Material defect repairing hot filament CVD device and operation method thereof

Abstract

The invention discloses a material defect repairing hot filament CVD (chemical vapor deposition) device and an operation method thereof. The device consists of a quartz glass cover and a base, and comprises a hot wire, a base material clamping mechanism up-down actuating shaft, an air inlet / outlet pipeline, an electrode, a vacuum degree meter, an infrared thermometer and a high-temperature observation window, so that a controllable vacuum chamber is formed. During operation, the quartz glass cover is opened, the hot wire and a base material sample are arranged, the vacuum pump evacuates the chamber after sealing, then the hot wire is heated, reactive gas is introduced, and uniform growth of sediments is realized by adjusting the actuating shaft. After the deposition process is finished, the reaction gas can be replaced for continuous deposition until the deposition is finished, inert gas cooling is switched to, and finally the quartz glass cover is opened to take out the sample. By accurately controlling the deposition conditions, the quality of the thin film and the nanowire is improved, the operation speed is increased, and the method is suitable for defect repair of the ceramic matrix composite.

Description

Technical Field

[0001] The present invention relates to the field of materials science, and in particular to a hot wire chemical vapor deposition device for preparing high-quality SiC coatings or SiC nanowires and a preparation method thereof. The device achieves efficient and stable material synthesis by precisely controlling reaction conditions, and is suitable for fields such as ceramic-based composite material repair. Background Art

[0002] Since the 20th century, CVD technology has been one of the core technologies for synthesizing high-quality thin films, coatings and nanostructures in the field of materials science and engineering. With the rapid development of the semiconductor industry, optoelectronics, energy materials and nanotechnology, the application scope of CVD technology has been continuously expanded, and the requirements for material performance have become increasingly stringent. Especially in the preparation of SiC materials, due to its excellent physical and chemical properties, such as high hardness, high thermal conductivity, high temperature resistance and excellent electronic properties, SiC has a wide range of application potentials in power electronic devices, high temperature sensors, radiation detectors and optoelectronic devices. Therefore, it is particularly important to develop efficient and reliable SiC synthesis methods.

[0003] Although traditional CVD technology has made remarkable achievements in material preparation, it still faces a series of technical challenges in preparing high-quality SiC coatings or nanowires. These problems mainly include but are not limited to the following aspects:

[0004] 1. Reaction chamber design and vacuum control

[0005] The reaction chamber is the heart of the CVD process, and its design directly affects the efficiency of the reaction and the purity of the product. An ideal reaction chamber should be able to quickly and evenly reach the required vacuum level and remain stable during the reaction. However, traditional reaction chamber designs often have difficulty achieving low vacuum levels (such as less than 100 Pa) in a short period of time, and are prone to leakage during long-term operation, resulting in contamination of the reaction atmosphere and affecting the final performance of the material.

[0006] 2. Temperature uniformity and control

[0007] The synthesis of SiC needs to be carried out under high temperature conditions, and has extremely high requirements for temperature uniformity. Uneven temperature distribution will lead to non-uniform material growth, affecting the structural integrity and performance of SiC coatings or nanowires. Traditional heating methods, such as external heating or single heat source heating, often make it difficult to ensure uniform temperature across the reaction chamber or sample surface.

[0008] 3. Gas flow and reaction gas control

[0009] The selection and control of reaction gases are key factors in determining the morphology and properties of products during the CVD process. The precise ratio and flow rate of gases such as H2, Ar, and MTS have a direct impact on the growth rate, crystal phase, crystallinity, and defect density of SiC. Conventional CVD devices often fail to achieve ideal gas mixing and distribution, resulting in low reaction efficiency or unstable product quality.

[0010] 4. Sample processing and precise position control

[0011] The growth of SiC coatings or nanowires is very sensitive to the relative position between the sample and the heat source. Precisely controlling the distance between the sample and the hot wire not only helps to achieve a specific growth pattern, but also avoids thermal damage. However, many existing devices have limitations in sample loading, positioning, and the control of the relative position of the hot wire and the sample, making it difficult to meet the needs of refined growth.

[0012] 5. Operation process and degree of automation

[0013] An efficient and reliable CVD process often requires precise operating steps and a high degree of automated control. Manual operation is not only inefficient, but also prone to human errors, affecting batch-to-batch consistency. Therefore, developing an integrated and automated operating process is crucial to improving production efficiency and product quality.

