Square MPCVD resonant cavity and MPCVD equipment

Abstract

According to the square MPCVD resonant cavity and the MPCVD equipment provided by the invention, the four side panels which are movably designed are adopted, and each side panel extends or retracts between the upper cavity cover and the bottom plate structure to change the side length of the resonant cavity, so that more microwave modes can be focused in the central area of the resonant cavity; the composition of an electric field mode above the deposition area is changed by adjusting the side length of the side panel, accurate regulation and control of electric field distribution of the deposition area are achieved, and better deposition rate, material quality and deposition uniformity are achieved.

Description

Technical Field

[0001] The present application relates to the technical field of microwave plasma chemical deposition, and in particular to a square MPCVD resonant cavity and MPCVD equipment. Background Art

[0002] Microwave Plasma Chemical Vapor Deposition (MPCVD) is an important technology for preparing high-quality diamond materials. It decomposes chemical vapor substances under the stimulation of microwave electric fields under low pressure and high temperature conditions and deposits them on a substrate. It has the advantages of high efficiency, uniformity and controllability. MPCVD technology is widely used in materials science, surface engineering, electronic devices and optical devices.

[0003] The current MPCVD resonant cavities are cylindrical and square. Compared with the cylindrical MPCVD resonant cavity, the square MPCVD resonant cavity can achieve more precise control of the microwave field superposition mode; however, the existing square MPCVD resonant cavity cannot be adjusted according to the different needs of the electric field distribution in the deposition area of ​​the resonant cavity, which affects the adjustable performance of the MPCVD equipment and limits the flexible application of MPCVD technology in the preparation of diamond materials. Utility Model Content

[0004] The purpose of this application is to solve one of the above-mentioned technical defects and provide a square MPCVD resonant cavity and MPCVD equipment that can adjust the side length and improve the uniformity of the electric field distribution in the deposition area of ​​the square MPCVD resonant cavity.

[0005] A square MPCVD resonant cavity comprises an upper cavity cover, a bottom plate structure, and four movable side panels; wherein each side panel is connected between the upper cavity cover and the bottom plate structure, and the center of the bottom plate structure is the center of the resonant cavity;

[0006] The upper edge of each side panel is sealed to the upper cavity cover, the lower edge is sealed to the bottom plate structure, and the contact portion between the two side panels is sealed;

[0007] Each side panel is extended or contracted between the upper cavity cover and the bottom plate structure to change the side length of the resonant cavity.

[0008] In one embodiment, the first end of the side panel is perpendicular to the plane of the other side panel, and the second end of the side panel is connected to a moving device; wherein the moving device is used to drive the side panel to move.

[0009] In one embodiment, a hollow turbine is provided at the lower portion of the base plate structure;

[0010] The moving device of each side panel is connected to a worm with the same structure, and each worm is respectively engaged with a turbine; wherein each worm rotates to drive the turbine to rotate.

[0011] In one embodiment, the side panels are provided in a foldable structure that is retractable in a vertical direction.

[0012] In one embodiment, the base plate structure includes: a lifting plate and a lifting mechanism for driving the lifting plate to adjust its height position.

[0013] In one embodiment, a vacuum flange interface is provided on the top of the upper cavity cover for installing a coupler for detecting microwave characteristics.

[0014] In one embodiment, a sealing ring groove is provided at the edge of the side panel, and an X-shaped rubber ring is used to seal the sealing ring groove.

[0015] In one embodiment, the side length adjustment range of the side panel can be 240mm-260mm, and the height adjustment range of the lifting plate is about 110mm-120mm.

[0016] An MPCVD device comprises: the square MPCVD resonant cavity, a microwave source and a base; wherein a microwave feed port is provided at the center of the bottom plate structure, and the microwave source feeds microwaves into a deposition area in the square MPCVD resonant cavity through the microwave feed port.

[0017] In one embodiment, the microwave source is used to feed three microwave modes: TM021, TM031, and TM011.

