Silicon carbide composite seed crystal and silicon carbide seed crystal assembly
By designing a silicon carbide composite seed crystal, the problems of slow growth rate and small thickness of silicon carbide crystals were solved, enabling the growth of large-diameter, high-thickness, and low-cost silicon carbide crystals while ensuring crystal quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU INST OF ADVANCED SEMICON CO LTD
- Filing Date
- 2025-04-27
- Publication Date
- 2026-05-12
AI Technical Summary
Silicon carbide crystals grow slowly, have small thickness, and poor internal quality, making it impossible to obtain electronic-grade silicon carbide crystals. This is mainly due to the low thermal conductivity of silicon carbide seed crystals, which prevents the formation of large vertical temperature gradients.
A silicon carbide composite seed crystal is used, which includes a heat dissipation substrate, a transition layer and a silicon carbide seed crystal. By establishing a temperature gradient between a heat dissipation substrate with high thermal conductivity, a transition layer with low thermal conductivity and a silicon carbide seed crystal with even lower thermal conductivity, and using the transition layer as a thermal stress buffer layer, interface cracks are reduced, and large-diameter and thick silicon carbide crystals can be grown.
The growth rate of silicon carbide crystals in both vertical and horizontal directions was increased, enabling the growth of silicon carbide crystals with a thickness of more than 50 mm, reducing growth costs, and ensuring crystal quality.
Smart Images
Figure CN224227290U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of semiconductor material preparation, and in particular to silicon carbide composite seed crystals and silicon carbide seed crystal components including the silicon carbide composite seed crystals. Background Technology
[0002] Silicon carbide crystal materials, due to their wide bandgap, high thermal conductivity, and high breakdown field strength, are widely used in electric vehicles, photovoltaics, radio frequency communications, and other fields, making them one of the most important third-generation semiconductor materials. Because of their high optical refractive index and high thermal conductivity, silicon carbide crystals are currently being used as optical chips in augmented reality (AR) glasses, with a very broad market application prospect.
[0003] Silicon carbide crystals are typically produced as large-size, commercially viable bulk crystals using PVT (Physical Vapor Transport) and LPE (Liquid Phase Epitaxy). However, the growth rate is significantly lower than that of silicon crystals. Currently, silicon carbide crystals are mainly available in 6-inch and 8-inch diameters, with a single crystal growth cycle of approximately 7-10 days. The growth rate is extremely slow; most domestic manufacturers achieve growth rates of 100-150 micrometers per hour, resulting in crystal thicknesses of only 20-25 mm. The yield rate is far lower than that of mature monocrystalline silicon growth, and the growth process is often described as a "black box" operation with opaque ingots, making timely quality feedback impossible. Wolfspeed, an American company, has achieved a world-leading growth rate of over 300 micrometers per hour for its 8-inch silicon carbide substrates, reaching thicknesses of up to 60 mm.
[0004] The slow growth rate of silicon carbide crystals is due to the poor physical properties of the silicon carbide seed crystals used in both physical vapor deposition (PVD) and flux-fluid liquid phase (CFLP) methods. Traditional seed crystals consist of a certain thickness of silicon carbide single crystal material. The thermal conductivity of silicon carbide single crystal material is only 490 W / (m·K). Factors affecting the thermal conductivity of silicon carbide single crystals include impurities and crystal structure defects. For example, an increase in nitrogen content reduces the thermal conductivity of the material, and the presence of crystal structure defects leads to a decrease in thermal conductivity. During crystal growth, the temperature gradient is the intrinsic driving force for single crystal crystallization and a key factor determining the crystal growth rate. There is a close positive correlation between crystal growth rate and temperature gradient; a large temperature gradient results in a faster crystallization rate, and vice versa. The low thermal conductivity of silicon carbide is unfavorable for forming the large vertical temperature gradient required for silicon carbide crystal growth. Therefore, silicon carbide crystals grow slowly and have small crystal thicknesses, meaning they are not long and thick, typically only 20–25 mm thick, or, in cases of long and thick crystals, the internal quality is poor, making it impossible to obtain electronic-grade silicon carbide crystals. Summary of the Invention
[0005] The purpose of this invention is to provide a silicon carbide composite seed crystal and a silicon carbide seed crystal assembly to solve the problem that the low thermal conductivity of silicon carbide material is not conducive to the formation of silicon carbide crystals, which requires a large temperature gradient in the vertical direction. This results in slow growth rate and very small crystal thickness, typically only 20-25 mm, or poor internal quality when the crystal is thick, making it impossible to obtain electronic-grade silicon carbide crystals. The silicon carbide composite seed crystal provided by this invention can achieve the growth of large-diameter, high-thickness, and low-cost silicon carbide crystals while ensuring the growth quality of the silicon carbide crystals.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A first aspect of this utility model provides a silicon carbide composite seed crystal, comprising:
[0008] Heat sink substrate;
[0009] A transition layer is disposed on the heat dissipation substrate;
[0010] A silicon carbide seed crystal is disposed on the side of the transition layer away from the heat dissipation substrate;
[0011] The thermal conductivity of the transition layer is greater than that of the silicon carbide seed crystal, and the thermal conductivity of the transition layer is less than that of the heat dissipation substrate.
