A diamond vapor deposition apparatus using carbon dioxide as a carbon source

Abstract

The application provides a diamond vapor deposition device using carbon dioxide as a carbon source, and relates to the technical field of diamond vapor deposition. The device comprises a microwave system for generating microwaves, and a plasma reaction cavity comprising a cavity and a liftable substrate table. A vertically extending hollow cylinder is arranged in the middle of the cavity, the axis of the hollow cylinder is opposite to the substrate table, the top of the hollow cylinder is connected to the inner side wall of the cavity through a first flat plate, a plurality of first through holes are arranged on the first flat plate, the first through holes are connected to an air outlet through a pipeline, a boss is arranged below the substrate table, the boss is attached to the inner wall of the hollow cylinder during the lifting of the substrate table, and isolation is formed, and a connecting mechanism for maintaining the height of the boss is arranged between the boss and the first flat plate. The cavity is isolated into two parts, the reaction gas, i.e. carbon dioxide, is prevented from entering the position below the substrate table, and the limitation of the overlapping area is eliminated.

Description

Technical Field

[0001] This application relates to the field of diamond vapor deposition technology, and more particularly to a diamond vapor deposition apparatus that uses carbon dioxide as a carbon source. Background Technology

[0002] Currently, synthetic diamonds are typically produced using microwave plasma chemical vapor deposition (MPCVD) technology, which grows high-quality synthetic diamonds on the surface of a substrate material.

[0003] Against the backdrop of a global effort to address climate change, developing greenhouse gas capture and utilization technologies has become a key pathway to promote green and low-carbon development. Low-carbon biosynthesis technology using one-carbon greenhouse gases as raw materials is a typical carbon-negative technology. This paper explores a new path for the green synthesis of diamond using carbon dioxide as a carbon source through microwave plasma chemical vapor deposition. Achieving sustainable and environmentally friendly diamond production not only helps reduce greenhouse gas emissions but also enables resource recycling.

[0004] Meanwhile, in plasma chemical vapor deposition (PCD) equipment using carbon dioxide as a carbon source, the inability to improve the utilization rate of reactive gases is a significant problem. If there is a large space below the substrate stage, and reactive gases enter below the substrate stage, they cannot participate in the reaction and are discharged to the outside, directly leading to a large emission of greenhouse gases. For example, Chinese invention patent application CN116555735A proposes a plasma chemical vapor deposition system in which, during the vapor deposition process, the cavity is divided into two parts by a first baffle in the middle of the cavity and a second baffle on the top of the substrate stage to prevent reactive gases from entering below the substrate stage. However, this system still has the following technical problem: because the first and second baffles partially overlap in the vertical direction to form isolation. On the one hand, the isolation effect is directly related to the size of the overlapping area, which is limited by the inner diameter of the cavity, thus limiting the isolation effect. On the other hand, when the fastening mechanism that keeps the first and second baffles in contact works, the connecting piece is slid into the anti-detachment groove by the relative rotation of the first and second baffles. However, to maintain a good isolation effect, there will be a large friction between the first and second baffles, making it difficult to rotate. Conversely, if it is easy to rotate, the isolation effect will be unsatisfactory. Summary of the Invention

[0005] This application provides a diamond vapor deposition apparatus that uses carbon dioxide as a carbon source, in order to at least solve the above-mentioned technical problems existing in the prior art.

[0006] According to a first aspect of this application, a diamond vapor deposition apparatus using carbon dioxide as a carbon source is provided, comprising:

[0007] A microwave system for generating microwaves that enter a plasma reaction chamber and excite carbon dioxide into a plasma ball;

[0008] The plasma reaction chamber includes a chamber body and a liftable substrate stage;

[0009] The cavity is provided with an air inlet and an air outlet. The air inlet is used to introduce carbon dioxide. A vertically extending hollow cylinder is provided in the middle of the cavity. The axis of the hollow cylinder is directly opposite the substrate stage. The top of the hollow cylinder is connected to the inner wall of the cavity via a first plate. The first plate is provided with a plurality of first through holes. The first through holes are connected to the air outlet via pipes.

