Silicon carbide coated graphite susceptor and preparation method and application thereof

Abstract

The present invention relates to a silicon carbide coated graphite susceptor and a preparation method and application thereof. The preparation method of the silicon carbide coated graphite susceptor comprises the following steps: placing a silicon-containing powder and a graphite susceptor in a reaction container, wherein the silicon-containing powder is selected from one of SiO powder and Si powder; vacuumizing the reaction container, introducing CO gas into the reaction container and heating it, and chemically reacting the CO gas with the silicon-containing gas formed by the volatilization of the silicon-containing powder to form a silicon carbide coating on the surface of the graphite susceptor, wherein in the step of introducing CO gas into the reaction container and heating it, the temperature of the reaction container is greater than 1400°C, and the flow rate of the CO gas is less than 800sccm. The preparation method of the silicon carbide coated graphite susceptor can well improve the compactness of the silicon carbide coating and the embedding depth in the graphite susceptor.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a silicon carbide coated graphite susceptor and a preparation method and application thereof. Background Art

[0002] With the rapid development of the light-emitting diode (LED) industry, the demand for LED epitaxial wafers has continued to increase. LED epitaxial wafers refer to single crystal thin films grown on substrate substrates. The quality of the silicon carbide coated graphite base that supports the substrate substrate directly affects the quality of LED epitaxial wafers. However, in traditional silicon carbide coated graphite bases, the bonding strength between the silicon carbide coating and the graphite base is poor, and the embedding depth in the graphite base is insufficient, which in turn affects the quality of LED epitaxial wafers. Summary of the invention

[0003] Based on this, it is necessary to provide a silicon carbide coated graphite base and a preparation method and application thereof to address the above problems. The preparation method of the silicon carbide coating can well control the embedding depth of the silicon carbide coating in the graphite base.

[0004] The present invention discloses a method for preparing a silicon carbide coated graphite susceptor, comprising the following steps:

[0005] Placing silicon-containing powder and a graphite base in a reaction container, wherein the silicon-containing powder comprises one of SiO powder and Si powder;

[0006] The reaction container is vacuumed, CO gas is introduced into the reaction container and heated, the CO gas reacts with the silicon-containing gas formed by volatilization of the silicon-containing powder to form a chemical vapor reaction, and a silicon carbide coating is formed on the surface of the graphite base, wherein in the step of introducing CO gas into the reaction container and heating, the temperature of the reaction container is greater than 1400° C., and the flow rate of the CO gas is less than 800 sccm.

[0007] In one embodiment, when the silicon-containing powder is SiO powder, in the step of introducing CO gas, the flow rate of the CO gas is greater than or equal to 600 sccm and less than 800 sccm;

[0008] When the silicon-containing powder is Si powder, in the step of introducing CO gas, the flow rate of the CO gas is greater than or equal to 400 sccm and less than 800 sccm.

[0009] In one embodiment, in the heating step, the heating rate is 5°C / min-10°C / min.

[0010] In one embodiment, in the heating step, the temperature of the reaction container is less than or equal to 1800°C and greater than 1400°C.

[0011] In one embodiment, in the step of placing the silicon-containing powder and the graphite susceptor in a reaction container, the mass ratio of the silicon-containing powder to the graphite susceptor is 1:2-1:20.

[0012] In one embodiment, in the step of performing a chemical vapor reaction, the mass of the silicon-containing powder is less than or equal to 1000 g.

[0013] In one embodiment, when the silicon-containing powder is SiO powder, in the step of performing a chemical vapor reaction, the reaction time is 3h-7h;

[0014] When the silicon-containing powder is Si powder, in the step of performing the chemical vapor reaction, the reaction time is 2h-5h.

[0015] A silicon carbide coated graphite susceptor is prepared by the above-mentioned method for preparing a silicon carbide coated graphite susceptor, comprising a graphite susceptor and a silicon carbide coating, wherein the silicon carbide coating is embedded in the graphite susceptor.

[0016] In one embodiment, when the silicon-containing powder is SiO powder, the embedding depth of the silicon carbide coating is greater than or equal to 200 μm;

[0017] When the silicon-containing powder is Si powder, the embedding depth of the silicon carbide coating is greater than or equal to 50 μm.

[0018] An application of the silicon carbide coated graphite base as described above in the preparation of light emitting diode epitaxial wafers.

