Method for preparing patterned diamond, article having patterned diamond and applications thereof

Abstract

This application relates to the field of diamond material preparation, and provides a method for preparing patterned diamond, a product with patterned diamond and its applications. The method for preparing the patterned diamond includes: disposing an insulating substrate on the surface of a growth substrate, the insulating substrate having a patterned area, the surface including an exposed area exposed through the patterned area, and the exposed area and the patterned area together constituting a growth area for diamond; performing chemical vapor deposition on the growth substrate and applying a bias electric field to generate diamond in the growth area to form patterned diamond. The method of this application can prepare patterned diamond with a high aspect ratio.

Description

Technical Field

[0001] The present application relates to the field of diamond material preparation, and in particular to a method for preparing patterned diamond, a product having patterned diamond, and applications thereof. Background Art

[0002] Nano or micro-electromechanical systems have become an important technology in many application fields such as chemical, biological and mass sensors. Diamond is an ideal material for high-performance MEMS (micro-electromechanical systems) devices due to its excellent properties. For example, diamond has extremely high Young's modulus, highest hardness, hydrophobic surface and extremely high thermal conductivity, and has high corrosion resistance to corrosive chemicals and good biocompatibility. However, these performance advantages of diamond have also become one of the serious barriers to its surface patterning. Due to the extremely high hardness and good chemical stability of diamond, conventional silicon-based material processing technology is difficult to meet the requirements of diamond-based MEMS processing.

[0003] At present, the main methods for diamond surface patterning include selective nucleation, laser processing, focused ion beam processing and reactive ion etching. 1) Selective nucleation technology: First, spin-coat the photoresist on a silicon wafer or other diamond nucleation substrate, remove the photoresist of the patterned part by photolithography to obtain a patterned surface, and then nucleate on the patterned substrate surface to obtain a patterned diamond film; however, the MEMS prepared by this technology has poor precision, and the precision depends entirely on the chemical vapor deposition process of diamond, and it is difficult to obtain a smooth surface. 2) Laser processing technology: Diamond substrates are processed by high-energy laser beams to directly prepare MEMS devices; this technology can process some three-dimensional structures, but the high-energy laser beam will ablate the diamond surface during the processing, affecting the quality of MEMS; at the same time, the aspect ratio of laser processing depends on its processing power and beam spot diameter. High power and large beam spot can achieve higher processing capabilities, but this is accompanied by a wider processing width, so the aspect ratio of laser processing is generally lower than 20:1. 3) Focused ion beam processing: Diamond substrates are bombarded with focused gallium ions to achieve material removal, and then diamond-based MEMS are obtained; this method has high processing accuracy, and when used with a scanning electron microscope, the processing process can be observed in real time, and three-dimensional structure MEMS can also be obtained to a certain extent; however, focused ion beam equipment is expensive and has low processing efficiency. At the same time, as the processing depth increases, the ion beam processing capability also weakens, so its processing aspect ratio is basically below 10:1. 4) Reactive ion etching: Diamond is etched by oxygen, fluorine plasma, etc., and the diamond surface can be patterned in combination with photolithography and other technologies; this technology can achieve large-area, high-precision diamond surface patterning, but its etching depth is relatively low, generally less than 10:1, and it has strong orientation anisotropy, which will affect the processing accuracy.

[0004] Therefore, the development of a new method for fabricating patterned diamond with high aspect ratio and high precision is crucial for improving the application of diamond in the MEMS industry. Summary of the Invention

[0005] Based on this, the object of the present application is to provide a method for fabricating patterned diamond, an article with patterned diamond prepared by this fabrication method, and the application of the article with patterned diamond.

[0006] The first aspect of the present application provides a method for fabricating patterned diamond, and the fabrication method includes:

[0007] An insulating substrate is disposed on the surface of the growth substrate. The insulating substrate has a pattern area, and the surface includes an exposed area exposed through the pattern area. The exposed area and the pattern area together constitute the growth area of diamond. Chemical vapor deposition is performed on the growth substrate, and a bias electric field is applied to generate diamond in the growth area to form patterned diamond.

[0008] Optionally, the growth substrate is a silicon wafer or a molybdenum wafer.

