A method of growing a faceted diamond

Abstract

The present application belongs to the technical field of material science, and particularly relates to a molybdenum table for growing convex diamonds and a growing method. On one hand, the molybdenum table for growing convex diamonds comprises a bowl-shaped shell, at least four layers of annular rings, and a groove arranged at the bottom of the inner side of the bowl-shaped shell. On the other hand, the growing method for growing convex diamonds comprises the following steps: placing a substrate material into the groove of the molybdenum table; placing the molybdenum table with the substrate material into a microwave plasma chemical vapor deposition device; and processing the substrate material by using the microwave plasma chemical vapor deposition device to obtain a curved diamond. Compared with directly reducing the power to reduce the plasma area, the slant convex molybdenum ring group is used to control the size of the actual plasma area, so that the low-speed growth of the edge can be ensured, while directly reducing the power may lead to the edge position being unable to be covered by the plasma and thus unable to be effectively grown.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material science, and particularly relates to a molybdenum table for growing convex diamond and a growing method. BACKGROUND

[0002] With the increasingly wide application of diamond in the optical field, the market demand for convex diamond with specific curvature is increasing, and the flat diamond has gradually failed to meet the market demand of optical application. At present, the mainstream method for preparing convex diamond is to grow flat diamond and then process it, that is, to process the flat diamond into convex diamond with specific curvature by mechanical turning or laser processing, etc. This method usually needs to consume a large amount of processing time, and when the size of the diamond is larger or the curvature is larger, the processing time consumed is multiplied. In addition, the longer the processing time, the higher the probability of cracking in the processing process. SUMMARY

[0003] The present application aims to overcome the above-mentioned deficiencies in the prior art and provide a molybdenum table for growing convex diamond and a growing method.

[0004] In one aspect, to achieve the above-mentioned application purposes, the present application provides a molybdenum table for growing convex diamond, comprising:

[0005] a bowl-shaped shell;

[0006] at least four layers of circular rings, at least four layers of circular rings are vertically arranged from top to bottom inside the bowl-shaped shell, each layer of circular ring has a top opening and a bottom opening after vertical arrangement, the diameter of the top opening is larger than the diameter of the bottom opening, and the diameter of the bottom opening of the upper layer of circular ring is larger than the diameter of the top opening of the lower layer of circular ring, the center of the top opening of each layer of circular ring is located on the first vertical line, and the center of the bottom opening of each layer of circular ring is also located on the first vertical line; and

[0007] a groove, the groove is arranged at the bottom of the inside of the bowl-shaped shell.

[0008] In one embodiment, the diameter of the groove is 51 mm, and the depth of the groove is 0.5-2 mm.

[0009] In one embodiment, the vertical distance between the bottom opening of the upper layer of circular ring and the top opening of the lower layer of circular ring in the adjacent two layers of circular rings is the same.

[0010] In one embodiment, a first layer of circular ring, a second layer of circular ring, a third layer of circular ring and a fourth layer of circular ring are vertically arranged from top to bottom inside the bowl-shaped shell, and the diameters of the bottom openings of the first layer of circular ring, the second layer of circular ring, the third layer of circular ring and the fourth layer of circular ring are 60 mm, 57 mm, 54 mm and 51 mm, respectively.

[0011] In one embodiment, the material of the molybdenum table is molybdenum.

[0012] In another aspect, to achieve the above-mentioned object of the application, a growth method for growing a convex diamond is provided, which utilizes the above-mentioned molybdenum table to grow a convex diamond, and the growth method for growing a convex diamond comprises:

[0013] putting a substrate material into the groove of the molybdenum table;

[0014] putting the molybdenum table with the substrate material into the center of a substrate table of a microwave plasma chemical vapor deposition device, and using the microwave plasma chemical vapor deposition device to deposit diamond on the surface of the substrate material to obtain a curved diamond.

[0015] In one embodiment, the substrate material is Mo or Si.

