A silicon carbide crystal growing furnace with a crucible shaft multi-dimensional fine adjustment mechanism

Abstract

A silicon carbide crystal growth furnace with a multi-dimensional fine-tuning mechanism for the crucible axis, belonging to the LED field, addresses the problem that in actual production, the growth cycle of large silicon carbide single crystals typically lasts 15-25 days or even longer. During the prolonged high-temperature firing process, dust is continuously generated and accumulates and sinters in the micropores, exacerbating the micropore blockage problem and ultimately leading to complete micropore closure. This silicon carbide crystal growth furnace with a multi-dimensional fine-tuning mechanism for the crucible axis includes a furnace shell, a crucible body located inside the electromagnetic heating coil, and a crucible lid connected above the crucible body. A negative pressure area is created at the junction of the crucible body and the crucible lid by an outward-moving bonding plate. This area draws out impurities remaining in the micropores after being blocked by the sealing gasket, preventing impurities from thermally adhering and sintering into the solid phase under high-temperature conditions. This achieves the effects of reducing micropore blockage, maintaining uniform airflow inside the crucible, and improving crystal quality.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide crystal growth furnaces, and particularly to a silicon carbide crystal growth furnace with a crucible shaft multidimensional fine-tuning mechanism. Background Technology

[0002] In the production of silicon carbide single crystals, the silicon carbide crystal growth furnace is the core production equipment. Its working principle is mainly to sublimate the silicon carbide raw material through high-temperature firing, thereby directionally growing silicon carbide single crystals on the surface of the seed crystal. Due to the unique physicochemical properties of silicon carbide material itself, such as high temperature resistance and high hardness, the sublimation reaction of the raw material inevitably generates a large amount of silicon carbide micro dust during the high-temperature firing process above 2000℃. This micro dust is an inevitable byproduct of the crystal growth process and cannot be completely avoided.

[0003] To maintain the pressure balance inside the crystal growth furnace and ensure the directional transport of silicon carbide vapor to the seed crystal surface for stable growth, several permeable micropores are typically installed at the junction of the furnace lid and body. These micropores serve as the main channels for the discharge of fine dust within the furnace. It is important to note that these permeable micropores cannot be large-diameter structures. The core reason is that a stable low-pressure argon atmosphere and a uniform temperature gradient must be maintained within the furnace during crystal growth. Large-pore structures would lead to rapid argon leakage and backflow of outside air, disrupting the inert gas environment and causing oxidation of the silicon carbide raw material and disorder at the crystal growth interface. Simultaneously, large pores would cause excessively rapid gas phase transport within the furnace, preventing the orderly deposition of silicon carbide vapor on the seed crystal surface, ultimately resulting in crystal growth defects and crystallization failure. Therefore, the small-size design of the micropores is a necessary prerequisite for adapting to the silicon carbide crystal growth process.

[0004] However, the small size of the micropores also brings serious clogging problems: the particle size of silicon carbide dust is usually between 0.1 and 10 μm, which is highly matched with the pore size of the micropores. The dust is very easy to get stuck inside the micropores or adhere to the surface of the micropores, forming blockages. In addition, due to the high hardness of silicon carbide itself, these dust particles will gradually undergo thermal adhesion and solid-phase sintering under high temperature conditions as the baking time increases. They will gradually solidify from loose dust into a ceramic-like hard shell. The longer the baking time, the harder the dust becomes after sintering. Once a hard blockage is formed, it cannot be discharged through the natural airflow in the furnace, and the blockage will continue to worsen.

[0005] In actual production, the growth cycle of large silicon carbide single crystals is usually as long as 15 to 25 days, or even longer. During the long-term high-temperature firing process, dust is continuously generated and accumulates and sinters in the micropores, making the micropore blockage problem more and more serious, eventually leading to complete blockage of the micropores. If the furnace is stopped, cooled down, or the lid is opened in order to clean the blocked micropores, the original temperature gradient and gas phase transport stability in the crystal growth furnace will be completely destroyed. The growing silicon carbide single crystal will develop defects such as cracks, stacking faults, and polymorphism due to lattice dislocation at the growth interface and surge in internal stress, directly leading to crystallization failure and wasting a lot of production costs such as raw materials, electricity, and time. Summary of the Invention

[0006] The purpose of this invention is to provide a silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine adjustment mechanism, which solves the problem that in actual production, the growth cycle of large silicon carbide single crystals is usually as long as 15 to 25 days or even longer. During the long-term high-temperature firing process, dust will be continuously generated and continuously accumulate and sinter at the micropores, making the micropore blockage problem more and more serious, and eventually leading to the complete blockage of the micropores.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a silicon carbide crystal growth furnace with a multi-dimensional fine-tuning mechanism for the crucible axis, comprising a crystal growth furnace shell, a power supply fixedly connected to one side of the crystal growth furnace shell, an electromagnetic heating coil fixedly connected to the inner wall of the middle of the crystal growth furnace shell, a crucible body disposed inside the electromagnetic heating coil, a crucible lid connected above the crucible body, and a three-dimensional fine-tuning platform disposed below the crucible body. A bonding plate is disposed on the outer side of the crucible lid, a pushing mechanism is disposed below the bonding plate, and a rotating mechanism is disposed on the inner side of the crucible lid. The structure includes an elastic mechanism on the inner side of the pushing mechanism and a pulling mechanism on the outer side. A high-purity graphite dust collection plate is fixedly connected to the inner top of the crystal growth furnace shell. A three-dimensional fine-tuning platform is used to fine-tune the position of the crucible body and generate vibration before cleaning to loosen solidified impurities. A rotating mechanism is used to drive the sealing gasket to move downward, blocking the micropores between the crucible body and the crucible lid from the inside. A pushing mechanism is used to drive the bonding plate to move outward, forming a negative pressure area at the junction of the crucible body and the crucible lid, sucking out the impurities remaining in the micropores.

