Mechanical resonator, forced resonance device and manufacturing method and applications

Abstract

The application provides a mechanical resonator, a forced resonance device and a manufacturing method and application, and belongs to the technical field of electronic components.The mechanical resonator provided by the application comprises an insulating substrate with a through hole in a partial region, the substrate is provided with a conductive film above the substrate, the substrate is provided with a chamber below the substrate, there is a pressure difference between the inside and outside of the chamber, the conductive film is deformed under the action of the pressure difference; the chamber is provided with a liquid medium, and the liquid medium is in contact with the conductive film through the through hole on the substrate.The mechanical resonator and the forced resonance device provided by the application can generate measurable periodic mechanical vibration under an alternating voltage of 10 mV, and through adjusting the amplitude and frequency of the alternating signal and the gas pressure in the chamber, a multi-dimensional adjustable vibration response can be realized, the excitation efficiency is greatly improved, and the system energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electronic components, and particularly relates to a mechanical resonator, a forced resonance device, a manufacturing method and an application. BACKGROUND

[0002] Micro / Nano Electro Mechanical System (MEMS / NEMS) is a multi-functional micro system technology that integrates micron or even nanometer scale mechanical structures, sensing elements, actuators, electronic circuits and signal processing units on the same chip. It can sense (pressure, acceleration, temperature, chemical composition, etc.) and drive (force, displacement, flow, etc.) through micro-nano processing technology (such as photolithography, etching, thin film deposition, etc.) on silicon or other material substrates, thereby realizing the advantages of high integration, low power consumption, high sensitivity and mass production.

[0003] Mechanical resonator is one of the most important basic components in micro-nano mechanical system, and its core is a micro structure that can produce stable mechanical oscillation at a specific frequency, such as beam, disc, ring or thin film structure. Mechanical resonator realizes high sensitive response to external disturbance through its inherent vibration mode, and thus plays a key role in many fields: on the one hand, they are widely used as frequency reference and filtering unit in clock source and wireless communication system; on the other hand, with the ability to accurately perceive small mass, force, pressure and acceleration, mechanical resonator constitutes the core of many types of sensors; in addition, relying on piezoelectric or capacitive coupling mechanism, they can also realize the conversion between mechanical energy and electrical energy for energy harvesting and signal modulation. The position of mechanical resonator in micro-nano mechanical system is particularly prominent: on the one hand, its micron / nanometer size enables mechanical resonator to be compatible with integrated circuits, realizing chip-level low-cost packaging; on the other hand, its high quality factor and tunable frequency characteristics provide the system with precise frequency stability and selectivity.

[0004] The commonly used mechanical resonators can be divided into three types according to the working mode: "bending vibration" type resonators, "acoustic wave vibration" type resonators, and "torsional / extensional vibration" type resonators. Among them, the cantilever resonator is a typical "bending vibration" type resonator, and its excitation methods mainly include piezoelectric excitation and photothermal excitation. The cantilever resonator has the advantages of simple structure, easy micro-nano processing, easy adjustment of working frequency, high sensitivity to external disturbances, etc., and is suitable for chip-level sensors, which can detect pico-newton level forces (such as AFM) and femto-level mass changes (such as gas sensors). The double-clamped bridge resonator is another typical "bending vibration" type resonator, and its excitation methods mainly include piezoelectric excitation and electrostatic excitation. The double-clamped bridge resonator has a compact structure and a modular design, which is convenient for integration into complex systems, such as micro-packaging of MEMS switches. Compared with the cantilever resonator, the double-clamped bridge resonator has higher system stiffness due to its symmetric clamping design, which reduces the disturbance of lateral stress, thus having better frequency stability and higher quality factor, and is suitable for high-precision positioning or fixed scenarios (such as robot clamps). Acoustic wave resonators include bulk acoustic wave resonators (BAW) and surface acoustic wave resonators (SAW). The acoustic wave of BAW propagates in the bulk of the piezoelectric material to form standing wave resonance, and common structures include film bulk acoustic resonator (FBAR) and solidly mounted resonator (SMR). The acoustic wave of SAW propagates along the surface of the piezoelectric material and is excited and received by the interdigital transducer (IDT). Both of them are excited by piezoelectric excitation. However, compared with SAW resonators, BAW resonators have energy distributed in the material body, which is suitable for high-frequency, high-power, and high-stability devices, and are widely used in filtering and frequency control in radio frequency communication. SAW resonators have the advantages of low cost and easy integration due to the concentration of energy on the surface, mature process, and easy miniaturization, and are commonly used in wireless communication filtering, radio frequency identification (RFID), and wireless sensors. As can be seen from the above relatively mature and widely used resonators, the existing mechanical resonators are mainly excited by piezoelectric and electrostatic excitation, and existing practices and research have shown that piezoelectric excitation is the "general preferred" option, which is suitable for various structures and takes into account efficiency and integration. Electrostatic excitation is more suitable for "high-precision, small-amplitude" scenarios (such as MEMS switches). In addition, electrothermal, photothermal, electromagnetic, and other methods are also applied in specific scenarios to meet the driving requirements of different structures, frequencies, and environmental conditions.For example, electrothermal excitation uses Joule heating to initiate thermal elastic vibration, has the advantages of simple structure and no need for additional materials, and is often used for low-frequency driving and modulation of micro-nano beams and thin film resonators; photo-thermal excitation relies on periodic light to generate local temperature fluctuations to drive structural vibration, has the characteristics of non-contact, fast response and suitability for ultra-thin film devices (such as graphene, two-dimensional materials), and is often used for high-sensitivity sensing and nanomechanics research; electromagnetic excitation is based on the Lorentz force of current in a magnetic field to drive, and has the advantages of large driving force and wide frequency response, and is suitable for micro-speakers, inertial sensors and MEMS devices that require strong driving force. With the advantages of micro-nano structure, flexible excitation mode and wide application scenarios, mechanical resonators have become a key basic component for realizing high-precision detection, stable frequency control and multi-functional signal processing, and have irreplaceable important significance in the fields of information technology, sensing technology and intelligent systems.

