Uniform-temperature sample stage for synthesizing diamond by CVD (Chemical Vapor Deposition) method

Abstract

The utility model discloses a sample table beneficial to uniform-temperature diamond synthesis by a CVD (Chemical Vapor Deposition) method, and belongs to the field of diamond artificial synthesis. Comprising a sample table body, the upper surface and the lower surface of the sample table body are horizontal planes, a heat insulation groove is formed in the bottom of the sample table body and is of an annular structure, the middle of the bottom of the sample table body is connected with an inner ring of the heat insulation groove, and the edge of the bottom of the sample table body is connected with an outer ring of the heat insulation groove; and the depth of the heat insulation groove is gradually increased from the inner ring to the outer ring. Compared with the prior art, the inner ring of the heat insulation groove of the sample table is close to the center of the sample table body, the outer ring is close to the edge of the sample table body, the groove depth of the inner ring is lower than that of the outer ring, and the heat insulation effect of the outer ring is higher than that of the inner ring, so that the heat dissipation effect of the middle of the sample table body is better than that of the edge; the plasma balls from the middle to the edge of the growth base and the atmosphere density are gradually reduced, so that the heat effect of the whole growth base is more uniform, the seed crystal can be heated more uniformly, and the yield and quality of products are improved.

Description

Technical Field

[0001] The utility model belongs to the field of diamond synthesis, and particularly relates to a sample table for synthesizing diamond by a CVD method which is beneficial to temperature uniformity. Background Art

[0002] In the process of synthesizing diamond crystals by MPCVD process, a growth base made of high melting point metal materials such as molybdenum needs to be set in the middle of the microwave resonant cavity to carry the seed crystal. The bottom of the existing growth base is completely flat, and the heat dissipation effect of the growth base is the same. In the microwave resonant cavity, there is a gradient difference between the density distribution center of the plasma sphere and the atmosphere from the edge to the edge, which will gradually weaken. Therefore, the thermal effect in the middle of the growth base is good, and the thermal effect at the edge is poor, which leads to uneven heating at the center and edge of the growth base, forming a heat transfer difference. The seed crystal at the edge of the growth base is more likely to have defects such as inclusions, microcracks, and uneven crystal color, thus affecting the output yield and crystal quality. Utility Model Content

[0003] In order to solve the above problems, the purpose of the utility model is to provide a sample stage for synthesizing diamond by CVD method which is conducive to temperature uniformity, so that the seed crystal can be heated more evenly and the yield and quality of the product can be improved.

[0004] To achieve the above purpose, the technical solution of the utility model is as follows:

[0005] The utility model provides a sample stage for synthesizing diamond by a CVD method which is conducive to uniform temperature, comprising: a sample stage body, the upper surface and the lower surface of the sample stage body are both horizontal planes, a heat insulation groove is arranged at the bottom of the sample stage body, the heat insulation groove is an annular structure, the middle part of the bottom of the sample stage body is connected to the inner ring of the heat insulation groove, the edge of the bottom of the sample stage body is connected to the outer ring of the heat insulation groove, and the depth of the heat insulation groove gradually increases from the inner ring to the outer ring.

[0006] In the present application, the inner ring of the annular thermal insulation groove is close to the center of the sample stage body, and the outer ring is close to the edge of the sample stage body. The groove depth of the inner ring is lower than that of the outer ring, and the thermal insulation effect of the outer ring is higher than that of the inner ring, so that the heat dissipation effect of the middle part of the sample stage body is better than that of the edge. Combined with the gradual decrease in the density of the plasma ball and atmosphere from the middle to the edge of the growth base, the thermal effect of the entire growth base is more uniform, which can make the seed crystal heated more evenly, thereby improving the yield and quality of the product.

[0007] Further, a horizontal circular surface is provided in the middle of the bottom of the sample stage body, and the horizontal circular surface is flush with the lower surface of the sample stage body. The bottom of the thermal insulation groove is an open structure. The bottom wall of the sample stage body in contact with the thermal insulation groove includes a first annular inclined surface, a second annular inclined surface, and an annular vertical surface; the inner ring of the first annular inclined surface is connected to the edge of the horizontal circular surface, and the outer ring is connected to the inner ring of the second annular inclined surface; the outer ring of the second annular inclined surface is connected to the upper edge of the annular vertical surface, and the lower edge of the annular vertical surface is connected to the lower surface of the sample stage body. In the present application, the horizontal circular surface is flush with the lower surface of the sample stage body, so that when the sample stage is placed on the base in the microwave resonant cavity, the horizontal circular surface is in direct contact with the base, and there is no thermal insulation groove in the middle to block it. The heat dissipation effect of the middle part of the sample stage body is much better than that of its edge. Combined with the higher density of plasma spheres and atmosphere in the middle part of the sample stage, the thermal effect of the middle part of the sample stage can be balanced, so that the seed crystals in the middle part and on the edge of the sample stage are heated more evenly.

