Microwave plasma chemical vapor deposition method for diamond synthesis

Abstract

The utility model relates to the device of manufacturing diamond with the method of introducing gas into reaction chamber or changing the airflow in reaction chamber as the characteristics, especially relates to a kind of diamond device made by microwave plasma chemical vapor deposition method.Microwave plasma chemical vapor deposition method diamond device made by the reaction cavity, reaction cavity includes cavity bottom plate and the main cavity of buckle in cavity bottom plate, the lower mouth of main cavity is provided with the annular stop along extending to the outer periphery of cavity bottom plate, more than three adjusting top silk is set on annular stop along, the inner end of adjusting top silk is used for with the outer peripheral surface of cavity bottom plate and stop cooperation, the coaxial degree of main cavity and cavity bottom plate can be adjusted by screwing each adjusting top silk.Movable main cavity by adjusting top silk, main cavity position can be more accurately adjusted, guarantee the coaxial degree between main cavity and cavity bottom plate, make that plasma sphere distributes evenly and form round on growth base platform, guarantee the quality of diamond made.

Description

Technical Field

[0001] This utility model relates to an apparatus for manufacturing diamond by means of introducing gas into a reaction chamber, and in particular to an apparatus for manufacturing diamond by microwave plasma chemical vapor deposition. Background Technology

[0002] Microwave plasma chemical vapor deposition (MPCVD) is the preferred method for preparing high-quality single-crystal diamond. The production apparatus required for diamond preparation using this method includes a main cavity, a cavity base plate, and a growth stage. The main cavity is mounted on the cavity base plate, and the growth stage is located on the cavity base plate and enclosed within the main cavity.

[0003] In the process of diamond fabrication using microwave plasma chemical vapor deposition (MPCVD), single-crystal diamond wafers are regularly arranged on a growth substrate. Microwaves create a strong electric field on the substrate, and a mixture of hydrogen and methane gas is excited above the substrate to form plasma spheres, which react with the single-crystal diamonds to deposit and grow the diamond. If the plasma spheres are not evenly distributed above the growth substrate, it will lead to uneven temperature distribution among the single-crystal diamond wafers. Excessive temperature differences will directly affect the synthesis quality of the single-crystal diamond. Ideally, the plasma spheres are flat and spherical. The cavity structure of the production apparatus and the assembly precision (mainly coaxiality) between the cavity and the substrate will affect the morphology of the plasma spheres. Therefore, ensuring the assembly precision of the cavity is crucial for improving the state and temperature distribution of the plasma spheres.

[0004] Because the production process requires the handling of single-crystal diamond wafers, the main cavity and the cavity base plate are designed to open and close. The main cavity can be opened and closed as needed, achieved through an external opening and closing mechanism. Due to this structure, the coaxiality of the main cavity and the cavity base plate must be strictly ensured during assembly to guarantee the uniform distribution and rounded shape of the plasma spheres above the growth substrate. However, existing production equipment simply relies on the inclined surfaces of the main cavity and the cavity base plate for mechanical engagement, making it impossible to measure or adjust the precision of the engagement. Some adjustments even rely solely on manually pushing and pulling the main cavity, lacking precise adjustment capabilities. Utility Model Content

[0005] The purpose of this invention is to provide a device for diamond production by microwave plasma chemical vapor deposition, so as to solve the problem that existing similar devices cannot adjust the coaxiality between the main cavity and the cavity base plate.

[0006] To solve the above problems, the microwave plasma chemical vapor deposition apparatus for diamond production of this invention adopts the following technical solution: A microwave plasma chemical vapor deposition (IPV) diamond fabrication apparatus includes a reaction chamber, which comprises a chamber base plate and a main cavity that is fastened to the chamber base plate. An annular retaining edge extending downwards to the outer periphery of the chamber base plate is provided at the lower edge of the main cavity. Three or more adjusting screws are circumferentially arranged on the annular retaining edge. The inner end of each adjusting screw is used to abut against the outer circumferential surface of the chamber base plate. The coaxiality of the main cavity and the chamber base plate can be adjusted by turning each adjusting screw.

[0007] Furthermore, the adjusting set screws are evenly distributed along the circumference of the annular stop.

