Silicon carbide material, method for producing the same, and power semiconductor

Abstract

The present disclosure provides a silicon carbide material, a preparation method thereof and a power semiconductor, and belongs to the technical field of silicon carbide material preparation 12 The carbon element in the silicon carbide material is isotope 13 C 12 The isotope 13 C has an abundance of 99% or above. The present disclosure synthesizes the silicon carbide material by using the isotope 12 C or the isotope 13 C with high abundance, significantly improves the thermal conductivity of the material, and can form the power semiconductor.

Description

Technical Field

[0001] This disclosure belongs to the field of silicon carbide material preparation technology, specifically relating to a silicon carbide material and its preparation method, and power semiconductors. Background Technology

[0002] Silicon carbide (SiC) materials possess excellent properties such as wear resistance, strong oxidation resistance, acid and alkali resistance, and strong corrosion resistance. As a wide-bandgap semiconductor material, it is widely used in semiconductor production and processing. Furthermore, SiC ceramics have advantages such as a similar coefficient of thermal expansion to Si, higher thermal conductivity, higher critical breakdown voltage, and a negative temperature coefficient of resistance, making them widely used in semiconductor devices operating in high-frequency, high-temperature, and high-pressure environments.

[0003] Currently, the main forming methods for silicon carbide material preparation include hot pressing sintering, ultra-high pressure sintering, high vacuum sintering, and microwave sintering. The carbon element in the silicon carbide formed is naturally abundant, which leads to phonon scattering and low heat transfer efficiency, thus limiting the heat dissipation efficiency of high-power devices and failing to meet the high heat dissipation requirements of high-power semiconductor devices. Summary of the Invention

[0004] This disclosure aims to at least solve one of the technical problems existing in the prior art, and to provide a silicon carbide material and its preparation method, as well as a power semiconductor.

[0005] In one aspect, this disclosure provides a method for preparing silicon carbide material, the method comprising: A substrate is provided, and the substrate is heated; A dilution gas and a reaction gas are introduced into a chemical vapor deposition (CVD) apparatus for CVD. The reaction gas includes alkanes, silanes, and a reducing gas, the dilution gas is argon, and the carbon element in the alkanes is an isotope. 12 C or isotopes 13 C, and the isotopes 12 C or isotopes 13 The abundance of C is over 99%; After chemical vapor deposition is completed, the dilution gas and reaction gas are stopped, and the silicon carbide material described above is obtained.

[0006] Optionally, the reducing gas is hydrogen.

[0007] Optionally, the diluent gas accounts for 42%-50% of the total volume of argon and hydrogen; for example, it may be selected from 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49% or 50%.

[0008] Optionally, the volumetric flow rate ratio of alkane, silane, and reducing gas is (0.2~1.2):(1.0):(15-25). Preferably, the volumetric flow rate ratio of alkane, silane, and reducing gas is 0.8:1:10, 0.8:1:12, 0.8:1:14, 0.8:1:16, 0.5:1:10, 1.0:1:10, 1.2:1:10, 1.2:1:20, or 1.2:1:25.

[0009] Optionally, the temperature for chemical vapor deposition is 1200℃-1400℃, and the deposition pressure is 2kPa-3kPa.

[0010] Optionally, the alkane is one of high-abundance carbon methane, high-abundance carbon ethane, high-abundance carbon ethylene, high-abundance carbon propane, and high-abundance carbon propylene.

[0011] Optionally, the alkane is prepared, for example, by a high-abundance carbon methane, which is formed by the following method: Prepare organic amines, viscosity modifiers, catalysts, and low-boiling-point solvents for later use; Natural carbon dioxide, organic amines, catalysts, and viscosity modifiers are introduced into the complexing tower. The carbon dioxide... 12 C complexes with organic amines to form 12 C-amine complex; The 12 The C-amine complex flows into the exchange tower, and naturally occurring carbon dioxide gas is introduced into the exchange tower. The carbon dioxide contains... 13 C and the above 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex; collection 12 CO2, the 12 The abundance of C is over 99%; A low-boiling-point solvent is added to the cracking tower, wherein the low-boiling-point solvent and 13 C-amine complexes are mixed and then heated in a cracking tower to decompose into cracking products and... 13 CO2; collection 13 CO2, the 13 The abundance of C is over 99%; Impurities in the pyrolysis products are adsorbed by the adsorbent, and organic amines are discharged.

[0012] Will 12 CO2 and 13 CO2 was catalytically reduced using a hydrogen atmosphere to the corresponding compounds. 12 CH4 or 13 CH4.

[0013] Optionally, the organic amine is selected from compounds of Formula 1 below.

[0014] R1, R2, and R3 are each independently selected as hydrogen, C1-C8 alkyl, C3-C6 heteroaryl, C3-C8 cycloalkyl, C3-C8 aryl, or C3-C8 heterocyclic; the C1-C8 alkyl is optionally substituted with 1, 2, or 3 substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, or hydroxyl; the C3-C8 cycloalkyl is optionally substituted with 1, 2, or 3 substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, or hydroxyl; the C3-C8 heteroaryl is optionally substituted with 1, 2, or 3 substituents selected from the following: C1-C3 alkyl, amino, methoxy, halogen, or hydroxyl; the heteroatom in the heteroaryl or heterocyclic alkyl is selected from N.

[0015] Optionally, R1, R2, and R3 can be independently selected as hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, methoxymethyl, ethoxymethyl, methoxyethyl, ethoxyethyl, phenyl, benzyl, phenoxymethyl, phenoxyethyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, hydroxymethyl, hydroxyethyl, hydroxypropyl, aminomethyl, aminoethyl, aminopropyl, fluoromethyl, fluoroethyl, chloromethyl, chloroethyl, bromomethyl, bromoethyl, difluoromethyl, trifluoromethyl, aryl, or heteroaryl.

