Chemical vapor infiltration surface hole sealing method of recrystallized silicon carbide sintered body for semiconductor
Through phased chemical vapor-phase permeation technology, the surface of recrystallized silicon carbide sintered body is sealed and coated, which solves the problems of impurities volatilization and coating roughness at high temperatures, and achieves a high purity and flatness coating, improving the quality of semiconductor devices.
Patent Information
- Application Number
- CN202510458224.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2025-08-01
AI Technical Summary
The existing recrystallized silicon carbide sintered bodies are prone to cause impurities volatile pollution and coating roughness exceeding the standard in high temperature environments, which is difficult to meet the high purity and flatness requirements of semiconductor devices.
Using staged chemical vapor-phase permeation technology, using methyl trichlorosilane (MTS) as raw material, pore sealing and coating are carried out on the surface of recrystallized silicon carbide sintered body by precisely regulating the molar ratio, deposition temperature and pressure, to achieve pore filling and growth of β-SiC coating.
Effectively seal the pores of the substrate, prevent impurities from evaporating, improve the density and flatness of the coating, and improve the yield of semiconductor devices.
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Figure CN120400792A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of semiconductor high-temperature protection coating preparation, and particularly relates to a chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors. Background Art
[0002] In semiconductor high-temperature processes, the susceptor components of diffusion furnaces need to serve in an extreme thermal field environment above 1250°C for a long time. In the prior art, although using a recrystallized silicon carbide sintered body with a purity ≥ 99.99% (4N grade) as the susceptor matrix material has a cost advantage, its porous microstructure (porosity > 10%) easily leads to two technical defects: First, low-purity substances (such as metal impurities) inside the matrix volatilize along the pore channels under high-temperature conditions, causing particle contamination on the wafer surface; Second, the pore distribution on the sintered body surface is uneven (pore diameter range 0.1 - 5 μm). When directly depositing a silicon carbide coating, the heterogeneous nucleation effect at the pore edges will significantly increase the surface roughness of the coating, making it difficult to meet the flatness requirements of semiconductor-level contact interfaces. Summary of the Invention
[0003] The purpose of the present invention is to provide a chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors, focusing on solving the problems of easy impurity volatilization pollution and excessive coating roughness in the high-temperature environment of the matrix.
[0004] To achieve the above purpose, the present invention adopts the following technical solutions:
[0005] A chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors, using recrystallized silicon carbide sintered bodies with different bulk densities as the matrix, adopting a staged chemical vapor infiltration technique, using the gas of methyltrichlorosilane (MTS) as the raw material, and the gas system introduced into the reaction chamber is the MTS-H2-Ar system, including the following steps:
[0006] (1) Ultrasonically clean a recrystallized silicon carbide sintered body with a bulk density of 2.0 - 3.2 g / cm 3 in absolute ethanol for 15 min, dry it at 150°C for 15 min, and then place it on the sample stage as the matrix for use;
[0007] (2) When chemically vapor infiltrating and surface sealing the recrystallized silicon carbide sintered body matrix, the molar ratio of the raw material gases is MTS:H2 = 0.01 - 1, argon is introduced, the deposition temperature is 1000 - 1400°C, the pressure is 1 - 5 kPa, the deposition time is 1 - 10 h, and then directly apply the coating;
[0008] (3) When coating the surface of the recrystallized silicon carbide sintered body matrix by chemical vapor infiltration and surface sealing, the molar ratio of the raw material gases is MTS:H2 = 0.01 - 1, argon gas is introduced, the deposition temperature is 1200 - 1600 °C, the pressure is 5 - 10 kPa, the deposition time is 1 - 10 h, and after the deposition is completed, it is cooled to room temperature in the furnace.
[0009] For the chemical vapor infiltration surface sealing method of the recrystallized silicon carbide sintered body for semiconductors, preferably, in step (1), the bulk density of the recrystallized silicon carbide sintered body is 2.64 g / cm 3 .