[0005] Although the existing resonators have been applied in gas phase or vacuum environment, they all have significant limitations when applied in liquid environment. The reason is that the existing structure and excitation method are designed based on gas phase / vacuum environment, and there are inherent conflicts between the characteristics of the existing structure and excitation method and the physical and chemical characteristics (conductivity, thermal conductivity, viscosity, etc.) of liquid environment. Liquid has the characteristics of conductivity (or ionic conductivity), high thermal conductivity, high viscosity, high dielectric constant, etc., and the working principle of the existing excitation method relies on the physical properties of gas phase environment (such as insulation, low thermal conductivity, low damping), so the compatibility is poor. This directly leads to the conflict between the "small size, integration requirement" of the existing mechanical resonator structure and the "complexity of liquid medium". On the one hand, the processing precision requirement of the microstructure and the interference of the liquid medium are reflected. The advantages of structures such as double-sided clamping bridge and cantilever beam are "small size" (usually microns or even nanometers), which need to rely on micro-nano processing technology (such as photolithography, etching, precise assembly) to realize. But the complex liquid medium (such as electrolyte containing ions, corrosive industrial liquid, high-viscosity biological fluid) puts higher requirements on the processing process: if it needs to be used in liquid after processing, the structure surface needs to have corrosion resistance and anti-pollution ability (such as avoiding the attachment of ions in the liquid), which requires additional surface modification steps (such as plating, chemical passivation) during processing, increasing the process complexity. In addition, the mechanical stability of the microstructure is poor (such as the deflection of the cantilever beam is easily affected by the processing error), and the viscosity of the liquid will amplify the vibration interference in the processing process (such as the liquid flow during etching may cause structure deformation), which requires higher precision of the tool clamp, increasing the processing difficulty. On the other hand, the contradiction between integration requirement and liquid sealing and adaptability is reflected. These structures need to be "easily integrated" into the equipment in liquid environment (such as sensors, microfluidic chips), but the "liquid sealing" problem needs to be solved during integration: if the liquid may seep into the gap and cause structural failure (such as the fixed end of the cantilever beam is corroded), the flatness and tolerance of the connection surface need to be accurately controlled during processing, or special sealing materials (such as elastomers) need to be used, increasing the process cost; the flowability and pressure change of complex liquid may generate additional load on the structure (such as the impact force of high-viscosity liquid flowing through a thin plate), which needs to be pre-designed during processing (such as thickening, optimizing the shape), but this will sacrifice the advantage of "small size", forming a dilemma in design and processing. This also means that the optimization for liquid environment needs to start from "adapting to the characteristics of liquid", rather than directly using the technology of gas phase environment.

[0006] In summary, if the existing mechanical resonator is directly applied to liquid environment, it will put higher requirements on its processing, increase the processing difficulty, and also inevitably face problems such as high energy consumption and poor chemical stability in application, directly restricting the performance improvement and scene expansion of the existing mechanical resonator. Therefore, it is urgent to develop a new type of mechanical resonator to break through the technical bottleneck of the existing technology. SUMMARY

[0007] Problem to be solved

[0008] Based on the above, one of the purposes of the present application is to provide a new mechanical resonator, while providing the preparation of the mechanical resonator, which is simple in structure, while having the adaptation characteristics of liquid environment application, and is easy to process.

[0009] Technical solution

[0010] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0011] The first aspect of the present application provides a mechanical resonator, which comprises: a substrate, the substrate is an insulating substrate, and the substrate has at least a partial area with a through hole;

[0012] A conductive film located above the substrate;

[0013] A chamber located below the substrate, the substrate cooperates with the conductive film to form a seal for the chamber, there is a pressure difference between the inside and outside of the chamber, the conductive film is deformed under the action of the pressure difference; inside the chamber, there is a liquid medium, the liquid medium is in contact with the conductive film located above the substrate through the through hole on the substrate;

[0014] A first electrode in contact with the conductive film;

[0015] A second electrode in contact with the liquid medium.

[0016] As a preferred embodiment of any of the first aspect of the present application, the pressure difference between the inside and outside of the chamber is 10-140kPa;

[0017] Further, the pressure difference between the inside and outside of the microcavity can be any value taken from any of the following ranges: 10-140 kPa, 10-130 kPa, 10-120 kPa, 10-110 kPa, 10-100 kPa, 10-90 kPa, 10-80 kPa, 10-70 kPa, 10-60 kPa, 10-50 kPa, 10-40 kPa, 10-30 kPa, 10-20 kPa, 20-100 kPa, 30-100 kPa, 40-100 kPa, 50-100 kPa, 60-100 kPa, 70-100 kPa, 80-100 kPa, 90-100 kPa, 20-120 kPa, 30-120 kPa, 40-120 kPa, 50-120 kPa, 60-120 kPa, 70-120 kPa, 80-120 kPa, 90-120 kPa, 100-120 kPa, 20-140 kPa, 30-140 kPa, 40-140 kPa, 50-140 kPa, 60-140 kPa, 70-140 kPa, 80-140 kPa, 90-140 kPa, 100-140 kPa, 120-140 kPa.

[0018] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the liquid medium is located in the direction close to the substrate, and the air cavity is located in the direction away from the substrate.

[0019] The liquid medium in the cavity is in contact with the conductive film above the substrate through the through-hole on the substrate.

[0020] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the conductive film comprises a resonance region and a connecting region.

[0021] The resonance region is close to the geometric center of the conductive film, and the connecting region is close to the geometric edge of the conductive film.

[0022] The resonance region substantially corresponds to the position of the region on the substrate having the through-hole.

[0023] Compared with the connecting region of the conductive film, the resonance region is convex in the direction away from the substrate.

[0024] Further, the liquid medium in the cavity is in contact with the resonance region through the through-hole.

[0025] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the first electrode is arranged above the substrate and in contact with the conductive film.

[0026] The second electrode is arranged below the substrate and in contact with the liquid medium.

[0027] Preferably, the first electrode is in contact with the connection region of the conductive film.

[0028] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the chamber wall of the chamber is provided with an air port and a sealing member.

[0029] As described herein, the air port can be used to inflate or deflate the air cavity to form a pressure difference inside and outside the chamber.

[0030] The sealing member can seal the air port.

[0031] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the conductive film has any one or more of the following conditions:

[0032] (I) The thickness is 0.3 nm to 15 nm; further, the thickness can be any value taken from any of the following numerical ranges: 0.3-13 nm, 0.3-11 nm, 0.3-10 nm, 0.3-8 nm, 0.3-6 nm, 0.3-4 nm, 0.33-1 nm.

[0033] (II) The contact angle is less than 90° in the unpowered state; further, the contact angle can be any value taken from any of the following numerical ranges: 10-80°, 20-70°, 30-60°.

[0034] (III) The elastic modulus is 10-1500 N / m; further, the elastic modulus can be any value taken from any of the following numerical ranges: 50-1400 N / m, 80-1300 N / m, 100-1200 N / m, 100-1000 N / m, 100-800 N / m, 100-700 N / m, 100-600 N / m, 100-500 N / m.

[0035] (IV) The pre-tension is 0.1-1.0 N / m; further, the pre-tension can be any value taken from any of the following numerical ranges: 0.1-0.8 N / m, 0.1-0.7 N / m, 0.1-0.6 N / m, 0.1-0.5 N / m.