[0018] The technical solution of the above-mentioned square MPCVD resonant cavity and MPCVD equipment adopts four side panels of movable design. Each side panel is extended or contracted between the upper cavity cover and the bottom plate structure to change the side length of the resonant cavity, so that more microwave modes can be focused in the central area of ​​the resonant cavity. By adjusting the side length of the side panel, the composition of the electric field mode above the deposition area can be changed, thereby realizing precise control of the electric field distribution in the deposition area and achieving better deposition rate, material quality and deposition uniformity.

[0019] Additional aspects and advantages of the present application will be given in part in the following description, which will become apparent from the following description, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0021] Figure 1Schematic diagram of a square MPCVD resonant cavity structure according to an embodiment;

[0022] Figure 2 is a cross-sectional view of a resonant cavity according to an embodiment;

[0023] Figure 3 is a schematic diagram of the side panel structure of an embodiment;

[0024] Figure 4 is a perspective view of a square MPCVD resonant cavity according to an embodiment;

[0025] Figure 5 1 is a schematic diagram of the bottom view structure of a square MPCVD resonant cavity according to an embodiment;

[0026] Figure 6 is a schematic diagram of an example sealing structure;

[0027] Figure 7 is a schematic structural diagram of an MPCVD device according to an embodiment;

[0028] Figure 8 This is a schematic diagram of an example of the superposition of multiple microwave modes. DETAILED DESCRIPTION

[0029] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and are not to be construed as limiting the present application.

[0030] Those skilled in the art will understand that, unless otherwise stated, the singular forms "a," "an," "the," and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of this application refers to the presence of the stated features, integers, steps, and operations, but does not preclude the presence or addition of one or more other features, integers, steps, and operations.

[0031] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0032] refer to Figure 1 As shown, Figure 1This is a schematic diagram of a square MPCVD resonant cavity structure of an embodiment. The overall structure is a square design including: an upper cavity cover 11, a bottom plate structure 12 and four side panels 13 of a movable design; each side panel 13 is connected between the upper cavity cover 11 and the bottom plate structure 12, and the center of the bottom plate structure 12 is the center of the square MPCVD resonant cavity 01; as shown in FIG. Figure 2 As shown, Figure 2 This is a cross-sectional view of a resonant cavity of an embodiment, in which the four side panels 13 are subdivided into numbers 131, 132, 132, and 134; the length of each side panel 13 can be adjusted; the upper edge of each side panel 13 is sealed to the upper cavity cover 11, the lower edge is sealed to the bottom plate structure 12, and the contact parts between the two side panels 13 are sealed.

[0033] During use, each side panel 13 extends or contracts between the upper cavity cover 11 and the bottom plate structure 12 to change the side length of the square MPCVD resonant cavity 01, so that the side length of the side panel 13 of the square MPCVD resonant cavity 01 can be increased or decreased according to needs during use.

[0034] As in the solution of the above embodiment, four side panels 13 of movable design are adopted. Each side panel 13 is extended or contracted between the upper cavity cover 11 and the bottom plate structure 12 to change the side length of the resonant cavity and adjust the boundary size of the square MPCVD resonant cavity 01. The energy ratio of the various controllable microwave modes fed into the deposition area in the resonant cavity can be adjusted, so that the central area of ​​the square MPCVD resonant cavity 01 can focus more microwave modes, thereby regulating the composition of the electric field mode above the deposition area and realizing precise control of the electric field distribution in the deposition area.

[0035] In one embodiment, the side panel 13 can also be configured as a folding structure, such as Figure 3 As shown, Figure 3 It is a schematic diagram of the side panel structure of an embodiment. In the vertical direction, the side panel 13 can be designed as a telescopic structure. The side panel 13 shown in the figure is composed of two parts, a side panel 13-1 and a side panel 13-2. The side panel 13-1 is nested in the side panel 13-2 and can be designed to be telescopic. In this way, the height of the side panel 13 can be adjusted in the vertical direction, thereby increasing the range of adjusting the height position of the bottom plate structure 12, thereby making the square MPCVD resonant cavity 01 more applicable.