[0016] Optionally, R1, R2, and R3 are independently selected from hydrogen or C1-C3 alkyl groups, wherein the C1-C3 alkyl groups are substituted with hydroxyl or methoxy groups, and R1, R2, and R3 are not simultaneously hydrogen.

[0017] Optionally, R1 is hydrogen, R2 and R3 are selected from hydrogen or C1-C3 alkyl groups, wherein the C1-C3 alkyl groups are substituted with hydroxyl or methoxy groups, and R2 and R3 are not both hydrogen.

[0018] Optionally, the organic amine is at least one selected from diethanolamine, diethylamine, ethylene glycolamine, butanediamine, triethanolamine, N-methylaniline, p-phenylenediamine, piperidine, and pyrrolidine.

[0019] Optionally, the molar ratio of carbon dioxide to organic amine is (0.20~0.80):1; for example, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1; preferably, the molar ratio is (0.3~0.6):1.

[0020] Optionally, the viscosity modifier is any one of small molecule hydrocarbons, small molecule ethers, and small molecule ketones.

[0021] Optionally, the small molecule hydrocarbon is selected from C5-C64. 10 Alkanes, C5-C 10 Cycloalkanes, C5-C 10 Aromatic hydrocarbons, C5-C 10 heteroaromatics or C5-C 10 Olefins; the C5-C 10 The alkane is optionally substituted with 1, 2, or 3 halogens; the C5-C 10 The cycloalkanes are optionally substituted with 1, 2, or 3 halogens; the C5-C 10 The aryl hydrocarbon is optionally substituted with one, two, or three halogens; the C5-C 10 The heteroaromatic hydrocarbons are optionally substituted with 1, 2 or 3 halogens or the C5-C... 10 The olefin is optionally substituted with one, two, or three halogens; preferably, the halogens include one or more of fluorine, chlorine, and bromine. More preferably, the small molecule hydrocarbon is selected from 1-chloropentane, 1,2-dichloropentane, 1-chlorohexane, n-heptane, 1-chlorooctane, dichlorocyclohexane, and chlorocyclopentane.

[0022] Optionally, the small molecule ether is represented by the general formula R1OR2, wherein R1 and R2 are independently selected from C1-C1. 10 Alkyl, C3-C 10 cycloalkyl or C5-C 10 Aryl, the C1-C 10 The alkyl group may optionally be substituted with a C1-C3 alkyl group, wherein the C5-C 10 The aryl group may be optionally substituted with a C1-C3 alkyl group; the C3-C 10 The cycloalkyl group may optionally be substituted with a C1-C3 alkyl group; preferably, R1 and R2 are independently selected from one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, phenyl, benzyl, etc. More preferably, the small molecule ether is selected from diisopropyl ether, methyl tert-butyl ether, ethyl tert-butyl ether, or di-n-propyl ether.

[0023] Optionally, the small molecule ketone is represented by the following general formula R1(C=O)R2, wherein R1 and R2 are independently selected from C1-C2. 10 Alkyl, C3-C 10 cycloalkyl, C5-C 10 Aryl groups or R1, R2 form cyclic ketones with C=O, wherein the C1-C 10 The alkyl group may optionally be substituted with a C1-C3 alkyl group, wherein the C5-C 10 The aryl group may be optionally substituted with a C1-C3 alkyl group, wherein the C3-C 10The cycloalkyl group is optionally substituted with a C1-C3 alkyl group; the cycloketone is optionally substituted with a C1-C3 alkyl group; preferably, R1 and R2 are independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, phenyl, benzyl, or R1 and R2 form a C4-C8 cycloketone with C=O; more preferably, the small molecule ketone is selected from cyclopentanone, cyclohexanone, methylcyclopentanone, methylcyclohexanone, methyl isobutyl ketone, etc.

[0024] Optionally, the viscosity modifier has a mass content of 10-30% of the organic amine mass content, for example, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%.

[0025] Optionally, the catalyst is at least one of hydrochloric acid, sulfuric acid, and carboxylic acid; the carboxylic acid has the general structural formula R1COOH or R2(COOH)2, wherein R1 is one of hydrogen, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl, and cyclopentyl, and R2 is one of methylene, ethylene, propylene, and methyl ethylene.

[0026] Optionally, the carboxylic acid is any one of acetic acid, malonic acid, and formic acid.

[0027] Optionally, the catalyst is one or more of hydrochloric acid, sulfuric acid, acetic acid, malonic acid, and formic acid.

[0028] Optionally, the mass content of the catalyst is 0.5-5% of the mass content of the organic amine. For example, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, or 5.0%.

[0029] Optionally, the low-boiling solvent is selected from C3-C6 alkanes or C3-C6 cycloalkanes, wherein the C3-C6 alkanes or C3-C6 cycloalkanes are optionally substituted with one, two, or three halogens, including fluorine, chlorine, or bromine. Preferably, the low-boiling solvent is selected from 1-chloropentane, 1,2-dichloropentane, 1-chlorohexane, dichlorocyclohexane, chlorocyclopentane, or butyrochloroethane.

[0030] Optionally, the mass content of the low-boiling-point solvent is 5%-25% of the mass content of the organic amine. For example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%.

[0031] Optionally, the temperature of the complexing tower is 25-35°C; for example, it can be 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C or 35°C.

[0032] Optionally, the temperature of the exchange tower is 10-60°C; for example, it can be 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or 60°C.

[0033] Optionally, the heating and pyrolysis temperature of the pyrolysis tower is 100-250℃; for example, it can be 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210-220℃, 230℃, 240℃ or 250℃.

