Tantalum carbide porous ceramic and preparation method thereof, high-performance wafer material and semiconductor material

Abstract

The invention discloses tantalum carbide porous ceramic and a preparation method thereof, a high-performance wafer material and a semiconductor material, solves the problem of ultrahigh-temperature sintering of tantalum carbide, effectively controls the pore structure and strength, and can be used as a semiconductor raw material. Comprising the following steps: taking a tantalum source in absolute ethyl alcohol according to a weight ratio of the tantalum source to the absolute ethyl alcohol of 1: 1, and stirring to form a transparent solution, so as to obtain a tantalum source solution; glucose is taken and added into the tantalum source solution, the weight ratio of the tantalum source solution to the glucose is (30-43): 9, stirring is performed to form a transparent solution, and a solution finished product is obtained; slowly dropwise adding dilute nitric acid into the solution finished product, stirring to a stable sol state, and stopping stirring to obtain sol; introducing the sol into a polytetrafluoroethylene mold, and placing the mold in a constant-temperature and constant-humidity box to avoid vibration or stirring; taking out the gel from the mold, putting the gel into a vacuum drying oven, and pouring the gel onto a graphite plate after drying is completed; and putting the gel into a high-temperature furnace, and carrying out high-temperature carbonization treatment to obtain the tantalum carbide porous ceramic.

Description

Technical Field

[0001] This invention relates to the field of semiconductors, and more particularly to a method for preparing porous tantalum carbide ceramics. Background Technology

[0002] Tantalum carbide ceramics are one of the most advanced ceramic varieties in modern times. They have a very stable structure, high melting point, high hardness, and good chemical stability, and can remain stable even in high-temperature or high-energy deposition environments.

[0003] High-performance wafer materials are mainly high-purity single-crystal silicon, and also include silicon carbide and gallium nitride.

[0004] Tantalum carbide ceramic is an important substrate material for synthesizing high-performance wafer materials, which are key raw materials in semiconductor technology and belong to the third generation of semiconductor materials. With the demands and development of modern semiconductor technology and in response to international pressure, the optimization and research of these materials is urgently needed.

[0005] In modern applications, the following are common scenarios for the fabrication of high-performance wafer materials:

[0006] Silicon carbide (SiC) crystals are grown using the physical vapor transport (PVT) method. Typically, this involves heating silicon carbide powder in a sealed growth chamber at a temperature of 2300°C, near vacuum, and low pressure via induction heating. This sublimation produces gases such as Si, Si₂C, and SiC₂, which then act as a reaction source for SiC single crystals through a solid-gas reaction. A SiC seed crystal is placed at the upper end of the growth chamber. Driven by the supersaturation of the gas phase components, the gases are transported to the SiC seed crystal, where atomic deposition occurs on the seed crystal surface, ultimately growing into a SiC single crystal.

[0007] The disadvantages are that this method is difficult to control, has a long growth cycle, and even slight adjustments or drifts in the furnace thermal field can lead to changes in microtubes, inclusions, or an increase in various defects in the crystal.

[0008] Furthermore, existing technologies using graphite-based thermal field materials to grow silicon carbide (SiC) crystals are prone to oxidation and corrosion by molten metal at high temperatures. Although adding tantalum carbide coatings can improve performance, current tantalum carbide coating preparation technologies have several shortcomings. For example, the conventional chemical vapor deposition (CVD) method results in a slow deposition rate due to the high temperature during deposition, especially for large-area coatings, which require even longer preparation times. The coating has poor adhesion and density, and the large difference in expansion coefficients can easily generate thermal stress, leading to reduced adhesion during high-temperature service. Gas distribution and flow field are difficult to control, affecting the uneven coating deposition thickness and causing problems such as carbon deficiency in the compound or enrichment of free carbon, thus affecting coating quality.

[0009] Based on this, those skilled in the art are also actively researching different methods to improve the quality of silicon carbide (SiC) crystals grown using tantalum carbide ceramic as a substrate material. Summary of the Invention

[0010] This invention discloses a porous tantalum carbide ceramic and its preparation method, a high-performance wafer material, and a semiconductor material. It solves the problem of ultra-high temperature sintering of tantalum carbide, effectively controls the pore structure and strength, and can be used as a semiconductor raw material.