[0008] Furthermore, the sample stage body is a cylindrical structure, and the diameter of the cylinder of the sample stage body includes but is not limited to 60 mm, the circle of the horizontal circular surface is located on the center line of the cylinder, and the diameter of the horizontal circular surface is 35%-40% of the diameter of the cylinder; the ratio of the width of the circular surface of the first annular slope projected on the horizontal plane to the diameter of the horizontal circular surface is 2:3, and the slope of the first annular slope is 4-6 degrees; from the cross-sectional view, a wedge-shaped thermal insulation groove can be formed, so that the heat dissipation effect is regularly weakened from the center to the edge, and the heating differences of the crystals in the middle and edge of the sample stage offset each other, so that the heating effect of the crystals is more uniform, and the growth effect of the crystals (growth temperature, growth rate, growth morphology, etc.) is more uniform, reducing the influence of the edge hillock on the color and quality of the crystals.

[0009] Furthermore, the edge thickness of the bottom of the sample stage body is 1.5-4 mm, so as to ensure the mechanical strength of the edge.

[0010] Compared with the prior art, the beneficial effects of the utility model are as follows: the sample stage is provided with an annular heat-insulating groove at the bottom, the inner ring of the annular heat-insulating groove is close to the center of the sample stage body, the outer ring is close to the edge of the sample stage body, the groove depth of the inner ring is lower than that of the outer ring, and the heat-insulating effect of the outer ring is higher than that of the inner ring, so that the heat dissipation effect of the middle part of the sample stage body is better than that of the edge, and the density of the plasma ball and atmosphere gradually decreases from the middle to the edge of the growth base, so that the thermal effect of the entire growth base is more uniform, the seed crystal can be heated more evenly, and the yield and quality of the product are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 1 is an isometric view of the sample stage of this embodiment.

[0012] Figure 2 It is the main view of the water axonometric drawing.

[0013] Figure 3 yes Figure 2 Cross-section view at AA in the middle.

[0014] Figure 4 This is a microscopic magnified image of crystal growth when a cylindrical sample stage with a diameter of 60 mm and completely flat upper and lower surfaces is used.

[0015] Figure 5 This is a microscopic magnified image of crystal growth when the sample stage of this embodiment is used. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0017] To achieve the above purpose, the technical solution of the utility model is as follows:

[0018] See also Figure 1-3 As shown, this embodiment provides a sample stage for CVD synthetic diamond that is conducive to uniform temperature, including: a sample stage body 1, the upper surface 2 and the lower surface 3 of the sample stage body 1 are both horizontal planes, and a heat insulation groove 4 is arranged at the bottom of the sample stage body 1. The heat insulation groove 4 is a ring structure, the middle part of the bottom of the sample stage body 1 is connected to the inner ring of the heat insulation groove 4, the edge of the bottom of the sample stage body 1 is connected to the outer ring of the heat insulation groove 4, and the depth of the heat insulation groove 4 gradually increases from the inner ring to the outer ring.

[0019] In this embodiment, the inner ring of the annular thermal insulation groove 4 is close to the center of the sample stage body 1, and the outer ring is close to the edge of the sample stage body 1. The groove depth of the inner ring is lower than that of the outer ring, and the thermal insulation effect of the outer ring is higher than that of the inner ring, so that the heat dissipation effect of the middle part of the sample stage body 1 is better than that of the edge. Combined with the gradual decrease in the density of the plasma ball and atmosphere from the middle to the edge of the growth base, the thermal effect of the entire growth base is more uniform, which can make the seed crystal heated more evenly, thereby improving the yield and quality of the product.

[0020] Furthermore, a horizontal circular surface 5 is provided in the middle of the bottom of the sample stage body 1, and the horizontal circular surface 5 is flush with the lower surface 3 of the sample stage body 1. The bottom of the thermal insulation groove 4 is an open structure, and the bottom wall of the bottom of the sample stage body 1 in contact with the thermal insulation groove 4 includes a first annular inclined surface 6, a second annular inclined surface 7, and an annular vertical surface 8; the inner ring of the first annular inclined surface 6 is connected to the edge of the horizontal circular surface 5, and the outer ring is connected to the inner ring of the second annular inclined surface 7; the outer ring of the second annular inclined surface 7 is connected to the upper edge of the annular vertical surface 8, and the lower edge of the annular vertical surface 8 is connected to the lower surface 3 of the sample stage body 1. In this embodiment, the horizontal circular surface 5 is flush with the lower surface 3 of the sample stage body 1, so that when the sample stage is placed on the base in the microwave resonant cavity, the horizontal circular surface 5 is in direct contact with the base without any insulation groove 4 in between. The heat dissipation effect of the middle part of the sample stage body 1 is much better than that of its edge. Combined with the higher density of plasma sphere and atmosphere in the middle part of the sample stage, the thermal effect of the middle part of the sample stage can be balanced, so that the seed crystals in the middle and on the edge of the sample stage are heated more evenly.

