Double-coating carrier plate in resistance-type heating MOCVD (Metal Organic Chemical Vapor Deposition) equipment and preparation method thereof

Abstract

The invention discloses a double-coating carrier disc in resistance-type heating MOCVD (Metal Organic Chemical Vapor Deposition) equipment and a preparation method of the double-coating carrier disc. The double-coating carrier disc comprises a graphite substrate, a silicon carbide coating on a heating surface of the graphite substrate and a tantalum carbide coating on a bearing substrate surface of the graphite substrate, and the gradient transition layer is arranged at the interface of the silicon carbide coating and the tantalum carbide coating. The method comprises the following steps: pretreating a graphite matrix; covering a non-deposition surface, and depositing a silicon carbide coating on the heating surface of the graphite substrate through pulse CVD (Chemical Vapor Deposition); turning over and covering the silicon carbide coating, and preparing a Ta-Si-C gradient transition layer on the bearing substrate surface of the graphite matrix; and finally, depositing a tantalum carbide coating on the bearing substrate surface of the graphite matrix. The silicon carbide coating, the tantalum carbide coating and the gradient transition layer are deposited on the graphite substrate, so that high thermal conductivity and high corrosion resistance are considered, thermal stress is effectively released, interface cracking is avoided, and the service life of the carrier plate in a corrosive atmosphere is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of CVD equipment processing technology, specifically to a double-coated carrier disk for a resistance-heated MOCVD equipment and its preparation method. Background Technology

[0002] MOCVD is a key piece of equipment for fabricating epitaxial wafers of III-V compound semiconductors such as gallium nitride and gallium arsenide. In resistance-heated MOCVD equipment, the carrier disk is used to support and heat the substrate, and its performance directly determines the temperature uniformity, crystal quality, and production efficiency of the epitaxial wafer.

[0003] Currently, MOCVD carriers mostly use high-purity graphite as the substrate, with a high-temperature resistant coating deposited on its surface to protect the graphite substrate from corrosion by the reaction atmosphere. Common coating materials include SiC and TaC. SiC coatings have excellent thermal conductivity (approximately 90-120 W / m·K), enabling rapid and uniform heating. However, under high-temperature corrosive atmospheres containing H2, NH3, and halogen compounds, they are prone to hydrogen corrosion and halogen erosion, generating volatile products such as SiCl4. This results in a rough coating surface, reduced thickness, and even peeling, leading to a short lifespan.

[0004] TaC coating has excellent high-temperature stability and corrosion resistance, and can work stably in highly corrosive atmospheres. However, its thermal conductivity is relatively low. If TaC coating is used alone, it will affect the heating efficiency and temperature uniformity of the carrier disk.

[0005] In order to balance thermal conductivity and corrosion resistance, the existing technology has attempted a SiC / TaC bilayer structure. However, due to the large difference in physical parameters (such as the coefficient of thermal expansion) between SiC and TaC, and the incompatibility of their chemical vapor deposition (CVD) process conditions (such as temperature and precursor), there are many challenges in actual preparation: (1) it is difficult to achieve selective growth and problems such as cross-deposition are easy to occur; (2) the interfacial bonding force between the two layers is weak, and the interface cracking or overall warping is easy to occur during thermal cycling due to thermal stress mismatch. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a double-coated carrier disk for resistance-heated MOCVD equipment and its preparation method. This method, through innovative double-sided coating structure design, interface gradient transition layer, and pulsed CVD combined with facet masking technology, solves problems such as poor interfacial adhesion and easy cross-contamination of the double coating, significantly improving the high-temperature stability, corrosion resistance, and service life of the carrier disk.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a double-coated carrier disk for a resistance-heated MOCVD apparatus, comprising: Graphite matrix; Silicon carbide coating formed on the heated surface of a graphite substrate; A tantalum carbide coating formed on the surface of a graphite substrate; And a gradient transition layer formed at the interface between the silicon carbide coating and the tantalum carbide coating.

[0008] The gradient transition layer is a Ta-Si-C gradient transition layer with a thickness of 0.5-5 μm; the silicon carbide coating and the tantalum carbide coating have the same thickness, and the thickness deviation is ±2 μm.