[0016] In one embodiment, putting the molybdenum table with the substrate material into the center of a substrate table of a microwave plasma chemical vapor deposition device, and using the microwave plasma chemical vapor deposition device to deposit diamond on the surface of the substrate material to obtain a curved diamond, comprises:

[0017] In the microwave plasma chemical vapor deposition device, hydrogen and methane are introduced as process gas, the ratio of hydrogen and methane is 100:8, after ignition and excitation of plasma, the power is increased to 5900W, the gas pressure is 160torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the first layer of molybdenum ring, the emission spectrum of the plasma at different positions is collected, the change of C2 group in the plasma is monitored, at this time the center C2 group intensity is 85000, the outermost edge C2 group intensity is 82000; after growing for 25h, the microwave power is reduced to 5500W, the gas pressure is increased to 170torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the second layer of molybdenum ring, the change of C2 group is detected, the center C2 group intensity is 84000, the outermost edge C2 group intensity is 78000; after growing for 25h again, the microwave power is reduced to 5000W, the gas pressure is increased to 180torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the third layer of molybdenum ring, the change of C2 group is detected, the center C2 group intensity is 82000, the outermost edge C2 group intensity is 70000; after growing for 25h again, the microwave power is reduced to 4600W, the gas pressure is increased to 190torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the fourth layer of molybdenum ring, the change of C2 group is detected, the center C2 group intensity is 80000, the outermost edge C2 group intensity is 65000, after growing for 25h, the temperature is reduced to take out the diamond sample, after etching the substrate material with strong acid, the curved surface diamond is obtained.

[0018] In one embodiment, the thickness of the center of the curved surface diamond is about 500um, the deposition rate is about 5um / h, the thickness of the edge is about 300um, the deposition rate is about 3um / h, and the radius of curvature is about 1.625m.

[0019] The advantages and beneficial effects of the present application relative to the prior art are:

[0020] 1. Compared with directly processing a planar diamond, using a convex diamond to process a convex diamond with a specific curvature is more efficient and takes less time.

[0021] 2. Compared with directly reducing the power to reduce the plasma area, using the inclined convex molybdenum ring group to control the actual plasma area size can ensure the low-speed growth of the edge, while directly reducing the power may cause the edge position to be unable to cover the plasma and thus unable to effectively grow.

[0022] 3. In order to reduce the processing time of the diamond, the optimal method is to form a convex surface with a specific curvature during the growth of the diamond, and after the convex surface is formed, only slight shaping or surface roughness improvement is performed through mechanical processing, which takes much less time than processing a flat diamond into a convex diamond with a specific curvature, thereby improving the production efficiency of the curved diamond. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0024] Figure 1 A cross-sectional structure diagram of the molybdenum table described in the embodiments of the present application.

[0025] The marks in the figure are: 1, bowl-shaped shell; 2, first layer of annular ring; 3, second layer of annular ring; 4, third layer of annular ring; 5, fourth layer of annular ring; 6, groove. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects of the present application more clear, the present application will be further described in detail below in combination with the embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not used to limit the present application.

[0027] On the one hand, the present application provides a molybdenum table for growing convex diamond, comprising:

[0028] a bowl-shaped shell 1;

[0029] at least four layers of annular rings, at least four layers of annular rings are vertically arranged from top to bottom inside the bowl-shaped shell 1, each layer of annular ring has a top opening and a bottom opening after vertical arrangement, the diameter of the top opening is larger than the diameter of the bottom opening, and the diameter of the bottom opening of the upper layer of annular ring is larger than the diameter of the top opening of the lower layer of annular ring, the center of the top opening of each layer of annular ring is located on the first vertical line, and the center of the bottom opening of each layer of annular ring is also located on the first vertical line; and

[0030] a groove 6, the groove 6 is arranged at the bottom of the inside of the bowl-shaped shell 1.

[0031] The molybdenum table in the application can be used in a 2450MHz microwave plasma chemical vapor deposition device (the maximum diameter of the plasma ball is 3 inches, and the effective deposition area is about 60mm in diameter), and can also be used in a 915MHz microwave plasma chemical vapor deposition device (the maximum diameter of the plasma ball is 6 inches, and the effective deposition area is about 4-5 inches).

[0032] Further, the diameter of the groove 6 is 51mm, and the depth of the groove 6 is 0.5-2mm. For example, the depth can be 0.5mm, 1mm, 1.5mm, 2mm, etc.