[0036] (V) The conductive film material includes but is not limited to graphene, molybdenum disulfide, and nanometer metal (metal type is inert metal) film.

[0037] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the substrate has any one or more of the following conditions:

[0038] (I) The thickness is 300-1000 nm; further, the thickness can be any value taken from any of the following numerical ranges: 300-900 nm, 300-800 nm, 300-700 nm, 300-600 nm, 300-500 nm;

[0039] (II) The resistivity is not lower than 1×10 10 Ω·m; further, the resistivity can be any value taken from any of the following numerical ranges: 1×10 11 Ω·m-1×10 20 Ω·m, 1×10 12 Ω·m-1×10 20 Ω·m, 1×10 13 Ω·m-1×10 20 Ω·m, 1×10 14 -1×10 20 Ω·m;

[0040] (III) The material of the substrate includes but is not limited to one or both of silicon nitride and silicon oxide.

[0041] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the liquid medium has any one or more of the following conditions:

[0042] (I) The liquid medium includes but is not limited to any one, two or more of water and electrolyte;

[0043] (II) The ion concentration of the liquid medium is 0-10 mol / L; further, the ion concentration can be any value taken from any of the following numerical ranges: 0.1-10 mol / L, 0.1-8 mol / L, 0.1-6 mol / L, 0.1-4 mol / L, 0.1-2 mol / L, 0.1-1 mol / L, 1-10 mol / L, 3-10 mol / L, 5-10 mol / L, 7-10 mol / L, 9-10 mol / L;

[0044] (III) The liquid medium is preferably an electrolyte solution, and the electrolyte solution contains ion types including but not limited to one or more of potassium ion, sodium ion, lithium ion, hydrogen ion, chloride ion, nitrate ion, and sulfate ion;

[0045] (VI) The electrolyte solution includes but is not limited to acid solution, alkali solution, and salt solution.

[0046] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the material of the electrode includes but is not limited to titanium, gold, platinum, nickel.

[0047] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the gas type includes but is not limited to air, nitrogen, argon.

[0048] As a preferred embodiment of any of the technical solutions of the first aspect of the present application, the material of the chamber wall of the chamber includes but is not limited to aluminum, stainless steel, polytetrafluoroethylene.

[0049] The second aspect of the present application provides a forced resonance device, which includes the mechanical resonator of any of the technical solutions of the first aspect of the present application, and an excitation voltage (generally alternating current);

[0050] The excitation voltage is electrically connected with the electrode of the mechanical resonator.

[0051] The third aspect of the present application provides a manufacturing method of a mechanical resonator, which includes the following steps:

[0052] (1) preparing a substrate, the substrate is an insulating substrate, and the substrate has at least a partial area with a through hole;

[0053] The first electrode and the second electrode are respectively arranged on the side surface above the substrate and the side surface below the substrate;

[0054] (2) fixing a conductive film to the side surface above the substrate, and ensuring that the conductive film is in effective contact with the first electrode;

[0055] (3) preparing a microcavity with a chamber, the chamber of the microcavity is a semi-closed microcavity with an opening on one side;

[0056] The chamber wall of the microcavity is provided with a gas port and a sealing member, and the gas port can be used to charge or exhaust the chamber;

[0057] The sealing member can seal the gas port;

[0058] (4) adding a liquid medium into the chamber of the microcavity through the opening on one side;

[0059] (5) mounting the substrate to the opening side of the microcavity, so as to close the chamber of the microcavity;

[0060] (6) charging or exhausting the closed chamber through the gas port of the microcavity, so as to form a pressure difference between the inside and outside of the chamber of the microcavity.

[0061] As a preferred embodiment of any of the third aspect of the present application, in step (1), an electron beam evaporation technique is used to form the first electrode and the second electrode on the side above and the side below of the substrate, respectively.

[0062] As a preferred embodiment of any of the third aspect of the present application, in step (2), a dry transfer technique is used to transfer the conductive film to the side above of the substrate and make it contact with the first electrode.

[0063] As a preferred embodiment of any of the third aspect of the present application, in step (2), PMMA (polymethyl methacrylate) is used to assist the dry transfer.

[0064] After the transfer is completed, the PMMA is removed by soaking.

[0065] As a preferred embodiment of any of the third aspect of the present application, in step (2), after the soaking is completed, a carbon dioxide supercritical drying instrument is used to dry the sample. The foregoing can reduce the structural damage caused by the surface tension of the liquid during the drying process.

[0066] As a preferred embodiment of any of the third aspect of the present application, in step (6), after the inflation or deflation is completed, the liquid medium in the chamber contacts the conductive film through the through hole.

[0067] As a preferred embodiment of any of the third aspect of the present application, in step (6), the first electrode contacts the conductive film.

[0068] After the inflation or deflation is completed, the second electrode contacts the liquid medium.

[0069] Preferably, the first electrode contacts the connection area of the conductive film.

[0070] As a preferred embodiment of any of the third aspect of the present application, in step (6), the pressure difference between the inside and outside of the microcavity chamber is controlled to be 10-140 kPa.

[0071] Further, the pressure difference between the inside and outside of the microcavity can be any value taken from any of the following ranges: 10-140 kPa, 10-130 kPa, 10-120 kPa, 10-110 kPa, 10-100 kPa, 10-90 kPa, 10-80 kPa, 10-70 kPa, 10-60 kPa, 10-50 kPa, 10-40 kPa, 10-30 kPa, 10-20 kPa, 20-100 kPa, 30-100 kPa, 40-100 kPa, 50-100 kPa, 60-100 kPa, 70-100 kPa, 80-100 kPa, 90-100 kPa, 20-120 kPa, 30-120 kPa, 40-120 kPa, 50-120 kPa, 60-120 kPa, 70-120 kPa, 80-120 kPa, 90-120 kPa, 100-120 kPa, 20-140 kPa, 30-140 kPa, 40-140 kPa, 50-140 kPa, 60-140 kPa, 70-140 kPa, 80-140 kPa, 90-140 kPa, 100-140 kPa, 120-140 kPa.

[0072] As a preferred embodiment of any of the third aspects of the present application, in step (6), the flow rate is controlled by a gas flow meter during the process of inflating or deflating.

[0073] As a preferred embodiment of any of the third aspects of the present application, in step (6), the pressure in the chamber is detected by a gas pressure sensor during the process of inflating or deflating.