[0011] To address the above problems, this invention provides a method for preparing porous tantalum carbide ceramics, comprising the following steps:

[0012] (A) Take the following raw materials: tantalum source, glucose, anhydrous ethanol with a purity of ≥99.5%, and dilute nitric acid with a mass fraction of 5%;

[0013] (B) Take tantalum source in anhydrous ethanol at a weight ratio of tantalum source: anhydrous ethanol = 1:1, stir with a magnetic stirrer at a speed of 400±40 rpm for 30 minutes to form a transparent solution, and obtain the tantalum source solution.

[0014] (C) Add glucose to the tantalum source solution at a weight ratio of tantalum source solution: glucose = 30-43:9, and continue stirring at 400±40 rpm for 10 minutes to form a transparent solution and obtain the solution product.

[0015] (D) Slowly add dilute nitric acid dropwise to the solution product, and stir at 400 rpm until the pH value falls between 5.5 and 6.5. Then, change the stirring speed to 200 rpm and keep stirring for 30 minutes until a stable sol state is reached. Stop stirring to obtain the sol.

[0016] (E) Pour the sol into the polytetrafluoroethylene mold, and then place the mold in a constant temperature and humidity chamber and let it stand for 24-36 hours at a temperature of 60±3℃, avoiding vibration.

[0017] (F) Remove the gel from the mold and place it in a vacuum drying oven. Keep it at a temperature of 80±5℃ and a vacuum of -80KPa for 24-36 hours. After drying, pour the gel onto a graphite plate for later use.

[0018] (G) Take the gel into a high-temperature furnace and, under the protection of an inert atmosphere, perform high-temperature carbonization treatment at a temperature of 1400-1800℃ for 12-24 hours to obtain tantalum carbide porous ceramic.

[0019] Preferably, the method further includes the step of:

[0020] (H) Take tantalum carbide porous ceramic into a graphite mold, then place the graphite mold in the chamber of a spark plasma sintering furnace, press the upper and lower electrodes onto the upper and lower surfaces of the graphite mold respectively, close the chamber, vacuum 4-6 Pa, purge inert gas to 0.1-0.2 MPa, start the power supply, the heating rate is 100℃ / min, heat to 2000-2050℃, hold for 15-30 minutes, and then turn off the power supply and let it cool.

[0021] (I) After cooling to 100°C, slowly fill with air until it is equal to atmospheric pressure, remove the graphite mold, and then remove the tantalum carbide porous ceramic structure to obtain the sintered tantalum carbide porous ceramic.

[0022] Preferably, the tantalum source is pentaethoxytantalum (Ta(OC2H5)5) with a purity ≥99.9%.

[0023] Preferably, the material of the graphite mold in step (H) is: graphite purity ≥ 99.9%, compressive strength 100~150MPa, resistivity 7-8μΩ·m, and melting point ≥ 3850℃.

[0024] Preferably, the graphite mold described in step (H) has the following structure: a graphite base, a graphite cover plate, and a cavity.

[0025] The graphite base has a concave structure with a cavity in the middle;

[0026] The graphite cover plate is placed on top of the graphite base and can be movably sealed.

[0027] The chamber is used to place the tantalum carbide porous ceramic, and the top and four sides of the tantalum carbide porous ceramic maintain an air gap of 2-3 mm with the interior of the graphite base.

[0028] Preferably, the method further includes the step of:

[0029] (J) Precision grinding was used to obtain polished tantalum carbide porous ceramic.

[0030] Preferably, the sintered tantalum carbide porous ceramic has a volume porosity of 35-55%, a pore size that can be controlled between 30-100 μm, and a bending strength of ≥20 MPa.

[0031] Preferably, the electroplasma sintering furnace has an output voltage of 5V, a pulse current of 0-50kA, a current frequency of 0-5000Hz, a maximum power of 300KW, and is in pressureless sintering mode.

[0032] A porous tantalum carbide ceramic is also provided, which is prepared by any of the above-described methods for preparing porous tantalum carbide ceramic.

[0033] Another high-performance wafer material is provided, which includes tantalum carbide porous ceramic prepared by any of the above as a substrate material.

[0034] Another semiconductor material is provided, including the high-performance wafer material prepared as described above.

[0035] The present invention provides a porous tantalum carbide ceramic and its preparation method, which can be used as a substrate material for preparing high-performance wafer materials for semiconductors. The required sintering temperature is much lower than the melting point of tantalum carbide ceramic (3730-3830℃) and also much lower than the sintering temperature of traditional curing method (2100-2300℃), which can significantly shorten the sintering time and reduce energy consumption.

