Large-size diamond microwave plasma growth equipment

Abstract

The invention relates to the technical field of diamond preparation, in particular to large-size diamond microwave plasma growth equipment which comprises a base and a console fixedly mounted on one side of the top end of the base, gas transmission ports communicated with the interior of the base are formed in the left side and the right side of the base, and a resonant cavity is fixedly mounted on the other side of the top end of the base. The top end of the resonant cavity is fixedly provided with a vacuum window communicated with the interior of the resonant cavity, the top end of the vacuum window is fixedly communicated with a waveguide tube, one side of the waveguide tube is connected with a plasma generation mechanism, and the other side of the waveguide tube is connected with a microwave generation mechanism. Uniform high-density plasma distribution is achieved through the cylindrical-conical resonant cavity and the adjustable magnetic field, multi-mode gas injection and substrate rotation cooperate to compensate edge active species attenuation and remove by-products, and multi-layer thermal management and material cooperation ensure stable substrate positioning and equipment durability. The growth quality and efficiency of the diamond film are integrally and remarkably improved, and meanwhile the growth rate and the film layer compactness are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of diamond preparation, and in particular to a large-size diamond microwave plasma growth device. Background Art

[0002] Diamond, with its unparalleled physical and chemical properties, holds a pivotal position in strategic fields such as mechanical manufacturing, electronic information, and thermal management. Its exceptional hardness, thermal conductivity, and electrical properties make it an ideal material for numerous high-end applications. With the rapid development of high-tech industries, market demand for diamond has seen explosive growth. However, due to complex preparation processes and high production costs, the large-scale application of this "king of materials" still faces severe challenges, and a critical need exists to overcome technical bottlenecks to unlock its enormous market potential.

[0003] In the field of diamond preparation technology, microwave plasma chemical vapor deposition (MPCVD) has emerged as a core process for high-quality diamond production due to its unique technical advantages. This method, with its high-power density plasma, zero electrode discharge pollution, and stable and reliable operation, has overcome the limitations of traditional preparation techniques and opened up a new path for the industrial production of diamond materials.

[0004] Currently, mainstream MPCVD diamond film deposition equipment, both domestically and internationally, generally employs the principle of resonant absorption, introducing carbon-containing process gases such as methane into the reaction chamber and exciting them with microwave energy to form a high-temperature plasma sphere. Beneath the plasma sphere, a precisely designed substrate stage serves as the growth base. In the high-temperature, highly active plasma environment, carbon atoms continuously deposit and crystallize, ultimately forming a high-quality diamond film, providing a key foundational material for fields such as electronics and optics. However, existing diamond films are prone to center-edge density differences and poor uniformity during production, as well as slow growth rates and insufficient surface finish. Summary of the Invention

[0005] The purpose of the present invention is to solve the above-mentioned shortcomings in the prior art and to propose a large-size diamond microwave plasma growth device.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A large-scale diamond microwave plasma growth device comprises a base and a control console fixedly mounted on one side of the top of the base. The base defines a cavity within the base, a sealed door is rotatably mounted on the front end of the base, and gas ports are provided on both left and right sides of the base, communicating with the interior of the base. A resonant cavity is fixedly mounted on the other side of the top of the base, a vacuum window is fixedly mounted on the top of the resonant cavity, communicating with the interior of the base, and a waveguide is fixedly connected to the top of the vacuum window. A plasma generating mechanism is connected to one side of the waveguide, and a microwave generating mechanism is connected to the other side.

[0008] A fixing frame is fixedly installed in the cavity of the base, a coating frame is provided inside the fixing frame, a driving mechanism is connected to the lower end of the coating frame, a molybdenum plate and a copper plate are placed in sequence from top to bottom inside the coating frame, and the substrate is placed in the middle of the molybdenum plate;

[0009] A working frame is detachably mounted on the top of the fixed frame. A first injection mechanism for outputting acetylene is provided on one side of the working frame, a second injection mechanism for outputting a mixed gas of oxygen and hydrogen is provided on the other side of the working frame, and a third injection mechanism for outputting a mixed gas of methane and hydrogen is provided above the working frame.

[0010] Preferably, the resonant cavity adopts a structural design in which the upper end is cylindrical and the lower end gradually transitions to a cone shape, and an observation window communicating with the interior of the resonant cavity is fixedly mounted on the side of the resonant cavity.