[0074] As a preferred embodiment of any of the third aspects of the present application, the conductive film has any one or more of the following conditions:

[0075] (I) a thickness of 0.3 nm to 15 nm; further, the thickness can be any value taken from any of the following ranges: 0.3-13 nm, 0.3-11 nm, 0.3-10 nm, 0.3-8 nm, 0.3-6 nm, 0.3-4 nm, 0.33-1 nm;

[0076] (II) a contact angle of less than 90° in an unpowered state; further, the contact angle can be any value taken from any of the following ranges: 10-80°, 20-70°, 30-60°;

[0077] (III) the elastic modulus is 10-1500 N / m; further, the elastic modulus can be any value taken from any of the following numerical ranges: 50-1400 N / m, 80-1300 N / m, 100-1200 N / m, 100-1000 N / m, 100-800 N / m, 100-700 N / m, 100-600 N / m, 100-500 N / m;

[0078] (IV) the pre-tension is 0.1-1.0 N / m; further, the elastic modulus can be any value taken from any of the following numerical ranges: 0.1-0.8 N / m, 0.1-0.7 N / m, 0.1-0.6 N / m, 0.1-0.5 N / m;

[0079] (V) the conductive thin film material includes but is not limited to graphene, molybdenum disulfide, nanometal (metal type is inert metal) film.

[0080] As a preferred embodiment of any of the technical solutions of the third aspect of the present application, the substrate has any one or more of the following conditions:

[0081] (I) the thickness is 300-1000 nm; further, the thickness can be any value taken from any of the following numerical ranges: 300-900 nm, 300-800 nm, 300-700 nm, 300-600 nm, 300-500 nm;

[0082] (II) the resistivity is not less than 1×10 10 Ω·m; further, the resistivity can be any value taken from any of the following numerical ranges: 1×10 11 Ω·m-1×10 20 Ω·m, 1×10 12 Ω·m-1×10 20 Ω·m, 1×10 13 Ω·m-1×10 20 Ω·m, 1×10 14 -1×10 20 Ω·m;

[0083] (III) the material of the substrate includes but is not limited to silicon nitride, silicon oxide;

[0084] (IV) the substrate has a hole with a radius of 1-15 microns.

[0085] As a preferred embodiment of any of the technical solutions of the third aspect of the present application, the liquid medium has any one or more of the following conditions:

[0086] (I) the liquid medium includes but is not limited to any one, two or more of water, electrolyte;

[0087] (II) the ion concentration of the liquid medium is 0-10 mol / L; further, the ion concentration can be any value taken from any of the following numerical ranges: 0.1-10 mol / L, 0.1-8 mol / L, 0.1-6 mol / L, 0.1-4 mol / L, 0.1-2 mol / L, 0.1-1 mol / L, 1-10 mol / L, 3-10 mol / L, 5-10 mol / L, 7-10 mol / L, 9-10 mol / L;

[0088] (III) the liquid medium is preferably an electrolyte solution, and the electrolyte solution contains ion types including but not limited to one or more of potassium ion, sodium ion, lithium ion, hydrogen ion, chloride ion, nitrate ion, sulfate ion;

[0089] (VI) the electrolyte solution includes but is not limited to acid solution, base solution, salt solution.

[0090] As a preferred embodiment of any of the third aspect of the present application, the material of the electrode includes but is not limited to titanium, gold, platinum, nickel.

[0091] As a preferred embodiment of any of the third aspect of the present application, the type of gas filled includes but is not limited to air, nitrogen, argon.

[0092] As a preferred embodiment of any of the third aspect of the present application, the material of the chamber wall of the microcavity includes but is not limited to aluminum, stainless steel, polytetrafluoroethylene.

[0093] The fourth aspect of the present application provides an application of the mechanical resonator according to any of the first aspect of the present application, or the forced resonator device according to any of the second aspect of the present application, or the mechanical resonator manufactured by the manufacturing method according to any of the third aspect of the present application, for sensing, detecting, monitoring or analyzing in a liquid environment.

[0094] As a preferred embodiment of any of the fourth aspect of the present application, for biomedical detection, environmental monitoring, chemical analysis.

[0095] As a preferred embodiment of any of the fourth aspect of the present application, the biomedical detection includes but is not limited to biomolecule detection, cell analysis.

[0096] As a preferred embodiment of any of the fourth aspect of the present application, the environmental monitoring includes but is not limited to water quality monitoring, ocean monitoring.

[0097] As a preferred form of any of the technical solutions of the fourth aspect of the present application, the chemical analysis includes, but is not limited to, liquid component analysis and chemical reaction monitoring.

[0098] Advantages

[0099] Compared with the prior art, the present application has the following advantages:

[0100] (1) The mechanical resonator provided by the present application is based on the basic structure of a conductive thin film and a chamber with an internal-external air pressure difference and containing a liquid medium, and realizes the combination of electrowetting driving and deformation of the conductive thin film. At the same time, the electrodes of the mechanical resonator can be connected to an external alternating current as a power source to periodically regulate the interfacial tension between the conductive thin film and the liquid medium, thereby driving the conductive thin film to produce out-of-plane periodic vibration, and the mechanical resonator is particularly suitable for efficient excitation of the mechanical resonator in a liquid environment.

[0101] (2) The mechanical resonator provided by the present application has low-voltage driving and tunability. Specifically, the mechanical resonator provided by the present application can produce measurable periodic mechanical vibration under an excitation voltage of ten millivolts. By adjusting the amplitude and frequency of the alternating current and the gas pressure in the chamber, a multi-dimensional adjustable vibration response can be achieved, which greatly improves the excitation efficiency, reduces the system energy consumption, and simplifies the design of the external control circuit.

[0102] (3) The mechanical resonator provided by the present application has strong interfacial stability and is suitable for use in a liquid environment. The required driving voltage is significantly lower than the potential window of reactions such as electrolysis of water in a liquid environment (the driving voltage of electrolysis of water is generally not lower than 1.23 V) and electrochemical intercalation (the driving voltage of electrochemical intercalation is generally not lower than 0.1 V), and has excellent chemical stability, ensuring the long-term working reliability of the device.

[0103] (4) The mechanical resonator provided by the present application is a new type of liquid environment mechanical resonator with simple structure, efficient driving, and strong chemical stability, which provides a new technical route for micro-nano mechanical excitation and sensing in a liquid medium, and has a broad application prospect, and is particularly suitable for use in the fields of micro-electro-mechanical liquid environment sensing and interface response regulation.

