Annular waveguide electron cyclotron resonance plasma chemical vapor deposition device

Abstract

The invention discloses an annular waveguide electron cyclotron resonance plasma chemical vapor deposition device, and belongs to the field of microwave plasma method chemical vapor deposition. The device comprises a microwave power supply, a rectangular waveguide, a three-pin tuner, a short-circuit piston, an annular waveguide, an annular quartz window, a tungsten bias electrode, a cylindrical microwave resonant cavity, a temperature measurement observation window, an air inlet, an air outlet, a liftable substrate table tuning structure and a magnetic field system. The annular waveguide is combined with the cylindrical microwave resonant cavity, so that the axial symmetrical distribution of microwave energy can be realized, and the uniformity of the plasma is improved. The magnetic field system adopts double-layer magnetic field regulation and control, and the integral magnetic field and the plasma uniformity are optimized by independently adjusting the magnetic induction intensity. The pulsed bias power supply provides bias voltage for the substrate, and uniformity of the diamond in nucleation and growth on the heterogeneous substrate is promoted. The device is mainly used for preparing large-size heteroepitaxial single crystal diamond and polycrystalline diamond films, and high-quality uniform deposition of large-area diamond single crystal or polycrystalline films can be realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microwave plasma chemical vapor deposition, and particularly relates to a ring waveguide electron cyclotron resonance plasma chemical vapor deposition device. TECHNICAL BACKGROUND

[0002] Electron cyclotron resonance (ECR) plasma sources are used for a variety of material preparation and processing applications, such as thin film deposition, semiconductor etching. In ECR technology, the microwave frequency of the power source is the same as the frequency of the electron cyclotron motion, and the electrons produce resonant energy absorption, thereby obtaining an energy of up to 5 eV. High-energy electrons collide non-elastically with gas molecules to produce a large amount of high-activity plasma, and a high-density plasma can be generated even at very low pressure (0.05 Pa~1 Pa). 10 17 m -3 These advantages are suitable for plasma-assisted deposition of diamond, silicon, and in these deposition processes, high-quality thin films can be obtained while maintaining a low substrate temperature. At the same time, the electrodeless nature of microwave discharge, combined with the ability to produce high-density excited particles, makes microwave plasma chemical vapor deposition a promising technology for the preparation of diamond films. Since the emergence of MPCVD diamond film deposition technology, a series of MPCVD diamond film deposition devices have emerged, including quartz tube type, quartz bell type, cylindrical resonant cavity type, and ellipsoidal resonant cavity type. However, these devices generally have the disadvantages of plasma etching of the quartz dielectric window, large equipment footprint, high cost, and low utilization rate of the vacuum chamber. And for a 2.45 GHz microwave power source, the diameter of the diamond film that can be prepared by the device is usually 2 inch, which is difficult to meet the application requirements of diamond materials in large-size infrared windows, microwave windows, and heat sinks. At the same time, due to part assembly errors or machining errors, the traditional MPCVD device is prone to non-central symmetry of the plasma, causing non-uniform deposition of large-size diamond films. For this problem, the ring waveguide coupling method can achieve axial symmetric distribution of microwave energy, thereby improving the uniformity of the plasma.

[0003] On the other hand, in order to take advantage of the application of diamond in key fields such as ultraviolet detectors, radiation detectors, and field effect transistors, inch-level large-size single crystal diamond is needed. Heteroepitaxial growth is an effective technology for preparing high-quality large-size single crystal diamond. In the process of heteroepitaxial single crystal diamond growth, the bias voltage technology plays a key role. The bias voltage accelerates the bombardment of charged particles in the plasma on the non-diamond substrate, triggering high-density nucleation of diamond, and then preparing large-size heteroepitaxial single crystal diamond on the Ir(100) substrate. Therefore, when considering the research and design of a 2.45 GHz ECR MPCVD device, it is necessary to consider the bias voltage electrode components.

