CN110560349B - Receiving ultrasonic transducer based on Helmholtz resonant cavity and capable of reducing air damping - Google Patents
Receiving ultrasonic transducer based on Helmholtz resonant cavity and capable of reducing air damping Download PDFInfo
- Publication number
- CN110560349B CN110560349B CN201910759760.3A CN201910759760A CN110560349B CN 110560349 B CN110560349 B CN 110560349B CN 201910759760 A CN201910759760 A CN 201910759760A CN 110560349 B CN110560349 B CN 110560349B
- Authority
- CN
- China
- Prior art keywords
- cavity
- ultrasonic transducer
- resonant cavity
- helmholtz
- piezoelectric
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000013016 damping Methods 0.000 title claims abstract description 17
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 33
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 17
- 239000010703 silicon Substances 0.000 claims abstract description 17
- 239000000758 substrate Substances 0.000 claims abstract description 17
- 230000005855 radiation Effects 0.000 claims description 9
- 230000007246 mechanism Effects 0.000 claims description 3
- 238000002604 ultrasonography Methods 0.000 claims 1
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000005530 etching Methods 0.000 description 4
- 238000003475 lamination Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 238000000059 patterning Methods 0.000 description 2
- 230000026683 transduction Effects 0.000 description 2
- 238000010361 transduction Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000006098 acoustic absorber Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 230000010363 phase shift Effects 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 230000002463 transducing effect Effects 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
- B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
- B06B1/0662—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element with an electrode on the sensitive surface
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B2201/00—Indexing scheme associated with B06B1/0207 for details covered by B06B1/0207 but not provided for in any of its subgroups
- B06B2201/50—Application to a particular transducer type
- B06B2201/55—Piezoelectric transducer
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Transducers For Ultrasonic Waves (AREA)
Abstract
The receiving ultrasonic transducer based on the Helmholtz resonant cavity and capable of reducing air damping comprises the Helmholtz resonant cavity positioned at the upper part and the MEMS piezoelectric ultrasonic transducer positioned at the lower part, wherein the Helmholtz resonant cavity and the MEMS piezoelectric ultrasonic transducer are combined through bonding; the MEMS piezoelectric ultrasonic transducer consists of an upper piezoelectric laminated structure and a silicon substrate with a cavity at the lower part, the Helmholtz resonant cavity consists of a silicon structure with a cavity and an upper opening above the piezoelectric laminated structure, the upper part of the silicon structure with the cavity is provided with an upper opening to form a Helmholtz resonant cavity hole, and air in the silicon structure with the cavity forms an air column of the Helmholtz resonant cavity; the middle part of the piezoelectric laminated structure is etched with a hole to form a piezoelectric laminated hole so that the Helmholtz resonant cavity is communicated with the silicon substrate with the cavity, a plurality of radiating grooves are etched on the piezoelectric laminated structure by taking the piezoelectric laminated hole as the center, the piezoelectric laminated structure among the plurality of radiating grooves forms a cantilever beam, one end, connected with the piezoelectric laminated structure, of the cantilever beam is a fixed end, and the other end, connected with the piezoelectric laminated hole, of the cantilever beam is a free end.
Description
Technical Field
The invention belongs to the technical field of MEMS (micro-electromechanical systems) ultrasonic transducers, and relates to a receiving ultrasonic transducer based on a Helmholtz resonant cavity and capable of reducing air damping.