[0009] Optionally, before disposing the insulating substrate on the surface of the growth substrate, the fabrication method further includes: performing pretreatment on the growth substrate, and the pretreatment includes the following steps:

[0010] Grind the growth substrate with nano-diamond powder;

[0011] Place the ground growth substrate into a dispersion liquid of nano-diamond powder for ultrasonic treatment.

[0012] Optionally, the material of the insulating substrate is alumina or quartz, the pattern area is a nano-wire array, a comb-shaped electrode array, a micro-gear array or a micro-spring array, and the thickness of the insulating substrate is 10μm - 200μm.

[0013] Optionally, the chemical vapor deposition is hot-filament chemical vapor deposition. Among them, the heating filament is a tantalum wire or a tungsten wire, the number of heating filaments is 3 - 6, and the single-filament power is 900W - 1.5kW.

[0014] Furthermore, the single-filament power is 1.0kW - 1.4kW.

[0015] Optionally, during the process of generating diamond, the conditions of the hot-filament chemical vapor deposition include: the growth atmosphere is hydrogen, methane and an inert gas, the flow rate of hydrogen is 200sccm - 500sccm, the flow rate of methane is 3% - 10% of the flow rate of hydrogen, the flow rate of the inert gas is 8% - 30% of the flow rate of hydrogen, and the growth pressure is 2.5kP - 4.5kPa.

[0016] Optionally, during the process of generating diamond, the conditions for applying the bias electric field include: the power supply voltage is 50V - 300V, and the application time is 50 hours - 400 hours.

[0017] Optionally, the heating wire is a heat-treated heating wire, and the heat treatment is carried out in a mixed gas containing hydrogen and methane. The conditions for the heat treatment include: the heat treatment pressure is 1kPa - 3kPa, the heat treatment time is 10 minutes - 50 minutes, the hydrogen flow rate is 200sccm - 500sccm, and the methane flow rate is 3% - 8% of the hydrogen flow rate.

[0018] Optionally, after forming the patterned diamond, the preparation method further includes: removing the insulating substrate through an etching process.

[0019] The second aspect of the present application provides an article with patterned diamond prepared by the preparation method described in the first aspect of the present application.

[0020] The third aspect of the present application provides the application of the article with the patterned diamond film described in the second aspect of the present application in micro electro - mechanical systems, microsensors, or microfabrication.

[0021] The beneficial effect of the present application is that the method of the present application can prepare patterned diamond with high aspect ratio and high precision, and can prepare large - size substrates of inch - level, avoiding the problem of difficult processing of diamond, and providing a new way for the preparation of diamond - based MEMS.

[0022] Other features and advantages of the present application will be described in detail in the following specific implementation section. Brief Description of the Drawings

[0023] Figure 1 Schematic diagram of the preparation principle of patterned diamond for an embodiment of the present application;

[0024] Figure 2 Schematic diagram of the graphic structure of the insulating substrate used in Example 1;

[0025] Figure 3 Schematic diagram of the graphic structure of the insulating substrate used in Example 2. Detailed Description of the Preferred Embodiments

[0026] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the description of this application herein are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0028] In a first aspect, this application provides a method for preparing patterned diamond, and the preparation method includes:

[0029] An insulating substrate is provided on the surface of the growth substrate, the insulating substrate has a patterned area, the surface includes an exposed area exposed through the patterned area, and the exposed area and the patterned area together form a growth area for diamond;

[0030] Chemical vapor deposition is performed on the growth substrate, and a bias electric field is applied to generate diamond in the growth area to form the patterned diamond.

[0031] In this application, the growth substrate can be various substrates that are beneficial to diamond nucleation. In some embodiments, the growth substrate is a silicon wafer or a molybdenum wafer. The silicon wafer is, for example, a single crystal silicon wafer.