[0033] Further, in the two adjacent layers of annular rings, the vertical distance between the bottom opening of the annular ring in the upper layer and the top opening of the annular ring in the lower layer is the same.

[0034] Further, the first layer of annular rings 2, the second layer of annular rings 3, the third layer of annular rings 4 and the fourth layer of annular rings 5 are vertically arranged in the bowl-shaped shell 1 from top to bottom, and the diameters of the bottom openings of the first layer of annular rings 2, the second layer of annular rings 3, the third layer of annular rings 4 and the fourth layer of annular rings 5 are 60mm, 57mm, 54mm and 51mm respectively.

[0035] Further, the material of the molybdenum table is molybdenum.

[0036] In one aspect, the application provides a molybdenum table for growing convex diamond, using the above-mentioned molybdenum table for growing convex diamond, the method for growing convex diamond comprises:

[0037] Put the substrate material into the groove 6 of the molybdenum table;

[0038] Put the molybdenum table with the substrate material into the center of the substrate table of the microwave plasma chemical vapor deposition device, and use the microwave plasma chemical vapor deposition device to deposit diamond on the surface of the substrate material to obtain curved diamond.

[0039] Since the size of the plasma in the microwave plasma chemical vapor deposition device is related to the microwave power and the reaction gas pressure, and when there is a convex object in the cavity, the electric field will form a cluster around the convex object and form a glow discharge, at this time the energy of the plasma field in this area will be concentrated, and then the plasma will remain the same size as the molybdenum ring.

[0040] Due to the glow discharge effect, the outer diameter of the plasma will tend to be consistent with the annular ring, and the application also uses this principle to obtain different stable sizes of plasma, and then obtain curved diamond with a certain curvature.

[0041] Further, the substrate material is Mo or Si. Metal Mo is often used as a substrate for preparing diamond because of its high thermal conductivity, high melting point and good thermal uniformity. Si can effectively improve the quality of diamond epitaxy as a substrate because its lattice constant and atomic arrangement are very similar to that of diamond structure. Therefore, the two kinds of substrate materials are often used for large-size diamond growth in the industry.

[0042] Further, the molybdenum table into which the substrate material is placed is placed in the middle of the substrate table of the microwave plasma chemical vapor deposition equipment, and diamond deposition is performed on the surface of the substrate material by using the microwave plasma chemical vapor deposition equipment to obtain a curved surface diamond, comprising:

[0043] Hydrogen and methane are introduced into the microwave plasma chemical vapor deposition equipment as process gases, the ratio of hydrogen to methane is 100:8, the power is increased to 5900W after ignition and excitation of plasma, the gas pressure is 160torr, and the temperature of the substrate material is maintained at 820-950℃. At this time, the plasma edge glows at the first layer of molybdenum ring, the emission spectrum of the plasma at different positions is collected, the change of C2 group in the plasma is monitored, the intensity of C2 group at the center is 85000, and the intensity of C2 group at the outermost edge is 82000; after growing for 25h, the microwave power is reduced to 5500W, the gas pressure is increased to 170torr, and the temperature of the substrate material is maintained at 820-950℃. At this time, the plasma edge glows at the second layer of molybdenum ring, the change of C2 group is detected, the intensity of C2 group at the center is 84000, and the intensity of C2 group at the outermost edge is 78000; after growing for 25h again, the microwave power is reduced to 5000W, the gas pressure is increased to 180torr, and the temperature of the substrate material is maintained at 820-950℃. At this time, the plasma edge glows at the third layer of molybdenum ring, the change of C2 group is detected, the intensity of C2 group at the center is 82000, and the intensity of C2 group at the outermost edge is 70000; after growing for 25h again, the microwave power is reduced to 4600W, the gas pressure is increased to 190torr, and the temperature of the substrate material is maintained at 820-950℃. At this time, the plasma edge glows at the fourth layer of molybdenum ring, the change of C2 group is detected, the intensity of C2 group at the center is 80000, and the intensity of C2 group at the outermost edge is 65000. After growing for 25h, the temperature is lowered to take out the diamond sample, and the substrate material is etched away by strong acid to obtain the curved surface diamond.