[0012] Compared with existing technologies, the beneficial effects of this invention are as follows: using a transition layer as a thermal stress buffer layer can reduce interface cracks or peeling caused by the difference in thermal expansion coefficients between the heat dissipation substrate and the silicon carbide seed crystal. By establishing a temperature gradient of a heat dissipation substrate with high thermal conductivity, a transition layer with low thermal conductivity, and a silicon carbide seed crystal with even lower thermal conductivity, heat at the silicon carbide seed crystal can be quickly transferred away in both vertical and horizontal directions. This results in a large temperature gradient in both the vertical and horizontal directions of the silicon carbide composite seed crystal, which not only increases the growth rate of the silicon carbide crystal in the vertical direction, facilitating the growth of silicon carbide crystals with a thickness of more than 50 mm, but also increases the growth rate of the silicon carbide crystal in the horizontal direction, which is beneficial for the diameter expansion during silicon carbide crystal growth and facilitates the growth of large-diameter silicon carbide crystals. This greatly reduces the growth cost of silicon carbide materials. In summary, the above-mentioned silicon carbide composite seed crystal achieves the growth of large-diameter, high-thickness, and low-cost silicon carbide crystals while ensuring the growth quality of the silicon carbide crystals.
[0013] In some possible implementations of the first aspect, the silicon surface of the transition layer is provided with a plurality of first groove microchannels, and the silicon surface of the silicon carbide seed crystal is provided with a first protrusion microchannel corresponding one-to-one with each of the first groove microchannels.
[0014] In some possible embodiments of the first aspect, the width of the first groove microchannel is 5 to 10 μm; and / or, the depth of the first groove microchannel is 30 to 50 μm; and / or, the lateral spacing of the first groove microchannel is 5 to 10 mm; and / or, all the first groove microchannels are connected end to end in sequence and distributed in a vortex shape.
[0015] In some possible embodiments of the first aspect, the silicon surface of the silicon carbide seed crystal is provided with a plurality of second groove microchannels, and the silicon surface of the transition layer is provided with a second protrusion microchannel corresponding one-to-one with each of the second groove microchannels.
[0016] In some possible embodiments of the first aspect, the width of the second groove microchannel is 5 to 10 μm; and / or, the depth of the second groove microchannel is 30 to 50 μm; and / or, the lateral spacing of the second groove microchannel is 5 to 10 mm; and / or, all the second groove microchannels are connected end to end in sequence and are distributed in a vortex shape.
[0017] In some possible embodiments of the first aspect, the heat dissipation substrate is a diamond substrate, and the transition layer is a silicon carbide transition layer; the surface of the diamond substrate is bonded to the carbon surface of the silicon carbide transition layer, and the silicon surface of the silicon carbide transition layer is bonded to the silicon surface of the silicon carbide seed crystal; the crystal form of the silicon carbide material in the silicon carbide transition layer is different from the crystal form of the silicon carbide material in the silicon carbide seed crystal.
[0018] In some possible embodiments of the first aspect, the heat dissipation substrate is single-crystal diamond or polycrystalline diamond; and / or, the thickness of the heat dissipation substrate is 300-500 μm; and / or, the thickness of the heat dissipation substrate is less than or equal to two-thirds of the thickness of the silicon carbide composite seed crystal, and the thickness of the heat dissipation substrate is greater than or equal to one-half the thickness of the silicon carbide composite seed crystal; and / or, the surface roughness of the heat dissipation substrate is less than a first preset roughness; wherein the value of the first preset roughness ranges from 1 to 5 nm.
