阅读说明：本技术 一种金刚石纳米毛刺结构的制备方法 (Preparation method of diamond nano burr structure ) 是由 张锦文 林晨 于 2021-06-21 设计创作，主要内容包括：本发明涉及一种金刚石纳米毛刺结构的制备方法,包括：提供衬底；在所述衬底上形成纳米晶金刚石薄膜；以及将形成有纳米晶金刚石薄膜的衬底在含氧气氛中退火,得到金刚石纳米毛刺结构。本发明方法可制备具有纳米级密排结构的纳米晶金刚石薄膜,该薄膜生长速率快,并且利用该薄膜通过高选择比的氧化反应可容易地获得大长径比、高密度的金刚石纳米毛刺结构。本发明方法中的高选择比的氧化反应使得金刚石消耗量小。另外,本发明方法的设备和工艺简单,可大大降低加工成本。(The invention relates to a preparation method of a diamond nano burr structure, which comprises the following steps: providing a substrate; forming a nanocrystalline diamond film on the substrate; and annealing the substrate with the nanocrystalline diamond film in an oxygen-containing atmosphere to obtain the diamond nano burr structure. The method can prepare the nanocrystalline diamond film with a nano-scale close-packed structure, the film has high growth rate, and the diamond nano burr structure with large length-diameter ratio and high density can be easily obtained by utilizing the film through the oxidation reaction with high selection ratio. The high selectivity of the oxidation reaction in the method of the invention results in a low diamond consumption. In addition, the method has simple equipment and process and can greatly reduce the processing cost.)

1. A preparation method of a diamond nano burr structure is characterized by comprising the following steps:

providing a substrate;

forming a nanocrystalline diamond film on the substrate; and

and annealing the substrate with the nanocrystalline diamond film in an oxygen-containing atmosphere to obtain the diamond nano burr structure.

2. The production method according to claim 1, wherein the diamond nanoprotrusions have a large aspect ratio.

3. A production method according to claim 1 or 2, characterized in that the substrate is diamond, silicon, GaN, SiC, BN, Ir, or stainless steel.

4. A production method according to claim 1 or 2, characterized in that, before the nanocrystalline diamond film is formed, the surface of the substrate is subjected to a pretreatment of seeding, mechanical scraping, ultrasonic scraping, pulsed laser irradiation, ion implantation, pre-deposited graphite, or pre-deposited amorphous carbon.

5. The production method according to claim 1 or 2, wherein the nanocrystalline diamond film is formed on the substrate by a chemical vapor deposition method.

6. The production method according to claim 5, wherein the nanocrystalline diamond film having the dense vertically arranged diamond phase nano-skeleton structure is formed on the substrate by adjusting process parameters of a chemical vapor deposition method, the process parameters including a working atmosphere, a working gas pressure, a power, a substrate temperature, a hot wire temperature, and a bias voltage.

7. The method according to claim 5 or 6, wherein the chemical vapor deposition method is a microwave plasma chemical vapor deposition method, a radio frequency chemical vapor deposition method, a direct current arc chemical vapor deposition method, a hot wire chemical vapor deposition method, or a bias enhanced chemical vapor deposition method.

8. The production method according to claim 1 or 2, wherein the oxygen-containing atmosphere is an air atmosphere or a mixed atmosphere of oxygen and an inert gas.

9. The production method according to claim 8, wherein the mixed atmosphere is a mixed atmosphere of oxygen and nitrogen, a mixed atmosphere of oxygen and argon, or a mixed atmosphere of oxygen and helium.

10. The production method according to claim 1 or 2, wherein the annealing temperature is 400 ℃ or higher.

Technical Field

The invention relates to the field of diamond nano structures, in particular to a preparation method of a diamond nano burr structure.

Background

Diamond has a high refractive index, low absorption, and extremely high hardness, thermal conductivity, and corrosion resistance. The micro-nano structure of the diamond is beneficial to enhancing the material characteristics, and the diamond has excellent performance in the aspects of super-capacitor or electrochemical sewage treatment electrodes, field emission devices, ion filter sieves and the like. Diamond nanostructures include nanoporous films, nanocolumns, diamond foam, nanofabrics, and nanofiber films, among others. The diamond has high hardness and extremely strong chemical inertia, so the preparation of the micro-nano structure is difficult. At present, the preparation method of the diamond nano structure mainly comprises reactive ion etching and electrochemical corrosion. These production methods have disadvantages of low selectivity and large diamond consumption. Therefore, it is required to develop a method for preparing a diamond nanostructure having a high selectivity ratio and a small diamond consumption.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a diamond nano burr structure, which has the advantages of high selection ratio, small diamond consumption, simple equipment and process and capability of greatly reducing the processing cost.