[0014] In view of the above technical challenges, researchers are constantly exploring new design concepts and technical solutions to solve these problems and promote the advancement of CVD technology. For example, a multi-point heating system is used to improve temperature uniformity, a more advanced gas injection system is designed to optimize gas mixing and distribution, and an intelligent control system is developed to improve the level of automation of operations. However, these improvement solutions are often accompanied by problems such as increased costs and increased system complexity, which limits their widespread application in actual production.

[0015] Therefore, developing a hot wire CVD device and its preparation method that can not only ensure the synthesis efficiency and quality of SiC materials, but also have a simple structure, convenient operation, and high cost-effectiveness has become an urgent problem to be solved in the current field of materials science and engineering technology.

[0016] The present invention comes into being in such a background, and aims to overcome the deficiencies of the prior art through innovative design concepts and optimized preparation processes, and to provide a new solution for the efficient preparation of SiC materials. Summary of the invention

[0017] The present invention proposes a novel hot wire CVD device and its preparation method, aiming to solve the challenges of temperature uniformity, gas control, vacuum maintenance, sample positioning and preparation automation encountered by traditional CVD technology in the process of preparing high-quality SiC coatings or nanowires. The invention achieves high efficiency and excellent quality of SiC material synthesis through a carefully designed device structure and optimized operation process, which is particularly suitable for scientific research experiments and industrial production scenarios.

[0018] The hot wire CVD device of the present invention is composed of a plurality of key components, including but not limited to: 10 quartz glass cover, 20 base,

[0019] 30 outlet vent pipe, 40 electrode, 50 notched sample, 60 hot wire, 70 inlet vent pipe, 80 upper and lower actuator shafts, 90 vacuum gauge, 100 infrared thermometer, 110 high temperature observation window. Among them, the quartz glass cover is designed to seal the reaction chamber to ensure the purity and stability of the internal environment; the electrode serves as a supporting platform for the hot wire, which is convenient for the installation and adjustment of the hot wire; the outlet vent pipe is connected to the vacuum pump to quickly reach and maintain the required low vacuum degree; the upper and lower actuator shafts control the relative position of the sample and the hot wire to achieve precise growth control. It is characterized by comprising two major parts: a quartz glass cover and a base. The base is equipped with an inlet vent pipe, an outlet vent pipe, electrodes, upper and lower actuator shafts, a vacuum gauge, and an infrared thermometer. The quartz glass cover and the base constitute a vacuum chamber, and the chamber contains a hot wire and a substrate.

[0020] A material defect repair hot wire CVD device and an operating method thereof, characterized in that it comprises two major parts, namely a quartz glass cover and a base, on which an air inlet vent pipe, an air outlet vent pipe, electrodes, upper and lower actuating shafts, a vacuum gauge, an infrared thermometer, and a high-temperature observation window are installed, and the quartz glass cover and the base form a vacuum chamber, in which there are hot wires and substrate samples; the operating steps of the device are as follows:

[0021] (1) dropping an aqueous solution of nickel nitrate or the like into the notch of the substrate sample;

[0022] (2) Open the quartz glass cover;

[0023] (2) A hot wire is set up on the electrode. The hot wire can penetrate the substrate sample or pass through the gap.

[0024] (3) Clamping the substrate sample to be deposited at the top of the upper and lower actuating shafts;

[0025] (4) Fasten the quartz glass cover;

[0026] (5) Connect a vacuum pump through the air outlet vent pipe and turn on the vacuum pump to evacuate the vacuum chamber;

[0027] (6) Turn on the power and heat the hot wire;

[0028] (7) After the temperature of the hot wire reaches the required level, the air inlet vent pipe is opened to introduce the reactive mixed gas to start chemical vapor deposition of silicon carbide nanowires;

[0029] (8) Slowly raising and lowering the actuating shaft and adjusting the distance between the substrate and the hot wire to obtain the deposition quality and deposition direction of the deposit;

[0030] (9) Measure and record the thickness or length of sediment growth through the observation window;

[0031] (10) When the deposition requirements are met, the reaction gas is replaced and the pyrolytic carbon coating is deposited;

[0032] (11) When the deposition requirements are met, the reaction gas is replaced and the boron nitride coating is deposited;

[0033] (12) After the deposition is completed, the reactive gas is turned off and the inert gas is continued to be introduced;

[0034] (13) Close the air outlet vent pipe, wait for the quartz glass cover to loosen naturally, and then remove the quartz glass cover;

[0035] (14) Turn off the inert gas and remove the substrate sample from the hot wire.