[0019] In the preparation method of the silicon carbide coated graphite susceptor provided by the present invention, a silicon carbide coating is prepared with a single silicon-containing powder and CO gas as raw materials, the CO gas can not only prevent the silicon-containing gas from consuming carbon on the surface of the graphite susceptor, but the CO gas with a flow rate of less than 800 sccm can also reduce the concentration of the silicon-containing gas formed by the volatilization of the silicon-containing powder in the reaction container, reduce the reaction activity of the silicon-containing gas, slow down the reaction rate of the chemical vapor phase reaction, deepen the depth of the silicon-containing gas entering the graphite susceptor, and at the same time, the temperature of the reaction container is greater than 1400°C, which further deepens the depth of the silicon-containing gas entering the graphite susceptor, and finally well improves the embedding depth of the silicon carbide coating in the graphite susceptor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a scanning electron microscope image of the surface of the silicon carbide coated graphite base prepared in Example 1;

[0022] Figure 2 This is a scanning electron microscope image of the cross section of the silicon carbide coated graphite base prepared in Example 1;

[0023] Figure 3 This is the X-ray diffraction pattern of the silicon carbide coating prepared in Example 1;

[0024] Figure 4 This is a scanning electron microscope image of the cross section of the silicon carbide coated graphite base prepared in Example 6;

[0025] Figure 5 This is a scanning electron microscope image of the surface of the silicon carbide coated graphite base prepared in Example 6;

[0026] Figure 6 This is the energy spectrum analysis diagram of the silicon carbide coating prepared in Example 6. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the technical field of the terminology of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific implementation methods or embodiments and are not intended to limit the present invention.

[0029] The present invention provides a method for preparing a silicon carbide coated graphite susceptor, comprising the following steps:

[0030] S10, placing a silicon-containing powder and a graphite base in a reaction container, wherein the silicon-containing powder is selected from one of SiO powder and Si powder;

[0031] S20, evacuating the reaction container, introducing CO gas into the reaction container and heating it, the CO gas reacts with the silicon-containing gas formed by volatilization of the silicon-containing powder to form a silicon carbide coating on the surface of the graphite base, wherein in the step of introducing CO gas into the reaction container and heating it, the temperature of the reaction container is greater than 1400° C., and the flow rate of the CO gas is less than 800 sccm.

[0032] In the preparation method of the silicon carbide coated graphite susceptor provided by the present invention, a silicon carbide coating is prepared with a single silicon-containing powder and CO gas as raw materials, the CO gas can not only prevent the silicon-containing gas from consuming carbon on the surface of the graphite susceptor, but the CO gas with a flow rate of less than 800 sccm can also reduce the concentration of the silicon-containing gas formed by the volatilization of the silicon-containing powder in the reaction container, reduce the reaction activity of the silicon-containing gas, slow down the reaction rate of the chemical vapor phase reaction, deepen the depth of the silicon-containing gas entering the graphite susceptor, and at the same time, the temperature of the reaction container is greater than 1400°C, which further deepens the depth of the silicon-containing gas entering the graphite susceptor, and finally well improves the embedding depth of the silicon carbide coating in the graphite susceptor.

[0033] In step S10, in order to improve the bonding strength between the silicon carbide coating and the graphite base, in one embodiment, before placing the silicon-containing powder and the graphite base in a reaction vessel, the graphite base is pretreated. Preferably, the pretreatment step includes: first polishing the graphite base with sandpaper, then ultrasonically cleaning the graphite base, and finally drying it; preferably, the graphite base is polished to a roughness less than or equal to 1.6 μm.

[0034] In one embodiment, the graphite base is ultrasonically cleaned using water, and the ultrasonic cleaning time is 10 min-30 min, including but not limited to 10 min, 15 min, 20 min, 25 min or 30 min.

[0035] In one embodiment, in the step of placing the silicon-containing powder and the graphite base in a reaction container, the graphite base is located on the volatilization path of the silicon-containing powder; preferably, the step of placing the silicon-containing powder and the graphite base in the reaction container includes: first placing the silicon-containing powder on the bottom of a graphite crucible, placing the graphite base on the silicon-containing powder, and then placing the crucible containing the silicon-containing powder and the graphite base in the reaction container.