[0011] Preferably, the plasma generating mechanism includes a transmission tube fixedly connected to the waveguide tube, one end of the transmission tube away from the waveguide tube is connected to a plasma generator, and the plasma generator is fixedly installed at the rear end of the base.

[0012] Preferably, the microwave generating mechanism comprises a microwave tube fixedly connected to the waveguide tube, and one end of the microwave tube away from the waveguide tube is connected to the microwave generator.

[0013] Preferably, a protective frame is movably provided below the resonant cavity, a cavity is formed between the protective frame and the outer wall of the resonant cavity, and a magnetic field coil is provided inside the cavity and is sleeved on the outside of the resonant cavity.

[0014] Preferably, the driving mechanism includes a driving motor fixedly mounted on the inner bottom wall of the fixing frame, the output end of the driving motor faces upward and is keyed to a connecting rod, and the top end of the connecting rod is fixedly connected to the coating frame.

[0015] Preferably, the surface of the coating frame is plated with a nanocrystalline diamond coating, and the upper surface of the molybdenum plate is provided with staggered microchannels.

[0016] Preferably, the first injection mechanism includes an arc-shaped groove arranged on the inner side of the working frame, a sealing cover is provided at the upper end of the arc-shaped groove, a plurality of escape holes are provided at equal intervals on one side of the arc-shaped groove, and the plurality of escape holes are all facing the substrate side, an air inlet is provided on one side of the fixed frame, and a pipeline for supplying acetylene is connected to the arc-shaped groove through the air delivery port and the air inlet.

[0017] Preferably, the second injection mechanism includes an auxiliary nozzle provided on the inner side of the working frame, the auxiliary nozzle and the arc-shaped groove are symmetrically distributed, and a pipeline for supplying a mixed gas of oxygen and hydrogen is connected to the auxiliary nozzle through a gas delivery port.

[0018] Preferably, the third injection mechanism includes an annular tube, which is fixedly connected to the inner top wall of the base by a fixing rod. A plurality of nozzles are provided at equal intervals at the lower end of the annular tube. The nozzles are arranged at an angle and the output ends face the side of the substrate. The pipeline for supplying a mixed gas of methane and hydrogen is connected to the annular tube through the gas outlet.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] 1. The resonant cavity in this application adopts a cylindrical-conical gradient structure. The cylindrical section maintains a stable standing wave, and the conical section perturbs the reflection path through geometric gradient to suppress the attenuation of the edge electric field. In addition, the adjustable magnetic field coil actively controls the motion trajectory of the plasma, uniformly distributes the electric field, effectively eliminates the center-edge density difference, reduces the edge "extinguishing" phenomenon, improves the plasma coverage and uniformity, and provides a stable high-density active species distribution for the growth of diamond films.

[0021] 2. In this application, a top annular tube sprays a CH4 / H2 gas mixture to achieve uniform coverage of the primary carbon source over a large area of the substrate surface. Side arc-shaped grooves slowly release acetylene to compensate for the attenuation of active species at the edge, increasing the edge growth rate. Auxiliary nozzles inject high-concentration O2 / H2, removing gaseous byproducts through convection flushing while simultaneously repairing edge etching defects, significantly optimizing film density and lattice integrity and promoting smooth edge growth. This also significantly reduces the risk of localized over-deposition and reduces stress within the film.

[0022] 3. In the present application, the driving motor is started to drive the coating frame and the substrate to rotate synchronously, so that the substrate continuously changes position in the jet airflow, and alternately contacts the CH4 / H2 main source and acetylene / O2 / H2 auxiliary gas in multiple directions; the rotation causes the acetylene and O2 / H2 airflows to diffuse evenly along the edge of the substrate, suppressing local concentration peaks and lattice distortion; at the same time, the rotational motion enhances convection, improves reactant mass transfer and product discharge, and enhances the isotropic growth uniformity and surface smoothness of the film.