[0036] In one embodiment, the first end 13a of each side panel 13 of the square MPCVD resonant cavity 01 is perpendicular to the plane of another side panel 13, and the second end 13b of the side panel 13 is connected to the moving device 130, wherein the moving device 130 is used to drive the side panel 13 to move.

[0037] In one embodiment, a hollow turbine 30 is provided at the lower part of the base plate structure 12, and the moving device 130 of each side panel 13 is connected to a worm 31 with the same structure. Each worm 31 is respectively engaged with the turbine 30. The moving device 130 drives each worm 31 to rotate, and at the same time, the turbine 30 also rotates to control the equal-time and equal-distance movement of each side panel 13, ensuring that each side panel 13 of the square MPCVD resonant cavity 01 is completely consistent when the side length changes.

[0038] like Figure 4 and Figure 5 As shown, Figure 4 is a three-dimensional diagram of a square MPCVD resonant cavity according to an embodiment. Figure 5 It is a bottom-view structural diagram of a square MPCVD resonant cavity of an embodiment; the structure shown in the figure is the key structural part of the side panels 13 and the bottom plate structure 12 of the square MPCVD resonant cavity 01. Four side panels 13 are movable between the upper cavity cover 11 and the bottom plate structure 12 of the square MPCVD resonant cavity 01. A hollow turbine 30 is provided at the lower part of the bottom plate structure 12 to respectively control the worm 31 of the four side panels 13. Each worm 31 is subdivided and numbered 311, 312, 313, and 314; each worm 31 rotates under the drive of the corresponding moving device 130.

[0039] During use, the four side panels 13 of the square MPCVD resonant cavity 01 are moved simultaneously in four directions through the turbine 30 and the worm 31. The moving device 130 can drive the worm 31 to rotate through the motor. At the same time, the turbine 30 can use a stepper motor and a reducer to control the rotation to ensure that the side panels 13 are at equal times and distances, thereby avoiding deviations in the boundary changes of the square MPCVD resonant cavity 01 and ensuring the stability of the square MPCVD resonant cavity 01 during the adjustment process. During the adjustment process, each side panel 13 is controlled to move slowly to maintain the sealing stability of the square MPCVD resonant cavity 01.

[0040] In one embodiment, Figure 4 As shown, the bottom plate structure 12 of the square MPCVD resonant cavity 01 of the present application is provided with a lifting plate 121 and a lifting mechanism 122, which are used to control the height position of the bottom of the resonant cavity to adjust the eigenfrequency of the square MPCVD resonant cavity 01. The lifting plate 121 can be driven to rise and fall by the lifting mechanism 122 under the turbine 30, thereby realizing the regulation of the eigenfrequency of the square MPCVD resonant cavity 01 and offsetting the influence of the moving distance of the side panel 13 on the eigenfrequency.

[0041] In one embodiment, Figure 4As shown, a vacuum flange interface 111 is provided on the top of the upper cavity cover 11 of the square MPCVD resonant cavity 01 of the present application. In addition to being used as an observation window, the vacuum flange interface 111 can also be used to connect a coupler. The coupler can be used to detect the microwave characteristics in the square MPCVD resonant cavity 01 after the side length of each side panel 13 changes.

[0042] For example, the coupler can be an electric field coupler, a magnetic field coupler, etc., to detect the microwave characteristics in the square MPCVD resonant cavity 01 after the position of the lifting plate 121 changes, and to verify the rationality of the moving distance.

[0043] As in the technical solution of the above embodiment, the four side panels 13 of the square MPCVD resonant cavity 01 are moved by the worm 31 and turbine 30 structure, and the height position adjustment of the lifting plate 121 at the bottom of the square MPCVD resonant cavity 01 is coordinated to achieve deposition requirements for different types of diamonds. It can be quickly adjusted during use without replacing the square MPCVD resonant cavity 01 or reprocessing it, which greatly improves the diamond deposition efficiency.

