Silicon carbide powder synthesizing device
Through the combination of the heating chamber and auxiliary heat chamber and hollow shaft agitation, the problem of insufficient synthesis of silicon carbide powder caused by uneven temperature is solved, and the synthesis of high-purity silicon carbide powder is achieved.
Patent Information
- Application Number
- CN202422496064.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2025-08-08
- Estimated Expiration
- 2034-10-16
AI Technical Summary
In the prior art, the temperature in the middle of the crucible is relatively low relative to the side temperature, resulting in uneven temperature distribution, resulting in insufficient reaction of silicon carbide powder, resulting in problems of raw material loss and low purity.
The combined use of heating chamber and auxiliary heat chamber is adopted, combined with the agitation of the hollow shaft and argon injection, to achieve uniform temperature distribution and vacuum formation in the crucible, and promote uniform mixing and tumbling of the powder.
The temperature in the middle of the crucible is effectively increased, the powder mixing is ensured evenly, the powder loss caused by insufficient reaction is reduced, and the purity is improved, and the synthesis of high-purity silicon carbide powder is achieved.
Smart Images
Figure CN223197039U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of silicon carbide synthesis, and in particular to a silicon carbide powder synthesis device. Background Art
[0002] With the rapid development of science and technology, the pace of innovation in semiconductor materials has further accelerated. Following the first-generation semiconductors represented by Si and the second-generation semiconductors represented by GaAs, third-generation wide-bandgap semiconductors, represented by SiC, are gaining increasing attention. SiC offers advantages such as a wide bandgap, high critical breakdown field strength, high thermal conductivity, and high carrier saturation mobility. It is particularly suitable for the manufacture of high-frequency, high-power, radiation-resistant, and corrosion-resistant electronic devices, making it one of the most promising materials in the semiconductor field.
[0003] Currently, the main methods for synthesizing high-purity SiC powder used to grow single crystals are: CVD method and self-propagating synthesis method.
[0004] Although the CVD method can obtain silicon carbide powder with higher purity, it still needs to go through subsequent processes such as oxidation, pickling, and crushing, which is a complex process and has high costs.
[0005] The self-propagating synthesis method, on the other hand, uses silicon powder and carbon powder to react under argon at high temperatures to synthesize silicon carbide. This reaction is typically performed in a crucible. A mixture of carbon and silicon powders is poured into the crucible and then heated. This method results in a lower temperature in the center of the crucible relative to the sides, leading to uneven temperature distribution throughout the crucible. This in turn leads to incomplete reaction of the powder in the center and raw material loss.
[0006] To this end, the present application provides a silicon carbide powder synthesis device that can effectively increase the temperature in the middle of the crucible, promote uniform temperature distribution in the crucible, and effectively reduce powder loss and low purity caused by insufficient synthesis reaction in this area. Utility Model Content
[0007] The purpose of this application is to solve the problems existing in the prior art and to propose a silicon carbide powder synthesis device.
[0008] In order to achieve the above objectives, this application adopts the following technical solutions:
[0009] A silicon carbide powder synthesis device comprises a furnace body and a furnace cover; a heating chamber is provided in the furnace body, a crucible is installed in the heating chamber, and an auxiliary heating chamber communicating with the heating chamber is provided in the middle of the crucible; a hollow shaft is rotatably installed on the furnace cover, the hollow shaft is driven by a drive assembly, an argon tank is connected to the upper end of the hollow shaft, a one-way valve is provided on the hollow shaft, an exhaust pump is connected to the furnace cover, and a plurality of bent hollow tubes are provided in a circular array at the lower end of the hollow shaft, and the hollow tubes are communicated with the air pipe.
[0010] Preferably, an air pipe runs through the furnace cover, and the air pipe is connected to a gas collecting chamber arranged outside the furnace cover.
[0011] Preferably, a rotary joint is provided at the upper end of the hollow shaft, the rotary joint is connected to an air pump via a hose, and the air pump is connected to an argon tank via an electric control valve.
[0012] Preferably, the driving assembly includes a bracket arranged on the furnace cover, a motor is fastened to the bracket, a driving gear is fixed to the output shaft of the motor, and the driving gear is meshed with a driven gear fixed on the hollow shaft.
