Device system for single crystal diamond synthesis

Abstract

The utility model relates to the technical field of preparation of monocrystal diamond by a microwave plasma chemical vapor deposition method, in particular to a device system for synthesizing monocrystal diamond. The single crystal diamond synthesis device system comprises a reaction cavity, a growth base table is arranged in the reaction cavity, and the reaction cavity is connected with an input pipeline, an exhaust pipeline and a two-way pipeline. A gas mixing valve is arranged on the input pipeline, the gas mixing valve is connected with a special gas pipeline for conveying process gas, and a mass flow meter and a pneumatic diaphragm valve are arranged on the special gas pipeline; the fine pumping valve and the vacuum pump are connected with the baffle valve in parallel, and the vacuum pump is connected to the downstream of the baffle valve and the fine pumping valve in series; and a vacuum gauge and a deflation valve are arranged on the two-way pipeline. According to the device system for synthesizing the single crystal diamond, influence factors such as process gas flow and cavity air pressure in the process of preparing the single crystal diamond by using the MPCVD method are accurately regulated and controlled, and the single crystal diamond can be conveniently prepared by using the MPCVD method.

Description

Technical Field

[0001] The utility model relates to the technical field of preparing single crystal diamond by microwave plasma chemical vapor deposition method, in particular to a device system for synthesizing single crystal diamond. Background Art

[0002] As a semiconductor material, single-crystal diamond possesses exceptional physical and chemical properties, including extremely high thermal conductivity, extremely low thermal expansion coefficient, high chemical inertness, extremely high acoustic propagation velocity at room temperature, and high transparency from the far infrared to the deep ultraviolet. These properties hold great promise for its broad application. However, the scarcity of naturally occurring single-crystal diamonds makes their large-scale application difficult.

[0003] The preparation methods of single-crystal diamond mainly include high-temperature and high-pressure method and chemical vapor deposition method. The high-temperature and high-pressure method simulates the formation environment of natural single-crystal diamond, crystallizing carbon elements under high temperature and high pressure conditions to form single-crystal diamond. However, the single-crystal diamond prepared by this method is limited in size and costly, so it is subject to certain restrictions in large-scale industrial applications. Chemical vapor deposition is currently the mainstream method for preparing single-crystal diamond, among which microwave plasma chemical vapor deposition (MPCVD) is particularly prominent. Microwave plasma chemical vapor deposition uses microwave electromagnetic fields to convert process gases such as methane into plasma in a reaction chamber, and then the plasma is deposited on the substrate surface to grow single-crystal diamond with excellent crystal quality and specific physical and chemical properties.

[0004] The process gas flow, chamber pressure, and ambient temperature during the growth of single-crystal diamond are important factors affecting its growth quality. Therefore, when using the MPCVD method to prepare single-crystal diamond, the process gas flow, chamber pressure, and ambient temperature must be precisely controlled. The ambient temperature can be adjusted by power and pressure. Therefore, it is necessary to design a gas control system for the MPCVD method to precisely control influencing factors such as process gas flow and chamber pressure. Utility Model Content

[0005] The purpose of the utility model is to provide a device system for single crystal diamond synthesis, so as to solve the problem of regulating process gas flow and cavity gas pressure in the process of preparing single crystal diamond using MPCVD method.

[0006] In order to solve the above problems, the present invention adopts the following technical solutions for a device system for single crystal diamond synthesis:

[0007] A device system for single-crystal diamond synthesis comprises a reaction chamber, wherein a growth base is provided in the reaction chamber, and the reaction chamber is connected to an input pipe, an exhaust pipe and a two-way pipe; the input pipe is provided with a gas mixing valve, the gas mixing valve is connected to a special gas pipe for conveying process gas, and the special gas pipe is provided with a mass flow meter and a pneumatic diaphragm valve; the exhaust pipe is provided with a baffle valve, a fine extraction valve connected in parallel with the baffle valve, and a vacuum pump, and the vacuum pump is connected in series downstream of the baffle valve and the fine extraction valve; a vacuum gauge and an air release valve are sequentially provided on the two-way pipe with the reaction chamber as the starting point.

[0008] Furthermore, the special gas pipeline includes a hydrogen pipeline, a methane pipeline, an oxygen pipeline, a nitrogen pipeline and an argon pipeline.