[0036] Glucose was used as a carbon source. During the stirring process, its small molecular structure was easily decomposed at low temperature, generating more gas. This resulted in a solution with small and abundant pores. Moreover, the stirring process was not pressurized, resulting in high pore connectivity and uniform pores. By controlling the weight ratio, the pore structure could be made at the nanometer to micrometer scale.

[0037] Therefore, the preparation process of tantalum carbide ceramic of the present invention is relatively simple. Semiconductors prepared using this porous tantalum carbide ceramic can have high temperature resistance, excellent chemical stability, increased surface area due to pores, and good thermal conductivity. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of a graphite mold used in a method for preparing porous tantalum carbide ceramics according to the present invention.

[0039] The markings in the diagram are as follows: graphite base 1, graphite cover plate 2, chamber 3, air gap 4. Detailed Implementation

[0040] This invention discloses a porous tantalum carbide ceramic and its preparation method, a high-performance wafer material, and a semiconductor material. It solves the problem of ultra-high temperature sintering of tantalum carbide, effectively controls the pore structure and strength, and can be used as a semiconductor raw material.

[0041] This invention discloses a method for preparing porous tantalum carbide ceramics, comprising the following steps:

[0042] (A) Take the following raw materials: tantalum source, glucose, anhydrous ethanol with a purity of ≥99.5%, and dilute nitric acid with a mass fraction of 5%;

[0043] The tantalum source is tantalum pentaethoxy (Ta(OC2H5)5) with a purity ≥99.9%;

[0044] (B) Take tantalum source in anhydrous ethanol at a weight ratio of tantalum source: anhydrous ethanol = 1:1, stir with a magnetic stirrer at a speed of 400±40 rpm for 30 minutes to form a transparent solution, and obtain the tantalum source solution.

[0045] (C) Add glucose to the tantalum source solution at a weight ratio of tantalum source solution: glucose = 30-43:9, and continue stirring at 400±40 rpm for 10 minutes to form a transparent solution and obtain the solution product.

[0046] (D) Slowly add dilute nitric acid dropwise to the solution product, and stir at 400 rpm until the pH value falls between 5.5 and 6.5. Then, change the stirring speed to 200 rpm and keep stirring for 30 minutes until a stable sol state is reached. Stop stirring to obtain the sol.

[0047] (E) Pour the sol into the polytetrafluoroethylene mold, and then place the mold in a constant temperature and humidity chamber and let it stand for 24-36 hours at a temperature of 60±3℃, avoiding vibration.

[0048] (F) Remove the gel from the mold and place it in a vacuum drying oven. Keep it at a temperature of 80±5℃ and a vacuum of -80KPa for 24-36 hours. After drying, pour the gel onto a graphite plate for later use.

[0049] (G) Take the gel into a high-temperature furnace and, under the protection of an inert atmosphere, perform high-temperature carbonization treatment at a temperature of 1400-1800℃ for 12-24 hours to obtain tantalum carbide porous ceramic.

[0050] (H) Take tantalum carbide porous ceramic into a graphite mold, then place the graphite mold in the chamber of a spark plasma sintering furnace, press the upper and lower electrodes onto the upper and lower surfaces of the graphite mold respectively, close the chamber, vacuum 4-6 Pa, purge inert gas to 0.1-0.2 MPa, start the power supply, the heating rate is 100℃ / min, heat to 2000-2050℃, hold for 15-30 minutes, and then turn off the power supply and let it cool.

[0051] The graphite mold in step (H) is made of graphite with a purity of ≥99.9%, a compressive strength of 100-150 MPa, a resistivity of 7-8 μΩ·m, and a melting point of ≥3850℃.

[0052] The graphite mold has the following structure: it is provided with a graphite base, a graphite cover plate and a cavity;

[0053] The graphite base has a concave structure with a cavity in the middle;

[0054] The graphite cover plate is placed on top of the graphite base and can be movably sealed.

[0055] The chamber is used to place the tantalum carbide porous ceramic, and the top and four sides of the tantalum carbide porous ceramic maintain an air gap of 2-3 mm with the interior of the graphite base.

[0056] The electroplasma sintering furnace has an output voltage of 5V, a pulse current of 0-50kA, a current frequency of 0-5000Hz, a maximum power of 300KW, and is a pressureless sintering mode.

[0057] (I) After cooling to 100°C, slowly fill with air until it is equal to atmospheric pressure, remove the graphite mold, and then remove the tantalum carbide porous ceramic structure to obtain the sintered tantalum carbide porous ceramic.