[0010] A boss is provided below the substrate stage. During the process of the substrate stage rising, the boss is in contact with the inner wall of the hollow cylinder to form an isolation. A connecting mechanism is provided between the boss and the first plate to maintain the height of the boss.

[0011] According to certain embodiments of the first aspect of this application, the microwave system includes a microwave source, a waveguide, a mode converter, and a three-screw impedance matcher; the microwave source generates microwaves, the three-screw impedance matcher matches the impedance, the microwaves are transmitted along the waveguide to the mode converter, and under the action of the mode converter, they enter the plasma reaction chamber and excite carbon dioxide into a plasma ball above the substrate stage.

[0012] According to certain embodiments of the first aspect of this application, the connecting mechanism includes:

[0013] An extension portion is provided on the side wall of the boss and extends outward;

[0014] A first connecting part is disposed on the upper side of the extension part. The first connecting part includes a vertically extending first slot. Several horizontally extending first sliding grooves are provided on the side wall of the first slot at the same height. A locking tongue and a first spring are slidably disposed in each first sliding groove. The first spring provides pressure to the locking tongue toward the center of the first slot. A first slope is provided at the end of the locking tongue facing the first slot.

[0015] The second connecting part is disposed on the lower side of the first plate. The second connecting part includes a connecting rod connected to the first plate. The connecting rod is directly opposite the first slot, and a locking strip is fixedly disposed at the lower end of the connecting rod. The edge of the locking strip is provided with a second slope that slopes downward. During the process of the substrate stage rising, the first slope and the second slope come into contact, causing the locking tongue to move in a direction away from the center of the first slot. The locking tongue then moves to the upper side of the locking strip, and the locking strip forms a limit on the height of the locking tongue.

[0016] According to certain embodiments of the first aspect of this application, an unlocking bar is slidably disposed on the connecting rod, and the edge of the unlocking bar is provided with an upwardly sloping third ramp; as the substrate stage continues to rise, the locking tongue moves to the upper side of the unlocking bar; as the substrate stage descends, the third ramp contacts the lower side of the locking tongue, the unlocking bar first slides downward until it fits against the locking bar, and then the third ramp causes the locking tongue to move in a direction away from the center of the first slot, and the locking tongue moves downward to the lower side of the locking bar, and the locking tongue disengages from the locking bar.

[0017] According to certain embodiments of the first aspect of this application, a second spring is provided between the locking bar and the unlocking bar for providing an upward force to the unlocking bar.

[0018] According to some embodiments of the first aspect of this application, at least one of the locking bar and the unlocking bar is provided with a receiving groove for accommodating the second spring when the locking bar and the unlocking bar are in contact.

[0019] According to some embodiments of the first aspect of this application, the boss is provided with an adjustment mechanism to adjust the lifting and lowering of the substrate stage according to the height of diamond growth.

[0020] According to some embodiments of the first aspect of this application, the bottom of the substrate stage is columnar, and the boss is sleeved on the outside of the substrate stage; the adjustment mechanism includes a second slide groove and a slide table;

[0021] The second groove is a vertically extending ring shape, with the upper half completely located inside the boss, and the lower half of the second groove having an opening on the inner wall of the boss.

[0022] The slide is a vertically extending ring, and is fixed to the periphery of the substrate stage by a connecting plate. The slide is slidably engaged with the upper half of the second slide groove. The bottom of the slide is provided with several third springs for providing upward force, and the top of the slide is provided with an airbag for providing downward force and an inflation assembly. The inflation assembly inflates and deflates the airbag to adjust the lifting and lowering of the substrate stage.

[0023] According to certain embodiments of the first aspect of this application, the method for adjusting the lifting and lowering of the substrate stage based on the height of diamond growth is as follows:

[0024] As the diamond begins to grow, the airbag is inflated at the initial inflation rate.