[0010] For the chemical vapor infiltration surface sealing method of the recrystallized silicon carbide sintered body for semiconductors, in step (2), the flow rate of the raw material gas is 100 - 10000 sccm, and the flow rate of argon gas is 100 - 10000 sccm.
[0011] For the chemical vapor infiltration surface sealing method of the recrystallized silicon carbide sintered body for semiconductors, preferably, in step (2), MTS:H2 = 0.02, the flow rate of the raw material gas is 500 sccm, the flow rate of argon gas is 1500 sccm, the deposition temperature is 1050 °C, the pressure is 2 kPa, and the deposition time is 2 h.
[0012] For the chemical vapor infiltration surface sealing method of the recrystallized silicon carbide sintered body for semiconductors, in step (3), the flow rate of the raw material gas is 100 - 10000 sccm, and the flow rate of argon gas is 100 - 10000 sccm.
[0013] For the chemical vapor infiltration surface sealing method of the recrystallized silicon carbide sintered body for semiconductors, preferably, in step (3), MTS:H2 = 0.1, the flow rate of the raw material gas is 600 sccm, the flow rate of argon gas is 1500 sccm, the deposition temperature is 1400 °C, the pressure is 8 kPa, and the deposition time is 2 h.
[0014] For the chemical vapor infiltration surface sealing method of the recrystallized silicon carbide sintered body for semiconductors, filling and sealing are achieved within a depth of 1 - 1000 μm on the surface of the recrystallized silicon carbide sintered body matrix, and the thickness of the SiC coating is 1 - 300 μm.
[0015] For the chemical vapor infiltration surface sealing method of the recrystallized silicon carbide sintered body for semiconductors, preferably, the filling depth on the surface of the recrystallized silicon carbide sintered body matrix is 10 - 500 μm, and the thickness of the SiC coating is 10 - 100 μm.
[0016] The design concept of the present invention is:
[0017] Aiming at the technical bottlenecks that the porous recrystallized silicon carbide sintered body matrix is prone to cause impurity volatilization pollution and coating roughness exceeding the standard in a high-temperature environment of 1250 °C, the present invention proposes a chemical vapor infiltration surface sealing method for the recrystallized silicon carbide sintered body used in semiconductors: implementing a staged chemical vapor infiltration (CVI) process on the recrystallized silicon carbide matrix: 1. Sealing stage, in the MTS-H2 raw material system, by precisely controlling the molar ratio (MTS:H2 = 0.01 - 1), deposition temperature (1000 - 1400 °C) and pressure (1 - 5 kPa), filling and sealing are achieved within a depth of 10 - 500 μm on the matrix surface; 2. Coating stage, epitaxially growing a 6N-level β-SiC continuous coating in the low-pressure high-temperature zone (1200 - 1600 °C, 5 - 10 kPa). This process solves the synergistic problem of pore closure and high-purity deposition in stages, making the surface of the crystal boat have both ultra-high chemical stability and flatness, while avoiding the high-temperature escape of matrix impurities, and can significantly improve the yield rate of semiconductor devices.
[0018] The advantages and beneficial effects of the present invention are:
[0019] 1. Through the staged chemical vapor infiltration process of the present invention, the surface sealing effect is good, the prepared coating structure is dense, and it combines well with the recrystallized SiC sintered body matrix, effectively preventing the volatilization pollution of internal impurities in the matrix at high temperatures.
[0020] 2. Through the staged chemical vapor infiltration process of the present invention, the β-SiC coating grown in the second stage is dense and the surface is flat. Description of the Drawings
[0021] Figure 1 is the surface morphology diagram of the recrystallized silicon carbide sintered body with a bulk density of 2.64 g / cm 3 after CVI surface sealing and coating.
[0022] Figure 2 is the cross-sectional morphology diagram of the recrystallized silicon carbide sintered body with a bulk density of 2.64 g / cm 3 after CVI surface sealing and coating.
