Metal crucible, device and method for growing gallium oxide crystals

Abstract

The embodiments of the present application provide a metal crucible, apparatus, and method for growing gallium oxide crystals. The metal crucible includes a crucible body and a crucible cover that covers the crucible body. The height of the crucible cover gradually decreases from its center position to the edge position. The edge of the crucible cover contacts the inner wall of the crucible body, and the contact point is located below the plane where the opening of the crucible body is located. The gap between the crucible cover and the crucible body can be automatically sealed by condensing the steam generated by the evaporation of the raw materials in the crucible, thereby solving the problem of continued volatilization of the gallium oxide melt at high temperatures. At the same time, because the crucible is self-sealed, the oxygen partial pressure generated by the decomposition of the raw materials in the crucible quickly reaches saturation, thereby further suppressing the decomposition of the raw materials, and allowing the growth of high-quality, large-sized gallium oxide crystals.

Description

Technical Field

[0001] The present application relates to the technical field of crystal preparation, and in particular to a metal crucible, equipment and method for growing gallium oxide crystals. Background Art

[0002] Gallium oxide is a transparent oxide semiconductor material and a wide-bandgap semiconductor crystal with a bandgap of 4.9 eV and a melting point of 1793°C. It exhibits excellent thermal and chemical stability and holds promising application prospects in high-power, high-voltage, and high-current density devices. Furthermore, gallium oxide possesses both electrical conductivity and luminescence properties, making it widely used in high-temperature gas sensors and transparent conductive optoelectronic devices.

[0003] Currently, the growth of gallium oxide crystals generally has problems such as the volatility of gallium oxide melt at high temperatures and the easy reduction of gallium oxide, which makes it difficult to obtain high-quality gallium oxide crystals. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a metal crucible, apparatus, and method for growing gallium oxide crystals, thereby solving the problem of volatilization of gallium oxide melt and easy reduction of gallium oxide at high temperatures, thereby obtaining high-quality gallium oxide crystals. The specific technical solution is as follows:

[0005] A first aspect of an embodiment of the present application provides a metal crucible, comprising a crucible body and a crucible cover covering the crucible body, wherein the crucible cover gradually decreases in height from its center position to its edge position, and the edge of the crucible cover contacts the inner wall of the crucible body, and the contact point is located below the plane where the opening of the crucible body is located.

[0006] In addition, the metal crucible for growing gallium oxide crystals provided in accordance with the first aspect of the embodiments of the present application may also have the following technical features:

[0007] In some embodiments, after the crucible cover is closed on the crucible body, the height of the crucible cover is lower than the height of the plane where the opening of the crucible body is located.

[0008] In some embodiments, the gap between the edge of the crucible cover and the inner wall of the crucible body is no greater than 0.5 mm.

[0009] In some embodiments, the inner diameter of the crucible body decreases monotonically in a direction approaching the bottom of the crucible.

[0010] In some embodiments, the metal crucible for growing gallium oxide crystals is made of iridium, rhodium, or an iridium-rhodium alloy.

[0011] According to a second aspect of the present application, there is provided an apparatus for growing gallium oxide crystals, comprising: a furnace body; a heat preservation device, the heat preservation device being located within the furnace body and having an internal space; a metal crucible for growing gallium oxide crystals, the metal crucible being the crucible described above and being placed within the internal space of the heat preservation device; and an induction coil, the induction coil being connected to the furnace body and located outside the heat preservation device, the induction coil being electromagnetically coupled to the crucible body to generate heat.

[0012] In other embodiments, the equipment for growing gallium oxide crystals includes: a furnace body; a heat preservation device, which is located in the furnace body and has an internal space; a metal crucible for growing gallium oxide crystals, which is the crucible described above and is placed in the internal space of the heat preservation device; a heating element, which is arranged on the outside of the crucible body and in the internal space of the heat preservation device; an induction coil, which is connected to the furnace body and is located outside the heat preservation device, and the induction coil is electromagnetically coupled with the heating element to generate heat.

[0013] In some other embodiments, the equipment for growing gallium oxide crystals includes: a furnace body; a heat preservation device, which is located in the furnace body and has an internal space; a metal crucible for growing gallium oxide crystals, which is the crucible described above and is placed in the internal space of the heat preservation device; and a resistance heater, which is arranged on the outside of the metal crucible and in the internal space of the heat preservation device.

[0014] In some embodiments, the equipment for growing gallium oxide crystals includes a first lifting device, which includes a first driving member, a lifting rod and a lifting frame. The first driving member is placed outside the furnace body, the lifting frame is arranged inside the furnace body, and the insulation device and the metal crucible are arranged in the lifting frame. One end of the lifting rod is connected to the driving member, and the other end passes through the top of the furnace body and is placed in the furnace body and connected to the lifting frame. The first driving member drives the lifting rod to rise and fall and drives the lifting frame to rise and fall, so that the insulation device and the metal crucible are lifted and lowered synchronously.

[0015] In other embodiments, the equipment for growing gallium oxide crystals includes a second lifting device, which includes a second driving member, a first lifting rod and a second support plate. The second driving member is placed outside the furnace body, and the second support plate is arranged inside the furnace body. The insulation device and the metal crucible are placed on the second support plate. One end of the first lifting rod is connected to the second driving member, and the other end of the first lifting rod passes through the bottom of the furnace body and is placed in the furnace body and connected to the second support plate. The second driving member drives the first lifting rod to rise and fall and drives the second support plate to rise and fall, so that the insulation device and the metal crucible are lifted and lowered synchronously.

[0016] In other embodiments, the crystal growth equipment includes a third lifting device, which includes a third driving member and a second lifting rod connected to the third driving member. The third driving member is placed outside the furnace body, one end of the second lifting rod is connected to the third driving member, and the other end of the second lifting rod is connected to the induction coil. The third driving member drives the second lifting rod to rise and fall and drives the induction coil to rise and fall synchronously.

[0017] In other embodiments, the crystal growth equipment includes a fourth lifting device, which includes a fourth driving member and a third lifting rod connected to the fourth driving member. The fourth driving member is placed outside the furnace body, one end of the third lifting rod is connected to the fourth driving member, and the other end of the third lifting rod is connected to the resistance heater. The fourth driving member drives the third lifting rod to rise and fall and drives the resistance heater to rise and fall synchronously.

[0018] A third aspect of the present application provides a method for growing gallium oxide crystals using a slow cooling method, using the apparatus for growing gallium oxide crystals described above, wherein the apparatus for growing gallium oxide crystals includes a first lifting device or a second lifting device, and the method includes at least the following steps:

[0019] Adjusting the position of the metal crucible along the height direction of the gallium oxide crystal growing device by the first lifting device or the second lifting device so that the half-height line position of the metal crucible is flush with the half-height line position of the induction coil or is higher than the half-height line position of the induction coil;

[0020] heating the gallium oxide raw material in the metal crucible at a first preset power until it is completely melted and generates some steam, wherein the steam condenses on the inner surface of the crucible cover, flows along the inner wall of the crucible cover to the contact point between the crucible cover and the crucible body, and climbs to the outside of the crucible cover at the contact point to cool and solidify, thereby sealing the crucible;

[0021] The temperature is kept constant for a certain period of time, and then the heating power is slowly reduced, so that the raw material at the bottom of the metal crucible begins to crystallize and gradually grows toward the crucible cover, so that the raw material in the entire crucible grows into gallium oxide crystals.

