CN102620878B - Capacitive micromachining ultrasonic sensor and preparation and application methods thereof - Google Patents
Capacitive micromachining ultrasonic sensor and preparation and application methods thereof Download PDFInfo
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Abstract
The invention provides a capacitive micromachining ultrasonic sensor and preparation and application methods thereof. The integral structure of the capacitive micromachining ultrasonic sensor sequentially comprises a monocrystalline silicon vibration film, a silicon dioxide support and a monocrystalline silicon base from top to bottom, a cavity is arranged in the middle of the silicon dioxide support, the middle of the monocrystalline silicon vibration film is heavily doped with boron ions to form a top electrode, the middle of the monocrystalline silicon base is heavily doped with boron ions to form a bottom electrode, and the horizontal size of each of the top electrode and the bottom electrode is smaller than or equal to that of the cavity and larger than a half of that of the cavity. The sensor is simple in structure, low in machining difficulty and suitable for batch production, a sensing resistor and a circuit are not integrated in the vibration film, and both the thickness and the weight of the film can be further decreased, so that measurement with higher sensitivity and smaller range pressure can be realized. As the change of the pressure is measured by means of deviation of resonant frequency, input quantity and output quantity are kept in better linear relationship.
Description
Technical field
The invention belongs to MEMS technical field, relate to a kind of capacitance type micromachined ultrasonic transducer and preparation and application method thereof.
Background technology
Ultra micro low pressure sensor is mainly used in the measurement of slight pressure, it all has urgent demand and application widely in fields such as Industry Control, environmental protection equipment, Medical Devices, Aero-Space and military weapons, thereby the research of such sensor is had to extremely important practical value.
At present, based on MEMS((Micro Electro-Mechanical Systems, micromachine electronic system) the silicon ultra-low-pressure sensor of technology dominates in art of pressure sensors, and obtains business-like widespread use.Silicon ultra-low-pressure sensor, by its principle of work, mainly can be divided into following three kinds: pressure resistance type, condenser type and resonant mode.Pressure resistance type micro-pressure sensor mainly utilizes the piezoresistive effect of silicon, by change in voltage, carrys out gaging pressure size.Although its output has good linear relationship with input, but in silicon thin film, the temperature sensitivity of force sensing resistance requires sensor must carry out temperature compensation, increase the complicacy of measuring, in silicon fiml, integrated its film thickness that causes of Wheatstone bridge is difficult to further reduce under the condition that guarantees measuring accuracy simultaneously, and then be difficult to further reduce range, improve sensitivity.Capacitance silicon micropressure sensor utilizes capacitance pole, apart from changing, pressure is changed to the variation that is converted into electric capacity, have good, highly sensitive, low in energy consumption, the further microminiaturization of the temperature stability series of advantages such as relatively simple that becomes, but its output is poor with linearity of input.Resonant silicon micropressure sensor be utilize the natural frequency of resonance beam with the change that applies axial force, change to realize tonometric, although its measuring accuracy, stability and resolving power are all better than above two kinds, complex structure, difficulty of processing is larger.At present, the range of the slight pressure transducer of silicon is mainly at 1000Pa left and right, minimum reached at 300Pa.Due to the restriction of said structure self, cause it to be difficult to further realize more lower range and more highly sensitive ultralow micro pressure measuring.Thereby herein wish by a kind of CMUT (Capactive Micromachined Ultrasonic Transducer, capacitance type micromachined ultrasonic transducer) that has more structure and performance advantage based on MEMS technology for ultra micro pressure survey.CMUT is one of important research direction of MEMS technology, it has the features such as good electromechanical properties, less film quality, higher resonant frequency (can reach tens MHz) and quality factor (can reach hundreds of), this for further realize more high sensitivity and more small-range press force measurement that possibility is provided; Its simple in structure, easy processing, easily array, the feature such as easy of integration are that low cost, short period, high efficiency are produced in batches and the integrated many advantages that provides of complicated circuit.At present, CMUT is mainly used in the aspects such as ultrasonic imaging, biochemical substances detection, and the research in ultralow micro pressure measuring field yet there are no relevant report.
