CN115726030A - Preparation method of single crystal diamond - Google Patents
Preparation method of single crystal diamond Download PDFInfo
- Publication number
- CN115726030A CN115726030A CN202211594172.7A CN202211594172A CN115726030A CN 115726030 A CN115726030 A CN 115726030A CN 202211594172 A CN202211594172 A CN 202211594172A CN 115726030 A CN115726030 A CN 115726030A
- Authority
- CN
- China
- Prior art keywords
- substrate table
- temperature
- growth
- seed crystal
- diamond
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The invention belongs to the field of diamond preparation, and discloses a preparation method of a single crystal diamond. The method comprises the following steps: selecting seed crystals with approximate heights, and carrying out acid washing treatment; preparing a substrate table, plating a carbon film on the upper surface of the substrate table, wherein the thickness of the carbon film is 5 to 10 mu m, and cleaning and drying after the film plating is finished; placing the seed crystal after acid washing into a coated substrate table, placing the substrate table into a deposition cavity, vacuumizing, introducing hydrogen, and starting microwave etching; after etching, introducing mixed gas of methane, carbon dioxide, argon and nitrogen for growth; and after the growth is finished, stopping introducing methane, increasing the temperature to 100-150 ℃ on the basis of the growth temperature, preserving the temperature, and then cooling to room temperature to obtain the monocrystalline diamond. The invention greatly improves the temperature distribution on the seed crystal, promotes the growth surface to be flat, and can prepare the high-quality and high-flatness monocrystal diamond in large batch.
Description
Technical Field
The invention belongs to the field of diamond preparation, and particularly relates to a preparation method of a single crystal diamond.
Background
The Microwave Plasma Chemical Vapor Deposition (MPCVD) is the preferred solution for preparing large-sized high-quality diamond by virtue of its advantages of high plasma density and no electrode pollution. In the deposition process of MPCVD, the structural characteristics of the substrate table used and the preparation method used have a significant impact on the deposition rate and preparation quality of diamond.
However, due to the "edge effect" of microwave discharge, when the diamond is deposited, the temperature of the seed crystal is gradually reduced from the edge to the center, and the temperature difference can even reach tens of degrees. And the polycrystalline diamond at the edge gradually expands towards the interior of the seed crystal during growth, and finally the growth area of the single crystal is reduced. To obtain a larger single crystal, growth must be stopped after a period of growth, so that the thickness of a single growth is small; at the same time. Because the contact condition of the bottom of each seed crystal and the substrate table is different in the growth process, the heat dissipation of the seed crystal is different, and the temperature difference of each seed crystal is larger sometimes, so that the quality of the prepared single crystal diamond is inconsistent.
Therefore, it is necessary to develop a substrate stage structure for single crystal diamond production and a method for producing single crystal diamond compatible with the structure.
Disclosure of Invention
Aiming at the problems in the prior art, the invention aims to provide a preparation method of a single crystal diamond, which promotes the lateral growth of seed crystals, namely the diameter expansion growth, in the early stage of growth, inhibits the growth of polycrystalline diamond at the edges of the seed crystals, enlarges the growth area of the single crystal diamond, greatly improves the temperature distribution on the seed crystals, and ensures that each seed crystal grows flat single crystal diamond and the single growth thickness is improved.
In order to realize the purpose of the invention, the specific technical scheme is as follows:
a method of producing a single crystal diamond, comprising the steps of:
(1) Selecting seed crystals with approximate heights, and carrying out acid washing treatment;
(2) Preparing a substrate table, plating a carbon film with the thickness of 5 to 10 mu m on the upper surface of the substrate table, and cleaning and drying after the film plating is finished;
(3) Putting the seed crystal after acid washing in the step (1) into the substrate table after film coating obtained in the step (2), putting the substrate table into a deposition cavity, vacuumizing, introducing hydrogen, starting microwaves, and etching for 0.5 to 2h at the temperature of 700 to 1000 ℃ and the pressure of 17 to 21kPa;
(4) After etching is finished, introducing methane, carbon dioxide, argon and nitrogen, and growing for 180 to 200h in an environment with the pressure of 20 to 25kPa and the temperature of 900 to 1050 ℃;
(5) And (3) after the growth is finished, stopping introducing methane, carbon dioxide, argon and nitrogen, increasing the growth temperature in the step (4) by 100 to 150 ℃, preserving the temperature for 1 to 2h, then cooling by taking the temperature of 100 to 200 ℃ as a gradient, preserving the temperature for 1 to 2h at each gradient temperature, cooling to room temperature, closing the microwave, and stopping introducing hydrogen to obtain the monocrystalline diamond.
