A sapphire crystal growth furnace and a crystal growth method

Abstract

The application relates to the technical field of sapphire crystal growth, in particular to a sapphire crystal growth furnace and a crystal growth method, the sapphire crystal growth furnace comprising: a furnace body, the inside of the furnace body being provided with a furnace chamber, and a seed crystal channel being formed in the top of the furnace body and allowing a seed crystal rod to pass through; a heat preservation structure, the heat preservation structure being located in the furnace chamber, the heat preservation structure being in the form of a barrel, the heat preservation structure comprising a heat preservation side wall and a heat preservation top wall, the heat preservation side wall and the heat preservation top wall being combined to form a heat preservation cavity for crystal growth heat preservation, a through hole being formed in the heat preservation top wall and penetrating through the heat preservation top wall, and the through hole and the seed crystal channel being located in the same vertical space; and a blocking mechanism, the blocking mechanism being located in the furnace chamber and being used for blocking the through hole; the blocking mechanism can block the through hole in the material boiling stage, and the technical effect of improving the sapphire crystal growth quality is achieved.

Description

Technical Field

[0001] This application relates to the field of sapphire crystal growth technology, and in particular to a sapphire crystal growth furnace and a crystal growth method. Background Technology

[0002] The Kyropoulos method is currently the mainstream technology for preparing large-size, high-quality sapphire single crystals. Its core process is as follows: high-purity alumina raw material is added into the crucible in one go, and the raw material is completely melted into alumina melt through high-temperature boiling. Then, the seed crystal is lowered from the central through hole of the insulated barrel to the surface of the melt through the seed crystal rod. After the crystal is introduced, the single crystal is grown by precise temperature control.

[0003] In the existing technology, during the boiling process, trace amounts of alkali metals, silicon, iron and other impurities in the alumina raw materials, as well as trace amounts of high-temperature volatiles from the crucible and hot zone components, can cause contaminants to float upwards and contaminate the suspended seed crystals, thus affecting the quality of crystal growth.

[0004] Therefore, the technical problem with the existing technology is that the sapphire crystal growth quality is relatively low. Summary of the Invention

[0005] This application provides a sapphire crystal growth furnace and growth method. By using a barrier mechanism, the through holes can be blocked during the boiling stage, thereby improving the quality of sapphire crystal growth.

[0006] On the one hand, the sapphire crystal growth furnace and growth method provided in this application adopt the following technical solution: A sapphire crystal growth furnace, comprising: The furnace body has a furnace chamber inside, and a seed crystal channel is provided on the top of the furnace body to allow the seed crystal rod to pass through; A heat-insulating structure is located inside the furnace chamber. The heat-insulating structure is barrel-shaped and includes a heat-insulating side wall and a heat-insulating top wall. The heat-insulating side wall and the heat-insulating top wall enclose a heat-insulating cavity for crystal growth. A through hole is opened on the heat-insulating top wall, and the through hole and the seed crystal channel are located in the same vertical space. A blocking mechanism is located inside the furnace chamber and is used to block the through hole.

[0007] Preferably, the blocking mechanism includes a blocking plug, the blocking plug having a degree of freedom of movement, and the blocking plug's movement can be configured into at least a first state and a second state: In the first state, the blocking plug is inserted into the through hole to block the through hole; In the second state, the blocking plug disengages from the through hole, thereby opening the through hole.

[0008] Preferably, the barrier plug includes: Part One; The second part is fixedly connected below the first part, and the second part is used to adsorb impurities that float to the surface.

[0009] Preferably, the first part is tungsten or molybdenum; the second part is an active tungsten or molybdenum porous body.

[0010] Preferably, a transition space is formed between the heat-insulating top wall of the heat-insulating structure and the inner top surface of the furnace body; The blocking mechanism further includes a transmission assembly located within the transition space. The transmission assembly includes: A drive wheel is rotatably connected to the inner top surface of the furnace body, and the drive wheel can rotate around an axis; A tungsten wire rope is wound around the drive wheel, with one end of the tungsten wire rope connected to the seed crystal rod and the second end of the tungsten wire rope connected to the blocking plug, so that when the seed crystal rod descends, the blocking plug is pulled away from the through hole by the tungsten wire rope, thereby opening the through hole.

[0011] Preferably, the system also includes multiple sets of nozzles, which are disposed on the inner sidewall of the furnace body. The height of the nozzles is higher than the plane of the insulation top wall, and the nozzles are disposed corresponding to the center of the through hole. The multiple sets of nozzles are centrally symmetrically arranged along the circumference of the through hole. The nozzles are used to spray argon gas, and the spray direction is horizontally upward towards the through hole.

[0012] Preferably, the height of the nozzle is higher than the plane of the insulation top surface by a set distance, which is 1 / 6 to 5 / 6 of the height of the barrier plug; At least one of the nozzles is arranged on the movement path of the blocking plug when it switches from the first state to the second state; when the blocking plug switches to the second state, it blocks the jet path of the nozzle, causing the upward pollutants to be guided to the side under the action of asymmetric airflow.

[0013] Preferably, the heat-insulating top wall is provided with a guide groove, which is used to guide and limit the movement of the blocking plug so that the blocking plug blocks the jet path of the nozzle when it moves.

[0014] On the other hand, the sapphire crystal growth method provided in this application adopts the following technical solution: A crystal growth method for a sapphire crystal growth furnace, comprising: Crystal growth raw materials are loaded into the crucible inside the furnace, and the through holes in the heat-insulating top wall are sealed with a barrier plug to carry out the cooking process. The seed crystal rod is lowered, and the tungsten wire rope drives the barrier plug to disengage from the through hole, thus opening the through hole; The seed crystal rod continues to descend, extending into the crucible to complete the crystal development.

[0015] A crystal growth method for a sapphire crystal growth furnace, comprising: Crystal growth raw materials are loaded into the crucible inside the furnace, and the through holes in the heat-insulating top wall are sealed with a barrier plug to carry out the cooking process. The seed crystal rod is controlled to descend, causing the blocking plug to disengage from the through hole and block the nozzle, so that multiple nozzles form an asymmetric airflow and guide the flow to the side. The seed crystal rod continues to descend, extending into the crucible to complete the crystal development.