[0004] In summary, in order to realize the low equipment cost preparation and industrial application of large size polycrystalline diamond film and large size single crystal diamond, through equipment structure design and optimization, an annular waveguide electron cyclotron resonance plasma chemical vapor deposition device with a bias electrode structure is developed to improve the large area uniformity of the plasma and realize the preparation of inch level large size heteroepitaxial single crystal, and the size of the depositable diamond film is expanded from Φ2 inch to 3 inch (Φ76.2 mm), which is very meaningful to the development of MPCVD technology. SUMMARY

[0005] In order to solve the above problems, the purpose of the present application is to provide an annular waveguide electron cyclotron resonance plasma chemical vapor deposition device, The device can realize electron cyclotron resonance plasma discharge under high microwave input power condition and uniform preparation of large area polycrystalline diamond film or large size single crystal. The film deposition rate is high and the large area uniformity is good, the device structure is simple, the vacuum is good, the device can be stably operated and the parameters are easy to control. The annular waveguide of the device is combined with the cylindrical microwave resonant cavity, which can realize the axial symmetric distribution of microwave energy and improve the uniformity of the plasma. The magnetic field system adopts double-layer magnetic field regulation, which optimizes the whole magnetic field and the uniformity of the plasma by independently adjusting the magnetic induction intensity. The pulse bias power supply provides a bias voltage (100-300 V) for the substrate, which promotes the uniformity of diamond nucleation and growth on the hetero-substrate. Compared with the 2-inch effective deposition area of the typical TM01 or TM02 MPCVD device, the annular waveguide electron cyclotron resonance plasma chemical vapor deposition device can realize larger size electron cyclotron resonance plasma discharge, realize the preparation of inch level large size heteroepitaxial single crystal, and expand the effective deposition area to 3 inches or more, and greatly improve the uniformity of the plasma and the diamond film. 100~ 300 V), promote the uniformity of diamond nucleation and growth on the hetero-substrate. Compared with the 2-inch effective deposition area of the typical TM01 or TM02 MPCVD device, the annular waveguide electron cyclotron resonance plasma chemical vapor deposition device can realize larger size electron cyclotron resonance plasma discharge, realize the preparation of inch level large size heteroepitaxial single crystal, and expand the effective deposition area to 3 inches or more, and greatly improve the uniformity of the plasma and the diamond film.

[0006] In addition, the device for vacuum sealing quartz medium window is located on the side of the cylindrical resonator, away from the plasma, which solves the problem of impurity pollution caused by plasma etching of the quartz ring, so the device can be used for preparing large size electronic grade diamond film or heteroepitaxial single crystal. The prepared electronic grade diamond as a super wide band gap semiconductor material can be widely used in the field of semiconductors, such as high frequency electronic devices, millimeter wave devices, etc.

[0007] The technical scheme of the present application is: A ring waveguide electronic cyclotron resonance plasma chemical vapor deposition device includes a microwave power supply, a rectangular waveguide, a three-pin dispenser, a short-circuit piston, a ring waveguide, a ring quartz window, a tungsten bias electrode, a plasma, a cylindrical microwave resonant cavity, a temperature measurement observation window, an air inlet, an exhaust port, a liftable substrate stage tuning structure, and a magnetic field system. It is characterized in that the ring waveguide structure is connected to the microwave power supply through a WR430 rectangular waveguide, and the microwave energy is fed into the cylindrical microwave resonant cavity through the slit opening of the ring waveguide, forming an axially uniform microwave electric field distribution and improving the uniformity of the plasma. The height of the ring waveguide is the same as that of the WR430 rectangular waveguide, which is 54.61 mm. The outer diameter of the ring waveguide is 1.34mm. R Satisfies: 2λ< R <2.5λ, λ=122.4 mm is the wavelength of 2.45 GHz microwave. The outer diameter of the ring waveguide r Satisfies: 1.85λ< r <1.95λ. Ratio of outer diameter to inner diameter R / r =1.25 The slit opening length of the annular waveguide is 0.5λ=61.2 mm, corresponding to the nodes of the microwave standing wave in the waveguide. After the microwave energy passes through the slit opening, it passes through the annular quartz window and is finally fed into the cylindrical microwave resonant cavity.