Background
An ultrasonic transducer is a transducing element that can be used to both transmit and receive ultrasonic waves. When the transducer works in a transmitting mode, electric energy is converted into vibration of the transducer through electrostatic force or inverse piezoelectric effect so as to radiate sound waves outwards; when the transducer works in a receiving mode, sound pressure acts on the surface of the transducer to enable the transducer to vibrate, and the transducer converts the vibration into an electric signal. At present, the most widely used ultrasonic sensor is mainly based on a piezoelectric transducer, the piezoelectric transducer mainly utilizes a thickness vibration mode of piezoelectric ceramics to generate ultrasonic waves, and because the resonant frequency of the thickness mode is only related to the thickness of the transducer, the ultrasonic transducers with different resonant frequencies are difficult to manufacture on the same plane. When the high-frequency-resistant high-frequency-. The ultrasonic transducer (MEMS ultrasonic transducer) manufactured by the micro-processing technology vibrates in a bending mode, has a vibrating film with lower rigidity, has lower acoustic impedance, and can be better coupled with gas and liquid. And the resonant frequency is controlled by the in-plane dimension, so that the requirement on the machining precision is low. With the gradual maturity of the MEMS ultrasonic transducer technology, the technology of the ultrasonic sensor tends to turn to the MEMS ultrasonic transducer because of its advantages of high performance, low cost and easy realization of mass production. The MEMS ultrasonic transducer mainly comprises two capacitance type (cMUT) and piezoelectric type (pMUT), the sensitivity of the pMUT is slightly lower than that of the cMUT, but the cMUT needs to provide bias voltage and a tiny air gap is arranged between capacitance plates, adhesion is easily formed, and the pMUT has the advantages of simple structure and high transduction efficiency of transduction materials, but the manufacture of the pMUT is more complex.
Patent CN109196671A discloses a piezoelectric micromachined ultrasonic transducer (pMUT) that reduces acoustic diffraction by adding a high acoustic velocity material to the transducer to generate high frequencies. The PMUT has a low quality factor, providing shorter start-up and shut-down times, to enable better suppression of parasitic reflections through time-gating. Patent CN107394036A discloses an electrode configuration of pMUT and pMUT transducer arrays, which makes the transducer have different modes of action by using a dual electrode or multiple electrodes in the upper electrode, by applying the same or different electrical signals to the different electrodes. Patent CN106660074A discloses a piezoelectric ultrasonic transducer and process, which uses an anchoring structure and a mechanical layer to form a cavity, adjusts the position of the central axis of the stacked layers through the mechanical layer, thereby allowing the stacked layers to vibrate in bending, and adjusts the parameters of resonance frequency, quality factor Q, etc. through the use of a recess. Overall, the current pMUT improvements are mainly directed to the electrode shape, the addition of materials to the outside, and the like, but have limited effects on improving pMUT performance. And because the operating environment of the pMUT is air or half air and half vacuum, the pMUT is subjected to large air damping when vibrating, resulting in a low signal when receiving sound.
Helmholtz resonators are a passive acoustic device that can be used for amplification, sound absorption. The Helmholtz resonator can be excited by an external sound field and consumes its energy as an acoustic absorber. The vibration in the cavity can emit sound waves through the short pipe to strengthen the external sound field. This type of transducer, known as a PSRC (piezoelectric-sound-resonance cavity), can be used to amplify the acoustic waves emitted by pmuts, by exploiting the characteristic that Helmholtz resonators can amplify, absorb sound and have a very sharp selectivity, thus improving their energy conversion efficiency. When PSRC emits sound waves, the vibration of pMUT causes the change of the cavity volume of the Helmholtz resonant cavity, so that air at the orifice flows in and out to generate flow speed; meanwhile, when the resonance frequency of the pMUT is consistent with that of the Helmholtz resonant cavity, the resonance of the two structures enables a high-pressure area to be generated in the cavity, and the pressure difference between the cavity and the outside atmosphere enables a larger flow speed to be generated at the orifice; at this time, the air flow at the orifice impacts the orifice, and the sound wave is radiated outwards by the vortex sound conversion principle. When PSRC's received the sound wave, Helmholtz resonator is as the acoustic load, thereby the sound wave propagation arouses in the cavity medium resonance to consume resonant frequency's sound wave energy to arouse the internal acoustic pressure increase of cavity to the drill way, and the acoustic pressure effect makes its vibration on the transducer surface, and at this moment, because pMUT resonant frequency is unanimous with Helmholtz resonant cavity resonant frequency, can increase the amplitude of transducer vibration to improve the intensity of the electrical signal that the transducer will vibrate the conversion.
