A multi-station crystal growth apparatus

Abstract

A multi-station crystal growth device, comprising a high-pressure vessel body (1) with flanges at the top and bottom ends, which are integrally formed; a furnace bottom base (17) fixed to the lower part of the high-pressure vessel body (1); at least two crystal furnaces (13) evenly distributed on the furnace bottom base (17) around the central axis of the high-pressure vessel body (1); each crystal furnace (13) is provided with an independent heating and cooling assembly; each crystal furnace (13) is provided with a crucible bracket (16), the bracket is connected to a transmission shaft, the transmission shaft penetrates through the high-pressure vessel bottom plate (26) and is connected to a motor (23), which drives the crucible to rotate; the high-pressure vessel base comprises a high-pressure vessel bottom plate (26) integrally formed with the base flange (21), the base is provided with a transmission shaft channel, the channel is provided with a magnetic fluid sealing structure (24), the base flange (21) bears the high-pressure static seal, and the magnetic fluid sealing structure (24) realizes the dynamic seal of the transmission shaft. The present application realizes the synchronous growth of multiple crystals in a single high-pressure vessel, and improves the efficiency and quality.

Description

Technical Field

[0001] This invention relates to the field of crystal growth equipment technology, and in particular to a multi-station crystal growth apparatus. Background Technology

[0002] High-pressure autoclave single crystal furnaces are core equipment for growing second-generation semiconductor crystals such as indium phosphide and gallium arsenide, as well as oxide crystals such as sapphire, gallium oxide, and spinel. They are widely used in semiconductor substrates, optical windows, and new energy materials. Traditional single crystal furnace equipment typically adopts a single-furnace-one-station structure, meaning that only one single crystal furnace is set up in a single autoclave furnace chamber, and only one crystal can be grown per batch. The heating and cooling systems are dedicated to a single furnace. This approach results in low batch capacity, making it difficult to support large-scale mass production needs, and incurs high land costs.

[0003] To increase production capacity, some existing technologies attempt to adopt a multi-station approach, which involves setting up multiple single-crystal furnaces within a single autoclave and sharing heating and cooling systems. However, this multi-station approach with shared systems presents the following technical problems.

[0004] First, there is mutual interference between the thermal fields of the furnaces. When multiple furnaces share the same heating and cooling system, the temperature field of each furnace is inconsistent and difficult to control independently, resulting in low crystal yield and poor batch stability.

[0005] Secondly, maintenance is inconvenient and downtime losses are significant. In existing equipment, water-cooling jackets and other components are mostly fixedly connected to the furnace body and cannot be disassembled independently. When the water-cooling jacket or heating element of a single furnace body fails, the entire furnace chamber must be disassembled or the machine shut down for repair, affecting the normal operation of other furnace bodies in the same chamber. This results in low equipment uptime and high maintenance costs.

[0006] Third, the crystal growth efficiency and crystal quality are insufficient. The crucibles of traditional equipment are mostly placed statically, resulting in poor melt convection stability, which easily leads to temperature stratification and compositional segregation. This results in high dislocation density, numerous internal defects, and long crystal growth cycles during the crystal growth process.

[0007] Fourth, the reliability of high-pressure dynamic seals is poor. In the environment of a high-pressure reactor, a reliable dynamic seal is required at the point where the drive shaft passes through the bottom plate of the reactor body. Traditional packing seals or mechanical seals are prone to wear, aging, and leakage under high temperature and pressure conditions, which not only disrupts the pressure stability inside the furnace but also poses safety hazards. At the same time, the frictional resistance is relatively large, affecting the rotational stability of the drive shaft.

[0008] In addition, existing technologies include solutions for independent lifting and lowering of multiple workstations through a lowering mechanism, solutions for fault compensation through operation monitoring methods, and solutions that employ physical vapor transport methods and incorporate crucible rotation. However, none of these solutions simultaneously address the aforementioned issues in multi-station parallel production, such as independent control of the thermal field, modular equipment maintenance, uniform heating during crucible rotation, and reliability of high-pressure dynamic seals.

[0009] In summary, the existing technology lacks a comprehensive technical solution that can simultaneously address multiple issues such as multi-station parallel production, independent thermal field control, modular equipment maintenance, crucible rotation for uniform heating, and high-pressure dynamic seal reliability. Summary of the Invention

[0010] The purpose of this invention is to provide a multi-station crystal growth device. This device utilizes a multi-station layout evenly distributed around the central axis of the autoclave, an independent temperature and cooling modular structure, a crucible rotation and homogenization mechanism, and a synergistic pressure-bearing and sealing system of magnetic fluid and base flange. This enables the simultaneous growth of multiple crystals within a single autoclave, solving problems such as mutual interference of thermal fields between multiple stations, inconvenient maintenance, low crystal growth efficiency, and poor reliability of high-pressure dynamic seals. The device achieves parallel production of multiple stations within a single furnace, independent temperature and cooling control for each furnace, modular design for easy maintenance, and high sealing reliability, thereby improving production efficiency and crystal quality, reducing operating costs, and adapting to the needs of large-scale mass production.

[0011] To address the aforementioned problems, a first aspect of the present invention provides a multi-station crystal growth apparatus, characterized in that the multi-station crystal growth apparatus comprises: a high-pressure vessel body 1, which is a sealed high-pressure container; a top flange 18 is provided at its top for sealing with the high-pressure vessel cover 11; a bottom flange 19 is provided at its bottom for connecting with the high-pressure vessel base; the high-pressure vessel body 1, the top flange 18, and the bottom flange 19 are integrally formed; a furnace bottom base 17 is fixedly installed inside the lower part of the high-pressure vessel body 1; at least two crystal furnaces 13 are evenly distributed around the central axis of the high-pressure vessel body 1 on the furnace bottom base 17; each crystal furnace 13 is equipped with a heating group. The system includes components and cooling assemblies; each crystal furnace 13 has a crucible support 16 inside, and the crucible support 16 is connected to a drive shaft; the pressure vessel base includes a pressure vessel bottom plate 26 and a base flange 21, the base flange 21 is located below the pressure vessel bottom plate 26, the pressure vessel bottom plate 26 and the base flange 21 are integrally formed, the pressure vessel bottom plate 26 is provided with a drive shaft channel, the drive shaft channel is provided with a magnetic fluid sealing structure 24, the drive shaft passes through the drive shaft channel and is connected to a motor 23 for driving the crucible to rotate; wherein, the base flange 21 is used to bear the high-pressure static seal of the pressure vessel body, and the magnetic fluid sealing structure 24 is used to achieve dynamic sealing when the drive shaft is rotating.