[0022] In other embodiments, using the apparatus for growing gallium oxide crystals as described above, the apparatus for growing gallium oxide crystals includes a first lifting device or a second lifting device, and a method for growing gallium oxide crystals using a zone melting method includes at least the following steps:

[0023] Adjusting the position of the metal crucible along the height direction of the device for growing gallium oxide crystals by the first lifting device or the second lifting device so that the bottom of the metal crucible is flush with the half-height line position of the induction coil;

[0024] Melting the gallium oxide raw material within a certain thickness on the bottom surface of the metal crucible at a second preset power to generate some vapor, which condenses on the inner surface of the crucible lid and flows along the inner wall of the crucible lid to the contact point between the crucible lid and the crucible body, and then climbs to the outside of the crucible lid at the contact point to cool and solidify, thereby sealing the crucible;

[0025] The metal crucible is adjusted to move downward by the first lifting device or the second lifting device, and the raw materials at a position flush with the half-height line of the induction coil are melted successively. The raw materials at the bottom of the metal crucible begin to crystallize and gradually grow toward the crucible cover, so that the raw materials in the entire crucible grow into gallium oxide crystals.

[0026] In yet another embodiment, using the apparatus for growing gallium oxide crystals as described above, the apparatus for growing gallium oxide crystals includes a first lifting device or a second lifting device, and a method for growing gallium oxide crystals using a crucible lowering method includes at least the following steps:

[0027] Adjusting the position of the metal crucible along the height direction of the device for growing gallium oxide crystals by a first lifting device or a second lifting device so that the bottom of the metal crucible is flush with or higher than the half-height line position of the induction coil;

[0028] Melting all the gallium oxide raw material in the metal crucible at a third preset power to generate some steam, wherein the steam condenses on an inner surface of the crucible lid, flows along the inner wall of the crucible lid to a contact point between the crucible lid and the crucible body, and then climbs to the outside of the crucible lid at the contact point to cool and solidify, thereby sealing the crucible;

[0029] The metal crucible is adjusted to move downward by the first lifting device or the second lifting device, and the raw material at the bottom of the metal crucible begins to crystallize and gradually grows toward the crucible cover, so that the raw material in the entire crucible grows into gallium oxide crystals.

[0030] The above-mentioned method for growing gallium oxide crystals further includes the following furnace annealing step after the crystal growth is completed:

[0031] Adjusting the heating power to a preset power, wherein the preset power is lower than the power required to melt the gallium oxide crystal;

[0032] Then, the position of the metal crucible is adjusted by the first lifting device or the second lifting device so that the half-height line of the metal crucible is flush with or higher than the half-height line of the induction coil;

[0033] Keep warm for not less than 10 hours at the preset power;

[0034] The temperature was lowered to room temperature at a rate of no more than 50°C / hour.

[0035] After furnace annealing, the following steps are also included: demoulding and crystallization:

[0036] Manually increase the heating power to the preset power within 1-10 seconds;

[0037] Stabilize at the preset power for 1-10 minutes;

[0038] The heating power is manually reduced to 0 within 1-10 seconds, and the difference in thermal expansion coefficient and temperature change speed between the metal crucible and the gallium oxide crystal is utilized to separate the crystal from the crucible wall and thus demold.

[0039] Beneficial effects of the embodiments of the present application:

[0040] The crucible for growing gallium oxide crystals, the apparatus for growing gallium oxide crystals, and the method for growing gallium oxide crystals provided by the embodiments of the present application have a crucible lid that gradually decreases in height from its center to its edge, the edge of the crucible lid contacts the inner wall of the crucible body, and the contact point is located below the plane of the crucible body opening. When vapor generated by evaporation of the gallium oxide melt in the crucible condenses on the inner wall of the crucible lid, the condensed vapor, under the action of gravity, slides down the inner wall of the crucible lid toward the inner wall of the crucible body, and at the point where the crucible body and the crucible lid contact, wets the gap between the two. Under capillary action, the condensed vapor rises along the gap and overflows the crucible lid. Due to the sudden drop in temperature after overflow, the condensed vapor solidifies, and after solidification, it blocks the gap, thereby sealing the crucible. Since the gap between the crucible lid and the crucible body can be automatically sealed by the vapor generated by the evaporation of the raw materials in the crucible, the problem of continued volatilization of the gallium oxide melt at high temperatures can be solved. At the same time, since the crucible is self-sealed, the oxygen partial pressure generated by the decomposition of the gallium oxide raw material in the crucible quickly reaches saturation, thereby inhibiting the further decomposition of the raw material. This solves the problem of the gallium oxide melt being easily reduced at high temperatures, which is beneficial to improving the quality of the grown gallium oxide crystals.

[0041] Of course, it is not necessary to achieve all the advantages described above at the same time when implementing any product or method of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0043] Figure 1 A schematic structural diagram of a crucible provided in an embodiment of the present application, wherein the crucible is not filled with raw materials;

[0044] Figure 2 for Figure 1 a middle crucible, wherein the crucible is filled with raw materials;

[0045] Figure 3 for Figure 1 Crucible cover for the middle crucible;

[0046] Figure 4 A schematic structural diagram of another embodiment of the crucible provided in an embodiment of the present application, wherein a seed crystal holder is provided at the bottom of the crucible body;

[0047] Figure 5a A schematic diagram of a non-working state of a crystal growth device provided in an embodiment of the present application;

[0048] Figure 5b A schematic diagram of an initial working state of a crystal growth device provided in an embodiment of the present application;

[0049] Figure 5c A schematic diagram of the final working state of the crystal growth apparatus provided in an embodiment of the present application;

[0050] Figure 6 for Figure 5a A top view of the crystal growth equipment;

[0051] Figure 7 A schematic structural diagram of a heat preservation device and its internal structure of a crystal growth device provided in an embodiment of the present application;

[0052] Figure 8 A schematic diagram of the positional relationship between the hanging plate and the induction coil of the first lifting device;

[0053] Figure 9 It is a structural schematic diagram of the cross support of the first lifting device;

[0054] Figure 10 This is a schematic structural diagram of another embodiment of the crystal growth equipment provided in the embodiment of the present application.

[0055] The figures are marked as follows: metal crucible 10; crucible body 11; opening position 111; seed crystal holder 112; crucible cover 12; center position 12a; edge position 12b; furnace body 20; insulation device 30; first layer 31; second layer 32; third layer 33; induction coil 40; first lifting device 50; lifting rod 51; vertical rod 511; cross support 512; mounting hole 5121; lifting frame 52; hanging plate 521; first support plate 522; vertical rod 523; second lifting device 60; first lifting rod 61; second support plate 62; gallium oxide melt 70; gallium oxide seed crystal 80. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field based on this application are within the scope of protection of this application.

