Apparatus and method for synthesizing silicon carbide
By combining a dual heater structure and a heat preservation system, the problem of uneven thermal field caused by traditional heaters is solved, achieving efficient and uniform silicon carbide synthesis, meeting the needs of large-scale industrial production, and improving product quality and output.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-20
- Publication Date
- 2026-03-13
AI Technical Summary
In existing technologies, the uneven temperature gradient inside the furnace caused by the traditional single resistance heater structure results in a lower temperature in the central region and incomplete reaction, which cannot meet the needs of industrial mass production at the hundred-kilogram level and limits the stable supply of downstream large-size SiC single crystals.
The system employs a dual heater structure, including an outer ring sidewall and an inner ring sidewall, forming an annular space. Combined with an insulation structure and a gas delivery system, it achieves dual heating from both inside and outside, precisely controls the temperature, reduces heat loss and the introduction of impurities, and ensures uniform reaction.
It achieves high quality and high yield of silicon carbide powder, and can synthesize hundreds of kilograms of silicon carbide in a single batch, meeting the needs of large-scale industrial production and improving raw material utilization and product purity.
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Figure CN121648819A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor material preparation technology, and in particular to apparatus and methods for synthesizing silicon carbide. Background Technology
[0002] With the continuous development of the semiconductor industry, the demand for semiconductor raw materials is also increasing. Silicon carbide (SiC) has good performance, so there is a high demand for silicon carbide powder.
[0003] High-temperature synthesis can produce silicon carbide. Specifically, a resistance heater is used to heat the raw materials in the reactor. Under suitable ambient temperature, the raw materials can react to form silicon carbide. However, the weight of SiC synthesized in a single batch is usually in the range of tens of kilograms, which cannot meet the needs of industrial-scale mass production at the hundred-kilogram level, thus limiting the stable supply of large-size SiC single crystals downstream.
[0004] Simply increasing the size of the reactor can lead to problems such as incomplete reaction of reactants and uneven crystallization of reactants, which in turn reduces the overall yield and quality of the powder. Summary of the Invention
[0005] Therefore, it is necessary to provide an apparatus and method for synthesizing silicon carbide to address at least one of the above-mentioned problems.
[0006] In a first aspect, this application provides an apparatus for synthesizing silicon carbide, the apparatus comprising: a crucible including an outer ring sidewall and an inner ring sidewall, the outer ring sidewall and the inner ring sidewall defining a reaction chamber; a first heater disposed outside the outer ring sidewall; and a second heater disposed inside the inner ring sidewall.
[0007] By designing an inner ring sidewall, the reaction chamber comprises an annular space, allowing the raw materials within the chamber to be heated both internally and externally. This optimizes the temperature distribution within the crucible, resulting in a low temperature difference between the central and peripheral regions, effectively solving the problems of thermal field skew and incomplete reaction. The apparatus for synthesizing silicon carbide according to the embodiments of this application can produce silicon carbide of high quality and in large quantities. The apparatus for synthesizing silicon carbide can synthesize hundreds of kilograms of silicon carbide in a single batch.
[0008] In some embodiments, the outer ring sidewall and the inner ring sidewall have a concentric circle shape.
[0009] With this setup, the crucible's annular space has a uniform width and the heat field is evenly distributed; the reaction temperature is easy to control, effectively avoiding overcooling in the center or overheating in the periphery; and the silicon carbide powder has good quality.
[0010] In some embodiments, the crucible further includes a bottom wall, a top, and a lid. The bottom wall is connected to the inner ring side wall and the outer ring side wall, the outer ring side wall is higher than the inner ring side wall, the top is connected to the inner ring side wall, and the lid is disposed on the outer ring side wall.
[0011] This setup effectively utilizes space and increases silicon carbide production.
[0012] In some embodiments, the apparatus for synthesizing silicon carbide further includes: a heat-insulating structure comprising a bottom heat-insulating layer disposed on the underside of the crucible, a first side heat-insulating layer disposed on the outside of the first heater, a second side heat-insulating layer disposed on the outside of the first side heat-insulating layer, and a top heat-insulating layer disposed on the upper side of the crucible; the first side heat-insulating layer comprises a rigid felt, and the second side heat-insulating layer comprises a soft felt.
