A porous material for silicon carbide crystal growth and its preparation method

Abstract

The present invention discloses a porous material for silicon carbide crystal growth and a preparation method thereof in the field of silicon carbide crystal growth. In the present invention, a nitrogen-containing polymer is prepared by using melamine and cyanuric chloride as polymer monomers, and tantalum chloride is used as a dopant, so that tantalum elements can be uniformly distributed in the polymer network. After sintering, a TaC / TaN-doped porous material is formed. The doping of tantalum and the formation of TaN / TaC can promote the uniform distribution of silicon carbide grains, prevent the formation of large grains, and thus obtain silicon carbide crystals with finer and uniform particle sizes. Due to the stability of tantalides, they can effectively promote the morphology control of silicon carbide crystals at high temperatures (such as controlling the aspect ratio of crystals).

Description

Technical Field

[0001] The present invention belongs to the technical field of silicon carbide crystal growth, and specifically refers to a porous material for silicon carbide crystal growth and a preparation method thereof. Background Art

[0002] Silicon carbide (SiC) is an important wide-bandgap semiconductor material with excellent electrical, thermal, and mechanical properties. Due to its high breakdown electric field strength, high-temperature stability, radiation resistance, and chemical stability, silicon carbide has a wide range of applications in high-power, high-frequency, high-temperature fields (such as power electronics, optoelectronics, sensors, LEDs, etc.). Common methods for growing silicon carbide crystals include physical vapor deposition (PVT), chemical vapor deposition (CVD), liquid phase epitaxial growth (LPE), etc. Among them, PVT is the most commonly used growth method. It generates silicon carbide through a gas-phase reaction at high temperature, where a carbon source and a silicon source react, and then deposits to form crystals on a suitable substrate. Its basic principle is to carry out a gas-phase reaction in a high-temperature furnace, where a carbon source (such as graphite or methane) and a silicon source (such as silane) react to generate SiC crystals. During the growth process, factors such as gas flow, temperature distribution, and the concentration of reaction gases have an important impact on the quality and growth rate of the crystals. Although the PVT method can obtain high-quality silicon carbide crystals at a relatively high growth temperature, the growth rate of the crystals is slow and defects such as dislocations are likely to occur, making it difficult to further improve the crystal quality; the chemical vapor deposition method is also commonly used for the growth of silicon carbide thin films and single crystals. This method decomposes a silicon source gas (such as silane, trichlorosilane, etc.) and a carbon source gas (such as methane) in a reaction chamber to generate SiC thin films or crystals. Compared with the PVT method, the CVD method can usually obtain good uniformity and a higher deposition rate at a lower temperature. The CVD technology has high requirements for process parameters (such as gas flow, temperature, pressure, etc.), so this method requires precise control; during the silicon carbide crystal growth process, the quality of the crystals is affected by various factors, among which crystal defects (such as dislocations, vacancies, impurities, etc.) are the main factors affecting the performance of silicon carbide devices. Especially at high temperatures, dislocations will increase the brittleness of the crystals and affect the stability of the devices. Therefore, reducing the defects generated during the growth process and improving the crystal quality have always been the focus of silicon carbide crystal growth research.

[0003] During the growth process of silicon carbide crystals, the choice of substrate plays an important role in the quality of the crystals. Traditionally, silicon carbide substrates are commonly used in the PVT method. However, due to the relatively large coefficient of thermal expansion of silicon carbide itself, thermal stress may occur during crystal growth, affecting the crystal quality. Therefore, researchers have explored the application of other substrate materials, such as quartz, molybdenum, ceramics, etc. In recent years, porous materials have been proposed as a method to optimize the growth quality of silicon carbide crystals. These porous materials can improve gas flow, provide a uniform temperature distribution, and reduce thermal stress, thereby optimizing the crystal growth conditions. Graphite, as a porous material, has good chemical stability and moderate thermal conductivity, so it is widely used in the growth process of silicon carbide crystals. However, the service life of graphite is short, and it is easily corroded and worn in a high-temperature environment, so it needs to be frequently replaced, which increases the cost of silicon carbide crystal growth. With the increasing requirements for cost and material properties, the application of graphite faces certain challenges. Summary of the Invention

[0004] In view of the above situation, to overcome the defects of the prior art, the present invention provides a porous material for the growth of silicon carbide crystals and a preparation method thereof. By using melamine and cyanuric chloride as polymer monomers to prepare a nitrogen-containing polymer, and using tantalum chloride as a dopant, the tantalum element can be uniformly distributed in the polymer network. After sintering, a TaC / TaN-doped porous material is formed. The doping of tantalum and the formation of TaN / TaC can promote the uniform distribution of silicon carbide grains, prevent the formation of large grains, and thus obtain silicon carbide crystals with finer and uniform particle sizes. Since tantalum compounds have high stability, they can effectively promote the growth morphology of silicon carbide crystals at high temperatures (such as controlling the aspect ratio of the crystals).