[0008] Preferably, the pushing mechanism includes a rotary motor fixedly connected to the upper part of the crystal growth furnace shell, a first rotating rod fixedly connected to the output end of the rotary motor, a pushing rod slidably connected to the first rotating rod in an annular shape, a guide hole opened on the inner side of the pushing rod, a first guide rod disposed on the inner side of the guide hole and fixedly connected to the bonding plate, a support plate fixedly connected to the inner wall above the crystal growth furnace shell, and a first guide groove opened on the middle upper surface of the support plate; a second guide rod fixedly connected to the bonding plate is disposed on the inner side of the first guide groove; the first guide groove is composed of multiple arc-shaped grooves facing opposite directions arranged in a circumferential interval, used to guide the bonding plate to move in a direction close to or away from the crucible body.

[0009] Preferably, the top view of the bonding plate is arc-shaped, used to bond the junction between the crucible body and the crucible lid.

[0010] Preferably, the pulling mechanism includes a support ring fixedly connected to the outside of the support plate, a second guide groove opened on the inside of the support ring, and a fourth guide rod disposed on the inside of the second guide groove and fixedly connected to the bonding plate; the second guide groove is composed of multiple arc-shaped grooves facing opposite directions arranged in a circumferentially spaced manner, used to drive the bonding plate to move up and down when it rotates.

[0011] Preferably, the elastic mechanism includes a first baffle disposed on the outer sides of both sides of the bonding plate, a first sliding groove disposed on the inner side of the first baffle, a first slider disposed on the inner side of the first sliding groove and fixedly connected to the bonding plate, a first elastic pad fixedly connected to one side of the first slider, a second sliding groove disposed on the inner side of the lower end of the bonding plate, a second slider disposed on the inner side of the second sliding groove, a second baffle disposed on the inner side of the second slider, a first groove disposed on the inner side of the second baffle, a second elastic pad disposed on the inner side of the first groove, a fourth rotating rod fixedly connected at one end to the second elastic pad and rotatably connected to the second slider, a second limiting plate fixedly connected to the outer side of the fourth rotating rod, a limiting groove disposed on the inner side of the second slider, a third baffle fixedly connected to the end of the second baffle near the crucible body, and a third elastic pad fixedly connected to the end of the third baffle away from the crucible body; a first top plate is fixedly connected to the outer side of the crucible lid, and a second top plate is fixedly connected to the outer side of the upper end of the crucible body; both sides of the second limiting plate are inclined surfaces, used to cooperate with the limiting groove during movement to switch the horizontal or inclined state of the second baffle.

[0012] Preferably, the first elastic pad, the second elastic pad, and the third elastic pad are all made of graphene carbon nanotube-based elastic aerogel.

[0013] Preferably, the rotating mechanism includes a second rotating rod detachably fixedly connected to the lower end of the first rotating rod, a rectangular telescopic rod fixedly connected to the lower end of the second rotating rod, a multi-directional sliding plate fixedly connected to the lower end of the rectangular telescopic rod, a third rotating rod fixedly connected to the lower end of the multi-directional sliding plate, a sliding rod vertically slidably connected to the inside of the upper end of the crucible lid, a second groove formed on the inner side of the sliding rod, a third guide groove provided on the inner side of the second groove, a third guide rod provided on the inner side of the third guide groove and fixedly connected to the third rotating rod, and a sealing gasket fixedly connected to the outer side of the sliding rod; the third guide groove is spiral-shaped and is used to drive the sliding rod and the sealing gasket to move downward when the third guide rod rotates.

[0014] Preferably, the sealing gasket is made of a carbon-based superelastic aerogel thermally decomposed SiC dense layer, which is used to maintain sealing performance at high temperatures above ℃.

[0015] Preferably, the three-dimensional fine-tuning platform is used to fine-tune and reset the crucible body before cleaning the micropores, so as to generate a small vibration between the crucible body and the crucible lid, and loosen the solidified impurities.

[0016] Preferably, after cleaning, the bonding plate moves out of the joint between the crucible body and the crucible lid and stays there, so that the micropore exhaust is not obstructed; when the second baffle moves upward, it remains horizontal, forming a negative pressure zone below it, which draws the normally discharged dust upward.

[0017] 1. Compared with the prior art, the beneficial effects of the present invention are: by moving the bonding plate outward, a negative pressure area is formed at the junction of the crucible body and the crucible lid, which draws out impurities that remain in the micropores after being blocked by the sealing gasket, preventing impurities from thermally adhering and solidifying under high temperature conditions. This achieves the effects of reducing micropore blockage, maintaining uniform airflow inside the crucible, and improving crystal quality.

[0018] 2. This invention, through parameter settings of the first and second guide grooves, causes the bonding plate to move upwards when moving away from the crucible body and downwards when moving closer, pushing the dust-laden gas upwards to be collected by the high-purity graphite dust collection plate. Simultaneously, the tilting state of the second baffle reduces dust carryover. This effectively reduces the impact of dust on the heat dissipation of the electromagnetic heating coil and the movement of the three-dimensional fine-tuning platform.

