Flux for beta-gallium oxide crystal growth and crystal growth method based on flux

Abstract

The invention provides a fluxing agent for beta-gallium oxide crystal growth and a crystal growth method based on the fluxing agent, and belongs to the technical field of crystal growth. The fluxing agent for beta-gallium oxide crystal growth comprises at least two of an antimony-containing compound, a cesium-containing compound and a boron-containing compound. The fluxing agent system provided by the invention does not contain toxic and harmful components such as lead oxide, lead fluoride and the like which are commonly used in high-temperature fluxing agents. By utilizing the fluxing agent system, the growth temperature interval of the gallium oxide crystal is 750-1050 DEG C. Compared with the existing fluxing agent system, the growth temperature of the crystal is effectively reduced, the solvent viscosity is small, the volatilization of components is less, the high-temperature solution is clear and transparent, the growth process of the crystal is convenient to control in real time, and the obtained crystal is relatively good in quality and free of a wrapping phenomenon; and the high-quality beta-Ga2O3 crystal is easy to obtain.

Description

Technical Field

[0001] This invention relates to the field of crystal growth technology, and in particular to a flux for growing β-gallium oxide crystals and a crystal growth method based on the flux. Background Technology

[0002] β-Ga₂O₃ single crystal is a transparent conductive oxide with a bandgap of 4.8 eV and a high transducer field strength of 8 MV / cm, exhibiting high breakdown voltage performance, making it highly suitable for optoelectronic devices and high-voltage devices. However, gallium oxide single crystals have a high melting point (approximately 1820℃), making them prone to decomposition and volatilization during high-temperature growth. This leads to instability during growth, making temperature control difficult and easily generating numerous oxygen vacancies, resulting in defects such as twins, voids, and dislocations. Furthermore, the excessively high growth temperature poses a significant challenge to the performance control of the crucible material and the β-Ga₂O₃ crystal. Since the 1960s, flux-assisted growth of β-Ga₂O₃ crystals has been proposed. This method effectively lowers the growth temperature of β-Ga₂O₃ crystals (generally below 1600℃). However, the flux method requires toxic and harmful components such as PbO and PbF₂, and the grown crystals often exhibit macroscopic defects such as inclusions and clouding, limiting the usable portion of the crystal. To avoid toxic and harmful components such as PbO and PbF2, researchers have found that molybdate and Bi-containing fluxes can effectively lower the gallium oxide growth temperature and solve the gallium oxide volatilization problem. However, the minimum growth temperature of this flux system (900-950℃) is still too high. Higher growth temperatures lead to easier volatilization and decomposition of the flux and gallium oxide, increasing the likelihood of defects during growth and hindering the growth of high-quality β-Ga2O3 crystals. Furthermore, prolonged growth at this temperature affects the lifespan of the resistance furnace; a temperature of 800-850℃ is generally optimal for resistance furnaces. This temperature is also close to the softening temperature of platinum crucibles (1000℃), and prolonged use can cause severe deformation of the platinum crucible, which is detrimental to crystal growth. Additionally, Bi-containing compounds can corrode the platinum crucible, affecting its lifespan. Therefore, further optimization of the gallium oxide flux system is needed to lower the gallium oxide growth temperature (optimal temperature around 800℃) and prevent the flux from reacting with the growth crucible (platinum), thus achieving more stable gallium oxide crystal growth. Summary of the Invention

[0003] In view of this, the present invention aims to provide a flux for the growth of β-gallium oxide crystals and a crystal growth method based on the flux.

[0004] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of the present invention is a flux for the growth of β-gallium oxide crystals, comprising at least two of antimony-containing compounds, cesium-containing compounds, and boron-containing compounds.

[0005] The second technical solution of the present invention is a method for growing β-gallium oxide crystals, which uses the above-mentioned flux to grow β-gallium oxide crystals.

[0006] Furthermore, this includes the following steps: Gallium oxide single-phase polycrystalline powder and flux are mixed and heated to melt, resulting in a mixed melt. The saturation point temperature of the mixed melt is determined, and a gallium oxide seed crystal is introduced into the mixed melt at a temperature higher than the saturation point temperature. The temperature is kept constant, and then cooled to the saturation point temperature. After cooling, the crystal is grown to obtain a β-gallium oxide crystal.