[0009] This invention also provides a method for preparing a double-coated carrier disk in a resistance-heated MOCVD apparatus. The method comprises the following steps: S100: Select a graphite matrix and pre-treat it to remove surface impurities and dust; S200. Cover the substrate surface of the graphite substrate, then place the graphite substrate in the first CVD deposition furnace, and introduce the first reaction gas source to deposit a silicon carbide coating on the heated surface of the graphite substrate. The first CVD deposition furnace is a silicon carbide coating deposition furnace, and the first reaction gas source is the gas source required for silicon carbide coating deposition. S300, The silicon carbide coating on the heated surface of the graphite substrate is masked, and a precursor slurry containing Ta, Si, and C is uniformly coated at a predetermined position on the substrate surface of the graphite substrate by brushing. The slurry is then fed into the second CVD deposition furnace so that the Ta, Si, and C in the precursor slurry diffuse into the interface with the silicon carbide coating, thereby forming a Ta-Si-C gradient transition layer. The second CVD deposition furnace is a tantalum carbide coating deposition furnace. S400. A second reaction gas source is introduced into the second CVD deposition furnace to deposit a tantalum carbide coating on the substrate surface of the graphite matrix. The second reaction gas source is the gas source required for the deposition of the tantalum carbide coating.

[0010] Further, step S100 specifically involves: first, selecting high-purity isostatic graphite as the graphite matrix, with a density of 1.75-2.1 g / cm³ and a surface roughness of 1-5 μm; then, ultrasonically cleaning the selected high-purity isostatic graphite in deionized water and anhydrous ethanol for 20-40 min in sequence to remove dust and impurities from the graphite matrix surface; finally, drying it in a vacuum drying oven at a temperature of 100-140℃ for 1-3 h to remove moisture from the graphite matrix surface.

[0011] Furthermore, it also includes step S100', placing the pretreated graphite substrate in an inert atmosphere for 5-10 minutes to improve the surface activity of the graphite substrate.

[0012] Further, in step S200, covering the substrate surface of the graphite substrate specifically involves: selecting a silicon carbide material or a cover plate with a silicon carbide coating that matches the substrate surface of the graphite substrate to cover the substrate surface of the graphite substrate, and continuously introducing inert gas into the covered area during the deposition of the silicon carbide coating on the heated surface of the graphite substrate to form a reverse airflow barrier, thereby preventing the permeation of the reactive gas.

[0013] Further, in step S200, depositing a silicon carbide coating on the heated surface of the graphite substrate specifically includes: placing the graphite substrate in a first CVD deposition furnace and introducing a first reaction gas source, and alternatingly performing deposition and purging through pulsed chemical vapor deposition to form a silicon carbide coating on the heated surface of the graphite substrate. The first reaction gas source is an MTS / H2 mixed gas or a SiCl4-CH4-H2-N2 mixed gas, the reaction pressure is controlled at 1-5 kPa, the reaction temperature is controlled at 1000-1600℃, and the reaction deposition time is 5-7 hours.

[0014] Further, step S300 specifically includes: S310. Use a tantalum carbide material or a ceramic cover plate with a tantalum carbide coating that matches the heating surface of the graphite substrate to cover the silicon carbide coating. S320. A precursor slurry containing Ta, Si, and C is uniformly coated at a predetermined position on the surface of a graphite substrate by brushing, thereby forming a pre-brushed transition coating. The thickness of the pre-brushed transition coating is controlled to be 1-2 μm. S330. The graphite substrate is fed into the second CVD deposition furnace and heated to 1100-1700℃. The temperature is maintained for 1-5 hours to form a Ta-Si-C gradient transition layer.

[0015] Further, in step S400, a pulsed CVD process is used to alternately deposit and purge in a second CVD deposition furnace to deposit a tantalum carbide coating on the substrate surface of the graphite matrix. The second reaction gas source is a TaCl5-CH4-H2-Ar mixed gas, with TaCl5 having a volume percentage of 4-6%, CH4 having a volume percentage of 8-12%, H2 having a volume percentage of 16-24%, and Ar having a volume percentage of 48-72%. The reaction temperature is controlled at 1000-1600℃, the reaction pressure is controlled at 1-10kPa, and the reaction deposition time is 10-14 hours.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: (1) This invention achieves a perfect combination of rapid heating and strong corrosion resistance of the double-coated carrier disk by setting a high thermal conductivity silicon carbide coating on the heating surface of the graphite substrate and setting a high corrosion resistant tantalum carbide coating on the substrate surface of the graphite substrate, thus solving the problem of insufficient performance of a single material.

[0017] (2) The present invention forms a Ta-Si-C gradient transition layer at the interface between the silicon carbide coating and the tantalum carbide coating. The gradient transition layer effectively relieves the thermal stress caused by the difference in thermal expansion coefficient between the silicon carbide coating and the tantalum carbide coating through the gradual change of elements and lattice, fundamentally preventing interface cracking and coating peeling, and greatly improving the structural stability of the double-coated carrier disk under thermal cycling.