[0016] In summary, this application includes at least one of the following beneficial technical effects: The barrier mechanism can block the through holes during the cooking stage, preventing contaminants from floating upwards and avoiding contact with the seed crystal. This effectively solves the technical problem of contaminants polluting the seed crystal and causing low crystal growth quality in existing technologies. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the sapphire crystal growth furnace described in this application; Figure 2 This is a schematic diagram of the barrier plug state of the sapphire crystal growth furnace described in this application; Figure 3 This is a schematic diagram of the barrier plug of the sapphire crystal growth furnace described in this application; Figure 4 This is a schematic diagram of the barrier mechanism of the sapphire crystal growth furnace described in this application; Figure 5 This is a schematic diagram of the first type of transmission assembly of the sapphire crystal growth furnace described in this application; Figure 6 This is a second schematic diagram of the transmission assembly of the sapphire crystal growth furnace described in this application; Figure 7 This is a third schematic diagram of the transmission assembly of the sapphire crystal growth furnace described in this application; Figure 8 This is a schematic diagram of the nozzle of the sapphire crystal growth furnace described in this application; Figure 9 This is a top view of the nozzle of the sapphire crystal growth furnace described in this application; Figure 10 This is a schematic diagram of the nozzle flow guide of the sapphire crystal growth furnace described in this application; Figure 11 This is a top view of the nozzle guide of the sapphire crystal growth furnace described in this application; Figure 12 This is a schematic diagram of the first process of the crystal growth method of the sapphire crystal growth furnace described in this application; Figure 13 This is a schematic diagram of the second process of the crystal growth method of the sapphire crystal growth furnace described in this application.

[0018] Explanation of reference numerals in the attached drawings: 100, furnace body; 110, furnace chamber; 111, transition space; 120, seed crystal channel; 200, insulation structure; 210, insulation side wall; 220, insulation top wall; 221, through hole; 230, insulation cavity; 300, barrier mechanism; 310, barrier plug; 311, first part; 312, second part; 320, transmission assembly; 321, transmission wheel; 322, tungsten wire rope; 400, nozzle; 410, airflow barrier; 500, seed crystal rod; 510, seed crystal; 600, crucible. Detailed Implementation

[0019] The serial numbers assigned to components in this document, such as "first" and "second," are used solely to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used solely for the convenience of describing this application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0020] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0021] To better understand the above technical solutions, a detailed description of the technical solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit the scope of this application.

[0022] This application proposes a sapphire crystal growth furnace, such as Figure 1As shown, the system includes a furnace body 100, a thermal insulation structure 200, and a barrier mechanism 300. These three components work together to form the basic equipment framework for sapphire crystal growth, providing a stable growth environment for subsequent crystal growth processes and simultaneously addressing the problem of contaminants rising and contaminating the seed crystal 510. It should be noted that the thermal insulation structure 200 houses a crucible 600 and a heater. The crucible 600 is used to hold the sapphire raw material, and the heater is used to heat the raw material within the crucible 600. The seed crystal rod 500 passes through the furnace body 100 and the thermal insulation structure 200 to enter the crucible 600 for crystal point formation. The molten sapphire raw material begins to grow on the seed crystal 510 of the seed crystal rod 500.

[0023] The furnace body 100 serves as the supporting foundation for the entire growth furnace, and its interior contains a furnace chamber 110. A seed crystal channel 120, allowing the seed crystal rod 500 to pass through, is located at the top of the furnace body 100. The seed crystal channel 120 corresponds to the through-hole 221 of the insulation structure 200, providing a channel for the lifting and lowering movement of the seed crystal rod 500. This ensures that the seed crystal rod 500 can smoothly drive the seed crystal 510 into the crucible 600 to complete processes such as crystal introduction and growth. The size of the seed crystal channel 120 is slightly larger than the diameter of the seed crystal rod 500, ensuring both smooth lifting and lowering of the seed crystal rod 500 and maintaining the stability of the environment within the furnace chamber 110.

[0024] like Figure 1 As shown, the insulation structure 200 is located inside the furnace chamber 110 and is arranged in a barrel shape. The insulation structure 200 is used to provide a stable insulation environment for crystal growth, reduce heat loss in the furnace chamber 110, ensure that the high temperature required for crystal growth can be maintained in the furnace chamber 110, and at the same time avoid uneven temperature distribution in the furnace chamber 110, which would affect the uniformity of crystal growth. The insulation structure 200 includes an insulation side wall 210 and an insulation top wall 220. The insulation side wall 210 is cylindrical and surrounds the outside of the crucible 600 in the furnace chamber 110. The insulation top wall 220 covers the top of the insulation side wall 210. The two enclose each other to form an insulation cavity 230 for crystal growth insulation. The internal space of the insulation cavity 230 is adapted to the size of the crucible 600, which can completely enclose the crucible 600, realize all-round insulation of the crucible 600, and ensure that the alumina raw material in the crucible 600 can be uniformly heated and fully melted to form a stable alumina melt.

[0025] Among them, such as Figure 1As shown, a through hole 221 is provided on the insulating top wall 220, penetrating through the top wall 220. The position of the through hole 221 is in the same vertical space as the seed crystal channel 120 at the top of the furnace body 100, ensuring that when the seed crystal rod 500 drives the seed crystal 510 to descend, it can smoothly pass through the seed crystal channel 120 and the through hole 221, and enter the crucible 600 inside the insulating cavity 230 to contact the alumina melt and complete the crystal introduction. The diameter of the through hole 221 is slightly larger than the diameter of the seed crystal rod 500, which ensures that the seed crystal rod 500 can pass smoothly and reduces heat loss in the insulating cavity 230.