Summary of the invention
Technical matters to be solved by this invention is to provide a kind of capacitance type micromachined ultrasonic transducer and preparation and application method thereof, capacitance type micromachined ultrasonic transducer is applied to slight pressure to be measured, to solve the difficult problem in current ultralow micro pressure measuring field, realize highly sensitive in 150Hz/Pa and range the ultralow micro pressure measuring lower than 300Pa.
For solving above technical matters, the present invention by the following technical solutions:
A kind of capacitance type micromachined ultrasonic transducer, its one-piece construction is followed successively by from top to bottom: monocrystalline silicon vibration film, silicon dioxide pillar, and monocrystalline silicon pedestal, wherein, part in the middle of described silicon dioxide pillar is cavity, the center section of described monocrystalline silicon vibration film forms top electrode through the heavy doping of boron ion, the center section of described monocrystalline silicon pedestal forms bottom electrode through the heavy doping of boron ion, and the lateral dimension of top electrode and bottom electrode is less than or equal to the lateral dimension of cavity and is greater than half of cavity lateral dimension.
As the preferred embodiments of the present invention, the thickness of described monocrystalline silicon vibration film is 0.06～0.12um;
As the preferred embodiments of the present invention, effective vibration film lateral dimension of described monocrystalline silicon vibration film is 5 μ m～15 μ m, and described effective vibration film is vibration film part more than cavity;
As the preferred embodiments of the present invention, the lateral dimension of described cavity equates with the lateral dimension of effective vibration film, is 5～15 μ m, and cavity height equates with silicon dioxide pillar, is 0.08～0.15 μ m;
As the preferred embodiments of the present invention, the resistivity of described top electrode and bottom electrode is less than 10
-3Ω cm.
A preparation method for capacitance type micromachined ultrasonic transducer, comprises the following steps:
(1) get <111> crystal orientation monocrystalline silicon, adopt local ion implantttion technique at monocrystalline silicon middle part B Implanted ion, make its resistivity be less than 10
-3Ω cm, wherein, heavy doping monocrystalline silicon partly forms bottom electrode, and remainder is CMUT pedestal;
(2) whether using plasma strengthens chemical vapor deposition needs the english abbreviation of this technology herein: PECVD technology is deposition of silica layer on CMUT pedestal, then this silicon dioxide layer of photoetching, form cavity graphical window, then with buffering etching liquid, etch away and be exposed to silicon dioxide layer in graphical window, remaining silicon dioxide layer forms silicon dioxide pillar, finally adopt chemically mechanical polishing CMP technology to carry out polishing to the upper surface of silicon dioxide pillar, form first;
(3) get SOI wafer, adopt dry oxidation technology that the upper surface of the top single crystal silicon wafer of SOI wafer is carried out to dry oxidation and form silicon dioxide layer, the ratio of the single crystal silicon wafer thickness consuming when wherein the thickness of the silicon dioxide layer of oxidation formation is with generation silicon dioxide layer is 1:0.44, and not oxidized part is called monocrystalline silicon layer;
(4) with the silicon dioxide layer that buffering etching liquid forms step (3), etch away, expose not oxidized monocrystalline silicon layer, then, at the middle part of monocrystalline silicon layer, adopt local ion implantttion technique heavy doping boron ion, make its resistivity be less than 10
-3Ω cm, wherein, heavy doping monocrystalline silicon partly forms top electrode, finally the upper surface of monocrystalline silicon layer is carried out to chemically mechanical polishing, forms second portion;
(5) under vacuum environment, the second portion that the first that step (2) is obtained and step (4) obtain carries out anode linkage, wherein, the upper surface of the upper surface of the silicon dioxide pillar of first and the not oxidized monocrystalline silicon layer in top of second portion carries out bonding; Because SOI wafer has dividing of base substrate silicon, buried silicon dioxide layer and top single crystal silicon wafer, only say whether second portion monocrystalline silicon layer cannot distinguish substrate monocrystal silicon and top monocrystalline silicon layer herein.
(6) device step (5) being obtained adopts wet etching to remove successively the substrate monocrystal silicon of SOI wafer and 80% buried silicon dioxide layer from top to bottom, and then remains 20% buried silicon dioxide layer by buffering etching liquid etching.