[0018] (3) The present invention employs faceted masking and inert gas flow barrier, and combines pulsed CVD process to ensure that silicon carbide coating and tantalum carbide coating are precisely deposited on their respective functional surfaces, avoiding cross-contamination and achieving high uniformity of coating thickness and clear interface boundary.

[0019] (4) This invention improves the deposition rate and gas utilization rate by combining independent deposition in separate furnaces with pulsed CVD, reduces the cleaning time and energy consumption, shortens the overall preparation cycle by 30%-40%, and effectively reduces production costs. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the double-coated carrier disk structure in the resistance-heated MOCVD equipment of the present invention; Figure 2 This is a flowchart of the method for preparing a double-coated carrier disk in a resistance-heated MOCVD device according to the present invention; Figure 3 This is an image showing the effect of the silicon carbide coating in the double-coated carrier disk prepared in Example 1; Figure 4 This is an image showing the effect of the tantalum carbide coating in the double-coated carrier disk prepared in Example 1.

[0022] In the figure: 1. Graphite substrate, 2. Silicon carbide coating, 3. Tantalum carbide coating, 4. Gradient transition layer. Detailed Implementation

[0023] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way.

[0024] like Figure 1 As shown, the present invention provides a double-coated carrier disk in a resistance-heated MOCVD apparatus, comprising: Graphite matrix 1; A silicon carbide coating 2 is formed on the heating surface of the graphite substrate 1; A tantalum carbide coating 3 is formed on the substrate surface of the graphite matrix 1; And a gradient transition layer 4 formed at the interface between the silicon carbide coating 2 and the tantalum carbide coating 3.

[0025] In the above embodiments, the gradient transition layer 4 is a Ta-Si-C gradient transition layer with a thickness of 0.5-5μm; the silicon carbide coating 2 and the tantalum carbide coating 3 have the same thickness, and the thickness deviation is ±2μm.

[0026] In the above embodiments, by depositing a highly thermally conductive silicon carbide coating 2 on the heating surface of the graphite substrate 1 and a highly corrosion-resistant tantalum carbide coating 3 on the substrate bearing surface of the graphite substrate 1, a perfect combination of rapid heating and strong corrosion resistance is achieved in the double-coated carrier disk. Simultaneously, a Ta-Si-C gradient transition layer 4 is deposited at the interface between the silicon carbide coating 2 and the tantalum carbide coating 3, effectively mitigating the thermal stress caused by the difference in thermal expansion coefficients between the two coatings, fundamentally preventing interface cracking and coating peeling, and significantly improving the structural stability of the double-coated carrier disk under thermal cycling. Therefore, the double-coated carrier disk provided by this invention has the characteristics of high thermal conductivity, corrosion resistance, and structural stability, effectively solving the technical problems existing in single-material carrier disks in the prior art.

[0027] like Figure 2 As shown, the present invention also provides a method for preparing a double-coated carrier disk in a resistance-heated MOCVD device. The method, used to prepare the aforementioned double-coated carrier disk in a resistance-heated MOCVD device, includes the following steps: S100. Select graphite matrix 1 and pre-treat it to remove surface impurities and dust; The specific steps are as follows: First, high-purity isostatic graphite is selected as the graphite matrix 1, with a density of 1.75-2.1 g / cm³. 3 The surface roughness is 1-5μm; then the selected high-purity isostatic graphite is ultrasonically cleaned in deionized water and anhydrous ethanol for 20-40 min to remove dust and impurities from the surface of the graphite substrate 1; finally, it is dried in a vacuum drying oven at 100-140℃ for 1-3 h to remove moisture from the surface of the graphite substrate 1. To further ensure that the graphite substrate 1 is free of impurities and moisture, the pretreated graphite substrate 1 can be pre-fired in an inert atmosphere for 5-10 minutes. Pre-firing not only removes impurities and moisture from the surface of the graphite substrate 1, but also improves the surface activity of the graphite substrate 1, thereby promoting the bonding between the graphite substrate 1 and the coating. The inert gas can be nitrogen, argon or helium.

[0028] S200. Cover the substrate surface of the graphite substrate, then place the graphite substrate in the first CVD deposition furnace, and introduce the first reaction gas source to deposit a silicon carbide coating on the heated surface of the graphite substrate. The first CVD deposition furnace is a silicon carbide coating deposition furnace, and the first reaction gas source is the gas source required for silicon carbide coating deposition. In this step, firstly, a silicon carbide material or a masking plate with a silicon carbide coating that matches the substrate surface of the graphite substrate 1 is selected to cover the substrate surface of the graphite substrate 1. During the deposition of the silicon carbide coating on the heated surface of the graphite substrate 1, an inert gas is continuously introduced into the masked area to form a reverse airflow barrier, thereby preventing the permeation of the reactive gas. Then, the graphite substrate 1 is placed in the first CVD deposition furnace and a first reactive gas source is introduced. Deposition and purging are performed alternately through pulsed chemical vapor deposition, thereby forming a silicon carbide coating 2 on the heated surface of the graphite substrate 1. The first reactive gas source is an MTS / H2 mixed gas or a SiCl4-CH4-H2-N2 mixed gas. The reaction pressure is controlled at 1-5 kPa, the reaction temperature is controlled at 1000-1600℃, and the reaction deposition time is 5-7 hours.

