A composite electrode for a single crystal furnace

Abstract

The utility model discloses a kind of composite electrode for single crystal furnace, comprising: first electrode body, second electrode body and third electrode body;The first electrode body, the second electrode body and the third electrode body are hollow cylindrical structure;The first electrode body is connected with the second electrode body by screw thread, the second electrode body is connected with the third electrode body by screw thread close to the second electrode body;The first electrode body, the second electrode body and the third electrode body constitute the hollow cavity of conductive body with;The inside of the hollow cavity is filled with heat-insulating material at least partially.The utility model provides stable passage for current conduction.Effectively reduce contact resistance, ensure that in single crystal furnace working process, electric energy can be transmitted efficiently and stably.Avoid the problem of poor contact, the existence of heat-insulating material breaks the radial heat conduction of composite electrode for single crystal furnace, greatly reduce the loss of heat in radial direction.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor manufacturing technology, and in particular to a composite electrode for a single crystal furnace. Background Technology

[0002] In the production process of single crystal furnaces, electrodes, as key components, play a crucial role in conducting electricity and generating heat, and providing the necessary temperature environment for crystal growth. Their performance directly affects the quality and efficiency of single crystal growth. With the continuous improvement of the requirements for the quality and production efficiency of single crystal silicon in industries such as semiconductors and photovoltaics, higher standards have been set for the performance of electrodes used in single crystal furnaces.

[0003] Traditional single-crystal furnace electrodes often employ an integral or simply assembled structure, requiring complete replacement of any damaged component, resulting in high maintenance costs. Furthermore, the connections between components are not robust enough, leading to poor contact under prolonged high-temperature, high-current operation, causing increased resistance and energy consumption. Simultaneously, traditional electrodes generally lack effective heat insulation, allowing significant heat loss through radial conduction, thus wasting energy. Utility Model Content

[0004] To address the aforementioned technical problems, the specific technical solution of this utility model is as follows:

[0005] A composite electrode for a single crystal furnace includes: a first electrode body, a second electrode body, and a third electrode body; the first electrode body, the second electrode body, and the third electrode body are hollow cylindrical structures;

[0006] The second electrode body is disposed between the first electrode body and the third electrode body. The end of the first electrode body near the second electrode body is threadedly connected to the end of the second electrode body near the first electrode body. The end of the second electrode body near the third electrode body is threadedly connected to the end of the third electrode body near the second electrode body. The axial directions of the first electrode body, the second electrode body and the third electrode body overlap.

[0007] The first electrode, the second electrode, and the third electrode constitute a conductor with a hollow cavity.

[0008] The hollow cavity is at least partially filled with insulation material, which is used to block radial heat conduction of the composite electrode for the single crystal furnace.

[0009] Furthermore, the outer surface of the first electrode body near the end of the second electrode body is provided with a first external thread structure; the second electrode body near the end of the first electrode body is provided with a first internal thread hole adapted to the first external thread structure, and the end of the second electrode body away from the first electrode body is provided with a second internal thread hole; the outer surface of the third electrode body near the end of the second electrode body is provided with a second external thread structure adapted to the second internal thread hole.

[0010] Furthermore, the threaded connection interfaces between the first electrode body and the second electrode body, and between the second electrode body and the third electrode body, are coated with a conductive graphite paste layer.

[0011] Furthermore, a graphite gasket is provided at the threaded connection interface between the first electrode body and the second electrode body, and between the second electrode body and the third electrode body.

[0012] Furthermore, the hollow cavity includes a first connecting section, a filling section, and a second connecting section, with the filling section filled with the thermal insulation material.

[0013] Furthermore, the first connecting section includes a third internal threaded hole provided on one end of the first electrode body away from the second electrode body. The third internal threaded hole is used to connect with the single crystal furnace heater. The single crystal furnace heater is provided with an external thread structure that mates with the third internal thread.

[0014] Furthermore, the second connecting section includes a fourth internal threaded hole provided on one end of the third electrode body away from the second external threaded structure. The fourth internal threaded hole is used to connect with the single crystal furnace electrode, and the single crystal furnace electrode is provided with an external threaded structure that mates with the fourth internal thread.