[0008] Furthermore, the circular waveguide electron cyclotron resonance plasma chemical vapor deposition device described in the present invention has a magnetic field system including a circular magnetic field resonance coil and a magnetic field shaping coil. The circular magnetic field resonance coil and the magnetic field shaping coil are arranged around a cylindrical resonant cavity. By adjusting the DC power supply parameters, the electron cyclotron resonance frequency is matched with the microwave frequency, generating an electron cyclotron resonance surface with a magnetic induction intensity of 875 Gs.

[0009] Furthermore, the ring wave electron cyclotron resonance plasma chemical vapor deposition device described in the present invention has a liftable substrate stage tuning structure located at the center of the resonant cavity, and is provided by a pulse bias power supply. 100~ A 300 V potential promotes uniform diamond nucleation and growth on heterogeneous substrates. The elevating substrate stage is insulated from the cylindrical microwave resonant cavity by highly thermally conductive silicon carbide ceramic. The elevating substrate stage's tuning structure allows for up and down movement, enabling real-time tuning of the microwave electric field and plasma.

[0010] Further, the gas inlet of the ring waveguide electron cyclotron resonance plasma chemical vapor deposition device is located above the cylindrical resonant cavity, and every 90 degrees along the axial direction, one gas inlet is arranged, and there are four gas inlets in total; the gas outlet is located at the radial center position below the cylindrical resonant cavity structure, and every 60 degrees along the axial direction, one gas outlet is arranged, and there are six gas outlets in total, so that the uniformity of the gas flow field in the cylindrical resonant cavity is ensured.

[0011] Further, the ring waveguide electron cyclotron resonance plasma chemical vapor deposition device has one tungsten bias electrode arranged at the middle of the top of the cylindrical microwave resonant cavity, which is used to provide a bias electric field in the process of heteroepitaxial single crystal diamond growth, and enhance diamond nucleation.

[0012] Further, the ring waveguide electron cyclotron resonance plasma chemical vapor deposition device has a ring-shaped quartz window with a relative dielectric constant of 4.2, and a sealing groove is formed at the connection position between the ring-shaped quartz window and the stainless steel cylindrical resonant cavity, the ring-shaped quartz window is placed in the sealing groove, and an O-shaped rubber ring is arranged between the ring-shaped quartz window and the stainless steel inner wall.

[0013] Further, the ring waveguide electron cyclotron resonance plasma chemical vapor deposition device has a temperature measuring observation window arranged on the side of the cylindrical microwave resonant cavity, which is used for real-time observation of the plasma state and measurement of the substrate temperature.

[0014] Further, the ring waveguide electron cyclotron resonance plasma chemical vapor deposition device has a cylindrical microwave resonant cavity which is cooled by circulating water to avoid local overheating and ensure long-time operation of the equipment.

[0015] The working principle of the present application is as follows: the microwave power source generates microwaves with a frequency of 2.45 GHz, the microwaves are converted from TE mode to TM mode by WR430 rectangular waveguide through ring waveguide, and then enter the cylindrical microwave resonant cavity through the ring-shaped quartz window. A stable standing wave is formed in the cylindrical resonant cavity, and a strong electric field region is formed above the liftable substrate table tuning structure. The double-layer magnetic field system generates a convergent magnetic field, and the microwave power propagates along the convergent magnetic field and reaches the resonant surface. The electron cyclotron resonance frequency in the magnetic field at this position is equal to the frequency of the input microwaves. The reaction gas entering the resonant cavity from the inlet is broken down, and the plasma generated by strong absorption at the resonant surface moves along the magnetic field lines and interacts with the target substrate at the downstream, so as to realize the deposition of thin film. The bias electrode provides a bias electric field for the substrate, enhances the diamond nucleation on the substrate, and realizes the growth of heteroepitaxial single crystal diamond.

