained in the inner second ceramic crucible is heated through the inner second ceramic crucible to sublimate and decompose the tin oxide raw material to form a gaseous intermediate product, and the physical vapor transport (PVT) method is used to grow tin oxide crystals.

[0082] In the above-mentioned process of growing gallium oxide and tin oxide crystals, since the combined crucible of the first embodiment is adopted, the combined crucible solution is directly designed without iridium, which directly avoids the use of iridium crucibles, greatly reduces the manufacturing cost of gallium oxide crystals, and is very beneficial to the industrial application of gallium oxide crystals.

[0083] It should be understood that the above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A combined crucible for growing oxide crystals. Its special feature is that include: A first ceramic crucible comprising a first accommodating space; A graphite layer is disposed inside the first ceramic crucible; The second ceramic crucible comprises a second accommodating space with an open top and a closed bottom, and is arranged inside the graphite layer.

2. The combined crucible according to claim 1, Features: The surface of the graphite layer is provided with an anti-oxidation coating.

3. The combined crucible according to claim 1, Features: The graphite layer is a graphite ring with an opening at the top and an opening at the bottom; or the graphite layer is a graphite crucible with an opening at the top and a closed bottom.

4. The combined crucible according to claim 1, Features: The material of the first ceramic crucible is zirconium oxide, boron nitride or pyrolytic boron nitride; and / or the material of the second ceramic crucible is zirconium oxide, boron nitride or pyrolytic boron nitride.

5. The combined crucible according to claim 1, Features: The composite crucible further comprises a shielding structure assembly for isolating the graphite layer from the protective gas during the growth of the oxide crystal.

6. The combined crucible according to claim 5, Features: The material of the shielding structure component is zirconium oxide, boron nitride or pyrolytic boron nitride.

7. The combined crucible according to any one of claims 5 to 6, Features: The shielding structure assembly is arranged on the top of the first ceramic crucible and the second ceramic crucible, and the shielding structure assembly, the first ceramic crucible and the second ceramic crucible seal the graphite layer.

8. The combined crucible according to any one of claims 5 to 6, Features: The shielding structure component is arranged on the surface of the graphite layer to wrap the graphite layer.

9. The combined crucible according to claim 1, It is characterized in that The first ceramic crucible has an opening at the top and a completely closed bottom; or the first ceramic crucible has an opening at the top and a through hole at the bottom so as to be not completely closed.

10. A method for growing an oxide crystal, wherein the oxide is gallium oxide. It is characterized in that The oxide crystal growth method comprises the following steps: Installing a composite crucible containing gallium oxide raw materials in a furnace chamber of a crystal growth furnace, wherein the composite crucible is the composite crucible according to any one of claims 1 to 9; Evacuating the original gas in the furnace chamber and filling it with protective gas; The combined crucible is heated by electromagnetic induction heating to raise the temperature of the gallium oxide raw material, the gallium oxide is heated and melted, and the gallium oxide crystal is grown by a melt method.

11. A method for growing oxide crystals, wherein the oxide is tin oxide, It is characterized in that The oxide crystal growth method comprises the following steps: Installing a composite crucible filled with tin oxide raw material in a furnace chamber of a crystal growth furnace, wherein the composite crucible is the composite crucible according to any one of claims 1 to 9; Evacuating the original gas in the furnace chamber and filling it with protective gas; The combined crucible is heated by electromagnetic induction heating to raise the temperature of the tin oxide raw material, the tin oxide is heated and sublimated, and the tin oxide crystals are grown by physical vapor transport.

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