In order to achieve the above object, the present invention provides the following technical solutions.

A method for preparing a diamond nano burr structure comprises the following steps:

providing a substrate;

forming a nanocrystalline diamond film on the substrate; and

and annealing the substrate with the nanocrystalline diamond film in an oxygen-containing atmosphere to obtain the diamond nano burr structure.

Compared with the prior art, the invention achieves the following technical effects:

1. the method can prepare the nanocrystalline diamond film with a nano-scale close-packed structure, the film has high growth rate, and the diamond nano burr structure with large length-diameter ratio and high density can be easily obtained by utilizing the film through the oxidation reaction with high selection ratio.

2. The high selectivity of the oxidation reaction in the method of the invention results in a low diamond consumption.

3. The method has simple equipment and process and can greatly reduce the processing cost.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 and fig. 2 are schematic diagrams of structures obtained in each step in the preparation method provided in example 1 of the present invention.

Fig. 3 and 4 are scanning electron microscope images of the structure obtained at each step in the manufacturing method provided in example 1 of the present invention.

FIG. 5 is a scanning electron microscope photograph of the structure obtained in comparative example 1 of the present invention.

Description of the reference numerals

100 is a substrate, 200 is a nanocrystalline diamond film, 300 is a diamond phase nano-skeleton, 400 is non-diamond phase carbon, and 500 is diamond nano-burr.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.

Various structural schematics according to embodiments of the present disclosure are shown in the figures. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers, and relative sizes and positional relationships therebetween shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, as actually required.

In the context of the present disclosure, when a layer/element is referred to as being "on" another layer/element, it can be directly on the other layer/element or intervening layers/elements may be present. In addition, if a layer/element is "on" another layer/element in one orientation, then that layer/element may be "under" the other layer/element when the orientation is reversed.

As described above, the present invention provides a method for preparing a diamond nanopunch structure, which includes the following steps.

Providing a substrate;

the substrate of the present invention may be diamond, silicon, GaN, SiC, BN, Ir, stainless steel, or the like. The silicon substrate includes an N-type or P-type silicon substrate. The substrate of the present invention can be directly purchased from the market. The substrate is first cleaned before it is used. The cleaning method of the present invention is not particularly limited, and a cleaning method commonly used in the art, such as wet cleaning, dry cleaning, cleaning using a chelating agent, ozone cleaning, or low-temperature spray cleaning, may be employed. The wet cleaning may be an RCA cleaning process, and the dry cleaning may be a plasma dry cleaning.

After cleaning, the substrate surface is preferably pretreated to increase the nucleation density of the diamond. The pretreatment method of the present invention may be seed implantation, mechanical scraping, ultrasonic scraping, pulsed laser irradiation, ion implantation, pre-deposition of graphite, or pre-deposition of amorphous carbon, etc. In a preferred embodiment of the present invention, the pretreatment step is carried out by seeding, and specifically comprises: the substrate was placed in a suspension containing diamond nanoparticles and subjected to sonication. The suspension is a suspension of diamond nanoparticle powder with a diameter of 2nm or more in a solvent. The solvent may be water, absolute ethanol, toluene or other organic solvents. The ultrasound time is preferably 30min or more. After the implantation of the seed, the substrate is preferably cleaned and dried. For example, the substrate may be ultrasonically cleaned in anhydrous ethanol and blown dry with dry air or nitrogen.

And forming a nanocrystalline diamond film on the substrate.

The present invention forms a nanocrystalline diamond film on a substrate by Chemical Vapor Deposition (CVD). The chemical vapor deposition method is Microwave Plasma Chemical Vapor Deposition (MPCVD), Radio Frequency Chemical Vapor Deposition (RFCVD), direct current arc chemical vapor deposition (DCCVD), hot wire chemical vapor deposition (HFCVD), bias enhanced chemical vapor deposition (PECVD), or the like. The nanocrystalline diamond film of the invention has a diamond phase nano skeleton structure which is densely and vertically arranged, and the skeleton is composed of non-diamond phase carbon. The nanocrystalline diamond film (with a special crystallographic structure) with the diamond phase nano-skeleton structure densely and vertically arranged can be formed on the substrate by adjusting the process parameters of the chemical vapor deposition method, wherein the process parameters comprise working atmosphere, working air pressure, power, substrate temperature, hot wire temperature, bias voltage and the like. The growth process parameters of the nanocrystalline diamond film have an important influence on the formation of the nano burr structure.