[0016] The key of the implementation process of the present application is: The application provides an electron cyclotron resonance plasma chemical vapor deposition device with a ring waveguide. The device mainly comprises a microwave power source, a rectangular waveguide, a three-pin tuner, a short-circuit piston, a ring waveguide, a ring quartz window, a tungsten bias electrode, a cylindrical microwave resonant cavity, a temperature measurement observation window, a gas inlet, an exhaust outlet, a liftable substrate table tuning structure, and a magnetic field system.

[0017] The ring waveguide structure is connected with the microwave power source through a WR430 rectangular waveguide. Microwave energy is fed into the cylindrical microwave resonant cavity through the slit opening of the ring waveguide, forming an axial uniform microwave electric field distribution and improving plasma uniformity. The height of the ring waveguide is the same as that of the WR430 rectangular waveguide, i.e. 54.61 mm. The outer diameter of the ring waveguide is 2.5λ, and the inner diameter is 1.95λ, where λ=122.4 mm is the wavelength of 2.45 GHz microwave. R R <2.5λ, λ=122.4 mm is the wavelength of 2.45 GHz microwave. The outer diameter of the ring waveguide is 2.5λ, and the inner diameter is 1.95λ. r r <1.95λ. The ratio of the outer diameter to the inner diameter is R r =1.25 0.05. The slit opening length of the ring waveguide is 0.5λ=61.2 mm, which corresponds to the nodes of the microwave standing wave in the waveguide. After the microwave energy passes through the slit opening, it passes through the ring quartz window and is finally fed into the cylindrical microwave resonant cavity. The combination of the ring waveguide and the cylindrical microwave resonant cavity can realize the axial symmetric distribution of microwave energy and improve plasma uniformity. The bias electrode provides a bias electric field during the heteroepitaxial growth of single crystal diamond, thereby enhancing diamond nucleation. The magnetic field system adopts a double-layer magnetic field regulation, and the magnetic induction intensity is independently adjusted to optimize the uniformity of the magnetic field and plasma. Compared with the 2-inch effective deposition area of a typical TM01 or TM02 MPCVD device, the present electron cyclotron resonance plasma chemical vapor deposition device can realize larger size plasma discharge and achieve inch-level large-size heteroepitaxial single crystal preparation, and the effective deposition area can be expanded to 3 inches.

[0018] The ring quartz window is located on the side of the cylindrical resonator and is far away from the plasma, thereby avoiding the etching of the quartz dielectric window by the plasma. The liftable substrate table tuning structure can move up and down for real-time tuning of the microwave electric field and plasma, and is insulated from the cylindrical microwave resonant cavity through high-thermal-conductivity silicon carbide ceramics. The device is mainly used for preparing heteroepitaxial single crystal diamond and polycrystalline diamond film, and can realize high-quality and uniform deposition of diamond single crystal or large-area thin film under high power and high cavity pressure.

[0019] The key to generating electron cyclotron resonance plasma and depositing heteroepitaxial single crystal diamond is to fix the substrate on the liftable substrate table tuning structure, vacuumize the chamber to 1.0 10​​​-4 Pa, after pumping to a predetermined vacuum, hydrogen and methane are introduced into the chamber, and the chamber pressure is maintained at 10 -2 Pa. The 2.45 GHz microwave power source is turned on, and the output power is adjusted to 0.6-2 kW. The three-pin tuner and the shorting piston are adjusted to minimize the microwave reflection coefficient. The direct current power source is turned on to ensure that the electron cyclotron resonance surface of the annular magnetic field resonant coil generates a magnetic induction intensity of 875 Gs, and the annular magnetic field shaping coil generates a convergent shaping magnetic field with a magnetic induction intensity of 875 Gs. The pulsed bias power source is turned on, and the pulsed bias power source is adjusted to make the substrate bias potential 100- 300 V. The ideal electron cyclotron resonance plasma discharge state of the diamond thin film deposition process is reached. After the thin film deposition is completed, the power is turned off, the gas is turned off, and the machine is turned off after being pumped to the limit vacuum.