[0015] Furthermore, a first annular boss is provided on the top surface of the first electrode body, and a plurality of bolt mounting holes are provided at intervals on the first annular boss. The bolt mounting holes are used for bolt connection with the single crystal furnace heater.

[0016] The diameter of the first annular boss is larger than the diameter of the first electrode body.

[0017] Furthermore, a second annular boss is provided at the end of the third electrode body opposite to the second electrode body, and the second annular boss is used to increase the flow area of ​​the third electrode body;

[0018] The diameter of the second annular boss is larger than the diameter of the third electrode.

[0019] Furthermore, the outer surfaces of the first electrode, the second electrode, and the third electrode are coated with an antioxidant coating.

[0020] This utility model also provides a graphite single crystal furnace, which includes the above-mentioned composite electrode for single crystal furnace, single crystal furnace heater, single crystal furnace electrode and single crystal furnace body.

[0021] This invention utilizes a first electrode, a second electrode, and a third electrode connected by threads to form a conductive body, providing a stable path for current conduction. The threaded connection ensures tight contact between the electrodes, effectively reducing contact resistance and guaranteeing that the axial current of the composite electrode can be smoothly transferred from the third electrode to the second electrode and then to the first electrode, ensuring efficient and stable power transmission during the operation of the single crystal furnace. This avoids poor contact problems, as well as increased resistance, increased energy consumption, and localized overheating, further preventing impacts on electrode lifespan and the stability of single crystal growth. The first, second, and third electrode bodies constitute a conductive body with a hollow cavity; the interior of the hollow cavity is at least partially filled with insulation material. The presence of the insulation material blocks radial heat conduction of the composite electrode in the single crystal furnace, greatly reducing heat loss in the radial direction. This allows the heat conducted by the electrodes to be more concentrated on the growth region of the single crystal silicon, improving energy utilization and reducing energy consumption. Attached Figure Description

[0022] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0023] Figure 1 This is a schematic diagram of the structure of a composite electrode for a single crystal furnace according to a specific embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of the first electrode body in a specific embodiment of the present invention.

[0025] Figure 3 This is a top view of the first electrode body in a specific embodiment of the present invention.

[0026] Figure 4 This is a top view of the second electrode body in a specific embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of the structure of the third electrode in a specific embodiment of the present invention.

[0028] Reference numerals: 10: First electrode body; 20: Second electrode body; 30: Third electrode body; 40: Hollow cavity; 11: First external thread structure; 12: First annular boss; 21: First internal thread hole; 22: Second internal thread hole; 31: Second external thread structure; 32: Second annular boss; 33: Third internal thread hole; 41: Thermal insulation material; Detailed Implementation

[0029] The present invention will now be described in detail with reference to the described embodiments. While specific embodiments of the present invention have been shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0030] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments of the present invention; however, these descriptions are intended to illustrate the general principles of the specification and are not intended to limit the scope of the present invention. The scope of protection of this invention shall be determined by the appended claims.

[0031] refer to Figure 1 As shown, this invention discloses a composite electrode for a single-crystal furnace, comprising: a first electrode body 10, a second electrode body 20, and a third electrode body 20; the first electrode body 10, the second electrode body 20, and the third electrode body 20 are hollow cylindrical structures; the second electrode body 20 is disposed between the first electrode body 10 and the third electrode body 20, with the end of the first electrode body 10 near the second electrode body 20 threadedly connected to the end of the second electrode body 20 near the first electrode body 10, and the end of the second electrode body 20 near the third electrode body 20 threadedly connected to the end of the third electrode body 20 near the second electrode body 20; the axial directions of the first electrode body 10, the second electrode body 20, and the third electrode body 20 overlap; the first electrode body 10, the second electrode body 20, and the third electrode body 20 constitute a conductor having a hollow cavity 40; the interior of the hollow cavity 40 is at least partially filled with a thermal insulation material 41, which is used to block radial heat conduction of the composite electrode for the single-crystal furnace.