[0012] This invention achieves simultaneous growth of multiple crystals within a single high-pressure reactor by fixing a furnace bottom base inside the reactor body and evenly distributing at least two crystal furnaces around the central axis of the reactor body on the furnace bottom base. Each crystal furnace is equipped with an independent heating and cooling component, allowing each furnace to independently control its thermal field and avoiding mutual interference between the thermal fields of multiple workstations. Each crystal furnace has a crucible support frame connected to a drive shaft, which passes through the bottom plate of the reactor body and is connected to a motor to drive the crucible to rotate during crystal growth, thereby optimizing the melt convection state, eliminating temperature stratification and compositional segregation, and shortening the crystal growth cycle. The bottom plate of the reactor body has a channel for the drive shaft to pass through. The base flange and the magnetic fluid sealing structure form a collaborative pressure-bearing sealing system, where the base flange is used to provide a high-pressure static seal for the reactor body, and the magnetic fluid sealing structure is used to achieve a dynamic seal when the drive shaft is rotating. This invention, through the synergistic design of the aforementioned multi-station layout, independent temperature and cooling control, crucible rotation for uniform heating, and graded pressure-bearing sealing, fundamentally solves the technical problems in the prior art, such as low single-station capacity of a single furnace, mutual interference of thermal fields in multiple stations, low crystal growth efficiency due to static placement of crucibles, and poor reliability of high-pressure dynamic seals. It significantly improves production efficiency, crystal quality, equipment uptime, and operational stability.

[0013] Furthermore, the multi-station crystal growth apparatus also includes: at least two flow-blocking circular plates 27, which are spaced apart in the inner cavity of the autoclave body 1. Each flow-blocking circular plate 27 has a furnace body clearance through hole corresponding to each crystal furnace 13, and each crystal furnace 13 passes through the furnace body clearance through hole.

[0014] Furthermore, the multi-station crystal growth apparatus also includes: multiple layers of reflective heat insulation plates, which are spaced apart below the crucible support 16 and above the furnace bottom of the crystal furnace 13. Each layer of reflective heat insulation plate is coaxially arranged with the corresponding crystal furnace 13, and a drive shaft through hole is opened in the center of each layer of reflective heat insulation plate.

[0015] Furthermore, a heat insulation structure is provided between each crystal furnace 13, the heat insulation structure including at least one of a reflective cylinder, a heat radiation shielding layer, or a heat insulation baffle.

[0016] Furthermore, the furnace base 17 has a disc-shaped structure, and the plate of the furnace base 17 is provided with mounting stops corresponding to each crystal furnace 13; the lower end cylinder of each crystal furnace 13 is provided with a mounting flange, and each crystal furnace 13 is seated in the mounting stop. A high-temperature resistant sealing and heat-insulating gasket is provided between the mounting flange and the furnace base 17, and they are detachably fixedly connected by fasteners.

[0017] Furthermore, the cooling component is a water-cooled jacket 15, which is detachably fitted onto the outside of the crystal furnace 13; an annular gap is reserved between the water-cooled jacket 15 and the inner wall of the autoclave body 1.

[0018] Furthermore, each crystal furnace 13 is equipped with a cooling pipe for supplying water to the water-cooled jacket 15. The cooling pipe runs vertically through the furnace bottom base 17 and the autoclave bottom plate 26. A high-temperature resistant heat-insulating sleeve is fitted between the cooling pipe and the furnace bottom base 17. A flange-type through-wall sealing joint is provided at the position where the cooling pipe exits the autoclave bottom plate 26. The annular gap between the high-temperature resistant heat-insulating sleeve and the cooling pipe is filled with high-temperature resistant sealing filler.

[0019] Furthermore, the heating component is a heating wire, which is spirally arranged around the inner wall of each crystal furnace 13, and a heat insulation layer is provided between the heating wire and the inner wall of each crystal furnace 13.

[0020] Furthermore, an annular support seat is provided on the lower inner wall of the autoclave body 1, and an annular support flange is provided on the outer edge of the furnace bottom base 17. The furnace bottom base 17 is integrally seated on the annular support seat through the annular support flange and is detachably fixed by fasteners. A high-temperature resistant heat insulation gasket is provided between the furnace bottom base 17 and the annular support seat.

[0021] Furthermore, the high-pressure autoclave bottom plate 26 is provided with the drive shaft channel corresponding to the center of each crystal furnace 13. The magnetic fluid sealing structure 24 is coaxially fixed to the lower side of the base flange 21. The drive shaft passes through the inner hole of the magnetic fluid sealing structure 24 and the drive shaft channel from bottom to top and is then connected to the crucible support 16.

[0022] Furthermore, the multi-station crystal growth apparatus also includes an autoclave cover 11, which is provided with a double sealing structure 14. The double sealing structure 14 includes an end face sealing groove 141 and an axial sealing groove 142. The axial sealing groove 142 is formed on the inner cylindrical wall of the autoclave cover 11 and a sealing ring is provided therein. The end face sealing groove 141 is formed on the upper end face of the top flange 18 and a sealing gasket is provided therein.

[0023] Furthermore, the rotation speed of the crucible support 16 can be adjusted according to the state of the crystal raw material and / or the temperature data collected in real time; the crucible support 16 can rotate forward, reverse, or switch between forward and reverse rotation.

[0024] The above-described technical solution of the present invention has the following beneficial technical effects: 1. Significantly increased single-batch capacity to meet the demands of large-scale mass production: By evenly distributing at least two crystal furnaces around the central axis within a single autoclave, the limitation of traditional single-furnace, single-station, single-batch growth of only one crystal is overcome, enabling the simultaneous growth of multiple crystals and multiplying the single-batch capacity. Simultaneously, the sharing of the same autoclave body by multiple stations reduces equipment footprint and lowers land costs, fully meeting the application requirements of large-scale mass production of crystal materials.

[0025] 2. Eliminating inter-furnace thermal interference to ensure crystal consistency and yield: Each crystal furnace is equipped with independent heating and cooling components, combined with thermal insulation structures such as reflective cylinders, heat radiation shielding layers, or heat insulation baffles between workstations, completely decoupling the thermal field coupling caused by the shared heating and cooling systems in traditional multi-workstation solutions. The thermal field of each crystal furnace can be independently controlled without interference, avoiding thermal crosstalk between multiple furnaces, significantly improving the consistency and stability of the temperature field at each workstation, thereby greatly improving the batch stability and yield of crystals.

[0026] 3. Modular design facilitates easy maintenance and significantly improves equipment uptime: The water-cooling jacket and crystal furnace body are connected by a modular design that allows for independent disassembly and assembly. Cooling pipes extend independently through the autoclave bottom plate via flanged through-wall sealing joints. When a single crystal furnace's water-cooling jacket or heating element malfunctions, that station can be disassembled for repair or replacement without requiring complete furnace disassembly or shutdown, thus not affecting the normal operation of other stations. Simultaneously, the furnace bottom base rests on a ring-shaped support seat via a ring-shaped support flange and is detachably connected with fasteners. The entire module can be hoisted in and out, significantly shortening maintenance time, reducing operating costs, and substantially improving the overall equipment uptime.