[0020] The present application has the following beneficial effects compared with the prior art: The present application proposes a kind of annular waveguide electron cyclotron resonance plasma chemical vapor deposition device, relative to traditional microwave plasma chemical deposition device, in the present application, Annular waveguide structure is connected with microwave power source through WR430 rectangular waveguide, microwave energy is fed into cylindrical microwave resonant cavity through the slit opening of annular waveguide, forms axial uniform microwave electric field distribution, improves plasma uniformity. The height of annular waveguide is same with the height of WR430 rectangular waveguide, is 54.61 mm, the outer diameter of annular waveguide R Satisfies: 2λ< R <2.5λ, λ=122.4 mm is 2.45 GHz microwave wavelength. The outer diameter of annular waveguide r Satisfies: 1.85λ< r <1.95λ. The ratio of outer diameter and inner diameter R / r =1.25 0.05. The slit opening length of the annular waveguide is 0.5λ=61.2 mm, which corresponds to the wave node of the microwave standing wave in the waveguide. After the microwave energy passes through the slit opening, it passes through the annular quartz window and is finally fed into the cylindrical microwave resonant cavity. The combination of the annular waveguide and the cylindrical microwave resonant cavity can realize the axial symmetric distribution of the microwave energy and improve the plasma uniformity. The bias electrode provides a bias electric field during the heteroepitaxial growth of single crystal diamond and enhances the diamond nucleation. The magnetic field system adopts double-layer magnetic field regulation. By independently adjusting the magnetic induction intensity, the uniformity of the plasma and the shaped magnetic field are optimized. Compared with the 2-inch effective deposition area of the typical TM01 or TM02 MPCVD device, the annular waveguide electron cyclotron resonance plasma chemical vapor deposition device can realize larger size plasma discharge and realize the preparation of inch-level large-size heteroepitaxial single crystal, and can expand the effective deposition area to 3 inches.

[0021] The annular quartz window is located on the side of the cylindrical resonator and is far away from the plasma, which avoids the etching of the quartz dielectric window by the plasma. The thin film deposition rate is high, the large-area uniformity is good, the device structure is simple, the vacuum is good, the device can be stably operated, and the parameters are easy to control. The liftable substrate table tuning structure can move up and down, which is used for real-time tuning of the microwave electric field and the plasma, and is insulated from the cylindrical microwave resonant cavity through high-thermal-conductivity silicon carbide ceramics. At the same time, since the device introduces a bias electrode, the bias electrode provides a bias electric field during the heteroepitaxial growth of single crystal diamond and enhances the diamond nucleation at the substrate, so the device can be used for the preparation of large-size heteroepitaxial single crystal diamond. The prepared heteroepitaxial single crystal diamond can be widely used in the field of semiconductor materials, such as ultraviolet detectors, radiation detectors, field effect transistors, etc. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The device is an annular waveguide electron cyclotron resonance plasma chemical vapor deposition device. 1, a 2.45 GHz microwave power supply; 2, a rectangular waveguide; 3, a short-circuit piston; 4, a three-pin tuner; 5, an annular waveguide; 6, a slit; 7, an annular quartz window; 8, a cylindrical microwave resonant cavity; 9, a tungsten bias electrode; 10, a plasma; 11, a liftable substrate table tuning structure; 12, an annular magnetic field resonant coil; 13, an annular magnetic field shaping coil; 14, a gas inlet; 15, an exhaust port; 16, a temperature measurement observation window.

