CN116639694A - Vibrating diaphragm material, preparation method and acoustic wave sensor - Google Patents
Vibrating diaphragm material, preparation method and acoustic wave sensor Download PDFInfo
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Classifications
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/02—Silicon
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
- C01B32/182—Graphene
- C01B32/184—Preparation
- C01B32/186—Preparation by chemical vapour deposition [CVD]
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H5/00—Measuring propagation velocity of ultrasonic, sonic or infrasonic waves, e.g. of pressure waves
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
- H04R31/003—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor for diaphragms or their outer suspension
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R2231/00—Details of apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor covered by H04R31/00, not provided for in its subgroups
- H04R2231/001—Moulding aspects of diaphragm or surround
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Materials Engineering (AREA)
- Nanotechnology (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Pressure Sensors (AREA)
Abstract
The invention provides a vibrating diaphragm material, a preparation method and an acoustic wave sensor; the vibrating diaphragm material comprises a silicon film and a graphene film; the graphene film grows on the silicon film through Van der Waals force to form a graphene-silicon Van der Waals heterojunction; the thickness of the silicon film is between 200 nanometers and 100 micrometers; the surface roughness of the silicon film is between 0.0001 micrometers and 0.01 micrometers; the number of graphene layers contained in the graphene film is less than or equal to 10.
Description
Technical Field
The invention relates to the field of materials, in particular to a vibrating diaphragm material, a preparation method and an acoustic wave sensor.
Background
Acoustic wave sensors are used in a number of disciplinary applications, including energy sectors (e.g., oil and gas extraction), medical devices (e.g., magnetic resonance and ultrasound imaging), underwater communications, seismic studies (e.g., underwater measurements), non-destructive testing (e.g., large structure monitoring), and military applications (e.g., air, ground and underwater monitoring), among others. The performance requirements of acoustic wave sensors in different fields of science vary widely, but it is generally desirable that acoustic wave sensors have a relatively low minimum detectable pressure, a wide bandwidth (several hertz to tens of thousands of hertz) and a high dynamic range (170 dB of pressure is common), and can be used in environments such as high temperature, high pressure, strong corrosion, strong radiation, etc. where conventional electroacoustic sensors are difficult to operate normally.
The development of acoustic wave sensors has been closely linked to the study of lightweight diaphragm materials. The development of traditional diaphragm materials tends to be bottleneck, and cannot meet the actual demands of the sound wave detection fields of harsh environments such as industry, military and aerospace with high sensitivity, high sound pressure level and wide frequency response.
Silicon is one of the most important semiconductor materials, and has a small thermal expansion coefficient, strong chemical corrosion resistance and good vibration performance without prestressing. At present, a large-area ultrathin silicon film material, generally a silicon film with the thickness of 20-30 mu m, is obtained only through a conventional thinning process. Compared with the traditional thin film materials of metal and polymer, the single crystal silicon is formed by covalent bond combination, has high elastic modulus, is easy to break in plane and delaminate at interface, and cannot bear the damage caused by many conventional manufacturing processes in the process of constructing an acoustic device. Therefore, the low frequency response performance and sensitivity thereof are still greatly limited. If the diaphragm structure of the pickup can be made of a thinner film material with smaller bending stiffness, the sensitivity and the frequency response range of the acoustic wave sensor can be improved.
Disclosure of Invention
In view of the above problems, the present invention aims to overcome the defects of the existing silicon film material that in-plane fracture and interfacial delamination are easy to occur.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the invention provides a vibrating diaphragm material, which comprises a silicon film and a graphene film; the graphene film grows on the silicon film through Van der Waals force to form a graphene-silicon Van der Waals heterojunction;
the thickness of the silicon film is between 200 nanometers and 100 micrometers; the surface roughness of the silicon film is between 0.0001 micrometers and 0.01 micrometers;
the number of graphene layers contained in the graphene film is less than or equal to 10.
The invention also provides a preparation method of the vibrating diaphragm material, which is used for preparing the vibrating diaphragm material and comprises the following steps:
growing a graphene film on the surface of the silicon film to generate a graphene-silicon van der Waals heterojunction;
and reducing the thickness of the silicon film in the graphene-silicon van der Waals heterojunction to a first preset value, and reducing the surface roughness of the silicon film to a second preset value to obtain the vibrating diaphragm material.