[0027] 4. Optimized melt convection for improved crystal growth efficiency and quality: Each crystal furnace is equipped with a rotatable crucible support, driven by an independent motor via a drive shaft, ensuring continuous crucible rotation during crystal growth. This crucible rotation forces convection within the melt, breaking down the boundary layer of natural convection, homogenizing the melt temperature and solute concentration fields, and flushing the solid-liquid growth interface. This effectively eliminates temperature stratification and compositional segregation, reducing crystal defects such as bubbles, dislocations, inclusions, and cracks. This design shortens the crystal growth cycle and significantly improves crystal integrity and optical homogeneity.

[0028] 5. Improve the reliability and stability of high-pressure dynamic seals: A pressure-bearing sealing system is formed at the drive shaft channel of the autoclave bottom plate, consisting of a base flange and a magnetic fluid sealing structure. The base flange provides a high-pressure static seal for the autoclave body, while the magnetic fluid sealing structure utilizes a magnetic field to confine the magnetic fluid, creating a multi-stage liquid sealing barrier that seals only the residual low pressure in the bottom buffer chamber, achieving a low-friction, zero-leakage dynamic seal during drive shaft rotation. This staged pressure-bearing design effectively prevents leakage of high-temperature, high-pressure media, ensuring stable pressure within the furnace, and is suitable for long-term uniform crucible rotation, significantly improving equipment safety and operational stability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a multi-station crystal growth apparatus according to an embodiment of the present invention; Figure 2 This is a partially enlarged schematic diagram of the flow-blocking circular plate in an embodiment of the present invention; Figure 3 This is a partially enlarged schematic diagram of the double sealing structure in the top cover of the autoclave.

[0030] Figure label: 1: Autoclave body; 11: Autoclave top cover; 13: Crystal furnace; 14: Double sealing structure; 141: End face sealing groove; 142: Axial sealing groove; 15: Water cooling jacket; 16: Crucible support; 17: Furnace bottom base; 18: Top flange; 19: Bottom flange; 21: Base flange; 22: Motor base; 23: Motor; 24: Magnetohydrodynamic sealing structure; 25: Coupling; 26: Autoclave bottom plate; 27: Flow-restricting circular plate. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0032] The following is combined Figure 1 and Figure 2 The multi-station crystal growth apparatus provided by the present invention will be described.

[0033] Figure 1 This is a schematic diagram of the structure of a multi-station crystal growth apparatus according to an embodiment of the present invention.

[0034] like Figure 1As shown, the multi-station crystal growth apparatus of this embodiment includes an autoclave body 1, a furnace bottom base 17, at least two crystal furnaces 13, each crystal furnace 13 is equipped with an independent heating component and a cooling component, as well as a corresponding transmission and sealing structure.

[0035] The autoclave body 1 is a sealed high-pressure vessel. It has a top flange 18 at its top for sealing with the autoclave cover 11; and a bottom flange 19 at its bottom for connecting to the autoclave base. The autoclave body 1, top flange 18, and bottom flange 19 are integrally formed. Preferably, the cylinder of the autoclave body 1 is made of S316 seamless steel pipe, and the top flange cover 18 and bottom flange 19 are made of 316 forgings. The rated working pressure of the autoclave body 1 is 8 MPa, the design pressure is 10 MPa, the maximum working temperature of the autoclave furnace is 1150℃, and the isothermal range for crystal growth is 1060~1080℃.

[0036] The furnace bottom base 17 is fixedly installed inside the lower part of the autoclave body 1. The furnace bottom base 17 has a disc-shaped structure, and the plate of the furnace bottom base 17 is provided with mounting stops corresponding to each crystal furnace 13. Preferably, the furnace bottom base 17 is a disc-shaped integral forging structure, made of 316L stainless steel, and the base plate is machined with recessed positioning mounting stops corresponding to each crystal furnace 13. A drive shaft through hole and a cooling water pipe through hole are reserved in the center of each mounting stop.

[0037] An annular support seat is installed on the lower inner wall of the autoclave body 1, and an annular support flange is installed on the outer edge of the furnace bottom base 17. The furnace bottom base 17 is integrally seated on the annular support seat via the annular support flange and is detachably fixed by fasteners. A high-temperature resistant heat-insulating gasket is installed between the furnace bottom base 17 and the annular support seat to reduce heat conduction from the base to the side wall of the autoclave body. The furnace bottom base 17 is only locked by the annular support seat on the inner wall of the autoclave body and does not have rigid contact with the autoclave, which reduces heat transfer and ensures coaxiality and support rigidity for multi-station installation. Because the furnace bottom base 17 adopts an integral forging structure and can be detachably connected by fasteners, the entire module can be hoisted in and out, greatly shortening maintenance time and improving the overall uptime of the equipment.

[0038] At least two crystal furnaces 13 are evenly distributed around the central axis of the autoclave body 1 on the furnace base 17. Preferably, the main body of the crystal furnace 13 is made of 316L stainless steel. The number of crystal furnaces 13 can be two, three, or four. When there are two, they are symmetrically distributed; when there are three, they are distributed in an equilateral triangle; and when there are four, they are distributed in a cross-shaped symmetrical arrangement. A heat insulation structure is provided between each crystal furnace 13, which includes at least one of a reflector, a heat radiation shielding layer, or a heat insulation baffle. Preferably, each crystal furnace 13 is equipped with an independent multi-layer reflector to form a closed thermal field unit. Through the multi-station layout, the limitation of traditional single-furnace single-station single-batch growth of only one crystal is broken, realizing the synchronous growth of multiple crystals, doubling the single-batch capacity. At the same time, sharing the same autoclave body reduces the equipment footprint and adapts to the needs of large-scale mass production. The heat insulation structures such as reflectors and heat insulation baffles enable each crystal furnace to form a closed thermal field unit. When a single crystal furnace fails to cool down or abnormally heats up, the heat will not be quickly transferred to adjacent workstations, thus avoiding interference with the thermal field stability of other crystal furnaces. Together with the heat insulation reflectors and heat insulation baffles between workstations, electrical, thermal field and pressure isolation of each workstation is achieved.

[0039] In one specific embodiment, there are three crystal furnaces 13, which are evenly distributed in an equilateral triangle around the central axis of the autoclave body 1, with an included angle of 120 degrees between adjacent furnaces. The motors 23, couplings 25, and drive shafts of the three crystal furnaces are completely independent, and the transmission systems of each station are not interconnected. When a single motor fails, only the crucible at that station stops rotating; the crucible rotation process at the other two stations remains unaffected and can continue to operate according to the set program. Simultaneously, the heating and cooling systems of the three crystal furnaces are also independent. If the heating wire of a single crystal furnace melts or the water-cooling jacket leaks, that station can be shut down independently without affecting the normal operation of other equipment. This multi-station independent layout design achieves simultaneous growth of multiple crystals and ensures fault isolation between stations, significantly improving the overall uptime and process stability of the equipment.