[0104] (5) The forced resonant device provided by the present application is a new type of liquid environment mechanical resonator with simple structure, efficient driving, and strong chemical stability. BRIEF DESCRIPTION OF DRAWINGS

[0105] Figure 1 is a sectional view of the mechanical resonator provided by the present application in the front view direction of a specific form;

[0106] Figure 2 is a sectional view of the mechanical resonator provided by the present application in the front view direction of another specific form; is a sectional view of the mechanical resonator provided by the present application in the front view direction of another specific form;

[0107] Figure 3 Scatter plot of amplitude versus applied voltage and gas pressure response of the mechanical resonator provided for Example 1 in a liquid environment;

[0108] Explanation of reference numerals in the drawings:

[0109] 100, mechanical resonator;

[0110] 110, conductive thin film; 110a, geometric center of the conductive thin film; 110b, geometric edge of the conductive thin film; 111, resonance region; 112, connection region;

[0111] 120, substrate; 120a, above the substrate; 120b, below the substrate; 121, partial region; 122, through-hole;

[0112] 130, microcavity; 131, cavity; 132, cavity wall; 133, gas port; 134, seal;

[0113] 140, liquid medium;

[0114] 150, gas cavity;

[0115] 210, first electrode; 220, second electrode;

[0116] 300, excitation voltage. DETAILED DESCRIPTION

[0117] The present application will be further described below in conjunction with specific embodiments.

[0118] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order to not unnecessarily obscure the present application. The specific embodiments of the present application are not intended to be exhaustive or to be limited to the precise forms disclosed. The specific embodiments were chosen and described

[0119] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0120] In addition, the terms "first", "second", etc. are used only for descriptive purposes and do not connote or imply relative importance of the indicated elements or numbering thereof. Thus, a feature defined with "first" or "second" can include at least one of the features, explicitly or implicitly. In the description of the present application, the meaning of "a plurality" is at least two, for example, two, three, etc., unless otherwise specifically defined.

[0121] In the present application, unless otherwise specifically indicated and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be interpreted broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate media, or the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically defined. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0122] In the present application, unless otherwise specifically indicated and limited, the first feature is "on" or "under" the second feature can be direct contact between the first and second features, or indirect contact between the first and second features through intermediate media. Moreover, the first feature "on", "above" and "above" the second feature can be the first feature directly above or obliquely above the second feature, or only indicate that the first feature is higher than the second feature in horizontal height. The first feature "under", "below" and "below" the second feature can be the first feature directly below or obliquely below the second feature, or only indicate that the first feature is lower than the second feature in horizontal height.

[0123] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can be a middle element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there can be a middle element. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and are not the only implementation.

[0124] In the description of steps in the patent application file (such as technical solutions, specification), the labels "(1), (2), (3)" are only used to clearly distinguish different operation links, and do not represent the actual execution sequence. The core function of these labels is to decompose complex processes into independent units (for example, "(1) Prepare the substrate", "(2) Fix the conductive film to the side above the substrate …", "(3) Prepare the microcavity with a cavity", etc.), which facilitates the reader to understand the specific content of each link; The actual sequence between the processes needs to be determined through textual description (such as "first perform … then execute …", "may be implemented simultaneously …") or logical deduction. That is, the label is only an identification tool, and the sequence is based on the logic of the technical solution or clear instructions.

[0125] The application will be further described below with reference to the accompanying drawings.

[0126] 1. The application provides a mechanical resonator structure:

[0127] Reference Figure 1 , Figure 2 The mechanical resonator 100 provided by the application includes a substrate 120, a conductive film 110 located above the substrate 120a, a cavity 131 located below the substrate 120b, and a first electrode 210 and a second electrode 220.

[0128] The substrate 120 has at least a partial area 121 with a through hole 122, and the aperture size of the through hole 122 is not particularly limited. The conductive film 110 is arranged above the substrate 120 corresponding to the partial area 121 of the substrate 120 with the through hole 122, and can form complete coverage of the through hole 122 of the substrate 120. The substrate 120 cooperates with the conductive film 110 to form a seal for the cavity 131. Due to the pressure difference between the inside and outside of the cavity 131, the conductive film 110 is deformed by the pressure difference through the through hole 122; At the same time, the cavity 131 also has a liquid medium 140, which contacts the conductive film 110 located above the substrate 120 through the through hole 122 on the substrate 120. Based on this structure, the first electrode 210 contacts the conductive film 110, and the second electrode 220 contacts the liquid medium 140.

[0129] The substrate 120 is an insulating substrate, or the substrate 120 has a resistivity of not less than 1x10 10 Ω·m (for example, the resistivity can be 1x10 11 Ω·m ~1x10 20 Ω·m, or 1x10 12 Ω·m ~1x10 20 Ω·m, or 1x1013 Ω·m ~1×10 20 Ω·m, or 1 x 10 14 ~1×10 20 Ω·m; and a substrate 120, which can be made of a material such as silicon nitride or silicon oxide, and which serves, among other things, to support the conductive thin film 110, and which can have a thickness selected from any of the following ranges: 300-1000 nm, 300-900 nm, 300-800 nm, 300-700 nm, 300-600 nm, 300-500 nm. In some embodiments of the application, the substrate 120 has a thickness of 300-900 nm. In other embodiments of the application, the substrate 120 is made of silicon nitride or silicon oxide.

[0130] The chamber wall 132 of the chamber 131 can be made of aluminum, stainless steel or polytetrafluoroethylene, and the chamber 131 can further have a gas cavity 150 therein, with the liquid medium 140 being in a direction close to the substrate 120, and the gas cavity 150 being in a direction away from the substrate 120. In some embodiments of the application, the chamber wall 132 of the chamber 131 is provided with a gas port 133 and a seal 134, and the gas port 133 can be used to inflate or deflate the gas cavity 150, so as to form a pressure difference between the inside and outside of the chamber 131. When inflation is used, the gas type can be air, nitrogen or argon.