[0058] (J) Precision grinding was used to obtain polished tantalum carbide porous ceramic.

[0059] The sintered tantalum carbide porous ceramic has a volume porosity of 35-55%, a pore size that can be controlled between 30-100μm, and a bending strength of ≥20MPa.

[0060] This step (H)(I) is to optimize uniformity.

[0061] A porous tantalum carbide ceramic is also provided, which is prepared by any of the above-described methods for preparing porous tantalum carbide ceramic.

[0062] Another high-performance wafer material is provided, which includes tantalum carbide porous ceramic prepared by any of the above as a substrate material.

[0063] Another semiconductor material is provided, including the high-performance wafer material prepared as described above.

[0064] This porous tantalum carbide ceramic is also known as the tantalum carbide (TaC) precursor.

[0065] This invention uses tantalum pentaethoxy, glucose, anhydrous ethanol, and dilute nitric acid as raw materials. Through high-speed stirring, a molecular-level reaction is achieved, ensuring that tantalum and carbon elements are uniformly distributed at the nanoscale. This effectively avoids potential component segregation problems in subsequent processes, guaranteeing high purity and consistency. Furthermore, if conventional methods are used to synthesize tantalum carbide, it can lead to agglomeration or uneven dispersion of tantalum and carbon powders, resulting in a significant lack of uniformity.

[0066] During the decomposition process, glucose forms a porous structure ranging from nanometers to micrometers, which is uniformly distributed under high-speed stirring. In other words, glucose forms a uniform, extremely small particle size framework for the synthesized product. After processing in step (H), glucose molecules form a gaseous phase or residual carbon framework, which determines the formation and uniform distribution of the microstructure of the pores.

[0067] Step (H) only requires sintering at 2000-2050℃, which is fast and dense, much lower than the 2100-2300℃ required by the traditional solid-state method, thus significantly shortening the sintering time and reducing energy consumption.

[0068] However, by using the structure and placement method of the graphite mold and a plasma sintering furnace, the high temperature and high energy environment generated by the plasma discharge during the sintering process can rapidly activate the surface of the powder particles, promote the material transport and diffusion between particles, accelerate the formation and growth of the sintering neck, and thus complete the sintering quickly at a relatively low temperature.

[0069] Specifically, within the structure of this tantalum carbide porous ceramic, the gaps at grain boundaries and particle contact surfaces are small, resulting in a significantly lower plasma breakdown barrier than the internal porous structure, thus preferentially generating discharge current. Conversely, the larger distances within the pores lead to a higher plasma breakdown barrier, resulting in a relatively smaller discharge current. The current generated by plasma discharge forms a non-uniform distribution within the ceramic preform, which can then lead to current enrichment on the tantalum carbide porous ceramic, improving the utilization rate of the plasma current and avoiding the high power requirements of the plasma generator due to the high temperatures required for sintering of tantalum carbide porous ceramics, thereby reducing equipment investment costs.

[0070] Furthermore, the preparation method adopted in this application significantly shortens the sintering time compared to existing technologies. Therefore, the crystal growth time is shorter and the crystals are less likely to grow larger during the sintering process, resulting in a fine and uniform crystal structure. The small crystal size results in a large surface area, which effectively improves various properties, such as mechanical properties, and is also more conducive to improving the physical properties of the same product. Therefore, it has excellent density and uniformity, reducing the problems of uneven distribution of internal defects and pores.

[0071] Dilute nitric acid accelerates the hydrolysis and condensation reaction of tantalum pentaethoxy, regulates the formation rate of the sol and stabilizes its structure, and also adjusts the pH value. The amount of glucose used is also a key factor in controlling porosity.

[0072] Following the steps described above, the sol obtained in steps (D) and (E) should form a three-dimensional network structure. The structure of the polytetrafluoroethylene mold can be determined based on the desired shape, size, and shrinkage rate of the finished product.

[0073] The inert atmosphere uses Ar inert gas with a purity of ≥99.99%.

[0074] In step (H) temperature control of 2000-2050℃, when the finished product requires large-sized micropores, a higher temperature is selected for temperature adaptation; when the finished product requires small-sized micropores, the temperature can be reduced and a longer heat preservation time can be selected.