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: The present invention proposes a preparation method of a porous material for the growth of silicon carbide crystals, which specifically includes the following steps:

[0006] S1. Dissolve melamine in a DMF / absolute ethanol solution. After heating and stirring until dissolved, in a flowing nitrogen atmosphere, add a cyanuric chloride solution. Continuously stir to make the reaction system mix evenly, then raise the reaction temperature to 50 - 80 °C, stir and react for 6 - 12 h, add sodium carbonate as an acid-binding agent. After the reaction ends, wash, filter by suction, and dry to obtain a nitrogen-containing polymer;

[0007] Preferably, in step S1, the mass ratio between melamine and cyanuric chloride is 1.5 - 2.5:2;

[0008] Preferably, in step S1, in the DMF / absolute ethanol solution, the volume ratio between DMF and absolute ethanol is 1.5 - 2:1;

[0009] Preferably, in step S1, the mass concentration of melamine in the DMF / absolute ethanol solution is 60 - 80 mg / mL;

[0010] Preferably, in step S1, the cyanuric chloride solution is a solution prepared by dissolving cyanuric chloride in DMF, wherein the mass concentration of cyanuric chloride in DMF is 0.1 - 0.2 g / mL;

[0011] S2. Dissolve the nitrogen-containing polymer prepared in step S1 in the DMF / absolute ethanol solution, introduce flowing nitrogen, slowly add the tantalum chloride / absolute ethanol solution, stir evenly, then raise the reaction temperature to 40 - 60 °C, stir and react for 3 - 5 h, then perform reduced-pressure distillation, wash and dry to obtain the tantalum-doped polymer;

[0012] Preferably, in step S2, the mass concentration of the nitrogen-containing polymer in DMF / absolute ethanol is 40 - 60 mg / mL;

[0013] Preferably, in step S2, the added mass of tantalum chloride is 1% - 5% of the mass of the nitrogen-containing polymer;

[0014] Preferably, in step S2, in the tantalum chloride / absolute ethanol solution, the mass concentration of tantalum chloride in absolute ethanol is 0.05 - 0.06 g / mL;

[0015] S3. Transfer the tantalum-doped polymer prepared in step S2 to a high-temperature reaction kettle, under a nitrogen atmosphere, raise the reaction temperature to 300 - 400 °C for pre-sintering treatment, keep it for 1 - 2 h, then continue to raise the temperature to 1000 - 1400 °C, keep the temperature and sinter for 8 - 12 h, and then naturally cool to room temperature to obtain the porous material;

[0016] The present invention also provides a porous material for silicon carbide crystal growth prepared by the above method.

[0017] The beneficial effects achieved by the present invention are as follows:

[0018] The present invention provides a porous material for silicon carbide crystal growth and a preparation method thereof. A nitrogen-containing polymer is prepared using melamine and cyanuric chloride as polymer monomers, and tantalum chloride is used as a dopant to enable the uniform distribution of tantalum elements in the polymer network. After sintering, a TaC / TaN-doped porous material is formed. The doping of tantalum and the formation of TaN / TaC can promote the uniform distribution of silicon carbide grains, prevent the formation of large grains, and thus obtain silicon carbide crystals with finer and more uniform particle sizes. Due to the high stability of tantalum compounds, they can effectively promote the morphological control of silicon carbide crystals at high temperatures (such as controlling the aspect ratio of crystals); in the present invention, the polymer formed by the reaction of melamine and cyanuric chloride has a highly crosslinked triazine network structure. Due to the strong stability of this crosslinked structure, it can effectively embed tantalum elements (such as TaCl5) into the polymer stably in a coordination or ion exchange manner. In this way, tantalum elements can be uniformly dispersed in the polymer structure, avoiding the aggregation or non-uniform distribution of tantalum elements, thereby providing a stable doping source for the subsequent sintering process. Melamine contains multiple amino groups, and these amino groups can undergo coordination reactions with tantalum elements, enhancing the stability of tantalum elements and forming stable nitrides or carbides. The amino groups of melamine can also improve the reactivity of the polymer at high temperatures, providing support for the conversion of tantalum during the sintering process. Since the polymer formed by melamine and cyanuric chloride has good structure regulation ability, it can control the morphology, size, and distribution of tantalum elements during the sintering process, thereby affecting important properties such as the particle size, lattice structure, and conductivity of the finally formed tantalum nitride (TaN) and tantalum carbide (TaC). During the sintering process, due to the removal of organic substances (such as melamine and cyanuric chloride), the structure of the polymer changes to form a porous material. The formation of porosity helps to reduce the density of the material and can improve the conductivity, thermal conductivity, and other properties of TaC / TaN. The porous material prepared by the present invention has a porous structure, can provide nucleation sites, and helps the uniform distribution of crystals. Tantalum compounds (TaN and TaC) can catalyze the growth of silicon carbide, increase the reaction rate, lower the growth temperature, precisely control the concentration of nitrogen and carbon sources, optimize the crystal quality of silicon carbide, and improve the grain size and crystal morphology. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 XRD image of the porous material prepared in Example 1 of the present invention;