[0131] The conductive film 110 further comprises a resonance region 111 and a connecting region 112; the resonance region 111 is close to the geometric center 110a of the conductive film, and the connecting region 112 is close to the geometric edge 110b of the conductive film. The resonance region 111 substantially corresponds to the position of the region on the substrate 120 with the through hole 122. Under the action of the force formed by the pressure difference inside and outside the chamber 131, the liquid medium 140 filled in the aforementioned chamber 131 contacts the resonance region 111 of the conductive film 110 above the substrate 120 through the through hole 122 on the substrate 120, and under the action of the force, the resonance region 111 of the conductive film 110 protrudes away from the substrate 120 (compared to the connecting region 112 of the conductive film 110), or the resonance region 111 of the conductive film 110 protrudes towards the inside of the chamber 131 (compared to the connecting region 112 of the conductive film 110). In some embodiments of the present application, the elastic modulus of the conductive film 110 needs to meet any value taken from any of the following numerical ranges: 10-1500 N / m, 50-1400 N / m, 80-1300 N / m, 100-1200 N / m, 100-1000 N / m, 100-800 N / m, 100-700 N / m, 100-600 N / m, 100-500 N / m, or the pre-tension needs to meet any value taken from any of the following numerical ranges: 0.1-1.0 N / m, 0.1-0.8 N / m, 0.1-0.7 N / m, 0.1-0.6 N / m, 0.1-0.5 N / m, under the premise of meeting the requirements of electrical conductivity. In some other embodiments of the present application, the thickness of the conductive film 110 can be any value taken from any of the following numerical ranges: 0.3-15 nm, 0.3-13 nm, 0.3-11 nm, 0.3-10 nm, 0.3-8 nm, 0.3-6 nm, 0.3-4 nm, 0.33-1 nm. In some other embodiments of the present application, the contact angle of the conductive film 110 in the unpowered state is less than 90°, such as the contact angle can be any value taken from any of the following numerical ranges: 10-80°, 20-70°, 30-60°. In some other embodiments of the present application, the material of the conductive film 110 can be any of graphene, molybdenum disulfide, and nano-metal (the metal type is inert metal, commonly such as gold, platinum, palladium, silver, etc.). The material of the conductive film 110 can also be other materials with similar properties to the materials listed in the present application and the same function.

[0132] One of the roles of the liquid medium 140 is to form contact with the conductive thin film 110 and the second electrode 220 respectively, based on which, when the conductive thin film 110 is connected with the first electrode 210 and the liquid medium 140 is connected with the second electrode 220 by the excitation voltage 300, the electro wetting effect can be generated, therefore, the liquid medium 140 can be pure water or a solution containing pure water, and preferably, the liquid medium 140 is an electrolyte solution containing electrolyte, typically, an acid solution, an alkali solution, or a salt solution. In some embodiments of the present application, the ion concentration of the liquid medium 140 is 0-10 mol / L, or the ion concentration of the liquid medium 140 is 0.1-8 mol / L, or the ion concentration of the liquid medium 140 is 0.1-6 mol / L, or the ion concentration of the liquid medium 140 is 0.1-4 mol / L, or the ion concentration of the liquid medium 140 is 0.1-2 mol / L, or the ion concentration of the liquid medium 140 is 0.1-1 mol / L, or the ion concentration of the liquid medium 140 is 1-10 mol / L, or the ion concentration of the liquid medium 140 is 3-10 mol / L, or the ion concentration of the liquid medium 140 is 5-10 mol / L, or the ion concentration of the liquid medium 140 is 7-10 mol / L, or the ion concentration of the liquid medium 140 is 9-10 mol / L. In some other embodiments of the present application, the liquid medium 140 is an electrolyte solution containing electrolyte, and the types of ions contained in the electrolyte solution include but are not limited to one or more of potassium ion, sodium ion, lithium ion, hydrogen ion, chloride ion, nitrate ion, and sulfate ion. In some other embodiments of the present application, the type of the liquid medium 140 can be HCl solution, NaCl solution, KCl solution, or LiCl solution.

[0133] The material of the first electrode 210 and the second electrode 220 can be any one, two or more of titanium, gold, platinum, and nickel. The arrangement of the first electrode 210 and the second electrode 220 can be adjusted according to actual use or requirements. Figure 2 However, when it is desired to reduce the volume of the mechanical resonator 100, it is suggested to directly form the first electrode 210 on the side of the substrate upper portion 120a and form the second electrode 220 on the side of the substrate lower portion 120b by using an electron beam evaporation technique.

[0134] On the basis of the above, the excitation voltage 300 is electrically connected with the electrodes of any one of the mechanical resonators 100 described above to form a forced resonator device.

[0135] 2. The present application provides an explanation of the working principle of the mechanical resonator 100: the electrodes of the mechanical resonator 100 can be electrically connected with an external excitation voltage;

[0136] Before power on: After inflation (take inflation as an example for illustration) operation, the air pressure difference is generated between the inside and outside of the chamber 131, under the action of the air pressure difference, the conductive film 110 is deformed to appear the bubble structure (initial state bubble), at the same time, the liquid medium 140 in the chamber 131 contacts with the conductive film 110 through the through hole 122 on the substrate 120.

[0137] After power on: Because the electrodes are respectively connected with the conductive film 110 and the liquid medium 140, the double electric layer of the solid-liquid interface of the conductive film 110 and the liquid medium 140; in the process of the periodic change of the alternating current, when the voltage is not zero, the double electric layer charges like a parallel plate capacitor, the stored electric energy reduces the solid-liquid interface tension between the conductive film 110 and the liquid medium 140, compared with the initial state bubble, the structure deflection of the bubble structure of the conductive film 110 is further increased; with the voltage change to zero in the process of the periodic change of the alternating current, at this time, the electric field is also cancelled, the conductive film 110 returns to the initial state bubble. Thus, by applying the alternating current, the double electric layer is continuously charged and discharged, which causes the conductive film 110 to produce continuous periodic motion, i.e. forced vibration.

[0138] It should be noted that the deflection change of the bubble can be regulated by regulating the size of the electric field, the greater the electric field, the greater the deflection change. In addition, the higher the ion concentration in the liquid medium 140, the smaller the double electric layer spacing between the conductive film 110 and the liquid medium 140, the greater the stored static electric energy under the same electric field, and the greater the deflection change.

[0139] 3. The application provides a preparation method of the mechanical resonator for reference:

[0140] (1) Prepare an insulating substrate 120, the substrate 120 at least exists a partial area 121, the partial area 121 has a through hole 122;

[0141] The first electrode 210 and the second electrode 220 are respectively arranged on the side of the upper surface of the substrate 120a and the side of the lower surface of the substrate 120b; the forming method of the electrode on the surface of the substrate 120 can adopt electron beam evaporation technology or other technology.

[0142] (2) Fix the conductive film 110 to the upper surface of the substrate 120, and ensure that the conductive film 110 is in effective contact with the first electrode 210;

[0143] The specific method of this step is illustrated by way of example: the conductive film 110 is transferred to the side of the upper surface of the substrate 120a by dry transfer technology, and is in contact with the first electrode 210;

[0144] When dry transfer is performed, PMMA (polymethyl methacrylate) is used as an auxiliary material;

[0145] After the transfer is completed, PMMA is removed by acetone immersion;

[0146] After the immersion is completed, the sample is dried using a carbon dioxide supercritical drying instrument. The foregoing can reduce the structural damage caused by the surface tension of the liquid during the drying process.