[0013] This setup helps reduce heat loss and ensures heating effectiveness.
[0014] In some embodiments, the apparatus for synthesizing silicon carbide further includes: a gas delivery system connected to the reaction chamber; and a controller electrically connected to the first heater, the second heater, and the gas delivery system, the controller being capable of controlling the heating temperature of the first heater and the heating temperature of the second heater, respectively.
[0015] This setup reduces the introduction of impurities and oxides, ensuring the purity of silicon carbide; it also allows for precise and effective temperature control, guaranteeing crystallization quality.
[0016] Secondly, this application provides a method for synthesizing silicon carbide, utilizing the aforementioned apparatus for synthesizing silicon carbide, the method comprising: loading raw materials into a reaction chamber; and heating the raw materials using a first heater and a second heater to obtain silicon carbide.
[0017] The aforementioned apparatus can be used to prepare silicon carbide of high quality and in large quantities.
[0018] In some embodiments, the raw materials are ball-milled and mixed before being loaded; the raw materials include silicon powder and carbon powder; after obtaining silicon carbide, the materials are cooled, ball-milled, magnetically separated, and sieved to obtain silicon carbide powder.
[0019] With this setup, the raw materials can react fully, resulting in a larger quantity and better performance of silicon carbide powder.
[0020] In some embodiments, the method further includes: evacuating to a vacuum level of 1×10⁻⁶. -3 Below Pa; argon gas is introduced to maintain the reaction atmosphere pressure in the range of 0.05 MPa to 0.1 MPa.
[0021] This setup allows the use of an argon atmosphere to ensure the purity of the powder.
[0022] In some embodiments, the heating step includes: a reaction temperature range of 2200°C to 2400°C, and holding the reaction at that temperature for 15 to 30 hours.
[0023] This setup ensures crystallization quality and yields the desired crystal form.
[0024] In some embodiments, the heating step includes raising the temperature to the reaction temperature range at a rate of 5°C / min.
[0025] This setup effectively controls the thermal field distribution, dynamically and stably achieving the reaction temperature range. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of an apparatus for synthesizing silicon carbide according to one or more embodiments;
[0027] Figure 2 This is a schematic relational block diagram of an apparatus for synthesizing silicon carbide according to one or more embodiments;
[0028] Figure 3 A schematic thermal field distribution diagram of an apparatus for synthesizing silicon carbide according to one or more embodiments;
[0029] Figure 4 This is a schematic flowchart of a method for synthesizing silicon carbide according to one or more embodiments.
[0030] Explanation of reference numerals in the attached drawings: 1. Crucible; 101. Reaction chamber; 11. Outer ring sidewall; 12. Inner ring sidewall; 13. Bottom wall; 14. Top; 15. Lid; 2. Insulation structure; 21. Bottom insulation layer; 22. First side insulation layer; 23. Second side insulation layer; 24. Top insulation layer; 1000. Apparatus for synthesizing silicon carbide; 1100. First heater; 1200. Second heater; 1300. Gas delivery system; 1400. Controller; 1500. Sensor. Detailed Implementation
[0031] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0032] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0033] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0034] Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. For example, a first heater may also be referred to as a second heater, and a second heater may also be referred to as a first heater. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0035] In this application, unless otherwise expressly specified and limited, the terms "connected," "linked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a flexible connection or a rigid connection along at least one direction; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium, or a direct connection with an intermediate medium present; and they can also refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. The terms "installed," "set," "fixed," etc., can be broadly understood as connection. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.
[0036] While researching silicon carbide synthesis methods, the inventors discovered that traditional single-resistance heater structures often employ a single-layer annular heating element, leading to significant radial and axial temperature gradients within the furnace, particularly pronounced in large-capacity furnaces. The central region experiences lower temperatures, resulting in incomplete powder sintering and reaction, causing incomplete sintering in the center and uneven crystallization of the reaction products, thus reducing the overall yield and quality of the powder. Furthermore, traditional equipment has a relatively small reactor volume, typically producing only tens of kilograms of SiC powder per synthesis, which cannot meet the demands of large-scale industrial production at the hundred-kilogram level, thus limiting the stable supply of large-size SiC single crystals downstream.