[0044] In one embodiment, a sealing ring groove 33 is provided on the edge of the side panel 13 of the square MPCVD resonant cavity 01 of the present application, and an X-shaped rubber ring 34 is used to seal the sealing ring groove 33 to achieve sliding friction sealing between each side panel 13 and between the upper cavity cover 11 and the bottom plate structure 12.

[0045] like Figure 6 As shown, Figure 6 This is a schematic diagram of an example sealing structure. X-shaped rubber rings 34 are used to achieve sliding friction sealing between each of the four side panels 13 and between them and the upper cavity cover 11 and the bottom plate structure 12. Sealing ring grooves 33 are set on the four side panels 13, which surround the four side panels 13 respectively to achieve sealing with the X-shaped sealing ring 34. The use of the X-shaped sealing ring has the advantages of more contacts, minimum compression deformation, and smaller friction. It has strong damage resistance during reciprocating motion and can achieve a more reliable dynamic sealing effect.

[0046] Preferably, in order to form a more reliable sealing effect and better maintain the air pressure stability inside the square MPCVD resonant cavity 01, a combined sealing structure can also be used, such as Figure 6 As shown, retaining rings 35 made of polytetrafluoroethylene or nylon are provided on both sides of the X-shaped sealing ring 34 to limit the position of the sealing ring, thereby further improving the sealing effect.

[0047] An embodiment of the MPCVD apparatus is described below.

[0048] like Figure 7 As shown, Figure 7It is a schematic diagram of the structure of an MPCVD device of an embodiment; the figure shows a perspective view, and the MPCVD device 100 structure includes a square MPCVD resonant cavity 01, a microwave source 02 and a base 14; a gas injection port 112 is provided on the square MPCVD resonant cavity 01, and the microwave source 02 feeds microwaves into the deposition area through a microwave feed port 120; the base 14 is used to carry materials such as diamond; each side panel 13 of the square MPCVD resonant cavity 01 can be adjusted in length or the bottom plate structure 12 can be adjusted in height.

[0049] For example, the upper cavity cover 11 may also be provided with a gas injection port 112. A microwave feed port 120 is provided at the center of the bottom plate structure 12 for feeding microwaves into the square MPCVD resonant cavity 01. A base 14 is provided above the microwave feed port 120. The microwave feed port 120 is sealedly connected to the base 14, and diamond materials, etc., can be placed on the base 14.

[0050] For example, a plurality of microwave modes can be fed into the square MPCVD resonant cavity 01 through the microwave source 02; the microwave modes can include three microwave modes, TM021, TM031 and TM011, with controllable microwave energy ratios. The electric field distribution uniformity in the deposition area in the square MPCVD resonant cavity 01 can be adjusted through different ratios.

[0051] like Figure 8 As shown, Figure 8 This is a schematic diagram of the superposition of multiple microwave modes as an example. As shown in the figure, the three microwave modes TM021, TM031 and TM011 are focused above the base 14, forming a strong electric field area; at the same time, the high electric field area avoids the area of ​​the microwave feed port 120, thereby avoiding the etching effect of the plasma on the microwave feed port 120, and also avoids the top area of ​​the upper cavity cover 11 above the deposition area, reducing the loss of microwave energy. By adjusting the side length of the square MPCVD resonant cavity 01, the superposition ratio of the three microwave modes TM021, TM031 and TM011 is controlled, thereby realizing the control of the electric field distribution above the deposition area, so that the electric field distribution uniformity of the deposition area in the square MPCVD resonant cavity 01 is better.

[0052] As in the technical solution of the above-mentioned embodiment, multiple microwave field superposition methods are adopted, and the square MPCVD resonant cavity 01 has boundaries of different characteristic sizes, so that microwave fields of multiple different modes are superimposed on the same deposition area, thereby realizing the superposition of microwaves with different electric field distributions above the deposition area, and generating a progressive superposition of multiple characteristic modes in the radial direction.