Patent CN202818594U discloses a piezoelectric sounder structure for increasing sound pressure value, and its patent provides a sounder structure for increasing sound pressure value without changing volume of sounder. Patent CN108831432A discloses a broadband air noise energy collecting surface material, which controls the phase shift occurring at the resonance frequency of the Helmholtz resonant cavity, and constructs the coupling resonance with the opposite phase in the structure, so as to realize broadband efficient sound and electric energy collection. Patent CN106796473A discloses a piezoelectric acoustic wave resonator based sensor that works with the resonant frequency of a helmholtz resonator array overlaid on a piezoelectric transducer array. When a fingerprint is pressed against the cavity, an increase in the resonant frequency of the cavity and a decrease in the quality factor Q are caused. The fingerprint is identified by detecting these changes.
Generally speaking, when the PSRC works in the condition that the resonance frequencies of the pMUT and the Helmholtz resonant cavity are consistent, the Helmholtz resonant cavity resonates at this time, the sound pressure in the cavity is very high, and meanwhile, because the frequency is also the pMUT resonance frequency, the resonance of the two structures can cause the electric signals received by the receiving transducer to be greatly increased, so that the performance of the receiving ultrasonic transducer is improved.
Disclosure of Invention
In order to improve the performance of the receiving ultrasonic transducer and reduce the air damping to which the pMUT vibrates, the invention provides the receiving ultrasonic transducer based on the Helmholtz resonant cavity and reducing the air damping.
In order to achieve the purpose, the invention adopts the technical scheme that:
a receiving ultrasonic transducer based on Helmholtz resonant cavity and capable of reducing air damping comprises a Helmholtz resonant cavity and a MEMS piezoelectric ultrasonic transducer, wherein the Helmholtz resonant cavity is positioned at the upper part, the MEMS piezoelectric ultrasonic transducer is positioned at the lower part, and the Helmholtz resonant cavity and the MEMS piezoelectric ultrasonic transducer are bonded;
the MEMS piezoelectric ultrasonic transducer comprises an upper piezoelectric laminated structure and a silicon substrate with a cavity at the lower part, the Helmholtz resonant cavity comprises a silicon structure with a cavity and an upper opening above the piezoelectric laminated structure, the upper part of the silicon structure with the cavity is provided with an upper opening to form a Helmholtz resonant cavity hole, and air in the silicon structure with the cavity forms an air column of the Helmholtz resonant cavity;
piezoelectricity laminated structure middle part sculpture has the hole to form piezoelectricity stromatolite hole and makes Helmholtz resonant cavity with take cavity silicon substrate intercommunication, and piezoelectricity laminated structure is last with piezoelectricity stromatolite hole has a plurality of radiation grooves for the central sculpture, piezoelectricity laminated structure between a plurality of radiation grooves forms cantilever beam, the cantilever beam links to each other one end with piezoelectricity laminated structure and is the stiff end, with the continuous one end of piezoelectricity stromatolite hole is the free end.
Furthermore, a flexible spring is arranged between the free ends of two adjacent cantilever beams, so that the adjacent cantilever beams are prevented from crosstalk when vibrating, and the deformation of the cantilever beams is inconsistent.
Furthermore, the MEMS piezoelectric ultrasonic transducer adopts a traditional sandwich structure or a bimorph structure and is used for receiving sound waves in a cavity when the Helmholtz resonant cavity resonates;
when the MEMS piezoelectric ultrasonic sensor adopts a traditional sandwich structure, an upper electrode, a piezoelectric layer, a lower electrode, a CSOI substrate and a bulk silicon substrate with a cavity are arranged from top to bottom in sequence;
when the MEMS piezoelectric ultrasonic transducer adopts a bimorph structure, an upper electrode, a piezoelectric layer, a middle electrode, a piezoelectric layer, a lower electrode and a silicon substrate with a cavity are arranged from top to bottom in sequence.