[0020] Figure 2 SEM image of the porous material prepared in Example 1 of the present invention;

[0021] Figure 3 Porosity result diagram of the porous materials prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention;

[0022] Figure 4 This is the thermal conductivity result graph of the porous materials prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention.

[0023] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. Detailed Embodiments

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] Unless otherwise defined, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the present invention. The preferred implementation methods and materials described herein are only for demonstration purposes, but cannot limit the content of this application.

[0026] The experimental methods in the following embodiments are all conventional methods unless otherwise specified; the test materials and test strains used in the following embodiments are all obtained from commercial channels unless otherwise specified.

[0027] Example 1

[0028] This example provides a preparation method for a porous material used for silicon carbide crystal growth, specifically including the following steps:

[0029] S1. Prepare a DMF / absolute ethanol solution by mixing DMF and absolute ethanol at a volume ratio of 1.5:1. Accurately weigh 1.5 g of melamine and dissolve it in 25 mL of the DMF / absolute ethanol solution. Raise the temperature to 50 °C, stir at a speed of 200 rpm until the melamine is completely dissolved, then introduce flowing nitrogen. Take 2.0 g of cyanuric chloride and dissolve it in 10 mL of DMF to obtain a cyanuric chloride solution. After adding it to the reaction system, keep the reaction temperature at 50 °C, add 10 mL of a 0.1 g / mL sodium carbonate / absolute ethanol solution, stir at a speed of 200 rpm for 8 h, and then end the reaction. After cooling, wash it three times repeatedly with deionized water, 0.05 M HCl aqueous solution, and absolute ethanol, then filter by suction, collect the solid, and vacuum dry it at 50 °C for 12 h to obtain a nitrogen-containing polymer:

[0030] S2. Prepare a DMF / absolute ethanol solution by mixing DMF and absolute ethanol at a ratio of 5:1. Accurately weigh 5.0 g of the nitrogen-containing polymer prepared in step S1 and dissolve it in 100 mL of the DMF / absolute ethanol solution. Pass a flowing nitrogen gas. Accurately weigh 0.5 g of tantalum chloride and dissolve it in 10 mL of absolute ethanol to obtain a tantalum chloride / absolute ethanol solution. Take 1 mL of the tantalum chloride / absolute ethanol solution and add it to the reaction system. Stir at a speed of 300 rpm. After raising the reaction temperature to 50 °C, continue to stir and react for 4 h. Then, distill off the excess solution under reduced pressure, wash with absolute ethanol to remove the excess tantalum chloride, and place it in a vacuum dryer at 50 °C for 12 h to obtain a tantalum-doped polymer;

[0031] S3. Transfer the tantalum-doped polymer prepared in step S2 to a high-temperature reaction kettle. Under a nitrogen atmosphere, raise the reaction temperature to 300 °C at a rate of 10 °C / min for pre-sintering treatment. After maintaining for 2 h, continue to raise the temperature to 1000 °C and maintain the temperature for sintering for 12 h. Then, naturally cool to room temperature to obtain a porous material.

[0032] This example also provides a porous material for silicon carbide crystal growth prepared by the above method.

