Quartz bell jar type framework for diamond growth equipment based on MPCVD (Microwave Plasma Chemical Vapor Deposition) method

Abstract

The invention discloses a quartz bell jar type framework for diamond growth equipment based on an MPCVD method. The quartz bell jar type framework comprises a lower cavity, a molybdenum disc assembly; a middle cavity; the bottom of the quartz tube is embedded in the annular mounting groove; a gas supply ring structure; and the microwave waveguide structure is arranged in the middle of the air supply pipeline in a sleeving manner. According to the technical scheme, flange connection is omitted, so that assembling procedures are reduced, and assembling is easier; according to the technical scheme, only two sealing faces are reserved, the sealing performance is good, and the vacuum degree is high; according to the technical scheme, the assembly surfaces are few, the microwave waveguide is more stable, and the plasma in the cavity is more stable; meanwhile, due to the fact that the number of assembly parts is small, cost is saved.

Description

Technical Field

[0001] The invention relates to a diamond growth device using a MPCVD method, and in particular to a quartz bell-shaped structure used for a diamond growth device using a MPCVD method. Background Art

[0002] Microwave plasma chemical vapor deposition (MPCVD) technology is gaining more and more attention in the industry due to its many advantages such as high product quality, strong controllability and no pollution.

[0003] In the structure of conventional MPCVD equipment, microwaves are transmitted into the cavity through the coaxial section, and plasma is excited above the growth table for diamond synthesis. The cavity is divided into an upper cavity and a lower cavity, and the upper and lower cavities are isolated by a medium with a low dielectric constant (usually quartz glass). The upper cavity is at normal pressure, and the lower cavity is at low pressure, that is, a vacuum area. The two cavities are connected by a flange. The flange connection needs to be vacuum-tight and microwave-shielded at the same time.

[0004] However, the current connection flange ensures the airtightness of the lower cavity by adding a rubber ring under the glass, and the rubber ring is easily aged by microwaves; microwave leakage is prevented by increasing the number of screws between the two flanges, but too many flange screws are likely to cause damage to the quartz glass; in addition, the existing flange will form a strong electric field area at the top edge of the lower cavity (100), which will cause plasma instability. Therefore, it is necessary to develop a quartz bell-shaped structure for MPCVD diamond growth equipment that is simpler to assemble and has stable ions. After searching, no technical solution identical to the present invention was found. Summary of the invention

[0005] The main technical problem solved by the present invention is to provide a solution to one or more of the above-mentioned prior art problems.

[0006] In order to solve the above technical problems, a technical solution adopted by the present invention is: a quartz bell-shaped structure for diamond growth equipment based on MPCVD method, the innovation of which is:

[0007] A lower cavity, wherein an upper disc is provided on the top of the lower cavity, a lower disc is provided on the bottom, and a gasket is provided on the top of the upper disc;

[0008] a molybdenum disc assembly mounted on the backing ring;

[0009] A middle cavity, which is covered on the lower cavity and has a window on the top of the middle cavity for the molybdenum plate assembly to pass through; an annular cavity is formed between the inner wall of the middle cavity and the outer wall of the lower cavity; an air extraction pipeline is provided on the side of the middle cavity, and the air extraction pipeline is connected to the annular cavity; an annular mounting groove is provided on the top surface of the middle cavity, and the annular mounting groove is concentrically arranged with the window;

[0010] A quartz tube, the bottom of which is embedded in the annular mounting groove;

[0011] An air supply ring structure; the air supply ring structure includes an air supply pipeline, the axis of the air supply pipeline is provided with an air supply pipeline connecting the first section and the tail end of the air supply pipeline, the tail end of the air supply pipeline is provided with an upper cover, and the upper cover is coaxially arranged with the air supply pipeline; the upper cover includes a top layer and a bottom layer, the lower edge of the outer contour of the top layer is connected to the top of the quartz tube, the bottom layer is in an inverted frustum, the air supply pipeline passes through the center of the top layer and extends downward to the center of the bottom layer, the center of the bottom layer is provided with a notch, the bottom of the air supply pipeline is provided with an air supply disk, the air supply disk fills the notch, and the interior of the upper cover is hollowed out to form a cooling chamber; water inlet pipelines are respectively provided on both sides of the air supply pipeline in the air supply pipeline and a water outlet pipeline, a water inlet and an upper water outlet on the top side wall of the air supply pipeline, the upper water inlet is connected to the water inlet pipeline, the upper water outlet is connected to the water outlet pipeline, the upper water inlet is higher than the upper water outlet, a lower water outlet and a lower water inlet are provided on the bottom side wall of the air supply pipeline, the lower water outlet and the lower water inlet are both connected to the cooling chamber, and the lower water outlet is higher than the lower water outlet; a buffer cavity is also provided on the top of the air supply pipeline, a water inlet cavity and a water outlet cavity are provided in the buffer cavity, the upper water inlet is connected to the water inlet cavity, the upper water outlet is connected to the water outlet cavity, and the buffer cavity is provided with an external water inlet connected to the water inlet cavity and an external water outlet connected to the water outlet cavity;

[0012] A microwave waveguide structure is sleeved on the middle part of the air delivery pipeline.