[0025] Set adjustment period and positive pressure tolerance and negative pressure tolerance ;

[0026] The total pressure applied to the slide by all the third springs is detected during each adjustment cycle. ;

[0027] Calculate the expected pressure value for the current adjustment cycle. ;

[0028]

[0029] in, For the number of third springs, The spring constant; This is the initial compression of the third spring; This is the initial time of the current adjustment cycle. The average height of diamond growth per unit time;

[0030] The measured total pressure The expected pressure value within the corresponding adjustment period The difference is obtained by subtracting. If the difference is greater than the positive pressure tolerance If the difference is less than the negative pressure tolerance, then reduce the inflation rate of the next adjustment cycle; If the inflation rate is increased, the inflation rate for the next adjustment cycle will be increased; otherwise, the inflation rate for the next adjustment cycle will remain unchanged.

[0031] According to some embodiments of the first aspect of this application, the boss is spliced ​​together at the lower half of the second groove.

[0032] Compared with the prior art, this application has the following advantages:

[0033] 1. In this application, during the rising of the substrate stage, the protrusion below the substrate stage enters the vertically extending hollow cylinder in the middle of the cavity and comes into contact with the inner wall of the hollow cylinder, thereby isolating the cavity into two parts and preventing the reactive gas, namely carbon dioxide, from entering the area below the substrate stage. Furthermore, as the substrate stage rises, the overlapping area of ​​the hollow cylinder and the protrusion gradually increases, and the isolation effect is enhanced, eliminating the limitation of the overlapping area.

[0034] 2. This application controls the inflation and deflation of the gasbag and adjusts the lifting and lowering of the substrate stage, thereby keeping the positional relationship between the diamond growth surface and the plasma ball relatively fixed, thus maintaining the uniformity of diamond growth quality.

[0035] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0036] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, in which:

[0037] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0038] Figure 1 A schematic diagram of the overall structure of this application is shown.

[0039] Figure 2 A schematic diagram of the plasma reaction chamber of this application in its working state is shown.

[0040] Figure 3 A schematic diagram of the plasma reaction chamber of this application is shown in the state of placing the substrate material.

[0041] Figure 4 It shows Figure 2 A magnified view of the connecting mechanism at point A.

[0042] Figure 5 A schematic diagram of the locking process of the connection mechanism of this application is shown.

[0043] Figure 6 A schematic diagram of the unlocking process of the connection mechanism of this application is shown.

[0044] Figure 7 It shows Figure 2 A magnified view of the initial state of the adjusting mechanism at point B.

[0045] Figure 8 A schematic diagram of the adjustment mechanism of this application adjusting the lowering of the substrate stage is shown.

[0046] Figure 9 A schematic diagram of the slide mounting structure of this application is shown.

[0047] Explanation of reference numerals in the attached figures:

[0048] 100. Microwave system; 101. Microwave source; 102. Waveguide; 103. Mode converter; 104. Three-screw impedance tuner; 105. Plasma sphere;

[0049] 200. Plasma reaction chamber; 201. Chamber body; 202. Air inlet; 203. Air outlet; 204. Hollow cylinder; 205. First plate; 206. First through hole; 2071. Branch pipe; 2072. Main pipe; 208. Observation window; 209. Discharge port;

[0050] 211. Substrate stage;

[0051] 31. Extension section;

[0052] 32. First connecting part;

[0053] 33. Second connecting part. Detailed Implementation

[0054] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0055] Example 1:

[0056] This embodiment provides a diamond vapor deposition apparatus that uses carbon dioxide as a carbon source. Please refer to [link / reference]. Figure 1 It includes a microwave system 100 and a plasma reaction chamber 200.

[0057] The microwave system 100 is used to generate microwaves, which enter the plasma reaction chamber 200 and excite the reaction gas, namely carbon dioxide, into a plasma ball 105.

[0058] Specifically, the microwave system 100 includes a microwave source 101, a waveguide 102, a mode converter 103, and a three-screw impedance tuner 104. The microwave source 101 generates microwaves, and the three-screw impedance tuner 104 matches the impedance to minimize reflected power. The microwaves travel along the waveguide 102 to the mode converter 103, and under the action of the mode converter 103, they enter the plasma reaction chamber 200, where carbon dioxide is excited into a plasma sphere 105 above the substrate stage.