[0053] For example, in order to better realize the focusing capability of the square MPCVD resonant cavity 01, its side length adjustment range can be 240mm-260mm, and the height adjustment range is about 110mm-120mm; preferably, the gas injection port 112 is designed to be arranged in an array manner on the top of the upper cavity cover 11; preferably, a temperature measuring window 114 is also provided on the upper cavity cover 11; preferably, an observation window 115 can also be provided on the side panel 13 for observing the diamond growth condition.

[0054] During use, the diamond is placed on the base 14, and the square MPCVD resonant cavity 01 is evacuated using an air pump. For example, the pressure in the cavity can be evacuated to 10 -5 Pa, and then the reaction gas is injected into the square MPCVD resonant cavity 01 through the gas injection port 112. For example, a certain flow rate of H2 gas, such as 400sccm, 500sccm or 600sccm, etc., can be introduced, and a certain flow rate of CH4 gas, such as 10sccm, 20sccm or 30sccm, etc. can also be injected; then the microwave source 02 is turned on, and the microwaves of various modes generated by the microwave source 02, such as the three microwave modes of TM021, TM031 and TM011, are fed into the square MPCVD resonant cavity 01 to act on the reaction gas injected above the base 14, and the base 14 is maintained at the diamond growth temperature, such as 900℃, 1000℃ or 1100℃, etc., thereby exciting and generating a hydrogen plasma ball under the set microwave input power, temperature, gas pressure and gas flow conditions to deposit a diamond film.

[0055] The MPCVD equipment of the present application can be applied to diamond deposition. First, the intensity and uniformity of the electric field distribution in the deposition area are selected according to the diamond deposition requirements. If large-sized diamonds need to be deposited, or there are high requirements for the uniformity of the diamond material, for example: large-sized polycrystalline diamonds used for optical windows and heat sink materials; large-sized single-crystalline diamonds used for heat sink materials and electronic devices, or large-scale single-crystalline diamonds with stable quality control, etc.; it is necessary to improve the uniformity of the electric field distribution in the deposition area to further ensure the uniform distribution of plasma density, thereby improving the uniformity of diamond deposition. If smaller-sized diamonds need to be deposited, or there are high requirements for the deposition rate, for example: quickly depositing a small area of ​​single / polycrystalline diamond material in a short time, it is necessary to increase the intensity of the electric field distribution in the deposition area to further increase the plasma density and accelerate the etching rate of amorphous carbon, thereby improving the diamond deposition rate. Then, according to the requirements for the intensity and uniformity of the electric field distribution, the side lengths of the side panels 13 of the square MPCVD resonant cavity 01 and the height positions of the bottom plate structures 12 are appropriately adjusted, so as to regulate the proportion of microwave energy allocated to various microwave modes of the square MPCVD resonant cavity 01, such as regulating the energy ratio of the three microwave modes TM021, TM031 and TM011; thereby achieving the control of the electric field distribution in the deposition area; if it is necessary to enhance the central electric field intensity in the deposition area, the side length of the square MPCVD resonant cavity 01 can be reduced, and the proportion of microwave energy allocated to the TM021 mode can be increased; if it is necessary to improve the uniformity of the electric field distribution in the deposition area, the side length of the square MPCVD resonant cavity 01 can be increased, and the proportion of microwave energy occupied by the TM031 mode and the TM011 mode can be increased. When using the MPCVD equipment, the height position of the bottom plate structure 12 at the bottom of the square MPCVD resonant cavity 01 is adjusted to balance the effect of adjusting the side length of the square MPCVD resonant cavity 01 on the eigenfrequency of the square MPCVD resonant cavity 01, so that the eigenfrequency of the square MPCVD resonant cavity 01 remains at the operating frequency, for example: 2.45GHz, 915MHz, etc. The target side lengths of each side panel 13 and the target position of the bottom plate structure 12 can be calculated using an electromagnetic field simulation program; specifically, the electromagnetic field within the square MPCVD resonant cavity 01 is simulated and calculated using the electromagnetic simulation program to obtain a simulation effect diagram, and the corresponding target side length and target position of the bottom plate structure 12 are derived based on the simulation effect diagram.