[0040] Each crystal furnace 13 has a mounting flange at its lower end, and each crystal furnace 13 sits within the mounting stop. A high-temperature resistant sealing and heat-insulating gasket is provided between the mounting flange and the furnace base 17, and they are detachably fixed together by fasteners. Preferably, a positioning outer circle is set on the lower outer wall of the crystal furnace, and a positioning stop is correspondingly opened on the furnace base to form a positioning inner hole. The positioning outer circle and the positioning inner hole are coaxially fitted with a small clearance (for example, the positioning outer circle and the positioning inner hole are fitted with a small clearance coaxially with an H7 / h6 clearance, and the clearance on one side is controlled within 0.10 to 0.20 mm). The insertion port is provided with a guide chamfer to facilitate hoisting and alignment. Relying on the precision insertion, the crystal furnace is automatically centered radially and limited circumferentially, ensuring the distribution accuracy and coaxiality of multiple crystal furnaces. There is no relative slippage or tilting misalignment among the crystal furnaces, and the overall structure has strong stability. The high-temperature resistant graphite sealing and heat-insulating gasket laid between the mounting flange and the base not only ensures a tight seal and blocks the downward conduction of heat, but also avoids thermal bridges caused by rigid metal contact.

[0041] The heating element is a heating wire, which is arranged along the inner wall of each crystal furnace 13. Preferably, the heating wire is spirally wound, continuously spirally wound outwards from the inner wall of each crystal furnace 13, and a certain heat insulation gap is reserved between the heating wire and the inner wall of each crystal furnace 13 for placing the heat insulation layer. The heating wire does not directly contact the inner wall of each crystal furnace 13. Each heating wire is connected to an independent power supply circuit, and the heating power can be adjusted individually according to the process requirements of a single furnace, realizing independent control of the thermal field of each crystal furnace and avoiding mutual interference between the thermal fields of multiple workstations. The heating wire can also be divided into multiple segments, with segmented temperature control to meet the multi-temperature zone requirements within a single crystal furnace. The heating system is independently controlled, with each crystal furnace equipped with an independent heating power supply and temperature control module. If the heating wire of a single furnace melts or the temperature control fails, only that circuit trips and cuts off the power, and the heating systems of other crystal furnaces are unaffected and can continue to operate according to the set process. This independent temperature control design, combined with the insulation structure between workstations, can significantly reduce the temperature difference between furnaces and improve the consistency and stability of the temperature field at each workstation, thereby greatly improving the batch stability and yield of crystals. The cooling component is a water-cooled jacket 15, which is detachably fitted onto the outside of the crystal furnace 13. An annular gap is reserved between the water-cooled jacket 15 and the inner wall of the autoclave body 1. Preferably, the water-cooled jacket 15 is made of 316L stainless steel, with a uniform annular gap of 30 mm on one side. This gap meets the thermal expansion margin of the water-cooled jacket and the furnace body structure under high-temperature conditions, effectively blocks thermal crosstalk between workstations, balances the temperature field distribution in the furnace, and at the same time provides operating space for independent disassembly and assembly of the water-cooled jacket and hoisting and maintenance of the crystal furnace. The structure is compact, heat-insulating, easy to assemble, and safe. The water-cooled jacket and the crystal furnace body adopt a modular connection method, which can be independently disassembled and assembled, and each water-cooled jacket is connected to an independent cooling water circuit.

[0042] Each crystal furnace 13 is equipped with a cooling pipe for supplying water to the water-cooling jacket 15. The cooling pipe runs vertically through the furnace bottom base 17 and the autoclave bottom plate 26. A high-temperature resistant heat-insulating sleeve is fitted between the cooling pipe and the furnace bottom base 17. The base has a pre-set large-diameter through hole, with the hole diameter being 8-12 mm larger than the outer diameter of the cooling pipe. A flange-type through-wall sealing joint is installed at the position where the cooling pipe exits the autoclave bottom plate 26. The annular gap between the high-temperature resistant heat-insulating sleeve and the cooling pipe is filled with high-temperature resistant sealing filler. Preferably, the high-temperature resistant sealing filler is a flexible high-temperature resistant graphite sealing filler, with a small amount of removable high-temperature resistant inorganic sealant applied to the outside for auxiliary fixation, achieving furnace atmosphere sealing and heat insulation. The water cooling system has independent branches. Each crystal furnace's water-cooling jacket is equipped with independent inlet and outlet water branches, flow switches, and temperature sensors. If the water circuit of a single furnace is blocked or leaks, the branch can be automatically shut off without affecting the cooling water circulation of other crystal furnaces, preventing the cooling of the entire furnace from failing. This modular water circuit design allows each cooling water circuit to operate independently, enabling individual disassembly and maintenance without affecting the overall structural stability of other workstations and the base. When a single crystal furnace's water-cooling jacket or heating element fails, that workstation can be disassembled for repair without requiring a complete shutdown, significantly improving equipment uptime and reducing maintenance costs.

[0043] In one specific embodiment, the autoclave is filled with 6.6MPa high-pressure argon protective gas, while the cooling pipes flow with normal-pressure cooling water. This creates a huge internal and external pressure difference of up to 6MPa across the pipe walls. The outer side of the pipe is subjected to 6MPa high pressure squeezing inwards, while the inner side is only at normal pressure. If conventional water pipes were used, the pipes would easily become unstable and dented or the pipe walls would collapse under such a huge external pressure load. Therefore, the entire cylinder of the water-cooled jacket 15 and the inlet and outlet water cooling pipes are uniformly made of seamless 316L austenitic stainless steel, abandoning ordinary 304 stainless steel, to ensure sufficient structural strength against external pressure. The inner diameter of a single cooling pipe is fixed at 10mm, with a single-sided wall thickness of 2mm, and the critical external pressure instability pressure is checked to be >12MPa. The annular water cavity of the water-cooled jacket 15 has a flow rate matching the required flow of the matching water circuit, avoiding the use of a large-diameter, thin-walled structure. The 10mm inner diameter can meet the rated flow rate of 12L / min for a single cooling water channel. The water flow velocity is moderate and the heat exchange is sufficient. The pipe diameter is minimized as much as possible while ensuring cooling and heat exchange performance, taking into account both heat exchange efficiency and structural rigidity against external pressure.

[0044] Each crystal furnace 13 is equipped with a crucible support 16, which is connected to a drive shaft. The drive shaft passes through the autoclave bottom plate 26 and is connected to a motor 23, used to drive the crucible to rotate during crystal growth. A motor base 22 is located below the autoclave base, and the motor 23 is fixedly installed below the motor base 22. The motor base 22 is used to install and position the motor 23, ensuring the coaxiality of the motor 23 and the drive shaft. The output end of the motor 23 is connected to the drive shaft via a coupling 25, which is used to transmit torque and compensate for installation misalignment between the motor 23 output shaft and the drive shaft. The drive shaft passes through the inner hole of the magnetohydrodynamic sealing structure 24 and the drive shaft channel from bottom to top before connecting to the crucible support 16. An annular buffer pressure relief gap is formed between the inner hole of the base flange 21 and the drive shaft, which constitutes a sealed buffer cavity. After the high-pressure medium (e.g., 6.6 MPa) in the furnace is slowly depressurized through the tiny gap in the flange inner hole, the buffer chamber is stably maintained at a low-pressure environment of 0.1 to 0.3 MPa. The magnetic fluid sealing structure 24 only needs to dynamically seal the low-pressure medium in the buffer chamber, completely avoiding the direct impact of the main high pressure (e.g., 6.6 MPa), thereby realizing the graded pressure bearing of static pressure bearing of the base flange and dynamic pressure bearing of magnetic fluid low pressure seal.