[0036] In order to accurately control the raw material composition of the chemical vapor reaction, thereby controlling the embedding depth of the silicon carbide coating in the graphite base, in one embodiment, the purity of the silicon-containing powder is greater than or equal to 99.99%.

[0037] In one embodiment, the mass ratio of the silicon-containing powder to the graphite base is 1:2-1:20, including but not limited to 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20, so as to ensure that there is a sufficient amount of silicon-containing gas in the reaction vessel.

[0038] In one embodiment, the mass of the silicon-containing powder is less than or equal to 1000g, including but not limited to 50g, 100g, 150g, 200g, 250g, 300g, 350g, 400g, 450g, 500g, 550g, 600g, 650g, 700g, 750g, 800g, 850g, 900g, 950g or 1000g, so as to ensure that there is a sufficient amount of silicon-containing gas in the reaction vessel and at the same time, reduce the concentration of the silicon-containing gas in the reaction vessel.

[0039] In step S20, during the heating process, the silicon-containing powder volatilizes to form a silicon-containing gas, which reacts with the CO gas in a chemical vapor phase to form a silicon carbide coating.

[0040] In order to better reduce the concentration of silicon-containing gas in the reaction container, the step of introducing CO gas into the reaction container and heating the reaction container includes first introducing CO gas into the reaction container and then increasing the temperature of the reaction container.

[0041] In one embodiment, the purity of the CO gas is greater than or equal to 99.99%, thereby ensuring the generation of a high-purity silicon carbide coating.

[0042] When the silicon-containing powder is SiO powder, in one embodiment, in the step of introducing CO gas, the flow rate of CO gas is greater than or equal to 600 sccm and less than 800 sccm, including but not limited to 600 sccm, 650 sccm, 700 sccm, 750 sccm or 790 sccm.

[0043] When the silicon-containing powder is Si powder, in one embodiment, in the step of introducing CO gas, the flow rate of CO gas is greater than or equal to 400 sccm and less than 800 sccm, including but not limited to 400 sccm, 500 sccm, 600 sccm, 650 sccm, 700 sccm, 750 sccm or 790 sccm.

[0044] In one embodiment, during the heating step, the temperature of the reaction container is controlled to be less than or equal to 1800° C., so as to slow down the reaction rate of the chemical vapor reaction, thereby further improving the uniformity and density of the silicon carbide coating and the embedding depth in the graphite base.

[0045] In one embodiment, in the heating step, the heating rate is 5°C / min-10°C / min, including but not limited to 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min or 10°C / min; so that the temperature of the reaction container rises steadily.

[0046] Under normal pressure (100 kPa), SiO powder exists in solid form at room temperature to 1700°C. The lower the pressure, the lower the volatilization temperature of SiO powder. In a vacuum environment, when the temperature reaches 1100°C-1200°C, SiO powder will begin to volatilize; at the same time, in a vacuum environment, there is no oxygen, and SiO will not react to form silicon dioxide. Therefore, when the silicon-containing powder is SiO powder, in the heating step, preferably, the temperature of the reaction container is less than or equal to 1800°C and greater than 1400°C, including but not limited to 1401°C, 1410°C, 1420°C, 1430°C, 1440°C, 1450°C, 1500°C, 1550°C, 1600°C, 1650°C, 1700°C, 1750°C, 1790°C or 1800°C.

[0047] In one embodiment, in the vacuum treatment step, the absolute pressure of the reaction container is less than or equal to 10Pa, including but not limited to 0Pa, 1Pa, 2Pa, 3Pa, 4Pa, 5Pa, 6Pa, 7Pa, 8Pa, 9Pa or 10Pa.

[0048] In one embodiment, when the silicon-containing powder is SiO powder, in the step of performing the chemical vapor reaction, the reaction time is 3 h-7 h, including but not limited to 3 h, 4 h, 5 h, 6 h or 7 h.

[0049] In one embodiment, when the silicon-containing powder is Si powder, in the step of performing the chemical vapor reaction, the reaction time is 2 h to 5 h, including but not limited to 2 h, 3 h, 4 h or 5 h.

[0050] The invention also provides a silicon carbide coated graphite base obtained by the preparation method, comprising a graphite base and a silicon carbide coating, wherein the silicon carbide coating is embedded in the graphite base.