[0007] The present invention discloses the following technical effects: The flux system proposed in this invention does not contain toxic or harmful components such as lead oxide and lead fluoride commonly used in high-temperature fluxes.

[0008] Using the flux system of the present invention, the growth temperature range of gallium oxide crystal is 750-1050℃. Compared with the existing flux system, the growth temperature of the crystal is effectively reduced. The solvent viscosity is low, the component volatilization is low, the high temperature solution is clear and transparent, which makes it easy to control the crystal growth process in real time. The obtained crystal has better quality, no encapsulation phenomenon, and it is easy to obtain high-quality β-Ga2O3 crystals. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 The image shows the XRD diffraction pattern of the gallium oxide crystal obtained in Example 1 of this invention. Detailed Implementation

[0011] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0012] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included within the scope of this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0013] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0014] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0015] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0016] The first aspect of the present invention provides a flux for the growth of β-gallium oxide crystals, comprising at least two of antimony-containing compounds, cesium-containing compounds, and boron-containing compounds.

[0017] In a preferred embodiment of the present invention, the antimony-containing compound is Sb2O3, the cesium-containing compound is Cs2CO3, CsF or CsCl, and the boron-containing compound is B2O3 or H2BO3.

[0018] In a preferred embodiment of the present invention, when the flux is an antimony-containing compound and a cesium-containing compound, the molar ratio of the antimony-containing compound and the cesium-containing compound is (3-10):(1-4). When the flux is an antimony-containing compound and a boron-containing compound, the molar ratio of the antimony-containing compound to the boron-containing compound is (2-16):(2-4). When the flux is a cesium-containing compound and a boron-containing compound, the molar ratio of the cesium-containing compound to the boron-containing compound is (1-4):(2-8); When the flux is an antimony-containing compound, a cesium-containing compound, and a boron-containing compound, the molar ratio of the antimony-containing compound, the cesium-containing compound, and the boron-containing compound is (2-14):(1-2):(1-7).

[0019] More preferably, when the flux is an antimony-containing compound and a cesium-containing compound, the molar ratio of the antimony-containing compound and the cesium-containing compound is 3:1, 3:2, 3:4, 4:1, 4:3, 5:2, 5:4, 6:1, 6:3, 6:4, 7:2, 7:4, 8:1, 8:3, 9:1, 9:2, 10:1, 10:2 or 10:3.

[0020] More preferably, when the flux is an antimony-containing compound and a boron-containing compound, the molar ratio of the antimony-containing compound to the boron-containing compound is 3:2, 3:4, 4:3, 5:2, 5:3, 5:4, 6:4, 7:2, 7:3, 7:4, 8:2, 8:3, 8:4, 9:2, 9:3, 9:4, 10:2, 10:3, 11:1, 11:3, 11:4, 12:2, 12:3, 13:1, 13:2, 13:4, 14:2, 14:3, 15:1, 15:2, 15:4, 16:1, or 16:3.

[0021] More preferably, when the flux is a cesium-containing compound and a boron-containing compound, the molar ratio of the cesium-containing compound and the boron-containing compound is 1:2, 2:3, 2:5, 2:7, 3:2, 3:5, 3:8, 4:2, 4:3, 4:5, or 4:7.

[0022] More preferably, when the flux is an antimony-containing compound, a cesium-containing compound, and a boron-containing compound, the molar ratio of the antimony-containing compound, the cesium-containing compound, and the boron-containing compound is 14:2:1, 14:2:3, 14:2:5, 14:2:7, 11:2:1, 11:2:3, 11:2:5, 11:2:7, 9:2:1, 9:2:3, 9:2:5, 9:2:7, 7:1:1, 7:1:3, 7:1:5, 7:1:7, 5:2:1, 5:2:3, 5:2:6, or 5:2:7.

[0023] A second aspect of the present invention provides a method for growing β-gallium oxide crystals, using the above-mentioned flux for growing β-gallium oxide crystals.

[0024] Specifically, the method for growing β-gallium oxide crystal includes the following steps: Gallium oxide single-phase polycrystalline powder and flux are mixed and heated to melt, resulting in a mixed melt. The saturation point temperature of the mixed melt is determined, and a gallium oxide seed crystal is introduced into the mixed melt at a temperature higher than the saturation point temperature. The temperature is kept constant, and then cooled to the saturation point temperature. After cooling, the crystal is grown to obtain a β-gallium oxide crystal.