[0037] refer to Figure 1 , Figure 1 An apparatus for synthesizing silicon carbide according to an embodiment of this application is shown. This apparatus is suitable for synthesizing silicon carbide via a carbothermal reduction reaction. For ease of description, a spatial rectangular coordinate system XYZ is established, with the Z-axis direction parallel to the vertical.
[0038] In an exemplary embodiment, the apparatus 1000 for synthesizing silicon carbide includes a crucible 1, a first heater 1100, and a second heater 1200. The first heater 1100 and the second heater 1200 can be independently controlled for heating.
[0039] The crucible 1 includes an outer ring sidewall 11 and an inner ring sidewall 12. The crucible 1 has a reaction chamber 101, with at least a portion of the reaction chamber 101 defined between the outer ring sidewall 11 and the inner ring sidewall 12. At least a portion of the reaction chamber 101 is an annular space between the outer ring sidewall 11 and the inner ring sidewall 12. Conventional cylindrical spaces tend to have large diameters, making it difficult to address the large temperature difference between the inner and outer rings when heating the outer ring. The inner ring sidewall 12 allows the reaction chamber 101 to include an annular space; although the outer diameter may increase to improve yield, the annular width is controllable.
[0040] The first heater 1100 is located on the outer side of the outer ring sidewall 11. The second heater 1200 is located on the inner side of the inner ring sidewall 12. The two heaters work together to form a stable and uniform annular thermal field, which helps to avoid overheating at the periphery or undercooling at the center, which can lead to abnormal product performance at the periphery or incomplete reaction at the center. The raw materials in the reaction chamber 101 of the crucible 1 can be heated from both inside and outside, and the thermal field in the reaction chamber 101 is uniformly distributed, ensuring complete reaction of the raw materials.
[0041] The apparatus 1000 for synthesizing silicon carbide according to the embodiments of this application can produce silicon carbide of good quality and in large quantity, thereby improving raw material utilization and reducing production costs. The apparatus 1000 for synthesizing silicon carbide can synthesize hundreds of kilograms of silicon carbide in a single batch, meeting the needs of large-scale industrial production and promoting the large-scale development of the semiconductor SiC industry chain.
[0042] The outer ring sidewall 11 and the inner ring sidewall 12 can be concentric circles. The width of the annular space in the crucible 1 is uniform throughout, effectively controlling the reaction temperature and ensuring a uniform thermal distribution. The reaction conditions for silicon carbide powder of the same batch are similar, resulting in stable quality.
[0043] The crucible 1 also includes a bottom wall 13 and a top cap 14. The bottom wall 13 can be located at the bottom along the Z-axis. The bottom wall 13 is connected to the inner ring side wall 12 and the outer ring side wall 11, and can support the powder. The top cap 14 can be located above the inner ring side wall 12 along the Z-axis, and the top cap 14 is connected to the inner ring side wall 12.
[0044] The outer ring sidewall 11, inner ring sidewall 12, bottom wall 13, and top cap 14 can constitute the pot body. The crucible 1 may also include a lid 15, which can be movably or detachably connected to the pot body. The lid 15 can be placed on the outer ring sidewall 11.
[0045] refer to Figure 1 The outer ring sidewall 11 is higher than the inner ring sidewall 12, and the lid 15 is disposed on the outer ring sidewall 11 and spaced apart from the cap 14. Not only do the outer ring sidewall 11 and inner ring sidewall 12 define the reaction chamber 101, but the cap 14 and lid 15 also define the reaction chamber 101. The space above the cap 14 can also be used for silicon carbide synthesis. The space of the crucible 1 is effectively utilized, increasing the yield of silicon carbide.
[0046] The first heater 1100 can project along the X-axis to cover the entire outer ring sidewall 11, or it can cover the entire reaction chamber 101. For example, the first heater 1100 is used to heat a sufficiently high stockpile of raw materials to a sufficient temperature. The second heater 1200 can correspond to the entire inner ring sidewall 12, or it can have a certain installation gap with the cap 14.