[0057] In a first aspect, an embodiment of the present application provides a metal crucible 10 for growing gallium oxide crystals, such as Figure 1As shown, the metal crucible 10 includes a crucible body 11 and a crucible cover 12 covering the crucible body 11. The crucible cover 12 gradually decreases in height from its center position 12a to the edge position 12b. The edge of the crucible cover 12 contacts the inner wall of the crucible body 11, and the contact point is located below the plane where the opening of the crucible body 11 is located.

[0058] In this embodiment, the crucible lid 12 is attached to the crucible body 11 in a simple overlapping relationship. Since there are no other sealing measures, a gap inevitably exists at the contact point between the crucible lid 12 and the crucible body 11. To improve the sealing effect between the crucible lid 12 and the crucible body 11, the gap between the crucible lid 12 and the inner wall of the crucible body 11 is required to be as small as possible: the gap between the edge of the crucible lid 12 and the inner wall of the crucible body 11 is no greater than 0.5 mm, and preferably no greater than 0.2 mm.

[0059] When the vapor generated by the evaporation of the gallium oxide melt 70 in the metal crucible 10 condenses on the inner wall of the crucible lid 12, the height of the crucible lid 12 gradually decreases from the center position 12a to the edge position 12b. Under the action of gravity, the condensed droplets of vapor will slide along the inner wall of the crucible lid 12 toward the inner wall of the crucible body 11. At the point where the crucible body 11 and the crucible lid 12 contact, they wet the gap between the two and, under capillary action, rise upward along the gap and overflow the crucible lid 12. Due to the sudden drop in temperature after overflowing, they solidify and automatically block the gap after solidification, thereby sealing the metal crucible 10. Placing the contact point between the crucible lid 12 and the crucible body 11 below the opening of the crucible body 11 facilitates the droplets to rise along the inner wall of the crucible body 11, thereby better sealing the metal crucible 10.

[0060] Because the gap between the crucible lid 12 and the crucible body 11 can be automatically sealed by condensing the vapor generated by the evaporation of the raw materials within the metal crucible 10, the problem of continued volatilization of the gallium oxide melt 70 at high temperatures can be solved. Furthermore, because the metal crucible 10 is automatically sealed, the oxygen partial pressure generated by the decomposition and reduction of the gallium oxide raw materials within the metal crucible 10 quickly reaches saturation, thereby suppressing the decomposition and reduction of the raw materials, effectively solving the problem of gallium oxide being easily decomposed and reduced. It should be noted that the center position 12a refers to the center of the curved surface of the crucible lid 12 in the overall thickness direction of the crucible lid 12, and does not refer solely to the center of the inner or outer surface or the middle surface in the thickness direction.

[0061] In some embodiments, as Figure 1 As shown, after the crucible cover 12 is covered on the crucible body 11 , the height of the crucible cover 12 is lower than the height of the plane where the opening of the crucible body 11 is located.

[0062] In this embodiment, the crucible cover 12 is located below the plane of the opening of the crucible body 11, that is, the height of the highest point of the crucible cover 12 is lower than the height of the plane of the opening of the crucible body 11. When the metal crucible 10 is in use, the top insulation material is in contact with the metal crucible 10 as closely as possible, thereby improving the insulation effect of the metal crucible 10.

[0063] Alternatively, as Figure 1 As shown, the center position 12a of the outer surface of the crucible cover 12 is located 1 mm to 3 mm below the opening position 111 of the crucible body 11, for example, 1 mm, 2 mm or 3 mm.

[0064] The center 12a of the outer surface is the highest point of the crucible lid 12. If the center 12a is located below the opening 111 of the crucible body 11, the entire crucible lid 12 can be located below the opening 111 of the crucible body 11. The center 12a is 1 mm to 3 mm below the opening 111 of the crucible body 11. When insulating material is placed above the crucible body 11, the gap between the insulating material and the metal crucible 10 is minimized, thereby improving the insulation effect on the metal crucible 10 and preventing interference with the crucible lid 12, thereby preventing damage to the crucible lid 12.

[0065] like Figure 3 As shown, the crucible cover 12 is symmetrical about an axis passing through the center position 12a. For example, the crucible cover 12 can be spherical. The crucible cover 12 gradually decreases in height from the center position 12a to the edge position 12b, allowing condensed droplets to slide smoothly toward the edge position 12b in all directions, thereby sealing the gap between the crucible cover 12 and the crucible body 11.

[0066] The crucible body 11 and crucible lid 12 are made of metallic iridium, rhodium, or an iridium-rhodium alloy. Iridium and rhodium have relatively high melting points, at 2454°C and 1966°C, respectively, both significantly higher than the melting point of gallium oxide (1793°C). Compared to platinum-rhodium alloys, these have a wider operating range and can be used to produce larger crystals. This is because larger crystals require more melted gallium oxide raw material, and a greater superheat is required to melt all the raw material. Since the melting point of platinum-rhodium alloys is not much higher than that of gallium oxide, the operating range is smaller, making it difficult to produce larger gallium oxide crystals.

[0067] After crystal growth and furnace annealing are completed, a rapid heating and cooling method is adopted, and the property that the expansion coefficients of metal iridium, rhodium and their alloys are large, while the expansion coefficient of gallium oxide crystals is small, is utilized to achieve rapid demolding of the gallium oxide crystals from the metal crucible 10, thereby making the metal crucible 10 reusable and reducing production costs.

[0068] Optionally, the wall thickness of the crucible body 11 is 1mm-5mm, and the wall thickness of the crucible cover 12 is 1mm-5mm. Preferably, the wall thickness of the crucible body 11 is 1.5mm-3mm, and the wall thickness of the crucible cover 12 is 1.5mm-3mm. For example, the wall thickness of the crucible body 11 can be 1.5mm, 2mm, 3mm, etc., and the wall thickness of the crucible cover 12 can be 1.5mm, 2mm, 3mm, etc.

[0069] It should be noted that, during use, the metal crucible 10 Figure 2 As shown, there is a certain distance between the crucible cover 12 and the surface of the gallium oxide melt 70 to prevent the raw materials from sticking to the crucible cover 12, that is: the inner diameter of the crucible body 11 at the surface < the outer diameter of the bottom of the crucible cover 12 < the inner diameter of the opening of the crucible body 11.

[0070] In some embodiments, as Figure 1 、 Figure 2 As shown, the inner diameter of the crucible body 11 decreases monotonically along the direction approaching the bottom of the metal crucible 10.

[0071] The inner diameter of the crucible body 11 decreases monotonically from top to bottom, so that the crystal growth shape is thick at the top and thin at the bottom. In addition, the inner surface of the crucible is required to be smooth, which can reduce the friction between the crystal and the crucible body 11 when it is taken out from the opening of the crucible body 11, which is conducive to the demolding of the crystal.