[0023] 4. In this application, the microchannels on the surface of the molybdenum plate below the substrate conduct heat quickly, reducing the temperature gradient in the deposition area and improving thermal uniformity; the copper plate has strong thermal conductivity, which can absorb and conduct heat from the molybdenum plate in time, inhibit the deformation caused by the thermal stress of the molybdenum plate, and ensure the stability of the substrate position; the nanocrystalline diamond (NCD) coating on the surface of the coating frame enhances the plasma corrosion resistance, effectively extends the service life of the equipment, and makes the entire cavity stable and reliable in long-term operation.

[0024] In summary, this application achieves uniform high-density plasma distribution through a cylindrical-conical resonant cavity and an adjustable magnetic field, multi-mode gas injection and substrate rotation synergistically compensate for the attenuation of edge active species and remove by-products, and multi-layer thermal management and materials synergistically ensure stable substrate positioning and equipment durability, which significantly improves the overall quality and efficiency of diamond film growth, while also increasing the growth rate and film density. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the overall axonometric structure of a large-size diamond microwave plasma growth device proposed in the present invention.

[0026] Figure 2 This is a schematic diagram of the plasma generator and transmission tube structure of a large-size diamond microwave plasma growth equipment proposed by the present invention.

[0027] Figure 3 This is a schematic diagram of the fixed rod and annular tube structure of a large-size diamond microwave plasma growth device proposed by the present invention.

[0028] Figure 4 This is a schematic diagram of the base and heat dissipation hole structure of a large-size diamond microwave plasma growth device proposed by the present invention.

[0029] Figure 5 This is a schematic diagram of the arc groove and escape hole structure of a large-size diamond microwave plasma growth device proposed by the present invention.

[0030] Figure 6 This is a schematic diagram of the drive motor and connecting rod structure of a large-size diamond microwave plasma growth device proposed by the present invention.

[0031] Figure 7 This is a schematic diagram of the half-section structure of the resonant cavity and protective frame of a large-size diamond microwave plasma growth device proposed in the present invention.

[0032] In the figure: 1 base, 2 gas delivery port, 3 sealing door, 4 resonant cavity, 5 vacuum window, 6 waveguide tube, 7 observation window, 8 control console, 9 plasma generator, 10 transmission tube, 11 fixing frame, 12 working frame, 13 fixing rod, 14 annular tube, 15 arc groove, 16 escape hole, 17 auxiliary nozzle, 18 air inlet, 19 heat dissipation hole, 20 coating frame, 21 molybdenum plate, 22 microchannel, 23 copper plate, 24 connecting rod, 25 drive motor, 26 magnetic field coil, 27 protection frame, 28 microwave tube. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0034] Reference Figures 1 to 7 A large-size diamond microwave plasma growth device includes a base 1, a cavity is opened inside the base 1, and a sealed door 3 is rotatably installed at the front end of the base 1. By opening the sealed door 3, the material in the cavity inside the base 1 can be taken out. The left and right sides of the base 1 are provided with gas ports 2 connected to the interior thereof. The gas ports 2 are used for routing various gas pipes. A plasma generator 9 is fixedly installed at the rear end of the base 1. The plasma generator 9 is a prior art and its specific structural design will not be repeated here. It is used to generate plasma used in subsequent production processes. A heat dissipation hole 19 is provided at the lower end of the base 1 for dissipating heat inside the cavity.

[0035] A resonant cavity 4 is fixedly mounted on one side of the top of the base 1. The resonant cavity 4 is cylindrical at its upper end and gradually transitions to a tapered shape at its lower end. An observation window 7 is fixedly mounted on the side of the resonant cavity 4 and communicates with the interior thereof. The observation window 7 is used to observe the interior of the resonant cavity 4. A vacuum window 5 is fixedly mounted on the top of the resonant cavity 4 and communicates with the interior thereof. A waveguide 6 is fixedly connected to the top of the vacuum window 5. A transmission tube 10 and a microwave tube 28 are fixedly connected to the top of the waveguide 6. The end of the transmission tube 10 remote from the waveguide 6 is connected to the output end of the plasma generator 9. The plasma generated by the plasma generator 9 enters the resonant cavity 4 in sequence through the transmission tube 10, the waveguide 6, and the vacuum window 5. The end of the microwave tube 28 remote from the waveguide 6 is connected to a microwave generator (not shown). The microwave generator is conventional, and its specific structural design will not be described in detail here. The microwave generator is used to generate microwaves, which enter the resonant cavity 4 through the waveguide 6 and the vacuum window 5. The resonant cavity 4 can adjust the standing wave pattern of the microwaves entering it, thereby improving the spatial distribution characteristics of the plasma.