[0025] In a preferred embodiment of the present invention, the molar ratio of the gallium oxide crystal single-phase polycrystalline powder to the flux is (1-3):(3-20).

[0026] More preferably, the molar ratio of the gallium oxide single-phase polycrystalline powder and the flux is 1:3, 1:5, 1:7, 1:9, 1:11, 1:13, 1:15, 1:17, 1:20, 2:3, 2:5, 2:7, 2:9, 2:11, 2:13, 2:17, 2:19, 3:5, 3:9, 3:13, 3:16, 3:17, or 3:19.

[0027] In a preferred embodiment of the present invention, the heating and melting parameters are set as follows: heating to 800-1100°C at a heating rate of 1-30°C / h, and holding at that temperature for 5-80 hours.

[0028] More preferably, the heating and melting parameters are set as follows: heating to 800-1100℃ at a heating rate of 20-30℃ / h, and holding at that temperature for 15-25 hours.

[0029] In a preferred embodiment of the present invention, the saturation point temperature is 750-1050℃. The method for determining the saturation point temperature is a conventional technique used by those skilled in the art, and is not the focus of patent protection for this invention; therefore, it will not be elaborated upon here.

[0030] In a preferred embodiment of the present invention, the method for preparing the gallium oxide seed crystal is as follows: after cooling the above-mentioned mild melt to the saturation point temperature, it is then slowly cooled to room temperature at a rate of 0.5-10℃ / h, and gallium oxide seed crystals are obtained by spontaneous crystallization.

[0031] In a preferred embodiment of the present invention, before introducing the gallium oxide seed crystal into the mixed melt, the step of preheating the gallium oxide seed crystal is further included; the preheating time is 5-60 minutes.

[0032] In a preferred embodiment of the present invention, the temperature is maintained for 5-60 minutes.

[0033] In a preferred embodiment of the present invention, the cooling rate when cooling to the saturation point temperature is 1-60℃ / h.

[0034] More preferably, the cooling rate when cooling to the saturation point temperature is 5℃ / h, 10℃ / h, 15℃ / h, 20℃ / h, 30℃ / h, 40℃ / h, 50℃ / h or 60℃ / h.

[0035] In a preferred embodiment of the present invention, the cooling growth is as follows: starting from the saturation point temperature, the temperature is reduced at a rate of 0.1 to 5°C / day while rotating the crystal to induce nucleation on the seed crystal for crystal growth. After the crystal grows to the required size, the crystal is removed from the liquid surface and then cooled to room temperature at a rate of 1-80°C / h (more preferably, 5°C / h, 8°C / h, 10°C / h, 20°C / h, 30°C / h, 40°C / h, 50°C / h, 60°C / h, 70°C / h or 80°C / h) to obtain a β-gallium oxide crystal.

[0036] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0037] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0038] Example 1 (1) The compound gallium oxide crystal single-phase polycrystalline powder and the flux Sb2O3-B2O3 were mixed in a molar ratio of Ga2O3:Sb2O3-B2O3=1:15, wherein the molar ratio of Sb2O3 to B2O3 was 10:3. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 900℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 15 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 775℃, then slowly cool it to room temperature at a rate of 0.5℃ / h to obtain gallium oxide seed crystals through spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixed melt for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixed melt. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 775℃ at a cooling rate of 30℃ / h. Then, the temperature is lowered at a rate of 2℃ / day, and the seed crystal rod is rotated at a speed of 10 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and cooled to room temperature at a rate of 8℃ / hour. A gallium oxide crystal with a size of 15mm×10mm×2mm and good crystallinity can be obtained. The XRD diffraction pattern of the (100) plane is as follows. Figure 1 As shown, there are no extraneous peaks.