A kind of application process of capacitance type micromachined ultrasonic transducer, described capacitance type micromachined ultrasonic transducer for realize highly sensitive in 150Hz/Pa and range the ultralow micro pressure measuring lower than 300Pa, concrete grammar is: by simulation analysis and laboratory facilities, jointly determine the best operating point of CMUT, be bias direct current voltage, determine the AC signal of natural resonance frequency and this Frequency point simultaneously, the voltage magnitude of AC signal and bias voltage sum should be less than CMUT collapse voltage, with coupling coefficient, are principle to the maximum; Under determined bias direct current voltage and the excitation of resonance frequency AC signal, there is resonance in CMUT, be placed in slight pressure environment, because pressure-acting is on CMUT vibration film, change CMUT vibrational state, lose resonance, now regulate AC signal frequency, make CMUT that resonance occur again, record this resonance frequency, calculate the poor Δ f of resonance frequency under natural resonance frequency and this pressure-acting, then by the funtcional relationship P=Δ f/k between pressure and frequency displacement, can try to achieve institute's measuring pressure value, realize pressure survey.
Ultralow micro-pressure sensor that the present invention is based on CMUT and preparation method thereof at least has the following advantages:
(1) with respect to pressure resistance type micro-pressure sensor, integrated without force sensing resistance and circuit in CMUT vibration film of the present invention, film thickness and quality all can further reduce, thus can realize more high sensitivity and more small-range press force measurement.
(2) with respect to capacitance-type micro-pressure transducer, the present invention adopts the skew of resonant frequency to carry out the variation of gaging pressure, thereby between input and output quantity, is keeping better linear relationship.
(3) with respect to resonant micro-pressure power sensor, the present invention is simple in structure, and difficulty of processing is little, is suitable for batch production, is easy to integrated.
(4) because CMUT structure of the present invention is only comprised of monocrystalline silicon and two kinds of measurement materials of silicon dioxide, and this bi-material expansion coefficient is identical, thereby structure is applicable to hot environment, its thermal expansivity is very close, and (wherein silicon dioxide thermal expansivity is 2.3 * 10
-6/ ℃, monocrystalline silicon is 2.6 * 10
-6/ ℃), so this structure also can be used for the measurement of slight pressure in hot environment.
Accompanying drawing explanation
Fig. 1 is the structural representation that the present invention is based on the ultralow micro-pressure sensor of CMUT;
Fig. 2 is preparation technology's process flow diagram of sensor of the present invention.
Embodiment
Below in conjunction with accompanying drawing, a kind of capacitance type micromachined ultrasonic transducer of the present invention and preparation and application method thereof are described in detail:
Refer to accompanying drawing 1, the one-piece construction of a kind of capacitance type micromachined ultrasonic transducer of the present invention is followed successively by from top to bottom: monocrystalline silicon vibration film 1, silicon dioxide pillar 2, cavity 6 and monocrystalline silicon pedestal 3.Wherein, monocrystalline silicon vibration film 1 middle part forms top electrode 4 through boron ion heavily doped region, is also that vibration film 1 is used as CMUT top electrode simultaneously, and top electrode 4 is integrated with vibration film 1; Monocrystalline silicon pedestal 3 middle parts form CMUT bottom electrode 5 through boron ion heavily doped region, are also that monocrystalline silicon pedestal 3 is used as bottom electrode simultaneously, and bottom electrode 5 is integrated with pedestal 3.
Described monocrystalline silicon vibration film 1 is except for CMUT vibration film, also for top electrode.Film thickness should be as far as possible little on the one hand, to reduce film quality, and then the sensitivity that improves CMUT, realize more small-range pressure survey; On the other hand, thickness too young pathbreaker increases resistance in series, affects the electric conductivity of top electrode 4; Therefore film thickness scope should be 0.06～0.12um.In addition, known according to the theoretical calculation formula of vibration of thin membrane frequency, obtain high resonant frequency, should reduce surface radius as far as possible, therefore in the present invention, effective vibration film lateral dimension scope of vibration film 1 is 5 μ m～15 μ m, the cavity that effectively vibration film region is vibration film 1 more than 6 or not with the film portion of silicon dioxide pillar 2 bondings.The lateral dimension of top electrode 4 should be less than or equal to cavity 6 lateral dimensions, but should be equal to or greater than its lateral dimension half, to reduce stray capacitance, increase coupling coefficient is principle of design.