[0032] Specifically, the composite electrode consists of a first electrode body 10, a second electrode body 20, and a third electrode body 20, disposed between the first electrode body 10 and the third electrode body 20 via the second electrode body 20. The end of the first electrode body 10 closest to the second electrode body 20 is threadedly connected to the end of the second electrode body 20 closest to the first electrode body 10. The end of the second electrode body 20 closest to the third electrode body 20 is threadedly connected to the section of the third electrode body 20 closest to the second electrode body 20. The axial directions of the first electrode body 10, the second electrode body 20, and the third electrode body 20 overlap, forming a highly efficient and stable conductor. Current is transmitted from the third electrode body 20 through the second electrode body 20 to the first electrode body 10, achieving seamless axial current conduction and ensuring uniform current distribution and utilization within the composite electrode. The cylindrical structure of the first electrode body 10, the second electrode body 20, and the third electrode body 20 provides a uniform conduction path for the current, reducing current loss and interference during transmission. The cylindrical structure of the first electrode body 10, the second electrode body 20, and the third electrode body 20 enhances the structural stability of the composite electrode. When the composite electrode is subjected to external forces such as high temperature, gravity, and possible vibration in the single crystal furnace, the cylindrical structure effectively disperses stress and prevents loosening of the connection between the electrode bodies. The threaded connection ensures tight contact between the electrode bodies, effectively reducing contact resistance and ensuring that the axial current of the composite electrode can be smoothly transmitted from the third electrode body 20 through the second electrode body 20 to the first electrode body 10. This ensures efficient and stable power transmission during the operation of the single crystal furnace, avoiding poor contact problems, increased resistance, increased energy consumption, and local overheating, further preventing impact on the electrode's service life and the stability of single crystal growth. Furthermore, with the composite electrode composed of three electrode bodies, if any sub-component is damaged, only the corresponding electrode body needs to be replaced, without replacing the entire electrode, greatly reducing maintenance and time costs.

[0033] Furthermore, when the single-crystal furnace is running, the core temperature of the electrode can reach over 1600℃. The hollow cavity 40 along the axial direction of the composite electrode is filled with insulating material 41, whose low thermal conductivity effectively blocks radial heat loss from the electrode. This allows the heat generated by the electrode to be more concentrated on the growth region of the single-crystal silicon, preventing heat from escaping to the external environment of the furnace and thus reducing the overall power consumption of the single-crystal furnace. Simultaneously, a stable thermal field distribution helps to precisely control the temperature during the single-crystal silicon growth process, avoiding crystal defects caused by uneven heat conduction and improving the quality of the single-crystal silicon.

[0034] Furthermore, the first electrode body 10, the second electrode body 20, and the third electrode body 20 can be low-power electrode materials such as isostatically pressed high-purity graphite and modified graphite composite materials. The low resistivity of isostatically pressed high-purity graphite ensures uniform current conduction and possesses thermal stability, maintaining stable performance at high temperatures, ensuring smooth current conduction within the electrode, and effectively resisting deformation or damage caused by thermal stress. Modified graphite composite materials are based on high-purity graphite, modified through physical or chemical methods to improve its conductivity, thermal stability, and mechanical strength. These modified graphite composite materials not only retain the original conductivity of graphite but also enhance its high-temperature resistance, corrosion resistance, and oxidation resistance through modification, enabling the first electrode body 10, the second electrode body 20, and the third electrode body 20 to maintain stable performance at high temperatures, ensuring smooth current conduction within the composite electrode.

[0035] Furthermore, the insulation material 41 can be rock wool, glass wool, aluminum silicate fiber, etc. Rock wool uses natural rock as its main raw material, which is melted at high temperatures and then centrifuged to form a fibrous material. It has excellent fire resistance, is a non-combustible material, and does not produce toxic gases at high temperatures. Its low thermal conductivity effectively prevents heat transfer and also provides good sound absorption and noise reduction. Glass wool is made by fiberizing molten glass to form a cotton-like material. It has low thermal conductivity, provides thermal insulation, and also possesses elasticity and shock absorption properties, absorbing a certain amount of vibration energy. It has good chemical stability and is not easily corroded. Aluminum silicate fiber is made from aluminum silicate through melt blowing or spun fibers. It has high-temperature resistance, can be used for a long time in high-temperature environments without deformation or pulverization, has low thermal conductivity, and exhibits good chemical stability and thermal shock resistance.