[0034] In another aspect, this disclosure provides a silicon carbide material in which the carbon element is an isotope. 12 C or isotopes 13 C; where... The isotope 12 C or isotopes 13 The abundance of C is over 99%.

[0035] Optionally, the isotope 12 C or isotopes 13 The abundance of C is 99.00–99.99%.

[0036] Optionally, the grain size of the silicon carbide material is 50~500nm.

[0037] Optionally, the thermal conductivity of the silicon carbide material is 500~600 W / (m·K).

[0038] In another aspect of this disclosure, a power semiconductor is provided, the power semiconductor comprising the silicon carbide material described above.

[0039] This disclosure presents a silicon carbide material, its preparation method, and a power semiconductor. The carbon element in the silicon carbide material is an isotope. 12 C and isotopes 13 C; wherein, the isotope 12 C or isotopes 13 The abundance of C is over 99%. This disclosure utilizes high-abundance isotopes. 12 C or isotopes 13 C-synthesized silicon carbide materials significantly improve the thermal conductivity of the materials, making them suitable as power semiconductor materials. Attached Figure Description

[0040] Figure 1This is a flowchart illustrating a specific embodiment of the silicon carbide material preparation method disclosed herein. Detailed Implementation

[0041] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.

[0042] In one aspect, this disclosure proposes a silicon carbide material in which the carbon element is an isotope. 12 C or isotopes 13 C; where isotopes 12 C or isotopes 13 The abundance of C is over 99%.

[0043] In this embodiment, by employing high-abundance isotopes 12 C and isotopes 13 C-synthesized silicon carbide materials, due to 12 Carbon atoms are lightweight (neutron-free), have extremely low lattice vibration (phonon) scattering, and high thermal conductivity at room temperature. This high-abundance isotope can eliminate phonon scattering caused by naturally abundant carbon elements, and heat is efficiently transferred in the form of phonon vibrations, significantly improving the thermal conductivity of the material, which can be used as a power semiconductor.

[0044] In some other preferred embodiments, the grain size of the silicon carbide material is 50~500nm.

[0045] In some other preferred embodiments, the thermal conductivity of the silicon carbide material is 500~600 W / (m·K).

[0046] like Figure 1 As shown, in another aspect of this disclosure, a method for preparing silicon carbide material is proposed, comprising the following specific steps S110-S130: S110. Provide a substrate and heat the substrate.

[0047] It should be noted that the substrate is a carbon-based material or a silicon-based material. Preferably, the substrate includes at least one of graphite, silicon, quartz or silicon carbide.

[0048] In some preferred embodiments, the temperature for heating the substrate is 1100-1300°C.

[0049] S120. A dilution gas and a reaction gas are introduced into a chemical vapor deposition (CVD) apparatus for CVD. The reaction gas includes alkanes, silanes, and reducing gases. The dilution gas is argon, and the carbon element in the alkanes is an isotope. 12 C or isotopes 13 C, and the isotopes 12 C or isotopes 13 The abundance of C is over 99%.

[0050] In some preferred embodiments, the volume fraction of the diluent gas is 42%-50%, and the flow rate of the diluent gas is 0.5 slm to 1.5 slm.

[0051] In some preferred embodiments, the reducing gas is hydrogen.

[0052] In some preferred embodiments, the volume flow rate ratio of the alkane, silane and reducing gas is (0.2-1.2):1:(15-25).

[0053] In some other preferred embodiments, the temperature of chemical vapor deposition is 1200°C-1400°C and the deposition pressure is 2kPa-3kPa.

[0054] In some other preferred embodiments, high-abundance methane is formed using the following method: Carbon dioxide and an organic amine complexing agent are introduced into the complexing tower. The carbon dioxide contains... 12 C complexes with organic amines to form 12 C-amine complex; The 12 The C-amine complex flows into an exchange tower, and carbon dioxide gas is introduced into the exchange tower. The carbon dioxide contains... 13 C and the above 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex; The 13 C-amine complexes are pyrolyzed by heating in a pyrolysis tower into pyrolysis products and... 13 CO2; Will 12 CO2 and 13 CO2 is reduced to the corresponding alkanes in a hydrogen atmosphere, for example... 12 CO2 + 4H2 → 12 CH4 + 2H2O 13 CO2 + 4H2 → 13 CH4 + 2H2O The alkane undergoes a silanization reaction to form the corresponding silicon carbide, for example... 12 CH4 + Cl2 → 12 CH3Cl + HCl 12 CH3Cl + SiCl4 + 2Na → 12 CH3SiCl3+2NaCl.

[0055] 13 CH4 + Cl2 → 13 CH3Cl + HCl 13 CH3Cl + SiCl4 + 2Na → 13 CH3SiCl3+2NaCl.

[0056] It should be noted that the above description uses trichloromethylsilane as an example only. In other preferred embodiments, silicon carbide can also be at least one of silane, silane, propane, methylchlorosilane, dimethylchlorosilane, or trichloromethylsilane. The alkane is one of methane, ethane, ethylene, propane, or propylene. That is, the carbon isotope abundance in the silicon carbide obtained by the above method is above 99%.

[0057] It should be noted that during the synthesis of silicon carbide, the organic amine complexing agent can be at least one of primary amine, secondary amine, tertiary amine, and aromatic amine. For example, the secondary amine is an alkyl branched secondary amine, such as N-methylaniline; the primary amine is monoethanolamine; the tertiary amine is triethanolamine; and the aromatic amine is N,N-dimethylaniline.

[0058] As a further preferred embodiment, the organic amine is at least one selected from diethanolamine, butanediamine, triethanolamine, N-methylaniline, p-phenylenediamine, and cyclic secondary amines.

[0059] It should be noted that the low-boiling-point solvent can be added in the first step to mix with the organic amine, or it can be added in the complexation tower, or it can be added in the cracking tower in the third step. Similarly, the viscosity modifier and catalyst mentioned above can also be added in the first step to mix with the organic amine, or they can be added in the complexation tower, or they can be added in the exchange tower in the second step.