In the above technical scheme, the reducing the thickness of the silicon film in the graphene-silicon van der waals heterojunction to a first preset value, and reducing the surface roughness of the silicon film to a second preset value, to obtain the diaphragm material, includes:
determining the etching rate and the etching time according to the original thickness of the silicon film and a first preset value;
determining etching liquid and etching temperature according to the etching rate; wherein the etching liquid contains an active agent with low interfacial tension;
and etching the silicon film in the graphene-silicon van der Waals heterojunction by using an etching solution in the etching time at the determined etching temperature until the thickness of the silicon film is reduced to a first preset value, and reducing the surface roughness of the silicon film to a second preset value to obtain the diaphragm material.
In the above technical scheme, the etching solution is an alkaline solution.
In the technical scheme, the etching solution is KOH solution, and the mass fraction of the KOH solution is between 1% and 80%.
In the technical scheme, the etching temperature is between 20 ℃ and 100 ℃.
In the above technical scheme, the step of growing a graphene film on the surface of a silicon film to generate a graphene-silicon van der waals heterojunction comprises the following steps:
placing the silicon film in a high-temperature tube furnace, wherein the temperature in a reaction cavity of the high-temperature tube furnace is set to 300-1500 ℃;
vacuumizing the reaction cavity so that the atmospheric pressure in the reaction furnace is within a preset range;
introducing mixed gas containing protective gas and reducing gas into the reaction cavity, and introducing carbon source steam into the reaction cavity after the gas flow of the mixed gas is stable;
and after a preset time period, closing the carbon source steam and continuing to introduce the mixed steam, and closing the mixed gas after the temperature in the reaction furnace reaches the room temperature.
The invention also provides an acoustic wave sensor, which adopts the vibrating diaphragm material in the technical scheme.
Due to the adoption of the technical scheme, the invention has the following advantages:
the diaphragm material provided by the invention is characterized in that a graphene film is directly grown on the surface of silicon base to form a graphene-silicon van der Waals heterojunction. Under the multi-stage interaction of Van der Waals force, covalent bond and the like at the interface of the two, the stress is effectively dispersed and transferred, and the sound transmission speed and the tension bearing level of the vibrating diaphragm are improved. The problem that the reliable suspension distance of the general graphene thin diaphragm material is not more than 10 mu m is solved, the mechanical property of the material is greatly provided, and the preparation and application of the large-size diaphragm material can be realized. Meanwhile, by means of chemical stability of graphene in severe environments such as strong acid resistance, strong alkali resistance and the like, a submicron silicon film thinning process is developed, and high-quality response of the diaphragm material in infrasonic wave, audible sound and ultrasonic wave bands is achieved through double optimization of the diaphragm material and structural parameters, so that a technical foundation is provided for preparing a high-sensitivity broadband response acoustic wave sensing device.
In addition, because the graphene is adopted to dope the silicon, the overall conductivity is improved, and therefore, when the silicon film containing the graphene film is used as a vibrating diaphragm material, an electrode is not required to be additionally evaporated, and the preparation complexity is reduced.
Drawings
In order to more clearly illustrate the invention or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a vibrating diaphragm material of the present invention;
FIG. 2 is a flow chart of a method of preparing a diaphragm material of the present invention;
FIG. 3 (a) is a Raman spectrum of silicon-based graphene of different growth times;
fig. 3 (b) is a graph of transmittance spectrum and corresponding resistance change of silicon-based graphene with different growth times;
fig. 4 (a) is a physical diagram of graphene grown on the surface of a silicon film;
FIG. 4 (b) is a low-power TEM image of graphene grown on the surface of a silicon film;
FIG. 4 (c) is a high-power TEM image of graphene grown on the surface of a silicon film; .
FIG. 5 is a physical diagram of a thinned graphene-silicon van der Waals heterojunction diaphragm material;
fig. 6 is a graph of the frequency response of an acoustic wave sensor employing the diaphragm material of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the prior art, a silicon film is one implementation of a diaphragm material in an acoustic wave sensor. However, the silicon film in the prior art is formed by bonding monocrystalline silicon through covalent bonds, has very high Young's modulus, is easy to generate in-plane fracture and interfacial delamination, and cannot bear the damage caused by a plurality of conventional manufacturing processes in the process of constructing an acoustic device. Therefore, the low-frequency response performance and sensitivity of the acoustic sensor manufactured by using the silicon film in the prior art as the diaphragm material are greatly limited.
Based on the above-mentioned problems in the prior art, the present invention provides a vibrating diaphragm material, and fig. 1 is a schematic structural diagram of the vibrating diaphragm material of the present invention. As shown in fig. 1, the diaphragm material includes a silicon film and a graphene film grown on the silicon film by van der waals force, forming a graphene-silicon van der waals heterojunction.