[0059] The substrate material is placed in the center of the substrate stage, close to the lower edge of the plasma ball 105, so that diamond is grown on the surface of the substrate material.

[0060] Please refer to Figure 2 The plasma reaction chamber 200 includes a chamber 201 and a liftable substrate stage 211.

[0061] Specifically, the cavity 201 is provided with an air inlet 202 and an air outlet 203. The air inlet 202 is used to introduce carbon dioxide. A vertically extending hollow cylinder 204 is provided in the middle of the cavity 201. The axis of the hollow cylinder 204 is directly opposite the substrate stage 211, so the substrate stage 211 can slide into / out of the hollow cylinder 204 during the lifting and lowering process.

[0062] In order to fix the hollow cylinder 204, the top of the hollow cylinder 204 is connected to the inner wall of the cavity 201 via a first plate 205. The first plate 205 is provided with a plurality of first through holes 206. The first through holes 206 are connected to the air outlet 203 via pipes, thereby realizing the discharge of waste gas.

[0063] To facilitate observation of diamond growth inside the cavity 201, this embodiment provides an observation window 208 facing the substrate stage 211 on the side wall of the cavity 201 above the first plate 205.

[0064] The cavity 201 is also provided with a discharge port 209, which is located on the side wall of the cavity 1 below the first plate 205, and is used to place the substrate material 210 on the substrate stage 211.

[0065] It is worth mentioning that the pipeline includes several branch pipes 2071 and a main pipe 2072. The number of branch pipes 2071 corresponds to the number of first through holes 206, and the top of each branch pipe 2071 is connected to a first through hole 206, while the bottom of each branch pipe 2071 is connected to the main pipe 2072. The gas outlet 203 is located on the main pipe 2072 and extends to the outside of the cavity 201. An air pump can also be connected to the outside of the gas outlet 203 to extract the internal reaction gas.

[0066] A substrate material 210 is placed on the upper surface of the substrate stage 211. A boss 212 is provided below the substrate stage 211. During the process of the substrate stage 211 rising, the boss 212 is attached to the inner wall of the hollow cylinder 204, forming an isolation between the upper and lower parts of the cavity 201, preventing the reaction gas, namely carbon dioxide, from entering the lower part of the cavity 201, and improving the utilization rate of the reaction gas.

[0067] Please refer to Figure 3 Under normal conditions, the substrate stage 211 is in a low position, at which time the substrate material 210 is placed on the substrate stage 211 through the feeding port 209. Then the substrate stage 211 rises until it reaches the preset growth height, preferably with the substrate stage 211 level with the first plate 205, i.e. Figure 2 The state shown.

[0068] exist Figure 2 In the state shown, the diamond growth reaction can be carried out by introducing a reactive gas. During the reaction, it is necessary to maintain the boss 212 at this height. Therefore, a connecting mechanism is provided between the boss 212 and the first plate 205 to maintain the height of the boss 212.

[0069] Please refer to Figure 4 The connecting mechanism includes an extension portion 31, a first connecting portion 32, and a second connecting portion 33.

[0070] Please combine Figure 2 and Figure 4 The extension portion 31 is disposed on the side wall of the boss 212 and extends outward.

[0071] The first connecting portion 32 is disposed on the upper side of the extension portion 31. The first connecting portion 32 includes a vertically extending first slot 321. Several horizontally extending first sliding grooves 322 are provided on the side wall of the first slot 321 at the same height. A locking tongue 323 and a first spring 324 are slidably disposed in each first sliding groove 322. The first spring 324 provides pressure to the locking tongue 323 toward the center of the first slot 321, so that the end of the locking tongue 323 extends into the first slot 321. The end of the locking tongue 323 facing the first slot 321 is provided with a first inclined ramp 3231 that is inclined upward.