[0029] S300, The silicon carbide coating 2 on the heated surface of the graphite substrate 1 is covered, and a precursor slurry containing Ta, Si, and C is uniformly coated at a predetermined position on the substrate surface of the graphite substrate 1 by brushing. The slurry is then fed into a second CVD deposition furnace so that the Ta, Si, and C in the precursor slurry diffuse into the interface with the silicon carbide coating 2, thereby forming a Ta-Si-C gradient transition layer 4. The second CVD deposition furnace is a tantalum carbide coating deposition furnace. This step specifically includes: S310. Use a tantalum carbide material or a ceramic cover plate with a tantalum carbide coating that matches the heating surface of the graphite substrate 1 to cover the silicon carbide coating 3. S320. A precursor slurry containing Ta, Si, and C is uniformly coated at a predetermined position on the substrate surface of the graphite substrate 1 by brushing, thereby forming a pre-brushed transition coating. The thickness of the pre-brushed transition coating is controlled to be 1-2 μm. S330. The graphite substrate 1 is fed into the second CVD deposition furnace and heated to 1100-1700℃. After holding at this temperature for 1-5 hours, a Ta-Si-C gradient transition layer 4 can be formed.

[0030] S400. A second reaction gas source is introduced into the second CVD deposition furnace to deposit a tantalum carbide coating on the substrate surface of the graphite matrix. The second reaction gas source is the gas source required for the deposition of the tantalum carbide coating.

[0031] Specifically, this step involves alternating deposition and purging in a second CVD furnace using a pulsed CVD process to deposit a tantalum carbide coating 3 on the substrate surface of the graphite substrate 1. The second reaction gas source is a TaCl5-CH4-H2-Ar mixed gas, with TaCl5 accounting for 4-6% by volume, CH4 accounting for 8-12% by volume, H2 accounting for 16-24% by volume, and Ar accounting for 48-72% by volume. The reaction temperature is controlled at 1000-1600℃, the reaction pressure is controlled at 1-10kPa, and the reaction deposition time is 10-14 hours.

[0032] In the above embodiments, the use of a faceted masking method effectively avoids cross-deposition and contamination during the deposition of silicon carbide coating 2 and tantalum carbide coating 3. At the same time, by using a pulsed CVD process, inert gas is used to purge at each deposition stage to ensure that silicon carbide coating 2 and tantalum carbide coating 3 are deposited only on their respective functional surfaces, reducing problems such as uneven coating thickness and interface defects. Moreover, the pulsed deposition process also effectively controls the deposition rate and thickness, making the thickness of silicon carbide coating 2 and tantalum carbide coating 3 consistent, avoiding stress concentration and interface delamination caused by uneven thickness. Therefore, this invention achieves a perfect combination of rapid heating and strong corrosion resistance in the dual-coated carrier disk by depositing a highly thermally conductive silicon carbide coating 2 on the heating surface of the graphite substrate 1 and a highly corrosion-resistant tantalum carbide coating 3 on the substrate surface of the graphite substrate 1. The Ta-Si-C gradient transition layer 4 formed at the interface between the silicon carbide coating 2 and the tantalum carbide coating 3 effectively alleviates the thermal stress caused by the difference in the coefficient of thermal expansion between the silicon carbide coating 2 and the tantalum carbide coating 3, fundamentally preventing interface cracking and coating peeling, and significantly improving the structural stability of the dual-coated carrier disk under thermal cycling.

[0033] To further illustrate the working principle and technical effects of the present invention, the following example uses the method for preparing a double-coated carrier disk in a resistance-heated MOCVD device provided by the present invention, and compares the performance of the prepared double-coated carrier disk with that of a carrier disk prepared with existing silicon carbide coating.