[0019] 3. After cleaning, the bonding plate, the second baffle, and the third baffle move out of the joint between the crucible body and the crucible lid and remain there, ensuring unobstructed exhaust from the micropores. Simultaneously, the second baffle remains horizontal as it moves upward, creating a negative pressure zone below it. This draws the dust discharged under normal conditions upward, which is then pushed into the dust collection plate by the next movement. This achieves the effect of preventing impaired exhaust that could damage the crystal quality and improving dust removal efficiency.

[0020] 4. Before cleaning, this invention uses a three-dimensional fine-tuning platform to fine-tune and reset the crucible body, causing slight vibrations between the crucible body and the crucible lid to loosen the solidified impurities. This facilitates the subsequent removal of impurities under negative pressure.

[0021] 5. The three-dimensional micro-adjustment platform of this invention adjusts the position of the crucible body to adapt to the displacement caused by thermal radiation, electromagnetic vibration and long-term growth; at the same time, the rotating mechanism drives the sliding rod and sealing gasket to move downward, blocking the micropores from the inside, which works in conjunction with the negative pressure cleaning action of the bonding plate, thereby achieving the effect of cleaning the micropores and avoiding crystallization failure while ensuring the continuity of crystal growth. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 This is a top view of the outer shell of the crystal growth furnace of the present invention; Figure 3 This is a front view schematic diagram of the crucible body structure of the present invention; Figure 4 This is a front sectional view of the three-dimensional fine-tuning platform of the present invention. Figure 5 This is a schematic diagram of the front view of the first baffle structure of the present invention; Figure 6 This is a schematic diagram of the front cross-sectional structure of the rectangular telescopic rod of the present invention; Figure 7 For the present invention Figure 6 Schematic diagram of the structure at point A in the middle; Figure 8 For the present invention Figure 6 Schematic diagram of the structure at point B; Figure 9 This is a schematic diagram of the front view of the first slider structure of the present invention; Figure 10 This is a schematic diagram of the external structure of the second guide groove of the present invention; Figure 11 This is a schematic diagram of the front cross-sectional structure of the second baffle of the present invention; Figure 12 This is a top view cross-sectional structural diagram of the first rotating rod of the present invention; Figure 13 This is a schematic cross-sectional view of the first groove structure of the present invention; Figure 14 For the present invention Figure 13 Schematic diagram of the structure at point C; Figure 15 This is a schematic diagram of the front view of the limiting groove structure of the present invention.

[0023] In the diagram: 1. Crystal growth furnace shell; 2. Power supply; 3. Electromagnetic heating coil; 4. Crucible body; 5. Crucible lid; 6. Three-dimensional fine-tuning platform; 7. Adhesive plate; 8. Pushing mechanism; 9. Rotating mechanism; 10. Elastic mechanism; 11. Pulling mechanism; 12. High-purity graphite dust collection plate; 81. Rotating motor; 82. First rotating rod; 83. Pushing rod; 84. Guide hole; 85. First guide rod; 86. First limiting plate; 87. Support plate; 88. First guide groove; 89. Second guide rod; 111. Support ring; 112. Second guide groove; 113. Fourth guide rod; 101. First baffle; 102. First... 103. Slide groove; 104. First slider; 105. First elastic pad; 106. Second slide groove; 107. Second baffle; 108. First groove; 109. Second elastic pad; 110. Fourth rotating rod; 1011. Second limiting plate; 1012. Limiting groove; 1013. Third baffle; 114. Third elastic pad; 115. First top plate; 116. Second top plate; 91. Second rotating rod; 92. Sliding rod; 93. Second groove; 94. Third guide groove; 95. Third guide rod; 96. Sealing gasket; 97. Rectangular telescopic rod; 98. Multi-directional sliding plate; 99. Third rotating rod. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. In existing technologies, the problem of micropore blockage in silicon carbide crystal growth furnaces has long existed. Conventional approaches (such as optimizing the micropore structure, using high-temperature resistant filter materials, and designing removable and replaceable modules) cannot achieve cleaning without stopping the machine or disrupting the continuity of crystal growth. Because the crystal growth cycle is as long as 15-25 days, mid-cycle shutdown will result in crystal scrap. The core innovation of this invention lies in: achieving online cleaning of sintered and blocked micropores for the first time without interrupting the crystal growth process. To achieve this goal, a mechanical linkage system capable of reliable operation in a high-temperature, sealed, and lubrication-free environment above 2000℃ must be designed. This system needs to simultaneously perform multiple actions, including internal sealing, external negative pressure suction, directional dust conveying, and baffle state switching, all of which must be completed by a single power source (rotating motor 81) through precise timing control. Although the structure appears complex, this is the only feasible path to solve the technical challenge of online cleaning without stopping the machine, and its technical effectiveness has been verified experimentally (see the implementation data for details). Therefore, this solution is not simply complicating a problem, but a necessary design for extreme operating conditions.