[0036] Structural innovation: This device adopts a unique sample design (50 notched samples) and (60 hot wires) are inserted into the notches of the samples to achieve a very close but non-contact heating mode. This design not only ensures the effectiveness of heat transfer, but also avoids thermal stress damage that may be caused by direct contact, thereby promoting the uniform and directional growth of SiC materials.

[0037] Vacuum system optimization: Through optimized exhaust pipeline design (30 air outlet vent pipe) combined with an efficient vacuum pump, the present invention can evacuate the reaction chamber to a low vacuum degree below 10Pa in a short time, effectively eliminating impurity gases in the reaction process, ensuring the purity of the reaction environment, and is beneficial to improving the purity and crystallization quality of SiC materials.

[0038] Gas control strategy: The precise design of (70 air inlet vent pipe) enables the reaction gas (H2, Ar, MTS) to be accurately controlled in flow and proportion. Through the intelligent control system adjustment, the uniformity of gas mixing and the efficient reaction are ensured, providing a good chemical environment for the high-quality synthesis of SiC.

[0039] Automated operation process: The preparation method of the present invention is an orderly sequence of steps, from opening the quartz glass cover (10) to finally taking out the sample and checking the growth condition, each step is carefully designed. In particular, the slow movement of the upper and lower actuating shafts (80) allows the sample to gradually approach the hot wire under precise control. This automated process improves the repeatability of the reaction and the efficiency of sample processing, and reduces human errors.

[0040] Temperature and atmosphere control: After the hot wire (60) is heated, the stable electric heat source provided by the electrode (40) combined with the precise temperature sensing and control system ensures uniform and precise control of the temperature in the reaction chamber. After the reaction is completed, the sample is effectively protected and unnecessary oxidation or contamination is prevented by gradually shutting off the reaction gas (MTS and H2) and maintaining the Ar gas flow.

[0041] Advantages of the invention: The hot wire CVD device and the operation method thereof of the invention effectively solve many problems in the prior art through a series of innovative designs and optimization strategies, open up a new way for the growth of SiC nanowire materials at the gaps of ceramic-based composite materials, avoid the adverse effects of high temperature on the entire component for micro-area repair of silicon carbide ceramic-based composite materials, and improve the reliability of the material. It not only has important value in scientific research, but also provides a strong technical guarantee for the upgrading and transformation of related industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 Schematic diagram of the device of the present invention.

[0043] In the figure: 10 quartz glass cover, 20 base, 30 air outlet vent pipe, 40 electrode, 50 sample with notch, 60 hot wire, 70 air inlet vent pipe, 80 upper and lower actuating shafts and 90 vacuum gauge, 100 infrared thermometer, 110 high temperature observation window. DETAILED DESCRIPTION

[0044] The present invention will be further described with reference to the embodiments:

[0045] Example 1: Construction of U-shaped gap repair device and preparation of silicon carbide nanowires Operation steps:

[0046] 1. Device construction: Construct a hot-wire CVD device, including but not limited to a quartz glass cover, a base outlet vent pipe connected to a high vacuum pump, an electrode, a silicon carbide ceramic-based composite material sample with a U-shaped notch, a hot wire heated by a resistor and fixed on the electrode, a reaction gas inlet system, an upper and lower actuating shaft for adjusting the distance between the sample and the hot wire, and a vacuum gauge for monitoring the internal vacuum and an infrared thermometer for detecting the temperature of the hot wire.

[0047] 2. Operation process:

[0048] (1) Open the quartz glass cover to ensure operation in a dust-free environment;

[0049] (2) Fix the hot wire on the electrode and ensure that the hot wire is in the preset position;

[0050] (3) Place the ceramic matrix composite sample with a U-shaped notch on the top of the upper and lower actuating shafts below the hot wire and clamp it. Drop a dilute nickel nitrate solution into the U-shaped notch. Raise the sample so that the hot wire is inserted into the U-shaped notch but does not actually contact the sample. The distance between the two is controlled at the micrometer level.