[0034] Example 1 The double-coated carrier disk is prepared using the method for preparing a double-coated carrier disk in a resistance-heated MOCVD device provided by this invention. The specific process is as follows: 1) High-purity isostatic graphite with a density of 1.85 g / cm³ and a surface roughness of 3 μm was selected as graphite matrix 1. It was ultrasonically cleaned in deionized water and anhydrous ethanol for 30 min in sequence, and then dried in a vacuum drying oven at 120℃ for 2 h to ensure that there was no moisture on the surface of graphite matrix 1. 2) Select a silicon carbide material or a cover plate with a silicon carbide coating that matches the substrate surface of the graphite substrate 1 to cover the substrate surface of the graphite substrate 1. The edge of the cover plate is provided with a stepped micro-gap sealing structure (gap ≤ 0.1 mm). Then, place the graphite substrate 1 in the first CVD deposition furnace and introduce the first reaction gas source. The deposition and purging are carried out alternately by pulsed chemical vapor deposition to form a silicon carbide coating on the heated surface of the graphite substrate 1. The first reaction gas source is an MTS / H2 mixed gas or a SiCl4-CH4-H2-N2 mixed gas. The reaction pressure is controlled at 3 kPa, the reaction temperature is controlled at 1300℃, and the reaction deposition time is 6 hours. During the deposition of the silicon carbide coating, inert gas needs to be continuously introduced into the covered area to form a reverse airflow barrier to prevent the reaction gas from penetrating into the substrate surface of the graphite substrate 1. 3) Select a tantalum carbide material or a ceramic cover plate with a tantalum carbide coating that matches the heating surface of the graphite substrate 2 to cover the silicon carbide coating, and uniformly coat a precursor slurry containing Ta, Si, and C at a predetermined position on the substrate surface of the graphite substrate 1 by brushing. The thickness of the precursor slurry is controlled to be 1.5 μm. Then, the graphite substrate 1 is sent into the second CVD deposition furnace and heated to 1400℃ and held for 3 hours to form a Ta-Si-C gradient transition layer 4 at the predetermined position. The predetermined position refers to the interface between the silicon carbide coating 2 and the tantalum carbide coating 3. 4) A second reaction gas source is introduced into the second CVD deposition furnace. A pulsed CVD process is used to alternately deposit and purge in the second CVD deposition furnace, thereby depositing a tantalum carbide coating 3 on the substrate surface of the graphite substrate 1. The second reaction gas source is a TaCl5-CH4-H2-Ar mixed gas, with TaCl5 accounting for 5% by volume, CH4 for 10% by volume, H2 for 20% by volume, and Ar for 65% by volume. The reaction temperature is controlled at 1300℃, the reaction pressure at 5 kPa, and the deposition time at 12 hours, thus obtaining a double-coated carrier disk. Figure 3 and Figure 4 As shown, Figure 3 The silicon carbide coating in this dual-coated carrier is shown. Figure 4 The tantalum carbide coating in the dual-coated carrier is shown.

[0035] Example 2 The double-coated carrier disk is prepared using the method for preparing a double-coated carrier disk in a resistance-heated MOCVD device provided by this invention. The specific process is as follows: 1) High-purity isostatic graphite with a density of 1.75 g / cm³ and a surface roughness of 1 μm was selected as graphite matrix 1. It was ultrasonically cleaned in deionized water and anhydrous ethanol for 20 min in sequence, and then dried in a vacuum drying oven at 100℃ for 3 h to ensure that there was no moisture on the surface of graphite matrix 1. 2) Select a silicon carbide material or a cover plate with a silicon carbide coating that matches the substrate surface of the graphite substrate 1 to cover the substrate surface of the graphite substrate 1. The edge of the cover plate is provided with a stepped micro-gap sealing structure (gap ≤ 0.1 mm). Then, place the graphite substrate 1 in the first CVD deposition furnace and introduce the first reaction gas source. The deposition and purging are performed alternately by pulsed chemical vapor deposition to form a silicon carbide coating on the heated surface of the graphite substrate 1. The first reaction gas source is an MTS / H2 mixed gas or a SiCl4-CH4-H2-N2 mixed gas. The reaction pressure is controlled at 1 kPa, the reaction temperature is controlled at 1000℃, and the reaction deposition time is 7 hours. During the deposition of the silicon carbide coating, inert gas needs to be continuously introduced into the covered area to form a reverse airflow barrier to prevent the reaction gas from penetrating into the substrate surface of the graphite substrate 1. 3) Select a tantalum carbide material or a ceramic cover plate with a tantalum carbide coating that matches the heating surface of the graphite substrate 2 to cover the silicon carbide coating, and uniformly coat a precursor slurry containing Ta, Si, and C at a predetermined position on the substrate surface of the graphite substrate 1 by brushing. The thickness of the precursor slurry is controlled to be 1 μm. Then, the graphite substrate 1 is sent into the second CVD deposition furnace and heated to 1100℃ and held for 1 hour to form a Ta-Si-C gradient transition layer 4 at the predetermined position. The predetermined position refers to the interface between the silicon carbide coating 2 and the tantalum carbide coating 3. 4) A second reaction gas source is introduced into the second CVD deposition furnace. A pulsed CVD process is used to alternately deposit and purge in the second CVD deposition furnace, thereby depositing a tantalum carbide coating 3 on the substrate surface of the graphite substrate 1. The second reaction gas source is a TaCl5-CH4-H2-Ar mixed gas, with a volume percentage of 4% for TaCl5, 8% for CH4, 16% for H2, and 72% for Ar. The reaction temperature is controlled at 1000℃, the reaction pressure is controlled at 1kPa, and the reaction deposition time is 14 hours, thus obtaining a double-coated carrier disk.