[0013] In some embodiments, the molybdenum pan assembly includes a base mounted on top of the backing ring, a molybdenum pan seat disposed on top of the base, and a molybdenum pan body disposed on top of the molybdenum pan seat.

[0014] In some embodiments, an air extraction hole is provided on the molybdenum plate body, and the air extraction hole extends downward from the upper surface of the molybdenum plate body and passes through the molybdenum plate seat and the bottom bracket to communicate with the annular cavity.

[0015] In some embodiments, the microwave waveguide structure includes a transversely arranged waveguide cavity and a longitudinally arranged installation cavity, and the installation cavity is sleeved on the outside of the air delivery duct.

[0016] In some embodiments, a first annular sealing ring is provided in the annular mounting groove.

[0017] In some embodiments, a second sealing ring is provided at the connection between the upper cover and the quartz tube.

[0018] In some embodiments, a second cooling structure is also provided in the lower cavity, and the second cooling structure includes a cooling chamber arranged in the upper disc, a water inlet chamber and a water outlet chamber arranged in the lower cavity, a water inlet hole connected to the water inlet chamber, and a water outlet hole connected to the water outlet chamber, the top of the water inlet chamber is connected to the cooling chamber, and a water hole is provided in the cooling chamber, and the water hole is connected to the water outlet chamber.

[0019] The beneficial effects of the present invention are as follows: the present technical solution eliminates the flange connection, reduces the assembly process, and makes the assembly easier; the present technical solution only retains two sealing surfaces, has good sealing performance and high vacuum degree; the present technical solution has fewer assembly surfaces, and the microwave waveguide is more stable, making the plasma in the cavity more stable; at the same time, the present technical solution saves costs due to fewer assembly parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0021] Figure 1 It is a structural schematic diagram of a quartz bell-shaped structure for diamond growth equipment based on the MPCVD method of the present invention.

[0022] Figure 2 It is a cross-sectional schematic diagram of a quartz bell-shaped structure for diamond growth equipment based on the MPCVD method of the present invention.

[0023] Figure 3 It is a cross-sectional schematic diagram of a lower cavity of a quartz bell-shaped structure for diamond growth equipment based on the MPCVD method of the present invention. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] like Figures 1 to 3 As shown, the embodiment of the present invention includes:

[0026] A quartz bell-shaped structure for a diamond growth device based on MPCVD method, comprising:

[0027] A lower cavity 100, wherein an upper disc 120 is disposed on the top of the lower cavity 100, and a lower disc 110 is disposed on the bottom, and a gasket is disposed on the top of the upper disc 120;

[0028] A molybdenum disk assembly is mounted on a gasket; the molybdenum disk assembly includes a base 210 mounted on the top of the gasket, a molybdenum disk seat 220 arranged on the top of the base 210, and a molybdenum disk body 230 arranged on the top of the molybdenum disk seat 220, and an exhaust hole is provided on the molybdenum disk body 230, and the exhaust hole extends downward from the upper surface of the molybdenum disk body 230 and passes through the molybdenum disk seat 220 and the base 210 to communicate with the annular cavity 310.

[0029] The middle cavity 300 is covered on the lower cavity 100 and a window is provided on the top of the middle cavity 300 for the molybdenum plate assembly to pass through; an annular cavity 310 is formed between the inner wall of the middle cavity 300 and the outer wall of the lower cavity 100; an air extraction pipe 320 is provided on the side of the middle cavity 300, and the air extraction pipe 320 is connected to the annular cavity 310; an annular mounting groove 330 is provided on the top surface of the middle cavity 300, and the annular mounting groove 330 is concentrically arranged with the window;

[0030] A quartz tube 400, the bottom of which is embedded in the annular mounting groove 330;