[0072] The inner diameter of the crucible body 11 decreases monotonically along the direction approaching the bottom of the metal crucible 10, which means that the inner diameter is always decreasing, but the speed of decrease can be large or small, or can be sudden, so as to facilitate crystal growth and demolding after crystal growth.

[0073] Among them, such as Figure 1 、 Figure 2 As shown, the metal crucible 10 may not have a seed crystal holder 112 at the bottom; Figure 4 As shown, a seed crystal holder 112 may also be provided at the bottom of the metal crucible 10 .

[0074] A second aspect of the present invention provides a device for growing gallium oxide crystals, such as Figure 5a 、 Figure 5b 、 Figure 5c 、 Figure 6 As shown, the apparatus for growing gallium oxide crystals includes: a furnace body 20, a heat preservation device 30, a metal crucible 10 for growing gallium oxide crystals, and an induction coil 40. The heat preservation device 30 is located within the furnace body 20 and has an internal space. The metal crucible 10 is the metal crucible 10 described above and is placed within the internal space of the heat preservation device 30. The induction coil 40 is connected to the furnace body 20 and is located outside the heat preservation device 30. The induction coil 40 is electromagnetically coupled to the crucible body 11 to generate heat. The heating power can be automatically controlled by a program or manually controlled (can be raised and lowered quickly).

[0075] The metal crucible 10 filled with gallium oxide raw materials is placed into the furnace body 20. The four sides of the metal crucible 10 and the top and bottom of the metal crucible 10 are surrounded by the heat preservation device 30 to improve the temperature uniformity inside the metal crucible 10. Figure 7 As shown, the insulation device 30 can be divided into: a first layer 31 close to the metal crucible 10 and a second layer 32 and a third layer 33 respectively away from the metal crucible 10. The temperature of the first layer 31 and the second layer 32 is relatively high, for example, higher than 1400°C, and zirconia material can be used. The temperature of the third layer 33 is relatively low, for example, lower than 1400°C, and cheaper alumina hollow ball bricks, corundum bricks, mullite bricks, etc. can be used to reduce costs. For the first layer 31, zirconium oxide sand can be used for insulation around the metal crucible 10 and at the bottom of the metal crucible 10 (this is the first layer 31). Zirconium oxide sand can adapt to the shape of the metal crucible 10 and fully contact the outer surface of the metal crucible 10, reducing the porosity, thereby improving the insulation effect, and zirconium oxide sand can support the metal crucible 10 in all directions, and it is convenient to remove the metal crucible 10 after the growth is completed; on the outside of the first layer 31 and the top of the metal crucible 10, that is, above the crucible cover 12, zirconium oxide fiber bricks or zirconium oxide hollow ball bricks (this is the second layer 32) can be used for insulation. On the one hand, it is convenient for disassembly, and on the other hand, it prevents the insulation material from falling into the metal crucible 10 and contaminating the raw materials.

[0076] The induction coil 40 is connected to the furnace body 20 and electromagnetically couples with the crucible body 11 to generate heat. When energized, the induction coil 40 generates a continuously changing alternating magnetic field. The conductor of the crucible body 11 generates eddy currents within the alternating magnetic field. The Joule effect of these eddy currents raises the temperature of the crucible body 11, thereby heating the crucible body 11 and heating the raw materials in the metal crucible 10. Furthermore, the temperature of the crucible body 11 can be controlled by varying the power of the induction coil 40. Electromagnetic coupling heating offers advantages such as rapid heating and energy conservation.

[0077] In other embodiments, the apparatus for growing gallium oxide crystals further includes a heating element (not shown). The heating element is disposed outside the crucible 11 and within the interior space of the heat-insulating device 30. The induction coil 40 is electromagnetically coupled to the heating element to generate heat. Specifically, the heating element is in the form of a sleeve and is disposed around the outside of the crucible 11.

[0078] In some embodiments, as Figure 5a 、 Figure 5b 、 Figure 5c and Figure 6As shown, the equipment for growing gallium oxide crystals includes a first lifting device 50, which includes a first driving member (not shown), a lifting rod 51 and a lifting frame 52. The first driving member is placed outside the furnace body 20, the lifting frame 52 is arranged inside the furnace body 20, and the insulation device 30 and the metal crucible 10 are arranged in the lifting frame 52. One end of the lifting rod 51 is connected to the driving member, and the other end passes through the top of the furnace body 20 and is placed in the furnace body 20 and connected to the lifting frame 52. The first driving member drives the lifting rod 51 to rise and fall and drives the lifting frame 52 to rise and fall, so that the insulation device 30 and the metal crucible 10 rise and fall synchronously.

[0079] In this embodiment, the first lifting device 50 lifts and lowers the heat preservation device 30 and the metal crucible 10 located in the heat preservation device 30 from the top of the furnace body 20. The first driving member can be a combination of a servo motor and a reduction motor, or an integrated servo reduction motor. Figure 5a 、 Figure 5b 、 Figure 5c and Figure 8 As shown, the top of the lifting frame 52 is a hanging plate 521, and the bottom is a first support plate 522. The length of the hanging plate 521 and the first support plate 522 is greater than the length of the long side of the heat preservation device 30 parallel to the plane where the hanging plate 521 and the first support plate 522 are located. The width of the hanging plate 521 and the first support plate 522 is greater than or equal to half of the wide side of the heat preservation device 30 parallel to the plane where the hanging plate 521 and the first support plate 522 are located. The hanging plate 521 and the first support plate 522 can be fiberglass boards or machinable ceramic boards. The hanging plate 521 and the first support plate 522 are connected by four vertical rods 523 to avoid interference with the installation of the induction coil 40, wherein the vertical rods 523 can be fiberglass rods or machinable ceramic rods. Combined Figure 5a 、 Figure 5b 、 Figure 5c and Figure 9 As shown, the lifting rod 51 includes a vertical rod 511 and a cross support 512. The cross support 512 is placed at the bottom of the hanging plate 521. The vertical rod 511 passes through the hanging plate 521 and is connected to the center of the cross support 512. The center of the cross support 512 has a mounting hole 5121 or a mounting groove. The cross support 512 can ensure the stability of the lifting rod 51 during the lifting movement and prevent uneven force from causing deflection during the lifting process. Since the cross support 512 is made of metal, it can be made into a cross support 512 to reduce the effective passage area of ​​the magnetic flux lines, thereby reducing the induced current and avoiding heat.

[0080] In other embodiments, the apparatus for growing gallium oxide crystals includes a second lifting device 60, such as Figure 10As shown, the second lifting device 60 includes a second driving member (not shown), a first lifting rod 61 and a second support plate 62. The second driving member is placed outside the furnace body 20, and the second support plate 62 is arranged inside the furnace body 20. The insulation device 30 and the metal crucible 10 are placed on the second support plate 62. One end of the first lifting rod 61 is connected to the second driving member, and the other end of the first lifting rod 61 passes through the bottom of the furnace body 20 and is placed in the furnace body 20 and is connected to the second support plate 62. The second driving member drives the first lifting rod 61 to rise and fall and drives the second support plate 62 to rise and fall, so that the insulation device 30 and the metal crucible 10 rise and fall synchronously.