[0019] In some possible embodiments of the first aspect, the silicon carbide material in the silicon carbide transition layer has a 3C, 4H, 6H or 15R crystal form; and / or, the thickness of the silicon carbide transition layer is 10 to 50 μm;
[0020] And / or, the surface roughness of the silicon surface of the silicon carbide transition layer is less than a second preset roughness; wherein the value of the second preset roughness ranges from 1 to 5 nm; and / or, the silicon carbide transition layer is formed by epitaxial growth or heterobonding.
[0021] In some possible embodiments of the first aspect, the silicon carbide material in the silicon carbide seed crystal has a 3C, 4H, 6H, or 15R crystal form; and / or, the thickness of the silicon carbide seed crystal is 100–200 μm; and / or, the thickness of the silicon carbide seed crystal is less than one-third of the thickness of the silicon carbide composite seed crystal; and / or, the silicon carbide seed crystal is formed by epitaxial growth or heterobonding.
[0022] A second aspect of this utility model provides a silicon carbide seed crystal assembly, comprising:
[0023] Silicon carbide seed crystal holder;
[0024] The first aspect is silicon carbide composite seed crystal;
[0025] An adhesive layer is disposed between the silicon carbide seed crystal holder and the heat dissipation substrate in the silicon carbide composite seed crystal, for bonding the silicon carbide composite seed crystal to the silicon carbide seed crystal holder. Attached Figure Description
[0026] Figure 1 A schematic diagram of the structure of the silicon carbide composite seed crystal provided by this utility model;
[0027] Figure 2 A schematic diagram of the fan-shaped pattern structure of the first grooved microchannel provided by this utility model;
[0028] Figure 3 A schematic diagram of the circular pattern structure of the first grooved microchannel provided by this utility model;
[0029] Figure 4 A schematic diagram of the rectangular pattern structure of the first grooved microchannel provided by this utility model;
[0030] Figure 5 A schematic diagram of the vortex-shaped mosquito coil pattern structure of the first protruding microchannel provided by this utility model;
[0031] Figure 6 A schematic diagram of the structure of the silicon carbide seed crystal assembly provided by this utility model.
[0032] In the figure, 10 is the silicon carbide composite seed crystal; 11 is the heat dissipation substrate; 12 is the transition layer; 13 is the silicon carbide seed crystal; 20 is the adhesive layer; and 30 is the silicon carbide seed crystal support. Detailed Implementation
[0033] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore repeated descriptions of them will be omitted.
[0034] The terms used to describe position and direction in this utility model are illustrated with the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this utility model.
[0035] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of the silicon carbide composite seed crystal 10 provided by the present invention. The silicon carbide composite seed crystal 10 includes a heat dissipation substrate 11, a transition layer 12 and a silicon carbide seed crystal 13.
[0036] A transition layer 12 is disposed on a heat dissipation substrate 11, and a silicon carbide seed crystal 13 is disposed on the side of the transition layer 12 away from the heat dissipation substrate 11. Specifically, the thermal conductivity of the transition layer 12 is greater than that of the silicon carbide seed crystal 13, and the thermal conductivity of the transition layer 12 is less than that of the heat dissipation substrate 11; the transition layer 12 serves as a thermal stress buffer layer to reduce interface cracks or peeling caused by differences in thermal expansion coefficients.
[0037] By establishing a temperature gradient consisting of a high thermal conductivity heat dissipation substrate 11, a low thermal conductivity transition layer 12, and an even lower thermal conductivity silicon carbide seed crystal 13, heat at the silicon carbide seed crystal 13 can be rapidly transferred out along the vertical and horizontal directions. This results in a large temperature gradient in the vertical and horizontal directions at the silicon carbide composite seed crystal 10. This not only increases the growth rate of silicon carbide crystals in the vertical direction, which is beneficial for growing silicon carbide crystals with a thickness of more than 50 mm, but also increases the growth rate of silicon carbide crystals in the horizontal direction, which is beneficial for increasing the diameter of silicon carbide crystals during growth and makes it easier to grow large-diameter silicon carbide crystals, thus greatly reducing the growth cost of silicon carbide materials.