[0013] Preferably, a hydraulic rod is fastened to the side of the furnace body via a bracket, and the protruding end of the hydraulic rod is connected to the bracket.
[0014] Preferably, the hollow shaft is divided into a driving shaft rotatably mounted on the bracket and a driven shaft connected to the hollow tube, and the driving shaft and the driven shaft are fastened together via a flange.
[0015] Compared with the prior art, the present application provides a silicon carbide powder synthesis device with the following beneficial effects:
[0016] In this solution, the combined use of the heating chamber and the auxiliary heating chamber can effectively increase the temperature in the middle of the crucible; and the stirring of the hollow shaft can not only make the powder mixing more uniform and accelerate the exhaust of the bottom air to form a vacuum, but also make the powder churn, promote the uniform distribution of temperature in the crucible, and effectively reduce the powder loss and low purity caused by insufficient synthesis reaction in this area.
[0017] Other advantages, objectives and features of the present application will be described in part in the following description; and in part, will be apparent to those skilled in the art based on an examination of the following; or, may be taught from the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a cross-sectional schematic diagram of the furnace body and furnace cover in the fastened state of the present application.
[0019] Figure 2 This is a cross-sectional schematic diagram of the furnace cover of this application in the open state.
[0020] Figure 3 For this application Figure 2 A partial schematic diagram of point A.
[0021] Figure 4 This is a schematic diagram of the hollow shaft and hollow tube structure of this application.
[0022] Figure 5 This is a schematic diagram of the distribution of the crucible and auxiliary heating chamber of this application.
[0023] In the figure: 1. furnace body; 2. furnace cover; 3. hydraulic rod; 4. bracket; 5. motor; 6. driving gear; 7. driven gear; 8. hollow shaft; 9. rotating joint; 10. hollow tube; 11. vacuum pump; 12. gas collecting chamber; 13. embedded seal; 14. heating chamber; 15. auxiliary heating chamber; 16. electric heating component 1; 17. electric heating component 2; 18. powder; 19. crucible. DETAILED DESCRIPTION
[0024] The following is a combination of the appended examples of the present application Figure 1-5 , the technical solutions in the embodiments of the present application are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.
[0025] Example 1. In order to solve the problems existing in the prior art, this embodiment provides a silicon carbide powder synthesis device, including a furnace body 1 and a furnace cover 2; a heating chamber 14 is provided in the furnace body 1, a crucible 19 is installed in the heating chamber 14, and an auxiliary heating chamber 15 communicating with the heating chamber 14 is provided in the middle of the crucible 19; a hollow shaft 8 is axially rotated and installed on the furnace cover 2, the hollow shaft 8 is driven by a driving assembly, an argon tank is connected to the upper end of the hollow shaft 8, a one-way valve is provided on the hollow shaft 8, an exhaust pump 11 is connected to the furnace cover 2, and a plurality of bent hollow tubes 10 are arranged in a circular array at the lower end of the hollow shaft 8, and the hollow tubes 10 are communicated with the air pipe.
[0026] Principle details of this embodiment:
[0027] A silicon carbide powder synthesis device includes a furnace body 1 and a furnace cover 2. High-temperature resistant sealing rings are provided at the upper end of the furnace body 1 and the lower end of the furnace cover 2. The inner walls of the furnace body 1 and the furnace cover 2 are both provided with thermal insulation layers.
[0028] The furnace body 1 is provided with a heating chamber 14, in which a crucible 19 is mounted. The heating chamber 14 includes an electric heating assembly 16 arranged around the chamber wall, surrounding the crucible 19. The annular arrangement of the electric heating assemblies 16 ensures more uniform heating of the crucible 19.
[0029] An inverted test-tube-shaped cover is located in the center of crucible 19. Made of a heat-conducting material, the cover houses an auxiliary heating chamber 15. The crucible 19 is axially open, allowing the auxiliary heating chamber 15 within the cover to communicate with the heating chamber 14. Multiple sets of electric heating components 17 are also located within auxiliary heating chamber 15.