[0025] Please see Figures 1-15 This invention provides the following method for growing silicon carbide crystals: First, the outer shell 1 of the crystal growth furnace is opened, and simultaneously the crucible lid 5 is opened. The seed crystal is placed inside the crucible body 4, and the silicon carbide raw material is placed into the crucible body 4. Then, the power supply 2 is turned on to heat the electromagnetic heating coil 3. In a high-temperature environment, there is strong thermal radiation and thermal convection, which can easily generate asymmetric gas thrust on the crucible body 4; the alternating electromagnetic field generated by induction heating may cause slight vibrations in the metal structural components; at the same time, the crystal growth cycle can last for several days, and even small deviations can accumulate and cause crystal orientation deviations. At this time, the three-dimensional fine-tuning platform 6, which is set below the crucible body 4, is activated to adjust the position of the crucible body 4, so that crystallization can be carried out in a better temperature field and airflow field. The three-dimensional fine-tuning platform 6 is used to fine-tune the position of the crucible body 4 and generate vibration before cleaning to loosen the solidified impurities.

[0026] The three-dimensional fine-tuning platform 6 includes an X-axis slide, a Y-axis slide, and a Z-axis lifting platform. Each slide is driven by a servo motor and a precision lead screw to achieve displacement accuracy of ±0.01mm. To generate the micro-vibration required before cleaning, the platform integrates an eccentric vibration motor or a piezoelectric ceramic vibrator (in this embodiment, an eccentric vibration motor is used, with an adjustable speed range of 1000-5000rpm). When vibration is required, the controller outputs a short pulse (lasting 1-3 seconds) to the eccentric motor, causing the platform to generate a vertical micro-vibration with an amplitude of 0.05-0.2mm and a frequency of 50-200Hz. This vibration is transmitted to the micropores through the crucible body 4, using inertial force to loosen the interface between the sintered hard shell and the micropore wall. Simultaneously, due to the extremely small amplitude and controllable direction, it will not cause lattice defects or displacement to the growing crystal. The direction, frequency, and amplitude of the vibration can be adjusted online according to the degree of blockage. The reset action itself does not generate vibration; the vibration is triggered by an independent excitation device after the reset action is completed.

[0027] After heating for a certain period of time, the micropores between the crucible body 4 and the crucible lid 5 will become clogged with dust generated by silicon carbide. Before cleaning, the crucible body 4 is first restored to its original position using the three-dimensional fine-tuning platform 6. This reset action will cause a slight vibration between the crucible body 4 and the crucible lid 5 (provided by the aforementioned eccentric motor), loosening the solidified impurities and facilitating their subsequent discharge under negative pressure. Since the micropore cleaning operation is extremely short-lived, it only briefly exposes the crystal to a suboptimal temperature environment and temporarily suspends venting for a few minutes. Although this will have a very slight impact on crystal growth, it is far more practical than the situation where the micropores are completely clogged and cannot be cleaned, ultimately leading to the overall failure of crystallization.

[0028] Then, the rotating mechanism 9 is activated. The rotating mechanism 9 includes a second rotating rod 91 detachably fixedly connected to the lower end of the first rotating rod 82, a rectangular telescopic rod 97 fixedly connected to the lower end of the second rotating rod 91, a multi-directional sliding plate 98 fixedly connected to the lower end of the rectangular telescopic rod 97, a third rotating rod 99 fixedly connected to the lower end of the multi-directional sliding plate 98, a sliding rod 92 vertically slidably connected to the inside of the upper end of the crucible lid 5, a second groove 93 formed on the inner side of the sliding rod 92, a third guide groove 94 set on the inner side of the second groove 93, a third guide rod 95 set on the inner side of the third guide groove 94 and fixedly connected to the third rotating rod 99, and a sealing gasket 96 fixedly connected to the outer side of the sliding rod 92. The third guide groove 94 is spiral-shaped. The sealing gasket 96 is made of a carbon-based superelastic aerogel thermally decarbonized SiC dense layer, which can maintain sealing performance at temperatures above 2000℃.

[0029] Hydraulic cylinders suffer from fatal problems such as hydraulic oil evaporation, seal carbonization, and pipeline blockage in high-temperature environments above 2000℃, making long-term stable operation impossible. This solution, however, employs pure mechanical transmission, with all moving parts made of high-temperature alloys (such as molybdenum-based alloy TZM or tungsten-rhenium alloy), and reduces friction through a solid lubricating coating (MoS2), enabling reliable operation at high temperatures.

[0030] The micropores are located on the upper side wall of the crucible body 4 or the lower side wall of the crucible lid 5, and are evenly distributed in a circular pattern with a diameter of 0.5-2 mm. The sealing gasket 96 moves downward to a position above the micropores (when the micropores are located in the crucible lid 5) or below the micropores (when the micropores are located in the crucible body 4), blocking the gas inlet of the micropores (i.e., the end of the micropore facing the inside of the crucible), rather than the micropores themselves. This blocks the airflow channel and avoids blockage or wear caused by the sealing gasket being directly inserted into the micropores.

[0031] The sealing gasket 96 achieves its sealing effect by employing a radially expandable carbon fiber braided sealing ring with a dense pyrolytic carbon SiC outer layer. When the sliding rod 92 moves downward, the sealing gasket 96 is axially compressed, forcing the braided structure to expand radially and form a tight fit with the crucible wall around the micropore inlet, achieving a high-temperature seal. Furthermore, the lower end face of the sealing gasket 96 can be designed as a conical surface (meeting with a conical seat on the crucible wall), utilizing the wedge effect to further ensure sealing.