Preferably, in the step (1), in the acid washing treatment, the acid solution is one or more of aqua regia and concentrated sulfuric acid; and pickling until no bubbles are generated on the surface of the seed crystal.
Preferably, in step (1), the seed crystals with close heights are specifically: the height difference between different seed crystals is less than or equal to 0.09mm.
Preferably, in the step (2), the substrate table comprises a substrate table main body of a cylindrical structure or a truncated cone structure, a circular groove is formed on the upper surface of the substrate table main body, and a plurality of grid grooves for accommodating seed crystals are formed at the bottom of the circular groove;
the width of the grid groove is 0.15 to 0.5mm larger than that of the seed crystal, the depth of the grid groove is 0.05 to 0.15mm smaller than that of the seed crystal, and the width of a limiting step between the two grids is 0.9 to 1.5mm; the diameter of the circular groove is 1 to 3mm smaller than the diameter of the upper surface of the substrate table, and the depth of the circular groove is 0.5 to 1mm larger than the difference between the thickness of the seed crystal and the depth of the grid groove;
the carbon film is arranged on the upper surface of the substrate table main body, the surface of the circular groove and the surface of the grid groove.
Further preferably, a center of the circular groove coincides with a center of the substrate table main body surface.
Further preferably, the seed crystal is of a square column structure, and the grid groove is of a square column hollow structure.
Further preferably, the grid 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 arrays, a plurality of layers of circumferential arrays and a plurality of layers of rectangular arrays.
Further preferably, the distance between the adjacent grid grooves is 0.9 to 1.5mm; the adjacent grid grooves are communicated with each other.
Preferably, in the steps (3) to (5), the flow rate of the introduced hydrogen is 400 to 500sccm; in the step (4), the flow rate of methane ranges from 8 to 75sccm, the flow rate of carbon dioxide ranges from 0.5 to 3sccm, the flow rate of argon ranges from 1 to 10sccm, and the flow rate of nitrogen ranges from 0.05 to 0.1sccm.
Preferably, in the steps (3) to (5), the heating rate is 5 to 20 ℃/min; in the step (5), the cooling rate is 1 to 2 ℃/min.
The square columnar (hollow) structure mentioned in the present invention is a rectangular parallelepiped (hollow) structure having the same length and width.
Compared with the prior art, the invention has the beneficial effects that:
(1) The preparation method of the invention ensures that the lateral growth trend of the diamond at the early stage of growth is very obvious, expands the growth area of the single crystal diamond, inhibits the growth of the polycrystalline diamond at the edge of the seed crystal and improves the thickness of single growth.
(2) The preparation method can prepare the monocrystalline diamond with high quality and high flatness in large batch, and the circular groove and the grid arranged on the upper surface of the used substrate table leave enough growth space for the transverse growth of the diamond. Before growth, the seed crystal surface is lower than the edge of the substrate table, 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 inhibited, and the leveling of the growth surface is promoted.
(3) According to the invention, the carbon film is creatively arranged on the substrate table, and due to the existence of the carbon film on the substrate table, the temperature difference of each seed crystal at the early stage is small, and the quality of the grown single crystal diamond is uniform.
(4) The substrate table disclosed by the invention is simple in structure, easy to produce and manufacture, capable of preparing high-quality and high-flatness single crystal diamonds in a large scale, and capable of reducing the production cost, and has a good industrial application prospect.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.