[0033] Use an ADVANCE D8 X-ray diffractometer (X-ray diffraction, XRD) to analyze the sample phase. Figure 1 This is the XRD image of the porous material prepared in Example 1 of the present invention. As shown in the figure, the porous material prepared in Example 1 has diffraction peaks of TaC, TaN, CN, and C. The material contains TaC, TaN, and CN phases at the same time. In addition to the main peak of TaC, diffraction peaks of TaN should also be observed at positions such as 2θ≈36°, 42°, 61°, and 72°-79°. At the same time, if it contains g-C3N4 with a higher crystallinity, characteristic peaks may appear near 13° and 27°. If CN is in an amorphous or low-crystallinity state, a broad and weak diffuse peak appears in the 20°-30° region.

[0034] Use a JEOL FE6460 scanning electron microscope (scanning electron microscope, SEM) to observe the microscopic morphology of the sample. Figure 2 This is the SEM image of the porous material prepared in Example 1 of the present invention. As shown in the figure, the porous material prepared in Example 1 has a good pore structure, showing a highly interconnected pore network. The pore sizes are different. Some pores are in regular shapes, and some are more irregular, indicating that the porous material prepared in Example 1 forms uniformly distributed pores during the synthesis process, which helps to improve the diffusion and heat transfer performance of the reactants.

[0035] Example 2

[0036] This embodiment provides a method for preparing a porous material for silicon carbide crystal growth, which specifically includes the following steps:

[0037] S1. Prepare a DMF / absolute ethanol solution by mixing DMF and absolute ethanol at a volume ratio of 2:1. Accurately weigh 2.0 g of melamine and dissolve it in 25 mL of the DMF / absolute ethanol solution. Raise the temperature to 50 °C, stir at a speed of 200 rpm until the melamine is completely dissolved, then introduce flowing nitrogen. Weigh 2.0 g of cyanuric chloride and dissolve it in 15 mL of DMF to obtain a cyanuric chloride solution. After adding it to the reaction system, keep the reaction temperature at 80 °C, add 10 mL of a 0.1 g / mL sodium carbonate / absolute ethanol solution, stir at a speed of 200 rpm for 6 h. After the reaction ends, cool it, wash it three times repeatedly with deionized water, 0.05 M HCl aqueous solution and absolute ethanol, then perform suction filtration, collect the solid, and vacuum dry it at 50 °C for 12 h to obtain a nitrogen-containing polymer:

[0038] S2. Prepare a DMF / absolute ethanol solution by mixing DMF and absolute ethanol at a ratio of 5:1. Accurately weigh 5.0 g of the nitrogen-containing polymer prepared in step S1 and dissolve it in 100 mL of the DMF / absolute ethanol solution. Introduce flowing nitrogen. Accurately weigh 0.5 g of tantalum chloride and dissolve it in 10 mL of absolute ethanol to obtain a tantalum chloride / absolute ethanol solution. Take 1 mL of the tantalum chloride / absolute ethanol solution and add it to the reaction system, stir at a speed of 300 rpm, raise the reaction temperature to 50 °C, continue to stir and react for 4 h, then distill off the excess solution under reduced pressure, wash the reaction with absolute ethanol to remove the excess tantalum chloride, and vacuum dry it at 50 °C for 12 h to obtain a tantalum-doped polymer;

[0039] S3. Transfer the tantalum-doped polymer prepared in step S2 to a high-temperature reaction kettle. Under a nitrogen atmosphere, raise the reaction temperature to 350 °C at a rate of 10 °C / min for pre-sintering treatment. After maintaining for 2 h, continue to raise the temperature to 1200 °C, maintain the temperature and sinter for 8 h, and then naturally cool to room temperature to obtain a porous material.

[0040] This embodiment also provides a porous material for silicon carbide crystal growth prepared by the above method.

[0041] Example 3

[0042] This embodiment provides a method for preparing a porous material for silicon carbide crystal growth, which specifically includes the following steps:

[0043] S1. Prepare a DMF / ethanol solution by mixing DMF and anhydrous ethanol at a volume ratio of 1.5:1. Accurately weigh 2.5 g of melamine and dissolve it in 35 mL of the DMF / ethanol solution. Raise the temperature to 50 °C and stir at a speed of 200 rpm until the melamine is completely dissolved. Then, introduce flowing nitrogen. Dissolve 2.0 g of cyanuric chloride in 20 mL of DMF to obtain a cyanuric chloride solution. After adding it to the reaction system, maintain the reaction temperature at 70 °C. Add 10 mL of a 0.1 g / mL sodium carbonate / ethanol solution and stir at a speed of 200 rpm for 12 h. After the reaction is completed, cool it down. Wash it three times repeatedly with deionized water, 0.05 M HCl aqueous solution, and anhydrous ethanol, then perform suction filtration to collect the solid. After vacuum drying at 50 °C for 12 h, a nitrogen-containing polymer is obtained:

