CN219059207U - Substrate table for single crystal diamond growth - Google Patents

Abstract

The utility model belongs to the field of preparation of single crystal diamond, and discloses a substrate table for growth of single crystal diamond. The substrate table comprises a substrate table main body with a cylindrical structure or a truncated cone-shaped structure, wherein a circular groove is formed in the upper surface of the substrate table main body, and a plurality of grid grooves for accommodating seed crystals are formed in the bottom of the circular groove; the width of the grid groove is 0.15-0.5 mm larger than that of the seed crystal, the depth of the grid groove is 0.05-0.15 mm smaller than the thickness of the seed crystal, and the width of a limit step between two grids is 0.9-1.5 mm; the diameter of the circular groove is 1-3 mm smaller than that of the upper surface of the substrate table, and the depth of the circular groove is 0.5-1 mm larger than the difference of the seed crystal thickness minus the depth of the grid groove. The substrate table has simple structure, is easy to produce and manufacture, can prepare high-quality and high-flatness monocrystal diamond in a large scale, reduces the production cost and has good industrial application prospect.

Description

Substrate table for single crystal diamond growth

Technical Field

The utility model belongs to the field of preparation of single crystal diamond, and particularly relates to a substrate table for growth of single crystal diamond.

Background

The microwave chemical vapor deposition (MPCVD) method has become the preferred solution for preparing high-quality diamond by virtue of its advantages of high plasma density and no electrode pollution. During deposition of MPCVD, the structure of the substrate table used has an impact on the deposition rate and preparation quality of diamond.

However, due to the "edge effect" of microwave discharge, the temperature of the seed crystal is gradually reduced from the edge to the center when diamond is deposited, the temperature difference can be even tens of degrees, and the "edge effect" of the diamond single crystal is enhanced along with the increase of the height difference between the growth surface of the diamond single crystal and the substrate table, so that the prepared diamond has extremely poor surface flatness. And the edge polycrystalline diamond gradually expands towards the inside of the seed crystal during growth, and finally the single crystal growth area is reduced. To obtain a larger single crystal, the growth must be stopped after a period of time so that the single growth thickness is smaller. Meanwhile, the heat dissipation of the seed crystal is different due to different contact conditions between the bottom of each seed crystal and the substrate table in the growth process, and sometimes the temperature difference of each seed crystal is larger, so that the quality of the prepared single crystal diamond is inconsistent.

Disclosure of Invention

In view of the foregoing problems in the prior art, an object of the present utility model is to provide a substrate table for growing single crystal diamond, which has a simple structure and low cost, and which can effectively mitigate edge effects during normal processes of single crystal diamond.

In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows:

the substrate table for growing the single crystal diamond comprises a substrate table main body with a cylindrical structure or a truncated cone-shaped structure, wherein a circular groove is formed in the upper surface of the substrate table main body, and a plurality of grid grooves for accommodating seed crystals are formed in the bottom of the circular groove;

the width of the grid groove is 0.15-0.5 mm larger than that of the seed crystal, the depth of the grid groove is 0.05-0.15 mm smaller than the thickness of the seed crystal, and the width of a limit step between two grids is (0.9-1.5) mm; the diameter of the circular groove is 1-3 mm smaller than that of the upper surface of the substrate table, and the depth of the circular groove is 0.5-1 mm larger than the difference of the seed crystal thickness minus the depth of the grid groove.

Preferably, the center of the circular groove coincides with the center of the surface of the substrate table main body.

Preferably, the seed crystal is of a square columnar structure, and the grid grooves are of a square columnar hollow structure.

Preferably, the grid grooves are uniformly formed on the upper surface of the substrate table main body; the grid grooves are arranged on the upper surface of the substrate table main body in any one of a plurality of linear array arrangements, a plurality of layers of circumferential array arrangements and a plurality of layers of rectangular array arrangements.

Preferably, the distance between adjacent grid grooves is 0.9-1.5 mm.

Preferably, adjacent grid grooves are communicated with each other. After a certain time of diamond growth is considered, polycrystalline diamond starts to grow on the substrate table, and adjacent grid grooves are communicated, so that the temperature difference of each point and the temperature difference of each seed crystal of the whole substrate table are reduced.

The square columnar structure mentioned in the present utility model is a rectangular structure with equal length and width.