[0038] The aforementioned silicon carbide composite seed crystal 10 can achieve the growth of silicon carbide crystals with large diameter, high thickness, and low cost, while also ensuring the growth quality of silicon carbide crystals.
[0039] Furthermore, in a preferred embodiment of this invention, the heat dissipation substrate 11 is a diamond substrate, and the transition layer 12 is a silicon carbide transition layer. The surface of the diamond substrate is bonded to the carbon surface of the silicon carbide transition layer, and the silicon surface of the silicon carbide transition layer is bonded to the silicon surface of the silicon carbide seed crystal 13.
[0040] By combining the surface of the diamond substrate, i.e., the carbon surface, with the carbon surface of the silicon carbide transition layer, and the silicon surface of the silicon carbide transition layer with the silicon surface of the silicon carbide seed crystal 13, the interfacial stress can be reduced and the bonding strength of the silicon carbide composite seed crystal 10 can be enhanced.
[0041] Furthermore, the silicon carbide material in the silicon carbide transition layer has a crystal form of 3C, 4H, 6H or 15R, etc.; the silicon carbide material in the silicon carbide seed crystal 13 has a crystal form of 3C, 4H, 6H or 15R, etc.
[0042] It should be noted that the crystal form of the silicon carbide material in the silicon carbide transition layer is different from that of the silicon carbide material in the silicon carbide seed crystal 13. Preferably, in this embodiment, the silicon carbide material in the silicon carbide transition layer is in the 3C crystal form, and the silicon carbide material in the silicon carbide seed crystal 13 is in the 4H crystal form.
[0043] The thermal conductivity of diamond substrates is 2000–2200 W / (m·K), that of 4H-type silicon carbide material is 490 W / (m·K), and that of 3C-type silicon carbide material is 500 W / (m·K). This allows for the establishment of a temperature gradient between the diamond substrate, the 3C-type silicon carbide transition layer, and the 4H-type silicon carbide seed crystal. Currently, silicon carbide crystal growth is based on 4H-type silicon carbide seed crystals. Since silicon carbide devices are fabricated by growing silicon carbide crystals on 4H-type seed crystals, the crystal form of the seed crystal and the silicon carbide crystal to be grown must be consistent to facilitate the growth of high-quality silicon carbide crystals and ensure crystal quality.
[0044] Furthermore, in some embodiments, the thickness of the heat dissipation substrate 11 is 300-500 μm, for example, it can be 300 μm, 350 μm, 400 μm, 450 μm or 500 μm; the thickness of the silicon carbide transition layer is 10-50 μm, for example, it can be 10 μm, 20 μm, 30 μm, 40 μm or 50 μm; the thickness of the silicon carbide seed crystal 13 is 100-200 μm, for example, it can be 100 μm, 120 μm, 150 μm, 180 μm or 200 μm.
[0045] It should be noted that the thickness of the heat dissipation substrate 11 is less than or equal to two-thirds of the thickness of the silicon carbide composite seed crystal 10, and the thickness of the heat dissipation substrate 11 is greater than or equal to one-half the thickness of the silicon carbide composite seed crystal 10; and / or the thickness of the silicon carbide seed crystal 13 is less than one-third of the thickness of the silicon carbide composite seed crystal 10. The overall thermal conductivity of the silicon carbide composite seed crystal 10 within this thickness range is more than 40% higher than that of the pure silicon carbide seed crystal 13, and the temperature gradient established by the silicon carbide composite seed crystal 10 increases by 15-20% in the vertical direction and by 10% in the horizontal direction.
[0046] Preferably, the thickness of the heat dissipation substrate 11 is 300um, the thickness of the silicon carbide transition layer is 10um, and the thickness of the silicon carbide seed crystal 13 is 100um. The silicon carbide composite seed crystal 10 with this thickness has the thinnest thickness.
[0047] Furthermore, in some embodiments, the surface roughness of the heat dissipation substrate 11 is less than a first preset roughness; wherein the value of the first preset roughness ranges from 1 to 5 nm; the first preset roughness can be, for example, 1 nm, 2 nm, 3 nm, 4 nm, or 5 nm. And / or, the surface roughness of the silicon surface of the silicon carbide transition layer is less than a second preset roughness; wherein the value of the second preset roughness ranges from 1 to 5 nm; the second preset roughness can be, for example, 1 nm, 2 nm, 3 nm, 4 nm, or 5 nm. Preferably, the first preset roughness is 1 nm, and the second roughness is 1 nm.