[0045] Preferably, the crucible support 16 is made of 316L stainless steel, and the drive shaft is made of GH4169 nickel-based high-temperature alloy. The crucible support 16 and the drive shaft are connected by a hexagonal positioning plug-in structure. The autoclave reflector can reflect a large amount of heat, and the drive shaft has poor thermal conductivity, so it will not cause the motor to overheat and be damaged.

[0046] In some embodiments, the multi-station crystal growth apparatus further includes multiple layers of reflective heat insulation plates. These reflective heat insulation plates are vertically spaced below the crucible support 16 and above the furnace bottom of the crystal furnace 13. Each layer of reflective heat insulation plate is coaxially arranged with the corresponding crystal furnace 13. A drive shaft through hole is provided at the center of each layer of reflective heat insulation plate, and a uniform axial heat insulation gap is reserved between adjacent layers. Preferably, the multiple layers of reflective heat insulation plates are made of high-temperature resistant GH4169 nickel-based alloy sheet with a thickness of 2 mm. Both the upper and lower surfaces of the reflective heat insulation plates are mirror-polished, with a surface roughness Ra≤0.8μm and a high-temperature infrared thermal radiation reflectivity ≥92%. This allows for efficient mirror reflection of long-wave thermal radiation at 1070℃, reflecting most of the downward-transmitted thermal radiation back to the furnace heating zone. GH4169 material can withstand high temperatures of 1070℃ for a long time. It will not oxidize or undergo high-temperature creep and warping deformation under high pressure, ensuring that the multi-layer reflective heat insulation panel maintains a flat mirror state for a long time and continuously and stably plays a role in radiation blocking.

[0047] The rotation speed of the crucible support 16 can be adjusted according to the state of the crystal raw material and / or the real-time temperature data. The crucible support 16 can rotate forward, backward, or switch between forward and reverse rotation. Specifically, the rotation speed of the crucible support 16 can automatically switch or stop according to the needs of crystal growth. The rotation of the crucible support 16 supports forward, backward, or reverse rotation switching and has an automatic control function linked to temperature, which can automatically adjust the rotation speed according to the real-time temperature data. Preferably, the adjustable speed range is 5 to 30 revolutions per minute, with stepless speed regulation capability, supporting both manual setting via human-machine interface and automatic program control modes. The equipment has a built-in programmable controller, which can pre-enter the corresponding rotation speed parameters for each process segment and automatically switch the rotation speed according to the growth process without manual intervention. In other embodiments, the rotation direction can be switched manually or by program command according to the crystal growth process requirements to meet the requirements of different crystal forms and melt convection conditions. The system collects furnace temperature and melt temperature data in real time. When the temperature deviates from the process threshold, the program automatically matches and adjusts the crucible rotation speed.

[0048] The rotation of the crucible forces convection in the internal melt, breaking the natural convection boundary layer, homogenizing the melt temperature and solute concentration fields, scouring the solid-liquid growth interface, reducing local undercooling and component segregation, and decreasing defects such as bubbles, dislocations, inclusions, and cracks, thus improving the integrity and optical homogeneity of single crystals. High-temperature melts originally rely on temperature differences for natural convection, resulting in turbulent flow rates and irregular flow directions, easily leading to localized high and low temperature zones. The crucible rotation causes the melt to follow in a circular swirling flow, forming a regular axisymmetric flow field and eliminating dead zones and stagnant areas. Continuous heat exchange by the rotating fluid significantly reduces the radial and axial temperature differences within the furnace, resulting in a smooth and regular solid-liquid growth interface morphology, avoiding distorted growth and reducing twinning and impurity crystal formation from the source. Different elemental compositions have varying densities; in a static melt, heavier components tend to sink while lighter components float and stratify. The rotational shear force promotes uniform diffusion and transport of the solute, ensuring consistent component proportions in each region and uniform axial and radial composition distribution in the crystal. Indium phosphide melt has good fluidity, but the phosphorus component is easily volatilized and lost at high temperatures. By rotating the crucible at a constant speed, a stable axisymmetric swirling flow can be formed, which can suppress the local enrichment / deficiency of phosphorus elements, avoid dislocations and twins caused by component imbalance, and ensure that the radial and axial phosphorus-indium ratio is uniform throughout the crystal.

[0049] This design can shorten the crystal growth cycle, reduce the crystal dislocation density, and significantly improve crystal growth efficiency and crystal quality.

[0050] The autoclave base includes an autoclave base plate 26 and a base flange 21. The base flange 21 is located below the autoclave base plate 26, and the autoclave base plate 26 and the base flange 21 are integrally formed. A drive shaft channel or through hole is provided on the autoclave base plate 26 corresponding to the center of each crystal furnace 13. A magnetic fluid sealing structure 24 is provided at the drive shaft channel. The magnetic fluid sealing structure 24 is coaxially fixed to the lower side of the base flange 21. The drive shaft passes through the drive shaft channel or through hole and is connected to the motor 23 to drive the crucible to rotate. The base flange 21 is used to provide a high-pressure static seal for the autoclave body, while the magnetic fluid sealing structure 24 is used to achieve a dynamic seal during drive shaft rotation.

[0051] In some embodiments, the base flange 21 has two independent types of NPT tapered thread feed holes evenly distributed circumferentially on its disc surface. These holes employ 1 / 2NPT and 3 / 4NPT tapered thread sealing structures, respectively, to arrange thermocouple feed holes and high-power electrode feed holes in separate zones. High-pressure leakage-free wire threading is achieved by relying on the self-tightening seal of the tapered thread. The two thread specifications are also differentiated to adapt to different cable diameters and current-carrying requirements. Specifically, the 1 / 2NPT internal tapered thread feed hole is dedicated to feeding in K-type high-temperature thermocouple leads. Each hole is adapted to the outer diameter of a single thermocouple sheath. The thread diameter is small, and the sealing volume is compact. Three to six groups are evenly distributed circumferentially on a single flange, corresponding to the upper, middle, and lower temperature measurement points of each crystal furnace 13, respectively, independently collecting temperature data for three temperature zones without interference. The 3 / 4NPT internal tapered thread feed hole is specially designed for feeding high-power electrodes into the heating assembly. The heating electrodes have a large current carrying capacity and a larger outer diameter of the electrode ceramic protective sleeve. A larger specification 3 / 4NPT tapered thread is selected to provide sufficient space for installation. Each station is equipped with two sets of 3 / 4NPT threaded holes, which are connected to the positive and negative heating electrodes respectively to meet the conductive installation requirements of a single furnace with a constant temperature heating power of 28kW.