[0060] In some preferred embodiments, the viscosity modifier has a mass content of 10-30% of the organic amine mass content. The viscosity modifier is preferably any one of small molecule hydrocarbons, small molecule ethers, and small molecule ketones. This component can break the hydrogen bonds between amine molecules, and based on the fact that the viscosity modifier is a small molecule organic compound, it inserts into the gaps between amine molecules through the molecular dilution effect, physically separating the molecules, and further reducing the viscosity of the organic amine liquid. In this way, in the exchange reaction, the diffusion rate of the ¹³C-amine complex in the liquid phase is increased, the isotope exchange time is shortened, and energy consumption is reduced.

[0061] In some preferred embodiments, the catalyst content is 0.5-5% of the organic amine content, and the catalyst is preferably at least one of hydrochloric acid, sulfuric acid, and carboxylic acid, used for acceleration. 13 CO2 complexes with amines to form... 13 The rate of C-amine complexes is increased, reaction efficiency is improved, isotope abundance is increased, and time is further shortened, reducing the amount of organic amines used and energy consumption is reduced.

[0062] In some preferred embodiments, the low-boiling-point solvent has a mass content of 15-25% of the organic amine mass content, and the low-boiling-point solvent includes at least one of small-molecule hydrocarbons and small-molecule halogenated hydrocarbons, wherein the small-molecule hydrocarbons are preferably C5-C. 10 Chain hydrocarbons, such as C5-C 10 Straight-chain alkanes, C5-C 10 Branched alkanes have a linear molecular structure, weak intermolecular forces, and extremely low viscosity. Adding them to amine solutions can significantly reduce the viscosity of the system.

[0063] S130. After chemical vapor deposition is completed, the dilution gas and reaction gas are stopped to obtain silicon carbide material.

[0064] In another aspect of this disclosure, a power semiconductor is proposed, wherein the silicon carbide material described above is formed into a power semiconductor.

[0065] It should be noted that, since the silicon carbide material provided in this disclosure is formed from high-abundance carbon isotopes, ¹²C atoms are lightweight, have high lattice vibration (phonon) frequencies, low scattering probability, and significantly improved thermal conductivity. ¹³C atoms are heavy, have enhanced phonon scattering, and reduced thermal conductivity (approximately 10-15%). However, phonon engineering can be achieved by designing ¹²C / ¹³C superlattices to directionally control heat flow, allowing it to be applied in power semiconductors, for example, as a heat dissipation substrate for high-power devices, which can extend the device's lifespan.

[0066] The following will further illustrate silicon carbide materials and their preparation methods with specific examples: Example 1 High abundance 12 CO2 and 13 The method for CO2 preparation, and the reaction process are as follows: 12 CO2 + R2NH R2NH + 12 COO - 13 CO2 + R2NH + 12 COO - 12 CO2 + R2NH +13 COO- R2NH +13 COO - R2NH+ 13 CO2.

[0067] Where R=(HOCH2CH2)2- The specific methods include the following: S1. Carbon dioxide, an organic amine, a viscosity modifier, and a catalyst are introduced into the complexation tower. The organic amine is diethanolamine, the catalyst is formic acid, and the viscosity modifier is 1-chlorohexane. The mass content of the catalyst is 3% of the mass content of the organic amine, and the mass content of the viscosity modifier is 20% of the mass content of the organic amine. The molar ratio of carbon dioxide to organic amine is 0.35:1. At 30°C, the carbon dioxide... 12 CO2 complexes with organic amines to form... 12 C-amine complex, at this time 12 The C-amine complex flows into the exchange tower.

[0068] S2, 12 The C-amine complex flows into the exchange column, and carbon dioxide gas is introduced into the exchange column. At 40°C, the carbon dioxide... 13 CO2 and 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex, at this time 12 CO2 is collected in the exhaust exchange tower. 13 The C-amine complex further flows into the cracking tower.

[0069] S3. Add the low-boiling-point solvent chlorobutane to the cracking tower, and... 13 The C-amine complex mixture was heated to 105°C and then pyrolyzed into pyrolysis products and... 13 CO2, wherein the low-boiling-point solvent has a mass content of 15% of the organic amine mass content, is collected. 13 CO2.

[0070] S4. In the impurity removal tower, the pyrolysis products are adsorbed by the adsorbent to form organic amines and impurities. The organic amines further participate in the complexation reaction in step S1.

[0071] Specifically, the impurity removal tower can be a fixed-bed adsorption tower, where the adsorbent is filled from top to bottom, and the amine solution flows axially through the bed from top to bottom. Impurities are trapped by the adsorbent, and the purified amine solution flows out from the bottom of the tower. For example, the upper layer can be filled with modified activated carbon, and the lower layer can be filled with oxygen-modified activated carbon. The modified activated carbon is a porous activated carbon with oxygen-modified surface and a specific surface area ≥400 m². 2 / g, oxygen content 5~15wt%.

[0072] Detection method: Inductively coupled plasma mass spectrometry.

[0073] Collected after testing 12 CO2 and 13 CO2 abundance, 13 C abundance 99.992%, 12 C abundance: 99.995%.

[0074] Example 2 S1. Carbon dioxide, an organic amine, a viscosity modifier, and a catalyst are introduced into the complexation tower. The organic amine is diethanolamine, the catalyst is malonic acid, and the viscosity modifier is 1-chlorohexane. The mass content of the catalyst is 3% of the organic amine, the mass content of the viscosity modifier is 20% of the organic amine, and the molar ratio of carbon dioxide to organic amine is 0.4:1. At 25°C, the carbon dioxide... 12 CO2 complexes with the complexing agent organic amine to form... 12 C-amine complex, at this time 12 The C-amine complex flows into the exchange tower.