[0023] Figure 3 is the X-ray diffraction (XRD) pattern of the recrystallized silicon carbide sintered body with a bulk density of 2.64 g / cm 3 after CVI surface sealing and coating; in the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (a.u.).
[0024] Figure 4 is the surface roughness test curve of the recrystallized silicon carbide sintered body with a bulk density of 2.64 g / cm 3 after CVI surface sealing and coating.
[0025] Figure 5 Is the surface morphology diagram of the CVI surface sealing and coating of the recrystallized silicon carbide sintered body with a bulk density of 2.35 g / cm 3 ; In the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (a.u.).
[0026] Figure 6 Is the surface morphology diagram of the CVI surface sealing and coating of the recrystallized silicon carbide sintered body with a bulk density of 2.35 g / cm 3 ; In the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (a.u.).
[0027] Figure 7 Is the XRD pattern of the CVI surface sealing and coating of the recrystallized silicon carbide sintered body with a bulk density of 2.35 g / cm 3 ; In the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (a.u.).
[0028] Figure 8 Is the surface roughness test curve of the CVI surface sealing and coating of the recrystallized silicon carbide sintered body with a bulk density of 2.35 g / cm 3 ; In the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (a.u.).
[0029] Figure 9 Is the surface morphology diagram of the CVI surface sealing and coating of the recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm 3 ; In the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (a.u.).
[0030] Figure 10 Is the cross-sectional morphology diagram of the CVI surface sealing and coating of the recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm 3 ; In the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (a.u.).
[0031] Figure 11 Is the XRD pattern of the CVI surface sealing and coating of the recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm 3 ; In the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (a.u.).
[0032] Figure 12 Is the surface roughness test curve of the CVI surface sealing and coating of the recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm 3 ; In the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (a.u.). Detailed implementation manners
[0033] In the specific implementation process, the present invention proposes a chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors. Using recrystallized silicon carbide sintered bodies with different bulk densities as the substrate, a staged chemical vapor infiltration technique is adopted, using methyltrichlorosilane (MTS) as the raw material, and the gas system introduced into the reaction chamber is selected as the MTS-H2-Ar system to perform chemical vapor infiltration surface sealing and coating on the recrystallized silicon carbide sintered body substrate.
[0034] The following further describes the specific embodiments of the present invention. It should be noted here that the description of these embodiments is used to help understand the present invention, but does not limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0035] The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples are all commercially available through conventional channels unless otherwise specified.
[0036] Example 1
[0037] In this example, a chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors includes the following steps:
[0038] (1) Using high-purity silicon carbide powder (purity ≥ 99.99 wt%) as the raw material, a recrystallized silicon carbide sintered body with a bulk density of 2.64 g / cm 3 was prepared by the recrystallization sintering technique under an Ar atmosphere, at 2400 °C, and a pressure of 125000 Pa.
[0039] (2) The recrystallized silicon carbide sintered body with a bulk density of 2.64 g / cm 3 was ultrasonically cleaned in absolute ethanol for 15 min, dried at 150 °C for 15 min, and then placed on the sample stage as the substrate for use.
[0040] (3) When chemically vapor infiltrating and surface sealing the recrystallized silicon carbide sintered body substrate, a gas mixture of methyltrichlorosilane and hydrogen was used as the source gas. The molar ratio of the source gas was MTS:H2 = 0.02, the flow rate of the source gas was 500 sccm, the flow rate of argon was 1500 sccm, the deposition temperature was 1050 °C, the pressure was 2 kPa, and the deposition time was 2 h.
[0041] Then, the coating was directly carried out.
[0042] (4) When coating after chemically vapor infiltrating and surface sealing the recrystallized silicon carbide sintered body substrate, a gas mixture of methyltrichlorosilane and hydrogen was used as the source gas. The molar ratio of the source gas was MTS:H2 = 0.1, the flow rate of the source gas was 600 sccm, the flow rate of argon was 1500 sccm, the deposition temperature was 1400 °C, the pressure was 8 kPa, the deposition time was 2 h, and after the deposition, it was cooled to room temperature in the furnace. Filling and sealing were achieved within a depth of 50 μm on the surface of the recrystallized silicon carbide substrate, and the thickness of the β-SiC coating was 90 μm.