[0075] The porous tantalum carbide ceramics prepared by the above method have the following advantages: (1) High temperature resistance, with a melting point of up to 3880℃. In the high-temperature environment of single crystal growth, it can maintain stable physical and chemical properties and will not melt, deform or react with the grown single crystal material due to high temperature, thus providing a stable support environment for single crystal growth. (2) Good chemical stability. It has excellent chemical stability and is not easily corroded by various chemical substances during single crystal growth. Whether in a gas phase growth environment containing various chemical gases or in a solution growth environment with certain chemical activity, the porous tantalum carbide ceramics can maintain its own chemical integrity, avoid contamination or interference to single crystal growth, and help to obtain high-purity single crystals. (3) Advantages of porous structure. Its porous structure provides unique conditions for single crystal growth: on the one hand, the porous structure can increase the specific surface area, which is conducive to the adsorption and diffusion of substances during single crystal growth, providing more active sites for single crystal nucleation and growth, and promoting uniform growth of single crystals; on the other hand, the pores can accommodate the stress during the growth process, alleviate the stress concentration problem caused by factors such as the difference in thermal expansion coefficient, reduce defects and dislocations in single crystals, and improve the quality of single crystals. (4) Good thermal conductivity. It can effectively conduct heat during single crystal growth, making the temperature distribution in the growth environment more uniform. This helps to control the temperature gradient of single crystal growth, avoid problems such as uneven growth and increased defects caused by excessively high or low local temperatures, and is conducive to obtaining high-quality single crystal materials.

[0076] Example 1

[0077] A method for preparing porous tantalum carbide ceramics includes the following steps:

[0078] (A1) Take the following raw materials: tantalum pentaethoxylate (Ta(OC2H5)5) with a purity ≥99.9%, glucose, anhydrous ethanol with a purity ≥99.5%, and dilute nitric acid with a mass fraction of 5%.

[0079] (B1) Take pentaethoxytantalum in anhydrous ethanol at a weight ratio of pentaethoxytantalum:anhydrous ethanol = 1:1. Stir with a magnetic stirrer at a speed of 400±40 rpm for 30 minutes to form a transparent solution and obtain the tantalum source solution.

[0080] (C1) Add glucose to the tantalum source solution at a weight ratio of tantalum source solution: glucose = 30-43:9, and continue stirring at 400±40 rpm for 10 minutes to form a transparent solution and obtain the solution product.

[0081] (D1) Slowly add dilute nitric acid dropwise to the solution product and stir at 400 rpm until the pH value falls between 5.5 and 6.5. Then, change the stirring speed to 200 rpm and keep stirring for 30 minutes until a stable sol state is reached. Stop stirring to obtain the sol.

[0082] (E1) Pour the sol into the polytetrafluoroethylene mold, then place the mold in a constant temperature and humidity chamber and let it stand for 24-36 hours at a temperature of 60±3℃, avoiding vibration;

[0083] (F1) Remove the gel from the mold and place it in a vacuum drying oven. Keep it at a temperature of 80±5℃ and a vacuum of -80KPa for 24-36 hours. After drying, pour the gel onto a graphite plate for later use.

[0084] (G1) Take the gel into a high-temperature furnace and, under the protection of an inert atmosphere, perform high-temperature carbonization treatment at a temperature of 1400-1800℃ for 12-24 hours to obtain tantalum carbide porous ceramic.

[0085] (H1) Take tantalum carbide porous ceramic into a graphite mold, then place the graphite mold in the chamber of a spark plasma sintering furnace, press the upper and lower electrodes onto the upper and lower surfaces of the graphite mold respectively, close the chamber, vacuum 4-6 Pa, purge inert gas to 0.1-0.2 MPa, start the power supply, the heating rate is 100℃ / min, heat to 2000-2050℃, hold for 15-30 minutes, and then turn off the power supply and let it cool.

[0086] The graphite mold in step (H) is made of graphite with a purity of ≥99.9%, a compressive strength of 100-150 MPa, a resistivity of 7-8 μΩ·m, and a melting point of ≥3850℃.

[0087] The graphite mold has the following structure: it is provided with a graphite base, a graphite cover plate and a cavity;

[0088] The graphite base has a concave structure with a cavity in the middle;

[0089] The graphite cover plate is placed on top of the graphite base and can be movably sealed.

[0090] The chamber is used to place the tantalum carbide porous ceramic, and the top and four sides of the tantalum carbide porous ceramic maintain an air gap of 2-3 mm with the interior of the graphite base.

[0091] The electroplasma sintering furnace has an output voltage of 5V, a pulse current of 0-50kA, a current frequency of 0-5000Hz, a maximum power of 300KW, and is a pressureless sintering mode.