[0052] Preferably, the base flange 21 adopts a tapered pipe thread static seal, which is responsible for the overall high-pressure sealing and pressure maintenance of the vessel body and is the core pressure-bearing sealing structure. The magnetic fluid sealing structure 24 uses fluorinated oil-based high-temperature magnetic fluid as a dynamic sealing medium. It does not directly bear the high pressure of the vessel body. Relying on the step-by-step pressure reduction gradient inside the vessel, it only seals the residual low pressure in the bottom buffer cavity, realizing zero-wear and low-friction dynamic sealing under the state of drive shaft rotation, which is suitable for the long-term uniform speed rotation of the crucible.

[0053] In some embodiments, the bottom flange 19 is fixedly connected to the autoclave base by bolts, and the base flange 21 is located below the bottom flange 19. The two fit tightly together to achieve an overall seal at the bottom of the autoclave. The base flange 21 is integrally formed from a 316 stainless steel forging. After being blocked by a multi-layer reflective heat insulation plate at the bottom, the operating temperature of the base flange 21 is stable below 300℃. The material is fully adaptable to the requirements of pressure bearing and resistance to phosphorus vapor corrosion. A coaxial through hole for the drive shaft is opened in the center of the base flange 21. The upper end face is a planar sealing pressure bearing surface, and the lower end face is a magnetic fluid seal installation positioning reference surface. Bolt mounting holes are evenly distributed around the outer edge of the flange. A coaxial annular positioning stop is machined on the lower end face of the base flange 21. The outer shell of the magnetic fluid seal structure 24 is integrally embedded in this positioning stop to achieve high-precision coaxial positioning with a coaxiality error ≤0.02mm. This stop restricts the radial displacement of the magnetic fluid seal structure 24, ensuring that the drive shaft, magnetic circuit, and flange are coaxial and preventing the drive shaft from rotating eccentrically and tearing the magnetic fluid seal film. The lower end of the flange is secured to the housing of the magnetic fluid sealing structure 24 by circumferential bolts. An O-ring is added to the contact surface between the flange and the magnetic fluid housing to achieve secondary sealing and prevent low-pressure gas from leaking out of the buffer chamber. An annular throttling slit is formed between the drive shaft and the central through-hole of the base flange 21. The radial clearance on one side of the slit is 0.28 mm, and the axial length of the throttling section is 25 mm. The flange inner hole adopts H7 tolerance and the drive shaft outer circle adopts h6 tolerance for precision fit to ensure uniform clearance throughout the entire ring.

[0054] The magnetofluid sealing structure 24 includes a magnetically conductive shaft, a permanent magnet, magnetically conductive pole shoes, and a magnetofluid medium. A multi-stage sealing gap is formed between the magnetically conductive pole shoes and the magnetically conductive shaft. Under the influence of a magnetic field, the magnetofluid medium fills the sealing gap to form a liquid sealing ring. Preferably, the magnetofluid sealing structure 24 also includes a non-magnetically conductive housing and bearings, which together form a closed magnetic circuit and a multi-stage liquid sealing barrier. The magnetically conductive shaft and pole shoes form a uniform sealing gap of 0.05 to 0.5 mm. The permanent magnet is a ring-shaped permanent magnet, axially magnetized to provide a stable magnetic field and establish a closed magnetic circuit between the shaft and the pole shoes. The inner circle of the magnetically conductive pole shoes is machined with multi-stage pole teeth, with 3 to 12 stages, forming a high magnetic field gradient region between the pole teeth and the shaft. This allows the magnetofluid to form multi-stage liquid O-rings, with each stage capable of withstanding pressures of 0.05 to 0.2 MPa, and the multi-stage series connection increasing the pressure resistance. The non-magnetically conductive housing prevents magnetic short circuits, accommodates the permanent magnet, pole shoes, and bearings, and provides an installation reference and protection. The bearing supports the rotating shaft, ensuring coaxiality and rotational accuracy, and maintaining a uniform sealing gap.

[0055] In this graded pressure-bearing sealing system, the base flange bears the main high-pressure load of the reactor body, while the magnetohydrodynamic seal only seals the residual low pressure in the bottom buffer chamber. Together, they form a high-precision, high-pressure-resistant dual-sealing structure. The static seal of the base flange and the magnetohydrodynamic seal work in tandem to ensure the overall pressure-bearing capacity of the autoclave while achieving a low-friction, zero-leakage dynamic seal under long-term rotation of the drive shaft. This design effectively prevents leakage of high-temperature, high-pressure media, ensures stable pressure within the furnace, and simultaneously minimizes frictional resistance, meeting the low-friction requirements of crucible rotation, significantly improving the safety and operational stability of the equipment.

[0056] The device also includes a high-pressure reactor cover 11, which has a double sealing structure 14, including an end face sealing groove 141 and an axial sealing groove 142. The axial sealing groove 142 is formed on the inner cylindrical wall of the high-pressure reactor cover 11, and a sealing ring is provided therein. The end face sealing groove 141 is formed on the upper end face of the top flange 18, and a sealing gasket is provided therein. Preferably, the axial sealing groove is a rectangular closed annular groove, and the sealing ring is made of high-temperature and high-pressure resistant fluororubber or metal-coated sealing ring. It adopts an embedded pre-installed installation, with the sealing ring completely embedded inside the annular groove, completely fitting the bottom and side walls of the groove. When assembling the reactor body, the coaxial insertion fit between the cover and the reactor body causes the sealing ring to be radially compressed and deformed, filling the tiny fit gap between the cylinder and the side wall of the cover, achieving circumferential radial sealing and limiting gas leakage along the radial gap. The end-face sealing groove adopts a trapezoidal sealing groove structure, with a slightly wider opening and a slightly narrower bottom, providing a limiting and anti-detachment function. This effectively constrains the deformation trajectory of the sealing gasket under pressure, preventing it from being squeezed outwards or experiencing localized pressure loss. The sealing gasket is installed flat and embedded. Under the uniform pre-tightening pressure of the top cover bolts, the gasket deforms axially under uniform pressure, completely filling the flange end-face contact gap and forming an axial high-pressure main sealing barrier, bearing the entire high-pressure sealing load of the vessel. This dual-seal structure employs two independent axial end-face seals, with two independent annular axial sealing grooves coaxially formed radially from the inside to the outside. These are the inner main sealing groove and the outer auxiliary sealing groove. The two sealing grooves are arranged in parallel, concentrically aligned, and not interconnected, forming a double-layer axial superimposed sealing structure. Compared to a single-seal structure, this structure offers advantages such as stronger pressure bearing capacity, higher leakage prevention redundancy, and better stability under high-temperature and high-pressure conditions.