[0051] (4) Fasten the quartz glass cover to seal the reaction chamber;

[0052] (5) Turn on the vacuum pump and extract air through the air outlet vent pipe until the vacuum degree drops below 100 Pa;

[0053] (6) Turn on the heating wire and set the temperature to 1100°C;

[0054] (7) Introducing reaction gases, the flow rates of H2 gas are set to 20 sccm, Ar gas to 50 sccm, and MTS gas to 5 sccm;

[0055] (8) Start the upper and lower actuators and slowly lower the sample at a speed of 0.1 mm / min, so that the sample is gradually heated under the hot wire to promote the chemical vapor deposition of SiC nanowires from the bottom to the top;

[0056] (9) After the predetermined reaction time, the MTS and H2 gas supplies are turned off in turn, and Ar gas is continued to be introduced for cooling protection, while the hot wire power supply is cut off;

[0057] (10) Close the gas outlet vent pipe, wait for the pressure in the reaction chamber to return to a certain level, close all gas supplies, and when the quartz glass cover can be easily opened, open the quartz glass cover;

[0058] (11) Take out the samples and examine the growth of SiC nanowires using scanning electron microscopy, transmission electron microscopy, etc., and evaluate their morphology, structure, and performance.

[0059] Example 2: Construction of O-shaped gap repair device and preparation of silicon carbide nanowires Operation steps:

[0060] 1. Device construction: Construct a hot-wire CVD device, including but not limited to a quartz glass cover, a base outlet vent pipe connected to a high vacuum pump, an electrode, a silicon carbide ceramic-based composite material sample with an O-notch, a hot wire heated by a resistor and fixed on the electrode, a reaction gas inlet system, an upper and lower actuating shaft for adjusting the distance between the sample and the hot wire, and a vacuum gauge for monitoring the internal vacuum and an infrared thermometer for detecting the temperature of the hot wire.

[0061] 2. Operation process:

[0062] (1) dripping a dilute aqueous nickel nitrate solution into the notch of a ceramic matrix composite material sample with an O-notch in advance, opening the quartz glass cover, and ensuring the operation in a dust-free environment;

[0063] (2) The hot wire passes through the O-shaped notch hole of the sample and the two ends of the hot wire are fixed on the electrode to ensure that the hot wire is in the preset position;

[0064] (3) The top of the upper and lower actuating shafts below the hot wire clamps the O-notch sample, and the actuating shafts are raised and lowered to push the sample so that the center axis of the O-notch circular hole of the sample is coaxial with the hot wire;

[0065] (4) Fasten the quartz glass cover to seal the reaction chamber;

[0066] (5) Turn on the vacuum pump and extract air through the air outlet vent pipe until the vacuum degree drops below 10Pa;

[0067] (6) Turn on the heating wire and set the temperature to 1300°C;

[0068] (7) Introducing reaction gases, the flow rates of H2 gas were set to 50 sccm, Ar gas to 100 sccm, and MTS gas to 5 sccm;

[0069] (8) After the predetermined reaction time, the MTS and H2 gas supplies are turned off in turn, and Ar gas is continued to be introduced for cooling protection, while the power supply of the hot wire is cut off;

[0070] (9) Close the gas outlet vent pipe, wait for the pressure in the reaction chamber to return to a certain level, close all gas supplies, and when the quartz glass cover can be easily opened, open the quartz glass cover;

[0071] (10) Take out the samples and examine the growth of SiC nanowires using scanning electron microscopy, transmission electron microscopy, etc., and evaluate their morphology, structure, and performance.

[0072] Example 3: Construction of V-notch and O-notch repairing device and preparation of silicon carbide nanowires and pyrolytic carbon coatings Operation steps:

[0073] 1. Device construction: Construct a hot-wire CVD device, including but not limited to a quartz glass cover, a base outlet vent pipe connected to a high vacuum pump, electrodes, silicon carbide ceramic-based composite samples with V-notch and O-notch, hot wires heated by resistors and fixed on electrodes, a reaction gas inlet system, upper and lower actuators for adjusting the distance between the sample and the hot wire, as well as a vacuum gauge for monitoring the internal vacuum, an infrared thermometer for detecting the hot wire temperature, and a high-temperature observation window for detecting the growth condition.