[0043] In this embodiment, the sealing effect on the surface of the recrystallized silicon carbide sintered body matrix is good, the prepared coating has a dense structure, good bonding with the recrystallized silicon carbide sintered body matrix, and can provide excellent protection for the recrystallized silicon carbide sintered body matrix.
[0044] Example 2
[0045] In this embodiment, a chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors includes the following steps:
[0046] (1) Using high-purity silicon carbide powder (purity ≥ 99.99 wt%) as the raw material, a recrystallized silicon carbide sintered body with a bulk density of 2.35 g / cm 3 was prepared by the recrystallization sintering technique under an Ar atmosphere at 2350 °C and a pressure of 128000 Pa.
[0047] (2) The recrystallized silicon carbide sintered body with a bulk density of 2.35 g / cm 3 was ultrasonically cleaned in absolute ethanol for 15 min, dried at 150 °C for 15 min, and then placed on the sample stage as the matrix for use.
[0048] (3) When performing chemical vapor infiltration surface sealing on the recrystallized silicon carbide sintered body matrix, a gas mixture of methyltrichlorosilane and hydrogen was used as the source gas. The molar ratio of the source gas was MTS:H2 = 0.02, the flow rate of the source gas was 500 sccm, the flow rate of argon was 1500 sccm, the deposition temperature was 1050 °C, the pressure was 2 kPa, and the deposition time was 2 h.
[0049] Then, the coating was directly carried out.
[0050] (4) When coating after chemical vapor infiltration surface sealing on the recrystallized silicon carbide sintered body matrix, a gas mixture of methyltrichlorosilane and hydrogen was used as the source gas. The molar ratio of the source gas was MTS:H2 = 0.1, the flow rate of the source gas was 600 sccm, the flow rate of argon was 1500 sccm, the deposition temperature was 1400 °C, the pressure was 8 kPa, the deposition time was 2 h. After the deposition, it was cooled to room temperature in the furnace. Filling and sealing were achieved within a depth of 50 μm on the surface of the recrystallized silicon carbide matrix, and the thickness of the β-SiC coating was 90 μm.
[0051] In this embodiment, the sealing effect on the surface of the recrystallized silicon carbide sintered body matrix is good, the prepared coating has a dense structure, good bonding with the recrystallized silicon carbide sintered body matrix, and can provide excellent protection for the recrystallized silicon carbide sintered body matrix.
[0052] Example 3
[0053] In this embodiment, a chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors includes the following steps:
[0054] (1) Using high-purity silicon carbide powder (purity ≥ 99.99 wt%) as raw material, a recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm 3 was prepared by the recrystallization sintering technique under an Ar atmosphere at 2300 °C and a pressure of 130000 Pa;
[0055] (2) The recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm 3 was ultrasonically cleaned in absolute ethanol for 15 min, dried at 150 °C for 15 min, and then placed on a sample stage as a substrate for use;
[0056] (3) When chemically vapor infiltrating and surface sealing the recrystallized silicon carbide sintered body substrate, a gas mixture of methyltrichlorosilane and hydrogen was used as the raw material gas. The molar ratio of the raw material gas was MTS:H2 = 0.02, the flow rate of the raw material gas was 500 sccm, the flow rate of argon was 1500 sccm, the deposition temperature was 1050 °C, the pressure was 2 kPa, and the deposition time was 2 h.
[0057] Then, coating was directly carried out;
[0058] (4) When coating after chemically vapor infiltrating and surface sealing the recrystallized silicon carbide sintered body substrate, a gas mixture of methyltrichlorosilane and hydrogen was used as the raw material gas. The molar ratio of the raw material gas was MTS:H2 = 0.1, the flow rate of the raw material gas was 600 sccm, the flow rate of argon was 1500 sccm, the deposition temperature was 1400 °C, the pressure was 8 kPa, and the deposition time was 2 h. After the deposition was completed, it was cooled to room temperature in the furnace. Filling and sealing were achieved within a depth of 50 μm on the surface of the recrystallized silicon carbide substrate, and the thickness of the β-SiC coating was 60 μm.