[0147] (3) A microcavity 130 with an unsealed cavity 131 is prepared, and the microcavity 130 is a semi-closed microcavity with one side open;

[0148] The cavity wall 132 of the microcavity 130 is provided with a gas port 133 and a sealing member 134, the gas port 133 can be used to inflate or exhaust the sealed cavity 131, and the sealing member 134 can seal the gas port 133;

[0149] The microcavity 130 with the cavity 131 can be obtained by 3D printing;

[0150] (4) Liquid medium 140 is added to the cavity 131 of the microcavity 130 through the opening on one side;

[0151] (5) The substrate 120 covered with the conductive film 110 is installed on the opening side of the microcavity 130, so that the cavity 131 of the microcavity 130 is closed;

[0152] (6) The sealed cavity 131 is inflated or exhausted through the gas port 133 of the microcavity 130, so that the pressure difference is formed inside and outside the cavity 131 of the microcavity 130; during the inflation process, the flow is controlled by a gas flow meter, and the pressure in the cavity 131 is detected by a gas pressure sensor;

[0153] After the inflation or exhaustion is completed, the gas port 133 is sealed by the sealing member 134.

[0154] In summary, the mechanical resonator or forced resonator device provided by the application can be applied to sensing, detection, monitoring or analysis in a liquid environment. Typical examples include biomedical detection (such as biomolecule detection and cell analysis), environmental monitoring (water quality monitoring and marine monitoring), and chemical analysis (such as liquid component analysis and chemical reaction monitoring).

[0155] In liquid environments, mechanical resonators can serve as highly sensitive mass sensors for detecting biomolecules or cells. For example, when biomolecules (such as DNA, proteins, antibodies, etc.) or cells adsorb onto the surface of a resonator, the resonator's mass increases, causing a change in its resonant frequency. By measuring this frequency change, quantitative detection of biomolecules or cells can be achieved, aiding in the early diagnosis and treatment monitoring of diseases.

[0156] For example, in aquatic environments, mechanical resonators can be used to detect heavy metal ions, microorganisms, and organic pollutants in water. By modifying the surface of the resonator with specific recognition materials, it can selectively bind to target pollutants, thereby enabling rapid and accurate detection of pollutant concentrations based on frequency changes.

[0157] For example, it is used to measure physical parameters such as seawater density and salinity. In the complex liquid environment of the ocean, the vibration characteristics of mechanical resonators are affected by the physical properties of seawater. By monitoring and analyzing these changes in characteristics, important data support can be provided for marine scientific research and marine resource development.

[0158] For example, in chemical experiments and industrial production, mechanical resonators can be used to analyze the composition of liquid mixtures. When liquids of different compositions come into contact with the resonator, they change the properties of the medium surrounding the resonator, thereby affecting its vibration frequency, which can be used to determine the content and properties of each component in the liquid.

[0159] For example, it can monitor the progress and kinetic parameters of chemical reactions in liquid environments in real time. For instance, by observing changes in the resonator frequency during a chemical reaction, we can understand the consumption of reactants and the formation of products, providing a basis for optimizing chemical reaction conditions.

[0160] Example 1

[0161] Based on the foregoing description of "Detailed Implementation", the mechanical resonator of this embodiment is as follows: Figure 2 As shown. In this embodiment, the substrate 120 is an insulating silicon nitride (SiN) substrate with a through hole 122. x Substrate 120 has a thickness of 500 nm and a resistivity of 1 × 10⁻⁶. 16 Ω·m, the diameter of the through hole 122 is 15 micrometers.

[0162] The conductive film 110 is a single-layer graphene film prepared by mechanical exfoliation, with a thickness of 0.33 nm, a contact angle of 30~60° in the unenergized state, an elastic modulus of 340 N / m, and a pretension of 0.3~0.8 N / m.

[0163] Liquid medium 140 is a KCl solution with a KCl concentration of 0.1 mol / L.

[0164] The microcavity 130 is obtained by 3D printing, and the material of the cavity 131 is stainless steel.

[0165] Nitrogen gas is filled into the closed cavity 131 through the gas port 133 of the microcavity 130, and the pressure in the cavity 131 can be controlled by filling gas. In this embodiment, tests are respectively carried out for pressures of 20 kPa, 40 kPa and 60 kPa.

[0166] In this embodiment, the vibration response signal of the resonator is detected by a laser Doppler vibration detector. First, the response signal of the mechanical resonator in a liquid environment with respect to the excitation frequency is tested, and the frequency scanning range is 1-3.25 MHz, and the resonance frequency is about 3 MHz.

[0167] In order to further explore the vibration response of the mechanical resonator in the liquid environment with respect to the amplitude of the excitation voltage, the vibration signals under voltages of 10 mV, 20 mV, 30 mV, 40 mV and 50 mV are respectively tested.

[0168] In order to avoid the influence of the amplitude nonlinearity caused by the resonance peak and the interference of the resonance peak position shift caused by the internal pressure change, the excitation frequency of 1.6 MHz far away from the resonance peak is used for the voltage amplitude change test.

[0169] As shown in Figure 3 In the liquid environment, with the rise of the excitation voltage, the vibration amplitude of the mechanical resonator can be smoothly and finely adjusted, and can be flexibly adapted to different working scenarios in the liquid environment. Figure 3 The dashed line is a linear fitting curve, which shows that the vibration response of the mechanical resonator approximately presents a linear trend in the voltage range of 0-50 mV. This trend can be explained by a theoretical model: after applying the excitation voltage, the electrostatic energy stored in the double-layer structure at the solid-liquid interface between the conductive film 110 and the liquid medium 140 will change the interfacial tension, and the change amount can be referred to formula (1):

[0170] Formula (1)

[0171] In the formula:

[0172] Δγ sl (V) is the surface tension change amount caused by the electric field, unit: N / m;

[0173] c is the double-layer capacitance density, unit: F / m 2 ;

[0174] V is the applied excitation voltage, unit: mV;

[0175] V pzcZero charge potential of the interface (0.1 M KCl solution corresponds to a zero charge potential of 0.5 V), unit: V;

[0176] When , the following can be obtained . Since the out-of-plane deflection of the conductive film 110 bubble is modulated by the interfacial tension, its response amount at a small pressure level can be referred to formula (2):

[0177] Formula (2)

[0178] In the formula:

[0179] Δδ is the deflection change, unit: m;

[0180] δ is the initial deflection, unit: m;

[0181] T pre is the pre-tension of the graphene film, unit: N / m;

[0182] γ sv is the interfacial tension between the conductive film 110 and the gas in the cavity, unit: N / m;

[0183] γ sl is the solid-liquid interfacial tension between the conductive film 110 and the liquid medium 140, unit: N / m;

[0184] Δγ sl (V) is the change amount of surface tension caused by the electric field, unit: N / m;

[0185] V is the applied excitation voltage, unit: mV;

[0186] Wherein, at low voltage and small pressure level, the denominator is approximately constant, the deflection change Δδ is linearly related to the voltage amplitude V, which is consistent with the experimental results shown in Figure 3 .