[0032] In some embodiments, before the insulating substrate is provided on the surface of the growth substrate, the preparation method further includes: pretreating the growth substrate, and the nucleation density of the growth substrate can be further improved through the pretreatment. Among them, the pretreatment includes the following steps:

[0033] The growth substrate is ground with nano-diamond powder and then ultrasonically treated in a dispersion liquid of nano-diamond powder. Through the grinding, the surface roughness of the growth substrate can be increased. Generally, the surface roughness Ra of the substrate on which diamond is to be grown can be 1 μm - 10 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm. The particle size of the nano-diamond powder can be 100 nm - 1000 nm, and the grinding time can be 3 minutes - 10 minutes. Optionally, before the ultrasonic treatment, the pretreatment further includes: washing the ground growth substrate with water.

[0034] In some embodiments, the solvent in the dispersion of the nanodiamond powder is ethanol, and the concentration of the nanodiamond powder in the dispersion is 2 g / mL - 10 g / mL, such as 2 g / mL, 3 g / mL, 4 g / mL, 5 g / mL, 6 g / mL, 7 g / mL, 8 g / mL, 9 g / mL or 10 g / mL. The time of the ultrasonic treatment can be 5 minutes - 20 minutes, such as 5 minutes, 8 minutes, 10 minutes, 12 minutes, etc. The ultrasonic frequency of the ultrasonic treatment can be 30 kHz - 100 kHz, such as 50 kHz, 60 kHz, 70 kHz, 80 kHz, 85 kHz, 90 kHz, etc.

[0035] In this application, the material of the insulating substrate can be various insulating and easily processable materials. Due to its insulation property, the insulating substrate can change the direction of the electric field lines during the diamond generation process, causing the positive ions generated during the chemical vapor deposition process to move into the patterned area of the insulating substrate. Additionally, due to its easy processability, a large-area mask layer (insulating substrate) can be arranged on the growth substrate to achieve the preparation of large-area patterned diamond. In some embodiments, the material of the insulating substrate is alumina or quartz.

[0036] In this application, the patterned area on the insulating substrate can have various common patterns on masks, and can be specifically selected according to the usage requirements of the diamond, such as various through-hole array patterns.

[0037] In some embodiments, the patterned area is a nanowire array, a comb-shaped electrode array, a gear structure, a micro-gear array or a micro-spring array.

[0038] In some specific embodiments, the patterned area of the insulating substrate is a nanowire array, and the diameter of the nanowires in the nanowire array is 200 nm - 1000 nm, such as 200 nm, 300 nm, 400 nm, 500 nm, etc.

[0039] In some other specific embodiments, the patterned area of the insulating substrate is a comb-shaped electrode array, and the width of a single comb tooth is 100 nm - 1000 nm, such as 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, etc.

[0040] In this application, the thickness of the insulating substrate can be 20 μm - 500 μm. To further improve the uniformity of the formed patterned diamond, it is preferred that the thickness of the insulating substrate is 20 μm - 200 μm, such as 20 μm, 50 μm, 55 μm, 60 μm, 70 μm, 80 μm, 100 μm, etc.

[0041] It should be noted that the preparation method of the present application is particularly suitable for preparing graphitized diamond with a high aspect ratio. The aspect ratio is determined by the insulating substrate, where the "aspect ratio" refers to the ratio of the thickness of the insulating substrate to the width (diameter) of the narrowest gap in the array pattern. In some embodiments, the aspect ratio of the insulating substrate is (80 - 300):1.

[0042] In the present application, under the action of a bias electric field, during the chemical vapor deposition process, positively charged groups generated from the carbon source will deposit in the growth region to form diamond. Optionally, the chemical vapor deposition is hot filament chemical vapor deposition (HFCVD), that is, under the action of a bias electric field, diamond is prepared by hot filament chemical vapor deposition. During the hot filament chemical vapor deposition process, the high temperature generated by the heating filament dissociates the gas source containing the carbon source and hydrogen, generating positively charged carbon-containing groups, hydrogen ions and negatively charged electrons. At this time, the ionization region around the heating filament is electrically neutral, and the carbon-containing groups deposit on the growth substrate (specifically in the growth region) to form diamond, but graphite phase is also generated at the same time. The hydrogen ions are used to etch the graphite, leaving diamond.