[0059] In this embodiment, the surface sealing effect on the recrystallized silicon carbide sintered body substrate is good, the prepared coating has a dense structure, combines well with the recrystallized silicon carbide sintered body substrate, and can provide excellent protection for the recrystallized silicon carbide sintered body substrate.
[0060] As Figure 1 shown, the surface morphology diagram of the CVI surface sealing and coating of the recrystallized silicon carbide sintered body with a bulk density of 2.64 g / cm 3 in Example 1. It can be seen from Figure 1 that the surface of the prepared SiC coating is closely arranged and has almost no defects such as holes and cracks.
[0061] As Figure 2 shown, the recrystallized silicon carbide sintered body with a bulk density of 2.64 g / cm 3Cross-sectional morphology diagram of the CVI surface sealing and coating of recrystallized silicon carbide sintered body, from Figure 2 It can be seen that the CVI sealing effect is good, the prepared SiC coating has a dense structure and good interfacial bonding, and there are almost no defects such as pores and cracks.
[0062] As Figure 3 shown, the bulk density of Example 1 is 2.64 g / cm 3 XRD pattern of the CVI surface sealing and coating of recrystallized silicon carbide sintered body, from Figure 3 It can be seen that the diffraction peaks appearing in the figure are all diffraction peaks of β-SiC, and the (111) plane is the preferred orientation.
[0063] As Figure 4 shown, the bulk density of Example 1 is 2.64 g / cm 3 Surface roughness test curve of the CVI surface sealing and coating of recrystallized silicon carbide sintered body. The surface roughness Ra of this coating is measured to be 8.416 μm.
[0064] As Figure 5 shown, the bulk density of Example 2 is 2.35 g / cm 3 Surface morphology diagram of the CVI surface sealing and coating of recrystallized silicon carbide sintered body, from Figure 5 It can be seen that the prepared SiC coating surface is closely arranged and there are almost no defects such as pores and cracks.
[0065] As Figure 6 shown, the bulk density of Example 2 is 2.35 g / cm 3 Cross-sectional morphology diagram of the CVI surface sealing and coating of recrystallized silicon carbide sintered body, from Figure 6 It can be seen that the CVI sealing effect is good, the prepared SiC coating has a dense structure and good interfacial bonding, and there are almost no defects such as pores and cracks.
[0066] As Figure 7 shown, the bulk density of Example 2 is 2.35 g / cm 3 XRD pattern of the CVI surface sealing and coating of recrystallized silicon carbide sintered body, from Figure 7 It can be seen that the diffraction peaks appearing in the figure are all diffraction peaks of β-SiC, and the (111) plane is the preferred orientation.
[0067] As Figure 8 shown, the bulk density of Example 2 is 2.35 g / cm 3 Surface roughness test curve of the CVI surface sealing and coating of recrystallized silicon carbide sintered body. The surface roughness Ra of this coating is measured to be 9.707 μm.
[0068] As Figure 9As shown, the surface morphology diagram of the recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm³ in Example 3 after CVI surface sealing and coating is shown. 3 It can be seen from Figure 9 that the prepared SiC coating has a dense surface arrangement and almost no defects such as holes and cracks.
[0069] As Figure 10 shown, the cross-sectional morphology diagram of the recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm³ in Example 3 after CVI surface sealing and coating is shown. 3 It can be seen from Figure 10 that the CVI sealing effect is good, the prepared SiC coating has a dense structure, good interfacial bonding, and almost no defects such as holes and cracks.
[0070] As Figure 11 shown, the XRD pattern of the recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm³ in Example 3 after CVI surface sealing and coating is shown. 3 It can be seen from Figure 11 that the diffraction peaks appearing in the figure are all diffraction peaks of β-SiC, and the (111) plane is the preferred orientation.