[0008] Furthermore, the number of adjusting set screws is even.

[0009] Furthermore, the upper end of the outer peripheral surface of the cavity base plate is provided with a guide slope for guiding the main cavity when it is fastened to the cavity base plate.

[0010] Furthermore, the guiding slope is a conical surface.

[0011] Furthermore, the reaction chamber is equipped with a centering measurement fixture, which includes a measuring base and a displacement sensor mounted on the measuring base. The measuring base is provided with a positioning structure for engaging with the outer peripheral surface of the chamber base plate to align the measuring head of the displacement sensor with the center of the chamber base plate. An clearance interval is provided between the lower end of the main chamber and the bottom surface of the chamber base plate to avoid the positioning structure.

[0012] Furthermore, the positioning structure is formed by a V-shaped groove provided on the side of the measuring base near the bottom plate of the cavity when in use, and the measuring head of the displacement sensor is located on the axis of symmetry of the V-shaped groove.

[0013] Furthermore, the measuring base includes a positioning base plate and a sensor bracket disposed on the positioning base plate, the positioning structure is disposed on the positioning base plate, and the sensor bracket is detachably connected to the positioning base plate.

[0014] Furthermore, the sensor bracket is composed of an upright plate provided on the positioning base plate. The upright plate is fixedly installed on the positioning base plate by threaded fasteners provided on the positioning base plate. The bottom surface of the positioning base plate is provided with countersunk holes corresponding to the threaded fasteners.

[0015] Furthermore, the upright plate is provided with a sensor mounting hole for mounting the displacement sensor, and an adjustment slot is provided on the radial side of the sensor mounting hole. A clamping screw is provided at the adjustment slot to clamp or loosen the displacement sensor.

[0016] Beneficial Effects: This invention relates to an improved device for diamond production via microwave plasma chemical vapor deposition. The device utilizes an annular baffle at the lower edge of the main cavity, which covers the outer periphery of the cavity's base plate. Three or more adjusting screws circumferentially positioned along the upper edge of the annular baffle allow for adjustment of the main cavity's radial position. Because the main cavity is moved via these adjusting screws, its position can be more precisely controlled, ensuring coaxiality between the main cavity and the cavity's base plate. This results in uniform and rounded distribution of plasma spheres above the growth platform, guaranteeing the quality of the produced diamond. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an embodiment of the microwave plasma chemical vapor deposition apparatus for diamond production according to this utility model. Figure 2 yes Figure 1 A three-dimensional view (front) of the centering and measuring fixture; Figure 3 yes Figure 1 A three-dimensional view (back side) of the centering and measuring fixture; Figure 4 yes Figure 1 A schematic diagram showing the alignment and measurement fixtures and their fit with the base plate.

[0018] In the diagram: 1. Main cavity; 101. Annular retaining edge; 102. Adjusting set screw; 2. Cavity base plate; 201. Sealing ring groove; 3. Device frame; 4. Growth stage; 5. Single crystal diamond wafer; 6. Plasma sphere; 7. Centering and measuring fixture; 701. Displacement sensor; 702. Measuring head; 703. V-groove; 704. Positioning base plate; 705. Sensor bracket; 706. Adjusting slot; 707. Clamping screw; 708. Display. Detailed Implementation

[0019] The features and performance of this utility model will be further described in detail below with reference to specific embodiments.

[0020] In the process of preparing high-quality single-crystal diamond using microwave plasma chemical vapor deposition (MPCVD), the assembly accuracy of the reaction chamber in the diamond-making apparatus (hereinafter referred to as the diamond-making apparatus) is one of the important factors affecting the diamond quality and yield. Specifically, whether the main cavity 1 and the cavity base plate 2 of the reaction chamber are accurately aligned will greatly affect the diamond quality and yield. Therefore, if the main cavity 1 and the cavity base plate 2 can be accurately aligned, the diamond yield and quality can be improved to a certain extent. The diamond-making apparatus of this invention can adjust the radial position of the main cavity 1 relative to the cavity base plate 2 after the main cavity 1 and the cavity base plate 2 are fastened together, so as to ensure the precise alignment between the two and thus guarantee the quality of the diamond produced.