[0075] S2, 12 The C-amine complex flows into the exchange column, and carbon dioxide gas is introduced into the exchange column. At 35°C, the carbon dioxide... 13 CO2 and 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex, at this time 12 CO2 is collected in the exhaust exchange tower. 13 The C-amine complex further flows into the cracking tower.

[0076] S3. Add the low-boiling-point solvent chlorobutane to the cracking tower. The mass content of the low-boiling-point solvent is 15% of the mass content of the organic amine. 13 The C-amine complex mixture was heated to 110°C and then pyrolyzed into pyrolysis products and... 13 CO2, collection 12 CO3.

[0077] S4. The pyrolysis products form complexing agents and impurities in the impurity removal tower.

[0078] Specifically, the impurity removal tower can be a fixed-bed adsorption tower, with the adsorbent filled from top to bottom. The amine solution flows axially through the bed from top to bottom, and impurities are trapped by the adsorbent. The purified amine solution flows out from the bottom of the tower. For example, modified activated carbon can be filled in both the upper and lower layers. The modified activated carbon is a porous activated carbon with oxygen-modified surface and a specific surface area ≥400 m². 2 / g, oxygen content 5~15wt%.

[0079] Collected after testing 12 CO2 and 13 CO2 abundance, 13 C abundance 99.997%, 12 C abundance: 99.995%.

[0080] Example 3 S1. Carbon dioxide, an organic amine, a viscosity modifier, and a catalyst are introduced into the complexation tower. The organic amine is diethanolamine, the catalyst is malonic acid, and the viscosity modifier is diisopropyl ether. The mass content of the catalyst is 3% of the mass content of the organic amine, and the mass content of the viscosity modifier is 20% of the mass content of the organic amine. The molar ratio of carbon dioxide to diethanolamine is 0.45:1. At 32°C, the carbon dioxide... 12 CO2 complexes with the complexing agent organic amine to form... 12 C-amine complex, at this time 12 The C-amine complex flows into the exchange tower.

[0081] S2, 12 The C-amine complex flows into the exchange column, and carbon dioxide gas is introduced into the exchange column. At 50°C, the carbon dioxide... 13 CO2 and 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex, at this time 12 CO2 is collected in the exhaust exchange tower. 13 The C-amine complex further flows into the cracking tower.

[0082] S3. Add butane, a low-boiling-point solvent, to the cracking tower. The mass content of the low-boiling-point solvent is 15% of the mass content of the organic amine. 13 The C-amine complex was decomposed in a cracking column at 100°C into cracking products and... 13 CO2, collection 13 CO2.

[0083] S4. The pyrolysis products form complexing agents and impurities in the impurity removal tower.

[0084] Specifically, the impurity removal tower can be a fixed-bed adsorption tower, with the adsorbent filled from top to bottom. The amine solution flows axially through the bed from top to bottom, and impurities are trapped by the adsorbent. The purified amine solution flows out from the bottom of the tower. For example, modified activated carbon can be filled in both the upper and lower layers. The modified activated carbon is a porous activated carbon with oxygen-modified surface and a specific surface area ≥400 m². 2 / g, oxygen content 5~15wt%.

[0085] Collected after testing 12 CO2 and 13CO2 abundance, 13 C abundance 99.995%, 12 C abundance: 99.995%.

[0086] Example 4 S1. Carbon dioxide, an organic amine, a viscosity modifier, and a catalyst are introduced into the complexation tower. The organic amine is diethanolamine, the catalyst is formic acid, the viscosity modifier is n-heptanone, the mass content of the catalyst is 3% of the organic amine, and the mass content of the viscosity modifier is 20% of the organic amine. The molar ratio of carbon dioxide to diethanolamine is 0.5:1. At 38°C, the carbon dioxide... 12 CO2 complexes with the complexing agent organic amine to form... 12 C-amine complex, at this time 12 The C-amine complex flows into the exchange tower.

[0087] S2, 12 The C-amine complex flows into the exchange column, and carbon dioxide gas is introduced into the exchange column. At 50°C, the carbon dioxide... 13 CO2 and 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex, at this time 12 CO2 is collected in the exhaust exchange tower. 13 The C-amine complex further flows into the cracking tower.

[0088] S3. Add low-boiling-point solvent chloropropane to the cracking tower. The mass content of the low-boiling-point solvent is 15% of the mass content of the organic amine. 13 The C-amine complex was decomposed in a cracking tower at 120°C into cracking products and... 13 CO2, collection 13 CO2.

[0089] S4. The pyrolysis products form complexing agents and impurities in the impurity removal tower.

[0090] Specifically, the impurity removal tower can be a fixed-bed adsorption tower, with the adsorbent filled from top to bottom. The amine solution flows axially through the bed from top to bottom, and impurities are trapped by the adsorbent. The purified amine solution flows out from the bottom of the tower. For example, modified activated carbon can be filled in both the upper and lower layers. The modified activated carbon is a porous activated carbon with oxygen-modified surface and a specific surface area ≥400 m². 2 / g, oxygen content 5~15wt%.

[0091] Collected after testing 12 CO2 and 13 CO2 abundance, 13 C abundance 99.992%, 12 C abundance: 99.995%.

[0092] Example 5 This example illustrates a method for separating carbon isotopes, with the following reaction process: 12 CO2 + RNH2 RNH2 + 12 COO - 13 CO2 + RNH2 + 12 COO - 12 CO2 + RNH2 + 13 COO - RNH2 +13 COO - RNH2+ 13 CO2.