In the drawings:
FIG. 1 is a top view structural view of a substrate stage for growing a single crystal diamond according to the present invention;
FIG. 2 is a sectional view showing a structure of a substrate stage for growing a single crystal diamond according to the present invention;
FIG. 3 is a partially enlarged view of the structure of FIG. 2;
FIG. 4 is a process flow diagram of the present invention.
Detailed Description
In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.
Unless otherwise defined, all terms of art 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 limit the scope of the present invention.
Unless otherwise specifically indicated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
Example 1
As shown in fig. 1 to 3, in the present embodiment, a substrate table for single crystal diamond growth is provided, the substrate table includes a substrate table main body 1 having a truncated cone-shaped structure, the substrate table main body 1 has a truncated cone-shaped structure with a top surface diameter of 53mm, where 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.
23 grid grooves 3 with square cylindrical hollow structures are uniformly arranged in the circular groove 2 and used for accommodating and limiting seed crystals, the seed crystals 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 grid grooves 3 is 0.9mm. And the adjacent grid grooves 3 are communicated with each other, and particularly, in the embodiment, the adjacent grid grooves 3 are communicated with each other at the connecting 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 basically the same as 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 preparation method of single crystal diamond, which comprises the following steps:
(1) Selecting the seed crystals with approximate height (5 mm multiplied by 0.3 mm), wherein the height difference is less than or equal to 0.09mm. Observing the appearance of the growth surface of the seed crystal in a microscope, and removing unqualified seed crystals. Ultrasonically cleaning qualified seed crystals for 10min by using deionized water, and finally putting the seed crystals into aqua regia for acid cleaning until no bubbles are generated on the surfaces of the seed crystals;
(2) Ultrasonically cleaning the substrate table in the embodiment 1 for 5 to 10min, then plating a layer of carbon film on the upper surface of the substrate table main body, the surface of the circular groove and the surface of the grid groove, wherein the thickness is 10 mu m, ultrasonically cleaning for 3 to 5min after the film plating is finished, and drying by using dry air;
(3) And (2) ultrasonically treating the seed crystal after acid washing in the step (1) for 10min by using deionized water, acetone and absolute ethyl alcohol in sequence, and drying the seed crystal by using dry nitrogen. And (3) putting seed crystals into the grid grooves of the substrate table coated in the step (2) according to the numbers in sequence, and putting the substrate table into the deposition cavity after the seed crystals are placed. Pumping the cavity pressure to be below 0.8Pa, opening a hydrogen valve, setting the hydrogen flow value to be 400sccm, starting microwaves when the pressure rises to 1kPa, setting the microwave power to be 600W, setting the heating speed to be 10 ℃/min, raising the temperature to 900 ℃, setting the pressure rise value to be 17KPa, and etching for 30min;
(4) After etching is finished, introducing methane, carbon dioxide, argon and nitrogen, setting a methane flow value to be 32sccm, a carbon dioxide flow value to be 2sccm, an argon flow value to be 10sccm, a nitrogen flow value to be 0.1sccm, setting a pressure to be 20kPa, keeping the temperature at 950 ℃, and growing for 180 hours;
(5) And after the growth is finished, stopping introducing methane, carbon dioxide, argon and nitrogen, setting the heating speed to 5 ℃/min, heating to 1300 ℃, preserving heat for 1h, then cooling at 2 ℃/min by taking 200 ℃ as a gradient, preserving heat for 1h at each gradient temperature, stopping introducing microwaves to room temperature, and obtaining the single crystal diamond.
Example 4
This example is basically the same as example 3, except that: the single crystal diamond growth substrate stage in example 2 was used.
Example 5
This embodiment is basically the same as embodiment 3, except that: in the step (2), the carbon film has a thickness of 5 μm, a flow rate of carbon dioxide of 0.5sccm, a flow rate of argon of 1sccm, and a flow rate of nitrogen of 0.05sccm.
Example 6
This embodiment is basically the same as embodiment 3, except that: in the step (4), the pressure is 24kPa during growth, and the temperature is 1050 ℃.
Comparative example 1
This embodiment is basically the same as embodiment 3, except that: the substrate table in the embodiment has no circular groove.