[0031] An air supply ring structure 500; the air supply ring structure 500 includes an air supply pipeline, the axis of which is provided with an air supply pipeline 510 connecting the first section and the tail end of the air supply pipeline, the tail end of the air supply pipeline is provided with an upper cover 520, and the upper cover 520 is coaxially arranged with the air supply pipeline; the upper cover 520 includes a top layer and a bottom layer, the lower edge of the outer contour of the top layer is connected to the top of the quartz tube 400, the bottom layer is in the shape of an inverted truncated cone, the air supply pipeline passes through the center of the top layer and extends downward to the center of the bottom layer, the center of the bottom layer is provided with a notch, the bottom of the air supply pipeline is provided with an air supply disk, the air supply disk fills the notch, and the interior of the upper cover 520 is hollowed out to form a cooling chamber 521; a water inlet pipeline 530 and a water outlet pipeline 540 are respectively provided on both sides of the air supply pipeline 510 in the air supply pipeline, and a water inlet 551 is provided on the top side wall of the air supply pipeline and an upper water outlet 552, the upper water inlet 551 is connected to the water inlet pipeline 530, the upper water outlet 552 is connected to the water outlet pipeline 540, the upper water inlet 551 is higher than the upper water outlet 552, a lower water outlet 561 and a lower water inlet 562 are provided on the bottom side wall of the air delivery pipe, the lower water outlet 561 and the lower water inlet 562 are both connected to the cooling chamber 521, the lower water outlet 561 is higher than the lower water outlet 5 61; A buffer cavity 570 is also installed at the top of the air delivery pipe, and a water inlet cavity 571 and a water outlet cavity 572 are arranged in the buffer cavity 570, the upper water inlet 551 is connected to the water inlet cavity 571, the upper water outlet 552 is connected to the water outlet cavity 572, and the buffer cavity 570 is provided with an outer water inlet 573 connected to the water inlet cavity 571 and an outer water outlet 574 connected to the water outlet cavity 572;

[0032] The microwave waveguide structure 600 is sleeved in the middle of the air delivery pipeline.

[0033] The working principle of this technical solution is: first, the quartz tube 400 is evacuated through the exhaust pipe 320 and the exhaust hole, and then the quartz tube 400 is heated by the heating structure of the MPCVD equipment, and the gas required for growing diamonds is sent into the quartz tube 400 from the gas supply pipe 510. At the same time, the microwave waveguide structure 600 emits microwaves, and the microwaves enter the quartz tube 400 along the equipment to heat the gas to produce ions required for growing diamonds. The ions will continue to attach to the crystals placed on the molybdenum disk body 230 under high temperature and high pressure, thereby continuously growing. While heating, water is passed through the water supply pipe in the gas supply pipe for water circulation cooling to ensure that the temperature of the gas supply pipe is not too high.

[0034] In some embodiments, the microwave waveguide structure 600 includes a transversely arranged waveguide cavity and a longitudinally arranged installation cavity, and the installation cavity is mounted on the outside of the air supply pipe. This technical solution can make the microwave more stable.

[0035] In some embodiments, a first annular sealing ring is provided in the annular mounting groove 330 ; a second sealing ring is provided at the connection between the upper cover 520 and the quartz tube 400 . This technical solution can make the overall sealing better.

[0036] In some embodiments, a second cooling structure is further provided in the lower cavity 100, and the second cooling structure includes a cooling chamber 750 arranged in the upper disc 120, a water inlet chamber 710 and a water outlet chamber 720 arranged in the lower cavity 100, a water inlet hole 730 connected to the water inlet chamber 710, and a water outlet hole 740 connected to the water outlet chamber 720. The top of the water inlet chamber 710 is connected to the cooling chamber 750, and a drip hole 760 is provided in the cooling chamber 750, and the drip hole 760 is connected to the water outlet chamber 720. The present technical solution can cool the lower cavity 100 and the molybdenum disk assembly on the lower cavity 100 to avoid excessive temperature affecting crystal growth.

[0037] The technical solution eliminates flange connection, reduces assembly procedures, and makes assembly easier; the technical solution only retains two sealing surfaces, which provide good sealing and high vacuum; the technical solution has fewer assembly surfaces, and the microwave waveguide is more stable, making the plasma in the cavity more stable; at the same time, the technical solution saves costs due to fewer assembly parts.