[0071] As Figure 12 shown, the surface roughness test curve of the recrystallized silicon carbide sintered body with a bulk density of 2.01 g / cm³ in Example 3 after CVI surface sealing and coating is shown. The surface roughness Ra of this coating is measured to be 10.825 μm. 3
[0072] The results of the examples show that the present invention adopts a chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors. Through a staged CVI process, the surface of the recrystallized silicon carbide sintered body is sealed and coated. The sealing effect is good, the prepared coating has a dense structure, good bonding with the recrystallized silicon carbide sintered body matrix, and can play an excellent high-temperature protection role for the recrystallized silicon carbide sintered body matrix.
Claims
1. A chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors, characterized in that, Using recrystallized silicon carbide sintered bodies with different bulk densities as the substrate, and adopting a staged chemical vapor infiltration technique, with methyltrichlorosilane (MTS) gas as the raw material, the gas system introduced into the reaction chamber is selected as the MTS-H2-Ar system, including the following steps: (1) The recrystallized silicon carbide sintered body with a bulk density of 2.0 - 3.2 g / cm 3 was ultrasonically cleaned in absolute ethanol for 15 min, dried at 150 °C for 15 min, and then placed on the sample stage as the substrate for use; (2) When chemically vapor infiltrating and surface sealing the pores of the recrystallized silicon carbide sintered body substrate, the molar ratio of the raw material gases is MTS:H2 = 0.01 - 1, and argon is introduced. The deposition temperature is 1000 - 1400 °C, the pressure is 1 - 5 kPa, and the deposition time is 1 - 10 h, and then the coating is directly carried out; (3) When coating after chemically vapor infiltrating and surface sealing the pores of the recrystallized silicon carbide sintered body substrate, the molar ratio of the raw material gases is MTS:H2 = 0.01 - 1, and argon is introduced. The deposition temperature is 1200 - 1600 °C, the pressure is 5 - 10 kPa, and the deposition time is 1 - 10 h. After the deposition is completed, it is cooled to room temperature in the furnace.
2. The chemical vapor infiltration surface sealing method of a recrystallized silicon carbide sintered body for semiconductors according to claim 1, characterized in that, Preferably, in step (1), the bulk density of the recrystallized silicon carbide sintered body is 2.64 g / cm 3 .
3. A chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors according to claim 1, characterized in that, In step (2), the flow rate of the raw material gas is 100 - 10000 sccm, and the flow rate of argon is 100 - 10000 sccm.
4. A chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors according to claim 3, characterized in that, Preferably, in step (2), MTS:H2 = 0.02, the flow rate of the raw material gas is 500 sccm, the flow rate of argon is 1500 sccm, the deposition temperature is 1050 °C, the pressure is 2 kPa, and the deposition time is 2 h.
5. A chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors according to claim 1, characterized in that, In step (3), the flow rate of the raw material gas is 100 - 10000 sccm, and the flow rate of argon is 100 - 10000 sccm.
6. A chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors according to claim 5, characterized in that, Preferably, in step (3), MTS:H2 = 0.1, the flow rate of the raw material gas is 600 sccm, the flow rate of argon is 1500 sccm, the deposition temperature is 1400 °C, the pressure is 8 kPa, and the deposition time is 2 h.
7. A chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors according to claim 1, characterized in that, Filling and sealing the pores are achieved within a depth of 1 - 1000 μm on the surface of the recrystallized silicon carbide sintered body substrate, and the thickness of the SiC coating is 1 - 300 μm.
8. A chemical vapor infiltration surface sealing method for a recrystallized silicon carbide sintered body for semiconductors according to claim 7, characterized in that, Preferably, the filling depth on the surface of the recrystallized silicon carbide sintered body substrate is 10 - 500 μm, and the thickness of the SiC coating is 10 - 100 μm.