The thickness of the silicon film is between 200 nanometers and 100 micrometers; the surface roughness of the silicon film is between 0.0001 and 0.01 micrometers.
The number of graphene layers contained in the graphene film is less than or equal to 10.
In the diaphragm material, a graphene film and a silicon film form a graphene-silicon van der Waals heterojunction through van der Waals force. The Van der Waals heterojunction forms the graphene film and the silicon film into a whole, so that the ultra-thin performance, the excellent mechanical performance and the extreme flexibility of the graphene can be utilized, the conductivity, the sound propagation speed, the Young modulus, the loss factor (internal damping) and other physical indexes of the silicon film are improved, the sensitivity and the frequency response range of the whole diaphragm material are improved, and lower distortion is obtained. In addition, because the graphene is adopted to dope the silicon, the overall conductivity is improved, and therefore, when the silicon film containing the graphene film is used as a vibrating diaphragm material, an electrode is not required to be additionally evaporated, and the preparation complexity is reduced.
The invention also provides a preparation method of the vibrating diaphragm material, fig. 2 is a flow chart of the preparation method of the vibrating diaphragm material, and as shown in fig. 2, the preparation method of the vibrating diaphragm material comprises the following steps:
and step 1, growing a graphene film on the surface of the silicon film to generate a graphene-silicon van der Waals heterojunction.
In this embodiment, a chemical vapor deposition method is used to grow a graphene film on the surface of a silicon film. Specifically, the method comprises the following steps:
placing the silicon film in a high-temperature tube furnace, wherein the temperature in a reaction cavity of the high-temperature tube furnace is set to 300-1500 ℃;
vacuumizing the reaction cavity so that the atmospheric pressure in the reaction furnace is within a preset range;
introducing mixed gas containing protective gas and reducing gas into the reaction cavity, and introducing carbon source steam into the reaction cavity after the gas flow of the mixed gas is stable;
and after a preset time period, closing the carbon source steam and continuing to introduce the mixed steam, and closing the mixed gas after the temperature in the reaction furnace reaches the room temperature.
In this embodiment, the preset range of the atmospheric pressure in the reaction furnace may be between 1Pa and 100 Pa.
In this embodiment, the protective gas introduced into the reaction chamber may be argon, and the reducing gas may be hydrogen. The carbon source vapor introduced into the reaction chamber may be at least one of gaseous (methane, ethylene, acetylene), solid (polyaniline, polystyrene, etc.), and liquid (toluene, benzoic acid, chlorobenzene, ethanol, acetonitrile, etc.) carbon sources.
When the silicon film reacts in the high-temperature tube furnace, the reaction temperature, various gas flows and reaction time can be adjusted according to the process requirements, and the following principles are specifically followed:
(1) The higher the reaction temperature, the faster the graphene grows, and the larger the domain area;
(2) The higher the proportion of the carbon source gas is, the faster the graphene grows;
(3) The longer the growth time, the thicker the number of graphene layers.
In this example, the reaction temperature when the silicon film is reacted in the high temperature tube furnace is 1050 degrees celsius; the gas flow rate is Ar/H 2 1000/1000sccm; the reaction time was 30min.
Fig. 3 (a) is a raman spectrum of silicon-based graphene of different growth times, and fig. 3 (b) is a transmittance spectrum and a corresponding resistance change pattern of silicon-based graphene of different growth times. Fig. 3 (a) shows that the 2D peak in fig. 3 (a) gradually widens with time, which illustrates that the growth time of graphene increases and the number of graphene layers increases, namely: the number of layers of graphene can be controlled by controlling the growth time of graphene. The transmittance change and the resistance change shown in fig. 3 (b) can also indicate that the number of graphene layers increases as the growth time of graphene increases.
Through the reaction, the silicon film and the graphene film are combined together through Van der Waals force to form a graphene-silicon Van der Waals heterojunction.
And step 2, reducing the thickness of the silicon film in the graphene-silicon van der Waals heterojunction to a first preset value, and reducing the surface roughness of the silicon film to a second preset value to obtain the vibrating diaphragm material.
In general, a silicon film obtained on the market has a thickness of the order of several hundred micrometers, and if the silicon film is applied to an acoustic sensor as a diaphragm material, the thickness thereof is required to be 100 micrometers or less. Therefore, it is necessary to reduce the thickness of the silicon film on the basis of the graphene-silicon van der waals heterojunction obtained in step 1.