[0036] In one specific implementation, refer to Figure 2 and Figure 3 The outer surface of the first electrode body 10, near the end of the second electrode body 20, is provided with a first external thread structure 11; Reference Figure 4 As shown, the second electrode body 20 has a first internal threaded hole 21 at one end near the first electrode body 10, which is adapted to the first external thread structure 11; the second electrode body 20 has a first internal threaded hole 22 at one end away from the first electrode body 10; Reference Figure 5As shown, the outer surface of the third electrode body 20 facing the second electrode body 20 has a second external thread structure 32 that matches the first internal thread hole 22. The first external thread structure 11 at the bottom of the first electrode body 10 matches the first internal thread hole 21 at the end of the second electrode body 20 facing the first electrode body 10. This threaded connection not only achieves a mechanical connection between the two electrode bodies, but more importantly, ensures a good electrical connection. Simultaneously, the two ends of the second electrode body 20 are respectively provided with internal thread holes that match the first electrode body 10 and the third electrode body 20. The three electrode bodies are tightly connected together through the threaded connection, further improving the reliability of the connection. The stable connection structure ensures that the composite electrode can maintain good performance under complex working environments, extending the electrode's service life. The second external thread structure 32 on the third electrode body 20 mates with the first internal thread hole 22 at the end of the second electrode body 20 facing away from the first electrode body 10. During the operation of the single crystal furnace, current is transmitted from the third electrode 20 through the second electrode 20 to the first electrode 10. The tightly fitted threaded connection ensures a large and stable contact area between the electrodes, effectively reducing contact resistance. This allows the current to pass through the composite electrode stably and efficiently, providing stable electrical energy for single crystal silicon growth and preventing current fluctuations from affecting the growth quality and efficiency of the single crystal silicon. Furthermore, during the installation, commissioning, or maintenance of the single crystal furnace, operators can connect and disassemble the electrodes by rotating them, improving work efficiency. Moreover, when a part of the composite electrode is damaged, only the corresponding electrode needs to be disassembled and replaced, without replacing the entire electrode, reducing maintenance costs and downtime, and improving the production efficiency of the single crystal furnace.

[0037] In one specific embodiment, the threaded connection interfaces between the first electrode body 10 and the second electrode body 20, and between the second electrode body 20 and the third electrode body 20, are coated with a layer of conductive graphite paste. In a single-crystal furnace environment with high current transmission, contact resistance between electrodes can lead to energy loss and localized heating, affecting electrode efficiency and stability. Conductive graphite paste has good conductivity; when applied to the threaded connection interfaces, it can fill the microscopic unevenness and gaps between the electrode threads. These tiny gaps, without the graphite paste coating, would form a large contact resistance, hindering the smooth flow of current. The conductive graphite paste, with its own layer conductivity, allows current to be conducted more uniformly and efficiently between the electrode bodies. This not only reduces energy loss due to contact resistance and lowers the overall power consumption of the composite electrode, but also avoids localized overheating, ensuring a stable power supply required for single-crystal silicon growth. The conductive graphite paste also has adhesiveness and lubricity. Adhesiveness can enhance the tightness of the connection between the electrodes. During the operation of the single crystal furnace, when the electrodes are affected by external forces such as vibration and thermal expansion and contraction, it can effectively prevent the threaded connection between the electrodes from loosening. Lubricity plays a role in the installation and disassembly of the electrodes, reducing the friction between the threads, improving the convenience and efficiency of operation, and reducing the damage to the threads caused by excessive force during installation or disassembly, thus extending the service life of the composite electrode.