Compared with the prior art, the utility model has the beneficial effects that:

(1) According to the utility model, the circular grooves are formed in the substrate table, and the grid grooves are formed in the circular grooves, so that the limit steps of the circular grooves leave enough growth space for the transverse growth of the diamond in the growth process of the single-crystal diamond. The surface of the seed crystal is lower than the edge of the substrate table before growth, the edge effect of the seed crystal is transferred to the edge of the substrate table, the temperature distribution on the seed crystal is greatly improved, the growth of polycrystalline diamond at the edge is restrained, the surface of the growth is promoted to be flat, and the thickness of single growth is increased.

(2) The substrate table has simple structure, is easy to produce and manufacture, can prepare high-quality and high-flatness monocrystal diamond in a large scale, reduces the production cost and has good industrial application prospect.

Drawings

The accompanying drawings are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate the utility model and together with the embodiments of the utility model, serve to explain the utility model. In the drawings:

FIG. 1 is a top view of a substrate table for single crystal diamond growth according to the present utility model;

FIG. 2 is a cross-sectional view of a substrate table for single crystal diamond growth according to the present utility model;

FIG. 3 is a partially enlarged block diagram of FIG. 2;

fig. 4 is a process flow diagram of the present utility model.

Detailed Description

The present utility model will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments are shown, for the purpose of illustrating the utility model, but the scope of the utility model is not limited to the specific embodiments shown.

Unless defined otherwise, all technical and scientific terms used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the scope of the present utility model.

Unless otherwise specifically indicated, the various raw materials, reagents, instruments, equipment and the like used in the present utility model are commercially available or may be prepared by existing methods.

Example 1

As shown in fig. 1 to 3, the embodiment provides a substrate table for growing single crystal diamond, the substrate table includes a substrate table main body 1 having a circular table structure, the substrate table main body 1 has a circular table structure with a top surface diameter of 53mm, wherein it is to be noted that the top surface and the side surface of the substrate table main body 1 are in arc transition, a circular groove 2 is provided on the upper surface of the substrate table main body 1, the diameter of the circular groove 2 is 52mm, and the depth of the circular groove 2 is 0.65mm.

The circular grooves 2 are internally and uniformly provided with 23 grid grooves 3 with square columnar hollow structures, the grid grooves are used for accommodating and limiting seed crystals and are arranged in a layered linear array, the length, width and height parameters of the seed crystals to be accommodated are 5mm multiplied by 0.3mm, the width of each grid groove 3 is 5.2mm, and the depth of each grid groove 3 is 0.15mm;

in this embodiment, the distance between adjacent mesh grooves 3 is 0.9mm. And the adjacent grid grooves 3 are communicated with each other, which is shown in the embodiment that the adjacent grid grooves 3 are communicated with each other at the connection vertex angle, so that the temperature difference of each point of the whole substrate table and the temperature difference of each seed crystal are further reduced.

Example 2

This embodiment is substantially identical to embodiment 1, except that: the depth of the circular grooves is 1.15mm, and the distance between the adjacent grid grooves is 1.5mm.

Example 3

The embodiment provides a method for preparing single crystal diamond, comprising the following steps:

(1) Seed crystals (5 mm multiplied by 0.3 mm) with the height close to each other are selected, and the height difference is less than or equal to 0.09mm. Observing the shape of the growth surface of the seed crystal in a microscope, and eliminating unqualified seed crystals. Ultrasonically cleaning qualified seed crystal with deionized water for 10min, and finally placing the seed crystal into aqua regia for pickling until no bubbles are generated on the surface of the seed crystal;

(2) Ultrasonically cleaning the substrate table in the embodiment 1 for 5-10 min, plating a carbon film with the thickness of 10 mu m on the upper surface of the substrate table main body, the surfaces of the circular grooves and the surfaces of the grid grooves, ultrasonically cleaning for 3-5 min after the plating is completed, and drying by using dry air;

(3) And (3) sequentially carrying out ultrasonic treatment on the seed crystal subjected to acid washing in the step (1) by deionized water, acetone and absolute ethyl alcohol for 10min, and drying by dry nitrogen. And (3) sequentially placing seed crystals into the grid grooves of the substrate table after the coating in the step (2) according to the number, and placing the substrate table into the deposition cavity after the placing is completed. Pumping the pressure of the cavity to be lower than 0.8Pa, opening a hydrogen valve, setting the hydrogen flow value to be 400sccm, starting microwaves after the pressure is raised to be 1kPa, setting the microwave power to be 600W, setting the heating speed to be 10 ℃/min, heating to be 900 ℃, setting the pressure rise value to be 17KPa, and etching for 30min;