[0048] The first and second preset roughness values within this range can promote the physical bonding between the heat dissipation substrate 11 and the silicon carbide transition layer at the atomic level, ensuring the bonding strength of the silicon carbide composite seed crystal 10.
[0049] Furthermore, in some embodiments, the silicon carbide transition layer is formed by epitaxial growth or heterobonding. And / or, the silicon carbide seed crystal 13 is formed by epitaxial growth or heterobonding.
[0050] Epitaxial growth and heterogeneous bonding processes enable silicon and carbon atoms in the silicon carbide transition layer to form covalent bonds with silicon atoms in the silicon carbide seed crystal 13 and carbon atoms in the diamond substrate, respectively, ensuring the growth quality of the silicon carbide composite seed crystal 10.
[0051] Furthermore, as a preferred embodiment of this utility model, in conjunction with Figures 1 to 4 As shown, the silicon surface of the transition layer 12 is provided with a plurality of first groove microchannels 121; the shape of the first groove microchannels 121 can be fan-shaped, circular, rectangular or other shapes; the number of first groove microchannels 121 can be set according to specific application needs, and all first groove microchannels 121 can be uniformly disposed on the silicon surface of the transition layer 12. The silicon surface of the silicon carbide seed crystal 13 is provided with first protruding microchannels corresponding one-to-one with each first groove microchannel 121.
[0052] It should be noted that the first protruding microchannel can be embedded in the first grooved microchannel 121; the corresponding interlocking of the first protruding microchannel and the first grooved microchannel 121 can increase the contact surface area between the silicon carbide seed crystal 13 and the silicon carbide transition layer, enhance the heat transfer capability of the silicon carbide seed crystal 13 and the silicon carbide transition layer during the growth process, thereby establishing a larger temperature gradient in the vertical and horizontal directions.
[0053] In some embodiments, the width of the first raised microchannel and the first recessed microchannel 121 is 5–10 μm, for example, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm; and / or, the depth of the first raised microchannel and the first recessed microchannel 121 is 30–50 μm, for example, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm. Preferably, the width of the first raised microchannel and the first recessed microchannel 121 is 10 μm, and the depth of the first raised microchannel and the first recessed microchannel 121 is 50 μm.
[0054] The first protruding microchannel and the first groove microchannel 121 with the aforementioned width and depth range enable the overall thermal conductivity of the silicon carbide composite seed crystal 10 to be more than 30% higher than that of the pure silicon carbide seed crystal 13. The temperature gradient established by the silicon carbide composite seed crystal 10 increases by 10% in the vertical direction and by 10% in the horizontal direction.
[0055] For preferred options, please refer to the appendix. Figure 5 As shown, the ends of all the first grooved microchannels 121 are connected sequentially and arranged in a vortex pattern (mosquito coil pattern); similarly, the ends of all the first raised microchannels are connected sequentially and arranged in a vortex pattern (mosquito coil pattern). The lateral spacing between the first grooved microchannels 121 and the first raised microchannels is 5–10 mm, for example, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. Preferably, the lateral spacing between the first grooved microchannels 121 and the first raised microchannels is 5 mm.
[0056] The first protruding microchannel and the first groove microchannel 121 within the aforementioned lateral spacing range have a combined thermal conductivity of silicon carbide composite seed crystal 10 that is more than 20% higher than that of pure silicon carbide seed crystal. The temperature gradient established by the silicon carbide composite seed crystal 10 is increased by 15% in the vertical direction and by 15% in the horizontal direction.
[0057] In another preferred embodiment of the present invention, the silicon surface of the silicon carbide seed crystal 13 is provided with a plurality of second groove microchannels, and the silicon surface of the transition layer 12 is provided with a second protrusion microchannel corresponding to each of the second groove microchannels.
[0058] It should be noted that the second protruding microchannel can be embedded in the second grooved microchannel; the corresponding interlocking of the second protruding microchannel and the second grooved microchannel can increase the contact surface area between the silicon carbide seed crystal 13 and the silicon carbide transition layer, enhance the heat transfer capability of the silicon carbide seed crystal 13 and the silicon carbide transition layer during the growth process, thereby establishing a larger temperature gradient in the vertical and horizontal directions.