[0038] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A quartz bell-shaped structure for diamond growth equipment based on MPCVD method, characterized in that: include A lower cavity (100), wherein an upper disc (120) is provided at the top of the lower cavity (100), and a lower disc (110) is provided at the bottom, and a gasket is provided at the top of the upper disc (120); a molybdenum disc assembly mounted on the backing ring; A middle cavity (300) is covered on the lower cavity (100) and a window is provided on the top of the middle cavity (300) for the molybdenum disk assembly to pass through; an annular cavity (310) is formed between the inner wall of the middle cavity (300) and the outer wall of the lower cavity (100); an air extraction pipe (320) is provided on the side of the middle cavity (300), and the air extraction pipe (320) is connected to the annular cavity (310); an annular mounting groove (330) is provided on the top surface of the middle cavity (300), and the annular mounting groove (330) is arranged concentrically with the window; A quartz tube (400), the bottom of which is embedded in the annular mounting groove (330); The air supply ring structure (500) comprises an air supply pipeline, the axis of the air supply pipeline is provided with an air supply pipeline (510) connecting the first section and the tail end of the air supply pipeline, the tail end of the air supply pipeline is provided with an upper cover (520), and the upper cover (520) is coaxially arranged with the air supply pipeline; the upper cover (520) comprises a top layer and a bottom layer, the lower edge of the outer contour of the top layer is connected to the top of the quartz tube (400), the bottom layer is in an inverted truncated cone shape, and the air supply pipeline The air supply pipe (520) is provided with an air supply plate at the bottom, and the air supply plate fills the gap. The interior of the upper cover (520) is hollowed out to form a cooling cavity (521). The air supply pipe (510) is provided with a water inlet pipe (530) and a water outlet pipe (540) on both sides of the air supply pipe (510). The air supply pipe has a water inlet (551) and an upper water outlet (552) on the top side wall. The water inlet (551) is in communication with the water inlet pipeline (530), the upper water outlet (552) is in communication with the water outlet pipeline (540), the upper water inlet (551) is higher than the upper water outlet (552), a lower water outlet (561) and a lower water inlet (562) are provided on the bottom side wall of the air delivery pipeline, the lower water outlet (561) and the lower water inlet (562) are both in communication with the cooling chamber (521), and the lower water outlet (561) is higher than the lower water outlet (561); A buffer cavity (570) is also arranged at the top of the air pipeline, and a water inlet cavity (571) and a water outlet cavity (572) are arranged in the buffer cavity (570); the upper water inlet (551) is in communication with the water inlet cavity (571), and the upper water outlet (552) is in communication with the water outlet cavity (572); the buffer cavity (570) is provided with an external water inlet (573) in communication with the water inlet cavity (571) and an external water outlet (574) in communication with the water outlet cavity (572); A microwave waveguide structure (600) is sleeved on the middle part of the air delivery pipeline.

2. The quartz bell-shaped structure for diamond growth equipment based on MPCVD method according to claim 1, characterized in that: The molybdenum plate assembly comprises a base (210) mounted on the top of the gasket, a molybdenum plate seat (220) arranged on the top of the base (210), and a molybdenum plate body (230) arranged on the top of the molybdenum plate seat (220).

3. The quartz bell-shaped structure for diamond growth equipment based on MPCVD method according to claim 2, characterized in that: The molybdenum plate body (230) is provided with an air extraction hole, which extends downward from the upper surface of the molybdenum plate body (230) and passes through the molybdenum plate seat (220) and the bottom bracket (210) to communicate with the annular cavity (310).

4. The quartz bell-shaped structure for diamond growth equipment based on MPCVD method according to claim 1, characterized in that: The microwave waveguide structure (600) comprises a transversely arranged waveguide cavity and a longitudinally arranged installation cavity, wherein the installation cavity is sleeved on the outside of the air delivery pipeline.

5. The quartz bell-shaped structure for diamond growth equipment based on MPCVD method according to claim 1, characterized in that: A first annular sealing ring is arranged in the annular mounting groove (330).

6. The quartz bell-shaped structure for diamond growth equipment based on MPCVD method according to claim 1, characterized in that: A second sealing ring is provided at the connection between the upper cover (520) and the quartz tube (400).

7. The quartz bell-shaped structure for diamond growth equipment based on MPCVD method according to claim 1, characterized in that: A second cooling structure is also provided in the lower cavity (100), the second cooling structure comprising a cooling chamber (750) provided in the upper disc (120), a water inlet chamber (710) and a water outlet chamber (720) provided in the lower cavity (100), a water inlet hole (730) connected to the water inlet chamber (710), and a water outlet hole (740) connected to the water outlet chamber (720); the top of the water inlet chamber (710) is connected to the cooling chamber (750); a water outlet hole (760) is provided in the cooling chamber (750), and the water outlet hole (760) is connected to the water outlet chamber (720).

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