[0026] It should be noted that, generally, during the sapphire crystal growth process, the seed crystal rod 500, carrying the seed crystal 510, is pre-inserted into the seed crystal channel 120 at the top of the furnace body 100. This arrangement is based on two main considerations: Firstly, it allows the seed crystal rod 500 to quickly descend for crystal spotting after the sapphire crystal growth process is completed, avoiding delays in the process due to the subsequent installation of the seed crystal rod 500 and seed crystal 510, ensuring a stable melt state, and improving the success rate of crystal seeding. Secondly, the temperature inside the furnace chamber 110 is extremely high during the sapphire crystal growth process. If the seed crystal rod 500 and seed crystal 510 are installed after the sapphire crystal growth process is completed, the operators will not only face the safety risk of burns from the high temperature environment, but also face the risk of burns from the high temperature. This will also affect the installation accuracy of the seed crystal rod 500 and the seed crystal 510, and may even damage the seed crystal 510. For this reason, during the boiling stage, the seed crystal rod 500 and the seed crystal 510 will be located within the seed crystal channel 120. During the boiling process, trace amounts of alkali metals, silicon, iron and other impurities in the alumina raw material, as well as trace amounts of volatiles generated by the crucible 600 and the hot zone components at high temperatures, will continue to drift upwards under the action of thermal convection. The upward-drifting contaminants will directly contact the surface of the seed crystal rod 500 and the seed crystal 510 it carries, thereby contaminating the seed crystal rod 500 and the seed crystal 510. The contamination will be transferred to the alumina melt during the subsequent crystal pulling process, ultimately affecting the growth quality of the sapphire crystal.

[0027] Therefore, as Figure 1As shown, this application includes a blocking mechanism 300 located within the furnace chamber 110. The blocking mechanism 300 is used to seal the through-hole 221 on the insulation top wall 220. During the boiling stage of crystal growth, sealing the through-hole 221 prevents contaminants in the furnace chamber 110 from rising upwards, thus avoiding contaminants suspending below the seed crystal channel 120 on the seed crystal 510. The installation position of the blocking mechanism 300 corresponds to the through-hole 221, enabling precise coverage and blockage of the through-hole 221, achieving effective sealing of the through-hole 221. During the boiling stage... During the material feeding stage, the blocking mechanism 300 is in a blocked state, completely sealing the through hole 221. At this time, the alumina raw material in the crucible 600 melts at high temperature, and the volatile impurities and pollutants generated are blocked by the blocking mechanism 300 inside the heat preservation cavity 230 and cannot float upward through the through hole 221, thus avoiding contamination of the seed crystal 510. During the crystal pulling stage, the blocking mechanism 300 disengages from the through hole 221, opening the through hole 221 to ensure that the seed crystal rod 500 can drive the seed crystal 510 to descend smoothly and enter the crucible 600 to complete the crystal pulling.

[0028] Furthermore, such as Figure 1 , 2 As shown, the barrier mechanism 300 includes a barrier plug 310, which has two active states. By switching between the two states, the through hole 221 can be blocked and opened, further optimizing the working effect of the barrier mechanism 300 and ensuring that the barrier mechanism 300 can accurately adapt to different stages of crystal growth.

[0029] like Figure 1 , 2 As shown, the barrier plug 310 is adapted to the through hole 221 on the insulation top wall 220, and can be precisely locked into the through hole 221 to effectively seal the through hole 221. The barrier plug 310 has a degree of freedom of movement, which allows the barrier plug 310 to move within the furnace chamber 110, thereby realizing the switching between two states, namely the first state and the second state. The two states correspond to the boiling stage and the crystal growth stage, respectively, and are matched with the process rhythm of crystal growth.

[0030] In the first state, the barrier plug 310 is engaged within the through hole 221. At this time, the outer surface of the barrier plug 310 is tightly fitted to the inner wall of the through hole 221, completely sealing the through hole 221 and achieving a good sealing effect. This first state corresponds to the boiling stage of crystal growth. At this time, the alumina raw material in the crucible 600 is melting at high temperature, generating a large amount of volatile impurities and contaminants. These contaminants will float upwards under the action of thermal convection. The sealing effect of the barrier plug 310 can block these contaminants inside the insulation cavity 230, preventing them from diffusing upwards through the through hole 221. This avoids contaminants contacting the seed crystal 510 suspended below the seed crystal channel 120, ensuring the cleanliness of the seed crystal 510. In the first state, the barrier plug 310 can be engaged by an interference fit or by a positioning structure, ensuring that the barrier plug 310 will not loosen under high temperature and vibration conditions, maintaining effective sealing of the through hole 221 and preventing contaminant leakage due to loosening of the barrier plug 310.

[0031] In the second state, the blocking plug 310 disengages from the through hole 221, which is now fully open, providing a smooth path for the descent of the seed crystal rod 500 and the seed crystal 510. This second state corresponds to the crystal growth stage. After the boiling process is completed and the alumina material in the crucible 600 is completely melted into a uniform melt, the blocking plug 310 needs to be disengaged from the through hole 221 so that the seed crystal rod 500 can smoothly lower the seed crystal 510, pass through the through hole 221, and enter the insulation cavity 230 to contact the melt and complete the crystal growth. After the blocking plug 310 disengages from the through hole 221, it will remain at a specific position in the furnace chamber 110, without affecting the movement path of the seed crystal rod 500 and the seed crystal 510, ensuring the smooth progress of the crystal growth process.

[0032] The barrier plug 310 has two states. In the first state, it blocks the flow of contaminants during the cooking stage. In the second state, it opens the flow of the crystal growth process. The switching between the two states is precisely matched with the process rhythm of crystal growth, which not only ensures the control of contaminants, but also does not affect the normal production process. At the same time, the barrier plug 310's design with a degree of freedom of movement allows it to switch states flexibly without the need for a complex drive mechanism. Its simple structure and convenient operation further improve the practicality and reliability of the equipment.

[0033] Furthermore, such as Figure 3 As shown, the barrier plug 310 includes a first part 311 and a second part 312. The second part 312 is fixedly connected to the lower part of the first part 311 and is used to adsorb impurities floating in the air. Through the design of the layered structure, the pollutant control effect of the barrier mechanism 300 is further improved, achieving dual protection of blocking and adsorption of pollutants, and further reducing the contamination of the seed crystal 510 by pollutants.