[0044] S2. Prepare a DMF / ethanol solution by mixing DMF and anhydrous ethanol at a ratio of 5:1. Accurately weigh 5.0 g of the nitrogen-containing polymer prepared in step S1 and dissolve it in 100 mL of the DMF / ethanol solution. Introduce flowing nitrogen. Accurately weigh 0.5 g of tantalum chloride and dissolve it in 10 mL of anhydrous ethanol to obtain a tantalum chloride / ethanol solution. Take 1 mL of the tantalum chloride / ethanol solution and add it to the reaction system. Stir at a speed of 300 rpm. After raising the reaction temperature to 50 °C, continue to stir and react for 4 h. Then, distill off the excess solution under reduced pressure. Wash the reaction with anhydrous ethanol to remove the excess tantalum chloride. After vacuum drying at 50 °C for 12 h, a tantalum-doped polymer is obtained;

[0045] S3. Transfer the tantalum-doped polymer prepared in step S2 to a high-temperature reaction kettle. Under a nitrogen atmosphere, raise the reaction temperature to 400 °C at a rate of 10 °C / min for pre-sintering treatment. After maintaining for 1 h, continue to raise the temperature to 1400 °C and maintain the temperature for sintering for 10 h. After naturally cooling to room temperature, a porous material is obtained.

[0046] This example also provides a porous material for silicon carbide crystal growth prepared by the above method.

[0047] Comparative Example 1

[0048] This comparative example provides a porous material and its preparation method. The difference from Example 1 is only that step S2 is not included in the preparation method of the porous material, and the other components, component contents, and preparation methods are the same as those in Example 1.

[0049] Comparative Example 2

[0050] This comparative example provides a porous material and a preparation method thereof. The difference from Example 1 is only that steps S1 and S2 of the preparation method of the porous material are modified as follows: DMF and absolute ethanol are prepared into a DMF / absolute ethanol solution according to a volume ratio of 1.5:1. 1.5 g of melamine is accurately weighed and dissolved in 25 mL of the DMF / absolute ethanol solution. The temperature is raised to 50 °C, and after stirring at a speed of 200 rpm until the melamine is completely dissolved, flowing nitrogen is introduced. 0.5 g of tantalum chloride is dissolved in 10 mL of absolute ethanol to obtain a tantalum chloride / absolute ethanol solution. 1 mL of the tantalum chloride / absolute ethanol solution is added to the reaction system, and the reaction temperature is maintained at 50 °C. 10 mL of a 0.1 g / mL sodium carbonate / absolute ethanol solution is added, and after stirring at a speed of 200 rpm for 8 h, the reaction ends. After cooling, it is washed three times repeatedly with deionized water, 0.05 M HCl aqueous solution, and absolute ethanol, then filtered by suction, the solid is collected, and after vacuum drying at 50 °C for 12 h, a tantalum-doped polymer is obtained; step S3 is the same as that in Example 1, and a porous material is prepared.

[0051] Experimental Example 1

[0052] The porosity refers to the percentage of the pore volume in a bulk material to the total volume of the material in its natural state. The porosity or density of a material directly reflects its degree of compactness. A high porosity of a material indicates a low degree of compactness. The porosities of the porous material samples prepared in Examples 1-3 and Comparative Examples 1-2 were measured using a true density meter of the Ultrapyc 5000 model from Anton Paar. The temperature was set at 25 °C, and a nitrogen atmosphere was used. Five data were measured for each sample and averaged.

[0053] Figure 3 The following is a graph showing the porosity results of the porous materials prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention. As shown in the figure, the porosities of the porous materials prepared in Examples 1-3 are between 50% and 55%, while the porosity of the porous material prepared in Comparative Example 1 is 34.2%, and the porosity of the porous material prepared in Comparative Example 2 is 87.3%. The pores of the porous materials prepared in Examples 1-3 are uniform and the porosity is moderate.