[0036] A protective frame 27 is movably provided under the resonant cavity 4, and a cavity is formed between the protective frame 27 and the outer wall of the resonant cavity 4. A magnetic field coil 26 is provided inside the cavity and is sleeved on the outside of the resonant cavity 4. The magnetic field coil 26 can generate a magnetic field after being energized, thereby controlling the motion trajectory of the plasma inside the resonant cavity 4, avoiding uneven deposition caused by local energy concentration, suppressing plasma turbulence, and reducing disordered electron collisions.

[0037] A control console 8 is fixedly mounted on the other side of the top of the base 1. The control console 8 is provided with a display screen and various operation buttons for controlling the operation of the entire device.

[0038] A fixed frame 11 is fixedly installed in the cavity of the base 1, and the fixed frame 11 is located directly below the resonant cavity 4. A drive motor 25 is fixedly installed on the inner bottom wall of the fixed frame 11. The output end of the drive motor 25 is facing upward and is keyed to a connecting rod 24. A coating frame 20 is fixedly installed on the top of the connecting rod 24. The surface of the coating frame 20 is plated with a nanocrystalline diamond coating NCD. The nanocrystalline diamond coating can improve the plasma corrosion resistance of the coating frame 20. A molybdenum plate 21 and a copper plate 23 are placed in sequence from top to bottom inside the coating frame 20. The substrate is placed in the middle position of the molybdenum plate 21. The upper surface of the molybdenum plate 21 is provided with staggered microchannels 22. With the assistance of the microchannels 22, the molybdenum plate 21 can quickly conduct heat to the substrate during processing, and the copper plate 23 under the molybdenum plate 21 has strong thermal conductivity, which can absorb and conduct away the heat on the molybdenum plate 21 in time, and can further suppress the deformation caused by the thermal stress that may be generated in the molybdenum plate 21, so the molybdenum plate 21 will not deform due to heat changes, thereby affecting the position of the substrate.

[0039] A working frame 12 is detachably mounted on the top of the fixed frame 11. An arc-shaped groove 15 is provided on the inner side of the working frame 12. A sealing cover (not shown in the figure) is provided on the upper end of the arc-shaped groove 15. Multiple escape holes 16 are provided at equal intervals on one side of the arc-shaped groove 15. The multiple escape holes 16 are all facing the substrate side. An auxiliary nozzle 17 is also provided on the inner side of the working frame 12. The auxiliary nozzle 17 is symmetrically distributed with the arc-shaped groove 15. An air inlet 18 is provided on one side of the fixed frame 11. The pipeline for supplying acetylene first enters the air inlet 18 through the gas delivery port 2, and then is connected to the arc-shaped groove 15 through the air inlet 18, so that acetylene is ejected through the multiple escape holes 16. The pipeline for supplying high-concentration O2 / H2 gas first enters the gas delivery port 2, and then is connected to the auxiliary nozzle 17, so that O2 / H2 gas can be ejected from the auxiliary nozzle 17.

[0040] An annular tube 14 is provided above the working frame 12, and the annular tube 14 is fixedly connected to the inner top wall of the base 1 by a fixing rod 13. A plurality of nozzles are provided at equal intervals at the lower end of the annular tube 14. The nozzles are arranged at an angle with the output ends facing the substrate side. The pipeline for supplying CH4 / H2 mixed gas is connected to the annular tube 14 through the gas outlet 2, so that the CH4 / H2 mixed gas can be ejected from the nozzles.

[0041] When the present invention is in use, the sealing door 3 is opened, the substrate is placed in the middle position of the molybdenum plate 21, the sealing door 3 is closed, the gas pipe is connected to the gas outlet 2 on both sides of the base 1, and the plasma generator 9 is started through the control console 8. The generated plasma enters the waveguide 6 through the transmission tube 10, and microwaves are simultaneously injected into the waveguide 6 through the microwave generator.