[0039] Comparative Example 1 Gallium oxide single-phase polycrystalline powder and flux Sb2O3-B2O3 were mixed in a molar ratio of Ga2O3:Sb2O3-B2O3=1:25, wherein the molar ratio of Sb2O3 to B2O3 was 10:3. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 900℃ at a heating rate of 30℃ / h. The mixture was held at the temperature for 15 hours to obtain a mixed melt. The mixed melt was cooled to 750°C, and then slowly cooled to room temperature at a rate of 0.5°C / h. Spontaneous crystallization did not yield gallium oxide crystals, but instead produced a mixture of GaBO3, GaSbO4, etc.

[0040] Example 2 (1) The compound gallium oxide single-phase polycrystalline powder and the flux Cs2CO3-Sb2O3 were mixed in a molar ratio of Ga2O3:Cs2CO3-Sb2O3=1:20, wherein the molar ratio of Cs2CO3 to Sb2O3 was 3:8. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 1050℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 15 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 885℃, then slowly cool it to room temperature at a rate of 0.5℃ / h to obtain gallium oxide seed crystals through spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixed melt for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixed melt. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 885℃ at a cooling rate of 20℃ / h. The temperature is then reduced at a rate of 0.2℃ / day, and the seed crystal rod is rotated at a speed of 10 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is reduced to room temperature at a rate of 10℃ / hour to obtain a gallium oxide crystal with a size of 5mm×3mm×2mm.

[0041] Example 3 (1) The compound gallium oxide crystal single-phase polycrystalline powder and the flux Sb2O3-Cs2CO3-B2O3 were mixed in a molar ratio of Ga2O3:Sb2O3-Cs2CO3-B2O3=1:3, wherein the molar ratio of Sb2O3, Cs2CO3 and B2O3 was 5:2:7. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 1020℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 25 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 905℃, then slowly cool it to room temperature at a rate of 3.5℃ / h, and obtain gallium oxide seed crystals by spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixed melt for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixed melt. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 905℃ at a cooling rate of 40℃ / h. The temperature is then lowered at a rate of 2.5℃ / day, and the seed crystal rod is rotated at a speed of 30 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is lowered to room temperature at a rate of 40℃ / hour to obtain a gallium oxide crystal with a size of 8mm×5mm×2mm.

[0042] Example 4 (1) The compound gallium oxide single-phase polycrystalline powder and the flux Cs2CO3-B2O3 were mixed in a molar ratio of Ga2O3:Cs2CO3-B2O3=2:15, wherein the molar ratio of Cs2CO3 to B2O3 was 3:5. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 980℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 25 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 935°C. Then, slowly cool it to room temperature at a rate of 25°C / h to obtain gallium oxide seed crystals through spontaneous crystallization. (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixed melt for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixed melt. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 935℃ at a cooling rate of 35℃ / h. The temperature is then lowered at a rate of 2.5℃ / day, and the seed crystal rod is rotated at a speed of 30 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is lowered to room temperature at a rate of 40℃ / hour to obtain a gallium oxide crystal with a size of 8mm×5mm×2mm.

[0043] Example 5 (1) The compound gallium oxide single-phase polycrystalline powder and the flux Sb2O3-B2O3 were mixed in a molar ratio of Ga2O3:Sb2O3-B2O3=2:17, wherein the molar ratio of Sb2O3 to B2O3 was 16:3. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 1000℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 15 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 930℃, then slowly cool it to room temperature at a rate of 0.5℃ / h to obtain gallium oxide seed crystals through spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixed melt for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixed melt. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 930℃ at a cooling rate of 55℃ / h. The temperature is then lowered at a rate of 2℃ / day, and the seed crystal rod is rotated at a speed of 10 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is lowered to room temperature at a rate of 8℃ / hour to obtain a gallium oxide crystal with a size of 15mm×10mm×2mm.

[0044] Example 6 (1) The compound gallium oxide crystal single-phase polycrystalline powder and the flux Sb2O3-B2O3 were mixed in a molar ratio of Ga2O3:Sb2O3-B2O3=3:10, wherein the molar ratio of Sb2O3 to B2O3 was 7:2. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 1000℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 15 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 925℃, then slowly cool it to room temperature at a rate of 0.5℃ / h to obtain gallium oxide seed crystals through spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixed melt for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixed melt. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 925℃ at a cooling rate of 40℃ / h. The temperature is then lowered at a rate of 2℃ / day, and the seed crystal rod is rotated at a speed of 10 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is lowered to room temperature at a rate of 8℃ / hour to obtain a gallium oxide crystal with a size of 15mm×10mm×2mm.