[0023] Figure 2 The device is an annular waveguide electron cyclotron resonance plasma chemical vapor deposition device.

[0024] Figure 3is a numerical simulation magnetic induction intensity distribution result of an annular waveguide electron cyclotron resonance plasma chemical vapor deposition device based on the present application, the substrate diameter is 3 inch, and the magnetic induction intensity isosurface lines of 865, 870, 875, 880 and 885 Gs are marked on the figure. DETAILED DESCRIPTION

[0025] The technical solutions of the present application are further described below in combination with the drawings and specific embodiments: As shown in the figure, the present application proposes an annular waveguide electron cyclotron resonance plasma chemical vapor deposition device, the microwave resonant cavity and the vacuum chamber geometry are distributed in axial symmetry. The microwave energy generated by the 2.45 GHz microwave power supply (1) propagates along the rectangular waveguide (2), is coupled into the cylindrical microwave resonant cavity (8) through the slit (6) of the annular waveguide (5) and the annular quartz window (7), and the three-pin adjuster (4) and the short-circuit piston (3) are adjusted to minimize the microwave reflection coefficient. The gas inlet (14) is arranged at the center of the upper part of the cylindrical microwave resonant cavity (8), and the six exhaust outlets (15) are arranged at the radial center position of the lower part of the cylindrical microwave resonant cavity (8) along the axial direction. The annular magnetic field resonant coil (12) and the annular magnetic field shaping coil (13) are used to generate an electron cyclotron resonance plane with a magnetic induction intensity of 875 Gs. The tungsten bias electrode (9) and the liftable substrate table tuning structure (11) are connected by a direct current power supply to form a current loop. The substrate is placed on the liftable substrate table tuning structure (11), and the temperature observation window (16) is used for real-time temperature measurement during diamond growth.

[0026] Embodiment 1

[0027] A Φ60 mm single crystal silicon substrate is placed on the liftable substrate table tuning structure (11), the chamber is vacuumed to 1.0 10 -4 Pa, after being pumped to the predetermined vacuum, H2 is introduced into the resonant cavity as the working gas, after being pumped to the predetermined vacuum, H2 and CH4 are introduced into the cylindrical microwave resonant cavity (8) as the working gas, and the gas pressure is 0.1 Pa. Turn on the 2.45 GHz microwave power supply (1), adjust the output power to 1000 W, adjust the three-pin adjuster (4) and the short-circuit piston (3) to minimize the microwave reflection coefficient. Turn on the direct current power supply to ensure that the annular magnetic field resonant coil (12) generates an electron cyclotron resonance plane with a magnetic induction intensity of 875 Gs, and the annular magnetic field shaping coil (13) generates a convergent magnetic field with a magnetic induction intensity of 875 Gs. Turn on the pulsed bias power supply and adjust the pulsed bias power supply to make the substrate bias potential 200 V, to achieve the ideal electron cyclotron resonance plasma discharge state of the thin film deposition process. The plasma (10) in the cylindrical microwave resonant cavity (8) flows to the substrate surface to realize the deposition of the diamond thin film. After the diamond thin film deposition is completed, the power is turned off, the gas is turned off, and the machine is turned off after being pumped to the limit vacuum.