Described cavity 6 is circle or polygon, and its lateral dimension is with effectively vibration film lateral dimension is identical, and its range of size is 5 μ m～15 μ m, and height is identical with the height of silicon dioxide pillar 2.
The height of described silicon dioxide pillar 2 is as far as possible little, to reduce cavity height, increases coupling coefficient, and then improves sensitivity, and its altitude range is 0.08～0.15 μ m.
Described monocrystalline silicon pedestal 3, except as the base of whole CMUT structure, is also used as bottom electrode 5 after the heavy doping of boron ion in the middle part of it, bottom electrode 5 is integrated with monocrystalline silicon pedestal 3.The lateral dimension of bottom electrode 5 should be less than or equal to cavity 6 lateral dimensions, but should be equal to or greater than its lateral dimension half, to reduce stray capacitance, increase coupling coefficient is principle of design.
Described top electrode 4 and bottom electrode 5 resistivity after the heavy doping of boron ion should be less than 10
-4Ω cm, to reduce resistance in series, reduces power consumption.
Described top electrode 4, bottom electrode 5 and cavity 6 shapes are identical, coaxial and symmetrical about central shaft.
The material of described vibration film 1, monocrystalline silicon pedestal 3 is monocrystalline silicon, and the material of pillar 2 is silicon dioxide, and this bi-material thermal linear expansion coefficient is very approaching, thereby this structure meets the requirement that in hot environment, slight pressure is measured.
Sensor of the present invention, its main structure parameters is as follows:
Cavity height: 0.08～0.15 μ m
Vibration film thickness: 0.06～0.12um
Effective vibration film lateral dimension: 5 μ m～15 μ m.
Below in conjunction with accompanying drawing 2, preparation technology's flow process of a kind of capacitance type micromachined ultrasonic transducer of the present invention is described in detail:
(1) get <111> crystal orientation monocrystalline silicon, and adopt local ion implantttion technique at monocrystalline silicon middle part B Implanted ion, make its resistivity be less than 10
-3Ω cm, wherein heavy doping monocrystalline silicon partly forms bottom electrode 5, and bottom electrode 5 does not form CMUT pedestal 3 together with doped monocrystalline silicon with all the other simultaneously; Get SOI wafer, top single crystal silicon wafer thickness is 150nm.
(2) using plasma strengthens chemical vapor deposition (Plasma Enhanced Chemical Vapor Deposition, be called for short PECVD) technology deposition of silica layer on CMUT pedestal 3, the strict thickness of controlling silicon dioxide layer, accurately to control the height of the cavity pillar being formed by silicon dioxide, and then accurately control the height of total cavity; Adopt dry oxidation technology that SOI wafer top single crystal silicon wafer 8 upper surfaces are carried out to dry oxidation and form silicon dioxide layer, monocrystalline silicon layer not oxidized in the single crystal silicon wafer 8 of SOI wafer top forms monocrystalline silicon layer 10, and the ratio of the single crystal silicon wafer thickness consuming when wherein the thickness of the silicon dioxide layer of oxidation formation is with generation silicon dioxide layer is 1:0.44.
(3) silicon dioxide layer on photoetching CMUT pedestal 3 upper stratas forms cavity graphical window, adopts the buffering etching liquid of 20:1 to etch away be exposed to silicon dioxide layer in graphical window completely with the shortest time, and remaining silicon dioxide layer forms silicon dioxide pillar 2; With the buffering etching liquid of 20:1, with the shortest time, etch away the silicon dioxide layer on the SOI wafer of right side simultaneously, expose the upper surface of monocrystalline silicon layer 10.
(4) adopt chemical Mechanical Polishing Technique to carry out polishing to the upper surface of left side silicon dioxide pillar 2; At the middle part of right side monocrystalline silicon layer 10, adopt local ion implantttion technique heavy doping boron ion, make its resistivity be less than 10
-3Ω cm, wherein heavy doping monocrystalline silicon partly forms top electrode 4, and top electrode 4 does not form CMUT vibration film 1 together with doped monocrystalline silicon with all the other simultaneously, and then the upper surface of film 1 is carried out to chemically mechanical polishing.
(5) under vacuum environment, the upper surface of the upper surface of left side silicon dioxide pillar 2 and right side vibration film 1 is carried out to anode linkage, wherein SOI wafer is upper, pedestal 3 under.