Comparative example 2
This example is basically the same as example 4, but different from example 4 in that: the substrate table circular groove depth in the example is 2mm.
Comparative example 3
This embodiment is basically the same as embodiment 3, except that: and (3) removing the step (2).
Comparative example 4
This example is basically the same as example 3, except that: in step (4), the flow rate of carbon dioxide is 4sccm, the flow rate of argon is 10sccm, and the flow rate of nitrogen is 0.1sccm.
Comparative example 5
This embodiment is basically the same as embodiment 3, except that: in the step (4), the flow rate of carbon dioxide is 2sccm, the flow rate of argon is 0.1sccm, and the flow rate of nitrogen is 0sccm.
Comparative example 6
This embodiment is basically the same as embodiment 3, except that: in the step (4), the pressure during growth is 15kPa.
Comparative example 7
This embodiment is basically the same as embodiment 3, except that: in the step (4), the growth temperature is 1100 ℃.
The growth processes of the single crystal diamonds of examples 3 to 6 and comparative examples 1 to 7 were examined, and the results are shown in table 1. It is readily seen from the experimental data table that the temperature difference between the seeds is smaller as the carbon film is thicker. The larger the depth of the circular groove is, the smoother the growth surface is and the more obvious the transverse growth is, but the slower the growth rate is, and the temperature and the pressure have certain influence on the transverse growth.
TABLE 1
The present invention has been described in terms of the preferred embodiment, and it is not intended to be limited to the embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. A method for producing a single crystal diamond, comprising the steps of:
(1) Selecting seed crystals with approximate heights, and carrying out acid washing treatment;
(2) Preparing a substrate table, plating a carbon film on the upper surface of the substrate table, wherein the thickness of the carbon film is 5 to 10 mu m, and cleaning and drying after the film plating is finished;
(3) Placing the seed crystal after acid washing in the step (1) into the substrate table coated with the film obtained in the step (2), placing the substrate table into a deposition cavity, vacuumizing, introducing hydrogen, starting microwaves, and etching for 0.5 to 2h at the temperature of 700 to 1000 ℃ and the pressure of 17 to 21kPa;
(4) After etching is finished, introducing methane, carbon dioxide, argon and nitrogen, and growing for 180 to 200h in an environment with the pressure of 20 to 25kPa and the temperature of 900 to 1050 ℃;
(5) And (3) after the growth is finished, stopping introducing methane, carbon dioxide, argon and nitrogen, increasing the growth temperature in the step (4) by 100 to 150 ℃, preserving the temperature for 1 to 2h, then cooling by taking the temperature of 100 to 200 ℃ as a gradient, preserving the temperature for 1 to 2h at each gradient temperature, cooling to room temperature, closing the microwave, and stopping introducing hydrogen to obtain the monocrystalline diamond.
2. The method according to claim 1, wherein in the step (1), the acid solution is one or more of aqua regia and concentrated sulfuric acid in the acid washing treatment; and acid washing is carried out until no bubbles are generated on the surface of the seed crystal.
3. The preparation method according to claim 1, wherein in the step (1), the seed crystals having a close height are specifically: the height difference between different seed crystals is less than or equal to 0.09mm.
4. The manufacturing method according to claim 1, wherein in the step (2), the substrate stage includes a substrate stage main body of a cylindrical structure or a truncated cone structure, a circular groove is provided on an upper surface of the substrate stage main body, and a plurality of lattice grooves for accommodating the seed crystal are provided on a bottom of the circular groove;
the width of the grid groove is 0.15 to 0.5mm larger than that of the seed crystal, the depth of the grid groove is 0.05 to 0.15mm smaller than that of the seed crystal, and the width of a limiting step between the two grids is 0.9 to 1.5mm; the diameter of the circular groove is 1 to 3mm smaller than the diameter of the upper surface of the substrate table, and the depth of the circular groove is 0.5 to 1mm larger than the difference between the thickness of the seed crystal and the depth of the grid groove.
5. The method of claim 4, wherein a center of the circular recess coincides with a center of the surface of the substrate table body.
6. The method of claim 4, wherein the seed crystal is a square columnar structure, and the lattice grooves are square columnar hollow structures.