[0038] In one specific embodiment, a graphite gasket is provided at the threaded connection interface between the first electrode body 10 and the second electrode body 20, and between the second electrode body 20 and the third electrode body 20. The graphite gasket is embedded in the first internal threaded hole 21 and the first internal threaded hole 22 of the second electrode body 20. The graphite gasket has excellent high temperature resistance and low thermal conductivity. When embedded in the first internal threaded hole 21 and the first internal threaded hole 22 of the second electrode body 20, a continuous sealing layer can be formed at the electrode body connection interface, effectively preventing the insulation material 41 inside the hollow cavity 40 from contacting the external environment. This further reduces radial heat conduction, making the heat more concentrated in the axial transmission path, which not only improves energy utilization efficiency but also avoids the thermal radiation effect of high temperature on the surrounding components of the furnace body. The graphite gasket has good electrical conductivity and is evenly distributed at the threaded interface, which can expand the current conduction area and reduce contact resistance. The current transmission between the electrodes is more uniform and stable, reducing the hot spot effect caused by excessive local resistance. During the operation of the single crystal furnace, the composite electrode is subjected to both high-temperature thermal cycling and mechanical vibration, which can easily lead to fatigue and loosening of the threaded connection. The layered structure of the graphite gasket has a good elastic modulus, which can effectively absorb the stress generated by the difference in thermal expansion and buffer the impact of mechanical vibration on the thread.

[0039] In one specific embodiment, the hollow cavity 40 includes a first connecting section, a filling section, and a second connecting section, with the filling section filled with the insulation material 41. The hollow cavity 40 is composed of a hollow structure consisting of a first electrode body 10, a second electrode body 20, and a third electrode body 20. The first connecting section is located at the end of the first electrode body facing away from the second electrode body 20, and the second connecting section is located at the end of the third electrode body 20 facing away from the second electrode body 20. The first and second connecting sections are respectively located at both ends of the hollow cavity 40, achieving a tight connection with the single-crystal graphite furnace. The filling section is located between the first and second connecting sections and is filled with the insulation material 41. The insulation material 41 has good thermal insulation performance, effectively reducing heat transfer and energy loss. The insulation material 41 has excellent thermal insulation effect and flexibility, adapting to the shape of the filling section to ensure dense filling and reduce heat loss. The shape and size of the filling section can be designed according to actual needs to ensure that the insulation material 41 is fully filled and achieves the best thermal insulation effect.

[0040] In one specific implementation, reference is made to Figure 2 and Figure 3 The first connecting segment shown includes a third internal threaded hole 33 on the end of the first electrode body 10 facing away from the second electrode body 20. The third internal threaded hole 33 is used to connect with the single crystal furnace heater. The single crystal furnace heater is provided with an external thread structure that mates with the third internal thread. When the hollow cavity 40 and the single crystal furnace heater are screwed together, a strong clamping force is generated, ensuring a tight connection between the hollow cavity 40 and the single crystal furnace heater. This not only significantly improves the stability of the connection, allowing the composite electrode to maintain excellent connection performance even under extreme working environments such as high temperature and high pressure, effectively preventing heat loss caused by loose connection; the threaded connection also optimizes the heat transfer path, reducing contact thermal resistance during heat transfer, allowing heat to be transferred more efficiently from the single crystal furnace heater to the composite electrode. The threaded connection method also greatly facilitates the maintenance and replacement of the composite electrode, making the disassembly and installation of the composite electrode and the single crystal furnace heater faster and more convenient, effectively reducing equipment maintenance costs and downtime, and providing a strong guarantee for the efficient and stable operation of photovoltaic single crystal silicon rod production.

[0041] In one specific embodiment, the second connecting section includes a fourth internal threaded hole on the end of the third electrode body 20 facing away from the second external thread structure 32. The fourth internal threaded hole is used to connect with the single crystal furnace electrode, and the single crystal furnace electrode is provided with an external thread structure that mates with the fourth internal thread. When the single crystal furnace electrode is screwed into the fourth internal threaded hole, the thread engagement generates an axial tightening force that can overcome the thermal expansion limitations of traditional cylindrical connections. In high-temperature environments, the elastic deformation of the thread compensates for the difference in thermal expansion coefficients between the single crystal furnace electrode and the composite electrode, effectively eliminating interface gaps. The thread structure allows a continuous circumferential conductive path to be formed between the composite electrode and the single crystal furnace electrode, reducing the contact resistance between the composite electrode and the single crystal furnace electrode, while also enabling quick disassembly and maintenance. The tight fit between the fourth internal threaded hole and the external thread on the single crystal furnace electrode achieves a low-contact-resistance electrical connection, significantly reducing energy loss during current transmission, improving energy utilization efficiency, and helping to reduce the operating costs of the single crystal furnace. Furthermore, a stable electrical connection can ensure stable current transmission, reduce the impact of current fluctuations on the monocrystalline silicon growth process, and improve the growth quality and yield of monocrystalline silicon.