[0044] OES refers to that atoms or molecules absorb external energy to generate excited atoms or ions, the excited atoms or ions transition from high energy level to low energy level, and the excess energy is released in the form of photons, thereby generating characteristic spectrum. In a microwave plasma chemical vapor deposition (MPCVD) device, plasma electrons are affected by a microwave electric field, and emit specific frequency spectrum outward, which can represent the energy state of the plasma electrons and changes with the change of the electric field. In the plasma composed of H2 and CH4, CH and C2 groups are important precursors for diamond deposition, and the energy size will directly affect the deposition rate of diamond, and the energy size of C2 group is used as a reference for measuring the growth rate of diamond in the application. The measurement positions of the plasma spectrum are above the center of the substrate and the outermost circle of the substrate respectively. The plasma emission spectrum is an in-situ detection method for detecting electron groups in the plasma, which can detect the relative concentration of specific groups in the plasma, and further detect the concentration change of groups at different positions.

[0045] When convex diamond growth is carried out using the molybdenum platform, first, high microwave power and low reaction gas pressure are used, at this time, the plasma edge glows at the first layer of molybdenum ring; when the diamond grows to a certain thickness, the microwave power is reduced, the reaction gas pressure is increased, and the growth temperature is kept unchanged, at this time, the plasma edge glows at the second layer of molybdenum ring; after growing to a certain thickness, the microwave power is reduced again, the reaction gas pressure is increased, and the growth temperature is kept unchanged, the plasma edge glows at the third layer of molybdenum ring; after growing to a certain thickness, the microwave power is reduced again, the reaction gas pressure is increased, and the growth temperature is kept unchanged, the plasma edge glows at the fourth layer of molybdenum ring;

[0046] The size of the plasma is positively correlated with the microwave power, and under normal circumstances, the size of the plasma will also continuously decrease with the continuous reduction of the microwave power, but the existence of the circular ring makes the size of the plasma decrease in a stepwise manner; when the microwave power is reduced each time and the size of the plasma is reduced, the number and energy of carbon groups at the periphery of the plasma will be reduced, thereby reducing the deposition rate in this region, and the final result is that the diamond growth rate in the central region is higher than that in the edge region, thereby forming a convex diamond.

[0047] The application can also adjust the time for which the plasma maintains a corresponding size at the corresponding molybdenum ring according to specific curvature requirements, thereby obtaining different curvatures.

[0048] Further, the thickness of the center of the curved diamond is about 500um, the deposition rate is about 5um / h, the thickness of the edge is about 300um, the deposition rate is about 3um / h, and the curvature radius is about 1.625m.

[0049] The present application has undergone multiple tests, now a part of the test results as a reference to further describe the invention in detail, the following specific examples are described in detail.

[0050] Example 1

[0051] A molybdenum table for growing convex diamonds, comprising: a bowl-shaped shell 1; at least four layers of annular rings, a first layer of annular rings 2, a second layer of annular rings 3, a third layer of annular rings 4 and a fourth layer of annular rings 5 are vertically arranged from top to bottom inside the bowl-shaped shell 1, each layer of annular rings has a top opening and a bottom opening after vertical arrangement, the diameter of the top opening is larger than the diameter of the bottom opening, and the diameter of the bottom opening of the upper layer of annular rings is larger than the diameter of the top opening of the lower layer of annular rings, the center of the top opening of each layer of annular rings is located on the first vertical line, and the center of the bottom opening of each layer of annular rings is also located on the first vertical line; the diameters of the bottom openings of the first layer of annular rings 2, the second layer of annular rings 3, the third layer of annular rings 4 and the fourth layer of annular rings 5 are 60mm, 57mm, 54mm and 51mm respectively; in adjacent two layers of annular rings, the vertical distance between the bottom opening of the upper layer of annular rings and the top opening of the lower layer of annular rings is the same; and a groove 6 is arranged at the bottom of the inside of the bowl-shaped shell 1, the diameter of the groove 6 is 51mm, and the depth of the groove 6 is 2mm; the material of the whole molybdenum table is molybdenum.