[0051] In one embodiment, when the silicon-containing powder is SiO powder, the embedding depth of the silicon carbide coating is greater than or equal to 200 μm, including but not limited to 200 μm, 225 μm, 250 μm, 275 μm, 300 μm, 325 μm, 350 μm, 375 μm, 400 μm, 425 μm, 450 μm, 475 μm or 500 μm.

[0052] In one embodiment, when the silicon-containing powder is Si powder, the embedding depth of the silicon carbide coating is greater than or equal to 50μm, including but not limited to 50μm, 75μm, 100μm, 125μm, 150μm, 175μm, 200μm, 225μm, 250μm, 275μm, 300μm, 325μm, 350μm, 375μm, 400μm, 425μm, 450μm, 475μm or 500μm.

[0053] In one embodiment, the silicon carbide coating is mainly composed of β-SiC, and the thickness of the silicon carbide coating is 30 μm-100 μm, including but not limited to 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm.

[0054] The present invention also provides a use of the silicon carbide coated graphite base as described above in the preparation of light emitting diode epitaxial wafers.

[0055] The silicon carbide coated graphite base provided by the present invention has excellent uniformity, compactness and embedding depth in the graphite base. The silicon carbide coated graphite base is used to carry a substrate substrate for growing LED epitaxial wafers, which can greatly improve the quality of the LED epitaxial wafers.

[0056] Hereinafter, the silicon carbide coated graphite susceptor and its preparation method and application will be further described through the following specific embodiments.

[0057] Example 1

[0058] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0059] First, 100 g of SiO powder was placed on the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the SiO powder. The SiO powder and the pretreated graphite base were placed in a vacuum furnace.

[0060] The vacuum furnace was evacuated, and then the temperature was raised to 1600°C at a rate of 10°C / min. Then, 600sccm of CO gas was introduced to react with SiO gas formed by volatilization of SiO powder for chemical vapor phase reaction. The temperature was kept for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0061] Scanning electron microscopy analysis of the surface and cross section of the silicon carbide coated graphite susceptor was performed. Figure 1 and Figure 2 As shown. Figure 1 It can be seen that a dense silicon carbide coating is formed on the graphite base; Figure 2 It can be seen that the silicon carbide coating is embedded deeply in the graphite base, and it can be seen that the bonding force between the silicon carbide coating and the graphite substrate is high. Figure 3 is the X-ray diffraction pattern of silicon carbide coating. Figure 3 It can be seen that the silicon carbide coating is mainly composed of β-SiC phase.

[0062] Comparative Example 1

[0063] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0064] First, 100 g of SiO powder was placed on the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the SiO powder. The SiO powder and the pretreated graphite base were placed in a vacuum furnace.

[0065] The vacuum furnace was evacuated, and then the temperature was raised to 1600° C. at a rate of 10° C. / min and kept at that temperature for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0066] Comparative Example 2

[0067] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0068] First, a mixed powder of Si and SiO2 is placed at the bottom of a graphite crucible, and then 600 g of a pretreated graphite base is placed on the SiO powder. The SiO powder and the pretreated graphite base are placed in a vacuum furnace, wherein the molar ratio of Si to SiO2 is 1:1, and the total mass of Si and SiO2 is consistent with that of the SiO powder.

[0069] The vacuum furnace was evacuated, and then the temperature was raised to 1600°C at a rate of 10°C / min. Then, 600sccm of CO gas was introduced to react with SiO gas formed by volatilization of SiO powder for chemical vapor phase reaction. The temperature was kept for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0070] Comparative Example 3

[0071] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0072] First, 100 g of SiO powder was placed on the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the SiO powder. The SiO powder and the pretreated graphite base were placed in a vacuum furnace.

[0073] The vacuum furnace was evacuated, and then the temperature was raised to 1600°C at a rate of 10°C / min. Then, 1000sccm of CO gas was introduced to react with SiO gas formed by volatilization of SiO powder for chemical vapor phase reaction. The temperature was kept for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0074] Comparative Example 4

[0075] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0076] First, 100 g of SiO powder was placed on the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the SiO powder. The SiO powder and the pretreated graphite base were placed in a vacuum furnace.

[0077] The vacuum furnace was evacuated, and then the temperature was raised to 1600°C at a rate of 10°C / min. Then, 800sccm of CO gas was introduced to react with SiO gas formed by volatilization of SiO powder for chemical vapor phase reaction. The temperature was kept for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0078] Comparative Example 5

[0079] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0080] First, 100 g of SiO powder was placed on the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the SiO powder. The SiO powder and the pretreated graphite base were placed in a vacuum furnace.