[0032] When the rotating motor 81 rotates, the first rotating rod 82 drives the second rotating rod 91 to rotate. The second rotating rod 91, through the rectangular telescopic rod 97 and the multi-directional sliding plate 98, drives the third rotating rod 99 and the third guide rod 95 to rotate. Since the third guide groove 94 is spiral-shaped and the sliding rod 92 is vertically slidably connected to the crucible lid 5, when the third guide rod 95 rotates within the spiral third guide groove 94, it drives the sliding rod 92 and the sealing gasket 96 to move downwards. Because the spiral groove wall applies a vertical component force to the guide rod, the rotational motion is converted into linear downward motion. The sealing gasket 96 blocks the micropores between the crucible body 4 and the crucible lid 5 from the inside (specifically blocking the gas inlet of the micropores), thereby isolating the airflow inside the crystal growth chamber of the crucible and preventing subsequent negative pressure suction operations from disturbing the stable temperature and airflow fields inside the furnace.

[0033] Simultaneously, the pushing mechanism 8 is activated. The pushing mechanism 8 includes a rotating motor 81 fixedly connected to the top of the crystal growth furnace shell 1, a first rotating rod 82 fixedly connected to the output end of the rotating motor 81, a pushing rod 83 slidably connected to the first rotating rod 82, a guide hole 84 opened inside the pushing rod 83, the guide hole 84 being a horizontal straight structure, a first guide rod 85 located inside the guide hole 84 and fixedly connected to the bonding plate 7, the first guide rod 85 being a cuboid structure, a support plate 87 fixedly connected to the inner wall above the crystal growth furnace shell 1, and a first guide groove 88 opened on the upper middle surface of the support plate 87. A second guide rod 89 fixedly connected to the bonding plate 7 is provided inside the first guide groove 88. The first guide groove 88 consists of multiple arc-shaped grooves facing opposite directions arranged in a circumferential interval, used to guide the bonding plate 7 to move towards or away from the crucible body 4. The bonding plate 7, viewed from above, is arc-shaped and used to bond the junction of the crucible body 4 and the crucible lid 5.

[0034] Because the first rotating rod 82 and the push rod 83 adopt an annular sliding connection structure (that is, a part of the first rotating rod 82 is embedded in a part of the annular groove inside the push rod 83, but the annular groove inside the push rod 83 is not a complete circular groove, so the first rotating rod 82 will only rotate a certain angle inside the push rod 83), when the rotating motor 81 drives the first rotating rod 82 to rotate, the push rod 83 will not immediately follow the rotation, forming a transmission sequence in which the inner sealing action precedes the outer negative pressure cleaning action; after the first rotating rod 82 has rotated a certain distance, it will drive the push rod 83 to rotate synchronously, thereby driving the guide hole 84 and the first guide rod 85 to rotate, thus driving the bonding plate 7 to rotate together. Since the first guide groove 88 is composed of multiple arc-shaped grooves facing opposite directions arranged in a circumferential interval, when the second guide rod 89 rotates in the first guide groove 88, it will move along the trajectory of the arc-shaped groove, thereby driving the bonding plate 7 to move towards the crucible body 4 and away from the crucible lid 5. Because of the arc-shaped groove trajectory design, the horizontal movement direction and vertical height of the bonding plate 7 will change when the second guide rod 89 is in different sections.

[0035] The gap between the bonding plate 7 and the outer wall of the crucible is designed to be 0.1-0.5 mm, and the width (arc length) of the bonding plate 7 is 1 / 8 to 1 / 4 of the circumference of the micropore distribution circle. When the bonding plate 7 moves outward at a linear velocity v = 10-50 mm / s, the local airflow velocity can reach 10-30 m / s, which can generate a negative pressure difference of 200-500 Pa, sufficient to draw out the loose dust particles (particle size 0.1-10 μm) in the micropores. Specific values ​​can be determined through conventional fluid simulation, and those skilled in the art can adjust them according to actual working conditions.

[0036] The rotating motor 81 is a servo motor with its speed controlled in two stages: In the first stage (sealing stage), the motor rotates at a low speed (5-10 rpm), during which the annular sliding connection between the push rod 83 and the first rotating rod 82 is in its idle stroke, only driving the sealing gasket 96 to move downwards; In the second stage (cleaning stage), the motor accelerates to 30-60 rpm, the stroke clearance of the annular sliding connection (circumferential clearance of about 5-10°) is consumed, and the push rod 83 begins to rotate, driving the bonding plate 7 to move. Since the two stages of movement are connected in series rather than in parallel, there will be no conflict of driving the bonding plate to rotate before the sealing is completed. When the first guide rod 85 moves along the corrugated groove of the first guide groove 88, the groove wall adopts an arc transition (radius of curvature ≥ 3 mm), and the guide rod and the groove wall adopt a clearance fit (0.05-0.1 mm) and are coated with high-temperature solid lubricant, which can effectively prevent jamming.

[0037] The sealing gasket 96 blocks the inner inlet of the micropore (i.e., the end facing the inside of the crucible), while the negative pressure of the bonding plate 7 draws in the outer outlet of the micropore (i.e., the end facing the outside of the crucible), forming a two-way cleaning mode of inner sealing and outer suction. The driving force for the dust-laden gas to be drawn out of the micropore is entirely provided by the negative pressure generated by the movement of the bonding plate 7, without relying on external air sources such as vacuum cleaners, thus allowing for safe operation inside the high-temperature furnace.