[0036] Example 3 The double-coated carrier disk is prepared using the method for preparing a double-coated carrier disk in a resistance-heated MOCVD device provided by this invention. The specific process is as follows: 1) High-purity isostatic graphite with a density of 2.1 g / cm³ and a surface roughness of 5 μm was selected as graphite matrix 1. It was ultrasonically cleaned in deionized water and anhydrous ethanol for 40 min in sequence, and then dried in a vacuum drying oven at 140℃ for 1 h to ensure that there was no moisture on the surface of graphite matrix 1. 2) Select a silicon carbide material or a cover plate with a silicon carbide coating that matches the substrate surface of the graphite substrate 1 to cover the substrate surface of the graphite substrate 1. The edge of the cover plate is provided with a stepped micro-gap sealing structure (gap ≤ 0.1 mm). Then, place the graphite substrate 1 in the first CVD deposition furnace and introduce the first reaction gas source. The deposition and purging are performed alternately by pulsed chemical vapor deposition to form a silicon carbide coating on the heated surface of the graphite substrate 1. The first reaction gas source is an MTS / H2 mixed gas or a SiCl4-CH4-H2-N2 mixed gas. The reaction pressure is controlled at 5 kPa, the reaction temperature is controlled at 1600℃, and the reaction deposition time is 5 hours. During the deposition of the silicon carbide coating, inert gas needs to be continuously introduced into the covered area to form a reverse airflow barrier, thereby preventing the reaction gas from penetrating into the substrate surface of the graphite substrate 1. 3) Select a tantalum carbide material or a ceramic cover plate with a tantalum carbide coating that matches the heating surface of the graphite substrate 2 to cover the silicon carbide coating, and uniformly coat a precursor slurry containing Ta, Si, and C at a predetermined position on the substrate surface of the graphite substrate 1 by brushing. The thickness of the precursor slurry is controlled to be 2 μm. Then, the graphite substrate 1 is sent into the second CVD deposition furnace and heated to 1700℃ and held for 5 hours to form a Ta-Si-C gradient transition layer 4 at the predetermined position. The predetermined position refers to the interface between the silicon carbide coating 2 and the tantalum carbide coating 3. 4) A second reaction gas source is introduced into the second CVD deposition furnace. A pulsed CVD process is used to alternately deposit and purge in the second CVD deposition furnace, thereby depositing a tantalum carbide coating 3 on the substrate surface of the graphite substrate 1. The second reaction gas source is a TaCl5-CH4-H2-Ar mixed gas, with a volume percentage of 6% for TaCl5, 12% for CH4, 24% for H2, and 58% for Ar. The reaction temperature is controlled at 1600℃, the reaction pressure is controlled at 10kPa, and the reaction deposition time is 10 hours, thus obtaining a double-coated carrier disk.

[0037] Comparative Example 1 Select the same graphite substrate 1 as in Example 1, and deposit a silicon carbide coating on the graphite substrate 1 to obtain a carrier disk with a single silicon carbide coating.

[0038] The carrier disks prepared in Examples 1-3 and Comparative Example 1 were placed in a corrosive atmosphere containing H2, Cl2 and NH3 at a temperature of 1850℃ for 500h and 1000h respectively, and the test results are shown in Table 1.