[0059] In some embodiments, the width of the second raised microchannel and the second grooved microchannel is 5–10 μm, for example, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm; and / or, the depth of the second raised microchannel and the second grooved microchannel is 30–50 μm, for example, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm. Preferably, the width of the second raised microchannel and the second grooved microchannel is 9 μm, and the depth of the second raised microchannel and the second grooved microchannel is 45 μm.
[0060] The second protruding microchannel and the second groove microchannel with the aforementioned width and depth range enable the overall thermal conductivity of the silicon carbide composite seed crystal 10 to be more than 30% higher than that of the pure silicon carbide seed crystal 13. The temperature gradient established by the silicon carbide composite seed crystal 10 is increased by 10% in the vertical direction and by 10% in the horizontal direction.
[0061] Preferably, all the second grooved microchannels and all the second protruding microchannels are sequentially connected end-to-end and distributed in a vortex pattern (mosquito coil pattern). The lateral spacing between the second protruding microchannels and the second grooved microchannels is 5-10 mm, for example, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. Preferably, the lateral spacing between the second protruding microchannels and the second grooved microchannels is 9 mm.
[0062] The second protruding microchannel and the second groove microchannel within the aforementioned lateral spacing range have a combined thermal conductivity of silicon carbide composite seed crystal 10 that is more than 20% higher than that of pure silicon carbide seed crystal 13. The temperature gradient established by the silicon carbide composite seed crystal 10 is increased by 15% in the vertical direction and by 15% in the horizontal direction.
[0063] Understandably, the shape of the second groove microchannel is similar to the shape of the first groove microchannel 121, for example: Figures 2 to 4 As shown. The shapes of the first raised microchannel and the second raised microchannel are similar to the shape of the first grooved microchannel 121, for example: Figures 2 to 4 As shown; the difference is that the first raised microchannel and the second raised microchannel are raised structures, while the first grooved microchannel 121 is a grooved structure.
[0064] The second aspect of this embodiment can be found in [link to embodiment]. Figure 6 , Figure 6 This is a schematic diagram of the structure of the silicon carbide seed crystal assembly provided by this utility model. The silicon carbide seed crystal assembly includes a silicon carbide seed crystal holder 30, the silicon carbide composite seed crystal 10 described in the first aspect, and an adhesive layer 20. The adhesive layer 20 is disposed between the silicon carbide seed crystal holder 30 and the heat dissipation substrate 11 in the silicon carbide composite seed crystal 10, and is used to bond the silicon carbide composite seed crystal 10 to the silicon carbide seed crystal holder 30.
[0065] Therefore, in this silicon carbide seed crystal 13 assembly, the transition layer 12 is in contact with the silicon carbide seed crystal 13 body. The two are homogeneous materials with similar coefficients of thermal expansion and similar degrees of thermal expansion and contraction with temperature changes. They will not crack or fall off due to temperature changes during processing, and have little impact on the internal stress of the silicon carbide seed crystal 13 body. At the same time, both the silicon carbide transition layer 12 and the diamond substrate are high-temperature resistant and dense film layers, which can effectively prevent back-side evaporation problems and improve the quality of the grown crystal.
[0066] In this silicon carbide seed crystal assembly, by establishing a temperature gradient between a high thermal conductivity heat dissipation substrate 11, a low thermal conductivity transition layer 12, and an even lower thermal conductivity silicon carbide seed crystal 13, heat at the silicon carbide seed crystal 13 can be rapidly transferred out along the vertical and horizontal directions. This results in a large temperature gradient in the vertical and horizontal directions of the silicon carbide composite seed crystal 10. This not only increases the growth rate of the silicon carbide crystal in the vertical direction, which is beneficial for growing silicon carbide crystals with a thickness of more than 50 mm, but also increases the growth rate of the silicon carbide crystal in the horizontal direction, which is beneficial for the diameter expansion during the growth of the silicon carbide crystal, making it easier to achieve the growth of large-diameter silicon carbide crystals and greatly reducing the growth cost of silicon carbide materials. In summary, the silicon carbide composite seed crystal 10 prepared by the above method can achieve the growth of large-diameter, high-thickness, and low-cost silicon carbide crystals while ensuring the growth quality of silicon carbide crystals.