Preferably, the upper opening is not positioned at the upper part of the silicon structure with the cavity, and the upper opening is circular or polygonal in shape.
Preferably, the cross section of the Helmholtz resonant cavity is a circular or polygonal mechanism, and the shape of the piezoelectric stack hole is a circle or a polygon.
Further, the resonance frequency of the Helmholtz resonant cavity is the same as or different from the resonance frequency of the MEMS piezoelectric ultrasonic transducer.
The invention has the beneficial effects that:
1. the invention combines the MEMS piezoelectric ultrasonic transducer with a Helmholtz resonant cavity. When the MEMS piezoelectric ultrasonic transducer receives sound waves, when the frequency of the sound waves is consistent with the resonant frequency of the Helmholtz resonant cavity, the sound waves are transmitted to the hole opening to cause medium in the cavity to resonate and consume the sound wave energy of the resonant frequency, so that the sound pressure in the cavity is increased, and the sound pressure acts on the surface of the transducer to vibrate. At this time, if the resonance frequency of the MEMS piezoelectric ultrasonic transducer is consistent with the resonance frequency of the Helmholtz resonant cavity, the vibration amplitude of the transducer is increased; if the resonance frequency of the MEMS piezoelectric ultrasonic transducer is not consistent with that of the Helmholtz resonant cavity, the sound pressure applied to the MEMS piezoelectric ultrasonic transducer is large due to the amplification of the sound pressure by the Helmholtz resonant cavity, and a large amplitude can still be generated. Overall, the acoustoelectric conversion efficiency and sensitivity of the ultrasonic transducer are increased.
2. According to the invention, the piezoelectric laminated structure of the MEMS piezoelectric ultrasonic transducer is subjected to graphical processing, holes are etched in the laminated structure, and grooves are etched around the laminated structure, so that air on the upper interface and the lower interface can circulate through the holes and the grooves when the MEMS piezoelectric ultrasonic transducer vibrates, and thus the air damping of the MEMS piezoelectric ultrasonic transducer caused by vibration is reduced. Meanwhile, a flexible spring structure can be added between the free ends of the cantilever beams, and the two cantilever beams form a group, so that the adjacent cantilever beams can be prevented from crosstalk in vibration, and the deformation of the cantilever beams is inconsistent.
Drawings
FIG. 1 is a cross-sectional view, a top view of a Helmholtz resonant cavity, and a top view of a pMUT of an embodiment of the invention in a sandwich configuration;
FIG. 2 is a cross-sectional view, a top view of a Helmholtz resonant cavity, and a top view of a pMUT of an embodiment of the present invention using a bimorph structure;
FIG. 3 is a cross-sectional view, a top view of a Helmholtz resonant cavity, and a top view of a pMUT of an embodiment of the present invention incorporating a compliant spring based sandwich structure;
FIG. 4 is a front view of a pMUT employing a sandwich configuration;
FIGS. 5 to 10 are flow charts of processing according to embodiments of the present invention
The parts in the drawings are numbered as follows:
1 sandwich structure pMUT, 1-1CSOI wafer, 1-2 bottom electrodes, 1-3 piezoelectric layers, 1-4 top electrodes, 1-5SiO2The device comprises an insulating layer, 1-6 gold electrodes, 1-7 flexible springs, 1-8 piezoelectric lamination holes, 1-9 radiation grooves and 1-10 cantilever beams; 1-11 free ends, 1-12 fixed ends, 2Helmholtz resonant cavities, and 3 twin-wafer structure pMUT; 4 with cavity silicon structure, 4-1 with opening on top, 5 with cavity silicon substrate.
It should be understood that: the MEMS piezoelectric ultrasonic transducer is called a piezo-electric micro-ultrasonic transducer in english, and is called as follows: pMUT.