[0045] Example 7 (1) The compound gallium oxide single-phase polycrystalline powder and the flux Cs2CO3-Sb2O3 were mixed in a molar ratio of Ga2O3:Cs2CO3-Sb2O3=1:15, wherein the molar ratio of Cs2CO3 to Sb2O3 was 3:10. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 1050℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 15 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 955℃, then slowly cool it to room temperature at a rate of 0.5℃ / h to obtain gallium oxide seed crystals through spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixed melt for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixed melt. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 955℃ at a cooling rate of 30℃ / h. The temperature is then reduced at a rate of 0.2℃ / day, and the seed crystal rod is rotated at a speed of 10 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is reduced to room temperature at a rate of 10℃ / hour to obtain a gallium oxide crystal with a size of 5mm×3mm×2mm.

[0046] Example 8 (1) The compound gallium oxide single-phase polycrystalline powder and the flux Cs2CO3-Sb2O3 were mixed in a molar ratio of Ga2O3:Cs2CO3-Sb2O3=2:9, wherein the molar ratio of Cs2CO3 to Sb2O3 was 2:5. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 1100℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 15 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 1020℃, then slowly cool it to room temperature at a rate of 0.5℃ / h to obtain gallium oxide seed crystals through spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixture for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixed melt. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 1020℃ at a cooling rate of 25℃ / h. The temperature is then reduced at a rate of 0.2℃ / day, and the seed crystal rod is rotated at a speed of 10 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is reduced to room temperature at a rate of 10℃ / hour to obtain a gallium oxide crystal with a size of 5mm×3mm×2mm.

[0047] Example 9 (1) The compound gallium oxide single-phase polycrystalline powder and the flux Sb2O3-Cs2CO3-B2O3 were mixed in a molar ratio of Ga2O3:Sb2O3-Cs2CO3-B2O3=2:13, wherein the molar ratio of Sb2O3, Cs2CO3 and B2O3 was 14:2:7. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 1060℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 25 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 990℃, then slowly cool it to room temperature at a rate of 3.5℃ / h to obtain gallium oxide seed crystals through spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixture for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixture. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 990℃ at a cooling rate of 35℃ / h. The temperature is then lowered at a rate of 2.5℃ / day, and the seed crystal rod is rotated at a speed of 30 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is lowered to room temperature at a rate of 40℃ / hour to obtain a gallium oxide crystal with a size of 8mm×5mm×2mm.

[0048] Example 10 (1) The compound gallium oxide single-phase polycrystalline powder and the flux Sb2O3-Cs2CO3-B2O3 were mixed in a molar ratio of Ga2O3:Sb2O3-Cs2CO3-B2O3=1:5, wherein the molar ratio of Sb2O3, Cs2CO3 and B2O3 was 7:1:3. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 960℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 25 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 905℃, then slowly cool it to room temperature at a rate of 3.5℃ / h, and obtain gallium oxide seed crystals by spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixture for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixture. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 910℃ at a cooling rate of 30℃ / h. The temperature is then lowered at a rate of 2.5℃ / day, and the seed crystal rod is rotated at a speed of 30 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is lowered to room temperature at a rate of 40℃ / hour to obtain a gallium oxide crystal with a size of 8mm×5mm×2mm.

[0049] Example 11 (1) The compound gallium oxide single-phase polycrystalline powder and the flux Cs2CO3-B2O3 were mixed in a molar ratio of Ga2O3:Cs2CO3-B2O3=2:9, wherein the molar ratio of Cs2CO3 to B2O3 was 4:7. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 950℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 25 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 890℃, then slowly cool it to room temperature at a rate of 1℃ / h, and obtain gallium oxide seed crystals by spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is dropped from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixture for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixture. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 890℃ at a cooling rate of 10℃ / h. The temperature is then lowered at a rate of 2.5℃ / day, and the seed crystal rod is rotated at a speed of 30 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is lowered to room temperature at a rate of 40℃ / hour to obtain a gallium oxide crystal with a size of 8mm×5mm×2mm.