In the prior art, there are various techniques for reducing the thickness of silicon film, such as grinding, polishing, dry polishing, electrochemical etching, wet etching, plasma-assisted chemical etching, atmospheric pressure plasma etching, and the like. However, these prior arts cannot solve the problem of how to precisely control the silicon film thickness when reducing the silicon film thickness. In addition, the surface roughness of the silicon film directly affects the response sensitivity of the diaphragm material. Therefore, the surface roughness of the silicon film is reduced while the silicon film is etched.
In this embodiment, the steps specifically include:
determining the etching rate and the etching time according to the original thickness of the silicon film and a first preset value;
determining etching liquid and etching temperature according to the etching rate; wherein the etching liquid contains an active agent with low interfacial tension;
and etching the silicon film in the graphene-silicon van der Waals heterojunction by using an etching solution in the etching time at the determined etching temperature until the thickness of the silicon film is reduced to a first preset value, and reducing the surface roughness of the silicon film to a second preset value to obtain the diaphragm material.
In this embodiment, the first preset value is a target thickness of the silicon film, e.g., the first preset value is a value between 200 nm and 100 μm; the second preset value is a target value of the surface roughness of the silicon film, for example, the second preset value is a value between 0.0001 micrometers and 0.01 micrometers.
The etching solution is an aqueous solution of alkali metal hydroxide, and in this embodiment, the etching solution is a KOH solution, and the mass fraction of the KOH solution is between 1% and 80%. In other embodiments, the composition of the etching solution may also vary, such as by using an aqueous alkaline solution having a pH of 12 or more containing an alkali metal hydroxide, a hydroxylamine and an inorganic carbonic acid compound. The etching liquid may also be an acidic solution such as a mixed liquid in which nitric acid in an amount of more than 0vol% and not more than 80vol%, hydrofluoric acid in an amount of more than 0vol% and not more than 20vol%, and acetic acid in an amount of more than 0vol% and not more than 50vol% are mixed together.
The etching temperature can be controlled between 20 ℃ and 100 ℃.
The rate at which the etching liquid etches the silicon film is also related to the etching temperature and the etching liquid concentration. Within the foregoing range, the higher the etching temperature, the higher the etching rate; the higher the etching liquid concentration, the higher the etching rate.
For example, the etching rate of the silicon film can be controlled to 1.01 μm/min by using 40wt% KOH etching solution, the etching temperature being controlled to 80 ℃. Further, if the original thickness of the silicon film is 90 micrometers, the etching time of the silicon film by using the etching solution is controlled to be 10 minutes, and the silicon film with the thickness of about 80 micrometers can be obtained.
In this embodiment, the tension of the silicon surface is reduced by adding an active agent with low interfacial tension into the etching solution, so that the wettability of the silicon surface is improved, and the surface roughness of the silicon film is reduced. The low interfacial tension agent may be FM-31 low interfacial tension agent (nonionic) or FC-116 low interfacial tension agent (anionic) of Hangzhou ren fir technology Co.
According to the invention, a high-quality graphene film is directly grown on the surface of the silicon substrate by adopting a chemical vapor deposition method, so that a graphene-silicon van der Waals heterojunction is formed. Under the multi-stage interaction of Van der Waals force, covalent bond and the like at the interface of the two, the stress is effectively dispersed and transferred, and the sound transmission speed and the tension bearing level of the vibrating diaphragm are improved. The problem that the reliable suspension distance of the general graphene thin diaphragm material is not more than 10 mu m is solved, the mechanical property of the material is greatly provided, and the preparation and application of the large-size diaphragm material can be realized. Meanwhile, by means of chemical stability of graphene in severe environments such as strong acid resistance, strong alkali resistance and the like, a submicron silicon film thinning process is developed, and high-quality response of the diaphragm material in infrasonic wave, audible sound and ultrasonic wave bands is achieved through double optimization of the diaphragm material and structural parameters, so that a technical foundation is provided for preparing a high-sensitivity broadband response acoustic wave sensing device.
The invention also provides an acoustic wave sensor, which adopts the vibrating diaphragm material.
The vibrating diaphragm material provided by the invention is a graphene-silicon van der Waals heterojunction, and can improve various physical indexes such as conductivity, sound propagation speed, young modulus, loss factor (internal damping) and the like of a silicon film by utilizing the ultrathin property, excellent mechanical property and extreme flexibility of graphene, so that the whole vibrating diaphragm material has higher sensitivity, frequency response range and lower distortion, and further the acoustic wave sensor utilizing the vibrating diaphragm material has higher sensitivity, frequency response range and lower distortion.