[0028] Example 2

[0029] A 3 inch single crystal silicon substrate is placed on the liftable substrate table tuning structure (11), and the chamber is pumped to 1.0 10 -4 Pa, H2 is introduced into the resonant cavity as the working gas after being pumped to the predetermined vacuum, and H2 and CH4 are introduced into the cylindrical microwave resonant cavity (8) as the working gas after being pumped to the predetermined vacuum, and the gas pressure is 0.1 Pa. Turn on the 2.45 GHz microwave power supply (1), adjust the output power to 1500 W, adjust the three-pin tuner (4) and the short-circuit piston (3) to minimize the microwave reflection coefficient. Turn on the direct current power supply to ensure that the annular magnetic field resonant coil (12) generates an electron cyclotron resonance surface with a magnetic induction intensity of 875 Gs, and the annular magnetic field shaping coil (13) generates a convergent magnetic field with a magnetic induction intensity of 875 Gs. Turn on the pulsed bias power supply and adjust the pulsed bias power supply to make the substrate bias potential 250 V, to achieve the ideal electron cyclotron resonance plasma discharge state of the thin film deposition process. The plasma (10) in the cylindrical microwave resonant cavity (8) flows to the substrate surface to realize the deposition of the diamond thin film. After the diamond thin film deposition is completed, the power is turned off, the gas is turned off, and the machine is turned off after being pumped to the limit vacuum.

[0030] Example 3

[0031] A 3 inch Ir thin film coated MgO substrate is placed on the liftable substrate table tuning structure (11), and the chamber is pumped to 1.0 10 -4 Pa, H2 is introduced into the resonant cavity as the working gas after being pumped to the predetermined vacuum, and H2 and CH4 are introduced into the cylindrical microwave resonant cavity (8) as the working gas after being pumped to the predetermined vacuum, and the gas pressure is 0.1 Pa. Turn on the 2.45 GHz microwave power supply (1), adjust the output power to 1500 W, adjust the three-pin tuner (4) and the short-circuit piston (3) to minimize the microwave reflection coefficient. Turn on the direct current power supply to ensure that the annular magnetic field resonant coil (12) generates an electron cyclotron resonance surface with a magnetic induction intensity of 875 Gs, and the annular magnetic field shaping coil (13) generates a convergent magnetic field with a magnetic induction intensity of 875 Gs. Turn on the pulsed bias power supply and adjust the pulsed bias power supply to make the substrate bias potential 300 V, to achieve the ideal electron cyclotron resonance plasma discharge state of the thin film deposition process. The plasma (10) in the cylindrical microwave resonant cavity (8) flows to the substrate surface to achieve deposition of the diamond thin film. After the diamond thin film deposition is completed, the power is turned off, the gas is turned off, and the machine is turned off after being pumped to the limit vacuum.

[0032] Example 4

[0033] Thirty-six 10 mm x 10 mm HTHP diamond seed substrates were placed in a 6 x 6 array on the liftable substrate table tuning structure (11), and the chamber was pumped to 1.0 10 -4 Pa, H2 was introduced into the resonant cavity as the working gas after being pumped to the predetermined vacuum, H2 and CH4 were introduced into the cylindrical microwave resonant cavity (8) as the working gas after being pumped to the predetermined vacuum, and the gas pressure was 0.1 Pa. The 2.45 GHz microwave power source (1) was turned on, the output power was adjusted to 2000 W, the three-pin tuner (4) and the short-circuit piston (3) were adjusted to minimize the microwave reflection coefficient. The direct current power source was turned on to ensure that the annular magnetic field resonant coil (12) generated an electron cyclotron resonance surface of a magnetic induction intensity of 875 Gs, and the annular magnetic field shaping coil (13) generated a convergent magnetic field of a magnetic induction intensity of 875 Gs. The pulsed bias power source was turned on, and the pulsed bias power source was adjusted so that the substrate bias potential was 250 V, to achieve the ideal electron cyclotron resonance plasma discharge state of the thin film deposition process. The plasma (10) in the cylindrical microwave resonant cavity (8) flows to the substrate surface to achieve deposition of the diamond thin film. After the diamond thin film deposition is completed, the power is turned off, the gas is turned off, and the machine is turned off after being pumped to the limit vacuum.