(4) After etching, introducing methane, carbon dioxide, argon and nitrogen, setting a methane flow value of 32sccm, a carbon dioxide flow value of 2sccm, an argon flow value of 10sccm, a nitrogen flow value of 0.1sccm, setting a pressure of 20kPa, maintaining the temperature at 950 ℃, and growing for 180 hours;

(5) And after the growth is completed, stopping introducing methane, carbon dioxide, argon and nitrogen, setting the heating rate to 5 ℃/min, heating to 1300 ℃, preserving heat for 1h, then cooling at the temperature of 200 ℃ with the gradient of 2 ℃/min, preserving heat for 1h at each gradient temperature, and stopping introducing hydrogen to obtain the monocrystalline diamond by closing microwaves.

Example 4

This example is substantially identical to example 3, except that: the substrate table for single crystal diamond growth in example 2 was used.

Example 5

This example is substantially identical to example 3, except that: in the step (2), the thickness of the carbon film was 5. Mu.m, the flow rate of carbon dioxide was 0.5sccm, the flow rate of argon was 1sccm, and the flow rate of nitrogen was 0.05sccm.

Example 6

This example is substantially identical to example 3, except that: in the step (4), the pressure during the growth was 24kPa and the temperature was 1050 ℃.

Comparative example 1

This example is substantially identical to example 3, except that: in embodiments the substrate table does not have a circular recess.

Comparative example 2

This example is substantially identical to example 4, except that: the depth of the circular groove of the substrate table in the embodiment is 2mm.

Comparative example 3

This example is substantially identical to example 3, except that: and (3) removing the step (2).

Comparative example 4

This example is substantially identical to example 3, except that: in the step (4), the flow rate of carbon dioxide was 4sccm, the flow rate of argon was 10sccm, and the flow rate of nitrogen was 0.1sccm.

Comparative example 5

This example is substantially identical to example 3, except that: in the step (4), the flow rate of carbon dioxide was 2sccm, the flow rate of argon was 0.1sccm, and the flow rate of nitrogen was 0sccm.

Comparative example 6

This example is substantially identical to example 3, except that: in the step (4), the pressure during growth is 15kPa.

Comparative example 7

This example is substantially identical to example 3, except that: in the step (4), the growth temperature is 1100 ℃.

The growth process of the single crystal diamond of examples 3 to 6 and comparative examples 1 to 7 was examined, and the results are shown in table 1. It is apparent from the experimental data table that the thicker the carbon film, the smaller the temperature difference between the seeds. The larger the depth of the circular groove, the more smooth the growth surface will be and the more obvious the lateral growth will be, but the slower the growth rate, the temperature and pressure will have a certain effect on the lateral growth.

TABLE 1

The above is only a preferred embodiment of the present utility model, and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the scope of the present utility model.

Claims (6)

1. The substrate table for growing the single crystal diamond is characterized by comprising a substrate table main body with a cylindrical structure or a truncated cone-shaped structure, wherein a circular groove is formed in the upper surface of the substrate table main body, and a plurality of grid grooves for accommodating seed crystals are formed in the bottom of the circular groove;

the width of the grid groove is 0.15-0.5 mm larger than that of the seed crystal, the depth of the grid groove is 0.05-0.15 mm smaller than the thickness of the seed crystal, and the width of a limit step between two grids is 0.9-1.5 mm; the diameter of the circular groove is 1-3 mm smaller than that of the upper surface of the substrate table, and the depth of the circular groove is 0.5-1 mm larger than the difference of the seed crystal thickness minus the depth of the grid groove.

2. The substrate table of claim 1, wherein a center of the circular recess coincides with a center of a surface of the substrate table body.

3. The substrate table of claim 1, wherein the seed crystal is a square columnar structure and the grid grooves are square columnar hollow structures.

4. The substrate table according to claim 1, wherein the mesh grooves are uniformly provided on the upper surface of the substrate table main body; the grid grooves are arranged on the upper surface of the substrate table main body in any one of a plurality of linear array arrangements, a plurality of layers of circumferential array arrangements and a plurality of layers of rectangular array arrangements.

5. The substrate table of claim 1, wherein a distance between adjacent grid grooves is 0.9-1.5 mm.

6. The substrate table of any one of claims 1-5, wherein adjacent grid grooves are in communication with each other.

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