[0081] In this embodiment, the second lifting device 60 lifts and lowers the heat preservation device 30 and the metal crucible 10 located in the heat preservation device 30 from the bottom of the furnace body 20. The second driving member can be a combination of a servo motor and a reduction motor, or an integrated servo reduction motor. The second driving member lifts and lowers the heat preservation device 30 and the metal crucible 10 located in the heat preservation device 30 from the bottom of the furnace body 20, which helps to simplify the structure of the second lifting device 60. That is, in order to achieve the lifting movement of the heat preservation device 30, only a second support plate 62 is needed to support the heat preservation device 30, and the second support plate 62 is connected to the first lifting rod 61 of the second driving member. Compared with the lifting frame 52, the structure is simpler and, therefore, it is the preferred lifting device.

[0082] In yet other embodiments, an apparatus for growing gallium oxide crystals comprises:

[0083] The furnace body 20, a heat-insulating device 30, a metal crucible 10 for growing gallium oxide crystals, and a resistance heater (not shown) are provided. The heat-insulating device 30 is located within the furnace body 20 and has an internal space. The metal crucible 10 is the metal crucible 10 described above and is placed within the internal space of the heat-insulating device 30. The resistance heater is located outside the metal crucible 10 and within the internal space of the heat-insulating device 30.

[0084] The resistance heater can be made of high-melting-point metal wires, sheets, or thin rods, such as tungsten (melting point: 3410°C), molybdenum (melting point: 2620°C), tantalum (melting point: 2996°C), or niobium (melting point: 2468°C). The heating power can be controlled by a program or manually (with rapid adjustment).

[0085] In other embodiments, the crystal growth equipment includes a third lifting device (not shown in the figure), the third lifting device includes a third driving member and a second lifting rod connected to the third driving member, the third driving member is placed outside the furnace body 20, one end of the second lifting rod is connected to the third driving member, and the other end of the second lifting rod is connected to the induction coil 40. The third driving member drives the second lifting rod to rise and fall and drives the induction coil 40 to rise and fall synchronously.

[0086] In other embodiments, the crystal growth equipment includes a fourth lifting device (not shown in the figure), the fourth lifting device includes a fourth driving member and a third lifting rod connected to the fourth driving member, the fourth driving member is placed outside the furnace body 20, one end of the third lifting rod is connected to the fourth driving member, and the other end of the third lifting rod is connected to the resistance heater, and the fourth driving member drives the third lifting rod to rise and fall and drives the resistance heater to rise and fall synchronously.

[0087] The induction coil 40 is raised or lowered by the third lifting device, or the resistance heater is raised or lowered by the fourth lifting device, while the metal crucible 10 is kept stationary, thereby controlling the temperature change inside the metal crucible 10. The third and fourth lifting devices can be raised from either the top or the bottom of the furnace body, which is not limited in this application.

[0088] The first lifting device 50 or the second lifting device 60 can move in either up or down direction, with a fast speed of 1-100 mm / min for loading and unloading the furnace and a slow speed of 0.1-10 mm / h for crystal growth. Both require smooth operation without vibration or jumping, and can switch between fast and slow gears at will, with stepless speed adjustment within each gear. The axial stroke of the first lifting device 50 or the second lifting device 60 is greater than the sum of the height of the induction coil 40 or the resistance heater and the height of the metal crucible 10 to ensure that the metal crucible 10 can pass through the high-temperature zone from its bottom to the top. The high-temperature zone refers to the area near the half-height line of the induction coil or the resistance heater, and the bottom lifting method of the second lifting device 60 is preferred.

[0089] A third aspect of the present application provides a method for growing gallium oxide crystals using a slow cooling method, using the apparatus for growing gallium oxide crystals described above, the apparatus for growing gallium oxide crystals including a first lifting device 50 or a second lifting device 60, and at least comprising the following steps:

[0090] A1: Along the height direction of the equipment for growing gallium oxide crystals, the position of the metal crucible 10 is adjusted by the first lifting device 50 or the second lifting device 60 so that the half-height line position of the metal crucible 10 is flush with the half-height line position of the induction coil 40 or higher than the half-height line position of the induction coil 40.

[0091] A2: At a first preset power, the gallium oxide raw material in the metal crucible 10 is heated until it is completely melted and some steam is generated. The steam condenses on the inner surface of the crucible cover 12 and flows along the inner wall of the crucible cover 12 to the contact point between the crucible cover 12 and the crucible body 11. At the contact point, it climbs to the outside of the crucible cover 12 to cool and solidify, thereby sealing the crucible 10.

[0092] A3: Keep the temperature for a certain period of time (not less than 10 hours), then slowly reduce the heating power so that the raw material at the coldest bottom of the metal crucible 10 begins to crystallize and gradually grows toward the crucible cover 12, so that the raw material in the entire crucible grows into gallium oxide crystals.

[0093] like Figure 5a As shown, the initial height of the metal crucible 10 is located above the induction coil 40. The position of the metal crucible 10 is adjusted by the first lifting device 50 so that the half-height line position of the metal crucible 10 is higher than the half-height line position of the induction coil 40, as shown in FIG. Figure 5b The position above the half-height line of the induction coil 40 is generally controlled so that the height difference between the half-height lines of the two is between 0 mm and 10 mm, that is, slightly above the half-height line of the induction coil 40 .

[0094] By aligning the half-height line of the metal crucible 10 with or slightly above the half-height line of the induction coil 40, the temperature of the gallium oxide melt 70 within the metal crucible 10 is made as uniform as possible. The metal crucible 10 is coaxial with the induction coil 40. Because only the sidewalls of the crucible body 11 of the metal crucible 10 are inductively heated, and the crucible body 11 is roughly truncated with a large mouth and a small bottom, the heat generated by the sidewalls of the crucible body 11 decreases from top to bottom. The top and bottom of the metal crucible 10, however, do not generate heat due to the skin effect of induction heating, but only dissipate heat. Furthermore, vapor evaporation naturally follows a bottom-up process. Therefore, the temperature distribution within the gallium oxide melt 70 generally follows the following characteristics: sidewall temperature > top temperature > bottom temperature. Even if the insulation effect of the heat preservation device 30 is good, temperature deviation is still inevitable. The temperature is highest at the half-height line position of the induction coil 40. Therefore, setting the half-height line position of the metal crucible 10 to be flush with the half-height line position of the induction coil 40 is conducive to uniform temperature of the gallium oxide melt 70 in the metal crucible 10; when the inner diameter of the crucible body 11 decreases monotonically in the direction close to the bottom of the metal crucible 10, setting the half-height line position of the metal crucible 10 to be slightly higher than the half-height line position of the induction coil 40 can compensate to a certain extent for the effect of uneven heating due to the larger upper part and smaller lower part of the metal crucible 10, so that the temperature of the gallium oxide melt 70 in the metal crucible 10 tends to be uniform.