[0009] Furthermore, a one-way valve is provided on the special gas pipeline, and the one-way valve is connected in series upstream of the pneumatic diaphragm valve.

[0010] Furthermore, a special gas filter is provided on the special gas pipeline, and the special gas filter is connected in series upstream of the one-way valve.

[0011] Furthermore, a special gas filter is provided on the input pipeline, and the special gas filter is connected in series between the reaction chamber and the gas mixing valve.

[0012] Furthermore, an exhaust gas filter is provided on the exhaust pipe, and the exhaust gas filter is connected in series between the reaction chamber and the fine pumping valve.

[0013] Furthermore, a proportional valve is provided downstream of the fine pumping valve, and the proportional valve is connected in series downstream of the fine pumping valve.

[0014] Furthermore, an exhaust gas filter is provided on the exhaust pipe, and the exhaust gas filter is connected in series downstream of the vacuum pump.

[0015] Furthermore, an air filter is provided on the bidirectional pipeline, and the air filter is connected in series upstream of the air release valve.

[0016] Furthermore, there are two vacuum gauges, namely a high pressure range vacuum gauge and a low pressure range vacuum gauge.

[0017] Beneficial effects: The device system for single crystal diamond synthesis of the utility model is an improved invention. This solution provides a single-crystal diamond synthesis device system that precisely controls factors such as process gas flow and chamber pressure during the MPCVD process for single-crystal diamond production, thereby improving the quality of the produced single-crystal diamond. The valves and instruments in this device system can be controlled by an automated program, allowing for more precise control of the valves and instruments in the device system, thereby making process parameters in the single-crystal diamond production process more accurate and resulting in higher-quality single-crystal diamond produced using this device system. The mass flowmeter used in this device can precisely control the amount of process gas introduced, the pneumatic diaphragm valve controls the flow of gas in the pipeline, and the gas mixing valve controls the flow of mixed process gas. The reaction chamber provides a growth environment for plasma, the growth base provides for the deposition of carbon atoms, the vacuum pump maintains a vacuum environment to facilitate the formation of a stable plasma, and the flapper valve allows the vacuum pump to quickly reduce the pressure in the reaction chamber. Precise control of the valve core position accurately controls the vacuum level in the reaction chamber during plasma growth. The vacuum gauge records and displays the pressure in the reaction chamber in real time. When the vent valve is opened, atmospheric air enters the chamber, thereby achieving a vacuum-breaking operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a schematic flow chart of an embodiment of a device system for synthesizing single crystal diamond. DETAILED DESCRIPTION

[0019] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0020] The utility model discloses a device system for synthesizing single crystal diamonds, which uses a microwave plasma chemical vapor deposition method to simulate the natural environment in which single crystal diamonds are formed to prepare single crystal diamonds, thereby realizing artificial batch and automatic synthesis of single crystal diamonds.

[0021] As a basic solution, the present invention is a device for single crystal diamond synthesis comprising a reaction chamber, which provides a growth environment for plasma, a growth base is provided in the reaction chamber for depositing carbon atoms, and the reaction chamber is connected to an input pipe T1, an exhaust pipe T2 and a bidirectional pipe T3. Figure 1As shown, a mixing valve V6 is provided on the input pipeline T1, and the mixing valve V6 serves as a front-end control valve of the cavity. The mixing valve V6 is connected to the special gas pipeline T1-T5 for conveying process gas. The special gas pipeline T1-T5 is provided with a mass flow meter MFC1-MFC5 and a pneumatic diaphragm valve V1-V5. The special gas pipeline T1-T5 conveys the process gas into the mixing valve V6, and the process gas is mixed at the mixing valve V6 to form a mixed gas. The mixing valve V6 controls the on-off of the mixed gas entering the reaction chamber; the mass flow meter MFC1-MFC5 can accurately control the amount of process gas introduced under the control of the program, and the pneumatic diaphragm valve V1-V5 is automatically turned on and off according to the program instructions. The pneumatic diaphragm valve V1-V5 and the mass flow meter MFC1-MFC5 dually ensure the on-off of the process gas, avoiding the loss of the mass flow meter MFC1-MFC5 due to relying entirely on the on-off control of the mass flow meter MFC1-MFC5, and also avoiding abnormal fluctuations of the mass flow meter MFC1-MFC5. The process gas input into the chamber needs to diffuse and remix under a vacuum environment. Maintaining a vacuum environment helps to form a stable plasma. Therefore, a vacuum pump M1 is provided at the end of the exhaust pipe L3. A baffle valve V7 is provided on the exhaust pipe L3 to facilitate the vacuum pump M1 to quickly reduce the pressure in the reaction chamber. A fine pumping valve V8 is also provided on the exhaust pipe L3 in parallel with the baffle valve V7. The fine pumping valve V8 precisely controls the valve core position under the action of a set program, so as to further optimize the pressure in the reaction chamber under the action of the vacuum pump M1. A vacuum gauge and a bleed valve V10 are provided in sequence on the two-way pipe L3, starting from the reaction chamber. The vacuum gauge records, transmits and displays the pressure in the reaction chamber in real time through a program. The bleed valve is also called an inflation valve. When the bleed valve is opened, air in the atmosphere enters the chamber. The valves and instruments in this device system are all controlled by an automation device program to accurately control the opening and closing status of each valve in the system and the reading of the instrument.