The present invention will be described in detail below with reference to the accompanying drawings and examples.
Example 1
And sequentially placing the silicon wafer in cyclohexane, ethanol and deionized water for ultrasonic cleaning for 10 minutes, and drying by using nitrogen to finish cleaning the silicon wafer. Placing the cleaned silicon wafer into a 1100 ℃ high-temperature tube furnace, pumping the atmospheric pressure in the reaction cavity to 10Pa by using an oil-free vortex vacuum pump, and introducing 1000/1000sccm Ar/H 2 After the air flow is stable, a methane gas valve is opened, and the flow is controlled to be 1000sccm through methane gas, so that the methane gas valve is openedThe alkane vapor is quickly cracked into active carbon species after entering the reaction cavity, and a large amount of active carbon species are adsorbed on the surface of the silicon wafer and migrate and collide on the surface, so that the nucleation and growth of microcrystalline graphite are realized. The graphene growth process is set to 120 minutes, a methane valve is rapidly closed after the growth is finished, and Ar/H is carried out 2 Setting to 300/300sccm, and starting the cooling process. When the temperature in the reaction cavity is reduced to room temperature, closing Ar/H 2 And opening the bin to take out the sample.
Preparing 40% KOH etching solution by mass, adding 3% FM-31 low interfacial tension active agent (nonionic) by Hangzhou Renzea science and technology Co., ltd.) by mass, and controlling the etching temperature at 80 ℃. And soaking the prepared silicon-based graphene material in a reaction tank with etching liquid for 6 minutes, taking out, washing with deionized water, and drying for characterization.
Analysis of experimental results: the graphene on the silicon surface is characterized by a transmission electron microscope, fig. 4 (a) is a physical image of the graphene growing on the silicon film surface, fig. 4 (b) is a low-power TEM image of the graphene growing on the silicon film surface, and fig. 4 (c) is a high-power TEM image of the graphene growing on the silicon film surface. As can be seen from these figures, the silicon film surface realizes the growth of graphene.
Fig. 5 is a schematic view of a thinned graphene-silicon van der waals heterojunction diaphragm material, from which it can be seen that an ultra-thin and ultra-flexible diaphragm material is obtained by the above method, and further the surface roughness Ra thereof is 0.001 μm by SEM test.
Based on the existing 1/4 inch acoustic wave sensor on the market, the original vibrating diaphragm is replaced by the graphene-silicon van der Waals heterojunction vibrating diaphragm, and the frequency response curve of the vibrating diaphragm is tested through an acoustic test platform, as shown in fig. 6, the frequency response range of the vibrating diaphragm can reach 10 Hz-100 kHz, the frequency response curve is flat, and the sensitivity is-30 dB.
Example 2
And sequentially placing the silicon wafer in cyclohexane, ethanol and deionized water for ultrasonic cleaning for 10 minutes, and drying by using nitrogen to finish cleaning the silicon wafer. Placing the cleaned silicon wafer into a high-temperature tube furnace at 1500 ℃, and utilizing an oil-free vortex vacuum pump to ensure the atmospheric pressure in a reaction cavityPumping to 1Pa, introducing 1000/1000sccm Ar/H 2 And after the air flow is stable, opening a polyaniline gas valve, controlling the flow to 1000sccm through polyaniline gas, and rapidly cracking polyaniline vapor into active carbon species after entering a reaction cavity, wherein a large amount of active carbon species are adsorbed on the surface of a silicon wafer and migrate and collide on the surface, so that the nucleation and growth of microcrystalline graphite are realized. The graphene growth process is set to 30 minutes, the polyaniline gas valve is rapidly closed after the growth is finished, and Ar/H is carried out 2 Setting to 300/300sccm, and starting the cooling process. When the temperature in the reaction cavity is reduced to room temperature, closing Ar/H 2 And opening the bin to take out the sample.
Preparing KOH etching solution with mass fraction of 80%, adding FC-116 low interfacial tension active agent (anion type) with mass fraction of 3% of Hangzhou Renzea science and technology Co., ltd, and controlling etching temperature at 20deg.C. And soaking the prepared silicon-based graphene material in a reaction tank with etching liquid for 6 minutes, taking out, washing with deionized water, and drying for characterization.