[0092] (I1) After cooling to 100°C, slowly fill with air until it is equal to atmospheric pressure. Take out the graphite mold, then take out the tantalum carbide porous ceramic structure to obtain the sintered tantalum carbide porous ceramic. Its volume porosity is 35-55%, the pore size can be controlled between 30-100μm, and the bending strength can be ≥20MPa.

[0093] (J1) Precision grinding is used to obtain polished tantalum carbide porous ceramic.

[0094] A porous tantalum carbide ceramic is also provided, which is prepared by any of the above-described methods for preparing porous tantalum carbide ceramic.

[0095] Another high-performance wafer material is provided, which includes tantalum carbide porous ceramic prepared by any of the above as a substrate material.

[0096] Another semiconductor material is provided, including the high-performance wafer material prepared as described above.

[0097] Example 2

[0098] Preparation of 8-inch high-performance wafer material silicon carbide wafer deposition substrate-tantalum carbide ceramic.

[0099] The small area of ​​the silicon carbide wafer required for an 8-inch wafer necessitates the deposition of tantalum carbide porous ceramic substrates with relatively low porosity to control the number of nuclei and relatively small pore diameters to control the amount of transported gas phase, thereby reducing deposition defects.

[0100] (A2) Take pentaethoxytantalum (which can be purchased from Sigma-Aldrich (Shanghai)), glucose (molecular weight 180.16, analytical grade, which can be purchased from Thermo Fisher Scientific (China)), anhydrous ethanol (purity ≥99.5%), and 5% dilute nitric acid.

[0101] (B2) Dissolve tantalum pentaethoxy in anhydrous ethanol at a weight ratio of tantalum pentaethoxy (Ta(OC2H5)5): anhydrous ethanol = 1:1. Then, stir with a magnetic stirrer at 400±40 rpm for 30 minutes to form a clear solution. Next, add glucose solution at a weight ratio of tantalum pentaethoxy in anhydrous ethanol to glucose = 19:4, and continue stirring at 400±40 rpm for 10 minutes to ensure complete dissolution and form a clear solution.

[0102] (C2) Slowly add dilute nitric acid dropwise to the above transparent solution using a dropper to allow for complete hydrolysis and condensation reactions. Adjust the pH of the solution to a neutral or slightly acidic range of 5.5–6.5. Stirring should be maintained throughout the pH adjustment process. Before the pH reaches 5.5–6.5, stir at a high speed of 400±40 rpm. After the pH reaches 5.5–6.5, reduce the stirring speed to 200±20 rpm and continue stirring for 30 minutes. Stop stirring once the solution gradually forms a homogeneous and stable sol. At this point, a sol with a three-dimensional network structure should be obtained.

[0103] (D2) Pour the sol into a polytetrafluoroethylene mold, then place the mold containing the sol into a constant temperature and humidity chamber and let it stand at 60±3℃ for 24-36 hours to allow it to fully gel. At this point, a sol with a three-dimensional network structure should be obtained.

[0104] (E2) Remove the gel from the mold and place it in a vacuum drying oven at 80±5℃ with a vacuum of -80KPa for 24-36 hours to remove the ethanol solvent and trace amounts of residual moisture. After drying, pour the dried gel product out of the polytetrafluoroethylene mold and place it on a graphite substrate (graphite plate).

[0105] (F2) The dried gel product is placed in a high-temperature heat treatment furnace and subjected to high-temperature carbonization under an inert Ar atmosphere (purity ≥99.99%). The carbonization temperature is 1450±20℃, the holding time is 12±1 hours, and Ar protective gas is circulated throughout the process.

[0106] (G2) The finished product is transferred to a graphite mold. The graphite purity is ≥99.9%, compressive strength: 100~150MPa, resistivity: 7-8μΩ·m, and melting point ≥3850℃. It is placed in the chamber of a spark plasma sintering furnace. The vacuum pump is turned on to evacuate to 4-6Pa, and argon gas is introduced to 0.1-0.2MPa. The pulse power supply of the plasma sintering equipment is started, and a pulse current is applied, with the heating rate controlled at 100℃ / min. The sintering temperature is 2000-2050℃, and the temperature is held for 15 minutes. Then, the plasma pulse current is turned off, allowing the graphite mold to cool with the furnace in the argon atmosphere.