[0072] The second connecting part 33 is disposed on the lower side of the first plate 205. The second connecting part 33 includes a connecting rod 331 fixedly connected to the first plate 205. The connecting rod 331 is directly opposite the first slot 321, and a locking strip 332 is fixedly disposed at the lower end of the connecting rod 331. The edge of the locking strip 332 is provided with a downward-sloping second ramp 3321. Figure 5 As shown, during the rise of the substrate stage, the first ramp 3231 and the second ramp 3321 come into contact. Under the mutual squeezing force of the two, the locking tongue 323 moves in a direction away from the center of the first slot 321, and the locking tongue moves to the upper side of the locking bar 332, that is... Figure 4 In the corresponding state, the locking bar 332 limits the height of the locking tongue 323, thereby keeping the boss 212 at that height.

[0073] Meanwhile, in order to release the height restriction of the locking bar 332 on the bolt 323, this embodiment has an unlocking bar 333 slidably disposed on the connecting rod 331, and the edge of the unlocking bar 333 is provided with an upwardly sloping third ramp 3331. To unlock, in Figure 4 In this state, the boss 212 and the substrate stage 211 continue to rise. As the substrate stage 211 continues to rise, the locking tongue 323 moves to the upper side of the unlocking bar 333. At this time, the third ramp 3331 contacts the lower side of the locking tongue 323, pushing the substrate stage 211 downwards. Under the pushing action of the third ramp 3331, as... Figure 6 As shown, firstly, the unlocking bar 333 slides downwards until it is in contact with the locking bar 332. Then, the third ramp 3331 causes the locking tongue 323 to move in a direction away from the center of the first slot 321. The locking tongue 323 then moves downwards to the lower side of the locking bar 332. Figure 5In the corresponding state, the locking tongue 323 disengages from the locking bar 332, completing the unlocking process. At this time, the boss 212 and the substrate stage 211 can descend freely.

[0074] To prevent the unlocking bar 333 from interfering with the locking bolt 323 during the locking process, the unlocking bar 333 and the locking bar 332 need to have a certain gap in normal operation. In this embodiment, a second spring 334 is provided between the locking bar 332 and the unlocking bar 333 to provide an upward force to the unlocking bar 333; specifically, a compression spring is used here.

[0075] Meanwhile, to ensure that the locking strip 332 and the unlocking strip 333 can smoothly adhere during the unlocking process, avoiding obstruction from the second spring 334 between them, at least one of the locking strip 332 and the unlocking strip 333 is provided with a receiving groove 335. The receiving groove 335 is used to accommodate the second spring 334 when the locking strip 332 and the unlocking strip 333 are adhered. Preferably, in this embodiment, the receiving groove 335 is provided on the opposite side of the locking strip 332 and the unlocking strip 333.

[0076] Example 2:

[0077] During diamond growth, diamond is gradually deposited on the upper surface of the substrate material 210, causing the deposition surface to rise higher and higher. The position of the deposition surface relative to the plasma above changes, which to some extent affects the uniformity of diamond growth quality.

[0078] To avoid the above situation, this embodiment provides an adjustment mechanism in the boss 212 to adjust the lifting and lowering of the substrate stage according to the height of diamond growth.

[0079] For details, please refer to Figure 7 and Figure 9 The bottom of the substrate stage 211 is columnar, and the boss 212 is sleeved on the outside of the substrate stage 211. The boss 212 and the substrate stage 211 can slide up and down relative to each other.

[0080] The adjustment mechanism includes a second slide 41 and a slide table 42.

[0081] The second groove 41 is a vertically extending ring shape, with the upper half completely located inside the boss 212, and the lower half of the second groove 41 forming an opening 411 on the inner wall of the boss 212.

[0082] The slide 42 is a vertically extending ring, such as... Figure 9As shown, the slide 42 is fixed to the periphery of the substrate stage 211 via a horizontally arranged connecting plate 421. The slide 42 is slidably engaged with the upper half of the second slide groove 41. The connecting plate 421 extends from the opening 411 and connects to the substrate stage 211. The height of the opening 411 can be set according to actual conditions to meet the lifting and lowering of the substrate stage 211 relative to the boss 212.