Detailed Description
The invention is further described with reference to the following drawings and specific embodiments.
Referring to fig. 1, 2, 3 and 4, a receiving ultrasonic transducer based on a Helmholtz resonant cavity and reducing air damping comprises a Helmholtz resonant cavity 2 at the upper part and a MEMS piezoelectric ultrasonic transducer at the lower part, wherein the Helmholtz resonant cavity 2 and the MEMS piezoelectric ultrasonic transducer are bonded. The MEMS piezoelectric ultrasonic transducer consists of an upper piezoelectric laminated structure and a bottom silicon substrate 5 with a cavity.
The Helmholtz resonant cavity 2 is formed by bonding a cavity-containing silicon structure 4 with an upper opening 4-1 above a piezoelectric laminated structure, the cavity-containing silicon structure 4 is a semi-enclosed structure, the opening is downward and is bonded with the piezoelectric laminated structure to form the Helmholtz resonant cavity 2, a Helmholtz resonant cavity hole is formed in the upper opening 4-1 of the cavity-containing silicon structure 4, air in the Helmholtz resonant cavity hole forms an air column of the Helmholtz resonant cavity 2, the position of the upper opening 4-1 on the cavity-containing silicon structure 4 is not limited, the upper opening 4-1 is only required to be positioned at an upper top cover of the semi-enclosed structure, and preferably the upper opening 4-1 is circular or polygonal.
The resonance frequency of the Helmholtz resonant cavity 2 is:
wherein c is the sound velocity in the medium, S is the open pore area, t is the open pore height, d is the open pore diameter, and V is the volume of the cavity.
The MEMS piezoelectric ultrasonic transducer is characterized in that a piezoelectric laminated structure of the MEMS piezoelectric ultrasonic transducer is subjected to patterning treatment, then holes are etched in the middle of the MEMS piezoelectric ultrasonic transducer to form piezoelectric laminated holes 1-8, so that the Helmholtz resonant cavity 2 is communicated with the silicon substrate 5 with the cavity, a plurality of radiation grooves 1-9 are etched on the piezoelectric laminated structure by taking the piezoelectric laminated holes 1-8 as centers, cantilever beams 1-10 are formed by the piezoelectric laminated structures among the radiation grooves 1-9, the cantilever beams 1-10 are of fan-shaped or trapezoid structures, the fixed ends 1-12 are connected with the piezoelectric laminated structures at the ends of the cantilever beams 1-10, and the free ends 1-11 are connected with the piezoelectric laminated holes 1-8 at the ends of the cantilever beams. The holes 1-8 of the piezoelectric lamination and the plurality of radial grooves 1-9 are etched, so that air on the upper interface and the lower interface can flow through the holes and the grooves when the MEMS piezoelectric ultrasonic transducer vibrates, and the air damping of the vibration of the MEMS piezoelectric ultrasonic transducer is reduced.
A flexible spring is arranged between the free ends 1-11 of the two adjacent cantilever beams 1-10, the flexible spring is formed when the radiation grooves 1-9 and the piezoelectric lamination holes 1-8 are etched, a certain distance is reserved between the end part of the radiation groove 1-9 and the piezoelectric lamination holes 1-8 to form the flexible spring, and the flexible spring plays a role in connecting the two cantilever beams 1-10 so as to reduce the inconsistent deformation of the cantilever beams 1-10 caused by signal crosstalk caused by the asynchronization of the cantilever beams 1-10.
As shown in fig. 1, 2 and 3, the MEMS piezoelectric ultrasonic transducer adopts a conventional sandwich structure or a bimorph structure, and is configured to receive acoustic waves in a cavity when the Helmholtz resonant cavity 2 resonates; when the MEMS piezoelectric ultrasonic sensor adopts a traditional sandwich structure, namely a sandwich structure pMUT1, an upper electrode, a piezoelectric layer, a lower electrode, a CSOI wafer 1-1 and a bulk silicon substrate 5 with a cavity are arranged from top to bottom in sequence; when the MEMS piezoelectric ultrasonic transducer adopts a bimorph structure, namely a bimorph structure pMUT3, an upper electrode, a piezoelectric layer, a middle electrode, the piezoelectric layer, a lower electrode and a silicon substrate 5 with a cavity are arranged from top to bottom in sequence.