(6) adopt wet etching to remove successively the substrate monocrystal silicon of SOI and 80% buried silicon dioxide layer from top to bottom, and then with the shortest time etching, remain 20% buried silicon dioxide layer with the buffering etching liquid of 20:1, to guarantee the surface smoothness of vibration film 1.
A kind of capacitance type micromachined ultrasonic transducer of the present invention, be applied to pressure survey field, its principle of work is: under operating voltage (bias direct current voltage) effect, CMUT film deforms because being subject to electrostatic attraction, and basad drawing close now applies the AC signal of certain frequency again, CMUT film will produce the forced vibration identical with signal frequency, the frequency that changes AC signal, when this incoming frequency equals CMUT structure self natural frequency, CMUT will resonate.Resonant frequency at masterpiece with no pressure used time CMUT is the natural frequency of structure self, in the time of on having its film of pressure-acting, will there is corresponding skew in the resonant frequency of CMUT, different pressure correspondences different frequency skew, and pressure and frequency displacement are keeping good linear relationship within the specific limits: Δ f=kP or P=Δ f/k.Wherein Δ f is for the resonant frequency f of the rear CMUT of pressurization is with respect to natural reonant frequency f
0frequency displacement, i.e. Δ f=f
0-f ，Qi unit is Hz; K is transducer sensitivity, and unit is Hz/Pa; P is tested force value, and unit is Pa.Therefore the variation by CMUT resonant frequency can calculate corresponding force value.
When a kind of capacitance type micromachined ultrasonic transducer of the present invention is applied to pressure survey field, its concrete application process is: by simulation analysis and laboratory facilities, jointly determine the best operating point of CMUT, be bias direct current voltage (be generally collapse voltage 80%～90%), determine the AC signal of natural resonance frequency and this Frequency point simultaneously, the voltage magnitude of AC signal and bias voltage sum should be less than CMUT collapse voltage, with coupling coefficient, are principle to the maximum.Under determined bias direct current voltage and the excitation of resonance frequency AC signal, there is resonance in CMUT, be placed in slight pressure environment, because pressure-acting is on CMUT vibration film, change CMUT vibrational state, lose resonance, now regulate AC signal frequency, make CMUT that resonance occur again, record this resonance frequency, calculate the poor Δ f of resonance frequency under natural resonance frequency and this pressure-acting, then by the funtcional relationship P=Δ f/k between pressure and frequency displacement, can try to achieve institute's measuring pressure value, realize pressure survey.
The invention is not restricted to the above embodiment, under condition and technology enabled condition, monocrystalline silicon vibration film 1 also can not adopt SOI wafer by the method for oxidation technology attenuate top single crystal silicon wafer thickness, directly selects top single crystal silicon wafer to meet the SOI wafer of vibration film 1 thickness requirement; Secondly the material of vibration film 1 also can be selected polysilicon, take improve film mechanical property and reduce thickness, quality is principle.The shape of cavity 6 and top electrode 4, bottom electrode 5 except the above shape and dependency structure size can choose flexibly according to practical situations, take and increase effective capacitance, improve coupling coefficient and sensitivity is principle of design.When being applied to hot environment, because the electric conductivity of heavy doping monocrystalline silicon changes according to temperature, thereby should adopt suitable operating voltage according to different temperature conditionss, to guarantee the Measurement accuracy of sensor to slight pressure.In addition, in this structure between top electrode 4 and bottom electrode 5 without electric isolation layer, therefore to corresponding current foldback circuit be set in follow-up metering circuit, prevent film subside after damage to structure self and other relevant devices.
The main performance index of a kind of ultra micro pressure transducer based on CMUT of the present invention is as follows:
Measurement range: 0～100Pa
Measuring accuracy: be better than 2%FS
Sensitivity: 180Hz/Pa
Working temperature :-50～300 ℃
The foregoing is only one embodiment of the present invention, it not whole or unique embodiment, the conversion of any equivalence that those of ordinary skills take technical solution of the present invention by reading instructions of the present invention, is claim of the present invention and contains.
