Microwave-assisted heating device for growth of silicon carbide
By using microwave-assisted heating devices in the growth of silicon carbide crystals, combined with medium frequency induction coils and high-temperature metal coatings, the problem of large radial temperature gradient of silicon carbide powder is solved, the temperature distribution uniformity and crystal growth quality are improved, and the temperature distribution is uniform, and the crystal growth quality is improved. Raw material utilization and crystal growth quality.
Patent Information
- Application Number
- CN202421189428.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-27
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2034-05-27
AI Technical Summary
In the existing silicon carbide crystal growth method, the induction heating of the medium frequency electromagnetic coil and the resistance heating of graphite heater lead to a large radial temperature gradient of silicon carbide powder, which affects the consistency of single crystal crystal quality, and is prone to multiple defects and raw material utilization. The rate decreases.
Using microwave-assisted heating device, the silicon carbide powder is heated from the outside and inside through the medium frequency induction coil and microwave device respectively to reduce the radial temperature gradient, and prevent microwave leakage and graphitization through high-temperature metal coating, optimize temperature distribution and thermal field Craft.
Improve the uniformity of temperature distribution of silicon carbide powder, improve the volatility consistency and crystal growth quality of gas phase components, reduce the crystallization of the central surface, improve the utilization rate of raw materials, and optimize the thermal field process by adjusting the microwave frequency, further improve the The quality of crystal growth.
Smart Images
Figure CN222294264U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of silicon carbide, in particular to a microwave-assisted heating device for growing silicon carbide. Background Art
[0002] Silicon carbide is a third-generation semiconductor material with strong radiation resistance, high thermal conductivity, high critical electric field and high saturation mobility. It has great advantages in the field of power devices and is widely used in new energy vehicles, photovoltaic power generation, railway transportation and power systems.
[0003] The more mature method for growing silicon carbide crystals in the industry is physical vapor transport (PVT). The principle is to use a certain temperature gradient setting to allow silicon carbide powder to sublimate and decompose at high temperature. The gaseous components are transported to the seed crystal located in the upper low-temperature zone under the action of the temperature gradient to deposit and crystallize. Since the growth temperature of silicon carbide crystals is above 2300°C, the growth conditions are harsh, the crystal growth rate is slow, and the control of temperature and pressure is high. In addition, silicon carbide has more than 250 crystal forms, and the commonly used substrate types in business are generally 4H-SiC, 6H-SiC, and 3C-SiC. The growth temperatures of these crystal forms are similar, and polymorphic defects are prone to occur during the growth process. Therefore, silicon carbide crystal growth has very high requirements for axial and radial temperature gradients.
[0004] There are two commonly used heating methods in the PVT method, medium-frequency electromagnetic coil induction heating and graphite heater resistance heating. Induction coil heating has become the mainstream heating method due to its high heating efficiency and fast heating speed; resistance heating has gradually emerged in the growth of large-size crystals due to its high temperature control accuracy.
[0005] However, both of these heating methods heat the crucible surface first, and then transfer the heat to the raw materials inside. As a result, the temperature of the powder near the crucible wall will be higher than that of the powder at the center, and the radial temperature gradient inside the powder will be large. Although resistance heating can optimize the radial temperature to a certain extent, it cannot fundamentally solve this problem. This problem is particularly evident when growing large-sized crystals. As the diameter of the crucible increases, the radial temperature gradient of the raw materials increases further, causing serious carbonization of the raw materials in the surrounding high-temperature zones. The sublimated gas is easily deposited in the low-temperature zone in the center of the powder to form polycrystals, which in turn hinders the volatilization of the gas phase components, affects the consistency of the single crystal crystallization quality, and easily causes defects such as encapsulation, microtubules and deformation, while causing a decrease in raw material utilization. Utility Model Content
[0006] The purpose of the utility model is to provide a microwave-assisted heating device for silicon carbide growth, which has the advantage of being able to introduce a microwave heating method and utilize the strong microwave absorption ability of silicon carbide to be heated from the inside, so that the silicon carbide powder is heated from the inside, thereby reducing the radial temperature gradient of the powder and optimizing the uniformity of its temperature distribution.
[0007] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a microwave-assisted heating device for silicon carbide growth, comprising a workbench and a silicon carbide crystal, a protective cover is fixedly connected to the middle end of the top of the workbench, a medium-frequency induction coil is fixedly installed in the inner cavity of the protective cover, a crucible barrel main body is placed at the bottom of the inner cavity of the protective cover, silicon carbide powder is placed at the bottom of the inner cavity of the crucible barrel main body, a porous graphite plate is placed between the middle end of the inner cavity of the crucible barrel main body and the top of the silicon carbide powder, a waveguide is fixedly connected to the lower end of the right side of the crucible barrel main body, and a microwave device is fixedly installed at the lower end of the waveguide.