[0067] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and alterations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention, and all such changes should fall within the protection scope of the claims of the present invention.
Claims
1. A silicon carbide composite seed crystal, characterized in that, include: Heat sink substrate; A transition layer is disposed on the heat dissipation substrate; A silicon carbide seed crystal is disposed on the side of the transition layer away from the heat dissipation substrate; The thermal conductivity of the transition layer is greater than that of the silicon carbide seed crystal, and the thermal conductivity of the transition layer is less than that of the heat dissipation substrate.
2. The silicon carbide composite seed crystal according to claim 1, characterized in that, The silicon surface of the transition layer is provided with a plurality of first groove microchannels, and the silicon surface of the silicon carbide seed crystal is provided with a first protrusion microchannel corresponding one-to-one with each of the first groove microchannels.
3. The silicon carbide composite seed crystal according to claim 2, characterized in that, The width of the first groove microchannel is 5–10 μm; And / or, the depth of the first groove microchannel is 30–50 μm; And / or, the lateral spacing of the first groove microchannels is 5 to 10 mm; And / or, the beginning and end of all the first groove microchannels are connected sequentially and distributed in a vortex shape.
4. The silicon carbide composite seed crystal according to any one of claims 1-3, characterized in that, The silicon surface of the silicon carbide seed crystal is provided with a plurality of second groove microchannels, and the silicon surface of the transition layer is provided with a second protrusion microchannel corresponding to each of the second groove microchannels.
5. The silicon carbide composite seed crystal according to claim 4, characterized in that, The width of the second groove microchannel is 5–10 μm; And / or, the depth of the second groove microchannel is 30–50 μm; And / or, the lateral spacing of the second groove microchannels is 5-10 mm; And / or, the beginning and end of all the second groove microchannels are connected sequentially and distributed in a vortex shape.
6. The silicon carbide composite seed crystal according to claim 1, characterized in that, The heat dissipation substrate is a diamond substrate, and the transition layer is a silicon carbide transition layer; The surface of the diamond substrate is bonded to the carbon face of the silicon carbide transition layer, and the silicon face of the silicon carbide transition layer is bonded to the silicon face of the silicon carbide seed crystal; the crystal form of the silicon carbide material in the silicon carbide transition layer is different from the crystal form of the silicon carbide material in the silicon carbide seed crystal.
7. The silicon carbide composite seed crystal according to claim 1 or 6, characterized in that, The heat dissipation substrate is made of monocrystalline diamond or polycrystalline diamond; And / or, the thickness of the heat dissipation substrate is 300–500 μm; And / or, the thickness of the heat dissipation substrate is less than or equal to two-thirds of the thickness of the silicon carbide composite seed crystal, and the thickness of the heat dissipation substrate is greater than or equal to one-half the thickness of the silicon carbide composite seed crystal; And / or, the surface roughness of the heat dissipation substrate is less than a first preset roughness; wherein, the value of the first preset roughness ranges from 1 to 5 nm.
8. The silicon carbide composite seed crystal according to claim 6, characterized in that, The silicon carbide material in the silicon carbide transition layer has a crystal form of 3C, 4H, 6H or 15R. And / or, the thickness of the silicon carbide transition layer is 10–50 μm; And / or, the surface roughness of the silicon surface of the silicon carbide transition layer is less than a second preset roughness; wherein, the value of the second preset roughness ranges from 1 to 5 nm; And / or, the silicon carbide transition layer is formed by epitaxial growth or heterobonding.
9. The silicon carbide composite seed crystal according to claim 6, characterized in that, The silicon carbide seed crystal has a crystal form of 3C, 4H, 6H or 15R. And / or, the thickness of the silicon carbide seed crystal is 100-200 μm; And / or, the thickness of the silicon carbide seed crystal is less than one-third of the thickness of the silicon carbide composite seed crystal; And / or, the silicon carbide seed crystal is formed by epitaxial growth or heterobonding.
10. A silicon carbide seed crystal module, characterized in that, include: Silicon carbide seed crystal holder; Silicon carbide composite seed crystal as described in any one of claims 1-9; An adhesive layer is disposed between the silicon carbide seed crystal holder and the heat dissipation substrate in the silicon carbide composite seed crystal, for bonding the silicon carbide composite seed crystal to the silicon carbide seed crystal holder.