[0034] The dimensions of the first part 311 are adapted to the dimensions of the through hole 221, allowing it to be fitted into the through hole 221 and forming a good sealing effect. The top of the first part 311 is connected to the tungsten wire rope 322 of the transmission assembly 320 to realize the state switching of the blocking plug 310. Under the traction of the seed crystal rod 500, the entire blocking plug 310 is moved to realize the switching from the first state to the second state.

[0035] The second part 312 is fixedly connected below the first part 311, located on the side of the first part 311 facing the insulation cavity 230. When the barrier plug 310 is in the first state, the second part 312 is at least partially exposed inside the insulation cavity 230. The core function of the second part 312 is to adsorb impurities that float upwards. During the cooking stage, volatile pollutants generated in the crucible 600 will float upwards. The second part 312 can adsorb the pollutants, preventing them from continuing to float upwards, thus further improving the pollutant control effect. The setting of the second part 312 makes up for the shortcomings of relying solely on the first part 311 for sealing. Even if there is a small gap between the first part 311 and the through hole 221, the adsorption effect of the second part 312 can intercept the leaked small pollutants, preventing them from contaminating the seed crystal 510. The dual protection structure of sealing and adsorption can significantly improve the pollutant control capability of the barrier mechanism 300, further solving the problem of pollutants contaminating the seed crystal 510 in the prior art, and improving the growth quality of sapphire crystals.

[0036] In one embodiment, the first part 311 is tungsten or molybdenum, and the second part 312 is an active tungsten or molybdenum porous body. This material selection can ensure that the barrier plug 310 is compatible with the high-temperature environment inside the furnace chamber 110, while ensuring the adsorption effect of the second part 312, avoiding the generation of contaminants by the barrier plug 310 itself, and further improving the crystal growth quality.

[0037] Within the sapphire crystal growth furnace chamber 110, temperatures can reach over 2000℃ during the boiling stage, creating a high-temperature environment. Therefore, the material of the barrier plug 310 must possess excellent high-temperature resistance, maintaining structural stability under high-temperature conditions without melting, deformation, or volatilization. This prevents contaminant generation due to the volatilization or deformation of the barrier plug 310 itself, which could then contaminate the seed crystal 510 and the melt. Tungsten and molybdenum are two metallic materials with excellent high-temperature resistance, both having melting points above 2000℃. They are perfectly suited to the high-temperature environment within the furnace chamber 110, maintaining structural stability at the high temperatures of the boiling stage without melting or deformation. Furthermore, their chemical properties are stable, preventing chemical reactions with the alumina melt and argon gas within the furnace chamber 110, thus avoiding the generation of additional contaminants and ensuring the cleanliness of the crystal growth environment. Therefore, using tungsten or molybdenum as the material for the first part 311 ensures its structural and chemical stability under high-temperature conditions, effectively sealing the through-hole 221 while preventing the generation of contaminants.

[0038] The material of the second part 312 is an activated tungsten or molybdenum porous body. Activated tungsten and activated molybdenum have good adsorption properties and can effectively adsorb volatile impurities, fine dust and other pollutants generated during the cooking stage. The porous structure has a large specific surface area, which can significantly improve the adsorption capacity and can adsorb volatile metal oxides (WO3, MoO3) and be reduced back to metal deposits without generating foreign impurities. This ensures that the second part 312 can adsorb more pollutants and further improve the adsorption effect. At the same time, the activated tungsten and activated molybdenum porous bodies also have excellent high temperature resistance and can maintain stable adsorption performance in the high temperature environment of the furnace chamber 110. The adsorption performance will not decrease or fail due to high temperature. In addition, the activated tungsten and activated molybdenum porous bodies are compatible with the tungsten or molybdenum material of the first part 311. They can be fixedly connected by welding, integral molding and other methods. The connection is firm and not easy to fall off, ensuring that the second part 312 can move synchronously with the first part 311 and always play an adsorption role. In other embodiments, the second part 312 can also be a high-purity alumina trap or a high-purity porous alumina base, which has a strong adsorption and solid solution capacity for water vapor, alkali metal ions, SiO, etc., and is itself a crystalline raw material that will not contaminate the system.

[0039] Furthermore, such as Figure 4-7 As shown, a transition space 111 is formed between the insulation top wall 220 of the insulation structure 200 and the inner top surface of the furnace body 100. The transmission component 320 is located in the transition space 111 and includes a transmission wheel 321 and a tungsten wire rope 322. The transmission component 320 realizes the linkage between the seed crystal rod 500 and the blocking plug 310, so that when the seed crystal rod 500 descends, it can pull the blocking plug 310 away from the through hole 221 through the tungsten wire rope 322, thereby opening the through hole 221. No additional drive mechanism is required, which simplifies the equipment structure and improves the automation level and reliability of the equipment.

[0040] like Figure 4 As shown, a transition space 111 is formed between the insulation top wall 220 of the insulation structure 200 and the inner top surface of the furnace body 100. The transition space 111 is located in the upper part of the furnace chamber 110, above the insulation structure 200 and below the seed crystal channel 120. The transition space 111 provides installation space for the transmission component 320 and provides movement space for the blocking plug 310, avoiding interference with other components when the blocking plug 310 moves. The height of the transition space 111 is adapted to the movement stroke of the blocking plug 310, ensuring that the blocking plug 310 can completely detach from the through hole 221 and stay stably in the transition space 111 without affecting the movement path of the seed crystal rod 500 and the seed crystal 510.

[0041] like Figure 4-6As shown, the transmission assembly 320 is located within the transition space 111. The transmission assembly 320 is used to link the seed crystal rod 500 with the barrier plug 310. The transmission assembly 320 includes a transmission wheel 321 and a tungsten wire rope 322. The transmission wheel 321 is rotatably connected to the inner top surface of the furnace body 100 and can rotate around its own axis. The material of the transmission wheel 321 is the same as that of the first part 311 of the barrier plug 310, which is tungsten or molybdenum, ensuring that it can adapt to the high-temperature environment inside the furnace chamber 110, maintain structural stability at high temperatures, rotate flexibly, and will not jam or be damaged. The number of transmission wheels 321 can be set to one or more according to actual needs. When multiple wheels are used, it ensures that the traction direction of the tungsten wire rope 322 is stable enough to pull up the barrier plug 310 to achieve the switching between the first and second states of the barrier plug 310.