[0093] R=HO-CH2-CH2- The specific methods include the following: S1. Carbon dioxide, an organic amine, a viscosity modifier, and a catalyst are introduced into the complexation tower. The organic amine is ethylene glycol amine, the catalyst is formic acid, and the viscosity modifier is ethyl tert-butyl ether. The mass content of the catalyst is 3% of the organic amine, and the mass content of the viscosity modifier is 20% of the organic amine. The molar ratio of carbon dioxide to diethanolamine is 0.5:1. At 25°C, the carbon dioxide... 12 CO2 complexes with the complexing agent organic amine to form... 12 C-amine complex, at this time 12 The C-amine complex flows into the exchange tower.

[0094] S2, 12 The C-amine complex flows into the exchange column, and carbon dioxide gas is introduced into the exchange column. At 55°C, the carbon dioxide... 13 CO2 and 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex, at this time 12 CO2 is collected in the exhaust exchange tower. 13 The C-amine complex further flows into the cracking tower.

[0095] S3. Add the low-boiling-point solvent 1-chloropentane to the cracking tower. The mass content of the low-boiling-point solvent is 15% of the mass content of the organic amine. 13 The C-amine complex mixture was heated to 125°C and then pyrolyzed into pyrolysis products and... 13 CO2, collection 13CO2.

[0096] S4. The pyrolysis products form complexing agents and impurities in the impurity removal tower.

[0097] Specifically, the impurity removal tower can be a fixed-bed adsorption tower, with the adsorbent filled from top to bottom. The amine solution flows axially through the bed from top to bottom, and impurities are trapped by the adsorbent. The purified amine solution flows out from the bottom of the tower. For example, modified activated carbon can be filled in both the upper and lower layers. The modified activated carbon is a porous activated carbon with oxygen-modified surface and a specific surface area ≥400 m². 2 / g, oxygen content 5~15wt%.

[0098] Detection and collection 12 CO2 and 13 CO2 abundance, 13 C abundance 99.999%, 12 C abundance: 99.995%.

[0099] Example 6 This high abundance 12 CO2 and 13 The CO2 preparation method involves the following reaction: 12 CO2 + H2O + R3N R3NH + H¹²CO3 - 13 CO2 + R3NH + H¹²CO3 - 12 CO2+ R3NH + H 13 CO3 -

[0100] R3NH + H 13 CO3 - R3N+ 13 CO2 + H2O Where R=(HOCH2CH2)3- S1. Carbon dioxide, organic amine, viscosity modifier, and catalyst are introduced into the complexation tower. The catalyst is acetic acid, and the viscosity modifier is cyclohexanone. The mass content of the catalyst is 3% of the organic amine, and the mass content of the viscosity modifier is 20% of the organic amine. The molar ratio of carbon dioxide to triethanolamine is 0.6:1. At 40°C, the carbon dioxide... 12 CO2 complexes with the complexing agent organic amine to form... 12C-amine complex, at this time 12 The C-amine complex flows into the exchange tower.

[0101] S2, 12 The C-amine complex flows into the exchange column, and carbon dioxide gas is introduced into the exchange column. At 55°C, the carbon dioxide... 13 CO2 and 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex, at this time 12 CO2 is collected in the exhaust exchange tower. 13 The C-amine complex further flows into the cracking tower.

[0102] S3. Add 1,2-dichloropentane, a low-boiling-point solvent, to the cracking tower. The mass content of the low-boiling-point solvent is 15% of the mass content of the organic amine. 13 The C-amine complex was decomposed in a cracking column at 130°C into cracking products and... 13 CO2, collection 13 CO2.

[0103] S4. The pyrolysis products form complexing agents and impurities in the impurity removal tower.

[0104] Specifically, the impurity removal tower can be a fixed-bed adsorption tower, with the adsorbent filled from top to bottom. The amine solution flows axially through the bed from top to bottom, and impurities are trapped by the adsorbent. The purified amine solution flows out from the bottom of the tower. For example, modified activated carbon can be filled in both the upper and lower layers. The modified activated carbon is a porous activated carbon with oxygen-modified surface and a specific surface area ≥400 m². 2 / g, oxygen content 5~15wt%.

[0105] Detection and collection 12 CO2 and 13 CO2 abundance, 13 C abundance 99.992%, 12 C abundance: 99.995%.

[0106] Example 7 S1. Carbon dioxide, an organic amine, a viscosity modifier, and a catalyst are introduced into the complexation tower. The organic amine is N-methylaniline, the catalyst is sulfuric acid, the viscosity modifier is dichlorocyclohexane, and the mass content of dichlorocyclohexane is 20% of the organic amine. The mass content of sulfuric acid is 3% of the organic amine. The molar ratio of carbon dioxide to organic amine is 0.25:1. At 25°C, the carbon dioxide... 12 CO2 complexes with the complexing agent organic amine to form... 12 C-amine complex, at this time 12 The C-amine complex flows into the exchange tower.

[0107] S2, 12 The C-amine complex flows into the exchange column, and carbon dioxide gas is introduced into the exchange column. At 45°C, the carbon dioxide... 13 CO2 and 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex, at this time 12 CO2 is collected in the exhaust exchange tower. 13 The C-amine complex further flows into the cracking tower.

[0108] S3. Add the low-boiling-point solvent chlorobutane to the cracking tower. The mass content of the low-boiling-point solvent is 15% of the mass content of the organic amine. 13 The C-amine complex mixture was heated to 130°C and then pyrolyzed into pyrolysis products and... 13 CO2, collection 13 CO 2。

[0109] S4. The pyrolysis products form complexing agents and impurities in the impurity removal tower.