[0083] The bottom of the slide 42 is provided with several third springs 43 to provide upward force, thereby lifting the substrate stage 211 in the initial state. The top of the slide 42 is provided with an airbag 44 to provide downward force and an inflation assembly 45. The inflation assembly 45 inflates and deflates the airbag 44 to adjust the lifting and lowering of the substrate stage 211. Specifically, as shown... Figure 8 As shown, as the diamond growth height increases, in order to make the diamond growth surface fit as closely as possible to the plasma ball 105, the inflation component 45 inflates the air bag 44, thereby adjusting the substrate stage 211 to descend relative to the boss 212.

[0084] It is worth mentioning that, in order to achieve the installation of the slide table 42, the boss 212 adopts a split design and is spliced ​​in the lower half of the second slide groove 41. During installation, the airbag 44 and the inflation component 45 are first installed in the upper half of the second slide groove 41, then the slide table 42 is placed in the upper half of the second slide groove 41, and finally the split bosses are connected by welding or bolts.

[0085] This embodiment further proposes a method for adjusting the height of the substrate stage according to the height of diamond growth, as follows:

[0086] S1, while the diamond begins to grow, inflate the airbag at the initial inflation rate;

[0087] S2, set the adjustment cycle and positive pressure tolerance. and negative pressure tolerance ;

[0088] S3, during each adjustment cycle, detects the total pressure applied to the slide by all the third springs. ;

[0089] It is worth mentioning that the total pressure F is detected by installing a pressure sensor between the third spring 43 and the slide 42.

[0090] S4, Calculate the expected pressure value for the current adjustment cycle. ;

[0091]

[0092] in, For the number of third springs, The spring constant; This is the initial compression of the third spring; This is the initial time of the current adjustment cycle. The average height of diamond growth per unit time is calculated from the average value of multiple test experiments.

[0093] S5, the measured total pressure The expected pressure value within the corresponding adjustment period The difference is obtained by subtracting. .

[0094] If the difference is greater than the positive pressure tolerance If the pressure is too high, the compression of the third spring is greater than expected, and the airbag 44 is over-inflated. To adjust to the expected state in the next cycle, the inflation rate should be reduced. Conversely, if the difference is less than the negative pressure tolerance... If the pressure difference is within the positive pressure tolerance, then increase the inflation rate for the next adjustment cycle; otherwise, increase the inflation rate within the positive pressure tolerance. and negative pressure tolerance In between, the inflation rate should remain unchanged for the next adjustment cycle.

[0095] Using the methods described above, the height of the substrate stage can be finely adjusted during diamond growth to adapt to the diamond's growth rate and ensure uniform growth quality.

[0096] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.

[0097] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0098] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A diamond vapor deposition apparatus using carbon dioxide as a carbon source, characterized in that, include: A microwave system for generating microwaves that enter a plasma reaction chamber and excite carbon dioxide into a plasma ball; The plasma reaction chamber includes a chamber body and a liftable substrate stage; The cavity is provided with an air inlet and an air outlet. The air inlet is used to introduce carbon dioxide. A vertically extending hollow cylinder is provided in the middle of the cavity. The axis of the hollow cylinder is directly opposite the substrate stage. The top of the hollow cylinder is connected to the inner wall of the cavity via a first plate. The first plate is provided with a plurality of first through holes. The first through holes are connected to the air outlet via pipes. A boss is provided below the substrate stage. During the process of the substrate stage rising, the boss is in contact with the inner wall of the hollow cylinder to form an isolation. A connecting mechanism is provided between the boss and the first plate to maintain the height of the boss.

2. The diamond vapor deposition equipment using carbon dioxide as a carbon source according to claim 1, characterized in that, The microwave system includes a microwave source, a waveguide, a mode converter, and a three-screw impedance matcher. The microwave source generates microwaves, the three-screw impedance matcher matches the impedance, and the microwaves are transmitted along the waveguide to the mode converter. Under the action of the mode converter, the microwaves enter the plasma reaction chamber and excite carbon dioxide into a plasma ball above the substrate stage.