[0042] like Figure 4-6 As shown, a tungsten wire rope 322 is wound around a transmission wheel 321. The first end of the tungsten wire rope 322 is fixedly connected to the seed crystal rod 500, and the second end is fixedly connected to the blocking plug 310, forming a complete traction transmission structure. The tungsten wire rope 322 is made of high-purity tungsten material, possessing excellent high-temperature resistance and tensile strength. It can maintain structural stability in the high-temperature environment of the furnace chamber 110 without breaking or melting. Simultaneously, its smooth surface results in low friction with the transmission wheel 321, ensuring smooth transmission. The length of the tungsten wire rope 322 is precisely designed to ensure that when the seed crystal rod 500 is at its highest position, the blocking plug 310 is fully engaged in the through hole 221, in the first state. When the seed crystal rod 500 descends, the tungsten wire rope 322, through the transmission wheel 321, pulls the blocking plug 310 upwards, disengaging it from the through hole 221, switching to the second state, and opening the through hole 221. Figure 7 As shown, it should be noted that the length of the tungsten wire rope 322 is precisely designed, and the installation position of the transmission wheel 321 is rationally arranged to achieve the position switching of the blocking plug 310 between the first and second states. The connection position between the tungsten wire rope 322 and the seed crystal rod 500 can be flexibly adjusted according to the actual equipment layout, the stroke of the seed crystal rod 500, and other practical considerations to adapt to different equipment specifications. Since the through-hole 221 of the insulation structure 200 is slightly larger than the diameter of the seed crystal rod 500, the tungsten wire rope 322 can enter the insulation structure 200 along with the seed crystal rod 500 during its descent. Furthermore, the tungsten wire rope 322 itself has a high melting point, enabling it to withstand the high-temperature environment within the insulation structure 200 without introducing any impurities into the furnace chamber 110, thus ensuring the cleanliness of the crystal growth environment.

[0043] It should be noted that in the sapphire bubble growth process, the seed crystal rod 500 typically does not require rotation, thus preventing the tungsten wire rope 322 from winding around the axis. In some embodiments, for different crystal growth requirements, the first end of the tungsten wire rope 322 can be fitted onto the seed crystal rod 500 via a collar, limiting the collar's vertical position and preventing it from moving up and down along the axial direction of the seed crystal rod 500. Only relative rotation between the seed crystal rod 500 and the collar is achieved. With this structural design, even if the seed crystal rod 500 needs to rotate in some process scenarios, the relative rotation between the collar and the seed crystal rod 500 keeps the tungsten wire rope 322 stationary with the collar, effectively avoiding the problem of the tungsten wire rope 322 winding around the axis and ensuring the stability of equipment operation and the smoothness of the process.

[0044] like Figure 4-7 As shown, during the boiling stage, the seed crystal rod 500 is at its highest position, and the blocking plug 310 is locked inside the through hole 221, in the first state, sealing the through hole 221. When the boiling process is completed and crystal pulling is required, the seed crystal rod 500 is controlled to descend. During the descent of the seed crystal rod 500, the first end of the tungsten wire rope 322 moves downward. The taut tungsten wire rope 322 transmits the tension to the blocking plug 310 through the guiding action of the transmission wheel 321, pulling the blocking plug 310 upward and gradually disengaging it from the through hole 221. When the seed crystal rod 500 descends to a certain position, the blocking plug 310 completely disengages from the through hole 221, switching to the second state, and the through hole 221 is in the open state. At this time, the seed crystal rod 500 can continue to descend, driving the seed crystal 510 through the through hole 221 into the heat preservation cavity 230, completing the crystal pulling process.

[0045] The transmission component 320 enables the linkage between the seed crystal rod 500 and the barrier plug 310. No additional drive mechanism is needed for the barrier plug 310; the state switching of the barrier plug 310 can be achieved solely through the lifting and lowering movement of the seed crystal rod 500. This simplifies the equipment structure and reduces manufacturing costs and maintenance difficulty. Simultaneously, the linkage design ensures precise synchronization between the state switching of the barrier plug 310 and the lifting and lowering movement of the seed crystal rod 500, eliminating the need for manual intervention and improving the automation level and operational reliability of the equipment, ensuring the smooth progress of the crystal growth process. Furthermore, the transmission component 320 is located within the transition space 111, thus not affecting the insulation effect of the insulation cavity 230 or interfering with other components within the furnace chamber 110, further enhancing the practicality of the equipment.

[0046] Furthermore, such as Figure 8 , 9As shown, multiple sets of nozzles 400 are installed on the inner side wall of the furnace body 100. Argon gas is sprayed through the nozzles 400 to form an airflow barrier 410, which further intercepts pollutants. Together with the barrier mechanism 300, it can control pollutants and improve the quality of crystal growth.

[0047] Specifically, such as Figure 8 , 9 As shown, the nozzle 400 is installed on the inner wall of the furnace body 100. The installation height of the nozzle 400 is higher than the plane of the insulation top wall 220, which ensures that the argon gas injected by the nozzle 400 can form an airflow barrier 410 above the through hole 221, intercepting contaminants that float upwards after the through hole 221 is opened, and preventing contaminants from contacting the seed crystal 510. The installation position of the nozzle 400 corresponds to the through hole 221, ensuring that the argon gas injected by the nozzle 400 can accurately cover the area above the through hole 221, forming an effective airflow protection. More specifically, there are multiple sets of nozzles 400, which are centrally symmetrically arranged along the circumference of the through hole 221. The central symmetrical arrangement ensures that the argon gas injected by the nozzle 400 forms a uniform airflow field above the through hole 221, avoiding protection gaps caused by uneven airflow distribution, and ensuring all-round interception of contaminants.