[0107] (H2) After the finished product cools to 100℃, open the valve and slowly fill it with air until it reaches the same pressure as atmospheric pressure. Open the furnace door, remove the graphite mold, and then remove the sintered tantalum carbide porous ceramic sintered body. At this point, the volume porosity of the tantalum carbide porous ceramic sintered body should be 40±3%, the pore size should be 30-70μm, and the overall bending strength should be ≥22MPa.

[0108] (I2) Grinding process to obtain the final product - tantalum carbide porous ceramic.

[0109] Example 3

[0110] Preparation of 16-inch high-performance wafer material silicon carbide wafer deposition substrate-tantalum carbide ceramic.

[0111] The large area of ​​silicon carbide wafers required for 16-inch wafers necessitates the deposition of porous tantalum carbide ceramic substrates with relatively high porosity to control the number of nuclei and relatively large pore diameters to control the amount of transported gas phase, thereby reducing deposition defects.

[0112] (A2) Take pentaethoxytantalum (which can be purchased from Sigma-Aldrich (Shanghai)), glucose (molecular weight 180.16, analytical grade, which can be purchased from Thermo Fisher Scientific (China)), anhydrous ethanol (purity ≥99.5%), and 5% dilute nitric acid.

[0113] (B2) Dissolve tantalum pentaethoxy in anhydrous ethanol at a weight ratio of tantalum pentaethoxy (Ta(OC2H5)5): anhydrous ethanol = 1:1. Then, stir with a magnetic stirrer at 400±40 rpm for 30 minutes to form a clear solution. Next, add glucose solution at a weight ratio of tantalum pentaethoxy in anhydrous ethanol to glucose = 19:5, and continue stirring at 400±40 rpm for 10 minutes to ensure complete dissolution and form a clear solution.

[0114] (C2) Slowly add dilute nitric acid dropwise to the above transparent solution using a dropper to allow for complete hydrolysis and condensation reactions. Adjust the pH of the solution to a neutral or slightly acidic range of 5.5–6.5. Stirring should be maintained throughout the pH adjustment process. Before the pH reaches 5.5–6.5, stir at a high speed of 400±40 rpm. After the pH reaches 5.5–6.5, reduce the stirring speed to 200±20 rpm and continue stirring for 30 minutes. Stop stirring once the solution gradually forms a homogeneous and stable sol. At this point, a sol with a three-dimensional network structure should be obtained.

[0115] (D2) Pour the sol into a polytetrafluoroethylene mold, then place the mold containing the sol into a constant temperature and humidity chamber and let it stand at 60±3℃ for 24-36 hours to allow it to fully gel. At this point, a sol with a three-dimensional network structure should be obtained.

[0116] (E2) Remove the gel from the mold and place it in a vacuum drying oven at 80±5℃ with a vacuum of -80KPa for 24-36 hours to remove the ethanol solvent and trace amounts of residual moisture. After drying, pour the dried gel product out of the polytetrafluoroethylene mold and place it on a graphite substrate (graphite plate).

[0117] (F2) The dried gel product is placed in a high-temperature heat treatment furnace and subjected to high-temperature carbonization under an inert Ar atmosphere (purity ≥99.99%). The carbonization temperature is 1550±20℃, the holding time is 15±1 hours, and Ar protective gas is circulated throughout the process.

[0118] (G2) The finished product is transferred to a graphite mold. The graphite purity is ≥99.9%, compressive strength is 100-150 MPa, resistivity is 7-8 μΩ·m, and melting point is ≥3850℃. It is placed in the chamber of a spark plasma sintering furnace. The vacuum pump is turned on to evacuate to 4-6 Pa, and argon gas is introduced to 0.1-0.2 MPa. The pulse power supply of the plasma sintering equipment is started, and a pulse current is applied, with the heating rate controlled at 100℃ / min. The sintering temperature is 2050℃, and the temperature is held for 15 minutes. Then, the plasma pulse current is turned off, allowing the graphite mold to cool with the furnace in the argon atmosphere.

[0119] (H2) After the finished product cools to 100℃, open the valve and slowly fill it with air until it reaches the same pressure as atmospheric pressure. Open the furnace door, remove the graphite mold, and then remove the sintered tantalum carbide porous ceramic sintered body. At this point, the volume porosity of the tantalum carbide porous ceramic sintered body should be 45±3%, the pore size should be 50-100μm, and the overall bending strength should be ≥20MPa.

[0120] (I2) Grinding process to obtain the final product - tantalum carbide porous ceramic.