[0052] Example 2

[0053] A growth method for growing convex diamonds, using the molybdenum table described in example 1 to grow convex diamonds, the growth method for growing convex diamonds comprises:

[0054] Put the substrate material Mo into the groove 6 of the molybdenum table;

[0055] In the microwave plasma chemical vapor deposition device, hydrogen and methane are introduced as process gas, the ratio of hydrogen and methane is 100:8, after ignition and excitation of plasma, the power is increased to 5900W, the gas pressure is 160torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the first layer of molybdenum ring, the emission spectrum of the plasma at different positions is collected, the change of C2 group in the plasma is monitored, at this time the center C2 group intensity is 85000, the outermost edge C2 group intensity is 82000; after growing for 25h, the microwave power is reduced to 5500W, the gas pressure is increased to 170torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the second layer of molybdenum ring, the change of C2 group is detected, the center C2 group intensity is 84000, the outermost edge C2 group intensity is 78000; after growing for 25h again, the microwave power is reduced to 5000W, the gas pressure is increased to 180torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the third layer of molybdenum ring, the change of C2 group is detected, the center C2 group intensity is 82000, the outermost edge C2 group intensity is 70000; after growing for 25h again, the microwave power is reduced to 4600W, the gas pressure is increased to 190torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the fourth layer of molybdenum ring, the change of C2 group is detected, the center C2 group intensity is 80000, the outermost edge C2 group intensity is 65000, after growing for 25h, the temperature is reduced to take out the diamond sample, after etching the substrate material with strong acid, the curved surface diamond is obtained.

[0056] The thickness of the center of the curved surface diamond is about 500um, the deposition rate is about 5um / h, the thickness of the edge is about 300um, the deposition rate is about 3um / h, and the radius of curvature is about 1.625m.

[0057] The first layer of molybdenum ring, the second layer of molybdenum ring, the third layer of molybdenum ring and the fourth layer of molybdenum ring in the embodiment correspond to the first layer of circular ring 2, the second layer of circular ring 3, the third layer of circular ring 4 and the fourth layer of circular ring 5 respectively.

[0058] Example 3

[0059] A growth method for growing convex diamond, using the molybdenum table described in example 1 to grow convex diamond, the growth method for growing convex diamond comprises:

[0060] The substrate material Si is placed in the groove 6 of the molybdenum table;

[0061] In the microwave plasma chemical vapor deposition device, hydrogen and methane are introduced as process gas, the ratio of hydrogen and methane is 100:8, after ignition excitation plasma, the power is increased to 5900W, the gas pressure is 160torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the first layer of molybdenum ring, the emission spectrum of different positions of the plasma is collected, the change of C2 group in the plasma is monitored, at this time the center C2 group intensity is 85000, the outermost edge C2 group intensity is 82000; after growing for 25h, the microwave power is reduced to 5500W, the gas pressure is increased to 170torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the second layer of molybdenum ring, the change of C2 group is detected, the center C2 group intensity is 84000, the outermost edge C2 group intensity is 78000; after growing for 25h again, the microwave power is reduced to 5000W, the gas pressure is increased to 180torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the third layer of molybdenum ring, the change of C2 group is detected, the center C2 group intensity is 82000, the outermost edge C2 group intensity is 70000; after growing for 25h again, the microwave power is reduced to 4600W, the gas pressure is increased to 190torr, the temperature of the substrate material is maintained at 820-950℃, at this time the plasma edge glows at the fourth layer of molybdenum ring, the change of C2 group is detected, the center C2 group intensity is 80000, the outermost edge C2 group intensity is 65000, after growing for 25h, the temperature is reduced to take out the diamond sample, after etching the substrate material with strong acid, the curved surface diamond is obtained.

[0062] The thickness of the center of the prepared curved surface diamond is about 500um, the deposition rate is about 5um / h, the thickness of the edge is about 300um, the deposition rate is about 3um / h, and the curvature radius is about 1.625m.

[0063] The first layer of molybdenum ring, the second layer of molybdenum ring, the third layer of molybdenum ring and the fourth layer of molybdenum ring in the embodiment correspond to the first layer of circular ring 2, the second layer of circular ring 3, the third layer of circular ring 4 and the fourth layer of circular ring 5 respectively.