[0057] The following describes the complete process flow of the multi-station crystal growth apparatus in this embodiment, with specific process parameters. In the loading and assembly stage, the seed crystal, polycrystalline raw materials, and liquid sealant are loaded into the crucible and placed on the crucible support 16. The crystal furnace 13 is positioned and inserted into the furnace bottom base, and the entire assembly is hoisted into the autoclave, completing the sealing assembly of the autoclave. In the vacuuming and gas filling stage, the furnace chamber is pre-vacuumed to a predetermined vacuum level, and high-purity argon gas is introduced and pressurized to the rated pressure. A pressure test is performed to ensure no leakage (e.g., the furnace chamber is pre-vacuumed to ≤5×10⁻⁶). -5(The pressure is stabilized at 8 MPa by filling with high-purity argon gas). During the gradient heating stage, each crystal furnace is heated at full power until the melt temperature range is reached, then switched to constant power for stable holding (e.g., each crystal furnace is heated at full power of 30 kW with a controllable heating rate until the melt temperature range of 1070 degrees Celsius is reached, then switched to constant power of 28 kW for stable holding). During the crystal growth start-up stage, each independent water-cooling circuit is opened, the motor is started, and the crucible rotates at a predetermined constant speed (e.g., a single-channel flow rate of 12 liters per minute and a constant crucible rotation of 15 revolutions per minute). During the annealing and cooling stage, after crystal growth is completed, the entire crystal is annealed and cooled at a predetermined rate to avoid internal stress and dislocation defects. After the temperature drops below the predetermined temperature, the pressure is released, the lid is opened, and the material is discharged (e.g., the entire crystal is annealed and cooled at a rate of 3 degrees Celsius per hour, and the pressure is released and the lid is opened when the temperature drops below 150 degrees Celsius). Through the synergistic design of the multi-station layout, independent temperature and cooling control, crucible rotation for uniform heating, and graded pressure-bearing sealing, the multi-station crystal growth device of the present invention fundamentally solves the technical problems of low single-furnace single-station capacity, mutual interference of multi-station thermal fields, low crystal growth efficiency due to static placement of crucibles, and poor reliability of high-pressure dynamic seals in the prior art, and significantly improves production efficiency, crystal quality, equipment uptime and operational stability.

[0058] In some embodiments, the inner wall of each crystal furnace 13 is provided with three independent spiral resistance heating wires arranged axially, divided into an upper heating section, a middle heating section, and a lower heating section from top to bottom. Each of the three heating wires is connected to an independent temperature control circuit, allowing for individual adjustment of output power and actively constructing a three-section axial process temperature zone: the upper section corresponds to the dissolution zone, with a rated operating temperature of 1070℃, exceeding the melting point of indium phosphide to create moderate superheat, ensuring complete melting of the polycrystalline raw materials in the crucible and maintaining a stable melt surface; the middle section corresponds to the transition zone, with an operating temperature of 1020–1050℃, forming a gentle axial temperature gradient to provide a stable mass transfer driving force for crystal growth; the lower section corresponds to the crystallization and protection zone, with an operating temperature of 950–1000℃, matching the solid-liquid interface crystallization temperature requirements while blocking high-temperature downward radiation, protecting the bottom transmission and sealing components. The three heating wires and the flow-blocking circular plate work together for control, combined with an independent water-cooling jacket structure, to achieve independent control of the temperature zone of a single furnace, with no axial thermal crosstalk.

[0059] During the melting and heating stage of the crystal raw material, the crucible support 16 drives the crucible to rotate unidirectionally at a constant speed of 1-5 rpm, preferably 2-3 rpm, to homogenize the circumferential temperature distribution of the melt, eliminate local temperature differences caused by circumferential asymmetry of the heating elements, accelerate the overall uniform melting of the polycrystalline raw material, and improve the compositional uniformity of the initial melt. After the raw material is completely melted, the support smoothly decelerates at a rate of ≤3 rpm / s until it stops completely, and holds the temperature stable for 10-30 minutes. After the melt flow completely subsides and the axial temperature field returns to a smooth state, the gradient cooling program is started to enter the crystal growth stage. Throughout the crystal growth process, the crucible remains stationary. Relying on the stable axial temperature gradient constructed by the independent heating wire and the flow-blocking circular plate, the melt is directionally solidified from bottom to top, ensuring a flat and regular solid-liquid interface and maintaining the crystal growth quality of low dislocation and low stress.

[0060] Figure 2 This is a partially enlarged schematic diagram of the flow-blocking circular plate in an embodiment of the present invention.

[0061] like Figure 2 As shown, and in combination Figure 1 In some embodiments, the multi-station crystal growth apparatus further includes at least two flow-blocking circular plates 27, which are spaced apart and arranged in the inner cavity of the autoclave body 1. Each flow-blocking circular plate 27 has a furnace body clearance through hole corresponding to each crystal furnace 13, and each crystal furnace 13 passes through the furnace body clearance through hole.

[0062] Preferably, the outer edge of the flow-blocking circular plate 27 is axially supported and positioned by support bosses evenly distributed around the inner wall of the autoclave body 1, and is fixed by high-temperature resistant positioning pins to prevent circumferential movement of the flow-blocking circular plate 27 under the impact of high-pressure gas. At least two flow-blocking circular plates are spaced apart in the inner cavity of the autoclave body 1, each with a clearance through hole corresponding to each crystal furnace, through which the crystal furnace 13 passes; the flow-blocking circular plates can narrow the airflow channel, suppress the large-scale axial convection of high-pressure protective gas, weaken the heat transfer of gas across temperature zones, and help stabilize the heat dissipation environment outside each crystal furnace.

[0063] Preferably, the flow-blocking circular plate 27 is a circular flat plate structure. Each flow-blocking circular plate 27 has the same number of furnace body clearance through holes as the crystal furnace 13. For example, when there are three crystal furnaces 13, the three furnace body clearance through holes are evenly arranged at 120° along the circumference of the flow-blocking circular plate 27. The inner diameter of the furnace body clearance through holes is larger than the outer diameter of the water-cooling jacket of the crystal furnace 13, with a pre-reserved assembly gap (e.g., 5 mm) on one side. This achieves both vertical limiting and coaxial positioning of the furnace body, and also allows for high-temperature thermal expansion. The furnace body clearance through holes form a small gap fit with the outer wall of the crystal furnace 13, allowing only a small amount of gas to flow slowly along the outer wall of the furnace body, preventing the formation of a through-type axial airflow channel, thereby blocking cross-temperature zone heat convection.

[0064] Melt crystal growth requires a high temperature gradient in the thermal field. Generally, an ideal temperature gradient is achieved through heating components, and then the temperature is slowly moved through process settings, allowing the melt to solidify slowly and stably, thus growing a high-quality single crystal.

[0065] The multi-station crystal growth apparatus disclosed in this application addresses the issue that, in a high-pressure crystal growth environment, the gas medium experiences strong convection due to the temperature gradient, disrupting the temperature gradient. The flow-blocking disc, by obstructing the airflow channel, weakens the gas convection, thereby stabilizing the temperature gradient.

[0066] Preferably, the flow-blocking circular plate 27 is made of high-temperature resistant GH4169 high-temperature alloy plate with a thickness of 10 mm. It can withstand long-term high temperature of 1070℃ and phosphorus vapor corrosion, and will not deform or warp at high temperature, ensuring that the flow-blocking sealing surface is flat.

[0067] Figure 3 This is a partially enlarged schematic diagram of the double sealing structure in the top cover of the autoclave.