[0050] Example 12 (1) The compound gallium oxide crystal single-phase polycrystalline powder and the flux Cs2CO3-B2O3 were mixed in a molar ratio of Ga2O3:Cs2CO3-B2O3=2:18, wherein the molar ratio of Cs2CO3 to B2O3 was 2:5. The mixture was placed in an open platinum crucible with a diameter of 100mm×100mm and heated to 900℃ at a heating rate of 30℃ / h. The mixture was kept at the temperature for 25 hours to obtain a mixed melt. (2) Take a portion of the mixed melt and continue to cool it to 860℃, then slowly cool it to room temperature at a rate of 1.5℃ / h, and obtain gallium oxide seed crystals by spontaneous crystallization; (3) Crystal growth in compound melt: The obtained gallium oxide seed crystal is fixed on the seed crystal rod and the seed crystal is lowered from the top of the crystal growth furnace. The seed crystal is preheated on the surface of the mixture for 10 minutes, and then immersed in the surface of the mixed melt to allow the seed crystal to remelt in the mixture. The temperature is kept constant for 30 minutes, and then the temperature is reduced to the saturation temperature of 860℃ at a cooling rate of 25℃ / h. The temperature is then lowered at a rate of 2.5℃ / day, and the seed crystal rod is rotated at a speed of 30 rpm. After the crystal growth is completed, the crystal is removed from the liquid surface and the temperature is lowered to room temperature at a rate of 40℃ / hour to obtain a gallium oxide crystal with a size of 8mm×5mm×2mm.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A flux for the growth of β-gallium oxide crystals, characterized by comprising: The fluxing agent comprises at least two of an antimony-containing compound, a cesium-containing compound and a boron-containing compound.

2. The flux for beta-gallium-oxide crystal growth according to claim 1, wherein The antimony-containing compound is Sb2O3, the cesium-containing compound is Cs2CO3, CsF or CsCl, and the boron-containing compound is B2O3 or H2BO3.

3. The flux for beta-gallium-oxide crystal growth according to claim 1 or 2, characterized in that, When the fluxing agent comprises an antimony-containing compound and a cesium-containing compound, the molar ratio of the antimony-containing compound to the cesium-containing compound is (3-10):(1-4). When the fluxing agent comprises an antimony-containing compound and a boron-containing compound, the molar ratio of the antimony-containing compound to the boron-containing compound is (2-16):(2-4). When the fluxing agent comprises a cesium-containing compound and a boron-containing compound, the molar ratio of the cesium-containing compound to the boron-containing compound is (1-4):(2-8). When the fluxing agent comprises an antimony-containing compound, a cesium-containing compound and a boron-containing compound, the molar ratio of the antimony-containing compound to the cesium-containing compound to the boron-containing compound is (2-14):(1-2):(1-7).

4. A method of growing a beta-gallium-oxide crystal, characterized by, The fluxing agent of claim 1 is used for growing a β-gallium oxide crystal.

5. The method of claim 4, wherein, The method comprises the following steps: a compound gallium oxide crystal single-phase polycrystal powder and a fluxing agent are mixed and heated to melt to obtain a mixed melt; a saturation point temperature of the mixed melt is determined, a gallium oxide seed crystal is introduced into the mixed melt at a temperature higher than the saturation point temperature, and then the temperature is kept constant, and then the temperature is lowered to the saturation point temperature, and then the temperature is lowered to grow a β-gallium oxide crystal.

6. The method of claim 5, wherein, The molar ratio of the compound gallium oxide crystal single-phase polycrystal powder to the fluxing agent is (1-3):(3-20).

7. The method of claim 5, wherein, The heating and melting are performed at a temperature rising rate of 1-30 ℃ / h to 800-1100 ℃, and the temperature is kept constant for 5-80 hours.

8. The method of claim 5, wherein, The saturation point temperature is 750-1050 ℃.

9. The method of claim 5, wherein, The temperature lowering and growth are performed at a rate of 0.1-5 ℃ / day starting from the saturation point temperature, while the crystal is rotated, nucleation is induced on the seed crystal to grow the crystal, the crystal is separated from the liquid surface when the crystal grows to a desired size, and then the temperature is lowered to room temperature at a rate of 1-80 ℃ / h to obtain a β-gallium oxide crystal.

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