[0048] Nozzle 400 is used to inject argon gas. Argon is an inert gas with stable chemical properties and will not react chemically with the molten alumina, seed crystal 510, or hot zone components in the furnace chamber 110, thus preventing the generation of additional contaminants. Furthermore, argon gas has good thermal conductivity and fluidity, enabling it to form a stable airflow barrier 410 above the through-hole 221. The nozzle 400 is positioned horizontally above the through-hole 221. This horizontal injection ensures that the argon gas forms a horizontal airflow barrier 410 above the through-hole 221, preventing it from impacting the molten material inside the insulation cavity 230 and thus avoiding affecting the temperature distribution and stability of the molten material. Simultaneously, it will not directly impact or contaminate the seed crystal 510.

[0049] like Figure 8 , 9 As shown, the centrally symmetrical arrangement of multiple nozzles 400 ensures the uniformity of the airflow field, avoids dead zones in the airflow, and ensures comprehensive coverage of the area above the through hole 221. At the same time, the nozzles 400 are set on the inner wall of the furnace body 100, so they will not affect the movement of the seed crystal rod 500, the blocking plug 310, and the transmission component 320. The airflow barrier 410 formed by the argon gas sprayed by the nozzles 400, combined with the blocking and adsorption effects of the blocking mechanism 300, forms a triple pollution control system of blocking, adsorption, and airflow interception. This further solves the problem of pollutants contaminating the seed crystal 510 in the prior art and significantly improves the growth quality of sapphire crystals.

[0050] Furthermore, such as Figure 10 ,11 As shown, the nozzle 400 has a jet outlet height that is higher than the plane of the insulation top wall 220 by a set distance. This set distance is 1 / 6 to 5 / 6 of the height of the barrier plug 310. At the same time, at least one nozzle 400 is arranged on the movement path of the barrier plug 310 when it switches from the first state to the second state. When the barrier plug 310 switches to the second state, it blocks the jet path of the nozzle 400, causing the upward pollutants to be guided to the side under the action of asymmetric airflow, further optimizing the airflow control effect, realizing the directional removal of pollutants, and completely solving the problem of secondary pollution of pollutants.

[0051] like Figure 10 , 11 As shown, the height of the nozzle 400 is higher than the plane of the insulation top wall 220 by a set distance. This set distance is 1 / 6 to 5 / 6 of the height of the blocking plug 310. This height limit can ensure that the nozzle 400's air outlet is matched with the movement trajectory of the blocking plug 310. This ensures that the argon gas ejected by the nozzle 400 forms an effective airflow barrier 410 above the through hole 221, and also ensures that when the blocking plug 310 switches to the second state, it can accurately block the airflow path of the corresponding nozzle 400. Furthermore, at least one nozzle 400 is arranged on the movement path of the blocking plug 310 from the first state to the second state. It can be understood that when the seed crystal rod 500 descends, the blocking plug 310, under the traction of the seed crystal rod 500, will move along the preset movement path when it switches from the first state (stuck in the through hole 221) to the second state (detached from the through hole 221). The nozzle 400 is located in the extension direction of the movement path of the blocking plug 310, so that the blocking plug 310 can block the jet path of the nozzle 400. After the blocking plug 310 switches to the second state, it will at least partially stop in front of the nozzle 400, blocking the jet path of the nozzle 400, so that the argon gas ejected by the nozzle 400 cannot reach the top of the through hole 221 normally. At this time, among the multiple sets of nozzles 400, the blocked nozzle 400 cannot eject gas, while the other nozzles 400 eject gas normally. The originally centrally symmetrical uniform airflow field is broken, forming an asymmetrical airflow.

[0052] like Figure 10 , 11As shown, the formation of asymmetric airflow generates directional airflow thrust, guiding contaminants floating upwards from the through-hole 221 to the side. During the cooking stage, the blocking plug 310 seals the through-hole 221, and multiple sets of nozzles 400 spray air symmetrically, forming a uniform airflow barrier 410 to intercept a small amount of escaping contaminants. As the seed crystal rod 500 descends, the blocking plug 310 disengages from the through-hole 221 and blocks one nozzle 400, forming an asymmetric airflow. At this time, the through-hole 221 opens, and the contaminants float upwards. Under the directional thrust of the asymmetric airflow, the contaminants are forced to flow to the side, away from the central axis of the through-hole 221, while the seed crystal rod 500 and the seed crystal 510 descend along the central axis of the through-hole 221. Therefore, the contaminants will not come into contact with the seed crystal 510, achieving directional removal of contaminants and completely solving the problem of secondary contamination of the seed crystal 510 by contaminants after the plug opens.

[0053] like Figure 10 , 11 As shown, as the seed crystal rod 500 continues to descend, passing through the open through-hole 221, it carries the seed crystal 510 smoothly into the insulation cavity 230, gradually approaching the alumina melt in the crucible 600. When the seed crystal 510 contacts the surface of the melt and completes the crystal pulling operation, after the seed crystal rod 500 descends to the preset crystal pulling position and completes the descent action, the blocking plug 310, which was originally pulled by the tungsten wire rope 322 to block the jet path of the nozzle 400, is suspended. That is, the blocking plug 310 no longer blocks the jet path of the nozzle 400. At this time, the jet airflow of the multiple sets of nozzles 400 is restored to a symmetrical and stable horizontal airflow field, thereby forming a continuous and stable airflow barrier 410 in the through-hole 221, improving the internal stability of the insulation structure 200.

[0054] Furthermore, a guide groove (not shown) is provided on the insulated top wall 220. The guide groove is used to guide and limit the movement of the blocking plug 310 so that the blocking plug 310 can accurately block the jet path of the nozzle 400 when it moves, avoid the blocking plug 310 from deviating when it moves, and ensure the accuracy and reliability of the airflow field switching.