[0042] In one specific embodiment, the ends of the first and second connecting segments opposite to the filling section are provided with an inner chamfer structure, and the ends of the first and second connecting segments near the filling section are provided with a tool relief groove. The inner chamfer structure makes the connection between the first and second connecting segments and the single crystal furnace heater and the single crystal furnace electrode smoother, reducing stress concentration and improving the overall structural strength of the composite electrode. Simultaneously, the inner chamfer structure also serves as a guide, facilitating the assembly of the hollow cavity 40 device with external components. The tool relief groove provides space for the tool to exit during thread machining, preventing interference between the tool and the connecting segment and ensuring smooth machining. Furthermore, the thread with the tool relief groove allows for a tighter connection between the first and second connecting segments and the single crystal furnace heater and the single crystal furnace electrode, avoiding assembly gaps or loosening caused by incomplete thread ends, thereby improving assembly reliability and stability and ensuring the normal operation of the composite electrode.

[0043] In one specific implementation, reference is made to Figure 2 and Figure 3The first electrode body 10 shown has a first annular boss 12 on its top surface, with multiple bolt mounting holes spaced apart. These bolt mounting holes are used for bolt connection with the single crystal furnace heater. The diameter of the first annular boss 12 is larger than the diameter of the first electrode body 10. The first annular boss 12, with its multiple bolt mounting holes, provides a positioning reference for the installation of the heater connected to the single crystal furnace, guiding the heater to be accurately aligned with the first electrode body 10 and avoiding problems such as poor contact and uneven force due to assembly deviations. Simultaneously, the detachable bolt connection makes the installation, maintenance, and repair of the equipment more convenient, reducing maintenance costs and downtime, and improving equipment availability and production efficiency. The larger diameter of the first annular boss 12 compared to the first electrode body 10 increases the connection area, improving the stability and sealing of the connection, ensuring efficient heat transfer, reducing heat loss, facilitating bolt installation and removal, and improving equipment maintainability.

[0044] In one specific implementation, reference is made to Figure 5As shown, a second annular protrusion is provided at the end of the third electrode 20 opposite to the second electrode 20. This second annular protrusion increases the current-carrying area of ​​the third electrode 20; the diameter of the second annular protrusion is larger than the diameter of the third electrode 20. When current flows in a conductor, it follows the principle of the path of least resistance, and the current density is inversely proportional to the cross-sectional area of ​​the conductor. In the electrode system, the third electrode 20 serves as an important channel for current transmission, and its current-carrying area directly affects the current transmission efficiency and resistance. When the second annular protrusion is provided at one end of the third electrode 20, the cross-sectional area of ​​the electrode at that end is significantly increased. Lower resistance means that the current encounters less resistance when passing through the third electrode 20, allowing it to flow more smoothly and thus improving the current transmission efficiency. The presence of the second annular protrusion provides a wider flow space for the current, enabling it to be more evenly distributed across the cross-section of the electrode, avoiding local current concentration, and optimizing the current conduction path. This reduces the energy consumption of the equipment and improves energy utilization efficiency. Meanwhile, the uniform current distribution reduces the occurrence of localized overheating, avoiding problems such as performance degradation, damage, or even safety accidents caused by overheating of the electrode material. This ensures the long-term stable operation of the composite electrode and extends its service life. The diameter of the second annular boss is larger than that of the third electrode 20, which significantly increases the current-carrying area of ​​the third electrode 20. By increasing the current-carrying area, the current density can be reduced, heat generation can be decreased, and thus the current transmission efficiency of the composite electrode can be improved. The second annular boss also enhances the structural strength of the third electrode 20 and improves its load-bearing capacity.