[0008] As a preferred solution, the crucible barrel body comprises a base layer, and the inner surface of the base layer is coated with a high-temperature metal coating.
[0009] As a preferred embodiment, a crucible cover is placed on the top of the crucible barrel body, a handle is fixedly connected to the top of the crucible cover, and the top of the silicon carbide crystal is fixedly connected to the bottom of the crucible cover.
[0010] As a preferred solution, guide balls are movably connected around the top of the protective cover, the surface of the guide balls is movably connected to the upper end of the outer surface of the crucible barrel body, and the outer surface of the protective cover is covered with a heat insulation sleeve.
[0011] As a preferred solution, pillars are fixedly connected around the bottom of the workbench, a bottom plate is fixedly connected between the bottoms of the four pillars, and the bottom of the microwave device is placed at the middle end of the top of the bottom plate.
[0012] Compared with the prior art, the beneficial effects of the utility model are as follows:
[0013] 1. The utility model can heat the silicon carbide powder from the outside and inside of the crucible barrel body respectively through the arrangement of the microwave device and the medium frequency induction coil, thereby improving the uniformity of the temperature distribution inside the silicon carbide powder and reducing the radial temperature gradient. On the one hand, the consistency of the volatilization and gas phase components of the silicon carbide powder is improved, which is beneficial to the improvement of the crystal growth quality. On the other hand, the central surface crystallization of the silicon carbide powder caused by the radial temperature gradient can be reduced, and the utilization rate of the powder can be improved. Moreover, the microwave device can adjust the frequency of the emitted microwaves and regulate the heating effect, which can effectively optimize the thermal field process and further improve the crystal growth quality.
[0014] 2. The utility model, through the provision of a high-temperature metal coating, can effectively prevent microwave leakage from the inside of the crucible barrel body during operation, and at the same time, the microwaves can be completely reflected or absorbed inside the crucible barrel body. On the other hand, it can protect the inside of the crucible barrel body from graphitization, reduce carbon particles in the gas phase components, and improve the quality of crystal growth. The provision of the crucible cover facilitates protection of the top of the crucible barrel body. The provision of guide balls can effectively support and guide the surroundings of the upper end of the crucible barrel body, ensuring that the crucible barrel body can be accurately placed in the center area of the intermediate frequency induction coil. The provision of a workbench, columns and bottom plate achieves the purpose of supporting the microwave device and the protective cover. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a three-dimensional diagram of the utility model;
[0016] Figure 2 This is a schematic diagram of the cross-sectional structure of the protective cover of the utility model;
[0017] Figure 3 This is a schematic diagram of the main structure of the crucible barrel of the utility model.
[0018] In the figure: 1. workbench; 2. bottom plate; 3. microwave device; 4. column; 5. waveguide; 6. protective cover; 7. insulation sleeve; 8. crucible cover; 9. handle; 10. silicon carbide crystal; 11. crucible barrel body; 111. base layer; 112. high-temperature metal coating; 12. guide ball; 13. porous graphite plate; 14. medium-frequency induction coil; 15. silicon carbide powder. DETAILED DESCRIPTION
[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0020] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.
[0021] Embodiment 1:
[0022] See also Figure 1-Figure 2As shown, the utility model provides a microwave-assisted heating device for silicon carbide growth, comprising a workbench 1 and a silicon carbide crystal 10, a protective cover 6 is fixedly connected to the middle end of the top of the workbench 1, a medium-frequency induction coil 14 is fixedly installed in the inner cavity of the protective cover 6, a crucible barrel main body 11 is placed at the bottom of the inner cavity of the protective cover 6, silicon carbide powder 15 is placed at the bottom of the inner cavity of the crucible barrel main body 11, a porous graphite plate 13 is placed between the middle end of the inner cavity of the crucible barrel main body 11 and the top of the silicon carbide powder 15, a waveguide 5 is fixedly connected to the lower end of the right side of the crucible barrel main body 11, and a microwave device 3 is fixedly installed at the lower end of the waveguide 5.
[0023] In the present technical solution, by providing the microwave device 3 and the medium frequency induction coil 14, the silicon carbide powder 15 can be heated from the outside and the inside of the crucible barrel body 11 respectively, thereby improving the uniformity of the temperature distribution inside the silicon carbide powder 15 and reducing the radial temperature gradient. On the one hand, the consistency of the volatilization and gas phase components of the silicon carbide powder 15 is improved, which is beneficial to the improvement of the crystal growth quality. On the other hand, the crystallization of the central surface of the silicon carbide powder 15 caused by the radial temperature gradient can be reduced, thereby improving the utilization rate of the powder. Moreover, the microwave device 3 can adjust the frequency of the emitted microwaves and regulate the heating effect, thereby effectively optimizing the thermal field process and further improving the crystal growth quality.