[0095] In this embodiment, the raw materials in the metal crucible 10 are heated until completely melted. During the initial melting phase, the volatilized gallium oxide vapor condenses on the smooth inner surface of the crucible lid 12 and flows downward along the inner surface of the crucible lid 12, inevitably wetting the entire gap between the crucible lid 12 and the inner wall of the crucible body 11. Furthermore, because the crucible opening of the metal crucible 10 is relatively cold, the condensed and reflowed gallium oxide melt at this contact point rises along the contact gap to the outside of the crucible lid 12 due to capillary action, where it solidifies as the temperature drops. In other words, the only gap in the entire metal crucible 10 that could potentially leak air is automatically sealed by the condensed and reflowed gallium oxide melt adhering to it due to capillary infiltration, cooling, and solidification along the outer surface of the crucible lid 12. This prevents further vapor leakage from the crucible, resolving the prior art issue of the high volatility of gallium oxide melt 70 at high temperatures within the metal crucible 10. Since the steam no longer leaks out, the oxygen partial pressure generated by the decomposition and reduction of gallium oxide in the crucible quickly reaches saturation, which can inhibit the further decomposition of gallium oxide, thus solving the problem of gallium oxide being easily decomposed and reduced.

[0096] Then, the heating power is slowly reduced (i.e., the temperature of the raw materials is slowly reduced). The speed of power reduction is determined by experiments to ensure that spontaneous crystals appear first at the bottom center of the metal crucible 10, where the relative temperature is the lowest, grow preferentially, and then gradually induce the entire crucible of raw materials to grow into crystals, while new spontaneous crystals rarely or never appear at other locations. Generally speaking, the growth free energy is less than the nucleation free energy, i.e., it is easier for the gallium oxide melt 70 to continue growing on the already formed crystal nuclei, while it is more difficult for spontaneous crystallization to generate new crystal nuclei. In addition, the viscosity of the gallium oxide melt 70 is not high, and the growth elements are easy to migrate, which is more conducive to the preferential growth of the first spontaneous crystals into crystals throughout the crucible.

[0097] In some other embodiments, a method for growing gallium oxide crystals using a melting zone method includes at least the following steps:

[0098] B1: along the height direction of the gallium oxide crystal growing apparatus, the position of the metal crucible 10 is adjusted by the first lifting device 50 or the second lifting device 60 so that the bottom of the metal crucible 10 is flush with the half-height line position of the induction coil 40 .

[0099] B2: At a second preset power, the gallium oxide raw material within a certain thickness at the bottom of the metal crucible 10 is melted to generate some steam. The steam condenses on the inner surface of the crucible lid 12, flows along the inner wall of the crucible lid 12 to the contact point between the crucible lid 12 and the crucible body 11, and then climbs to the outside of the crucible lid 12 at the contact point to cool and solidify, thereby sealing the crucible 10.

[0100] B3: The metal crucible 10 is adjusted to move downward by the first lifting device 50 or the second lifting device 60. The raw materials at the half-height line of the induction coil 40 are melted successively. The raw materials at the bottom of the metal crucible 10 begin to crystallize due to the decrease in temperature and gradually grow toward the crucible cover 12, so that the raw materials in the entire crucible grow into gallium oxide crystals.

[0101] This method differs from the aforementioned slow cooling method in that the initial position of the metal crucible 10 is different: the bottom of the crucible 10 is flush with the mid-height line of the induction coil 40. Rather than melting the entirety of the material in the crucible 10, only the section of material flush with the mid-height line of the induction coil 40 is melted. The crucible 10 is then slowly moved downward, melting the material layer by layer. This layer-by-layer melting method requires less heating power and reduces the volume of the high-temperature zone above the melting point of gallium oxide. Consequently, overheating of the gallium oxide melt 70 is minimized, and volatilization and valence changes of gallium oxide are less likely to occur. Stabilize the power of the heating power supply at this value; slowly but continuously lower the metal crucible 10, starting with melting the raw materials at the bottom of the crucible 10. As the crucible 10 descends, the temperature of the raw materials at the bottom of the crucible 10 gradually decreases, and the raw materials at the center of the bottom of the crucible 10 (the coldest point on the same horizontal plane) first form a single spontaneous crystal. Then, taking advantage of this coldest location, the single spontaneous crystal gradually expands. As the crucible 10 continues to descend, the raw materials in the crucible melt layer by layer from bottom to top, and then grow into gallium oxide crystals in the same lattice arrangement as the first spontaneous crystal to form. Once the crucible top drops below the bottom edge of the induction coil, the entire crucible of raw materials has completely melted and crystallized, forming a single, large crystal.

[0102] In some further embodiments, a method for growing gallium oxide crystals using a crucible drop method includes at least the following steps:

[0103] C1: along the height direction of the above-mentioned gallium oxide crystal growing device, the position of the metal crucible 10 is adjusted by the first lifting device 50 or the second lifting device 60 so that the half-height line position of the metal crucible 10 is flush with the half-height line position of the induction coil 40 or slightly higher than the half-height line position of the induction coil 40, such as Figure 5b shown.

[0104] C2: At a third preset power, all the gallium oxide raw materials in the metal crucible 10 are melted, and some steam is generated. The steam condenses on the inner surface of the crucible cover 12 and flows along the inner wall of the crucible cover 12 to the contact point between the crucible cover 12 and the crucible body 11. At the contact point, the steam rises to the outside of the crucible cover 12 to cool and solidify, thereby sealing the crucible 10.

[0105] C3: The metal crucible 10 is adjusted to move downward by the first lifting device 50 or the second lifting device 60. The raw materials at the bottom of the metal crucible 10 begin to crystallize and gradually grow toward the crucible cover 12, so that the entire crucible of raw materials grows into gallium oxide crystals. Figure 5c shown.

[0106] The differences from the zone melting method are: (1) the initial position of the metal crucible 10 is different. The initial position of the metal crucible 10 is the same as in the slow cooling method, located at or slightly above the half-height line of the induction coil 40; and (2) the amount of gallium oxide melt 70 melted varies. The crucible lowering method requires the entire gallium oxide melt 70 to be melted. Similar to the zone melting method, the metal crucible 10 also needs to be moved downward. Taking advantage of the fact that the bottom center of the metal crucible 10 is the coldest, where spontaneous crystallization occurs first, the metal crucible 10 preferentially grows as it descends, inducing the entire crucible of molten gallium oxide 70 to grow into crystals.