[0021] Based on the above inventive concept, the specific implementation of the microwave plasma chemical vapor deposition (CCVD) diamond fabrication apparatus of this utility model is as follows: like Figure 1 As shown, the microwave plasma chemical vapor deposition (PCCVD) diamond fabrication apparatus of this invention includes a reaction chamber. The reaction chamber provides the sealed space required for the reaction, thereby creating the necessary reaction environment. A typical structure of the reaction chamber includes a main chamber 1 and a chamber base plate 2. The chamber base plate 2 is a flat plate, which is placed horizontally on the apparatus frame 3 of the microwave plasma chemical vapor deposition diamond fabrication apparatus during use. The outer contour of the main chamber 1 is a stepped shaft shape, and the interior is hollow, also forming stepped holes. A growth stage 4 is provided in the reaction chamber. During diamond fabrication, a single-crystal diamond sheet 5 can be placed on the growth stage 4, and the single-crystal diamond sheet 5 is grown using the plasma spheres 6 above the growth stage 4. The arrangement structure of the growth stage 4 and the working principle of the reaction chamber are existing technologies, and therefore will not be described in detail here.

[0022] During the diamond preparation process, the main cavity 1 is attached to the cavity base plate 2. To achieve a sealed fit between the main cavity 1 and the cavity base plate 2, a sealing ring groove 201 is provided on the top surface of the cavity base plate 2 corresponding to the opening edge of the main cavity. A sealing ring can be installed in the sealing ring groove 201 to seal the mating position between the main cavity 1 and the cavity base plate 2. In order to accurately adjust the horizontal position of the main cavity 1 after it is attached to the cavity base plate 2, an annular retaining edge 101 extending downward to the outer periphery of the cavity base plate is provided at the lower edge of the main cavity 1. The annular retaining edge 101 is coaxial with the main cavity 1. When the main cavity 1 is attached to the cavity base plate 2, the annular retaining edge 101 will cover the outer periphery of the cavity base plate 2.

[0023] Three or more adjusting screws 102 are circumferentially arranged on the annular retaining edge 101. The inner end of each adjusting screw 102 is used to abut against the outer circumferential surface of the cavity base plate 2. By turning each adjusting screw 102, the coaxiality between the main cavity 1 and the cavity base plate 2 can be adjusted. The adjusting screw 102 can be formed by parts with external threads, such as screws or threaded rods. When the adjusting screw 102 is turned, the cavity base plate 2 will be used as a support to drive the main cavity 1 to move towards the outer end of the adjusting screw 102.

[0024] To adjust the horizontal position of the main cavity 1, adjusting screws 102 need to be arranged circumferentially around the annular retaining edge 101, and there should be at least three of them. In practical applications, it is ideal for the adjusting screws 102 to be evenly distributed along the annular retaining edge 101. Figure 1 In the illustrated embodiment, eight adjusting screws 102 are arranged, and the angle between the line connecting two adjacent adjusting screws 102 and the center of the annular flange 101 is 45°. Of course, in other embodiments, the number of adjusting screws 102 can also be four, five, six, seven, nine, etc., which can be set according to actual needs.

[0025] When the number of adjusting screws 102 is even, the adjusting screws 102 will form a pair-to-pair structure in the radial direction of the annular retaining edge 101, thereby making it easier to control the direction of movement of the main cavity 1 during adjustment. Therefore, in a preferred embodiment, based on the structure of adjusting screws 102 being evenly distributed circumferentially along the annular retaining edge 101, the number of adjusting screws 102 is set to an even number.

[0026] Because the annular retaining edge 101 is provided on the main cavity 1, interference may occur between the annular retaining edge 101 and the cavity base plate 2 when the main cavity 1 is fastened to the cavity base plate 2. To prevent this from happening, in a preferred embodiment, the upper end of the outer peripheral surface of the cavity base plate 2 is provided with a guide slope for guiding the main cavity when it is fastened to the cavity base plate. This guide slope can specifically adopt an arc-shaped surface or other structures, but considering the difficulty of processing, in a preferred embodiment, the guide slope is set as a conical surface.