[0074] 2. Operation process:

[0075] (1) Preliminarily drip a dilute aqueous nickel nitrate solution into the notch of a ceramic matrix composite material sample with a V-notch or an O-notch, and open the quartz glass cover to ensure that the operation is carried out in a dust-free environment;

[0076] (2) The hot wire passes through the O-shaped notch hole of the sample and the two ends of the hot wire are fixed on the electrode to ensure that the hot wire is in the preset position;

[0077] (3) The top of the upper and lower actuating shafts below the hot wire clamps the V-notch sample and the O-notch sample, and the actuating shafts are raised and lowered to push the sample so that the center axis of the O-notch hole of the sample is coaxial with the hot wire, and the center line of the V-notch is coaxial with the hot wire, and the hot wire does not fall into the V-notch;

[0078] (4) Fasten the quartz glass cover to seal the reaction chamber;

[0079] (5) Turn on the vacuum pump and extract air through the air outlet vent pipe until the vacuum degree drops below 50Pa;

[0080] (6) Turn on the heating wire and set the temperature to 1200°C;

[0081] (7) Introducing reaction gases, the flow rates of H2 gas were set to 50 sccm, Ar gas to 100 sccm, and MTS gas to 5 sccm;

[0082] (8) After 5 hours of reaction time, turn off the MTS and H2 gas supplies in turn;

[0083] (9) Replace MTS with methane or propylene gas at a gas flow rate of 10 sccm and continue deposition;

[0084] (10) After 3 hours, close the reaction gas inlet pipe and only allow Ar to continue to flow in;

[0085] (11) Close the exhaust pipe, wait for the pressure in the reaction chamber to return to a certain level, close all gas supplies, and when the quartz glass cover can be easily opened, open the quartz glass cover;

[0086] (10) Take out the samples and examine the growth of SiC nanowires and pyrolytic carbon using scanning electron microscopy, transmission electron microscopy, etc., and evaluate their morphology, structure, and performance.

[0087] The hot wire CVD device and preparation method thereof of the present invention, through a series of innovative designs and optimization measures, not only simplifies the operation process and improves the synthesis efficiency, but also significantly improves the quality of SiC materials, providing a more reliable and efficient preparation technology for the application of SiC in high-tech fields.

Claims

1. A material defect repair hot wire CVD device and an operation method thereof, characterized in that It consists of two parts: a quartz glass cover and a base. The base is equipped with an air inlet vent pipe, an air outlet vent pipe, electrodes, upper and lower actuating shafts, a vacuum gauge, an infrared thermometer, and a high-temperature observation window. The quartz glass cover and the base form a vacuum chamber, and the chamber contains a hot wire and a substrate sample. The operating steps of the device are as follows: (1) dropping an aqueous solution of nickel nitrate or the like into the notch of the substrate sample; (2) Open the quartz glass cover; (2) A hot wire is set up on the electrode. The hot wire can penetrate the substrate sample or pass through the gap. (3) Clamping the substrate sample to be deposited at the top of the upper and lower actuating shafts; (4) Fasten the quartz glass cover; (5) Connect a vacuum pump through the air outlet vent pipe and turn on the vacuum pump to evacuate the vacuum chamber; (6) Turn on the power and heat the hot wire; (7) After the temperature of the hot wire reaches the required level, the air inlet vent pipe is opened to introduce the reactive mixed gas to start chemical vapor deposition of silicon carbide nanowires; (8) Slowly raising and lowering the actuating shaft and adjusting the distance between the substrate and the hot wire to obtain the deposition quality and deposition direction of the deposit; (9) Measure and record the thickness or length of sediment growth through the observation window; (10) When the deposition requirements are met, the reaction gas is replaced and the pyrolytic carbon coating is deposited; (11) When the deposition requirements are met, the reaction gas is replaced and the boron nitride coating is deposited; (12) After the deposition is completed, the reactive gas is turned off and the inert gas is continued to be introduced; (13) Close the air outlet vent pipe, wait for the quartz glass cover to loosen naturally, and then remove the quartz glass cover; (14) Turn off the inert gas and remove the substrate sample from the hot wire.

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