[0064] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for growing convex diamond, characterized in that, A molybdenum stage is used for the growth of convex diamond, wherein the molybdenum stage comprises: Bowl-shaped shell; At least four rings are vertically arranged from top to bottom inside the bowl-shaped shell. Each ring has a top opening and a bottom opening. The diameter of the top opening is larger than the diameter of the bottom opening, and the diameter of the bottom opening of the previous ring is larger than the diameter of the top opening of the next ring. The center of the top opening of each ring is located on a first vertical line, and the center of the bottom opening of each ring is also located on the first vertical line. A groove, wherein the groove is disposed at the bottom of the inner side of the bowl-shaped shell; The method for growing convex diamond includes: The substrate material is placed into the groove of the molybdenum stage; A molybdenum stage containing the substrate material is placed in the center of the substrate stage of a microwave plasma chemical vapor deposition (MPCVD) device, and diamond is deposited on the surface of the substrate material using the MCVD device to obtain curved diamond. A molybdenum stage containing the substrate material is placed in the center of the substrate stage of a microwave plasma chemical vapor deposition (MPCVD) apparatus. Diamond is deposited on the surface of the substrate material using the MPCVD apparatus to obtain curved diamond, including: In the microwave plasma chemical vapor deposition equipment, hydrogen and methane are introduced as process gases in a ratio of 100:

8. After ignition and plasma excitation, the power is increased to 5900W, the gas pressure is 160 torr, and the substrate material temperature is maintained at 820℃-950℃. At this time, glow discharge occurs at the edge of the plasma at the first molybdenum ring. The emission spectra at different positions of the plasma are collected to monitor the changes in C2 groups in the plasma. At this time, the intensity of the central C2 group is 85000, and the intensity of the outermost C2 group is 82000. After 25 hours of growth, the microwave power is reduced to 5500W, the gas pressure is increased to 170 torr, and the substrate material temperature is maintained at 820℃-950℃. At this time, glow discharge occurs at the edge of the plasma at the second molybdenum ring. The changes in C2 groups are detected. The intensity of the central C2 group is 84000, and the intensity of the outermost C2 group is 84000. The C2 group strength was 78000. After 25 hours of growth, the microwave power was reduced to 5000W, the gas pressure was increased to 180 torr, and the substrate temperature was maintained at 820℃-950℃. At this time, glow discharge occurred at the edge of the plasma at the third molybdenum ring, and the C2 group changes were detected. The C2 group strength at the center was 82000, and the C2 group strength at the outermost edge was 70000. After 25 hours of growth, the microwave power was reduced to 4600W, the gas pressure was increased to 190 torr, and the substrate temperature was maintained at 820℃-950℃. At this time, glow discharge occurred at the edge of the plasma at the fourth molybdenum ring, and the C2 group changes were detected. The C2 group strength at the center was 80000, and the C2 group strength at the outermost edge was 65000. After 25 hours of growth, the diamond sample was cooled and removed. The substrate material was etched away with strong acid to obtain the curved diamond.

2. The method for growing convex diamond according to claim 1, characterized in that, The diameter of the groove is 51 mm, and the depth of the groove is 0.5-2 mm.

3. The method for growing convex diamond according to claim 1, characterized in that, In two adjacent ring layers, the vertical distance between the bottom opening of the ring in the upper layer and the top opening of the ring in the lower layer is the same.

4. The method for growing convex diamond according to claim 1, characterized in that, A first ring, a second ring, a third ring, and a fourth ring are vertically arranged from top to bottom on the inner side of the bowl-shaped shell. The diameters of the bottom openings of the first ring, the second ring, the third ring, and the fourth ring are 60mm, 57mm, 54mm, and 51mm, respectively.

5. The method for growing convex diamond according to claim 1, characterized in that, The molybdenum platform is made of molybdenum.

6. The method for growing convex diamond according to claim 1, characterized in that, The substrate material is Mo or Si.

7. The method for growing convex diamond according to claim 1, characterized in that, The thickness of the curved diamond at the center is 500 μm with a deposition rate of 5 μm / h, the thickness at the edge is 300 μm with a deposition rate of 3 μm / h, and the radius of curvature is 1.625 m.

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