[0081] The vacuum furnace was evacuated, and then the temperature was raised to 1300°C at a rate of 10°C / min. Then, 600sccm of CO gas was introduced to react with SiO gas formed by volatilization of SiO powder for chemical vapor phase reaction. The temperature was kept for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0082] Test Example 1

[0083] The embedding depth of the silicon carbide coatings prepared in Example 1 and Comparative Examples 1 to 5 in the graphite base was tested by the following test method and the test results are shown in Table 1.

[0084] Embedment depth in graphite susceptor: The embedment depth of silicon carbide coating in graphite susceptor was measured by scanning electron microscopy.

[0085] Density: Observe the surface with a scanning electron microscope and judge whether it is dense based on the exposure of graphite on the surface. The higher the density, the smaller the porosity, and vice versa.

[0086] Table 1

[0087]

[0088] Example 2

[0089] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0090] First, 100 g of SiO powder was placed on the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the SiO powder. The SiO powder and the pretreated graphite base were placed in a vacuum furnace.

[0091] The vacuum furnace was evacuated, and then the temperature was raised to 1900°C at a rate of 10°C / min. Then, 600sccm of CO gas was introduced to react with SiO gas formed by volatilization of SiO powder for chemical vapor phase reaction. The temperature was kept for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0092] Example 3

[0093] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0094] First, 100 g of SiO powder was placed on the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the SiO powder. The SiO powder and the pretreated graphite base were placed in a vacuum furnace.

[0095] The vacuum furnace was evacuated, and then the temperature was raised to 1800°C at a rate of 10°C / min. Then, 600sccm of CO gas was introduced to react with SiO gas formed by volatilization of SiO powder for chemical vapor phase reaction. The temperature was kept for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0096] Example 4

[0097] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0098] First, 200 g of SiO powder was placed on the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the SiO powder. The SiO powder and the pretreated graphite base were placed in a vacuum furnace.

[0099] The vacuum furnace was evacuated, and then the temperature was raised to 1600°C at a rate of 10°C / min. Then, 600sccm of CO gas was introduced to react with SiO gas formed by volatilization of SiO powder for chemical vapor phase reaction. The temperature was kept for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0100] Example 5

[0101] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 130° C. for 3 hours to obtain a pretreated graphite base.

[0102] First, 300 g of SiO powder was placed on the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the SiO powder. The SiO powder and the pretreated graphite base were placed in a vacuum furnace.

[0103] The vacuum furnace was evacuated, and then the temperature was raised to 1600°C at a rate of 10°C / min. Then, 600sccm of CO gas was introduced to react with SiO gas formed by volatilization of SiO powder for chemical vapor phase reaction. The temperature was kept for 4 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0104] Test Example 2

[0105] The embedding depth of the silicon carbide coatings prepared in Examples 2 to 5 in the graphite base was tested with reference to Test Example 1. The test results are shown in Table 2.

[0106] Table 2

[0107]

[0108] Example 6

[0109] The graphite base was polished with sandpaper, ultrasonically cleaned with pure water for 20 minutes, and then dried in an oven at 120° C. for 2 hours to obtain a pretreated graphite base.

[0110] First, 100 g of Si powder was placed at the bottom of a graphite crucible, and then 600 g of a pretreated graphite base was placed on the Si powder. The Si powder and the pretreated graphite base were placed in a vacuum furnace.

[0111] The vacuum furnace was evacuated and then heated to 1700°C at a rate of 10°C / min. Then, 400sccm of CO gas was introduced to react with Si gas formed by volatilization of Si powder for a chemical vapor phase reaction. The temperature was kept for 3 hours to form a silicon carbide coating on the surface of the graphite base, thereby obtaining a silicon carbide coated graphite base.

[0112] Scanning electron microscopy analysis of the cross section and surface of the silicon carbide coated graphite susceptor was performed. Figure 4 and Figure 5 As shown. Figure 4 It can be seen that the white part is the silicon carbide coating, which has an extremely deep embedding depth of more than 300μm. The silicon carbide coating has a high bonding force with the graphite base, and the silicon carbide coating has high strength and excellent thermal shock resistance. Figure 5 It can be seen that the surface of the SiC coating is continuous and the generated SiC grains are between 10 μm and 40 μm; Figure 6 This is the energy spectrum analysis diagram of silicon carbide coating. Figure 6 It can be seen that the silicon carbide coating is composed of two elements, Si and C.