Claims

1. A ring waveguide electron cyclotron resonance plasma chemical vapor deposition apparatus, comprising a microwave power supply, a rectangular waveguide, a three-pin dispenser, a short-circuit piston, a ring waveguide, a ring quartz window, a tungsten bias electrode, a plasma, a cylindrical microwave resonant cavity, a temperature measurement observation window, an air inlet, an exhaust port, a liftable substrate stage tuning structure, and a magnetic field system, characterized in that: The annular waveguide structure is connected to the microwave power supply through the WR430 rectangular waveguide. The microwave energy is fed into the cylindrical microwave resonant cavity through the slit opening of the annular waveguide to form an axially uniform microwave electric field distribution, thereby improving the plasma uniformity. The height of the annular waveguide is the same as that of the WR430 rectangular waveguide. The outer diameter of the annular waveguide is R Satisfies: 2λ< R <2.5λ, where λ is the wavelength of a 2.45 GHz microwave; the outer diameter of the ring waveguide r Satisfies: 1.85λ< r <1.95λ; ratio of outer diameter to inner diameter R / r =1.25 0.05; the slit opening length of the annular waveguide is 0.5λ, which corresponds to the node of the microwave standing wave in the waveguide. After the microwave energy passes through the slit opening, it passes through the annular quartz window and is finally fed into the cylindrical microwave resonant cavity.

2. The ring wave electron cyclotron resonance plasma chemical vapor deposition device according to claim 1, characterized in that: The magnetic field system includes a toroidal magnetic field resonant coil and a toroidal magnetic field shaping coil, which are arranged around a cylindrical resonant cavity. By adjusting the DC power supply parameters, the electron cyclotron resonance frequency is matched with the microwave frequency, generating an electron cyclotron resonance surface with a magnetic induction intensity of 875 Gs.

3. The ring wave electron cyclotron resonance plasma chemical vapor deposition device according to claim 1, characterized in that: The liftable substrate stage tuning structure is located at the center of the resonant cavity and is provided with a pulse bias power supply. 100~ A potential of 300 V promotes uniformity in diamond nucleation and growth on heterogeneous substrates; the liftable substrate stage is insulated from the cylindrical microwave resonant cavity by high thermal conductivity silicon carbide ceramics; the liftable substrate stage tuning structure can move up and down for real-time tuning of the microwave electric field and plasma.

4. The ring wave electron cyclotron resonance plasma chemical vapor deposition device according to claim 1, characterized in that: The air inlet is located above the cylindrical resonant cavity, and an air inlet is set every 90° along the axial direction, with a total of 4 air inlets; the exhaust port is located at the radial center of the structure below the cylindrical resonant cavity, and an exhaust port is set every 60° along the axial direction, with a total of 6 exhaust ports, to ensure the uniformity of the gas flow field in the cylindrical resonant cavity.

5. The ring wave electron cyclotron resonance plasma chemical vapor deposition device according to claim 1, characterized in that: A tungsten bias electrode is provided in the middle of the upper part of the cylindrical microwave resonant cavity, which is used to provide a bias electric field during the heteroepitaxial single crystal diamond growth process to enhance diamond nucleation; a water cooling circuit is provided inside the bias electrode, and it is insulated from the cylindrical microwave resonant cavity by high thermal conductivity silicon carbide ceramic.

6. The ring wave electron cyclotron resonance plasma chemical vapor deposition device according to claim 1, characterized in that: The relative dielectric constant of the annular quartz window is 4.

2. A sealing groove is provided at the connection between the annular quartz window and the stainless steel cylindrical resonant cavity structure. The annular quartz window is placed in the sealing groove. A fixed O-type rubber ring is provided between the annular quartz window and the stainless steel inner wall.

7. The ring wave electron cyclotron resonance plasma chemical vapor deposition device according to claim 1, characterized in that: The temperature measurement observation window is located on the side of the cylindrical microwave resonant cavity and is used to observe the plasma state in real time and measure the substrate temperature.

8. The ring wave electron cyclotron resonance plasma chemical vapor deposition device according to claim 1, characterized in that: The cylindrical microwave resonant cavity is cooled by circulating water to avoid local overheating and ensure long-term operation of the equipment.

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