[0022] As a preferred embodiment, the special gas pipeline includes a hydrogen pipeline T1, a methane pipeline T2, an oxygen pipeline T3, a nitrogen pipeline T4 and an argon pipeline T5, wherein hydrogen, methane and oxygen are used as raw process gases for preparing single crystal diamond, and nitrogen is introduced into the system as a catalyst. An appropriate concentration of nitrogen can increase the growth rate and synthesis quality of single crystal diamond; an appropriate amount of argon can improve the morphology and quality of single crystal diamond.

[0023] As a preferred embodiment, a one-way valve D1-D5 is provided upstream of the pneumatic diaphragm valve V-V5 on the special gas pipeline T1-T5. The one-way valve D1-D5 can effectively prevent the gas from other pipelines from flowing back into the abnormal pipeline when an abnormality occurs in a pipeline.

[0024] As a preferred embodiment, the special gas pipeline T1-T5 is provided with a special gas filter R1-R5, which filters the process gas transported from the special gas pipeline T1-T5 to the mixing valve V6 to remove impurities in the accompanying gas, thereby preventing impurity contamination from reducing the quality of the finished single crystal diamond and damaging other components in the gas system.

[0025] As a preferred embodiment, a higher-precision special gas filter R6 is added between the reaction chamber and the mixing valve V6. The special gas filter R6 further filters the process gas mixed by the mixing valve V6 to ensure that the gas entering the reaction chamber is absolutely pure and free of impurities.

[0026] As a preferred embodiment, an exhaust gas filter R7 is connected in series between the reaction chamber and the fine pumping valve V8. The exhaust gas filter R7 can effectively filter the impurities generated inside the reaction chamber to avoid contamination and clogging of subsequent valves in the system, thereby affecting the air pressure in the reaction chamber.

[0027] As a preferred embodiment, a proportional valve V9 is connected in series downstream of the fine pumping valve V8. The proportional valve V9 can accurately control the size of the cavity pressure to match the corresponding power and maintain the temperature of the single crystal diamond stable at the most suitable growth temperature.

[0028] As a preferred embodiment, an exhaust gas filter R9 is provided on the exhaust pipe L2, and the exhaust gas filter R9 is connected in series downstream of the vacuum pump M1. The exhaust gas filter R9 can effectively filter impurities such as oil mist generated by the vacuum pump M1 to avoid pollution of the workshop pipeline and the outdoor atmosphere.

[0029] As a preferred embodiment, an air filter R8 is provided on the bidirectional pipe L3. The air filter R8 is connected in series upstream of the air release valve V10, which can effectively filter impurities in the air. It can not only prevent impurities from clogging the air release valve V10 and the vacuum gauge, thereby affecting the accuracy of air pressure control, but also prevent impurities from entering the reaction chamber and affecting the quality of the next batch of single-crystal diamond products.

[0030] As a preferred embodiment, two vacuum gauges are provided, namely a high pressure range vacuum gauge Q1 and a low pressure range vacuum gauge Q2. The two vacuum gauges with different ranges can more accurately display the air pressure of the reaction chamber, which is convenient for program setting to adjust the switch of the baffle valve and the fine pumping valve.