[0039] Table 1. Test results of Examples 1-3 and Comparative Example 1 <![CDATA[Continuously operate for 500 h in a corrosive atmosphere at a temperature of 1850 °C and containing H2, Cl2, and NH3]]> <![CDATA[Operate continuously for 1000 h in a corrosive atmosphere at a temperature of 1850 °C and containing H2, Cl2 and NH3]]> Example 1 The carrier disk surface is intact, with no visible corrosion, peeling, or cracks. The epitaxial wafer temperature uniformity is better than ±1.5℃. The carrier disk surface is intact, with no visible corrosion, peeling, or cracks. The epitaxial wafer temperature uniformity is better than ±1.5℃. Example 2 The carrier disk surface is intact, with no visible corrosion, peeling, or cracks. The epitaxial wafer temperature uniformity is better than ±1.5℃. The carrier disk surface is intact, with no visible corrosion, peeling, or cracks. The epitaxial wafer temperature uniformity is better than ±1.5℃. Example 3 The carrier disk surface is intact, with no visible corrosion, peeling, or cracks. The epitaxial wafer temperature uniformity is better than ±1.5℃. The carrier disk surface is intact, with no visible corrosion, peeling, or cracks. The epitaxial wafer temperature uniformity is better than ±1.5℃. Comparative Example 1 The carrier disk surface showed obvious haze, increased roughness, and slight peeling at the edges. The temperature uniformity of the epitaxial wafer decreased to more than ±3.5℃. Significant fogging and a substantial increase in roughness were observed on the carrier disk surface, with large-scale peeling at the edges. The temperature uniformity of the epitaxial wafer decreased to more than ±5.5℃. As shown in Table 1, the double-coated carrier disks prepared in Examples 1-3, after continuous operation at 1850℃ in a corrosive atmosphere containing H2, Cl2, and NH3 for 500h and 1000h respectively, showed intact surfaces with no visible corrosion, peeling, or cracks, and the temperature measurement showed that the epitaxial wafer temperature uniformity was better than ±1.5℃. In contrast, the silicon carbide coated carrier disk prepared in Comparative Example 1, after continuous operation at 1850℃ in a corrosive atmosphere containing H2, Cl2, and NH3 for 500h, showed obvious surface fogging, increased roughness, and slight peeling at the edges. The temperature measurement showed that the epitaxial wafer temperature uniformity decreased to more than ±3.5℃. After continuous operation at 1850℃ in a corrosive atmosphere containing H2, Cl2, and NH3 for 1000h, the silicon carbide coated carrier disk showed significant surface fogging, a substantial increase in roughness, large-area peeling at the edges, and the epitaxial wafer temperature uniformity decreased to more than ±5.5℃. Therefore, it can be seen that the single silicon carbide coated carrier disk under high temperature and corrosive atmosphere undergoes hydrogen corrosion and / or halogen erosion. That is, the corrosive gas reacts with the silicon carbide coating to generate volatile SiCl4 and other products, resulting in increased surface roughness of the silicon carbide coating, peeling at the edges, and a decrease in the temperature uniformity of the epitaxial wafer. Moreover, the corrosion phenomenon becomes more and more serious with the increase of operating time. In contrast, the double-coated carrier disk prepared in Examples 1-3 places a highly thermally conductive silicon carbide coating on the heating surface of the graphite substrate and a highly corrosion-resistant tantalum carbide coating on the graphite substrate support. The substrate surface achieves a perfect combination of rapid heating and strong corrosion resistance for the double-coated carrier disk, ensuring temperature uniformity of the epitaxial wafer while preventing erosion of the carrier disk by high-temperature corrosive gases. Simultaneously, a Ta-Si-C gradient transition layer is formed at the interface between the silicon carbide and tantalum carbide coatings. This gradient transition layer, through elemental and lattice gradients, effectively mitigates the thermal stress caused by the difference in thermal expansion coefficients between the silicon carbide and tantalum carbide coatings, fundamentally preventing interface cracking and coating peeling, and significantly improving the structural stability of the double-coated carrier disk under thermal cycling. Therefore, the double-coated carrier disk and its preparation method in the resistance-heated MOCVD equipment provided by this invention can significantly improve the interfacial adhesion and corrosion resistance of the carrier disk, solving the technical problems existing in the single-coated carrier disk of the prior art.

[0040] The foregoing has provided a detailed description of a double-coated carrier disk in a resistance-heated MOCVD apparatus and its preparation method. Specific examples have been used to illustrate the principles and implementation methods of this application; the descriptions of the embodiments above are merely for the purpose of helping to understand the core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A double-coated susceptor in a resistively heated MOCVD apparatus, characterized in that, The method comprises the following steps: a graphite substrate; a silicon carbide coating formed on a heating surface of the graphite substrate; a tantalum carbide coating formed on a substrate bearing surface of the graphite substrate; and a gradient transition layer formed at an interface between the silicon carbide coating and the tantalum carbide coating.

2. The dual-coated susceptor in a resistive-heating MOCVD apparatus according to claim 1, wherein, The gradient transition layer is a Ta-Si-C gradient transition layer with a thickness of 0.5-5 μm.

3. The dual-coated susceptor for resistive heating MOCVD apparatus of claim 2, wherein, The thickness of the silicon carbide coating and the tantalum carbide coating is consistent, and the thickness deviation is ±2 μm.