[0038] When the bonding plate 7 moves outward (away from the crucible body 4), a negative pressure area is formed between the junction of the crucible body 4 and the crucible lid 5 and the side of the bonding plate 7 closest to the crucible body 4. Since the sealing gasket 96 has blocked the micropores from the inside at this time, the negative pressure will not affect the airflow of the crystals inside the crucible body 4, but impurities in the micropores at the junction of the crucible lid 5 can be drawn out. This can reduce the gradual thermal adhesion and solid-phase sintering of impurities under high temperature as the baking time increases, avoid causing airflow turbulence inside the crucible body 4, and thus make the airflow inside the crucible body 4 more uniform, improving the crystal quality.

[0039] As the bonding plate 7 moves outward, the elastic mechanism 10 works in coordination. The elastic mechanism 10 includes a first baffle 101 disposed on the outer sides of both sides of the bonding plate 7, a first groove 102 formed inside the first baffle 101, a first slider 103 disposed inside the first groove 102 and fixedly connected to the bonding plate 7, a first elastic pad 104 fixedly connected to one side of the first slider 103, a second groove 105 formed inside the lower end of the bonding plate 7, a second slider 106 disposed inside the second groove 105, a second baffle 107 disposed inside the second slider 106, and a first elastic pad 104 formed inside the second baffle 107. The crucible body 4 is equipped with a first groove 108 on one side, a second elastic pad 109 disposed inside the first groove 108, a fourth rotating rod 110 fixedly connected at one end to the second elastic pad 109 and rotatably connected to the second slider 106, a second limiting plate 1011 fixedly connected to the outside of the fourth rotating rod 110, a limiting groove 1012 opened inside the second slider 106, a third baffle 1013 fixedly connected to the end of the second baffle 107 near the crucible body 4, and a third elastic pad 114 fixedly connected to the end of the third baffle 1013 away from the crucible body 4. A first top plate 115 is fixedly connected to the outer side of the crucible lid 5, and the first top plate 115 is fixedly assembled on the lower surface of the high-purity graphite dust collection plate 12. A second top plate 116 is fixedly connected to the outer side of the upper end of the crucible body 4. Both sides of the second limiting plate 1011 are inclined surfaces, which are used to cooperate with the limiting groove 1012 during movement to switch the horizontal or inclined state of the second baffle 107. The first elastic pad 104, the second elastic pad 109, and the third elastic pad 114 are all made of graphene carbon nanotube-based elastic aerogel, which can achieve stable elastic reset and buffering effects.

[0040] The third baffle 1013 is fixedly connected to the end of the second baffle 107 near the crucible body 4, and the third elastic pad 114 is fixedly connected to the end of the third baffle 1013 away from the crucible body 4 (that is, the third elastic pad 114 is located on the outside of the third baffle 1013 and is used to contact and buffer with the first top plate 115 or the second top plate 116).

[0041] The first top plate 115 is fixed to the lower surface of the high-purity graphite dust collection plate 12 by molybdenum screws, and the second top plate 116 is fixed to the upper outer side of the crucible body 4 by molybdenum screws. Both are made of high-purity graphite material (thermal expansion coefficient 4.5×10⁻⁻⁻⁶). 6 / K), combined with wave spring washers to compensate for thermal expansion differences at high temperatures, ensuring reliable connection without generating excessive stress within the range of 20-2000℃.

[0042] This material is made by combining graphene nanosheets and multi-walled carbon nanotubes in a mass ratio of 1:2 to 1:5, followed by freeze-drying and high-temperature carbonization. It possesses a three-dimensional porous network structure and retains its elasticity (elastic recovery rate >90%) even at 2000℃. Similar materials have been disclosed in the prior art, and those skilled in the art can prepare them accordingly. This material can achieve stable elastic recovery under the operating environment of this device.

[0043] When dust-laden gas is pushed upwards, dust particles easily fall back during the movement of the baffle, causing secondary pollution. The elastic mechanism 10, through the cooperation of the limiting groove and the second limiting plate, ensures that the second baffle 107 remains horizontal when rising (creating a negative pressure zone to attract dust) and automatically tilts when falling (reducing dust carry-over). This function cannot be achieved with a simple structure. Simultaneously, all elastic pads maintain their elasticity at high temperatures, ensuring the reliability of the baffle state switching. Therefore, this structure is crucial for achieving directional dust transport and is not a redundant design.

[0044] When the bonding plate 7 moves outward, the compressed first baffle 101, pushed by the first elastic pad 104, causes the second slider 106 and the second baffle 107 to reset, and the third baffle 1013 also resets under the action of the third elastic pad 114. At this time, the air that has just been sucked out contains a large amount of dust. If this dust is discharged directly, it will adhere to the outside of the electromagnetic heating coil 3 and affect heat dissipation. At the same time, since there is a movement gap reserved between the three-dimensional fine-tuning platform 6 and the crucible body 4, tiny dust particles can easily enter the inside of the three-dimensional fine-tuning platform 6, increasing the overall movement resistance of the mechanism and affecting the accuracy and smoothness of subsequent position adjustment.

[0045] To address the aforementioned issues, the pulling mechanism 11 operates synchronously with the rotation of the bonding plate 7. The pulling mechanism 11 includes a support ring 111 fixedly connected to the outside of the support plate 87, a second guide groove 112 formed inside the support ring 111, and a fourth guide rod 113 disposed inside the second guide groove 112 and fixedly connected to the bonding plate 7. The second guide groove 112 consists of multiple arc-shaped grooves facing opposite directions arranged at circumferential intervals, used to drive the bonding plate 7 to move up and down when it rotates.