[0055] A guide groove is disposed on the upper surface of the insulated top wall 220, arranged along the movement path of the barrier plug 310. Its length is adapted to the movement stroke of the barrier plug 310, and its width is adapted to or slightly larger than the size of the barrier plug 310, thus guiding and limiting the movement of the barrier plug 310. The material of the guide groove is the same as that of the insulated top wall 220, ensuring that it can adapt to the high-temperature environment inside the furnace chamber 110, maintain structural stability at high temperatures, and will not deform or be damaged.

[0056] Thus, when the seed crystal rod 500 descends and the blocking plug 310 is pulled from the first state to the second state by the tungsten wire rope 322, the bottom of the blocking plug 310 will be embedded in the guide groove and move along the extension direction of the guide groove. The guide groove can restrict the movement direction of the blocking plug 310, prevent the blocking plug 310 from shifting left or right during the movement, and ensure that the blocking plug 310 can move accurately along the preset movement path and finally stop at the preset position to block the jet path of the corresponding nozzle 400. Without the guide groove, the barrier plug 310 may deviate during movement due to uneven tension of the tungsten wire rope 322, airflow disturbance in the furnace chamber 110, etc., resulting in the inability to accurately block the jet path of the nozzle 400, failing to form an effective asymmetric airflow, thus affecting the directional flow of pollutants, and may even cause pollutants to come into contact with the seed crystal 510. Therefore, the accuracy and reliability of the movement of the barrier plug 310 are further improved to ensure that the barrier plug 310 can accurately block the jet path of the corresponding nozzle 400 at each state switch, realize the stable switching of the airflow field, and thus ensure the directional flow of pollutants.

[0057] This application proposes a crystal growth method for the aforementioned crystal growth furnace, such as... Figure 12 As shown, the process includes: S11: Filling the crucible 600 in the furnace with crystal growth raw materials, so that the blocking plug 310 blocks the through hole 221 of the heat preservation top wall 220, and carrying out the material cooking process; S12: Controlling the seed crystal rod 500 to descend, and driving the blocking plug 310 to disengage from the through hole 221 through the tungsten wire rope 322, so that the through hole 221 is opened; S13: The seed crystal rod 500 continues to descend and extends into the crucible 600 to complete the crystal pulling.

[0058] Specifically, crystal growth material, high-purity alumina powder, is loaded into the crucible 600 inside the furnace. After loading, the position of the seed crystal rod 500 is adjusted so that it is inserted into the seed crystal channel 120 and kept suspended, with the seed crystal rod 500 at its highest position. The blocking plug 310 is then inserted into the through hole 221 of the insulation top wall 220 to seal the through hole 221. Subsequently, the growth furnace is started to begin the boiling process. The core purpose of the boiling process is to completely melt the alumina raw material into a uniform alumina melt. During the boiling process, the growth furnace raises the temperature inside the furnace chamber 110 to above 2000℃ to ensure that the alumina raw material is fully melted. During the boiling process, the blocking plug 310 is in its first state, sealing the through hole 221 and preventing contaminants generated inside the crucible 600 from floating upwards, thus avoiding contamination of the seed crystal 510 suspended below the seed crystal channel 120.

[0059] Once the boiling process is complete, the alumina raw material in the crucible 600 is completely melted into a uniform melt, and the temperature and purity of the melt meet the requirements for crystal development, the seed crystal rod 500 is controlled to descend. During the descent of the seed crystal rod 500, the first end of the tungsten wire rope 322 moves downward. The taut tungsten wire rope 322 transmits the tension to the blocking plug 310 through the transmission wheel 321, pulling the blocking plug 310 upward and gradually disengaging it from the through hole 221 of the insulation top wall 220. When the seed crystal rod 500 descends to a certain position, the blocking plug 310 completely disengages from the through hole 221, switching to the second state, and the through hole 221 is in the open state.

[0060] The seed crystal rod 500 continues to descend, passing through the open through hole 221, and bringing the seed crystal 510 into the heat preservation cavity 230, gradually approaching the alumina melt in the crucible 600 for crystal introduction and growth.

[0061] Furthermore, this application also proposes another crystal growth method for a crystal growth furnace, such as... Figure 13 As shown, it includes: S21: Fill the crucible 600 in the furnace with crystal growth raw materials, and block the through hole 221 of the heat preservation top wall 220 with the barrier plug 310 to carry out the boiling process; S22: Control the seed crystal rod 500 to descend, drive the barrier plug 310 to disengage from the through hole 221 and block the nozzle 400, so that the multiple sets of nozzles 400 form an asymmetric airflow and guide it to the side; S23: The seed crystal rod 500 continues to descend and extends into the crucible 600 to complete the crystal pulling.

[0062] Specifically, crystal growth raw material, namely high-purity alumina powder, is loaded into the crucible 600 inside the furnace. After loading, the position of the seed crystal rod 500 is adjusted so that it is inserted into the seed crystal channel 120 and kept suspended, with the seed crystal rod 500 at its highest position. The blocking plug 310 is inserted into the through hole 221 of the insulation top wall 220 to seal the through hole 221. Then, the growth furnace is started to begin the cooking process. At the same time as the cooking process begins, the nozzle 400 is started to spray high-purity argon gas above the through hole 221. Multiple sets of nozzles 400 are arranged symmetrically in the center. The sprayed argon gas forms a uniform horizontal airflow barrier 410 above the through hole 221, intercepting a small amount of contaminants escaping from the tiny gap between the blocking plug 310 and the through hole 221. This achieves dual protection of sealing and airflow interception, ensuring the cleanliness of the seed crystal 510 during the cooking stage. It should be noted that the barrier plug and the insulation top wall form a locking fit structure, and the insulation top wall is made of carbon felt material specifically designed for high-temperature operating conditions. The carbon felt has a stable overall structure and possesses the characteristics of micro-compression buffering and localized yielding deformation. Under the high-temperature environment inside the furnace, the barrier plug is prone to thermal expansion. Relying on the micro-compression adaptability of the carbon felt itself, it can effectively buffer the changes in the fit dimensions caused by thermal expansion, avoiding hard compression and jamming between the barrier plug and the insulation top wall, ensuring that the barrier plug can move smoothly under traction and stably complete the action of disengaging from the through hole.