[0110] Specifically, the impurity removal tower can be a fixed-bed adsorption tower, with the adsorbent filled from top to bottom. The amine solution flows axially through the bed from top to bottom, and impurities are trapped by the adsorbent. The purified amine solution flows out from the bottom of the tower. For example, modified activated carbon can be filled in both the upper and lower layers. The modified activated carbon is a porous activated carbon with oxygen-modified surface and a specific surface area ≥400 m². 2 / g, oxygen content 5~15wt%.

[0111] Detection and collection 12 CO2 and 13 CO2 abundance, 13 C abundance 99.995%, 12 C abundance: 99.992%.

[0112] Examples 8-14: The high abundance obtained in Examples 1-7 13 CO2 and 12 CO2 reacts with H2 to form 13 CH4 12 A mixture of CH4 and H2O gases. The reaction equation is as follows: 12 CO2 + 4H2 → 12 CH4 + 2H2O 13 CO2 + 4H2 → 13 CH4 + 2H2O The reaction temperature is 300-400℃ and the reaction pressure is 1-2 MPa.

[0113] After testing 12 CH4 abundance greater than 99%, 13 CH4 abundance greater than 99%.

[0114] Examples 15-21 This example illustrates a method for preparing silicon carbide materials: Take Examples 8-14 12 CH4 and 13 CH4 forms a high abundance 12 CH3SiCl3 and 13 CH3SiCl3.

[0115] 12 CH4 + Cl2 → 12 CH3Cl + HCl 12 CH3Cl + SiCl4 + 2Na → 12 CH3SiCl3+2NaCl.

[0116] 13 CH4 + Cl2 → 13 CH3Cl + HCl 13 CH3Cl + SiCl4 + 2Na → 13 CH3SiCl3+2NaCl.

[0117] A silicon-based material substrate is provided, and the silicon-based material substrate is heated at 1250°C; Chemical vapor deposition (CVD) is performed by introducing dilution gas and reaction gas into a chemical vapor deposition (CVD) apparatus. The deposition temperature is 1250°C and the pressure is 2.5 kPa. The reaction gas includes CH4, SiCl4, and the reducing gas H2, with a volumetric flow rate ratio of 0.8:1:10. The dilution gas is argon, and the carbon element in the alkane is an isotope. 12 C and isotopes 13 C, with an abundance of 99%; After chemical vapor deposition is completed, the dilution and reactant gases are stopped, yielding silicon carbide material. The silicon carbide is then analyzed for... 12 C 13 C abundance is >99%.

[0118] The thermal conductivity of the silicon carbide material in Examples 15-21 is 500~600 W / (m·K), which indicates that the silicon carbide material prepared in this example has a high thermal conductivity.

[0119] Example 22 This example illustrates a method for preparing silicon carbide materials: Forming high abundance 12 CH3SiCl3 and13 CH3SiCl3, the specific process is consistent with the previous description; A silicon-based material substrate is provided, and the silicon-based material substrate is heated at 1400°C; Chemical vapor deposition (CVD) is performed by introducing dilution gas and reaction gas into a chemical vapor deposition (CVD) apparatus. The deposition temperature is 1400°C and the pressure is 3.0 kPa. The reaction gas includes alkanes, silanes, and reducing gases, specifically CH4, SiCl4, and H2, with a volumetric flow rate ratio of 1:1:10. The dilution gas is argon, and the carbon element in the alkanes is an isotope. 12 C and isotopes 13 C, with an abundance of 99%; After chemical vapor deposition is completed, the dilution and reactant gases are stopped, yielding silicon carbide material. The silicon carbide is then analyzed for... 12 C 13 C abundance is >99%.

[0120] The thermal conductivity of the silicon carbide material in Example 22 is 580 W / (m·K), which indicates that the silicon carbide material prepared in Example 22 has a high thermal conductivity.

[0121] Example 23: The carbon source gas is high-abundance ethylene. The high abundance of Example 1 13 CO2 and 12 CO2 reacts with H2 to form 13 C2H4, 12 A mixture of C2H4 gases. The reaction equation is as follows: 2 12 CO2 + 6H2 → 12 C2H4+4H2O 2 13 CO2 + 6H2 → 13 C2H4+4H2O The reaction temperature is 380-420°C, and the reaction pressure is 3.0-5.0 MPa.

[0122] After testing 12 C2H2 abundance greater than 99%, 13 C2H2 abundance is greater than 99%.

[0123] Example 24: The carbon source gas is high-abundance ethane. Take the high abundance of Example 1 13 CO2 and 12 CO2 reacts with H2 to form 13 C2H6, 12 The reaction equation for the C2H6 mixture is as follows: 212 CO2 + 7H2 → 12 C2H6+4H2O 2 13 CO2 + 7H2 → 13 C2H6+4H2O The reaction temperature is 260-320°C, and the reaction pressure is 2.0-3.5 MPa.

[0124] After testing 12 C2H2 abundance greater than 99%, 13 C2H2 abundance is greater than 99%.

[0125] Example 25 Take Example 23 13 C2H4, 12 Silicon carbide materials were prepared from C2H4 and SiCl4 according to the method in Example 22.

[0126] Example 26 Take Example 24 13 C2H6, 12 Silicon carbide materials were prepared from C2H6 and SiCl4 according to the method in Example 22.

[0127] The CO2-H2 reduction reaction to produce alkanes and boron carbide described in this invention are both existing technologies, and the specific process parameters will not be elaborated further.

[0128] Experimental Example 1 Comparative Example 1 This example provides a method for preparing silicon carbide material according to the method of Example 22, except that methane is prepared using natural carbon dioxide (¹³C with a natural abundance of about 1.1%), while the other methods are the same.