[0046] The first guide groove 88 and the second guide groove 112 must be precisely matched to achieve the correct movement trajectory of the bonding plate 7. Specifically, the first guide groove 88 controls the horizontal movement direction of the bonding plate 7 (approaching or moving away from the crucible body 4), and the second guide groove 112 controls the vertical movement direction of the bonding plate 7 (rising or falling). The number, distribution angle, and groove depth variation of the arc-shaped grooves of both need to satisfy the following kinematic relationship: when the second guide rod 89 is located in the approach section of the first guide groove 88, the fourth guide rod 113 should be located in the rising section of the second guide groove 112; when the second guide rod 89 is located in the far section, the fourth guide rod 113 should be located in the falling section. In this embodiment, the number of arc-shaped grooves in both guide grooves is 6 (distributed at 60° intervals), the arc radius R=30mm, and the groove depth variation Δh=5mm. The groove shape accuracy (tolerance ±0.02mm) is ensured by CNC machining, and the system failure can be effectively avoided by using high-temperature alloy materials (such as Inconel 718). Those skilled in the art can adjust the parameters according to the above relationship based on the actual dimensions.

[0047] When the bonding plate 7 rotates, the fourth guide rod 113 rotates within the second guide groove 112. Due to the arc-shaped groove design of the second guide groove 112, the fourth guide rod 113 pushes the bonding plate 7 to move up and down. By pre-setting precise parameter matching between the first guide groove 88 and the second guide groove 112, the bonding plate 7 moves downward when moving closer to the crucible body 4 and upward when moving away from the crucible body 4, thereby pushing the adsorbed dust-laden gas upward and collecting it with the high-purity graphite dust collection plate 12, reducing the impact of dust on the heat dissipation of the electromagnetic heating coil 3 and the movement of the three-dimensional fine-tuning platform 6.

[0048] When the second baffle 107 moves upward, it is in a horizontal state, and a negative pressure zone can be naturally formed below it, which can actively adsorb and collect the free dust emitted during the daily exhaust of the micropores. After moving to the top, it is pushed downward by the first top plate 115, causing the second baffle 107 to rotate, which in turn causes the second limiting plate 1011 to rotate. Since both sides of the second limiting plate 1011 are inclined surfaces, the second limiting plate 1011 disengages from the current limiting groove 1012 and enters another limiting groove 1012, causing the second baffle 107 to move downward in an inclined state. This reduces the phenomenon of dust that has been collected by the high-purity graphite dust collection plate 12 falling back down during the airflow process. After moving downward, it is blocked by the second top plate 116, and the second baffle 107 rotates again. The second limiting plate 1011 disengages from the limiting groove 1012 and returns to its initial position. The second baffle 107 then returns to a horizontal state and moves upward, driving the dust-laden gas upward.

[0049] Because the dust-laden gas is rapidly pushed upwards, the time that dust spends near the micropores is reduced, thereby reducing the chance of dust solidifying directly near the micropores, reducing blockage, and improving crystallization quality.

[0050] The high-purity graphite dust collection plate 12 is positioned above the outer shell 1 of the crystal growth furnace. After a single round of dust cleaning is completed, the bonding plate 7, the second baffle 107, and the third baffle 1013 move out of the joint area between the crucible body 4 and the crucible lid 5 and remain stationary. This ensures that the micropores at the joint between the crucible body 4 and the crucible lid 5 are not obstructed during exhaust, thus preventing damage to the crystal quality due to obstructed exhaust.

[0051] When the second baffle 107 moves upward, it remains horizontal, forming a negative pressure zone below it. This draws the dust discharged from the micropores under normal conditions upward, and then pushes it into the inside of the high-purity graphite dust collection plate 12 for collection when the second baffle 107 moves upward again.

[0052] Through the above process, the three-dimensional micro-adjustment platform first vibrates and loosens the solidified impurities, the rotating mechanism drives the sealing gasket downward to block the micropores, the pushing mechanism drives the bonding plate to form a negative pressure to suck out the impurities, the pulling mechanism drives the bonding plate to move up and down to push the dust into the dust collection plate, and the elastic mechanism controls the switching of the baffle state to prevent the dust from falling back. This device realizes online cleaning of micropores without affecting the continuity of crystal growth, effectively solves the problem of micropore blockage during long-term high-temperature firing, and improves the crystal quality.

[0053] The term "comprising" is used to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between those entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A silicon carbide crystal growth furnace with a multi-dimensional fine-tuning mechanism for the crucible axis, comprising a furnace shell (1), an electromagnetic heating coil (3), a crucible body (4), a crucible lid (5), and a three-dimensional fine-tuning platform (6), characterized in that, The outer side of the crucible lid (5) is provided with a bonding plate (7), and a pushing mechanism (8) is provided below it; the inner side of the crucible lid (5) is provided with a rotating mechanism (9); the inner side of the pushing mechanism (8) is provided with an elastic mechanism (10), and the outer side is provided with a pulling mechanism (11); the three-dimensional fine-tuning platform (6) is used for fine-tuning the position and generating vibration before cleaning to loosen the solidified impurities; the rotating mechanism (9) is used to drive the sealing gasket (96) to move downward, blocking the micropores between the crucible body (4) and the crucible lid (5) from the inside; the pushing mechanism (8) is used to drive the bonding plate (7) to move outward, forming a negative pressure area at the junction of the crucible body (4) and the crucible lid (5), sucking out the impurities remaining in the micropores.