[0045] In one specific embodiment, the surfaces of the first electrode body 10, the second electrode body 20, and the third electrode body 20 are coated with an anti-oxidation coating. The anti-oxidation coating effectively prevents oxidation reactions on the surfaces of the first electrode body 10, the second electrode body 20, and the third electrode body 20, reducing the wear and tear of the composite electrode due to oxidation. During the long-term operation of the single crystal furnace, the first electrode body 10, the second electrode body 20, and the third electrode body 20 do not need frequent replacement due to oxidation corrosion, greatly extending the service life of the composite electrode. Without the anti-oxidation coating, high-temperature oxidation causes the electrode surface to gradually wear down, affecting the electrode's conductivity and mechanical strength; however, after coating with the anti-oxidation coating, the oxidation wear rate of the composite electrode is reduced, improving its service life. Oxidation reactions not only lead to the consumption of materials in the first electrode body 10, the second electrode body 20, and the third electrode body 20, but may also cause structural damage to the first electrode body 10, the second electrode body 20, and the third electrode body 20, such as the formation of cracks, holes, and other defects. The antioxidant coating maintains the integrity and density of the surfaces of the first electrode 10, the second electrode 20, and the third electrode 20 by inhibiting oxidation reactions, thus preventing structural damage caused by oxidation.

[0046] This utility model also provides a graphite single crystal furnace, including the above-mentioned composite electrode for single crystal furnace, single crystal furnace heater, single crystal furnace electrode and single crystal furnace body.

[0047] Example

[0048] A composite electrode for a single crystal furnace includes: a first electrode body 10, a second electrode body 20, and a third electrode body 20.

[0049] The first electrode body 10, the second electrode body 20, and the third electrode body 20 are hollow cylindrical structures. The outer surface of the first electrode body 10 near the end of the second electrode body 20 has a first external thread structure 11, with a length of 200 mm and a diameter of 80 mm. The first electrode body 10 is made of high-purity graphite material, possessing excellent electrical conductivity and high-temperature resistance, enabling stable operation in the high-temperature environment of a single crystal furnace. The second electrode body 20 near the end of the first electrode body 10 has a first internal thread hole 21 adapted to the first external thread structure 11, with a depth of 30 mm; the end away from the first electrode body 10 has a first internal thread hole 22, with a depth of 35 mm. The overall height of the second electrode body 20 is 150 mm. The second electrode body 20 is made of high-purity graphite material. The outer surface of the third electrode body 20 near the end of the second electrode body 20 has a second external thread structure 32, with a length of 200 mm and a diameter of 80 mm. The third electrode 20 is made of high-purity graphite material, which has excellent electrical conductivity and high temperature resistance, and can work stably in the high-temperature environment of the single crystal furnace.

[0050] Conductive graphite paste is applied to the threaded connection interfaces between the first electrode body 10 and the second electrode body 20, and between the second electrode body 20 and the third electrode body 20. The conductive graphite paste has good conductivity and lubricity, and can fill the tiny gaps between the threads, reduce contact resistance, and improve current transmission efficiency.

[0051] The hollow cavity 40 formed by the first electrode body 10, the second electrode body 20, and the third electrode body 20 has a diameter of 40 mm. The hollow cavity 40 includes a first connecting section, a filling section, and a second connecting section. The filling section is filled with glass wool insulation material 41. The first connecting section includes a third internal threaded hole 33 on the end of the first electrode body 10 facing away from the second electrode body 20. The third internal threaded hole 33 is used to connect to a single crystal furnace heater. The single crystal furnace heater has an external thread structure that mates with the third internal thread. The depth of the third internal threaded hole 33 is 30 mm. The second connecting section includes a fourth internal threaded hole on the end of the third electrode body 20 facing away from the second external thread structure 32. The fourth internal threaded hole is used to connect to a single crystal furnace electrode. The single crystal furnace electrode has an external thread structure that mates with the fourth internal thread. The depth of the fourth internal threaded hole is 30 mm. The ends of the first and second connecting sections facing away from the filling section have an internal chamfer structure with a chamfer angle of 45°. The first connecting segment and the second connecting segment are provided with a tool relief groove at one end near the filling segment, and the diameter of the tool relief groove is 70mm.