Example 3
And sequentially placing the silicon wafer in cyclohexane, ethanol and deionized water for ultrasonic cleaning for 10 minutes, and drying by using nitrogen to finish cleaning the silicon wafer. Placing the cleaned silicon wafer into a high-temperature tube furnace at 300 ℃, pumping the atmospheric pressure in a reaction cavity to 100Pa by using an oil-free vortex vacuum pump, and introducing 1000/1000sccm Ar/H 2 And after the air flow is stable, opening an ethanol gas valve, introducing ethanol gas, controlling the flow to be 1000sccm, and rapidly cracking the ethanol gas into active carbon species after the ethanol gas enters a reaction cavity, wherein a large amount of active carbon species are adsorbed on the surface of a silicon wafer and migrate and collide on the surface, so that the nucleation and growth of microcrystalline graphite are realized. The graphene growth process is set to 30 minutes, an ethanol gas valve is rapidly closed after growth is finished, and Ar/H is carried out 2 Setting to 300/300sccm, and starting the cooling process. When the temperature in the reaction cavity is reduced to room temperature, closing Ar/H 2 And opening the bin to take out the sample.
Preparing KOH etching solution with the mass fraction of 1%, adding FC-116 low interfacial tension active agent (anion type) with the mass fraction of 3% of Hangzhou kernel fir science and technology Co., ltd, and controlling the etching temperature at 100 ℃. And soaking the prepared silicon-based graphene material in a reaction tank with etching liquid for 30 minutes, taking out, washing with deionized water, and drying for characterization.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (8)
1. The vibrating diaphragm material is characterized by comprising a silicon film and a graphene film; the graphene film grows on the silicon film through Van der Waals force to form a graphene-silicon Van der Waals heterojunction;
the thickness of the silicon film is between 200 nanometers and 100 micrometers; the surface roughness of the silicon film is between 0.0001 micrometers and 0.01 micrometers;
the number of graphene layers contained in the graphene film is less than or equal to 10.
2. A method for preparing a diaphragm material, for preparing the diaphragm material of claim 1, comprising:
growing a graphene film on the surface of the silicon film to generate a graphene-silicon van der Waals heterojunction;
and reducing the thickness of the silicon film in the graphene-silicon van der Waals heterojunction to a first preset value, and reducing the surface roughness of the silicon film to a second preset value to obtain the vibrating diaphragm material.
3. The method for preparing a diaphragm material according to claim 2, wherein the reducing the thickness of the silicon film in the graphene-silicon van der waals heterojunction to a first preset value and the reducing the surface roughness of the silicon film to a second preset value, to obtain the diaphragm material, comprises:
determining the etching rate and the etching time according to the original thickness of the silicon film and a first preset value;
determining etching liquid and etching temperature according to the etching rate; wherein the etching liquid contains an active agent with low interfacial tension;
and etching the silicon film in the graphene-silicon van der Waals heterojunction by using an etching solution in the etching time at the determined etching temperature until the thickness of the silicon film is reduced to a first preset value, and reducing the surface roughness of the silicon film to a second preset value to obtain the diaphragm material.
4. A method of producing a diaphragm material according to claim 3, wherein the etching liquid is an aqueous solution of an alkali metal hydroxide.
5. The method for preparing a diaphragm material according to claim 4, wherein the etching solution is a KOH solution, and the mass fraction of the KOH solution is between 1% and 80%.
6. A method of producing a diaphragm material according to claim 3, wherein the etching temperature is between 20 ℃ and 100 ℃.
7. The method for preparing a diaphragm material according to claim 2, wherein the growing a graphene film on a silicon film surface to form a graphene-silicon van der waals heterojunction comprises:
placing the silicon film in a high-temperature tube furnace, wherein the temperature in a reaction cavity of the high-temperature tube furnace is set to 300-1500 ℃;
vacuumizing the reaction cavity so that the atmospheric pressure in the reaction furnace is within a preset range;
introducing mixed gas containing protective gas and reducing gas into the reaction cavity, and introducing carbon source steam into the reaction cavity after the gas flow of the mixed gas is stable;
and after a preset time period, closing the carbon source steam and continuing to introduce the mixed steam, and closing the mixed gas after the temperature in the reaction furnace reaches the room temperature.
8. An acoustic wave sensor, wherein the acoustic wave sensor employs the diaphragm material of claim 1.
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| CN117381147B (en) * | 2023-12-13 | 2024-03-19 | 昆山海菲曼科技集团股份有限公司 | Precise laser processing device and laser processing method for acoustic thin film |
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