[0021] Furthermore, the sample stage body 1 is a cylindrical structure, and the diameter of the cylinder of the sample stage body 1 is 60 mm, the circle of the horizontal circular surface 5 is located on the center line of the cylinder, and the diameter of the horizontal circular surface 5 is 37.5% of the diameter of the cylinder; the ratio of the width of the circular surface of the first annular slope 6 projected on the horizontal plane to the diameter of the horizontal circular surface 5 is 2:3, and the slope of the first annular slope 6 is 4 degrees; from the cross-sectional view, a wedge-shaped insulation groove 4 can be formed, so that the heat dissipation effect is regularly weakened from the center to the edge, and the heating differences of the crystals in the middle and edge of the sample stage offset each other, so that the heating effect of the crystals is more uniform, and the growth effect of the crystals (growth temperature, growth rate, growth morphology, etc.) is more uniform, reducing the influence of the edge hillock on the color and quality of the crystals.

[0022] Furthermore, the edge thickness of the bottom of the sample stage body 1 is 3 mm, so as to ensure the mechanical strength of the edge.

[0023] Compared with the prior art, the beneficial effects of this embodiment are as follows: the sample stage is provided with an annular heat-insulating groove 4 at the bottom, the inner ring of the annular heat-insulating groove 4 is close to the center of the sample stage body 1, and the outer ring is close to the edge of the sample stage body 1, the groove depth of the inner ring is lower than that of the outer ring, and the heat-insulating effect of the outer ring is higher than that of the inner ring, so that the heat dissipation effect of the middle part of the sample stage body 1 is better than that of the edge, and the density of the plasma ball and atmosphere gradually decreases from the middle to the edge of the growth base, so that the thermal effect of the entire growth base is more uniform, the seed crystal can be heated more evenly, and the yield and quality of the product are improved.

[0024] See also Figure 4-5Compared with a cylindrical sample stage with a diameter of 60 mm and completely flat upper and lower surfaces, the sample stage of this embodiment can significantly improve the crystal uniformity under the same conditions of growth process, growth equipment, base material, growth time, etc., from the original uniformity of 30% to 65%, making the single crystal more transparent, reducing the introduction of edge hill-like crystals, and improving the color uniformity of the single crystal.

[0025] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A sample stage for CVD synthetic diamond that is conducive to uniform temperature, characterized in that: include: The sample stage body has an upper surface and a lower surface which are both horizontal planes, a heat insulation groove is arranged at the bottom of the sample stage body, and the heat insulation groove is a ring-shaped structure, the middle part of the bottom of the sample stage body is connected to the inner ring of the heat insulation groove, the edge of the bottom of the sample stage body is connected to the outer ring of the heat insulation groove, and the depth of the heat insulation groove gradually increases from the inner ring to the outer ring.

2. A sample stage for synthesizing diamond by CVD method which is beneficial to temperature uniformity as claimed in claim 1, characterized in that: A horizontal circular surface is provided in the middle of the bottom of the sample stage body, and the horizontal circular surface is flush with the lower surface of the sample stage body. The bottom of the thermal insulation groove is an open structure, and the bottom wall of the bottom of the sample stage body in contact with the thermal insulation groove includes a first annular inclined surface, a second annular inclined surface, and an annular vertical surface; the inner ring of the first annular inclined surface is connected to the edge of the horizontal circular surface, and the outer ring is connected to the inner ring of the second annular inclined surface; the outer ring of the second annular inclined surface is connected to the upper edge of the annular vertical surface, and the lower edge of the annular vertical surface is connected to the lower surface of the sample stage body.

3. A sample stage for synthesizing diamond by CVD method which is beneficial to temperature uniformity as claimed in claim 2, characterized in that: The sample stage body is a cylindrical structure, and the diameter of the cylinder of the sample stage body includes but is not limited to 60 mm. The circle of the horizontal circular surface is located on the center line of the cylinder, and the diameter of the horizontal circular surface is 35%-40% of the diameter of the cylinder; the ratio of the width of the first annular surface projected on the horizontal plane to the diameter of the horizontal circular surface is 2:3, and the slope of the first annular surface is 4-6 degrees.

4. A sample stage for synthesizing diamond by CVD method which is beneficial to temperature uniformity as claimed in claim 3, characterized in that: The edge thickness of the bottom of the sample stage body is 1.5-4 mm.

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