Claims (7)
1. a capacitance type micromachined ultrasonic transducer, it is characterized in that: its one-piece construction is followed successively by from top to bottom: monocrystalline silicon vibration film (1), silicon dioxide pillar (2), and monocrystalline silicon pedestal (3), wherein, part in the middle of described silicon dioxide pillar (2) is cavity (6), the center section of described monocrystalline silicon vibration film (1) forms top electrode through the heavy doping of boron ion, the center section of described monocrystalline silicon pedestal (3) forms bottom electrode through the heavy doping of boron ion, the lateral dimension of top electrode and bottom electrode is less than or equal to the lateral dimension of cavity (6) and is greater than half of cavity (6) lateral dimension.
2. a kind of capacitance type micromachined ultrasonic transducer as claimed in claim 1, is characterized in that: the thickness of described monocrystalline silicon vibration film (1) is 0.06～0.12um.
3. a kind of capacitance type micromachined ultrasonic transducer as claimed in claim 1, it is characterized in that: effective vibration film lateral dimension of described monocrystalline silicon vibration film (1) is 5 μ m～15 μ m, described effective vibration film is the above vibration film part of cavity (6).
4. a kind of capacitance type micromachined ultrasonic transducer as claimed in claim 3, it is characterized in that: the lateral dimension of described cavity (6) equates with the lateral dimension of effective vibration film, be 5～15 μ m, cavity (6) height equates with silicon dioxide pillar (2), is 0.08～0.15 μ m.
5. a kind of capacitance type micromachined ultrasonic transducer as claimed in claim 1, is characterized in that: the resistivity of described top electrode and bottom electrode is less than 10
-3Ω cm.
6. the preparation method of a capacitance type micromachined ultrasonic transducer, it is characterized in that: comprise the following steps: (1) gets <111> crystal orientation monocrystalline silicon, adopt local ion implantttion technique at monocrystalline silicon middle part B Implanted ion, make its resistivity be less than 10
-3Ω cm, wherein, heavy doping monocrystalline silicon partly forms bottom electrode (5), and remainder is CMUT pedestal (3);
(2) using plasma strengthens chemical vapour deposition technique at the upper deposition of silica layer of CMUT pedestal (3), then this silicon dioxide layer of photoetching, form cavity graphical window, then with buffering etching liquid, etch away and be exposed to silicon dioxide layer in graphical window, remaining silicon dioxide layer forms silicon dioxide pillar (2), finally adopt chemical Mechanical Polishing Technique to carry out polishing to the upper surface of silicon dioxide pillar (2), form first;
(3) get SOI wafer, adopt dry oxidation technology that the upper surface of the top single crystal silicon wafer of SOI wafer is carried out to dry oxidation and form silicon dioxide layer, the ratio of the single crystal silicon wafer thickness consuming when wherein the thickness of the silicon dioxide layer of oxidation formation is with generation silicon dioxide layer is 1:0.44, and not oxidized part is called monocrystalline silicon layer;
(4) with the silicon dioxide layer that buffering etching liquid forms step (3), etch away, expose not oxidized monocrystalline silicon layer, then, at the middle part of monocrystalline silicon layer, adopt local ion implantttion technique heavy doping boron ion, make its resistivity be less than 10
-3Ω cm, wherein, heavy doping monocrystalline silicon partly forms top electrode (4), finally the upper surface of monocrystalline silicon layer is carried out to chemically mechanical polishing, forms second portion;
(5) under vacuum environment, the second portion that the first that step (2) is obtained and step (4) obtain carries out anode linkage, and wherein, the upper surface of silicon dioxide pillar (2) of first and the upper surface of the monocrystalline silicon layer of second portion carry out bonding;
(6) device step (5) being obtained adopts wet etching to remove successively the substrate monocrystal silicon of SOI wafer and 80% buried silicon dioxide layer from top to bottom, and then remains 20% buried silicon dioxide layer by buffering etching liquid etching.