[0129] A silicon-based material substrate is provided, and the silicon-based material substrate is heated at 1250°C; The dilution gas and the reaction gas are introduced into a chemical vapor deposition (CVD) apparatus for CVD deposition. The deposition temperature is 1250°C and the pressure is 2.5 kPa. The reaction gas includes alkanes, silanes, and reducing gases. The dilution gas is argon. The carbon element in the alkanes and silanes is natural carbon dioxide (natural abundance of approximately 1.1%¹³C). After chemical vapor deposition is completed, the dilution gas and reaction gas are stopped, and silicon carbide material is obtained.

[0130] The thermal conductivity of the silicon carbide material in Comparative Example 1 is 470 W / (m·K), which indicates that the thermal conductivity of the silicon carbide material prepared in Comparative Example 1 is relatively low.

[0131] Synergistic effect of each component of the complexing agent in Experiment Example 2 The complexing agent components of Comparative Examples 1-5 are shown in the table below. Other methods and parameters were prepared according to Example 1.

[0132] The results are as follows: (1) Significant catalytic effect: In the complete formulation (organic amine + catalyst + viscosity modifier + low melting point solvent, Example 1), the ¹³ CO₂ abundance reached 99.99%, and the reaction time was only 5 hours, which was the best among all experimental groups. In contrast, the abundance of the formulation without catalyst (Comparative Example 1, organic amine + viscosity modifier + low melting point solvent) decreased to 99.82%, and the reaction time was extended to 12 hours, indicating that the catalyst has a decisive promoting effect on the reaction rate and isotope selectivity.

[0133] (2) Lacking viscosity modifier (Comparative Example 2, organic amine + catalyst + low melting point solvent): abundance 99.78%, reaction time 8 hours; (3) Lacking low melting point solvent (Comparative Example 4, organic amine + catalyst + viscosity modifier): abundance 99.79%, reaction time 6.5 hours.

[0134] Comparative Examples 2 and 4 both showed inferior performance compared to the complete formulation, indicating that viscosity modifiers help improve mass transfer, while low-melting-point solvents are beneficial for maintaining homogeneity in the reaction system and for low-temperature operation. Both viscosity modifiers and low-melting-point solvents are indispensable: the absence of either component alone will lead to a decline in performance.

[0135] (4) The effect of using organic amine alone is the worst: when organic amine is used as the complexing agent (Comparative Example 1), the abundance of ¹³CO2 is only 97.53%, and the reaction time is as long as 12 hours, which confirms that a single component cannot meet the requirements of efficient enrichment.

[0136] In summary, the optimal complexing agent composition is a quaternary complex system consisting of organic amine, catalyst, viscosity modifier, and low-melting-point solvent. While ensuring a high abundance of 99.99%, it can shorten the reaction time to 5 hours, demonstrating significant comprehensive performance advantages.

[0137] This disclosure presents a silicon carbide material, its preparation method, and a power semiconductor, which have the following advantages over the prior art: This disclosure utilizes high-abundance isotopes 12 C and isotopes 13 C, by adjusting the ratio of the two, a silicon carbide material with a high thermal conductivity is formed, which can meet the heat dissipation requirements of power semiconductors.

[0138] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A method for preparing silicon carbide material, characterized in that, The preparation method includes: A substrate is provided, and the substrate is heated; A dilution gas and a reaction gas are introduced into a chemical vapor deposition (CVD) apparatus for CVD. The reaction gas includes alkanes, silanes, and a reducing gas, the dilution gas is argon, and the carbon element in the alkanes is an isotope. 12 C or isotopes 13 C, and the isotopes 12 C or isotopes 13 The abundance of C is over 99%; After chemical vapor deposition is completed, the dilution gas and reaction gas are stopped, and silicon carbide material is obtained.

2. The preparation method according to claim 1, characterized in that, The volume fraction of the diluent gas is 42%-50%.

3. The preparation method according to claim 1, characterized in that, The alkane, The volumetric flow rate ratio of silane to reducing gas is (0.2-1.2):1.0:(15-25).

4. The preparation method according to claim 1, characterized in that, The temperature for chemical vapor deposition is 1200℃-1400℃, and the deposition pressure is 2kPa-3kPa.

5. The preparation method according to claim 1, characterized in that, The alkane is one of methane, ethane, ethylene, propane, and propylene.

6. The preparation method according to claim 5, characterized in that, The alkane is formed using the following method: Prepare organic amines, viscosity modifiers, catalysts, and low-boiling-point solvents for later use; Carbon dioxide, organic amines, a catalyst, and a viscosity modifier are introduced into the complexing tower. The carbon dioxide... 12 CO2 complexes with organic amines to form... 12 C-amine complex; The 12 The C-amine complex flows into an exchange tower, and carbon dioxide gas is introduced into the exchange tower. The carbon dioxide contains... 13 CO2 and the above 12 The C-amine complex undergoes an exchange reaction to generate 12 CO2 and 13 C-amine complex; A low-boiling-point solvent is added to the cracking tower, wherein the low-boiling-point solvent and 13 C-amine complexes are mixed and then heated in a cracking tower to decompose into cracking products and... 13 CO2; Impurities in the pyrolysis products are adsorbed by the adsorbent, and organic amines are discharged. Will 12 CO2 or 13 CO2 is catalytically reduced using a reducing gas to the corresponding C-12 and C-13 alkanes, respectively.

7. A silicon carbide material, characterized in that, The silicon carbide material is prepared by the preparation method described in claims 1-6, wherein the carbon element in the silicon carbide material is a high-abundance isotope. 12 C or isotopes 13 C; wherein, the isotope 12 C or isotopes 13 The abundance of C is over 99%.

8. The silicon carbide material according to claim 7, characterized in that, The grain size of the silicon carbide material is 50~500nm.

9. The silicon carbide material according to claim 7, characterized in that, The thermal conductivity of the silicon carbide material is 500~600 W / (m·K).

10. A power semiconductor, characterized in that, The power semiconductor includes the silicon carbide material as described in any one of claims 7-9.

Images