[0107] In the above three methods, the metal crucible 10 must be loaded before adjusting its position. The high-purity gallium oxide powder can be compacted before loading. The method of "melting-adding compacted material-melting again-adding again..." can be used to repeatedly load the material until the upper surface of the gallium oxide melt is lower than the upper opening of the crucible by about 20% of the net height of the crucible, that is, the volume of the material accounts for about 80% of the volume of the crucible body 11. After loading, the furnace is vacuumed and the furnace is pumped to 1 Pa level with a mechanical pump. Argon or carbon dioxide gas can be filled in the furnace as a protective atmosphere with a pressure of 1 Pa-10 5 Adjustable and controllable within the Pa range, with a pressure control accuracy of ±5%. The leakage rate of the vacuum system is required to be no more than 10 -5 Pa·m 3 The vacuuming step may be performed before or after the position of the metal crucible 10 is adjusted, and this application does not impose any limitation thereto.

[0108] It is understood that in the above three methods, in order to achieve the change in the relative position of the metal crucible 10 and the induction coil 40, the position of the induction coil 40 can also be adjusted by a third lifting device. When the heating component of the equipment for growing gallium oxide crystals is a resistance heater, the relative position of the metal crucible 10 and the induction coil 40 corresponds to the relative position of the metal crucible 10 and the resistance heater, and the fourth lifting device can be used to raise and lower the resistance heater to achieve the change in the relative position of the two. The above method for growing gallium oxide crystals also includes the following furnace annealing steps after the crystal growth is completed:

[0109] The heating power is adjusted to a preset power, which is lower than the power required for melting the gallium oxide crystals in the crucible.

[0110] Then, the position of the metal crucible 10 is adjusted by the first lifting device 50 or the second lifting device 60 so that the half-height line of the metal crucible 10 is flush with or higher than the half-height line of the induction coil 40 .

[0111] Keep warm for at least 10 hours at the preset power.

[0112] The temperature was lowered to room temperature at a rate of no more than 50°C / hour.

[0113] It should be noted that for the zone melting method and the crucible lowering method, there is a step of adjusting the position of the metal crucible 10, while for the slow cooling method, there is no step of adjusting the position of the metal crucible 10, and the other steps are the same.

[0114] The preset power is a power that does not melt the crystallized gallium oxide crystals in the metal crucible 10 but is as high as possible, because the higher the annealing temperature, the more thorough the stress elimination.

[0115] After the power is adjusted to the preset power, the half-height line of the metal crucible 10 is aligned with or higher than the half-height line of the induction coil 40 . Here, "higher" still means that the height difference between the half-height lines of the two is 0 mm-10 mm. This is conducive to uniform temperature in the metal crucible 10 .

[0116] Keep the temperature at the preset power for at least 10 hours, for example, more than 10 hours, to make the temperature of the entire crucible of crystals as uniform and stable as possible; then slowly cool down at a cooling rate no faster than 50°C / hour, so that the gallium oxide crystals are annealed to room temperature with the furnace to eliminate stress in the crystals.

[0117] After furnace annealing, the following steps are also included: demoulding and crystal removal:

[0118] Manually increase the heating power to the above preset power within 1-10 seconds.

[0119] Stabilize at the preset power for 1-10 minutes;

[0120] The heating power is manually reduced to 0 within 1-10 seconds, and the difference in thermal expansion coefficient and temperature change speed between the metal crucible 10 and the gallium oxide crystal is utilized to separate the crystal from the crucible wall and thereby demold the crucible.

[0121] Specifically, the demolding and crystal removal steps are as follows: before opening the furnace to remove the crystal, first manually and quickly (1-10 seconds) increase the heating power to a preset power, i.e., the annealing starting value (a power as high as possible that will not melt the crystal in the crucible). After stabilization for 1-10 minutes, immediately and manually and quickly (1-10 seconds) reduce the power to 0. Utilizing the different thermal expansion coefficients of iridium, rhodium, and their alloys and gallium oxide crystals, the former are heated faster and to a higher temperature, while the latter are heated slower and to a lower temperature. This allows the metal crucible 10 and the gallium oxide crystal to separate due to the difference in thermal expansion: within the temperature range of 25-500°C, the expansion coefficients of the gallium oxide crystal in the three axes a, b, and c are: 4.7×10 -6 / ℃、5.45×10 -6 / ℃、5.35×10 -6 / ℃; at room temperature, the expansion coefficient of iridium is about 6.4×10 -6 / ℃, the expansion coefficient of rhodium is about 8.2×10 -6 / ℃ - approximately 17%-36% and 50%-74% greater than the above-mentioned values ​​for gallium oxide, respectively.

[0122] The above three methods all use the metal crucible 10 and can achieve self-sealing of the metal crucible 10 at the initial stage of gallium oxide melting, i.e., through the volatilized steam, thereby effectively solving the problem of the gallium oxide melt 70 volatilizing and being easily decomposed and reduced.

[0123] The above three methods may all use gallium oxide seed crystals 80 to induce initial crystallization, or may not use gallium oxide seed crystals 80 , which is not limited in this application.

[0124] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0125] Each embodiment in this specification is described in a related manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0126] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application are included in the scope of protection of the present application.

Claims

1. A metal crucible for growing gallium oxide crystals, characterized in that: The metal crucible includes a crucible body and a crucible cover covering the crucible body, the crucible cover overlaps the crucible body, the gap between the edge of the crucible cover and the inner wall of the crucible body is no more than 0.5 mm, the height of the crucible cover gradually decreases from its center position to the edge position, the edge of the crucible cover contacts the inner wall of the crucible body, and the contact point is located below the plane where the opening of the crucible body is located.

2. The metal crucible for growing gallium oxide crystals according to claim 1, characterized in that: After the crucible cover is closed on the crucible body, the height of the crucible cover is lower than the height of the plane where the opening of the crucible body is located.

3. The metal crucible for growing gallium oxide crystals according to any one of claims 1 to 2, characterized in that: The inner diameter of the crucible body decreases monotonically in a direction approaching the bottom of the crucible.

4. The metal crucible for growing gallium oxide crystals according to claim 3, characterized in that: The metal material includes: iridium, rhodium or iridium-rhodium alloy.

5. A device for growing gallium oxide crystals, characterized in that The equipment for growing gallium oxide crystals comprises: furnace body; a heat-insulating device, the heat-insulating device being located in the furnace body and having an internal space; A metal crucible for growing gallium oxide crystals, wherein the metal crucible is the crucible according to any one of claims 1 to 4, and the metal crucible is placed in the internal space of the heat preservation device; An induction coil is connected to the furnace body and is located outside the heat preservation device. The induction coil is electromagnetically coupled with the crucible body to generate heat.

6. An apparatus for growing gallium oxide crystals, characterized in that: The equipment for growing gallium oxide crystals comprises: furnace body; a heat-insulating device, the heat-insulating device being located in the furnace body and having an internal space; A metal crucible for growing gallium oxide crystals, wherein the metal crucible is the crucible according to any one of claims 1 to 4, and the metal crucible is placed in the internal space of the heat preservation device; a heating element, the heating element being arranged outside the crucible body and inside the internal space of the heat preservation device; The induction coil is connected to the furnace body and is located outside the heat preservation device. The induction coil is electromagnetically coupled with the heating element to generate heat.