[0043] In the present application, the heating filament can be a tantalum wire or a tungsten wire, and the carbon source is, for example, methane. Preferably, the number of heating filaments is 3 - 6 (such as 4, 5, 6); the power of a single filament is 900W - 1.5kW (such as 900W, 1kW, 1.1kW, 1.2kW, 1.3kW, 1.4kW, 1.5kW), and preferably the power of a single filament is 1.0kW - 1.4kW, so as to further reduce the generation of graphite phase and improve the quality of diamond.

[0044] In the present application, the insulating substrate can be arranged on the surface of the growth substrate by means of edge clamping or the like.

[0045] In some embodiments, during the process of generating diamond, the conditions of the hot filament chemical vapor deposition include: the growth atmosphere is hydrogen, methane and an inert gas, the flow rate of hydrogen is 200sccm - 500sccm, such as 200sccm, 300sccm, 400sccm, 450sccm or 500sccm; the flow rate of methane is 3% - 10% of the flow rate of hydrogen, such as 3%, 4%, 5%, 6%, 7%, 8% or 10% of the flow rate of hydrogen; the flow rate of the inert gas is 8% - 30% of the flow rate of hydrogen, such as 10%, 15%, 20% or 25% of the flow rate of hydrogen; the growth pressure is 2.5kPa - 4.5kPa, such as 2.5kPa, 3kPa, 3.5Pa, 4kPa or 4.5kPa,. The inert gas is, for example, nitrogen or argon.

[0046] Optionally, during the process of generating diamond, the heating filament is 6mm - 12mm away from the insulating substrate.

[0047] In some embodiments, the conditions of the bias electric field include: the power supply voltage is 50V - 300V, such as 50V, 80V, 100V, 120V, 150V, 180V, 200V, 210V, 260V, 300V, etc.; the application time is 50 hours - 400 hours, such as 50 hours, 55 hours, 60 hours, 80 hours, 100 hours, 200 hours, 260 hours, 300 hours, etc. Preferably, the power supply voltage is 100V - 200V, so that diamond can be effectively deposited in the graphic area and the growth rate can be avoided from being too fast to generate gaps, thereby affecting the quality of diamond.

[0048] In some embodiments, in order to improve the stability and service life of the heating wire, preferably, the heating wire is a heat-treated heating wire. The carbonization treatment is carried out in a mixed gas containing hydrogen and methane. The conditions of the carbonization treatment include: the carbonization pressure is 1kPa - 3kPa, such as 1kPa, 1.5kPa, 2kPa, 2.5kPa, 3kPa; the carbonization time is 10 minutes - 50 minutes, such as 10 minutes, 12 minutes, 15 minutes, 20 minutes, 22 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes; the hydrogen flow rate is 200sccm - 500sccm, such as 200sccm, 300sccm, 350sccm, 400sccm, 450sccm or 500sccm; the flow rate of methane is 3% - 8% of the hydrogen flow rate, such as 3%, 4%, 5%, 6%, 7% or 8% of the hydrogen flow rate.

[0049] Figure 1 FIG. is a schematic diagram of the principle for preparing patterned diamond in one embodiment. The deposition equipment used is a hot filament chemical vapor deposition equipment. By suspending a tantalum wire with a high melting point above the growth substrate as a heat source and heating it to a high temperature (such as 2000°C - 2400°C) by electrifying it, the super-high temperature dissociates the reaction gas (mainly CH 4 and H 2 ) to generate active particles such as carbon-containing groups and hydrogen atoms; at the same time, a negative electric field is applied at the bottom of the equipment substrate stage to attract the positive ions in the ionization region to accelerate and move towards the substrate stage. By arranging a patterned insulating substrate above the diamond growth substrate, the direction of the electric field lines can be changed, so that the negatively charged electrons move in the direction away from the substrate stage, while the positive ions (CH x + and H + ) move towards the graphic area of the insulating substrate, thereby forming patterned diamond.

[0050] In some embodiments, after forming the patterned diamond, the preparation method further includes: removing the insulating substrate through an etching process. Additionally, according to the usage requirements of the product, the preparation method further includes or does not include the step of removing the growth substrate.