[0027] While it is possible to determine whether the main chamber 1 of the reaction chamber and the bottom plate 2 of the chamber are aligned by visual inspection or by using ordinary measuring tools such as rulers, the accuracy of visual inspection is limited, and ordinary measuring tools also have inconveniences when used, such as the need to repeatedly adjust the position of the main chamber 1 and repeatedly measure.

[0028] To address the difficulty in determining the alignment between the main cavity 1 and the cavity base plate 2, in a preferred embodiment, an alignment measuring fixture 7 is provided for the reaction chamber. The alignment measuring fixture 7 includes a measuring base and a displacement sensor 701 mounted on the measuring base. The measuring base can be placed on a device frame 3 during use. A positioning structure is provided on the measuring base to engage with the outer circumferential surface of the cavity base plate 2, aligning the measuring head 702 of the displacement sensor 701 with the center of the cavity base plate 2. The positioning structure contacts the cavity base plate 2, ensuring the measuring head 702 is directly opposite the center of the cavity base plate 2. During use, the measuring head 702 can be coaxial with or parallel to the adjusting screw 102. Turning the adjusting screw 102 will cause the displacement sensor 701 to change its value in real time, facilitating real-time observation of the position of the main cavity 1. To ensure the positioning structure can contact the cavity base plate 2, a clearance interval is provided between the lower end of the main cavity 1 and the bottom surface of the cavity base plate 2 to avoid the positioning structure.

[0029] In a preferred embodiment, the positioning structure is formed by a V-shaped groove 703 provided on one side of the measuring base near the cavity bottom plate 2 during use. The measuring head of the displacement sensor 701 is located on the axis of symmetry of the V-shaped groove 703. Using the V-shaped groove 703 as the positioning structure has advantages such as simple structure and easy processing. However, in other embodiments, those skilled in the art will understand that the positioning structure can also be formed by providing protrusions at intervals on corresponding sides of the measuring base, so that the two protrusions are distributed at both ends of a chord of the cavity bottom plate 2.

[0030] To simplify the structure of the measuring base and achieve lightweight and portable effects, in a preferred embodiment, the measuring base includes a positioning base plate 704 and a sensor bracket 705 disposed on the positioning base plate 704. The positioning structure is disposed on the positioning base plate 704, and the sensor bracket 705 is detachably connected to the positioning base plate 704. In a more preferred embodiment, the sensor bracket 705 is composed of a vertical plate disposed on the positioning base plate 704. The vertical plate is fixedly installed on the positioning base plate 704 by threaded fasteners. The bottom surface of the positioning base plate 704 has countersunk holes corresponding to the threaded fasteners.

[0031] Although the measuring base in the above embodiments is configured to include a positioning base plate 704 and a sensor bracket 705, those skilled in the art should understand that in other embodiments, the positioning base plate 704 does not necessarily have to be a "plate" structure; for example, it can also be a frame structure, a block structure, etc. Regarding the sensor bracket, in some embodiments, the positioning base may not have a clearly visible bracket structure. For example, mounting holes are directly provided on the positioning base plate 704, and the displacement sensor 701 is mounted on the measuring base through the mounting holes. In this case, a part of the positioning base plate actually constitutes the sensor bracket.

[0032] like Figure 2 , 3 As shown, to facilitate the installation of the displacement sensor 701, the upright plate is provided with a sensor mounting hole for installing the displacement sensor. An adjustment slot 706 is provided on one radial side of the sensor mounting hole, and a clamping screw 707 is provided at the adjustment slot to clamp or loosen the displacement sensor. Although the above embodiment includes a sensor mounting hole and an adjustment slot 706, those skilled in the art should understand that the above structure is not the only structure for installing the displacement sensor. For example, in other embodiments, a positioning groove and a corresponding pressure plate can be provided on the top of the upright plate to install the displacement sensor by pressing it down with the pressure plate.