[0187] In addition, by adjusting the pressure difference between the inside and outside of the chamber 131 to change the gas pressure (back pressure) inside the conductive film 110 bubble, the vibration amplitude of the mechanical resonator can also be effectively controlled, and the amplitude increases with the increase of the gas pressure. The reason is that increasing the pressure inside the chamber 131 can effectively increase the initial deflection δ of the conductive film 110 bubble, further enhance the solid-liquid interfacial response of the conductive film 110 and the liquid medium 140, and thus provide an additional dimension for vibration control. The theoretical model verifies the feasibility and effectiveness of the electro-wetting and pressure cooperative modulation in the mechanical resonator provided by the present application.

[0188] In summary, the mechanical resonator provided by the present application can drive the conductive film 110 to vibrate periodically by applying a low-amplitude alternating voltage (i.e., an excitation voltage) to the solid-liquid interface of the conductive film 110 and the liquid medium 140, and regulating the solid-liquid interfacial tension of the conductive film 110 and the liquid medium 140 by using the electrowetting effect. In the specific mechanical resonator provided in the present embodiment, the amplitude of the applied alternating electric field is only 0-50 mV. On this basis, by adjusting the parameters (amplitude and frequency) of the alternating electric signal and the pressure inside the chamber 131, the vibration response of the mechanical resonator can be flexibly controlled, multi-dimensional tuning can be achieved, the driving efficiency of the mechanical resonator can be significantly improved, and the system energy consumption and cost can be reduced. Moreover, the amplitude of the excitation voltage applied to the mechanical resonator is only 0-50 mV, which can effectively avoid the occurrence of electrolytic water and electrochemical intercalation, and the mechanical resonator has excellent chemical stability.

[0189] In summary, the mechanical resonator provided by the present application provides a new driving principle and structural design idea for micro-nano mechanical resonators, and is especially suitable for use in a liquid environment, and has good application prospects and research value in typical fields such as micro-electro-mechanical liquid environment sensing, flexible biochips, and interface response research.

[0190] The above description is only an embodiment of the present application for more clearly illustrating the content of the application, and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A mechanical resonator, characterized by, The mechanical resonator comprises: a substrate (120), the substrate (120) is an insulating substrate, and the substrate (120) has at least a partial area (121) with a through hole (122); A conductive film (110) above the substrate (120); A cavity (131) below the substrate (120), the substrate (120) cooperates with the conductive film (110) to form a seal for the cavity (131), there is a pressure difference between the inside and outside of the cavity (131), and the conductive film (110) is deformed under the action of the pressure difference; the cavity (131) has a liquid medium (140) therein, and the liquid medium (140) contacts the conductive film (110) above the substrate (120) through the through hole (122) on the substrate (120); A first electrode (210) in contact with the conductive film (110); A second electrode (220) in contact with the liquid medium (140); The cavity (131) has an air cavity (150) therein, the liquid medium (140) is located in a direction close to the substrate (120), and the air cavity (150) is located in a direction away from the substrate (120); The liquid medium (140) in the cavity (131) contacts the conductive film (110) above the substrate (120) through the through hole (122) on the substrate (120).

2. The mechanical resonator of claim 1, wherein, The conductive film (110) comprises a resonance area (111) and a connecting area (112); The resonance area (111) is close to the geometric center (110a) of the conductive film, and the connecting area (112) is close to the geometric edge (110b) of the conductive film; The resonance area substantially corresponds to the position of the area on the substrate (120) with the through hole (122); Compared with the connecting area (112) of the conductive film (110), the resonance area (111) protrudes in a direction away from the substrate (120); And the liquid medium (140) in the cavity (131) contacts the resonance area (111) through the through hole (122).

3. The mechanical resonator according to any one of claims 1 to 2, wherein The first electrode (210) is arranged above the substrate (120) and contacts the conductive film (110); The second electrode (220) is arranged below the substrate (120) and contacts the liquid medium (140).

4. The mechanical resonator of claim 3, wherein, The cavity wall (132) of the cavity (131) is provided with an air port (133) and a sealing member (134) for sealing the air port (133).

5. The mechanical resonator of claim 4, wherein, The conductive film (110) has any one or more of the following conditions: (I) The thickness is 0.3 nm to 15 nm; (II) The contact angle is less than 90° in an unpowered state; (III) The elastic modulus is 10-1500 N / m; (IV) The pre-tension is 0.1-1.0 N / m; (V) The material includes one or more of graphene, molybdenum disulfide, and nano metal.

6. The mechanical resonator according to claim 4 or 5, characterized in that The substrate (120) has any one or more of the following conditions: (I) thickness is 300-1000 nm; (II) resistivity not less than 1 x 10 10 Ω-m; (III) material includes one or both of silicon nitride and silicon oxide; The liquid medium (140) has any one or more of the following conditions: (I) is an aqueous solution, or an electrolyte-containing solution; (II) the electrolyte-containing solution contains one or more of potassium ion, sodium ion, lithium ion, hydrogen ion, chloride ion, nitrate ion, and sulfate ion; (III) ion concentration is 0-10 mol / L.

7. A forced resonance device, characterized by A mechanical resonator and an excitation voltage; The excitation voltage is electrically connected to an electrode of the mechanical resonator; The mechanical resonator is as claimed in any one of claims 1-6.

8. A method of manufacturing a mechanical resonator, characterized by, The method comprises the steps of: S1. Preparing a substrate (120), the substrate (120) being an insulating substrate, and the substrate (120) having at least a partial region (121) having a through-hole (122); A first electrode (210) is disposed on the side above the substrate (120), and a second electrode (220) is disposed on the side below the substrate (120); S2. Fixing a conductive film (110) to the side above the substrate (120), and ensuring that the conductive film (110) is in contact with the first electrode (210); S3. Preparing a microcavity (130) having a cavity (131), the cavity (131) of the microcavity (130) being a semi-closed microcavity having an opening on one side; The cavity wall (132) of the microcavity (130) is provided with an air port (133) and a sealing member (134); The sealing member (134) can seal the air port (133); S4. Adding a liquid medium (140) into the cavity (131) of the microcavity (130) through the opening on one side; S5. Mounting the substrate (120) to the opening side of the microcavity (130); S6. Filling or evacuating the cavity (131) through the air port (133) of the microcavity (130) to form a pressure difference inside and outside the cavity (131) of the microcavity (130).

9. Use of a mechanical resonator as claimed in any one of claims 1 to 6, characterized in that Sensing, detecting, monitoring, or analyzing in a liquid environment.

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