7. A device for growing gallium oxide crystals, characterized in that The equipment for growing gallium oxide crystals comprises: furnace body; a heat-insulating device, the heat-insulating device being located in the furnace body and having an internal space; A metal crucible for growing gallium oxide crystals, wherein the metal crucible is the crucible according to any one of claims 1 to 4, and the metal crucible is placed in the internal space of the heat preservation device; A resistance heater is arranged outside the metal crucible and inside the inner space of the heat preservation device.

8. The apparatus for growing gallium oxide crystals according to any one of claims 5 to 7, characterized in that: The crystal growth equipment includes a first lifting device, which includes a first driving member, a lifting rod and a lifting frame. The first driving member is placed outside the furnace body, the lifting frame is arranged inside the furnace body, and the insulation device and the metal crucible are arranged in the lifting frame. One end of the lifting rod is connected to the driving member, and the other end passes through the top of the furnace body and is placed in the furnace body and connected to the lifting frame. The first driving member drives the lifting rod to rise and fall and drives the lifting frame to rise and fall, so that the insulation device and the metal crucible are lifted and lowered synchronously.

9. The apparatus for growing gallium oxide crystals according to any one of claims 5 to 7, characterized in that: The crystal growth equipment includes a second lifting device, which includes a second driving member, a first lifting rod and a second support plate. The second driving member is placed outside the furnace body, and the second support plate is arranged inside the furnace body. The insulation device and the metal crucible are placed on the second support plate. One end of the first lifting rod is connected to the second driving member, and the other end of the first lifting rod passes through the bottom of the furnace body and is placed in the furnace body and connected to the second support plate. The second driving member drives the first lifting rod to rise and fall and drives the second support plate to rise and fall, so that the insulation device and the metal crucible are lifted and lowered synchronously.

10. The apparatus for growing gallium oxide crystals according to claim 5 or 6, characterized in that The crystal growth equipment includes a third lifting device, which includes a third driving member and a second lifting rod connected to the third driving member. The third driving member is placed outside the furnace body, one end of the second lifting rod is connected to the third driving member, and the other end of the second lifting rod is connected to the induction coil. The third driving member drives the second lifting rod to rise and fall and drives the induction coil to rise and fall synchronously.

11. The apparatus for growing gallium oxide crystals according to claim 7, wherein: The crystal growth equipment includes a fourth lifting device, which includes a fourth driving member and a third lifting rod connected to the fourth driving member. The fourth driving member is placed outside the furnace body, one end of the third lifting rod is connected to the fourth driving member, and the other end of the third lifting rod is connected to the resistance heater. The fourth driving member drives the third lifting rod to rise and fall and drives the resistance heater to rise and fall synchronously.

12. A method for growing gallium oxide crystals using a slow cooling method, using the apparatus for growing gallium oxide crystals according to any one of claims 5 to 9, wherein the apparatus for growing gallium oxide crystals comprises a first lifting device or a second lifting device, characterized in that: At least the following steps are included: Adjusting the position of the metal crucible along the height direction of the gallium oxide crystal growing device by the first lifting device or the second lifting device so that the half-height line position of the metal crucible is flush with the half-height line position of the induction coil or is higher than the half-height line position of the induction coil; heating the gallium oxide raw material in the metal crucible at a first preset power until it is completely melted and generates some steam, wherein the steam condenses on the inner surface of the crucible cover, flows along the inner wall of the crucible cover to the contact point between the crucible cover and the crucible body, and climbs to the outside of the crucible cover at the contact point to cool and solidify, thereby sealing the crucible; The temperature is kept constant for a certain period of time, and then the heating power is slowly reduced, so that the raw material at the bottom of the metal crucible begins to crystallize and gradually grows toward the crucible cover, so that the raw material in the entire crucible grows into gallium oxide crystals.

13. A method for growing gallium oxide crystals using a zone melting method, using the apparatus for growing gallium oxide crystals according to any one of claims 5 to 9, wherein the apparatus for growing gallium oxide crystals comprises a first lifting device or a second lifting device, characterized in that: At least the following steps are included: Adjusting the position of the metal crucible along the height direction of the device for growing gallium oxide crystals by a first lifting device or a second lifting device so that the bottom of the metal crucible is flush with the half-height line position of the induction coil; Melting the gallium oxide raw material within a certain thickness on the bottom surface of the metal crucible at a second preset power to generate some vapor, which condenses on the inner surface of the crucible lid and flows along the inner wall of the crucible lid to the contact point between the crucible lid and the crucible body, and then climbs to the outside of the crucible lid at the contact point to cool and solidify, thereby sealing the crucible; The metal crucible is adjusted to move downward by the first lifting device or the second lifting device, and the raw materials at a position flush with the half-height line of the induction coil are melted successively. The raw materials at the bottom of the metal crucible begin to crystallize and gradually grow toward the crucible cover, so that the raw materials in the entire crucible grow into gallium oxide crystals.

14. A method for growing gallium oxide crystals using a crucible descent method, comprising using the apparatus for growing gallium oxide crystals according to any one of claims 5 to 9, wherein the apparatus for growing gallium oxide crystals comprises a first lifting device or a second lifting device, wherein: At least the following steps are included: Adjusting the position of the metal crucible along the height direction of the device for growing gallium oxide crystals by the first lifting device or the second lifting device so that the bottom of the metal crucible is flush with or higher than the half-height line position of the induction coil; Melting all the gallium oxide raw material in the metal crucible at a third preset power to generate some steam, wherein the steam condenses on an inner surface of the crucible lid, flows along the inner wall of the crucible lid to a contact point between the crucible lid and the crucible body, and then climbs to the outside of the crucible lid at the contact point to cool and solidify, thereby sealing the crucible; The metal crucible is adjusted to move downward by the first lifting device or the second lifting device, and the raw material at the bottom of the metal crucible begins to crystallize and gradually grows toward the crucible cover, so that the raw material in the entire crucible grows into gallium oxide crystals.

15. The method for growing gallium oxide crystals according to any one of claims 12 to 14, characterized in that: After the crystal growth is completed, the following furnace annealing steps are also included: Adjusting the heating power to a preset power, wherein the preset power is lower than the power required to melt the gallium oxide crystal; Adjusting the position of the metal crucible by the first lifting device or the second lifting device so that the half-height line of the metal crucible is flush with or higher than the half-height line of the induction coil; Keep warm for not less than 10 hours at the preset power; The temperature was lowered to room temperature at a rate of no more than 50°C / hour.

16. The method for growing gallium oxide crystals according to claim 15, wherein: After furnace annealing, the following steps are also included: demoulding and crystal removal: Manually increase the heating power to the preset power within 1-10 seconds; Stabilize at the preset power for 1-10 minutes; The heating power is manually reduced to 0 within 1-10 seconds, and the difference in thermal expansion coefficient and temperature change speed between the metal crucible and the gallium oxide crystal is utilized to separate the crystal from the crucible wall and thus demold.

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