7. the application process of a capacitance type micromachined ultrasonic transducer, it is characterized in that: described capacitance type micromachined ultrasonic transducer for realize highly sensitive in 150Hz/Pa and range the ultralow micro pressure measuring lower than 300Pa, concrete grammar is: by simulation analysis and laboratory facilities, jointly determine the best operating point of CMUT, be bias direct current voltage, determine the AC signal of natural resonance frequency and this Frequency point simultaneously, the voltage magnitude of AC signal and bias voltage sum should be less than CMUT collapse voltage, with coupling coefficient, are principle to the maximum; Under determined bias direct current voltage and the excitation of resonance frequency AC signal, there is resonance in CMUT, be placed in slight pressure environment, because pressure-acting is on CMUT vibration film, change CMUT vibrational state, lose resonance, now regulate AC signal frequency, make CMUT that resonance occur again, record this resonance frequency, calculate the poor Δ f of resonance frequency under natural resonance frequency and this pressure-acting, then by the funtcional relationship P=Δ f/k between pressure and frequency displacement, can try to achieve institute's measuring pressure value, realize pressure survey.
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| CN103196613B (en) * | 2013-03-15 | 2016-02-24 | 西安交通大学 | A kind of high-temperature CMUT pressure sensor and preparation method thereof |
| CN103454345B (en) * | 2013-08-20 | 2016-01-13 | 西安交通大学 | Based on the marine biochemical matter monitoring sensor of CMUT and preparation thereof and measuring method |
| CN104990648B (en) * | 2015-07-28 | 2018-06-01 | 京东方科技集团股份有限公司 | A kind of pressure sensor and its pressure detection method and pressure-detecting device |
| CN105550433B (en) * | 2015-12-10 | 2019-03-05 | 中北大学 | A kind of capacitive micromachined ultrasonic sensor characteristics analysis method |
| CN107421662B (en) * | 2017-06-28 | 2020-11-13 | 重庆芯原微科技有限公司 | Sensitive structure of MEMS capacitive pressure sensor |
| WO2020082256A1 (en) * | 2018-10-24 | 2020-04-30 | 深圳市汇顶科技股份有限公司 | Ultrasonic transducer and manufacturing method therefor |
| US20200156111A1 (en) * | 2018-11-16 | 2020-05-21 | Vermon S.A. | Capacitive micromachined ultrasonic transducer and method of manufacturing the same |
| CN109916554B (en) * | 2019-02-22 | 2021-08-20 | 武汉飞帛丝科技有限公司 | Handheld pressure sensing performance detection equipment |
| CN110361445B (en) * | 2019-07-30 | 2020-10-27 | 西安交通大学 | Multi-parameter high-selectivity CMUTs gas sensor and use and preparation method thereof |
| CN111889341B (en) * | 2020-07-30 | 2021-07-13 | 中国兵器工业集团第二一四研究所苏州研发中心 | Ultrathin flexible silicon-based capacitive micro-machined ultrasonic transducer and processing method |
| CN112326720B (en) * | 2020-10-30 | 2022-05-20 | 河海大学 | Method for extracting thermal expansion coefficient of MEMS multilayer film material |
| CN113154183A (en) * | 2021-03-10 | 2021-07-23 | 北京航空工程技术研究中心 | Detection system in pipeline |
| CN113154267A (en) * | 2021-03-10 | 2021-07-23 | 北京航空工程技术研究中心 | Non-invasive pipe wall clamping sensor for pipeline detection |
| CN114620673B (en) * | 2022-03-18 | 2022-11-15 | 浙江仙声科技有限公司 | Ultrasonic transducer unit and array with CMUT combined with MEMS pressure sensor and manufacturing method |
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| US20060004289A1 (en) * | 2004-06-30 | 2006-01-05 | Wei-Cheng Tian | High sensitivity capacitive micromachined ultrasound transducer |
| US7037746B1 (en) * | 2004-12-27 | 2006-05-02 | General Electric Company | Capacitive micromachined ultrasound transducer fabricated with epitaxial silicon membrane |
| CN100439890C (en) * | 2005-08-25 | 2008-12-03 | 李韫言 | Capacitor type pressure sensor for single chip single crystal silicon micromechanical processing |
| US7839722B2 (en) * | 2007-09-20 | 2010-11-23 | Siemens Medical Solutions Usa, Inc. | Microfabricated acoustic transducer with a multilayer electrode |
| JP4636187B2 (en) * | 2008-04-22 | 2011-02-23 | 株式会社デンソー | Method for manufacturing mechanical quantity sensor and mechanical quantity sensor |
| CN102353610A (en) * | 2011-06-10 | 2012-02-15 | 西安交通大学 | Capacitance micro-machining ultrasonic sensor for measuring density and production method thereof |
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