In a preferred embodiment, the nanocrystalline diamond film is formed on the substrate by microwave plasma chemical vapor deposition. The growth process parameters of the nanocrystalline diamond film comprise: working atmosphere 20% CH₄And 80% of H₂The substrate temperature is 700 ℃, the microwave power is 1800W, and the working air pressure is 6 kPa. CH in the preparation of nanocrystalline diamond films by microwave plasma chemical vapor deposition₄As a carbon source, carbon groups resulting from dissociation thereof are deposited on a substrate, and H₂The etching action of (a) is balanced and restricted. The invention prepares the nanocrystalline diamond film with a nano-scale close packing structure by controlling the technological parameters of the microwave plasma chemical vapor deposition method, including working atmosphere, substrate temperature, microwave power and working air pressure, and can prepare the nano-diamond burr structure with large length-diameter ratio and high density based on the film.

And annealing the substrate with the nanocrystalline diamond film in an oxygen-containing atmosphere to obtain the diamond nano burr structure.

The oxygen-containing atmosphere of the present invention may be an air atmosphere or a mixed atmosphere of oxygen and an inert gas. The mixed atmosphere may be a mixed atmosphere of oxygen and nitrogen, a mixed atmosphere of oxygen and argon, or a mixed atmosphere of oxygen and helium. Oxygen in an oxygen-containing atmosphere acts as an oxidant and can undergo an oxidation reaction with the non-diamond phase carbon at high temperatures, thereby converting it to carbon dioxide or carbon monoxide for removal. The annealing temperature of the invention is above 400 ℃, and the annealing time is determined according to the annealing temperature and the required burr height. The annealing step can be performed in a variety of thermal processing equipment including, but not limited to, muffle furnaces, ovens, and the like.

The preparation of the diamond nano burr structure with large length-diameter ratio requires anisotropic etching with high selection ratio, so the preparation difficulty is very high. The invention adopts an oxidation annealing method to remove the non-diamond phase carbon part in the nanocrystalline diamond film, thereby forming the diamond nano burr structure with large length-diameter ratio. Compared with the reactive ion etching technology, the method has the following advantages: the selection ratio is high, the consumption of the diamond is low, the equipment and the process are simple, and the processing cost can be greatly reduced. In addition, the method need not be limited to highly conductive doped diamond as with electrochemical etching techniques.

The diamond nano burr structure prepared by the method has the characteristics of large length-diameter ratio and high density. Specifically, the aspect ratio of the diamond nanoprobe is preferably more than 1, and the distribution density of the diamond nanoprobe on the substrate is 1.0X 10⁹cm^-2The above.

The invention will be further illustrated with reference to specific embodiments and the accompanying drawings.

Example 1

In single-throw N type<100>On a monocrystalline silicon wafer 100, a nanocrystalline diamond film 200 with diamond phase nano-frameworks 300 arranged densely and vertically is grown by MPCVD, which comprises the following steps: (1) putting the diamond nano-particle powder with the diameter of 50nm into a proper amount of absolute ethyl alcohol, and carrying out ultrasonic treatment for 1 h; (2) putting the cleaned monocrystalline silicon wafer into the suspension, and carrying out ultrasonic treatment for more than 30 min; (3) putting the silicon chip into two cups of absolute ethyl alcohol in sequence, and ultrasonically cleaning the silicon chip for 30s respectively; (4) the silicon wafer is taken out and dried by dry air. (5) Putting a silicon wafer into MPCVD equipment, wherein the growth process parameters are as follows: working atmosphere 20% CH₄And 80% of H₂The substrate temperature is 700 ℃, the microwave power is 1800W, the working pressure is 6kPa, the growth time is 3h, the structure shown in figure 1 is obtained, and the scanning electron microscope picture is shown in figure 3.

Annealing to remove non-diamond phase carbon 400 between diamond phase nano-skeletons 300, comprising the following steps: placing the monocrystalline silicon wafer 100 on which the nanocrystalline diamond film 200 is grown into a quartz boatAnd pushed into a muffle furnace, the atmosphere is air, the annealing temperature is 550 ℃, the annealing time is 150min, the structure shown in figure 2 is obtained, and the scanning electron microscope picture of the structure is shown in figure 4. The average length of the diamond nano burr is about 180nm, the diameter is less than 10nm, namely the length-diameter ratio is more than 18, and the distribution density of the diamond nano burr on the substrate is 1.8 multiplied by 10⁹cm^-2This indicates that it has a large aspect ratio and a high density of structural features.

Comparative example 1

This comparative example was carried out as described in example 1, except that the working atmosphere was 20% CH₄10% of H₂And 70% argon at 800 deg.C with a power of 2100W and a working pressure of 8 kPa. The resulting structure after annealing is shown in fig. 5, and it can be seen that no nanoprobe is formed.

As can be seen from example 1 and comparative example 1, the growth process parameters of the nanocrystalline diamond film have an important influence on the formation of the nanophase burr structure.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.