[0052] The top surface of the first electrode body 10 is provided with a first annular boss 12, which has a height of 8 mm and a width of 12 mm. The first annular boss 12 has eight bolt mounting holes spaced apart, each with a diameter of 12 mm, a depth of 15 mm, and a spacing of 35 mm between holes. The inner walls of the bolt mounting holes are tapped with M12 threads for connection to the heater of the single crystal furnace. During assembly, the heater is placed on the first annular boss 12 of the first electrode body 10, aligning the corresponding mounting holes on the heater with the bolt mounting holes on the first electrode body 10. Then, M12 bolts are inserted and tightened. The preload of the bolts secures the heater to the first electrode body 10, ensuring good electrical connection and mechanical stability. The third electrode body 20 has a second annular boss at the end opposite to the second electrode body 20. The outer diameter of the boss is 15 mm larger than the diameter of the main body of the third electrode body 20, the inner diameter is the same as the diameter of the main body of the third electrode body 20, and the height is 7 mm. The surfaces of the first electrode 10, the second electrode 20, and the third electrode 20 are all coated with an anti-oxidation coating. This anti-oxidation coating is prepared using a plasma spraying process, and the coating material is a special ceramic composite material, whose main components include alumina (60%), zirconium oxide (30%), and a small amount of rare earth oxide additives (such as yttrium oxide, 10%).

[0053] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the present utility model.

Claims

1. A composite electrode for a single crystal furnace, characterized in that, include: The first electrode, the second electrode, and the third electrode are hollow cylindrical structures. The second electrode body is disposed between the first electrode body and the third electrode body. The end of the first electrode body near the second electrode body is threadedly connected to the end of the second electrode body near the first electrode body. The end of the second electrode body near the third electrode body is threadedly connected to the end of the third electrode body near the second electrode body. The axial directions of the first electrode body, the second electrode body and the third electrode body overlap. The first electrode, the second electrode, and the third electrode constitute a conductor with a hollow cavity. The hollow cavity is at least partially filled with insulation material, which is used to block radial heat conduction of the composite electrode for the single crystal furnace.

2. The composite electrode according to claim 1, wherein The outer surface of the first electrode body near the end of the second electrode body is provided with a first external thread structure; the second electrode body near the end of the first electrode body is provided with a first internal thread hole adapted to the first external thread structure, and the end of the second electrode body away from the first electrode body is provided with a second internal thread hole; the outer surface of the third electrode body near the end of the second electrode body is provided with a second external thread structure adapted to the second internal thread hole.

3. The composite electrode of claim 2, wherein The threaded connection interfaces between the first electrode body and the second electrode body, and between the second electrode body and the third electrode body, are coated with a layer of conductive graphite paste.

4. The composite electrode of claim 2, wherein A graphite gasket is provided at the threaded connection interface between the first electrode body and the second electrode body, and between the second electrode body and the third electrode body.

5. The composite electrode of claim 1, wherein The hollow cavity includes a first connecting section, a filling section, and a second connecting section, with the filling section filled with the thermal insulation material.

6. The composite electrode of claim 5, wherein The first connecting section includes a third internal threaded hole provided on one end of the first electrode body away from the second electrode body. The third internal threaded hole is used to connect with the single crystal furnace heater. The single crystal furnace heater is provided with an external thread structure that mates with the third internal thread.

7. The composite electrode of claim 5, wherein The second connecting section includes a fourth internal threaded hole provided on one end of the third electrode body away from the second external threaded structure. The fourth internal threaded hole is used to connect with the single crystal furnace electrode. The single crystal furnace electrode is provided with an external threaded structure that mates with the fourth internal thread.

8. The composite electrode of claim 1, wherein The top surface of the first electrode body is provided with a first annular boss, and a plurality of bolt mounting holes are provided at intervals on the first annular boss. The bolt mounting holes are used for bolt connection with the single crystal furnace heater. The diameter of the first annular boss is larger than the diameter of the first electrode body.

9. The composite electrode of claim 1, wherein The third electrode body is provided with a second annular boss at the end opposite to the second electrode body, and the second annular boss is used to increase the flow area of ​​the third electrode body; The diameter of the second annular boss is larger than the diameter of the third electrode.

10. The composite electrode of claim 1, wherein The outer surfaces of the first electrode, the second electrode, and the third electrode are coated with an antioxidant coating.

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