[0031] The implementation process of this embodiment is as follows: first, close the vent valve V10, then open the vacuum pump M1 and the baffle valve V7 in sequence. The gas in the reaction chamber passes through the baffle valve V7 under the action of the vacuum pump M1 and is filtered by the exhaust filter R9 before being discharged from the system. The vacuum gauge Q1 and the vacuum gauge Q2 record and transmit the air pressure in the reaction chamber in real time through the program. After a certain vacuum degree is reached, open the fine adjustment valve V8 and the proportional valve V9; after the reaction chamber is evacuated to the ultimate vacuum, open the one-way valve D1-5, and the process gas passes through the special gas filters R1-R5, the pneumatic diaphragm valve V1-R5 and the mass flow meter MFC1- MFC15, mixes at the gas mixing valve V6, and the mixed gas is filtered by the special gas filter R6 before entering the reaction chamber. The mixed process gas entering the reaction chamber forms a plasma ball above the growth base under a specific gas pressure and microwave power. Then, under program control, the opening and closing degree of the proportional valve V9 is adjusted as the microwave power increases, so that the microwave power and the gas pressure in the reaction chamber match until the microwave power and gas pressure values ​​required by the process are reached, and the single crystal diamond begins to be synthesized stably; after the single crystal diamond growth is completed, the power and gas pressure are reduced by the proportional valve V9 and the microwave power, and then the process gas is stopped and the plasma ball is extinguished. Then the power and the fine pumping valve V8 are turned off, and the vent valve V10 is opened. The air is filtered by the air filter R8 and enters the reaction chamber to complete the vacuum breaking operation. The chamber cover can then be opened to take out the grown single crystal diamond wafer.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be based on the claims. Any equivalent structural changes made using the description and drawings of the present invention shall also be included in the scope of protection of the present invention.

Claims

1. A device system for single crystal diamond synthesis, comprising a reaction chamber, wherein a growth base is provided in the reaction chamber, characterized in that: The reaction chamber is connected to an input pipe, an exhaust pipe and a two-way pipe; a gas mixing valve is provided on the input pipe, and the gas mixing valve is connected to a special gas pipe for conveying process gas, and a mass flow meter and a pneumatic diaphragm valve are provided on the special gas pipe; the exhaust pipe is provided with a baffle valve, a fine pumping valve and a vacuum pump connected in parallel with the baffle valve, and the vacuum pump is connected in series downstream of the baffle valve and the fine pumping valve; a vacuum gauge and an air release valve are provided in sequence on the two-way pipe with the reaction chamber as the starting point.

2. The apparatus system for single crystal diamond synthesis according to claim 1, characterized in that: The special gas pipelines include hydrogen pipelines, methane pipelines, oxygen pipelines, nitrogen pipelines and argon pipelines.

3. The apparatus system for single crystal diamond synthesis according to claim 1, characterized in that: A one-way valve is provided on the special gas pipeline, and the one-way valve is connected in series upstream of the pneumatic diaphragm valve.

4. The apparatus system for single crystal diamond synthesis according to claim 3, characterized in that: A special gas filter is provided on the special gas pipeline, and the special gas filter is connected in series upstream of the one-way valve.

5. The device system for single crystal diamond synthesis according to claim 1, characterized in that: A special gas filter is provided on the input pipeline, and the special gas filter is connected in series between the reaction chamber and the gas mixing valve.

6. The device system for single crystal diamond synthesis according to claim 1, characterized in that: An exhaust gas filter is provided on the exhaust pipe, and the exhaust gas filter is connected in series between the reaction chamber and the fine pumping valve.

7. The device system for single crystal diamond synthesis according to claim 1, characterized in that: A proportional valve is provided downstream of the fine pumping valve, and the proportional valve is connected in series downstream of the fine pumping valve.

8. The apparatus system for single crystal diamond synthesis according to claim 1, characterized in that: An exhaust gas filter is provided on the exhaust pipe, and the exhaust gas filter is connected in series downstream of the vacuum pump.

9. The device system for single crystal diamond synthesis according to claim 1, characterized in that: An air filter is provided on the bidirectional pipeline, and the air filter is connected in series upstream of the air release valve.

10. The device system for single crystal diamond synthesis according to any one of claims 1 to 9, characterized in that: There are two vacuum gauges, a high pressure range vacuum gauge and a low pressure range vacuum gauge.

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