[0051] According to a specific embodiment, the preparation method of the patterned diamond includes the following steps:

[0052] S0: Grind the growth substrate with nano-diamond powder, then place it in an ethanol dispersion of nano-diamond for ultrasonic treatment, subsequently clean it in alcohol, and then dry it with nitrogen;

[0053] S1: Place the growth substrate processed in step S0 on the molybdenum stage (connected to the negative pole of an external power supply through a wire) of a hot filament chemical vapor deposition device equipped with tantalum wire, and arrange a patterned insulating substrate on the surface of the growth substrate away from the molybdenum stage; then connect the tantalum wire to the positive and negative poles of the device power supply, and subsequently turn on the vacuum pump to pump the cavity to the base vacuum;

[0054] S2: Introduce hydrogen and methane into the hot filament chemical vapor deposition device to carbonize the tantalum wire. After the carbonization is completed, continue to introduce an inert gas, turn on the bias power supply, and start the growth of diamond.

[0055] In a second aspect, the present application provides an article with patterned diamond prepared by the preparation method.

[0056] According to the present application, the prepared article with patterned diamond is a patterned diamond; or, the prepared article with patterned diamond is a growth substrate with the patterned diamond.

[0057] In a third aspect, the present application provides the application of the article with patterned diamond in micro-optoelectromechanical systems, microsensors or microfabrication.

[0058] The following uses specific examples to illustrate the present application.

[0059] In the following examples and comparative examples, the growth substrate used is a single crystal silicon substrate with a diameter of 25 mm, and diamond is chemically vapor deposited on the (100) plane of the substrate.

[0060] The growth atmosphere is hydrogen, methane and nitrogen. The volume purity of hydrogen is 99.9%, the volume of methane is 99.99%, and the volume of nitrogen is 99.9%.

[0061] Example 1

[0062] The silicon wafer was polished with nano-diamond powder for 5 minutes to make the roughness Ra of the (100) plane 10 μm. The polished silicon wafer was placed in an ethanol dispersion of nano-diamond powder (the concentration of nano-diamond powder was 3 g / mL), ultrasonicated at 60 kHz for 8 minutes, then washed with alcohol and dried with nitrogen to obtain the treated silicon wafer;

[0063] The treated silicon wafer was placed on the molybdenum stage of a hot-wire chemical vapor deposition equipment equipped with tantalum wires. An alumina substrate with a circular through-hole array (as Figure 2 shown) was placed on the surface of the silicon wafer as an insulating substrate. The diameter of the insulating substrate was 25 mm, the thickness was 60 μm, and the through-hole diameter was 400 nm; Four tantalum wires with a diameter of 0.5 mm were connected to the positive and negative poles of the equipment power supply, and the molybdenum stage was adjusted to keep it directly below the tantalum wires and the insulating substrate was 8 mm away from the tantalum wires;

[0064] Hydrogen and methane were introduced into the hot-wire chemical vapor deposition equipment to carbonize the tantalum wires; The carbonization pressure was 2 kPa, the hydrogen flow rate was 400 sccm, the methane flow rate was 6% of the hydrogen flow rate, the carbonization time was 30 minutes, and the power of each tantalum wire was 1.2 kW;

[0065] After carbonization, keeping the hydrogen and methane flow rates and the tantalum wire power unchanged, nitrogen with a flow rate of 10% of the hydrogen flow rate was introduced, the growth pressure was increased to 2.5 kPa, then the bias power supply was turned on, the power supply voltage was 150 V, and the growth time was 60 hours to obtain a diamond nanowire array. The aspect ratio of the diamond nanowire array was 150:1. Observed by scanning electron microscopy, its surface was flat. The sidewall roughness Ra < 10 nm was measured by a white light interferometer. It was found by Raman spectrometer that the content of graphite phase in the preparation was less than 3% (counted by C atom number). The low content of graphite phase indicated that the deposited diamond had high quality.