[0047] The first heater 1100 can be a resistance heater, arranged in a ring around the outer ring sidewall 11. The second heater 1200 can be a resistance heater, which can be arranged in a coaxial ring structure with the first heater 1100 and can be coaxial with the crucible 1. The second heater 1200 surrounds the inner sidewall 12.
[0048] The height of the inner ring sidewall 12 can be greater than the distance between the top 14 and the lid 15, which helps to ensure that the second heater 1200 can effectively heat the central area of the crucible 1 as a whole. The raw materials on the top 14 can also be within the effective control range of the thermal field, ensuring that the raw materials in the reaction chamber 101 are reliably heated, which helps to ensure the yield, purity and performance of silicon carbide.
[0049] The apparatus 1000 for synthesizing silicon carbide may also include a heat insulation structure 2. The heat insulation structure 2 can enclose the crucible 1 and the two heaters, which helps to reduce heat loss, maintain the temperature inside the crucible 1, and ensure the heating effect on the raw materials for the synthesis of silicon carbide.
[0050] Exemplarily, the insulation structure 2 may include a bottom insulation layer 21, a side insulation layer, and a top insulation layer 24. The bottom insulation layer 21 is disposed on the lower side of the crucible 1, providing bottom insulation to prevent heat loss and helping to maintain thermal uniformity. The side insulation layer surrounds the crucible 1, specifically surrounding the first heater 1100. The side insulation layer facilitates radial insulation, enabling the apparatus 1000 for synthesizing silicon carbide to efficiently utilize the heating capacity of the heater, reduce production consumption, and ensure the heating temperature of the raw materials. The top insulation layer 24 is disposed on the upper side of the crucible 1 to reduce top heat loss and enhance thermal field sealing.
[0051] The insulation structure 2 may include multiple side insulation layers, such as a first side insulation layer 22 disposed outside the first heater 1100 and a second side insulation layer 23 disposed outside the first side insulation layer 22. The multi-layer structure enhances radial insulation. The first side insulation layer 22 may include rigid felt, and the second side insulation layer 23 may include soft felt, which helps reduce heat loss and ensures heating efficiency. The material of the crucible 1 may include graphite, which can withstand high temperatures, ensures silicon carbide synthesis, and helps avoid introducing impurities.
[0052] refer to Figure 1 The side insulation layer can be disposed on the bottom insulation layer 21. The bottom insulation layer 21 can have a stepped structure, with the annular side insulation layer nested at the stepped structure, ensuring a firm connection and improving the airtightness of the internal space. For example, a first side insulation layer 22 can be connected to the bottom insulation layer 21, and a second side insulation layer 23 can be attached to the outer periphery of the first side insulation layer 22. The top insulation layer 24 can be disposed on the side insulation layer, or in other arrangements. The top insulation layer 24 can be detachably installed on the side insulation layer for easy loading of raw materials and removal of products.
[0053] Combination Figure 2 As shown, in some embodiments, the apparatus 1000 for synthesizing silicon carbide further includes a gas delivery system 1300. The gas delivery system 1300 is connected to the reaction chamber 101. The gas delivery system 1300 can be disposed outside the insulation structure 2 and can be connected to the reaction chamber 101 through the top insulation layer 24. Furthermore, the gas delivery system 1300 can be connected to the lid 15 or the outer ring sidewall 11. The gas delivery system 1300 can both draw in and deliver gas, reducing the introduction of impurities and oxides, ensuring the purity and crystal quality of silicon carbide, and thus meeting the stringent material quality requirements of high-end semiconductor devices. The crucible 1 or the insulation structure 2 can achieve a sealed environment.
[0054] The apparatus 1000 for synthesizing silicon carbide may further include a controller 1400, which is electrically connected to the first heater 1100, the second heater 1200, and the gas delivery system 1300. The controller 1400 can control the heating and cooling of the heaters according to a program, and can also control the operation of the gas delivery system 1300. The controller 1400 can control the heating temperature of the first heater 1100 and the second heater 1200 respectively, enabling precise and effective temperature regulation to ensure crystallization quality.