[0042] After the microwave passes through the vacuum window 5 and enters the resonant cavity 4, the microwave standing wave mode is regulated to improve the spatial distribution characteristics of the plasma, thereby improving the quality and efficiency of diamond growth. The resonant cavity 4 here adopts a special design with a cylindrical upper end and a gradually transitioning to a conical lower end. The diameter of different areas of the cone changes in sections. The purpose of this design is: the cylindrical section provides a stable microwave standing wave mode, and the conical section adjusts the microwave reflection path through geometric gradient to suppress the attenuation of the edge electric field. In a traditional cylindrically symmetrical cavity, the microwave standing wave will form a distribution with a strong central electric field and a weak edge, resulting in a decrease in plasma density at the edge of the substrate and uneven growth; the conical or stepped structure will disturb the microwave propagation path, making the electric field distribution flatter; the phase difference of the edge reflection wave is offset by geometric asymmetry to reduce the "edge extinction" phenomenon of the plasma.

[0043] The magnetic field coil 26 wound around the lower end of the resonant cavity 4 can actively control the trajectory of the plasma, avoid uneven deposition caused by local energy concentration, suppress plasma turbulence, and reduce disordered electron collisions.

[0044] An annular tube 14 is located above the fixed frame 11, spraying a CH4 / H2 mixed gas onto the substrate. The edge of the working frame 12 is provided with an arcuate groove 15, with an escape hole 16 on one side. Acetylene is added to the groove 15 at appropriate times, allowing it to slowly escape from the escape hole 16 and contact the substrate. Opposite the groove 15, an auxiliary nozzle 17 is located to inject a high-concentration O2 / H2 mixed gas. Acetylene enters the gas inlet 18 through the gas supply port 2, and then enters the arcuate groove 15 from the gas inlet 18. The auxiliary nozzle 17 directly supplies the high-concentration O2 / H2 mixed gas through the side gas supply port 2. During operation, the drive motor 25 is activated, driving the coating frame 20 to rotate via the connecting rod 24, thereby simultaneously rotating the substrate at an appropriate speed. This design has the following advantages.

[0045] First: the CH4 / H2 mixed gas injected by the annular tube 14 can cover a large area of the substrate, ensuring a uniform supply of the main carbon source;

[0046] Second: The slow release of acetylene can compensate for the attenuation of edge plasma density and increase the edge growth rate;

[0047] Third: The O2 / H2 auxiliary injection on the side and the annular airflow on the top form a convection flushing to reduce the retention of gas phase by-products; at the same time, it plays the role of edge etching and defect repair;

[0048] Fourth, the rotation of the substrate at an appropriate speed allows the substrate to be more evenly exposed to the CH4 / H2 mixed gas and acetylene on the side. At the same time, after the acetylene is slowly released from the arc groove 15, it diffuses evenly to the edge with the rotation, avoiding lattice distortion caused by local excessive concentration. The O2 / H2 gas flow cooperates with the rotation to evenly etch the side of the substrate, inhibiting the formation of grain boundaries caused by three-dimensional growth.

[0049] The molybdenum plate 21 beneath the substrate is equipped with microchannels 22 on its surface to quickly dissipate reaction heat. The copper plate 23 beneath the molybdenum plate 21 has strong thermal conductivity, absorbing and dissipating heat from the molybdenum plate 21. This further suppresses deformation caused by thermal stress in the molybdenum plate 21. Therefore, the molybdenum plate 21 does not deform due to thermal fluctuations, thereby affecting the position of the substrate. The coating frame 20 is coated with a nanocrystalline diamond (NCD) coating to improve plasma corrosion resistance. The synergistic effect of these multiple materials significantly optimizes thermal management, mechanical stability, and corrosion resistance, thereby improving the quality and efficiency of diamond growth.