[0121] The foregoing has provided a detailed description of the tantalum carbide porous ceramic and its preparation method, as well as the high-performance wafer material and semiconductor material provided by the present invention. For those skilled in the art, based on the ideas of the embodiments of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing porous tantalum carbide ceramic, characterized in that, Includes the following steps: (A) Take the following raw materials: tantalum source, glucose, anhydrous ethanol with a purity of ≥99.5%, and dilute nitric acid with a mass fraction of 5%; (B) Take tantalum source in anhydrous ethanol at a weight ratio of tantalum source: anhydrous ethanol = 1:1, stir with a magnetic stirrer at a speed of 400±40 rpm for 30 minutes to form a transparent solution, and obtain the tantalum source solution. (C) Add glucose to the tantalum source solution at a weight ratio of tantalum source solution: glucose = 30-43:9, and continue stirring at 400±40 rpm for 10 minutes to form a transparent solution and obtain the solution product. (D) Slowly add dilute nitric acid dropwise to the solution product, and stir at 400 rpm until the pH value falls between 5.5 and 6.

5. Then, change the stirring speed to 200 rpm and keep stirring for 30 minutes until a stable sol state is reached. Stop stirring to obtain the sol. (E) Pour the sol into the polytetrafluoroethylene mold, then place the mold in a constant temperature and humidity chamber and let it stand for 24-36 hours at a temperature of 60±3℃, avoiding vibration or stirring. (F) Remove the gel from the mold and place it in a vacuum drying oven. Keep it at a temperature of 80±5℃ and a vacuum of -80KPa for 24-36 hours. After drying, pour the gel onto a graphite plate for later use. (G) Take the gel into a high-temperature furnace and, under the protection of an inert atmosphere, perform high-temperature carbonization treatment at a temperature of 1400-1800℃ for 12-24 hours to obtain tantalum carbide porous ceramic.

2. The method for preparing tantalum carbide porous ceramics according to claim 1, characterized in that, It also includes the following steps: (H) Take tantalum carbide porous ceramic into a graphite mold, then place the graphite mold in the chamber of a spark plasma sintering furnace, press the upper and lower electrodes onto the upper and lower surfaces of the graphite mold respectively, close the chamber, vacuum 4-6 Pa, purge inert gas to 0.1-0.2 MPa, start the power supply, the heating rate is 100℃ / min, heat to 2000-2050℃, hold for 15-30 minutes, and then turn off the power supply and let it cool. (I) After cooling to 100°C, slowly fill with air until it is equal to atmospheric pressure, remove the graphite mold, and then remove the tantalum carbide porous ceramic structure to obtain the sintered tantalum carbide porous ceramic.

3. The method for preparing tantalum carbide porous ceramics according to claim 1, characterized in that, The tantalum source is pentaethoxytantalum (Ta(OC2H5)5) with a purity ≥99.9%.

4. The method for preparing tantalum carbide porous ceramic according to claim 2, characterized in that, The graphite mold material mentioned in step (H) is: graphite purity ≥ 99.9%, compressive strength 100~150MPa, resistivity 7-8μΩ·m, and melting point ≥ 3850℃.

5. The method for preparing tantalum carbide porous ceramic according to claim 2, characterized in that, The graphite mold described in step (H) has the following structure: a graphite base, a graphite cover plate, and a cavity. The graphite base has a concave structure with a cavity in the middle; The graphite cover plate is placed on top of the graphite base and can be movably sealed. The chamber is used to place the tantalum carbide porous ceramic, and the top and four sides of the tantalum carbide porous ceramic maintain an air gap of 2-3 mm with the interior of the graphite base.

6. The method for preparing tantalum carbide porous ceramic according to claim 2, characterized in that, It also includes the following steps: (J) Precision grinding was used to obtain polished tantalum carbide porous ceramic.

7. The method for preparing porous tantalum carbide ceramic according to any one of claims 2, 5, and 6, characterized in that, The sintered tantalum carbide porous ceramic has a volume porosity of 35-55%, a pore size that can be controlled between 30-100μm, and a bending strength of ≥20MPa.

8. A porous tantalum carbide ceramic, characterized in that, It is prepared by the method for preparing porous tantalum carbide ceramic according to any one of claims 1-7.

9. A high-performance wafer material, characterized in that, The substrate material includes tantalum carbide porous ceramic prepared according to any one of claims 1-8.

10. A semiconductor material, characterized in that, Including the high-performance wafer material prepared according to claim 9.

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