[0055] The apparatus 1000 for synthesizing silicon carbide may further include a sensor 1500, which may include a temperature sensor and a pressure sensor. The pressure sensor is used to sense pressure, for example, to obtain the pressure within the reaction chamber 101. The temperature sensor is used to sense temperature, for example, to obtain the temperature within the reaction chamber 101.
[0056] The controller 1400 is connected to the sensor 1500 and can control the system based on the sensor signal. For example, it can control the gas delivery system 1300 based on the air pressure signal, or control the first heater 1100 and the second heater 1200 based on the temperature signal.
[0057] The apparatus 1000 for synthesizing silicon carbide provided in this application, through the coordinated operation of functional units such as a double-ring resistance heater, a heat-insulating structure 2, a large-capacity graphite crucible 1, a precision gas delivery system 1300, and sensors 1500 for real-time process monitoring, achieves uniform control of the thermal field, high purity control of the product, and large-scale reaction integration. By integrating real-time temperature, pressure, and atmospheric composition monitoring, combined with automated control, the synthesis process is dynamically optimized, ensuring batch-to-batch product consistency and high yield.
[0058] refer to Figure 3 , Figure 3 The temperature distribution of the reaction chamber 101 under heating conditions according to an embodiment of this application is shown in a finite element simulation. By adjusting the power ratio of the first heater 1100 and the second heater 1200, optimized control of the temperature distribution in the powder reaction zone can be achieved, significantly reducing the temperature difference between the center and the edge. The high temperature can reach 2316 degrees Celsius (°C), and the low temperature is also around 2295 degrees Celsius. When the apparatus 1000 for synthesizing silicon carbide in this embodiment of the application is working, the temperature difference of the reaction chamber 101 is controlled within ±30°C, solving the problems of thermal field skew and incomplete reaction that exist in traditional furnaces.
[0059] refer to Figure 4This application provides a method 2000 for synthesizing silicon carbide, which can be performed using the aforementioned apparatus 1000 for synthesizing silicon carbide. The method 2000 for synthesizing silicon carbide may include steps S210 and S220.
[0060] For example, the method 2000 for synthesizing silicon carbide may further include a step S230 for preparing materials, which involves ball milling and mixing the raw materials. The raw materials include silicon powder and carbon powder.
[0061] In step S210, raw materials are loaded into the reaction chamber 101. Additionally, the crucible 1, the insulation structure 2, etc., can be assembled.
[0062] Exemplarily, the method 2000 for synthesizing silicon carbide may further include steps S240 and S250. Step S240 involves evacuating a vacuum, which facilitates the removal of gas from the reaction chamber 101. Step S250 involves introducing argon gas, which can be used to ensure the purity of the powder. Other suitable inert gases may also be introduced to provide an atmosphere for the reaction.
[0063] Step S220: Heating the raw materials to obtain silicon carbide. Specifically, the raw materials can be heated using a first heater 1100 and a second heater 1200 to obtain silicon carbide. The apparatus 1000 used for synthesizing silicon carbide achieves a good thermal field, allowing the raw materials to react fully and resulting in the production of high-quality, high-volume silicon carbide.
[0064] After obtaining silicon carbide, it can be cooled, ball-milled, magnetically separated, and sieved to obtain silicon carbide powder with a large quantity and good performance.
[0065] For example, in method 2000 for synthesizing silicon carbide, high-purity silicon powder and high-purity carbon powder are weighed in a molar ratio of 1:1, wherein the purity of the high-purity silicon powder can reach 99.999% and the purity of the high-purity carbon powder can reach 99.9995%. A homogeneous mixture is obtained by thorough ball milling, for example, for 12 hours.
[0066] The mixture is placed into a crucible 1 made of high-purity graphite material, and the lid 15 is placed on top. The crucible 1 is then placed in the annular space formed by the first heater 1100 and the second heater 1200.