4. A method for preparing a double-coated susceptor in a resistive heating MOCVD apparatus, characterized by, The method for preparing the double-coating carrier disc in the resistive heating MOCVD device according to any one of claims 1-3 comprises the following steps: S100, selecting a graphite substrate and pre-treating the graphite substrate to remove surface impurities and dust; S200, covering the substrate bearing surface of the graphite substrate, and then placing the graphite substrate in a first CVD deposition furnace and introducing a first reaction gas source to deposit a silicon carbide coating on the heating surface of the graphite substrate, wherein the first CVD deposition furnace is a silicon carbide coating deposition furnace, and the first reaction gas source is a gas source required for silicon carbide coating deposition; S300, covering the silicon carbide coating on the heating surface of the graphite substrate, and uniformly coating a precursor slurry containing Ta, Si and C at a predetermined position on the substrate bearing surface of the graphite substrate by a brushing method, and then introducing the precursor slurry into a second CVD deposition furnace to make Ta, Si and C in the precursor slurry diffuse and react with the interface of the silicon carbide coating, thereby forming a Ta-Si-C gradient transition layer, wherein the second CVD deposition furnace is a tantalum carbide coating deposition furnace; S400, introducing a second reaction gas source into the second CVD deposition furnace to deposit a tantalum carbide coating on the substrate bearing surface of the graphite substrate, wherein the second reaction gas source is a gas source required for tantalum carbide coating deposition.

5. The method of claim 4, wherein the method further comprises: depositing a second coating layer on the first coating layer. The step S100 specifically comprises the following steps: first, selecting high-purity isostatic pressing graphite as the graphite substrate, and the density of the graphite substrate is 1.75-2.1 g / cm³, and the surface roughness of the graphite substrate is 1-5 μm; then ultrasonic cleaning the selected high-purity isostatic pressing graphite in deionized water and anhydrous ethanol for 20-40 min to remove dust and impurities on the surface of the graphite substrate; and finally, drying the graphite substrate in a vacuum drying box at a temperature of 100-140 ℃ for 1-3 h to remove moisture on the surface of the graphite substrate.

6. The method of claim 5, wherein the method further comprises: The step S100' further comprises the following step: pre-burning the pre-treated graphite substrate in an inert atmosphere for 5-10 min to improve the surface activity of the graphite substrate.

7. The method of claim 6, wherein the method further comprises: depositing a second coating layer on the first coating layer. In the step S200, the substrate bearing surface of the graphite substrate is covered with a covering plate made of silicon carbide or having a silicon carbide coating, and inert gas is continuously introduced into the covering area to form a reverse airflow barrier during the deposition of the silicon carbide coating on the heating surface of the graphite substrate, thereby preventing the penetration of the reaction gas.

8. The method of claim 7, wherein the method further comprises: depositing a second coating layer on the first coating layer. The step S200 specifically comprises: placing the graphite matrix in a first CVD deposition furnace and inputting a first reaction gas source, alternately performing deposition and purging by pulse chemical vapor deposition, and then forming a silicon carbide coating on the heated surface of the graphite matrix, wherein the first reaction gas source is MTS / H2 mixed gas or SiCl4-CH4-H2-N2 mixed gas, the reaction pressure is controlled to be 1-5 kPa, the reaction temperature is controlled to be 1000-1600 ℃, and the reaction deposition time is 5-7 hours.

9. The method of claim 8, wherein the method further comprises: depositing a second coating layer on the first coating layer. The step S300 specifically comprises: S310, covering the silicon carbide coating with a tantalum carbide material or a ceramic cover plate with a tantalum carbide coating matched with the heated surface of the graphite matrix; S320, uniformly coating a precursor slurry containing Ta, Si and C on the preset position of the substrate surface of the graphite matrix by a brushing method, and then forming a pre-brushed transition coating, and the thickness of the pre-brushed transition coating is controlled to be 1-2 μm; S330, placing the graphite matrix into a second CVD deposition furnace and heating to 1100-1700 ℃, and holding for 1-5 hours, so as to form a Ta-Si-C gradient transition layer.

10. The method of claim 9, wherein the method further comprises: depositing a second coating layer on the first coating layer. In step S400, a pulsed CVD process is used to alternately deposit and purge in a second CVD deposition furnace, thereby depositing a tantalum carbide coating on the substrate surface of the graphite matrix. The second reaction gas source is... Mixed gas, The volume percentage is 4-6%. The volume percentage is 8-12%. The volume percentage of Mg is 16-24%, the volume percentage of Ar is 48-72%, the reaction temperature is controlled at 1000-1600℃, the reaction pressure is controlled at 1-10kPa, and the reaction deposition time is 10-14 hours.

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