[0056] For example, when adjusting the side length of the square MPCVD resonant cavity 01, the turbine 30 is first rotated, while simultaneously controlling the movement of the four side panels 13. By adjusting the side length of the square MPCVD resonant cavity 01, the superposition ratio of the microwave modes is regulated. According to the imported adjustment scheme, the height of the lifting plate 121 is then adjusted to adjust the eigenfrequency of the target characteristic mode of the square MPCVD resonant cavity 01 to the operating frequency, thereby achieving the purpose of adjusting the electric field distribution. After the MPCVD equipment is completed, the subsequent diamond growth process begins. After the growth process is completed, the side length of the new square MPCVD resonant cavity 01 and the height position of the bottom plate structure 12 are adjusted according to subsequent upgrade requirements.

[0057] The technical solution of the above embodiment can achieve precise control of the electric field distribution in the deposition area, obtain a more uniform electric field distribution and a more concentrated electric field excitation, thereby improving the deposition rate, material quality and deposition uniformity under limited microwave power.

[0058] The above description is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A square MPCVD resonant cavity (01), characterized in that: include: An upper cavity cover (11), a bottom plate structure (12), and four side panels (13) of a movable design; wherein each side panel (13) is respectively connected between the upper cavity cover (11) and the bottom plate structure (12), and the center of the bottom plate structure (12) is the center of the resonant cavity; The upper edge of each side panel (13) is sealed to the upper cavity cover (11), and the lower edge is sealed to the bottom plate structure (12), and the contact portion between the two side panels (13) is sealed; Each side panel (13) is extended or contracted between the upper cavity cover (11) and the bottom plate structure (12) to change the side length of the resonant cavity.

2. The square MPCVD resonant cavity (01) according to claim 1, characterized in that: The first end (13a) of the side panel (13) is perpendicular to the plane of the other side panel (13), and the second end (13b) of the side panel (13) is connected to a moving device (130); wherein the moving device (130) is used to drive the side panel (13) to move.

3. The square MPCVD resonant cavity (01) according to claim 2, characterized in that: A hollow turbine (30) is provided at the lower portion of the base plate structure (12); The moving device (130) of each side panel (13) is connected to a worm (31) with the same structure, and each worm (31) is respectively engaged with the turbine (30); wherein each worm (31) rotates to drive the turbine (30) to rotate.

4. The square MPCVD resonant cavity (01) according to claim 1, characterized in that: The side panels (13) are arranged in a foldable structure that is telescopic in the vertical direction.

5. The square MPCVD resonant cavity (01) according to claim 1, characterized in that: The bottom plate structure (12) comprises a lifting plate (121) and a lifting mechanism (122) for driving the lifting plate (121) to adjust the height position.

6. The square MPCVD resonant cavity (01) according to claim 1, characterized in that: A vacuum flange interface (111) is provided on the top of the upper cavity cover (11); the interface is used for installing a coupler for detecting microwave characteristics.

7. The square MPCVD resonant cavity (01) according to claim 1, characterized in that: The edge of the side panel (13) is provided with a sealing ring (34) groove (33), and an X-shaped rubber ring is used to seal the sealing ring (34) groove (33).

8. The square MPCVD resonant cavity (01) according to claim 7, characterized in that: The side length adjustment range of the side panel (13) can be 240mm-260mm, and the height adjustment range of the lifting plate (121) is approximately 110mm-120mm.

9. An MPCVD device (100), characterized in that include: The square MPCVD resonant cavity (01), microwave source (02) and base (14) according to any one of claims 1 to 8; wherein a microwave feeding port (120) is provided at the center of the bottom plate structure (12), and the microwave source (02) feeds microwaves into the deposition area in the square MPCVD resonant cavity (01) through the microwave feeding port (120).

10. The MPCVD device (100) according to claim 9, characterized in that The microwave source (02) is used to feed three microwave modes: TM021, TM031 and TM011.

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