[0024] Embodiment 2:
[0025] On the basis of embodiment 1, the present invention is as follows Figure 1-Figure 3 As shown, a crucible barrel main body 11 is disclosed, comprising a base layer 111, an inner surface of the base layer 111 is coated with a high-temperature metal coating 112, a crucible cover 8 is placed on the top of the crucible barrel main body 11, a handle 9 is fixedly connected to the top of the crucible cover 8, the top of the silicon carbide crystal 10 is fixedly connected to the bottom of the crucible cover 8, guide balls 12 are movably connected to the four sides of the top of the protective cover 6, the surface of the guide balls 12 is movably connected to the upper end of the outer surface of the crucible barrel main body 11, the outer surface of the protective cover 6 is provided with an insulating sleeve 7, columns 4 are fixedly connected to the four sides of the bottom of the workbench 1, a bottom plate 2 is fixedly connected between the bottoms of the four columns 4, and the bottom of the microwave device 3 is placed at the middle end of the top of the bottom plate 2.
[0026] In the present technical solution, by setting the high-temperature metal coating 112, on the one hand, it is effective to prevent microwave leakage from the inside of the crucible barrel main body 11 during operation, and at the same time, the microwave is completely reflected or absorbed inside the crucible barrel main body 11. On the other hand, it can protect the inside of the crucible barrel main body 11 from being graphitized, reduce carbon particles in the gas phase components, and improve the quality of crystal growth. By setting the crucible cover 8, it is convenient to protect the top of the crucible barrel main body 11. By setting the guide balls 12, it is possible to effectively support and guide the surroundings of the upper end of the crucible barrel main body 11, ensuring that the crucible barrel main body 11 can be accurately placed in the center area of the intermediate frequency induction coil 14. By setting the workbench 1, the column 4 and the bottom plate 2, the purpose of supporting the microwave device 3 and the protective cover 6 is achieved.
[0027] The working principle of the utility model is as follows: through the arrangement of the microwave device 3 and the medium frequency induction coil 14, the silicon carbide powder 15 can be heated from the outside and the inside of the crucible barrel body 11 respectively, thereby improving the uniformity of the temperature distribution inside the silicon carbide powder 15 and reducing the radial temperature gradient. On the one hand, the consistency of the volatilization and gas phase components of the silicon carbide powder 15 is improved, which is beneficial to the improvement of the crystal growth quality. On the other hand, the crystallization of the central surface of the silicon carbide powder 15 caused by the radial temperature gradient can be reduced, thereby improving the utilization rate of the powder. Moreover, the microwave device 3 can adjust the frequency of the emitted microwaves and regulate the heating effect, thereby effectively optimizing the thermal field process and further improving the crystal growth quality.
[0028] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and ratio of various elements, and parameter values (e.g., temperature, pressure, etc.), installation arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present utility model. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of performing the function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the present invention is not limited to a specific embodiment, but extends to various modifications that still fall within the scope of the appended claims.
[0029] Additionally, in order to provide a concise description of example embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.
[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit the protection scope of the utility model. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the utility model.
Claims
1. A microwave-assisted heating device for growing silicon carbide, comprising a workbench (1) and a silicon carbide crystal (10), characterized in that: A protective cover (6) is fixedly connected to the middle end of the top of the workbench (1), a medium-frequency induction coil (14) is fixedly installed in the inner cavity of the protective cover (6), a crucible barrel body (11) is placed at the bottom of the inner cavity of the protective cover (6), silicon carbide powder (15) is placed at the bottom of the inner cavity of the crucible barrel body (11), a porous graphite plate (13) is placed between the middle end of the inner cavity of the crucible barrel body (11) and the top of the silicon carbide powder (15), a waveguide (5) is fixedly connected to the lower end of the right side of the crucible barrel body (11), and a microwave device (3) is fixedly installed at the lower end of the waveguide (5).
2. The microwave-assisted heating device for silicon carbide growth according to claim 1, characterized in that: The crucible barrel body (11) comprises a base layer (111), and the inner surface of the base layer (111) is coated with a high-temperature metal coating (112).
3. The microwave-assisted heating device for silicon carbide growth according to claim 1, characterized in that: A crucible cover (8) is placed on the top of the crucible barrel body (11), a handle (9) is fixedly connected to the top of the crucible cover (8), and the top of the silicon carbide crystal (10) is fixedly connected to the bottom of the crucible cover (8).
4. The microwave-assisted heating device for silicon carbide growth according to claim 1, characterized in that: The top of the protective cover (6) is movably connected to guide balls (12) on all sides, and the surface of the guide balls (12) is movably connected to the upper end of the outer surface of the crucible barrel body (11). The outer surface of the protective cover (6) is covered with a heat insulation sleeve (7).
5. The microwave-assisted heating device for silicon carbide growth according to claim 1, characterized in that: The bottom of the workbench (1) is fixedly connected to columns (4) on all sides, the bottoms of the four columns (4) are fixedly connected to a base plate (2), and the bottom of the microwave device (3) is placed at the middle end of the top of the base plate (2).