[0066] Example 2

[0067] The silicon wafer was polished with nano-diamond powder for 5 minutes to make the roughness Ra of the (100) plane 10 μm. The polished silicon wafer was placed in an ethanol dispersion of nano-diamond powder (the concentration of nano-diamond powder was 3 g / mL), ultrasonicated at 60 kHz for 8 minutes, then washed with alcohol and dried with nitrogen to obtain the treated silicon wafer;

[0068] The treated silicon wafer was placed on the molybdenum stage of a hot-wire chemical vapor deposition equipment equipped with tantalum wires. An alumina substrate with a circular through-hole array (as Figure 2 shown) was placed on the surface of the silicon wafer as an insulating substrate. The diameter of the insulating substrate was 25 mm, the thickness was 60 μm, and the through-hole diameter was 400 nm; Four tantalum wires with a diameter of 0.5 mm were connected to the positive and negative poles of the equipment power supply, and the molybdenum stage was adjusted to keep it directly below the tantalum wires and the insulating substrate was 8 mm away from the tantalum wires;

[0069] Hydrogen and methane are introduced into the hot wire chemical vapor deposition equipment to carbonize the tantalum wire; the carbonization pressure is 2 kPa, the hydrogen flow rate is 400 sccm, the methane flow rate is 6% of the hydrogen flow rate, the carbonization time is 30 minutes, and the power of each tantalum wire is 900 W;

[0070] After carbonization is completed, while keeping the hydrogen and methane flow rates and the tantalum wire power unchanged, nitrogen with a flow rate of 10% of the hydrogen flow rate is introduced, the growth pressure is increased to 2.5 kPa, then the bias power supply is turned on, the power supply voltage is 150 V, and the growth time is 60 hours to obtain a diamond nanowire array. The aspect ratio of the diamond nanowire array is 150:1. Observed by scanning electron microscopy, its surface is flat. The sidewall roughness Ra < 10 nm is measured by a white light interferometer. It is found by Raman spectrometer that the content of the prepared graphite phase is less than 5% (counted by the number of C atoms). The low content of the graphite phase indicates that the quality of the deposited diamond is high.

[0071] Comparative Example 1

[0072] The diamond nanowire array is prepared according to the method of Example 1, except that no bias electric field is applied. Specifically, after carbonizing the tantalum wire, while keeping the hydrogen and methane flow rates and the tantalum wire power unchanged, nitrogen with a flow rate of 10% of the hydrogen flow rate is introduced, the growth pressure is increased to 2.5 kPa, and growth starts. After 2 h of growth, it is found that no diamond is deposited on the silicon wafer, indicating that due to the too high aspect ratio, the carbon-containing groups cannot enter the interior of the nanopores without applying a bias voltage.

[0073] Example 3

[0074] The silicon wafer is polished with nano-diamond powder for 3 minutes to make the roughness Ra of the (100) plane 5 μm. The polished silicon wafer is placed in an ethanol dispersion of nano-diamond powder (the concentration of nano-diamond powder is 3 g / mL), sonicated at 50 kHz for 10 minutes, then washed with alcohol and dried with nitrogen to obtain a treated silicon wafer;

[0075] The treated silicon wafer is placed on the molybdenum stage of the hot wire chemical vapor deposition equipment equipped with tantalum wires, and an alumina substrate with a comb-shaped patterned through-hole is placed above the silicon wafer as an insulating substrate. The diameter of the insulating substrate is 25 mm and the thickness is 60 μm. The comb-shaped structure is as Figure 3 shown. The width of the main comb teeth is 1 μm and the length is 40 μm. The width of a single comb tooth is 200 nm and the length is 30 μm. Keep the insulating substrate 10 mm away from the tantalum wire; Four tantalum wires with a diameter of 0.5 mm are connected to the positive and negative poles of the equipment power supply, and the molybdenum stage is adjusted to keep it directly below the tantalum wire and the insulating substrate 10 mm away from the tantalum wire;

[0076] Hydrogen and methane are introduced into a hot-wire chemical vapor deposition apparatus to carbonize tantalum wires; the carbonization pressure is 2 kPa, the hydrogen flow rate is 400 sccm, the methane flow rate is 6% of the hydrogen flow rate, the carbonization time is 30 minutes, and the power of each tantalum wire is 1.2 kW;

[0077] After carbonization is completed, while keeping the hydrogen, methane flow rates and the tantalum wire power unchanged, nitrogen gas with a flow rate of 20% of the hydrogen flow rate is introduced, the growth pressure is increased to 3 kPa, then the bias power supply is turned on, the power supply voltage is 150 V, and the growth time is 300 hours to obtain a comb-shaped diamond electrode array. The aspect ratio of the comb-shaped diamond electrode array is 300:1. Observed by scanning electron microscopy, its surface is flat, the sidewall roughness Ra < 8 nm, and the graphite phase content is tested by Raman spectroscopy to be below 3% (counted by the number of C atoms). The low graphite phase content indicates that the quality of the deposited diamond is high.