7. The manufacturing method according to claim 4, wherein the grid grooves are uniformly provided on an upper surface of the substrate stage 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 arrays, a plurality of layers of circumferential arrays and a plurality of layers of rectangular arrays.
8. The preparation method according to claim 4, wherein the distance between adjacent grid grooves is 0.9 to 1.5mm; the adjacent grid grooves are communicated with each other.
9. The preparation method according to claim 1, wherein in the steps (3) to (5), the flow rate of hydrogen is 400 to 500sccm; in the step (4), the flow rate of methane ranges from 8 to 75sccm, the flow rate of carbon dioxide ranges from 0.5 to 3sccm, the flow rate of argon ranges from 1 to 10sccm, and the flow rate of nitrogen ranges from 0.05 to 0.1sccm.
10. The method according to claim 1, wherein in the steps (3) - (5), the temperature rise rate is 5-20 ℃/min; in the step (5), the cooling rate is 1 to 2 ℃/min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211594172.7A CN115726030A (en) | 2022-12-13 | 2022-12-13 | Preparation method of single crystal diamond |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211594172.7A CN115726030A (en) | 2022-12-13 | 2022-12-13 | Preparation method of single crystal diamond |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115726030A true CN115726030A (en) | 2023-03-03 |
Family
ID=85301186
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211594172.7A Pending CN115726030A (en) | 2022-12-13 | 2022-12-13 | Preparation method of single crystal diamond |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115726030A (en) |
-
2022
- 2022-12-13 CN CN202211594172.7A patent/CN115726030A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN217628727U (en) | Substrate table for growing single crystal diamond | |
| CN102041551B (en) | Base material for growing single crystal diamond and method for producing single crystal diamond substrate | |
| JP6303001B2 (en) | Local carbon supply apparatus and wafer level graphene single crystal manufacturing method by local carbon supply | |
| US9076653B2 (en) | Substrate for growing single crystal diamond layer and method for producing single crystal diamond substrate | |
| CN106868469B (en) | A method of non-metal catalyst prepares graphene in silicon substrate | |
| TW200303580A (en) | Production method of sic monitor wafer | |
| CN102031561A (en) | Base material for growing single crystal diamond and method for producing single crystal diamond substrate | |
| CN215856452U (en) | Single crystal diamond substrate table based on microwave plasma chemical vapor deposition | |
| CN104451868A (en) | Method for manufacturing a single crystal diamond | |
| CN116905084A (en) | Substrate table and method for growing single crystal diamond by microwave plasma chemical vapor deposition technology | |
| Yang et al. | Fabrication of arrays of high-aspect-ratio diamond nanoneedles via maskless ECR-assisted microwave plasma etching | |
| CN217869189U (en) | Substrate table for growth of single crystal diamond | |
| CN216514120U (en) | Substrate table for preparing diamond film based on MPCVD method | |
| CN109573991B (en) | Method for preparing graphene arrays with different lattice point thicknesses by using composite metal template | |
| CN109023517B (en) | Method for eliminating surface defects of single crystal diamond seed crystal by using focused ion beam technology | |
| CN115726030A (en) | Preparation method of single crystal diamond | |
| CN219059207U (en) | Substrate table for single crystal diamond growth | |
| CN211771655U (en) | High-quality diamond growth tray and growth system | |
| CN107522191B (en) | Preparation method of large-size high-quality graphene based on self-limited nucleation growth | |
| CN112609240B (en) | Method for improving heterogeneous epitaxial large-size nucleation uniformity of diamond based on composite structure sample platform | |
| CN112047327B (en) | Preparation method of three-dimensional vertical graphene | |
| CN115110148B (en) | Preparation method of monocrystalline diamond | |
| CN114016005A (en) | Preparation method for co-growth of multiple single crystal diamond sheets | |
| CN116200825A (en) | Preparation method of high-quality monocrystalline diamond for removing polycrystalline defects | |
| CN115058770B (en) | Single crystal diamond manufacturing method for improving growth quantity of CVD single crystal diamond |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |