Temperature self-compensation two-dimensional material resonance MEMS pressure sensor and measurement and preparation method thereof

Abstract

The invention discloses a temperature self-compensation two-dimensional material resonance MEMS pressure sensor which comprises a silicon pressure sensitive film, a two-dimensional material pressure sensitive film, a two-dimensional material temperature compensation film, a glass sealing cover and a glass capillary tube. The upper surface of the silicon pressure sensitive film is provided with two blind holes for placing the two-dimensional material pressure sensitive film and the two-dimensional material temperature compensation film respectively; a deep cavity used as a pressure sensitive area is etched on the lower surface; the two-dimensional material pressure sensitive film is used as a pressure sensitive harmonic oscillator after being subjected to vacuum packaging, is sensitive to pressure and temperature changes at the same time, and is connected with one or more two-dimensional material pressure sensitive film detection optical fibers; the two-dimensional material temperature compensation film is arranged at the edge position of the upper surface of the silicon pressure sensitive film and is connected with one or more two-dimensional material temperature compensation film detection optical fibers; the glass sealing cover is used for providing a vacuum environment; the glass capillary is used for fixing the two-dimensional material pressure sensitive film detection optical fiber and the two-dimensional material temperature compensation film detection optical fiber. The invention further discloses a corresponding measuring method and a preparation method.

Description

Technical Field

[0001] The present invention relates to the technical field of micro / nano electromechanical systems, and in particular to a temperature self-compensating two-dimensional material resonant MEMS pressure sensor, a measuring method and a preparation method. Background Art

[0002] A resonant sensor is a sensor that uses a resonant element (such as a vibrating string, a vibrating cylinder, a vibrating beam, a vibrating membrane, etc.) to convert the measured parameter into a frequency signal, also known as a frequency sensor. Its working principle is based on the resonance principle. When the measured parameter changes, the natural vibration frequency of the vibrating element will change. The measuring device converts this frequency change into an electrical signal output, thereby realizing the measurement of the measured parameter. The resonant pressure sensor is based on measuring the natural frequency of the resonant element as a function of pressure. When the external pressure acts on the sensitive element of the sensor, the sensitive element will deform, causing a change in the equivalent stiffness, resulting in a change in the resonant natural frequency. Compared with traditional pressure sensors, it has the advantages of miniaturization, integration, high sensitivity, good stability, high resolution, fast response and digital output. At present, this type of sensor usually uses metal, quartz or silicon materials as resonators, and is excited and detected by electrical or optical means. For optical methods, an intensity-modulated laser beam can be used to photothermally excite the resonator vibration, and then the excited resonance is detected by optical interferometry. Compared with electrical resonant sensors, optical fiber resonant sensors have the advantages of miniaturization, high sensitivity, resistance to electromagnetic interference, strong multiplexing capability, and membrane protection.

[0003] Graphene has excellent properties, such as single atomic layer thickness, high Young's modulus, high thermal conductivity, and excellent fatigue performance. Its overload capacity is far superior to materials such as silicon, so graphene film has good potential as a resonant sensitive film. Graphene-based nanoelectromechanical systems (NEMS) have been applied to pressure sensors. Graphene can be used as an ultra-sensitive membrane to detect pressure. Replacing the traditional silicon membrane in the traditional MEMS pressure sensor with a graphene membrane will significantly improve its responsiveness and reduce its size. However, the current research on graphene resonant pressure sensors is still limited to laboratory environments, and most of them focus on theoretical discussions of graphene resonant characteristics and experimental verification. In 2017, Beijing University of Aeronautics and Astronautics produced a dual graphene resonant beam pressure sensor (CN106918420A) to achieve quasi-differential measurement and eliminate the influence of environmental factors such as temperature. The sensor is completely based on the principle of electrical excitation and electrical detection, which is different from the optical excitation / pickup method used in the present invention. In 2019, Steeneken et al. from Delft University of Technology in the Netherlands proposed a method to prevent gas leakage between the interface of graphene and SiO2. By using electron beam induced deposition technology to deposit SiO2 on the edge of suspended multilayer graphene sheets, the gas permeability between graphene and SiO2 substrate was reduced by 10 4 times. In 2021, Li Cheng and others from Beijing University of Aeronautics and Astronautics disclosed a vacuum-encapsulated graphene resonant fiber pressure sensor and its manufacturing method (CN2021100376236), but the sensor did not include a temperature compensation structure, resulting in low measurement accuracy. In 2022, Wang Yiping's research group at Shenzhen University reported an ultra-high-sensitivity optomechanical Au / graphene film gas pressure sensor. The Au / graphene film was attached to a hollow-core optical fiber to make a FP resonant pressure sensor with a resolution as low as 7.16×10 -9 mbar, but its graphene film is in direct contact with the environment to be tested, and has limitations such as low stability. In 2024, More et al. from the Indian Institute of Science manufactured a graphene resonant pressure sensor on a SiO2 diaphragm and used an overall packaging structure to generate a pressure difference on the diaphragm. Compared with the probe structure, the sensor cannot be placed alone in the environment to be tested, which limits its application range to a certain extent.

[0004] In addition, for graphene resonant pressure sensors, environmental factors such as temperature and air damping can cause changes in the resonant frequency, which will not only reduce the measurement accuracy of the sensor, but also have an adverse effect on its working stability. Summary of the invention

[0005] In order to solve the problem of temperature drift of graphene resonant pressure sensors in the prior art, the present invention provides the following technical solutions: a temperature self-compensating two-dimensional material resonant MEMS pressure sensor, a measurement method and a preparation method, wherein the differential structure of the dual two-dimensional material resonators used can effectively compensate for the influence of temperature, thereby improving the sensitivity, accuracy and stability of the sensor, having the advantages of small size, strong anti-interference ability and high stability, and having important application value in deep space pressure detection, automotive industry and other fields.

[0006] In one aspect, the present invention provides a temperature self-compensating two-dimensional material resonant MEMS pressure sensor, comprising:

[0007] A silicon pressure sensitive film (1), a two-dimensional material pressure sensitive film (2), a two-dimensional material temperature compensation film (3), a glass cover (4) and a glass capillary (5); wherein:

[0008] Two blind holes are arranged on the upper surface of the silicon pressure sensitive film (1), and the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) are placed in the two blind holes respectively; the lower surface of the silicon pressure sensitive film (1) is etched to form a deep cavity, and the deep cavity is used as a pressure sensitive area, and the structural size of the deep cavity is adjusted according to the pressure environment to be measured and the sensitivity requirement;

[0009] The two-dimensional material pressure sensitive film (2) is arranged at the center of the upper surface of the silicon pressure sensitive film (1); the two-dimensional material pressure sensitive film (2) is vacuum-encapsulated and acts as a pressure sensitive resonator, and is sensitive to pressure and temperature changes at the same time; the two-dimensional material pressure sensitive film (2) is connected to one or more two-dimensional material pressure sensitive film detection optical fibers (6); under the photothermal excitation of the two-dimensional material pressure sensitive film detection optical fibers (6), the two-dimensional material pressure sensitive film (2) resonates, and the pressure to be measured directly acts on the lower surface of the silicon pressure sensitive film (1) to cause it to deform, thereby causing the equivalent stiffness of the two-dimensional material pressure sensitive film (2) to change, and changing the resonant frequency of the two-dimensional material pressure sensitive film (2); based on the change in the resonant frequency, the corresponding relative change in the pressure to be measured is calculated;

[0010] The two-dimensional material temperature compensation film (3) is arranged at the edge of the upper surface of the silicon pressure sensitive film (1), and the two-dimensional material temperature compensation film (3) is connected to one or more two-dimensional material temperature compensation film detection optical fibers (7); the two-dimensional material temperature compensation film (3) has the property of not being affected by the pressure to be measured but only being affected by changes in ambient temperature;

[0011] The glass cover (4) is arranged on the upper surface of the silicon pressure sensitive film (1), and is packaged with the silicon pressure sensitive film (1) through an anodic bonding process, and the glass cover (4) is used to provide a vacuum environment for the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3);

[0012] The glass capillary (5) is arranged on the upper surface of the glass cover (4) and is used to fix the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7), so that the optical fiber output light energy of the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) can be irradiated onto the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) through the glass cover (4) respectively, and reflected back to the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) respectively.

[0013] Preferably, the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) have consistent shapes and geometric dimensions and are in a vacuum environment.

[0014] Preferably, the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) are single-layer or multi-layer, and are in the form of a circular, square, double-end fixed-support vibration beam or patterned structure.

[0015] Preferably, the excitation-detection method adopted by the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) is consistent, which is any one of an optical excitation-optical detection method, an electrical excitation-electrical detection method, an optical excitation-electrical detection method and an electrical excitation-optical detection method.

[0016] Preferably, the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) are any one of single-mode optical fibers, multi-mode optical fibers, or fusion-spliced ​​components of optical fibers and optical devices.

[0017] Preferably, the materials of the two-dimensional material pressure sensitive film (2), the two-dimensional material temperature compensation film (3), the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) are graphene films, hBN films, MXene films, black phosphorus films or transition metal sulfide films.

[0018] Preferably, the glass used for the glass cover (4) has high optical transmittance and a thermal expansion coefficient close to that of silicon material; the glass is Pyrex7740 glass or glass of the same type.

[0019] Preferably, the glass capillary (5) is any material with high optical transmittance that can be micro-processed or machined, including any one of polymethyl methacrylate, polycarbonate and polystyrene.

[0020] A second aspect of the present invention is to provide a pressure measurement method of a temperature self-compensating two-dimensional material resonant MEMS pressure sensor, comprising:

[0021] Silicon pressure sensitive film (1), two-dimensional material pressure sensitive film (2), two-dimensional material temperature compensation film (3), glass cover (4) and glass capillary (5)

[0022] S1, vacuum-encapsulating a two-dimensional material pressure sensitive film (2) and arranging it at the center of the upper surface of the silicon pressure sensitive film (1); arranging the two-dimensional material temperature compensation film (3) at the edge of the upper surface of the silicon pressure sensitive film (1); the two-dimensional material pressure sensitive film (2) acts as a pressure sensitive resonator, and is sensitive to both pressure and temperature changes; the two-dimensional material temperature compensation film (3) is only sensitive to temperature changes;

[0023] S2, under the stimulation of the two-dimensional material pressure sensitive film detection optical fiber (6) connected to the two-dimensional material pressure sensitive film (2), the two-dimensional material pressure sensitive film (2) generates resonance, and the initial resonance frequency of the two-dimensional material pressure sensitive film (2) is recorded;

[0024] S3, under the stimulation of a two-dimensional material temperature compensation film detection optical fiber (7) connected to the two-dimensional material temperature compensation film (3), the two-dimensional material temperature compensation film (3) generates resonance; and the initial resonance frequency of the two-dimensional material temperature compensation film (3) is recorded;

[0025] S4, the pressure to be measured directly acts on the lower surface of the silicon pressure sensitive film (1) to cause it to deform, thereby causing the equivalent stiffness of the two-dimensional material pressure sensitive film (2) to change, and changing the resonance frequency of the two-dimensional material pressure sensitive film (2);

[0026] S5, the temperature change acts on the two-dimensional material temperature compensation film (3), and changes the resonance frequency of the two-dimensional material temperature compensation film (3);

[0027] S6, eliminating the temperature effect by using the differential resonance frequency between the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); the differential resonance frequency is expressed as the pressure sensitivity and temperature sensitivity of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3);

[0028] S7, based on the change of the resonant frequency and the differential resonant frequency, the corresponding pressure to be measured is calculated and outputted. The calculation formula of the pressure to be measured p outputted by the pressure sensor is expressed as formula (1) as follows:

[0029]

[0030] In formula (1), and are the initial resonance frequencies of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3), respectively; f r1 and f r2 are respectively the actual resonant frequencies of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); k1 and k2 are respectively the pressure sensitivities of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); s1 and s2 are respectively the temperature sensitivities of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3).

[0031] The third aspect of the present invention is to provide a method for preparing a temperature self-compensating two-dimensional material resonant MEMS pressure sensor, including: a micromachining process flow and an assembly process flow;

[0032] Wherein, the micromachining process comprises the following steps:

[0033] (A) thermally oxidizing a clean silicon wafer to grow a silicon dioxide layer on the surface of the silicon wafer, and etching two grooves on the surface of the silicon dioxide layer to prevent the glass cover (4) from directly contacting the two-dimensional material resonator after anodic bonding;

[0034] (B) performing secondary etching at the centers of the two grooves by RIE process to form blind holes as the substrates of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3);

[0035] (C) performing back etching on the lower surface of the silicon wafer to form a cavity as a pressure sensitive area, thereby forming the silicon pressure sensitive film (1);

[0036] (D) transferring polymethyl methacrylate, the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) to the surface of the blind holes on the two circular grooves on the surface of the silicon dioxide layer by dry transfer, adsorbing them on the silicon pressure sensitive film (1) under the action of van der Waals force, and placing the silicon, the two-dimensional material film and polymethyl methacrylate in a high-temperature annealing furnace in a nitrogen environment for annealing to remove the polymethyl methacrylate on the graphene surface, thereby forming a fixed-support suspended two-dimensional material structure above the blind hole;

[0037] (E) depositing a layer of SiO2 around the two-dimensional material film by a FIB process, for clamping and fixing the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3);

[0038] (F) using a glass wafer as a sealing material, bonding the glass wafer and the silicon pressure sensitive film (1) through a vacuum anodic bonding process, aligning one side of the silicon wafer with the graphene film and the unprocessed side of the glass wafer for anodic bonding, vacuum packaging the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) under vacuum conditions, and mechanically cutting to obtain an independent sensor unit;

[0039] (G) respectively fixing the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) in the central and edge holes of the glass capillary (5), aligning with the center of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3), and fixing with high temperature resistant glue to form a complete micro-machined part of the MEMS pressure sensor;

[0040] The assembly process includes:

[0041] (A) Making a fixture for an optical fiber ferrule, comprising: assembling the fixture on a micro-movement platform by screws, so that the micro-movement platform can perform micro-displacement adjustment over a long distance;

[0042] (B) respectively fixing the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) to the glass capillary (5), including: cutting the center of the single-mode optical fiber jumper, stripping the bare fiber at one end and cutting the end face flat, inserting the single-mode optical fiber into the fixing hole of the glass capillary (5), and making the end face of the optical fiber flush with the end face of the glass capillary (5), and then sealing the tail of the optical fiber capillary with high temperature resistant liquid glue to fix the optical fiber and the glass capillary (5);

[0043] (C) adjusting the position of the optical fiber end face, comprising: inserting the glass capillary (5) into the clamp, and adjusting the position of the optical fiber end face by means of the micro-motion stage, so that a clear optical fiber end face can be seen at the center of the microscope eyepiece, and at this time, the optical fiber end face is on the focal plane of the microscope; then adjusting the micro-motion stage to keep the relative positions of the micro-motion stage, the clamp and the optical fiber fixed;

[0044] (D) loading a visible light source, including: connecting an end of the optical fiber jumper to a red visible light laser source, and adjusting the output optical power of the red visible light source so that the clear aperture at the center of the optical fiber can be observed through a microscope;

[0045] (E) roughly adjusting the distance between the thin film formed by the two-dimensional material and the end face of the optical fiber, including: fixing the silicon pressure sensitive film (1) on the bracket of the two-dimensional material resonator packaging structure, so that the upper surface of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) is 1 mm away from the end face of the optical fiber, so as to prevent the resonator from contacting the end face of the optical fiber, thereby causing mechanical damage to the optical fiber or the packaged resonator structure; then adjusting the position of the micro-motion stage so that a clear image of the graphene and the substrate is presented in the field of view;

[0046] (F) finely adjusting the distance between the thin film formed by the two-dimensional material and the end face of the optical fiber, comprising: irradiating the output light of a broadband light source to the thin film surfaces of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3), receiving the reflected light by a spectrometer, and detecting the cavity length in real time through the reflection spectrum data of the thin film formed by the two-dimensional material;

[0047] (G) adjusting the position of the glass capillary (5) so that the reflected light spots of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) are coaxial with the fiber end faces of the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7), and the red light spots emitted from the centers of the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) are located at the center of the pressure sensitive resonator;

[0048] (H) fixing the assembly formed by the silicon pressure sensitive film (1) and the glass cover plate (4) to the glass capillary (5), including: after completing the alignment of the relative positions of the red light spot and the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3), fixing the glass cover plate (4) to the glass capillary (5), thereby completing the assembly of the temperature self-compensating two-dimensional material resonant MEMS pressure sensor.

[0049] A fourth aspect of the present invention provides an electronic device, comprising a processor and a memory, wherein the memory stores a plurality of instructions, and the processor is used to read the instructions and execute the method as described in the second aspect.

[0050] A fifth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a plurality of instructions, and the plurality of instructions can be read by a processor and executed by the method described in the second aspect.

[0051] The method, system and electronic device provided by the present invention have the following beneficial effects:

[0052] (1) The present invention adopts an indirect sensitive structure, and the pressure to be measured does not contact the graphene resonator, which can effectively protect the graphene resonator and improve the long-term stability and reliability of the sensor.

[0053] (2) The present invention can measure pressure scenarios in a variety of environments, including gas pressure and liquid pressure. At the same time, the size of the pressure sensitive area can be adjusted according to the pressure range to be measured and the sensitivity requirements, and has high flexibility.

[0054] (3) The present invention adopts a dual graphene resonator sensing structure and operates in a differential mode, which can compensate for errors caused by the environment, improve the accuracy of the sensor, and is applicable to pressure measurement in complex temperature environments.

[0055] (4) The test system used in the assembly method of the present invention has a simple structure, small space occupancy, high cost performance, and convenient operation, and can realize the assembly of the pressure-sensitive unit and the optical fiber.

[0056] (5) The thickness of the double graphene resonator used in the present invention is in the nanometer range, which is much lower than that of the traditional silicon resonator. This can greatly improve the sensitivity of the pressure sensor and provide the possibility for the small integration of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a schematic diagram of the principle structure of the temperature self-compensating two-dimensional material resonant MEMS pressure sensor described in the present invention.

[0058] Figure 2 This is a schematic diagram of the anodic bonding micromachining process method of the temperature self-compensating two-dimensional material resonant MEMS pressure sensor described in the present invention.

[0059] Figure 3 This is a flow chart of the assembly method of the temperature self-compensating two-dimensional material resonant MEMS pressure sensor described in the present invention.

[0060] Figure 4 FIG. 1 is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention.

[0061] The meanings of the reference numerals in the figure are:

[0062] 1-Silicon pressure sensitive film; 2-Two-dimensional material pressure sensitive film; 3-Two-dimensional material temperature compensation film;

[0063] 4-glass cover; 5-glass capillary; 6-two-dimensional material pressure sensitive film detection optical fiber;

[0064] 7- Two-dimensional material temperature compensation film detection optical fiber. DETAILED DESCRIPTION

[0065] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0066] Embodiment 1

[0067] This embodiment provides a temperature self-compensating two-dimensional material resonant MEMS pressure sensor, including:

[0068] Silicon pressure sensitive film 1, two-dimensional material pressure sensitive film 2, two-dimensional material temperature compensation film 3, glass cover 4 and glass capillary 5; wherein:

[0069] Two blind holes are arranged on the upper surface of the silicon pressure sensitive film 1, and the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 are placed in the two blind holes respectively; the lower surface of the silicon pressure sensitive film 1 is etched to form a deep cavity, which is used as a pressure sensitive area, and the structural size of the deep cavity is adjusted according to the pressure environment to be measured and the sensitivity requirements;

[0070] The two-dimensional material pressure sensitive film 2 is arranged at the center of the upper surface of the silicon pressure sensitive film 1. The two-dimensional material pressure sensitive film 2 is used as a pressure sensitive resonator after being vacuum packaged, and is sensitive to pressure and temperature changes at the same time; the two-dimensional material pressure sensitive film 2 is connected to one or more two-dimensional material pressure sensitive film detection optical fibers 6; under the photothermal excitation of the two-dimensional material pressure sensitive film detection optical fibers 6, the two-dimensional material pressure sensitive film 2 resonates, and the pressure to be measured directly acts on the lower surface of the silicon pressure sensitive film 1 to cause it to deform, thereby causing the two-dimensional material pressure sensitive film 2 to undergo an equivalent stiffness change, and changing the resonant frequency of the two-dimensional material pressure sensitive film 2; the relative change of the corresponding pressure to be measured is calculated based on the change in the resonant frequency;

[0071] The two-dimensional material temperature compensation film 3 is arranged at the edge of the upper surface of the silicon pressure sensitive film 1, and the two-dimensional material temperature compensation film 3 is connected to one or more two-dimensional material temperature compensation film detection optical fibers 7; the two-dimensional material temperature compensation film 3 has the property of not being affected by the pressure to be measured but only by the change of the ambient temperature, and is only sensitive to the temperature change, and the temperature effect is eliminated by detecting the differential resonance frequency of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3;

[0072] The glass cover 4 is arranged on the upper surface of the silicon pressure sensitive film 1 and is packaged with the silicon pressure sensitive film 1 by an anodic bonding process. The glass cover 4 is used to provide a vacuum environment for the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3;

[0073] The glass capillary 5 is arranged on the upper surface of the glass cover 4, and is used to fix the two-dimensional material pressure sensitive film detection optical fiber 6 and the two-dimensional material temperature compensation film detection optical fiber 7, so that the optical fiber output light energy of the two-dimensional material pressure sensitive film detection optical fiber 6 and the two-dimensional material temperature compensation film detection optical fiber 7 can be irradiated onto the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 through the glass cover 4, and reflected back to the two-dimensional material pressure sensitive film detection optical fiber 6 and the two-dimensional material temperature compensation film detection optical fiber 7, respectively.

[0074] As a preferred embodiment, the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 have consistent shapes and geometric dimensions and are in a vacuum environment; the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 are single-layer or multi-layer, and are circular, square, double-end fixed-support vibration beam or patterned structural forms.

[0075] As a preferred embodiment, the excitation-detection method adopted by the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 is consistent, which is any one of the optical excitation-optical detection method, the electrical excitation-electrical detection method, the optical excitation-electrical detection method and the electrical excitation-optical detection method.

[0076] As a preferred embodiment, the two-dimensional material pressure sensitive film detection optical fiber 6 and the two-dimensional material temperature compensation film detection optical fiber 7 are either single-mode optical fibers, multi-mode optical fibers or fusion-spliced ​​components of optical fibers and optical devices.

[0077] As a preferred embodiment, the materials of the two-dimensional material pressure sensitive film 2, the two-dimensional material temperature compensation film 3, the two-dimensional material pressure sensitive film detection optical fiber 6 and the two-dimensional material temperature compensation film detection optical fiber 7 are graphene film, hBN film, MXene film, black phosphorus film or transition metal sulfide film.

[0078] As a preferred embodiment, the glass used for the glass cover 4 has high optical transmittance and a thermal expansion coefficient close to that of silicon material; the glass is Pyrex7740 glass or the same type of glass, and the glass cover 4 can be of any thickness.

[0079] As a preferred embodiment, the glass capillary 5 is any material with high optical transmittance that can be micro-processed or machined, such as polymethyl methacrylate (PMMA), polycarbonate (PC), PS (polystyrene) and other light-transmitting materials of the same type.

[0080] Embodiment 2

[0081] This embodiment provides a pressure measurement method of a temperature self-compensating two-dimensional material resonant MEMS pressure sensor, comprising:

[0082] Silicon pressure sensitive film 1, two-dimensional material pressure sensitive film 2, two-dimensional material temperature compensation film 3, glass cover 4 and glass capillary 5

[0083] S1, vacuum encapsulate the two-dimensional material pressure sensitive film 2 and set it at the center of the upper surface of the silicon pressure sensitive film 1; set the two-dimensional material temperature compensation film 3 at the edge of the upper surface of the silicon pressure sensitive film 1; the two-dimensional material pressure sensitive film 2 acts as a pressure sensitive resonator, sensitive to pressure and temperature changes at the same time; the two-dimensional material temperature compensation film 3 is only sensitive to temperature changes;

[0084] S2, under the excitation of the two-dimensional material pressure sensitive film detection optical fiber 6 connected to the two-dimensional material pressure sensitive film 2, the two-dimensional material pressure sensitive film 2 generates resonance, and the initial resonance frequency of the two-dimensional material pressure sensitive film 2 is recorded;

[0085] S3, under the excitation of the two-dimensional material temperature compensation film detection optical fiber 7 connected to the two-dimensional material temperature compensation film 3, the two-dimensional material temperature compensation film 3 generates resonance; and the initial resonance frequency of the two-dimensional material temperature compensation film 3 is recorded;

[0086] S4, the pressure to be measured directly acts on the lower surface of the silicon pressure sensitive membrane 1 to cause it to deform, thereby causing the equivalent stiffness of the two-dimensional material pressure sensitive membrane 2 to change, and changing the resonance frequency of the two-dimensional material pressure sensitive membrane 2;

[0087] S5, the temperature change acts on the two-dimensional material temperature compensation film 3, and changes the resonance frequency of the two-dimensional material temperature compensation film 3;

[0088] S6, eliminating the temperature effect by using the differential resonance frequency between the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3; the differential resonance frequency is expressed as the pressure sensitivity and temperature sensitivity of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3;

[0089] S7, based on the change of the resonant frequency and the differential resonant frequency, the corresponding pressure to be measured is calculated and outputted. The calculation formula of the pressure to be measured p outputted by the pressure sensor is expressed as formula (1) as follows:

[0090]

[0091] In formula (1), and are the initial resonant frequencies of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 respectively; f r1 and f r2 are the actual resonant frequencies of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 respectively; k1 and k2 are the pressure sensitivities of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 respectively; s1 and s2 are the temperature sensitivities of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 respectively.

[0092] Embodiment 3

[0093] This embodiment provides a method for preparing a temperature self-compensating two-dimensional material resonant MEMS pressure sensor, including: a micromachining process flow and an assembly process flow;

[0094] The micromachining process includes the following steps:

[0095] (A) thermally oxidizing a clean silicon wafer to grow a silicon dioxide layer on the surface of the silicon wafer, and etching two grooves on the surface of the silicon dioxide layer to prevent the glass cover 4 from directly contacting the two-dimensional material resonator after anodic bonding;

[0096] (B) performing secondary etching at the center of the two grooves by RIE process to form blind holes as the substrate of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3;

[0097] (C) performing back etching on the lower surface of the silicon wafer to form a cavity as a pressure sensitive area, thereby forming a silicon pressure sensitive film 1;

[0098] (D) transferring polymethyl methacrylate (PMMA), a two-dimensional material pressure sensitive film 2 and a two-dimensional material temperature compensation film 3 to the surface of the blind holes on the two circular grooves on the surface of the silicon dioxide layer by dry transfer, adsorbing them on the silicon pressure sensitive film 1 under the action of van der Waals force, and placing the silicon, the two-dimensional material film and polymethyl methacrylate (PMMA) in a high-temperature annealing furnace in a nitrogen environment for annealing for 3 hours, thereby removing the polymethyl methacrylate (PMMA) on the graphene surface and forming a fixed-support suspended two-dimensional material structure above the blind hole;

[0099] (E) depositing a layer of SiO2 around the two-dimensional material film by FI B process, which is used to clamp and fix the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3;

[0100] (F) Using a glass wafer as a sealing material, the glass wafer and the silicon pressure sensitive film 1 are subjected to a vacuum anodic bonding process, one side of the silicon wafer with the graphene film is aligned with the unprocessed side of the glass wafer for anodic bonding, vacuum packaging of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 is performed under vacuum conditions, and mechanical cutting is performed to obtain an independent sensor unit;

[0101] (G) Fixing the two-dimensional material pressure sensitive film detection optical fiber 6 and the two-dimensional material temperature compensation film detection optical fiber 7 in the central and edge holes of the glass capillary 5 respectively, and aligning the centers of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3, and fixing them with high temperature resistant glue to form a complete micro-machined part of the MEMS pressure sensor;

[0102] The assembly process includes:

[0103] (A) Making a fixture for an optical fiber ferrule, comprising: assembling the fixture on a micro-movement platform by screws, so that the micro-movement platform can perform micro-displacement adjustment over a long distance;

[0104] (B) The two-dimensional material pressure sensitive film detection optical fiber 6 and the two-dimensional material temperature compensation film detection optical fiber 7 are respectively fixed to the glass capillary 5, including: cutting the center of the single-mode optical fiber jumper, stripping the bare fiber at one end and cutting the end face flat, inserting the single-mode optical fiber into the fixing hole of the glass capillary 5, and making the optical fiber end face flush with the end face of the glass capillary 5, and then sealing the tail of the optical fiber capillary with high temperature resistant liquid glue to fix the optical fiber and the glass capillary 5.

[0105] (C) adjusting the position of the optical fiber end face, including: inserting the glass capillary 5 into the clamp, and adjusting the position of the optical fiber end face through the micro-motion stage, so that the optical fiber end face can be clearly seen in the center of the microscope eyepiece, and the optical fiber end face is on the focal plane of the microscope; then adjusting the micro-motion stage to keep the relative positions of the micro-motion stage, the clamp and the optical fiber fixed.

[0106] (D) loading a visible light source, including: connecting an end of the optical fiber jumper to a red visible light laser source, and adjusting the output optical power of the red visible light source so that the clear aperture at the center of the optical fiber can be observed through a microscope;

[0107] (E) Roughly adjusting the distance between the thin film formed by the two-dimensional material and the end face of the optical fiber, including: fixing the silicon pressure sensitive film 1 on the bracket of the two-dimensional material resonator packaging structure, so that the upper surface of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 are about 1 mm away from the end face of the optical fiber, so as to prevent the resonator from contacting the end face of the optical fiber, thereby causing mechanical damage to the optical fiber or the packaged resonator structure; then adjusting the position of the micro-motion stage to present a clear image of the graphene and the substrate in the field of view, at this time, the upper surface of the glass cover plate of the graphene resonator packaging structure is about 50 μm away from the end face of the optical fiber where the laser is emitted.

[0108] (F) finely adjusting the distance between the thin film formed by the two-dimensional material and the end face of the optical fiber, including: irradiating the output light of the broadband light source to the thin film surfaces of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3, receiving the reflected light by a spectrometer, and detecting the cavity length in real time through the reflection spectrum data of the thin film formed by the two-dimensional material;

[0109] (G) adjusting the position of the glass capillary 5 so that the reflected light spot of the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3 is coaxial with the fiber end faces of the two-dimensional material pressure sensitive film detection optical fiber 6 and the two-dimensional material temperature compensation film detection optical fiber 7, and the red light spot emitted from the center of the two-dimensional material pressure sensitive film detection optical fiber 6 and the two-dimensional material temperature compensation film detection optical fiber 7 is located at the center of the pressure sensitive resonator;

[0110] (H) fixing the assembly formed by the silicon pressure sensitive film (1) and the glass cover plate 4 to the glass capillary 5, including: after completing the alignment of the relative positions of the red light spot and the two-dimensional material pressure sensitive film 2 and the two-dimensional material temperature compensation film 3, fixing the glass cover plate 4 to the glass capillary 5, thereby completing the assembly of the temperature self-compensating two-dimensional material resonant MEMS pressure sensor.

[0111] In the following examples, graphene is selected as a typical two-dimensional material.

[0112] Figure 1 The schematic diagram of the principle structure of the temperature self-compensating graphene resonant MEMS pressure sensor of the present invention is shown, which mainly includes a silicon pressure sensitive film 1, a graphene pressure sensitive film 2, a graphene temperature compensation film 3, a glass cover 4, a glass capillary 5, a detection optical fiber 6 of the graphene pressure sensitive film, and a detection optical fiber 7 of the graphene temperature compensation film.

[0113] Two grooves are etched on the upper surface of the silicon wafer to prevent the graphene from adhering to the glass during anodic bonding, and then blind holes are etched in the centers of the two grooves to serve as the substrates of the graphene pressure sensitive film 2 and the graphene temperature compensation film 3; a cavity is etched back on the silicon wafer to form the silicon pressure sensitive film 1; the graphene pressure sensitive film 2 and the graphene temperature compensation film 3 are transferred to the surface of the blind holes respectively by dry transfer, wherein the graphene pressure sensitive film 2 is located in the center of the silicon pressure sensitive film 1, and is sensitive to pressure and temperature changes at the same time, and the graphene temperature compensation film 3 is located at the edge of the silicon pressure sensitive film 1 , only sensitive to temperature changes, and eliminating temperature effects by detecting differential resonant frequencies; performing anodically bonding the glass wafer 4 and the silicon pressure sensitive film 1 under vacuum conditions, completing vacuum packaging of the graphene pressure sensitive film 2 and the graphene temperature compensation film 3, and dicing and cutting to obtain independent sensor units; respectively fixing the detection optical fiber 6 of the graphene pressure sensitive film and the detection optical fiber 7 of the graphene temperature compensation film in the central and edge holes of the glass capillary 5, and aligning them with the centers of the graphene pressure sensitive film 2 and the graphene temperature compensation film 3, and fixing them with high temperature resistant glue to form a complete sensor.

[0114] The pressure sensitive measurement principle and working process of this embodiment are:

[0115] The pressure to be measured first acts on the lower surface of the silicon pressure sensitive film 1, causing its upper surface to deform upward, thereby causing the graphene pressure sensitive film 2 located at the center of the upper surface of the silicon pressure sensitive film 1 to deform, thereby changing the resonant frequency and amplitude of the graphene pressure sensitive film 2; at the same time, the graphene temperature compensation film 3 located at the center of the upper surface of the silicon pressure sensitive film 1 does not deform. Since the detection optical fiber 6 of the graphene pressure sensitive film and the detection optical fiber 7 of the graphene temperature compensation film respectively form a Fabry-Perot interference cavity between the graphene pressure sensitive film 2 and the graphene temperature compensation film 3, the amplitude change of the graphene film causes the change of the interference light intensity, and the measurement of the pressure to be measured is achieved by demodulating the interference light intensity.

[0116] The temperature compensation principle and working process of this embodiment are:

[0117] The graphene pressure sensitive film 2 and the graphene temperature compensation film 3 have the same shape and structural dimensions. The graphene pressure sensitive film 2 is sensitive to both pressure and ambient temperature, while the graphene temperature compensation film 3 is only sensitive to ambient temperature. Under different ambient temperatures, the temperature effect is eliminated by detecting the differential resonant frequency.

[0118] This embodiment provides a set of process flows for manufacturing a temperature self-compensated graphene resonant MEMS pressure sensor, wherein the micromachining process flow consists of: Figure 2 Shown, including the following steps:

[0119] Step 1, thermally oxidize a clean 500μm thick silicon wafer 100 to grow a silicon dioxide layer with a thickness of about 10μm on the surface of the silicon wafer, and only etch two circular grooves on the surface of the silicon dioxide layer from the first etching, which are shallow circular grooves with a diameter of 200μm and a depth of about 10μm, to avoid direct contact between the glass cover and the graphene resonator after bonding.

[0120] Step 2: Perform secondary etching in two circular grooves on the surface of the silicon dioxide layer by RIE process to form the substrate of the graphene pressure sensitive film 2 and the graphene temperature compensation film 3.

[0121] Step 3: a pressure sensitive area with a diameter of 5 mm and a thickness of 100 μm is etched from the lower surface of the silicon wafer to form a silicon pressure sensitive film 1 .

[0122] Step 4, transfer the PMMA / graphene film to the two circular grooves on the surface of the silicon dioxide layer, adsorb it on the silicon pressure sensitive film 1 under the action of van der Waals force, and place the silicon / graphene / PMMA in a high-temperature annealing furnace in a nitrogen environment and anneal it at 350°C for 3 hours to remove the PMMA on the graphene surface and form a fixed suspended graphene structure above the blind hole.

[0123] Step 5: deposit a layer of SiO2 around the graphene film by FIB process, which is used to clamp and fix the graphene pressure sensitive film 2 and the graphene temperature compensation film 3.

[0124] Step 6, select a 100 μm thick Pyrex7740 glass wafer 4 as a capping material, and align and bond one side of the silicon wafer with the graphene film to the unprocessed side of the glass wafer through a vacuum anodic bonding process to achieve vacuum packaging of the graphene pressure sensitive film 2 and the graphene temperature compensation film 3.

[0125] Step 7, respectively fix the detection optical fiber 6 of the graphene pressure sensitive film and the detection optical fiber 7 of the graphene temperature compensation film in the central and edge holes of the glass capillary 5, align them with the center of the graphene pressure sensitive film 2 and the graphene temperature compensation film 3, and fix them with high temperature resistant glue to form a complete sensor.

[0126] This embodiment provides a method for assembling a group of temperature self-compensated graphene resonant MEMS pressure sensors. The assembly method flow chart is as follows: Figure 3 Shown, including the following steps:

[0127] Step 1, make a clamp for the optical fiber ferrule: assemble the clamp on the micro-movement table by screws, so that the micro-movement table can perform long-distance micro-displacement adjustment.

[0128] Step 2, respectively fix the detection optical fiber 6 of the graphene pressure sensitive membrane and the detection optical fiber 7 of the graphene temperature compensation membrane to the glass capillary 5: cut the center of the single-mode optical fiber jumper, strip the bare fiber at one end and cut the end face flat, insert the single-mode optical fiber into the fixing hole of the glass capillary, and make the end face of the optical fiber flush with the end face of the glass capillary, then seal the tail of the optical fiber capillary with high temperature resistant liquid glue, and fix the detection optical fiber 6 of the graphene pressure sensitive membrane and the detection optical fiber 7 of the graphene temperature compensation membrane to the glass capillary 5.

[0129] Step 3, adjust the position of the fiber end face: insert the glass capillary into the fixture, and adjust the position of the fiber end face through the micro-motion stage so that the fiber end face can be clearly seen in the center of the microscope eyepiece. At this time, the fiber end face is on the focal plane of the microscope. Then adjust the micro-motion stage to keep the relative positions of the micro-motion stage, fixture, and fiber fixed.

[0130] Step 4, load the visible light source: connect the fiber jumper end to the red visible light laser source, and properly adjust the output optical power of the light source so that the aperture at the center of the optical fiber can be observed through a microscope.

[0131] Step 5, coarsely adjust the distance between graphene and the end face of the optical fiber: customize the bracket of the graphene resonator packaging structure, fix the silicon pressure sensitive film 1 on the bracket, and make the upper surface of the graphene pressure sensitive film 2 and the graphene temperature compensation film 3 about 1-2mm away from the end face of the optical fiber to prevent the resonator from contacting the end face of the optical fiber and causing mechanical damage to the optical fiber or the packaged resonator structure. Then adjust the position of the micro-motion stage to present a clear image of the graphene and the substrate in the field of view. At this time, the distance between the upper surface of the glass cover plate of the graphene resonator packaging structure and the end face of the optical fiber where the laser is emitted is about 50μm.

[0132] Step 6, fine-tuning the distance between graphene and the end face of the optical fiber: irradiate the output light of the broadband light source to the surface of the graphene pressure sensitive film 2 and the graphene temperature compensation film 3, and the reflected light is received by the spectrometer. The cavity length can be detected in real time through the reflection spectrum data of the graphene.

[0133] Step 7, adjust the position of the glass capillary 5 so that the reflected light spot on the graphene pressure sensitive film 2 and the graphene temperature compensation film 3 is coaxial with the fiber end faces of the detection fiber 6 of the graphene pressure sensitive film and the detection fiber 7 of the graphene temperature compensation film, and the red light spot emitted from the center of the optical fiber is located at the center of the graphene resonator.

[0134] Step 8, the assembly of silicon pressure sensitive film 1 / glass cover plate 4 is fixedly connected to the glass capillary 5: after completing the alignment of the relative positions of the light spot and the graphene pressure sensitive film 2 and the graphene temperature compensation film 3, the glass cover plate 4 is fixedly connected to the glass capillary 5 to complete the assembly of the temperature self-compensating graphene resonant MEMS pressure sensor.

[0135] The dimensions of the present invention may be larger or smaller than those given in the embodiments.

[0136] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

[0137] The present invention also provides a memory storing a plurality of instructions, wherein the instructions are used to implement the pressure measurement method and the preparation method.

[0138] like Figure 4 As shown, the present invention also provides an electronic device, including a processor 301 and a memory 302 connected to the processor 301, the memory 302 stores a plurality of instructions, and the instructions can be loaded and executed by the processor so that the processor can execute the method as in the first embodiment.

[0139] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A temperature self-compensating two-dimensional material resonant MEMS pressure sensor, characterized in that: include: A silicon pressure sensitive film (1), a two-dimensional material pressure sensitive film (2), a two-dimensional material temperature compensation film (3), a glass cover (4) and a glass capillary (5); wherein: Two blind holes are arranged on the upper surface of the silicon pressure sensitive film (1), and the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) are placed in the two blind holes respectively; the lower surface of the silicon pressure sensitive film (1) is etched to form a deep cavity, and the deep cavity is used as a pressure sensitive area, and the structural size of the deep cavity is adjusted according to the pressure environment to be measured and the sensitivity requirement; The two-dimensional material pressure sensitive film (2) is arranged at the center of the upper surface of the silicon pressure sensitive film (1); the two-dimensional material pressure sensitive film (2) is vacuum-encapsulated and acts as a pressure sensitive resonator, and is sensitive to pressure and temperature changes at the same time; the two-dimensional material pressure sensitive film (2) is connected to one or more two-dimensional material pressure sensitive film detection optical fibers (6); under the photothermal excitation of the two-dimensional material pressure sensitive film detection optical fibers (6), the two-dimensional material pressure sensitive film (2) resonates, and the pressure to be measured directly acts on the lower surface of the silicon pressure sensitive film (1) to cause it to deform, thereby causing the equivalent stiffness of the two-dimensional material pressure sensitive film (2) to change, and changing the resonant frequency of the two-dimensional material pressure sensitive film (2); based on the change in the resonant frequency, the corresponding relative change in the pressure to be measured is calculated; The two-dimensional material temperature compensation film (3) is arranged at the edge of the upper surface of the silicon pressure sensitive film (1), and the two-dimensional material temperature compensation film (3) is connected to one or more two-dimensional material temperature compensation film detection optical fibers (7); the two-dimensional material temperature compensation film (3) has the property of not being affected by the pressure to be measured but only being affected by changes in ambient temperature; The glass cover (4) is arranged on the upper surface of the silicon pressure sensitive film (1), and is packaged with the silicon pressure sensitive film (1) through an anodic bonding process, and the glass cover (4) is used to provide a vacuum environment for the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); The glass capillary (5) is arranged on the upper surface of the glass cover (4) and is used to fix the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7), so that the optical fiber output light energy of the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) can be irradiated onto the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) through the glass cover (4) respectively, and reflected back to the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) respectively.

2. A temperature self-compensating two-dimensional material resonant MEMS pressure sensor according to claim 1, characterized in that: The two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) have consistent shapes and geometric dimensions and are in a vacuum environment.

3. The temperature self-compensating two-dimensional material resonant MEMS pressure sensor according to claim 2, characterized in that: The two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) are single-layer or multi-layer, and are in the form of a circular, square, double-end fixed-support vibration beam or patterned structure.

4. The temperature self-compensating two-dimensional material resonant MEMS pressure sensor according to claim 3, characterized in that: The excitation-detection method adopted by the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) is consistent, and is any one of an optical excitation-optical detection method, an electrical excitation-electrical detection method, an optical excitation-electrical detection method, and an electrical excitation-optical detection method.

5. The temperature self-compensating two-dimensional material resonant MEMS pressure sensor according to claim 4, characterized in that: The two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) are any one of single-mode optical fibers, multi-mode optical fibers, or fusion-spliced ​​components of optical fibers and optical devices.

6. The temperature self-compensating two-dimensional material resonant MEMS pressure sensor according to claim 5, characterized in that: The materials of the two-dimensional material pressure sensitive film (2), the two-dimensional material temperature compensation film (3), the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) are graphene films, hBN films, MXene films, black phosphorus films or transition metal sulfide films.

7. The temperature self-compensating two-dimensional material resonant MEMS pressure sensor according to claim 6, characterized in that: The glass used in the glass cover (4) has high optical transmittance and a thermal expansion coefficient close to that of silicon material; the glass is Pyrex7740 glass or glass of the same type.

8. The temperature self-compensating two-dimensional material resonant MEMS pressure sensor according to claim 7, characterized in that: The glass capillary (5) is any material with high optical transmittance that can be micro-processed or machined, including any one of polymethyl methacrylate, polycarbonate and polystyrene.

9. A method for measuring pressure of a temperature self-compensating two-dimensional material resonant MEMS pressure sensor according to any one of claims 1 to 8, characterized in that: include: Silicon pressure sensitive film (1), two-dimensional material pressure sensitive film (2), two-dimensional material temperature compensation film (3), glass cover (4) and glass capillary (5) S1, vacuum-encapsulating the two-dimensional material pressure sensitive film (2) and placing it at the center of the upper surface of the silicon pressure sensitive film (1); The two-dimensional material temperature compensation film (3) is arranged at the edge of the upper surface of the silicon pressure sensitive film (1); the two-dimensional material pressure sensitive film (2) acts as a pressure sensitive resonator, being sensitive to both pressure and temperature changes; the two-dimensional material temperature compensation film (3) is only sensitive to temperature changes; S2, under the stimulation of the two-dimensional material pressure sensitive film detection optical fiber (6) connected to the two-dimensional material pressure sensitive film (2), the two-dimensional material pressure sensitive film (2) generates resonance, and the initial resonance frequency of the two-dimensional material pressure sensitive film (2) is recorded; S3, under the stimulation of a two-dimensional material temperature compensation film detection optical fiber (7) connected to the two-dimensional material temperature compensation film (3), the two-dimensional material temperature compensation film (3) generates resonance; and the initial resonance frequency of the two-dimensional material temperature compensation film (3) is recorded; S4, the pressure to be measured directly acts on the lower surface of the silicon pressure sensitive film (1) to cause deformation thereof, thereby causing the equivalent stiffness of the two-dimensional material pressure sensitive film (2) to change, and changing the resonance frequency of the two-dimensional material pressure sensitive film (2); S5, the temperature change acts on the two-dimensional material temperature compensation film (3), and changes the resonance frequency of the two-dimensional material temperature compensation film (3); S6, eliminating the temperature effect by using the differential resonance frequency between the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); the differential resonance frequency is expressed as the pressure sensitivity and temperature sensitivity of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); S7, based on the change of the resonant frequency and the differential resonant frequency, the corresponding pressure to be measured is calculated and outputted. The calculation formula of the pressure to be measured p output by the pressure sensor is expressed as formula (1) as follows: In formula (1), and are the initial resonance frequencies of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3), respectively; f r1 and f r2 are respectively the actual resonant frequencies of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); k1 and k2 are respectively the pressure sensitivities of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); s1 and s2 are respectively the temperature sensitivities of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3).

10. A method for preparing a temperature self-compensating two-dimensional material resonant MEMS pressure sensor according to any one of claims 1 to 8, characterized in that: include: Micro-machining process flow and assembly process flow; Wherein, the micromachining process comprises the following steps: (A) thermally oxidizing a clean silicon wafer to grow a silicon dioxide layer on the surface of the silicon wafer, and etching two grooves on the surface of the silicon dioxide layer to prevent the glass cover (4) from directly contacting the two-dimensional material resonator after anodic bonding; (B) performing secondary etching at the centers of the two grooves by RIE process to form blind holes as the substrates of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); (C) performing back etching on the lower surface of the silicon wafer to form a cavity as a pressure sensitive area, thereby forming the silicon pressure sensitive film (1); (D) transferring polymethyl methacrylate, the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) to the surface of the blind holes on the two circular grooves on the surface of the silicon dioxide layer by dry transfer, adsorbing them on the silicon pressure sensitive film (1) under the action of van der Waals force, and placing the silicon, the two-dimensional material film and polymethyl methacrylate in a high-temperature annealing furnace in a nitrogen environment for annealing to remove the polymethyl methacrylate on the graphene surface, thereby forming a fixed-support suspended two-dimensional material structure above the blind hole; (E) depositing a layer of SiO2 around the two-dimensional material film by FIB process, for clamping and fixing the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3); (F) using a glass wafer as a sealing material, bonding the glass wafer and the silicon pressure sensitive film (1) through a vacuum anodic bonding process, aligning one side of the silicon wafer with the graphene film and the unprocessed side of the glass wafer for anodic bonding, vacuum packaging the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) under vacuum conditions, and mechanically cutting to obtain an independent sensor unit; (G) respectively fixing the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) in the central and edge holes of the glass capillary (5), aligning with the center of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3), and fixing with high temperature resistant glue to form a complete micro-machined part of the MEMS pressure sensor; The assembly process includes: (A) Making a fixture for an optical fiber ferrule, comprising: assembling the fixture on a micro-movement platform by screws, so that the micro-movement platform can perform micro-displacement adjustment over a long distance; (B) respectively fixing the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) to the glass capillary (5), including: cutting the center of the single-mode optical fiber jumper, stripping the bare fiber at one end and cutting the end face flat, inserting the single-mode optical fiber into the fixing hole of the glass capillary (5), and making the end face of the optical fiber flush with the end face of the glass capillary (5), and then sealing the tail of the optical fiber capillary with high temperature resistant liquid glue to fix the optical fiber and the glass capillary (5); (C) adjusting the position of the optical fiber end face, comprising: inserting the glass capillary (5) into the clamp, and adjusting the position of the optical fiber end face by means of the micro-motion stage, so that a clear optical fiber end face can be seen at the center of the microscope eyepiece, and at this time, the optical fiber end face is on the focal plane of the microscope; then adjusting the micro-motion stage to keep the relative positions of the micro-motion stage, the clamp and the optical fiber fixed; (D) loading a visible light source, including: connecting an end of the optical fiber jumper to a red visible light laser source, and adjusting the output optical power of the red visible light source so that the clear aperture at the center of the optical fiber can be observed through a microscope; (E) roughly adjusting the distance between the thin film formed by the two-dimensional material and the end face of the optical fiber, including: fixing the silicon pressure sensitive film (1) on the bracket of the two-dimensional material resonator packaging structure, so that the upper surface of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) is 1 mm away from the end face of the optical fiber, so as to prevent the resonator from contacting the end face of the optical fiber, thereby causing mechanical damage to the optical fiber or the packaged resonator structure; then adjusting the position of the micro-motion stage so that a clear image of the graphene and the substrate is presented in the field of view; (F) finely adjusting the distance between the thin film formed by the two-dimensional material and the end face of the optical fiber, comprising: irradiating the output light of a broadband light source to the thin film surfaces of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3), receiving the reflected light by a spectrometer, and detecting the cavity length in real time through the reflection spectrum data of the thin film formed by the two-dimensional material; (G) adjusting the position of the glass capillary (5) so that the reflected light spots of the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3) are coaxial with the fiber end faces of the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7), and the red light spots emitted from the centers of the two-dimensional material pressure sensitive film detection optical fiber (6) and the two-dimensional material temperature compensation film detection optical fiber (7) are located at the center of the pressure sensitive resonator; (H) fixing the assembly formed by the silicon pressure sensitive film (1) and the glass cover plate (4) to the glass capillary (5), including: after completing the alignment of the relative positions of the red light spot and the two-dimensional material pressure sensitive film (2) and the two-dimensional material temperature compensation film (3), fixing the glass cover plate (4) to the glass capillary (5), thereby completing the assembly of the temperature self-compensating two-dimensional material resonant MEMS pressure sensor.

Images