[0068] like Figure 3 As shown, in some embodiments, the double sealing structure 14 includes two sets of axial sealing grooves 142 and two sets of end face sealing grooves 141.

[0069] Two sets of axial sealing grooves 142 are formed on the inner cylindrical wall of the autoclave cover 11, preferably rectangular closed annular grooves with vertical walls and flat bottoms. Sealing rings are embedded in each of the two sets of axial sealing grooves 142, using an embedded pre-installed method to completely fit the groove bottom and side walls. During assembly, the sealing rings undergo radial compression deformation, filling the gap between the cylinder and the side wall of the cover, achieving radial sealing.

[0070] Two sets of end-face sealing grooves 141 are formed on the upper end face of the top flange 18, preferably trapezoidal sealing grooves with a slightly wider opening and a slightly narrower bottom. Sealing gaskets are embedded in each of the two sets of end-face sealing grooves 141, using a flat, embedded installation method. Under the pre-tightening pressure of the bolts, the sealing gaskets undergo uniform axial deformation, filling the flange end-face contact gap and forming an axial high-pressure main seal.

[0071] Two sets of axial sealing grooves 142 correspond vertically to two sets of end face sealing grooves 141 and are coaxially arranged. The sealing grooves are arranged in parallel, have the same concentricity, and are not interconnected, forming a double axial superimposed sealing structure.

[0072] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A multi-station crystal growth apparatus, characterized in that, include: A high-pressure vessel body (1) is a sealed high-pressure container; its top end is provided with a top flange (18) for sealing with the high-pressure vessel cover (11); its bottom end is provided with a bottom flange (19) for connecting with the high-pressure vessel base; the high-pressure vessel body (1), the top flange (18) and the bottom flange (19) are integrally formed structures; A furnace bottom base (17) is fixedly installed inside the lower part of the autoclave body (1); At least two crystal furnaces (13) are evenly distributed on the furnace base (17) around the central axis of the autoclave body (1); each crystal furnace (13) is equipped with a heating component and a cooling component; each crystal furnace (13) is provided with a crucible support (16) inside, and the crucible support (16) is connected to a drive shaft; The pressure vessel base includes a pressure vessel base plate (26) and a base flange (21). The base flange (21) is located below the pressure vessel base plate (26). The pressure vessel base plate (26) and the base flange (21) are integrally formed. The pressure vessel base plate (26) is provided with a drive shaft channel. A magnetic fluid sealing structure (24) is provided at the drive shaft channel. The drive shaft passes through the drive shaft channel and is connected to a motor (23) to drive the crucible to rotate. The base flange (21) is used to bear the high-pressure static seal of the pressure vessel body, and the magnetic fluid sealing structure (24) is used to realize the dynamic seal when the drive shaft is rotating.

2. The multi-station crystal growth apparatus according to claim 1, characterized in that, Also includes: At least two flow-blocking circular plates (27) are spaced apart in the inner cavity of the autoclave body (1). Each flow-blocking circular plate (27) has a furnace body clearance through hole corresponding to each crystal furnace (13). Each crystal furnace (13) passes through the furnace body clearance through hole.

3. The multi-station crystal growth apparatus according to claim 1, characterized in that, Also includes: Multi-layer reflective heat insulation plates are spaced apart below the crucible support (16) and above the bottom of the crystal furnace (13). Each layer of reflective heat insulation plate is coaxially arranged with the corresponding crystal furnace (13), and a drive shaft through hole is opened in the center of each layer of reflective heat insulation plate.

4. The multi-station crystal growth apparatus according to claim 1, characterized in that, A heat insulation structure is provided between each crystal furnace (13), and the heat insulation structure includes at least one of a reflective cylinder, a heat radiation shielding layer, or a heat insulation baffle.

5. The multi-station crystal growth apparatus according to claim 1, characterized in that, The furnace base (17) is a disc structure. The plate of the furnace base (17) is provided with mounting stops corresponding to each crystal furnace (13). The lower end cylinder of each crystal furnace (13) is provided with a mounting flange. Each crystal furnace (13) is seated in the mounting stop. A high-temperature resistant sealing and heat insulation gasket is provided between the mounting flange and the furnace base (17), and they are detachably fixed together by fasteners.

6. The multi-station crystal growth apparatus according to claim 1, characterized in that, The cooling component is a water-cooled jacket (15), which is detachably fitted onto the outside of the crystal furnace (13); an annular gap is reserved between the water-cooled jacket (15) and the inner wall of the autoclave body (1).

7. The multi-station crystal growth apparatus according to claim 6, characterized in that, Each crystal furnace (13) is equipped with a cooling pipe for supplying water to the water-cooled jacket (15). The cooling pipe runs vertically through the furnace bottom base (17) and the high-pressure autoclave bottom plate (26). A high-temperature resistant heat-insulating sleeve is fitted between the cooling pipe and the furnace bottom base (17). A flange-type through-wall sealing joint is provided at the position where the cooling pipe passes through the high-pressure autoclave bottom plate (26). The annular gap between the high-temperature resistant heat-insulating sleeve and the cooling pipe is filled with high-temperature resistant sealing filler.

8. The multi-station crystal growth apparatus according to claim 1, characterized in that, The heating component is a heating wire, which is spirally arranged around the inner wall of each crystal furnace (13) and has a heat insulation layer between it and the inner wall of each crystal furnace (13).

9. The multi-station crystal growth apparatus according to claim 1, characterized in that, An annular support seat is provided on the lower inner wall of the autoclave body (1), and an annular support flange is provided on the outer edge of the furnace bottom base (17). The furnace bottom base (17) is integrally seated on the annular support seat through the annular support flange and is detachably fixed by fasteners. A high-temperature resistant heat insulation gasket is provided between the furnace bottom base (17) and the annular support seat.

10. The multi-station crystal growth apparatus according to any one of claims 1 to 9, characterized in that, The drive shaft channel is provided on the bottom plate (26) of the high pressure vessel corresponding to the center of each crystal furnace (13). The magnetic fluid sealing structure (24) is coaxially fixed to the lower side of the base flange (21). The drive shaft passes through the inner hole of the magnetic fluid sealing structure (24) and the drive shaft channel from bottom to top and is connected to the crucible bracket (16).

11. The multi-station crystal growth apparatus according to any one of claims 1 to 9, characterized in that, It also includes a pressure vessel cover (11), which is provided with a double sealing structure (14). The double sealing structure (14) includes an end face sealing groove (141) and an axial sealing groove (142). The axial sealing groove (142) is opened on the inner cylindrical wall of the pressure vessel cover (11) and a sealing ring is provided therein. The end face sealing groove (141) is opened on the upper end face of the top flange (18) and a sealing gasket is provided therein.

12. The multi-station crystal growth apparatus according to any one of claims 1 to 9, characterized in that, The rotation speed of the crucible support (16) can be adjusted according to the state of the crystal raw material and / or the temperature data collected in real time; the crucible support (16) can rotate forward, reverse, or switch between forward and reverse rotation.

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