[0063] When the cooking process is completed, the seed crystal rod 500 is lowered. During the descent of the seed crystal rod 500, the tungsten wire rope 322 is tightened, pulling the blocking plug 310 upward and disengaging it from the through hole 221. At the same time, the blocking plug 310 moves along the guide groove on the insulation top wall 220 to prevent deviation. When the blocking plug 310 switches to the second state, it at least partially blocks the jet path of the corresponding nozzle 400, while the other nozzles 400 continue to jet argon. The originally symmetrical airflow field is broken, forming an asymmetrical airflow. After the through hole 221 is opened, the contaminants continuously generated by the melt in the crucible 600 and the contaminants accumulated above the insulation cavity 230 during the cooking stage will float upward under the action of thermal convection. When the contaminants rise to the area above the through hole 221, they will be forced to flow to the side by the asymmetrical airflow, away from the central axis of the through hole 221, to prevent the contaminants from contacting the descending seed crystal 510.

[0064] The seed crystal rod 500 continues to descend, passing through the open through-hole 221, and bringing the seed crystal 510 into the heat preservation cavity 230. It gradually approaches the alumina melt in the crucible 600. When the seed crystal 510 contacts the surface of the melt, the crystal pulling operation is completed. After the seed crystal rod 500 descends to its final position, the blocking plug 310 is suspended and will not block the jet from the nozzle 400. The jet airflow returns to a symmetrical and stable state, acting as an airflow barrier 410 to block the through-hole 221.

[0065] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0066] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A sapphire crystal growth furnace, characterized in that, include: The furnace body (100) has a furnace chamber (110) inside, and a seed crystal channel (120) is provided on the top of the furnace body (100) to allow the seed crystal rod (500) to pass through. A heat insulation structure (200) is located inside the furnace chamber (110). The heat insulation structure (200) is barrel-shaped and includes a heat insulation side wall (210) and a heat insulation top wall (220). The heat insulation side wall (210) and the heat insulation top wall (220) enclose a heat insulation cavity (230) for crystal growth. A through hole (221) is provided on the heat insulation top wall (220). The through hole (221) and the seed crystal channel (120) are located in the same vertical space. A blocking mechanism (300) is located inside the furnace chamber (110) and is used to block the through hole (221). The blocking mechanism (300) includes a blocking plug (310) having a degree of freedom of movement, and the blocking plug (310) can move in at least a first state and a second state: In the first state, the blocking plug (310) is engaged in the through hole (221) so that the through hole (221) is in a blocked state; In the second state, the blocking plug (310) disengages from the through hole (221) so that the through hole (221) is in the open state; The barrier plug (310) includes: Part 1 (311); The second part (312) is fixedly connected to the lower part of the first part (311), and the second part (312) is used to adsorb impurities that float to the surface. A transition space (111) is formed between the insulation top wall (220) of the insulation structure (200) and the inner top surface of the furnace body (100). The blocking mechanism (300) further includes a transmission assembly (320) located within the transition space (111), the transmission assembly (320) comprising: A drive wheel (321) is rotatably connected to the inner top surface of the furnace body (100), and the drive wheel (321) can rotate around an axis; A tungsten wire rope (322) is wound around the transmission wheel (321), and the first end of the tungsten wire rope (322) is fixedly connected to the seed crystal rod (500), and the second end of the tungsten wire rope (322) is fixedly connected to the blocking plug (310), so that when the seed crystal rod (500) descends, the blocking plug (310) is pulled away from the through hole (221) by the tungsten wire rope (322), so that the through hole (221) is opened; It also includes multiple sets of nozzles (400), which are disposed on the inner sidewall of the furnace body (100). The height of the nozzles (400) is higher than the plane of the heat-insulating top wall (220), and the nozzles (400) are disposed corresponding to the center of the through hole (221). The multiple sets of nozzles (400) are symmetrically arranged along the circumference of the through hole (221). The nozzles (400) are used to spray argon gas, and the spray direction is horizontally upward towards the through hole (221). The nozzle (400) has an air outlet height that is higher than the plane of the heat-insulating top wall (220) by a set distance, which is 1 / 6 to 5 / 6 of the height of the barrier plug (310). At least one of the nozzles (400) is arranged on the movement path of the blocking plug (310) when it switches from the first state to the second state; when the blocking plug (310) switches to the second state, it blocks the jet path of the nozzle (400), causing the upward pollutants to be guided to the side under the action of asymmetric airflow.

2. The sapphire crystal growth furnace according to claim 1, characterized in that, The first part (311) is tungsten or molybdenum; the second part (312) is an active tungsten or molybdenum porous body.

3. The sapphire crystal growth furnace according to claim 1, characterized in that, The heat-insulating top wall (220) is provided with a guide groove, which is used to guide and limit the movement of the blocking plug (310) so that the blocking plug (310) blocks the jet path of the nozzle (400) when it moves.

4. A method for preparing sapphire crystals using the sapphire crystal growth furnace as described in claim 1, characterized in that, include: Crystal growth raw materials are loaded into the crucible (600) inside the furnace, and the blocking plug (310) seals the through hole (221) of the heat preservation top wall (220) to carry out the cooking process; The seed crystal rod (500) is lowered, and the tungsten wire rope (322) drives the blocking plug (310) to disengage from the through hole (221), thereby opening the through hole (221); The seed crystal rod (500) continues to descend and extends into the crucible (600) to complete the crystal introduction.

5. A method for preparing sapphire crystals using the sapphire crystal growth furnace as described in claim 1, characterized in that, include: Crystal growth raw materials are loaded into the crucible (600) inside the furnace, and the blocking plug (310) seals the through hole (221) of the heat preservation top wall (220) to carry out the cooking process; The seed crystal rod (500) is controlled to descend, which drives the blocking plug (310) to disengage from the through hole (221) and block the nozzle (400), so that multiple nozzles (400) form an asymmetric airflow and guide the flow to the side. The seed crystal rod (500) continues to descend and extends into the crucible (600) to complete the crystal introduction.

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