[0030] A hollow shaft 8 is axially mounted on the furnace cover 2, extending through the cover. The upper end of the hollow shaft 8, extending beyond the cover, is connected to a drive assembly, which drives the hollow shaft 8 for rotation. The upper end of the hollow shaft 8 is connected to an argon tank mounted on the cover 2. The lower end of the hollow shaft 8 has a circular array of multiple curved hollow tubes 10, which communicate with the gas pipe. A one-way valve is installed on the hollow shaft 8. An exhaust valve is also installed on the cover 2. The exhaust valve's exhaust port extends through the cover 2 and into the heating chamber 14, communicating with the crucible 19.
[0031] A temperature measuring instrument and a pressure measuring instrument are provided in the crucible 19 for real-time monitoring of the temperature and pressure in the crucible 19 , so as to facilitate temperature and pressure regulation.
[0032] In this embodiment, the electric heating component 1 16 and the electric heating component 2 17 are both electric heating wires.
[0033] According to the above technical solution:
[0034] During use, the first electric heating element 16 in the heating chamber 14 and the second electric heating element 17 in the auxiliary heating chamber 15 are first activated to preheat the crucible 19 until the temperature inside the crucible 19 reaches the desired temperature. The inside and outside of the crucible 19 are heated simultaneously, so that the powder 18 in the crucible 19 is heated more evenly.
[0035] Then, the furnace cover 2 is opened, and silicon powder and carbon powder are mixed in the required proportion and poured into the crucible 19 , and then the furnace cover 2 is closed and tightened.
[0036] The vacuum pump 11 is then started to pump air out. After a certain period of time, the argon tank and drive assembly are turned on again. The argon in the argon tank first flows into the hollow shaft 8, then into the hollow tube 10 and into the crucible 19 through the lower end of the hollow tube 10. Simultaneously, the drive assembly rotates the hollow shaft 8, stirring the powder 18 through the hollow tube 10. The stirring effect of the hollow tube 10 not only ensures a more complete mixing of the carbon powder and silicon powder and a more even heating, but also causes the powder 18 to turn. The lower end of the hollow tube 10 continuously injects argon, which drives the remaining air between the gaps in the bottom layer of the powder 18 upward, thereby being pumped out of the vacuum pump 11 to the outside. The argon tank is then turned off, and the drive assembly continues to rotate the hollow shaft 8, causing the argon between the powder 18 to continue to float upward and be discharged to the outside through the vacuum pump 11. The pressure gauge is checked until a high vacuum is reached in the crucible 19, and then the vacuum pump 11 is turned off, isolating the crucible 19 from the outside. Under high vacuum and high temperature conditions, carbon powder and silicon powder fully react to synthesize silicon carbide, and the silicon carbide powder synthesized under high vacuum conditions is used to grow silicon carbide single crystals, which have higher purity and excellent semi-insulating properties.
[0037] In this solution, the combined use of the heating chamber 14 and the auxiliary heating chamber 15 can effectively increase the temperature in the middle of the crucible 19; and the stirring of the hollow shaft 8 can not only make the powder 18 mixed more evenly and accelerate the discharge of the bottom air to form a vacuum, but also make the powder 18 churn, thereby promoting a uniform temperature distribution in the crucible 19, and effectively reducing the loss of powder 18 caused by insufficient synthesis reaction in this area and the problem of low purity.
[0038] In this embodiment, a pressure regulating valve is further provided on the furnace cover 2 for regulating the pressure change in the crucible 19 .
[0039] Embodiment 2, in a further embodiment of the present invention, an air pipe is passed through the furnace cover 2, and the air pipe is connected to an air collecting chamber 12 arranged outside the furnace cover 2 through an exhaust pump.
[0040] When argon is injected into the crucible 19 , the vacuum pump 11 is closed and the exhaust pump is opened to pump the argon into the gas collecting chamber 12 for storage and recovery so that it can be reused later, thereby reducing production costs.
[0041] Example 3, in a further embodiment of this scheme, a rotating joint 9 is provided at the upper end of the hollow shaft 8, and the rotating joint 9 is rotatably installed on the furnace cover 2. The rotating joint 9 is connected to an air pump via a hose, and the air pump is connected to the argon tank via an electric control valve.
[0042] At this time, the argon tank can be placed on the side of the furnace body 1 without rotating with the rotation of the hollow shaft 8, which can not only reduce the driving resistance load of the drive component; but also reduce the weight of the furnace cover 2, making it easier to open the furnace cover 2.