[0067] Vacuuming is 1×10 -3 Below Pa. High-purity argon gas is introduced, with a purity greater than or equal to 99.999%. The reaction atmosphere is pressurized and maintained. The reaction atmosphere can be maintained at atmospheric pressure or slightly higher. The reaction atmosphere pressure range can be from 0.05 MPa to 0.1 MPa.
[0068] During the heating step, the temperature can be increased at a rate of 5℃ / min to a reaction temperature range of 2200℃ to 2400℃, and the reaction can be maintained at this temperature for 15h to 30h. The reaction formula is: Si(s) + C(s) → SiC(s).
[0069] After the reaction, the product can be naturally cooled to room temperature. Once cooled sufficiently, the reaction product is removed from crucible 1 and subjected to post-processing steps such as ball milling, magnetic separation, and sieving to prepare the required silicon carbide powder.
[0070] The technical features of the above-disclosed embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0071] In the embodiments disclosed above, unless otherwise explicitly specified and limited, the execution order of each step is not restricted. For example, they can be executed in parallel or sequentially in different orders. The sub-steps of each step can also be executed alternately. Various forms of processes described above can be used, and steps can be reordered, added, or deleted, as long as the desired result of the technical solution provided in this application can be achieved, and this application does not impose any restrictions here.
[0072] The embodiments disclosed above merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of patent protection claimed by this application. Therefore, the scope of patent protection of this application should be determined by the appended claims.
Claims
1. An apparatus for synthesizing silicon carbide, characterized in that, include: A crucible, the crucible including an outer ring sidewall and an inner ring sidewall, the outer ring sidewall and the inner ring sidewall being used to define a reaction chamber; A first heater is disposed on the outer side of the outer ring sidewall; and The second heater is located on the inner side of the inner ring sidewall.
2. The apparatus for synthesizing silicon carbide according to claim 1, characterized in that, The outer ring sidewall and the inner ring sidewall have a concentric circle shape.
3. The apparatus for synthesizing silicon carbide according to claim 1, characterized in that, The crucible also includes a bottom wall, a top, and a lid. The bottom wall is connected to the inner ring side wall and the outer ring side wall. The outer ring side wall is higher than the inner ring side wall. The top is connected to the inner ring side wall. The lid is disposed on the outer ring side wall.
4. The apparatus for synthesizing silicon carbide according to claim 1, characterized in that, Also includes: The insulation structure includes a bottom insulation layer disposed on the lower side of the crucible, a first side insulation layer disposed on the outside of the first heater, a second side insulation layer disposed on the outside of the first side insulation layer, and a top insulation layer disposed on the upper side of the crucible; the first side insulation layer includes a hard felt, and the second side insulation layer includes a soft felt.
5. The apparatus for synthesizing silicon carbide according to claim 1, characterized in that, Also includes: A gas delivery system is connected to the reaction chamber; The controller is electrically connected to the first heater, the second heater, and the gas delivery system. The controller is capable of controlling the heating temperature of the first heater and the heating temperature of the second heater, respectively.
6. A method for synthesizing silicon carbide, characterized in that, The method, using the apparatus for synthesizing silicon carbide as described in any one of claims 1 to 5, comprises: The raw materials are loaded into the reaction chamber; and The raw material is heated using the first heater and the second heater to obtain silicon carbide.
7. The method for synthesizing silicon carbide according to claim 6, characterized in that, Before loading the raw materials, the raw materials are ball-milled and mixed; the raw materials include silicon powder and carbon powder; After obtaining the silicon carbide, it is subjected to cooling, ball milling, magnetic separation and sieving to obtain silicon carbide powder.
8. The method for synthesizing silicon carbide according to claim 6, characterized in that, The method further includes: vacuuming at a rate of 1×10⁻⁶. -3 Below Pa; argon gas is introduced to maintain the reaction atmosphere pressure in the range of 0.05 MPa to 0.1 MPa.
9. The method for synthesizing silicon carbide according to any one of claims 6 to 8, characterized in that, The heating step includes: a reaction temperature range of 2200℃ to 2400℃, and a holding temperature reaction for 15h to 30h.
10. The method for synthesizing silicon carbide according to claim 9, characterized in that, The heating step includes: heating to the reaction temperature range at a heating rate of 5°C / min.