[0033] like Figure 4 As shown, when aligning the reaction chamber of the diamond-making device of this invention, the measuring head 702 can be compressed after contacting the measured position, and the compression amount is displayed by the alignment display 708 of the displacement sensor 701. In actual operation, the positioning base plate V-groove 703 of the alignment measuring fixture is pressed against the outer cylindrical edge of the cavity base plate 2. With the cavity base plate 2 as the reference, the displacement sensor measuring head 702 is made to abut against the outer cylinder of the main cavity 1. At this time, the display 708 displays a measurement value. In this way, the values ​​at the positions of the equal-divided adjusting screws of the main cavity cylinder 8 are measured sequentially. By comparing the measured values ​​and adjusting the adjusting screws, the difference between the maximum and minimum values ​​of the eight positions is made to be within the assembly standard range. At this point, the coaxial adjustment of the main cavity and the cavity base plate is completed, and the external opening and closing mechanism of the main cavity and the main cavity are fastened and locked in place. After the cavity alignment is completed, the adjusting screw can be removed. The threaded hole where the adjusting screw is installed can be used to pump helium to accurately determine the approximate location of the leak point at the sealing ring where the main cavity and the cavity base plate meet. Helium can be delivered to the sealing point between the main cavity and the cavity base plate relatively accurately through the threaded hole.

[0034] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. The patent protection scope of the present utility model shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present utility model shall also be included within the protection scope of the present utility model.

Claims

1. A microwave plasma chemical vapor deposition (IPD) apparatus for diamond fabrication, comprising a reaction chamber, wherein the reaction chamber includes a chamber base plate and a main cavity body fastened to the chamber base plate, characterized in that, The lower edge of the main cavity is provided with an annular retaining edge extending downward to the outer periphery of the cavity bottom plate. Three or more adjusting screws are provided circumferentially on the annular retaining edge. The inner end of the adjusting screw is used to abut against the outer peripheral surface of the cavity bottom plate. The coaxiality of the main cavity and the cavity bottom plate can be adjusted by turning each adjusting screw.

2. The apparatus for diamond fabrication by microwave plasma chemical vapor deposition according to claim 1, characterized in that, The adjusting set screws are evenly distributed along the circumference of the annular retaining edge.

3. The microwave plasma chemical vapor deposition apparatus for diamond production according to claim 2, characterized in that, The number of adjusting set screws is even.

4. The microwave plasma chemical vapor deposition apparatus for diamond production according to any one of claims 1-3, characterized in that, The upper end of the outer peripheral surface of the cavity bottom plate is provided with a guide slope for guiding the main cavity when it is fastened to the cavity bottom plate.

5. The microwave plasma chemical vapor deposition apparatus for diamond production according to claim 4, characterized in that, The guiding slope is a conical surface.

6. The microwave plasma chemical vapor deposition apparatus for diamond production according to any one of claims 1-3, characterized in that, The reaction chamber is equipped with a centering measurement fixture, which includes a measuring base and a displacement sensor mounted on the measuring base. The measuring base is provided with a positioning structure for engaging with the outer peripheral surface of the chamber base plate to align the measuring head of the displacement sensor with the center of the chamber base plate. An clearance interval is provided between the lower end of the main chamber and the bottom surface of the chamber base plate to avoid the positioning structure.

7. The microwave plasma chemical vapor deposition apparatus for diamond production according to claim 6, characterized in that, The positioning structure is formed by a V-shaped groove on the side of the measuring base near the bottom plate of the cavity when in use, and the measuring head of the displacement sensor is located on the axis of symmetry of the V-shaped groove.

8. The apparatus for preparing diamond by microwave plasma chemical vapor deposition according to claim 6, characterized in that, The measuring base includes a positioning base plate and a sensor bracket mounted on the positioning base plate. The positioning structure is mounted on the positioning base plate, and the sensor bracket is detachably connected to the positioning base plate.

9. The apparatus for diamond fabrication by microwave plasma chemical vapor deposition according to claim 8, characterized in that, The sensor bracket is composed of an upright plate provided on the positioning base plate. The upright plate is fixedly installed on the positioning base plate by threaded fasteners provided on the positioning base plate. The bottom surface of the positioning base plate is provided with countersunk holes corresponding to the threaded fasteners.

10. The microwave plasma chemical vapor deposition apparatus for diamond production according to claim 9, characterized in that, The upright plate is provided with a sensor mounting hole for mounting the displacement sensor. An adjustment slot is provided on the radial side of the sensor mounting hole, and a clamping screw is provided at the adjustment slot to clamp or loosen the displacement sensor.

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