[0050] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A large-scale diamond microwave plasma growth device, comprising a base (1) and a control console (8) fixedly mounted on one side of the top of the base (1), wherein a cavity is provided inside the base (1), a sealing door (3) is rotatably mounted on the front end of the base (1), and gas delivery ports (2) communicating with the interior of the base (1) are provided on both the left and right sides of the base (1), characterized in that: A resonant cavity (4) is fixedly mounted on the other side of the top of the base (1); a vacuum window (5) communicating with the interior of the resonant cavity (4) is fixedly mounted on the top of the resonant cavity (4); a waveguide (6) is fixedly connected to the top of the vacuum window (5); a plasma generating mechanism is connected to one side of the waveguide (6), and a microwave generating mechanism is connected to the other side of the waveguide; A fixing frame (11) is fixedly installed in the cavity of the base (1), a coating frame (20) is provided inside the fixing frame (11), a driving mechanism is connected to the lower end of the coating frame (20), a molybdenum plate (21) and a copper plate (23) are placed in sequence from top to bottom inside the coating frame (20), and a substrate is placed in the middle of the molybdenum plate (21); A working frame (12) is detachably mounted on the top of the fixed frame (11); a first injection mechanism for outputting acetylene is provided on one side of the interior of the working frame (12); a second injection mechanism for outputting a mixed gas of oxygen and hydrogen is provided on the other side of the interior; and a third injection mechanism for outputting a mixed gas of methane and hydrogen is provided above the working frame (12).

2. The large-scale diamond microwave plasma growth equipment according to claim 1, characterized in that: The resonant cavity (4) adopts a structural design in which the upper end is cylindrical and the lower end gradually transitions to a cone. An observation window (7) communicating with the interior of the resonant cavity (4) is fixedly mounted on the side surface of the resonant cavity (4).

3. The large-size diamond microwave plasma growth equipment according to claim 1, characterized in that: The plasma generating mechanism comprises a transmission tube (10) fixedly connected to the waveguide tube (6); one end of the transmission tube (10) away from the waveguide tube (6) is connected to a plasma generator (9); and the plasma generator (9) is fixedly mounted on the rear end of the base (1).

4. The large-scale diamond microwave plasma growth equipment according to claim 3, characterized in that: The microwave generating mechanism comprises a microwave tube (28) fixedly connected to the waveguide tube (6); one end of the microwave tube (28) away from the waveguide tube (6) is connected to a microwave generator.

5. The large-scale diamond microwave plasma growth equipment according to claim 1, characterized in that: A protective frame (27) is movably provided below the resonant cavity (4), a cavity is formed between the protective frame (27) and the outer wall of the resonant cavity (4), and a magnetic field coil (26) is provided inside the cavity and is sleeved on the outside of the resonant cavity (4).

6. The large-scale diamond microwave plasma growth equipment according to claim 1, characterized in that: The driving mechanism comprises a driving motor (25) fixedly mounted on the inner bottom wall of the fixing frame (11), the output end of the driving motor (25) facing upward and key-connected to a connecting rod (24), the top end of the connecting rod (24) being fixedly connected to the coating frame (20).

7. The large-scale diamond microwave plasma growth equipment according to claim 6, characterized in that: The surface of the coating frame (20) is plated with a nanocrystalline diamond coating, and the upper surface of the molybdenum plate (21) is provided with staggered microchannels (22).

8. The large-scale diamond microwave plasma growth equipment according to claim 1, characterized in that: The first injection mechanism comprises an arc-shaped groove (15) provided on the inner side of the working frame (12), a sealing cover is provided at the upper end of the arc-shaped groove (15), a plurality of escape holes (16) are provided at equal intervals on one side of the arc-shaped groove (15), and the plurality of escape holes (16) are all directed toward the substrate side, an air inlet (18) is provided on one side of the fixing frame (11), and a pipeline for supplying acetylene is connected to the arc-shaped groove (15) through the air delivery port (2) and the air inlet (18).

9. The large-scale diamond microwave plasma growth equipment according to claim 8, characterized in that: The second injection mechanism comprises an auxiliary nozzle (17) arranged inside the working frame (12), the auxiliary nozzle (17) and the arc groove (15) are symmetrically distributed, and a pipeline for supplying a mixed gas of oxygen and hydrogen is connected to the auxiliary nozzle (17) through a gas delivery port (2).

10. The large-scale diamond microwave plasma growth equipment according to claim 9, characterized in that: The third injection mechanism comprises an annular tube (14), the annular tube (14) being fixedly connected to the inner top wall of the base (1) via a fixing rod (13), a plurality of nozzles being provided at equal intervals at the lower end of the annular tube (14), the nozzles being arranged in an inclined manner with the output ends facing one side of the substrate, and a pipeline for supplying a mixed gas of methane and hydrogen being connected to the annular tube (14) via a gas delivery port (2).

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