[0113] Example 7

[0114] Example 7 is carried out in accordance with Example 6, except that the temperature is raised to 1800° C. at a rate of 10° C. / min; and the flow rate of CO gas is 600 sccm.

[0115] Comparative Example 6

[0116] Comparative Example 6 was carried out with reference to Example 6, except that the temperature of the reaction container was increased to 1400° C. at a heating rate of 10° C. / min.

[0117] Test Example 3

[0118] The embedding depth of the silicon carbide coatings prepared in Example 6 and Example 7 and Comparative Example 6 in the graphite base was tested with reference to Test Example 1. The test results are shown in Table 3.

[0119] Table 3

[0120]

[0121] Example 8

[0122] Example 8 was carried out with reference to Example 6, except that the flow rate of CO gas was 1000 sccm.

[0123] Example 9

[0124] Example 9 was carried out with reference to Example 6, except that the flow rate of CO gas was 700 sccm.

[0125] Example 10

[0126] Example 10 was carried out with reference to Example 6, except that the mass of Si powder was 200 g.

[0127] Embodiment 11

[0128] Example 11 was carried out with reference to Example 6, except that the mass of Si powder was 300 g.

[0129] Test Example 4

[0130] The embedding depth of the silicon carbide coatings prepared in Examples 8 to 11 in the graphite base was tested with reference to Test Example 1. The test results are shown in Table 4.

[0131] Table 4

[0132]

[0133] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0134] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a silicon carbide coated graphite susceptor, characterized in that: The following steps are involved: Placing silicon-containing powder and a graphite base in a reaction container, wherein the silicon-containing powder is selected from one of SiO powder and Si powder; The reaction container is evacuated, CO gas is introduced into the reaction container and heated, the CO gas reacts with the silicon-containing gas formed by the volatilization of the silicon-containing powder to form a silicon carbide coating on the surface of the graphite base, Wherein, in the step of introducing CO gas into the reaction container and heating it, the temperature of the reaction container is less than or equal to 1800°C and greater than or equal to 1600°C, and when the silicon-containing powder is SiO powder, in the step of introducing CO gas, the flow rate of the CO gas is greater than or equal to 600sccm and less than 800sccm; when the silicon-containing powder is Si powder, in the step of introducing CO gas, the flow rate of the CO gas is greater than or equal to 400sccm and less than 800sccm.

2. The method for preparing a silicon carbide coated graphite susceptor according to claim 1, characterized in that: In the heating step, the heating rate is 5°C / min-10°C / min.

3. The method for preparing a silicon carbide coated graphite susceptor according to claim 1 or 2, characterized in that: In the step of placing the silicon-containing powder and the graphite base in a reaction container, the mass ratio of the silicon-containing powder to the graphite base is 1:2-1:

20.

4. The method for preparing a silicon carbide coated graphite susceptor according to claim 3, characterized in that: In the step of performing a chemical vapor reaction, the mass of the silicon-containing powder is less than or equal to 1000 g.

5. The method for preparing a silicon carbide coated graphite susceptor according to claim 1 or 2, characterized in that: When the silicon-containing powder is SiO powder, in the step of performing chemical vapor reaction, the reaction time is 3h-7h; When the silicon-containing powder is Si powder, in the step of performing the chemical vapor reaction, the reaction time is 2h-5h.

6. A silicon carbide coated graphite susceptor, characterized in that: The silicon carbide coated graphite susceptor is prepared by the method for preparing the silicon carbide coated graphite susceptor according to any one of claims 1 to 5, comprising a graphite susceptor and a silicon carbide coating, wherein the silicon carbide coating is embedded in the graphite susceptor.

7. The silicon carbide coated graphite susceptor according to claim 6, characterized in that: When the silicon-containing powder is SiO powder, the embedding depth of the silicon carbide coating is greater than or equal to 200 μm; When the silicon-containing powder is Si powder, the embedding depth of the silicon carbide coating is greater than or equal to 50 μm.

8. Use of the silicon carbide coated graphite susceptor according to claim 6 or claim 7 in preparing light emitting diode epitaxial wafers.

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