3. The diamond vapor deposition apparatus using carbon dioxide as a carbon source according to claim 1, characterized in that, The connecting mechanism includes: An extension portion is provided on the side wall of the boss and extends outward; A first connecting part is disposed on the upper side of the extension part. The first connecting part includes a vertically extending first slot. Several horizontally extending first sliding grooves are provided on the side wall of the first slot at the same height. A locking tongue and a first spring are slidably disposed in each first sliding groove. The first spring provides pressure to the locking tongue toward the center of the first slot. A first slope is provided at the end of the locking tongue facing the first slot. The second connecting part is disposed on the lower side of the first plate. The second connecting part includes a connecting rod connected to the first plate. The connecting rod is directly opposite the first slot, and a locking strip is fixedly disposed at the lower end of the connecting rod. The edge of the locking strip is provided with a second slope that slopes downward. During the process of the substrate stage rising, the first slope and the second slope come into contact, causing the locking tongue to move in a direction away from the center of the first slot. The locking tongue then moves to the upper side of the locking strip, and the locking strip forms a limit on the height of the locking tongue.

4. The diamond vapor deposition apparatus using carbon dioxide as a carbon source according to claim 3, characterized in that, An unlocking bar is slidably mounted on the connecting rod, and the edge of the unlocking bar is provided with a third upward-sloping ramp. As the substrate stage continues to rise, the locking tongue moves to the upper side of the unlocking bar. As the substrate stage descends, the third ramp contacts the lower side of the locking tongue. First, the unlocking bar slides downward until it fits against the locking bar. Then, the third ramp causes the locking tongue to move in a direction away from the center of the first slot. The locking tongue then moves downward to the lower side of the locking bar, and the locking tongue disengages from the locking bar.

5. The diamond vapor deposition apparatus using carbon dioxide as a carbon source according to claim 4, characterized in that, A second spring is provided between the locking bar and the unlocking bar to provide an upward force to the unlocking bar.

6. The diamond vapor deposition apparatus using carbon dioxide as a carbon source according to claim 5, characterized in that, At least one of the locking bar and the unlocking bar is provided with a receiving groove, which is used to receive the second spring when the locking bar and the unlocking bar are in contact.

7. The diamond vapor deposition apparatus using carbon dioxide as a carbon source according to claim 1, characterized in that, The boss is equipped with an adjustment mechanism to adjust the height of the substrate stage according to the height of diamond growth.

8. The diamond vapor deposition apparatus using carbon dioxide as a carbon source according to claim 7, characterized in that, The bottom of the substrate stage is columnar, and the boss is sleeved on the outside of the substrate stage; the adjustment mechanism includes a second slide groove and a slide table; The second groove is a vertically extending ring shape, with the upper half completely located inside the boss, and the lower half of the second groove having an opening on the inner wall of the boss. The slide is a vertically extending ring, and is fixed to the periphery of the substrate stage by a connecting plate. The slide is slidably engaged with the upper half of the second slide groove. The bottom of the slide is provided with several third springs for providing upward force, and the top of the slide is provided with an airbag for providing downward force and an inflation assembly. The inflation assembly inflates and deflates the airbag to adjust the lifting and lowering of the substrate stage.

9. The diamond vapor deposition apparatus using carbon dioxide as a carbon source according to claim 8, characterized in that, The method for adjusting the height of the substrate stage according to the diamond growth height is as follows: As the diamond begins to grow, the airbag is inflated at the initial inflation rate. Set adjustment period and positive pressure tolerance and negative pressure tolerance ; The total pressure applied to the slide by all the third springs is detected during each adjustment cycle. ; Calculate the expected pressure value for the current adjustment cycle. ; in, For the number of third springs, The spring constant; This is the initial compression of the third spring; This is the initial time of the current adjustment cycle. The average height of diamond growth per unit time; The measured total pressure The expected pressure value within the corresponding adjustment period The difference is obtained by subtracting. If the difference is greater than the positive pressure tolerance If the difference is less than the negative pressure tolerance, then reduce the inflation rate of the next adjustment cycle; If the inflation rate is increased, the inflation rate for the next adjustment cycle will be increased; otherwise, the inflation rate for the next adjustment cycle will remain unchanged.

10. The diamond vapor deposition apparatus using carbon dioxide as a carbon source according to claim 8, characterized in that, The boss is formed by splicing together the lower half of the second slide groove.

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