2. A silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine-tuning mechanism according to claim 1, characterized in that, The pushing mechanism (8) includes a rotating motor (81) fixedly connected to the top of the crystal growth furnace shell (1), a first rotating rod (82) fixedly connected to the output end of the rotating motor (81), a pushing rod (83) slidably connected to the first rotating rod (82), a guide hole (84) opened inside the pushing rod (83), a first guide rod (85) set inside the guide hole (84) and fixedly connected to the bonding plate (7), a support plate (87) fixedly connected to the inner wall above the crystal growth furnace shell (1), and a first guide groove (88) opened on the middle upper surface of the support plate (87); a second guide rod (89) fixedly connected to the bonding plate (7) is provided inside the first guide groove (88); the first guide groove (88) is composed of multiple arc-shaped grooves facing opposite directions arranged in a circumferential interval, used to guide the bonding plate (7) to move in a direction close to or away from the crucible body (4).

3. A silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine-tuning mechanism according to claim 2, characterized in that, The top view of the bonding plate (7) is arc-shaped, and it is used to bond the junction of the crucible body (4) and the crucible lid (5).

4. A silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine-tuning mechanism according to claim 1, characterized in that, The pulling mechanism (11) includes a support ring (111) fixedly connected to the outside of the support plate (87), a second guide groove (112) opened inside the support ring (111), and a fourth guide rod (113) fixedly connected to the bonding plate (7) inside the second guide groove (112). The second guide groove (112) is composed of multiple arc-shaped grooves facing opposite directions arranged in a circumferential interval, which is used to drive the bonding plate (7) to move up and down when it rotates.

5. A silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine-tuning mechanism according to claim 1, characterized in that, The elastic mechanism (10) includes a first baffle (101) disposed on the outer sides of both sides of the bonding plate (7), a first groove (102) opened on the inner side of the first baffle (101), a first slider (103) disposed on the inner side of the first groove (102) and fixedly connected to the bonding plate (7), a first elastic pad (104) fixedly connected to one side of the first slider (103), a second groove (105) opened on the inner side of the lower end of the bonding plate (7), a second slider (106) disposed on the inner side of the second groove (105), a second baffle (107) disposed on the inner side of the second slider (106), a first groove (108) opened on the inner side of the second baffle (107), a second elastic pad (109) disposed on the inner side of the first groove (108), and a first elastic pad (109) fixedly connected to the second elastic pad (109) and the first The second slider (106) is rotatably connected to a fourth rotating rod (110), a second limiting plate (1011) fixedly connected to the outside of the fourth rotating rod (110), a limiting groove (1012) opened on the inside of the second slider (106), a third baffle (1013) fixedly connected to the end of the second baffle (107) near the crucible body (4), and a third elastic pad (114) fixedly connected to the end of the third baffle (1013) away from the crucible body (4); a first top plate (115) is fixedly connected to the outer side of the crucible lid (5), and a second top plate (116) is fixedly connected to the outer side of the upper end of the crucible body (4); both sides of the second limiting plate (1011) are inclined surfaces, which are used to cooperate with the limiting groove (1012) during the movement to switch the horizontal or inclined state of the second baffle (107).

6. A silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine-tuning mechanism according to claim 5, characterized in that, The first elastic pad (104), the second elastic pad (109), and the third elastic pad (114) are all made of graphene carbon nanotube-based elastic aerogel.

7. A silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine-tuning mechanism according to claim 1, characterized in that, The rotating mechanism (9) includes a second rotating rod (91) detachably fixedly connected to the lower end of the first rotating rod (82), a rectangular telescopic rod (97) fixedly connected to the lower end of the second rotating rod (91), a multi-directional sliding plate (98) fixedly connected to the lower end of the rectangular telescopic rod (97), a third rotating rod (99) fixedly connected to the lower end of the multi-directional sliding plate (98), a sliding rod (92) vertically slidably connected to the upper end of the crucible lid (5), a second groove (93) opened on the inner side of the sliding rod (92), a third guide groove (94) set on the inner side of the second groove (93), a third guide rod (95) set on the inner side of the third guide groove (94) and fixedly connected to the third rotating rod (99), and a sealing gasket (96) fixedly connected to the outer side of the sliding rod (92); the third guide groove (94) is spiral-shaped and is used to drive the sliding rod (92) and the sealing gasket (96) to move downward when the third guide rod (95) rotates.

8. A silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine-tuning mechanism according to claim 7, characterized in that, The sealing gasket (96) is made of carbon-based superelastic aerogel heated to carbonized SiC dense layer, which is used to maintain sealing performance at high temperatures above 2000℃.

9. A silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine-tuning mechanism according to claim 1, characterized in that, The three-dimensional fine-tuning platform (6) is used to fine-tune and reset the crucible body (4) before cleaning the micropores, so that the crucible body (4) and the crucible lid (5) generate a small vibration, which loosens the solidified impurities.

10. A silicon carbide crystal growth furnace with a crucible shaft multi-dimensional fine-tuning mechanism according to claim 1, characterized in that, After cleaning, the bonding plate (7) moves out of the joint between the crucible body (4) and the crucible lid (5) and stays there, so that the micropore exhaust is not obstructed; the second baffle (107) remains horizontal when it moves upward, forming a negative pressure zone below it, which attracts the normally discharged dust upward.

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