[0078] Comparative Example 2

[0079] The comb-shaped diamond electrode array is prepared according to the method of Example 3, except that no bias electric field is applied. Specifically, after carbonizing the tantalum wires, while keeping the hydrogen, methane flow rates and the tantalum wire power unchanged, nitrogen gas with a flow rate of 20% of the hydrogen flow rate is introduced, the growth pressure is increased to 3 kPa, and growth starts. After 2 h of growth, it is found that no diamond is deposited on the silicon wafer, indicating that due to the too high aspect ratio, the carbon-containing groups cannot enter the interior of the nanopores without applying a bias voltage.

[0080] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0081] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing patterned diamond, characterized in that, it includes: An insulating substrate is arranged on the surface of the growth substrate. The insulating substrate has a patterned area, and the surface includes an exposed area exposed through the patterned area. The exposed area and the patterned area together constitute the growth area of diamond; Carry out chemical vapor deposition on the growth substrate and apply a bias electric field to generate diamond in the growth area to form the patterned diamond; The thickness of the insulating substrate is 20μm - 500μm, and the aspect ratio of the insulating substrate is (80 - 300):1; The aspect ratio is the ratio of the thickness of the insulating substrate to the width of the narrowest gap in the patterned area; The conditions for applying the bias electric field include: the power supply voltage is 50V - 300V, and the application time is 50 hours - 400 hours; Before arranging the insulating substrate on the surface of the growth substrate, it also includes the step of pre-treating the growth substrate. The surface roughness Ra of the pre-treated substrate is 1μm - 10μm; The chemical vapor deposition is hot filament chemical vapor deposition. Among them, the heating filament is tantalum wire or tungsten wire, the number of heating filaments is 3 - 6, and the single filament power is 900W - 1.5kW; During the process of generating diamond, the conditions for the hot filament chemical vapor deposition include: the growth atmosphere includes hydrogen, methane and inert gas. The flow rate of hydrogen is 200sccm - 500sccm, the flow rate of methane is 3% - 10% of the flow rate of hydrogen, the flow rate of inert gas is 8% - 30% of the flow rate of hydrogen, and the growth pressure is 2.5kPa - 4.5kPa; The pre-treatment includes the following steps: Grind the growth substrate with nano-diamond powder; Put the ground growth substrate into the dispersion liquid of nano-diamond powder and carry out ultrasonic treatment.

2. The preparation method according to claim 1, characterized in that, the growth substrate is a silicon wafer or a molybdenum wafer.

3. The preparation method according to claim 1, characterized in that, the material of the insulating substrate is alumina or quartz, the patterned area is a nano-wire array, a comb-shaped electrode array, a micro-gear array or a micro-spring array, and the thickness of the insulating substrate is 20μm - 200μm.

4. The preparation method according to claim 1, characterized in that, the single filament power is 1.0kW - 1.4kW.

5. The preparation method according to claim 1, characterized in that, the heating filament is a heat-treated heating filament, and the heat treatment is carried out in a mixed gas containing hydrogen and methane. The conditions for the heat treatment include: the heat treatment pressure is 1kPa - 3kPa, the heat treatment time is 10 minutes - 50 minutes, the hydrogen flow rate is 200sccm - 500sccm, and the methane flow rate is 3% - 8% of the hydrogen flow rate.

6. The preparation method according to claim 1, characterized in that, after forming the patterned diamond, it also includes: removing the insulating substrate by an etching process.

7. An article with patterned diamond prepared by the preparation method according to any one of claims 1 - 6.

8. Use of the article with patterned diamond according to claim 7 in a microelectromechanical system, a microsensor or micromachining.

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