[0054] Experimental Example 2

[0055] In this experimental example, the thermal conductivity of the porous materials prepared in Examples 1-3 and Comparative Examples 1-3 was analyzed. When there is no relative displacement between different parts of an object, the heat energy transfer generated by the thermal motion of microscopic particles such as molecules, atoms, and free electrons is called heat conduction. The laser flash method is a commonly used method for measuring the thermal conductivity of materials. The basic principle of measurement is as follows: at a certain set temperature, a laser source instantaneously emits a light pulse, which uniformly irradiates the lower surface of the sample, causing the temperature of its surface layer to instantaneously rise after absorbing the light energy, and this acts as the hot end to transfer the energy to the upper surface in a one-dimensional heat conduction manner. An infrared detector is used to continuously measure the corresponding temperature rise process at the center of the upper surface. The thermal conductivity and thermal diffusivity of the specimens were analyzed and tested using an LFA467 flash method thermal conductivity analyzer produced by Netzsch GmbH. The specimens were cut into squares with a size of 10 mm × 10 mm, the temperature was set at 25 °C, and the measurement was carried out 3 times in a nitrogen atmosphere.

[0056] Figure 4 The following is a graph showing the results of the thermal conductivity of the porous materials prepared in Examples 1-3 and Comparative Examples 1-2 of the present invention. As shown in the figure, the thermal conductivity of the porous materials prepared in Examples 1-3 of the present invention is significantly higher than that of Comparative Examples 1-2. Since the pore distribution in Comparative Example 1 is uneven, the thermal conductivity is poor. In Comparative Example 2, due to the excessive porosity, it introduces obstacles to the heat conduction in the porous material, resulting in a significant decrease in the thermal conductivity.

[0057] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

[0058] The above description of the present invention and its embodiments is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual application is not limited thereto. Generally speaking, if those of ordinary skill in the art are inspired by it and, without departing from the purpose of the present invention, design similar ways and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.

Claims

1. A preparation method of a porous material for silicon carbide crystal growth, characterized in that: Specifically, it includes the following steps: S1. Dissolve melamine in the DMF / absolute ethanol solution. After heating and stirring until it is dissolved, under a flowing nitrogen atmosphere, add the cyanuric chloride solution according to the mass ratio of melamine to cyanuric chloride being 1.5 - 2.5:

2. After continuously stirring to make the reaction system mix evenly, raise the reaction temperature to 50 - 80 °C, stir and react for 6 - 12 h, then add sodium carbonate as an acid-binding agent. After the reaction ends, wash, filter by suction, and dry to obtain a nitrogen-containing polymer; S2. Dissolve the nitrogen-containing polymer prepared in step S1 in the DMF / absolute ethanol solution, introduce flowing nitrogen, and slowly add the tantalum chloride / absolute ethanol solution according to the added mass of tantalum chloride being 1% - 5% of the mass of the nitrogen-containing polymer. After stirring evenly, raise the reaction temperature to 40 - 60 °C, stir and react for 3 - 5 h, then carry out vacuum distillation, wash, and dry to obtain a tantalum-doped polymer; S3. Transfer the tantalum-doped polymer prepared in step S2 to a high-temperature reaction kettle. Under a nitrogen atmosphere, raise the reaction temperature to 300 - 400 °C for pre-sintering treatment. After maintaining for 1 - 2 h, continue to raise the temperature to 1000 - 1400 °C, maintain the temperature and sinter for 8 - 12 h, and then naturally cool to room temperature to obtain a porous material.

2. The preparation method of a porous material for silicon carbide crystal growth according to claim 1, wherein: In step S1, in the DMF / absolute ethanol solution, the volume ratio of DMF to absolute ethanol is 1.5 - 2:

1.

3. The preparation method of a porous material for silicon carbide crystal growth according to claim 2, wherein: In step S1, the mass concentration of melamine in the DMF / absolute ethanol solution is 60 - 80 mg / mL.

4. The preparation method of a porous material for silicon carbide crystal growth according to claim 3, characterized in that: In step S1, the cyanuric chloride solution is a solution of cyanuric chloride dissolved in DMF, where the mass concentration of cyanuric chloride in DMF is 0.1 - 0.2 g / mL.

5. The preparation method of a porous material for silicon carbide crystal growth according to claim 4, characterized in that: In step S2, the mass concentration of the nitrogen-containing polymer in DMF / absolute ethanol is 40 - 60 mg / mL.

6. The preparation method of a porous material for silicon carbide crystal growth according to claim 5, characterized in that: In step S2, in the tantalum chloride / absolute ethanol solution, the mass concentration of tantalum chloride in absolute ethanol is 0.05 - 0.06 g / mL.

7. A porous material for silicon carbide crystal growth, characterized in that, The porous material is made according to the preparation method described in any one of claims 1 - 6.

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