[0043] Example 4, in a further embodiment of the present scheme, the driving assembly includes a bracket 4 arranged on the furnace cover 2, a motor 5 is fastened to the bracket 4, a driving gear 6 is fixed on the output shaft of the motor 5, and the driving gear 6 is engaged with a driven gear 7 fixed on the hollow shaft 8.
[0044] The motor 5 can drive the hollow shaft 8 to rotate through the cooperation of the driving gear 6 and the driven gear 7, and is separated from the end of the hollow shaft 8, so as not to affect the injection of argon gas.
[0045] In a further embodiment of the present invention, a hydraulic rod 3 is fixed to the side of the furnace body 1 via a bracket 4, and the protruding end of the hydraulic rod 3 is connected to the bracket 4. The hydraulic rod 3 drives the furnace cover 2 to rise and fall, and then controls the opening of the crucible 19, saving manpower.
[0046] In a further embodiment of this solution, the hollow shaft 8 is divided into a drive shaft rotatably mounted on the bracket 4 and a driven shaft connected to the hollow tube 10. The drive shaft and the driven shaft are each provided with a flange on opposite ends, and the two flanges are fastened together by bolts. This makes the hollow shaft 8 divisible, facilitating disassembly, assembly, maintenance, and replacement.
[0047] In this embodiment, the lower end of the furnace cover 2 is provided with an embedded seal 13, the lower end of which is sunken at its axis. The embedded seal 13 seals against the end surface of the crucible 19, while the sunken portion of the embedded seal 13 is inserted into the crucible 19, thereby forming a tight connection between the crucible 19 and the furnace cover 2 and preventing pressure release.
[0048] In this solution, electric control valves are provided between the suction port of the vacuum pump 11 , the suction port of the exhaust pump, the suction port of the charging pump and the corresponding pipelines to control the sealing of the internal space of the furnace body 1 .
[0049] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solution and application concept of the present application within the technical scope disclosed in the present application, and they should be covered by the scope of protection of the present application.
[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.
[0051] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.
Claims
1. A silicon carbide powder synthesis device, characterized in that: The invention comprises a furnace body (1) and a furnace cover (2); a heating chamber (14) is provided in the furnace body (1), a crucible (19) is installed in the heating chamber (14), and an auxiliary heating chamber (15) communicating with the heating chamber (14) is provided in the middle of the crucible (19); a hollow shaft (8) is rotatably installed on the furnace cover (2), the hollow shaft (8) is driven by a driving assembly, an argon gas tank is connected to the upper end of the hollow shaft (8), a one-way valve is provided on the hollow shaft (8), an exhaust pump (11) is connected to the furnace cover (2), and a plurality of bent hollow tubes (10) are provided in a circular array at the lower end of the hollow shaft (8), and the hollow tubes (10) are communicated with the gas pipe.
2. A silicon carbide powder synthesis device according to claim 1, characterized in that: An air pipe runs through the furnace cover (2), and the air pipe is connected to a gas collecting chamber (12) arranged outside the furnace cover (2).
3. The silicon carbide powder synthesis device according to claim 1, characterized in that: A rotary joint (9) is provided at the upper end of the hollow shaft (8), and the rotary joint (9) is connected to an air pump via a hose, and the air pump is connected to an argon tank via an electric control valve.
4. The silicon carbide powder synthesis device according to claim 1, characterized in that: The drive assembly comprises a bracket (4) arranged on the furnace cover (2), a motor (5) is fastened to the bracket (4), a driving gear (6) is fixed to the output shaft of the motor (5), and the driving gear (6) is meshed with a driven gear (7) fixed to the hollow shaft (8).
5. The silicon carbide powder synthesis device according to claim 4, characterized in that: A hydraulic rod (3) is fastened and mounted on the side of the furnace body (1) via a bracket (4), and the protruding end of the hydraulic rod (3) is connected to the bracket (4).
6. The silicon carbide powder synthesis device according to claim 4, characterized in that: The hollow shaft (8) is divided into a driving shaft rotatably mounted on the bracket (4) and a driven shaft connected to the hollow tube (10), and the driving shaft and the driven shaft are fastened via a flange.