Preferably, the cross section of the Helmholtz resonant cavity 2 is a circular or polygonal mechanism, and the shapes of the piezoelectric laminated holes 1-8 are circular or polygonal.
Further, the resonance frequency of the Helmholtz resonator 2 is the same as or different from the resonance frequency of the MEMS piezoelectric ultrasonic transducer. When the ultrasonic wave is received, when the frequency of the sound wave is consistent with the resonant frequency of the Helmholtz resonant cavity 2, the sound wave is transmitted to the hole opening to cause the medium in the cavity to resonate and consume the sound wave energy of the resonant frequency, so that the sound pressure in the cavity is increased, and the sound pressure acts on the surface of the MEMS transducer to enable the MEMS transducer to vibrate. At this time, if the resonance frequency of the MEMS piezoelectric ultrasonic transducer is consistent with that of the Helmholtz resonant cavity 2, the vibration amplitude of the transducer vibration will be increased; if the resonant frequency of the MEMS piezoelectric ultrasonic transducer is not consistent with that of the Helmholtz resonant cavity 2, but due to the amplification of the acoustic pressure by the Helmholtz resonant cavity 2, the acoustic pressure acting on the MEMS piezoelectric ultrasonic transducer is large, and a large amplitude can still be generated. Overall, the acoustoelectric conversion efficiency and sensitivity of the ultrasonic transducer are increased.
Please refer to fig. 5 to 10, which show the following steps in detail for the preparation process of the ultrasonic transducer provided by the present invention:
s110, performing CMP on a CSOI wafer 1-1, and polishing the silicon layer to a designed size;
s120, sequentially depositing a bottom electrode 1-2, a piezoelectric layer 1-3 and a top electrode 1-4 on the polished CSOI wafer 1-1, and carrying out patterning treatment on the top electrode 1-4;
s130 depositing a layer of SiO on the wafer with the deposited laminated structure21-5 insulating layers, and then leading out 1-6 gold electrodes;
s140, performing graphical processing, namely etching the piezoelectric laminated holes 1-8 at the center and etching the radial grooves 1-9 at the periphery to form flexible springs 1-7;
s150, etching a Helmholtz resonant cavity 2 on a silicon wafer;
s160, etching an upper opening 4-1 on the Helmholtz resonant cavity 2 to form a Helmholtz resonant cavity hole;
s170 bonding the Helmholtz resonator 2 to the MEMS piezoelectric ultrasonic transducer 1.
Claims (6)
1. A receiving ultrasonic transducer based on a Helmholtz resonator and with reduced air damping, characterized by: the MEMS piezoelectric ultrasonic transducer comprises a Helmholtz resonant cavity positioned at the upper part and an MEMS piezoelectric ultrasonic transducer positioned at the lower part, wherein the Helmholtz resonant cavity and the MEMS piezoelectric ultrasonic transducer are combined through bonding;
the MEMS piezoelectric ultrasonic transducer consists of an upper piezoelectric laminated structure and a silicon substrate with a cavity at the lower part, the Helmholtz resonant cavity consists of a silicon structure with a cavity and an upper opening above the piezoelectric laminated structure, the upper part of the silicon structure with the cavity is provided with an upper opening to form a Helmholtz resonant cavity hole, and air in the silicon structure with the cavity forms an air column of the Helmholtz resonant cavity;
piezoelectricity laminated structure middle part sculpture has the hole to form piezoelectricity stromatolite hole and makes Helmholtz resonant cavity with take cavity silicon substrate intercommunication, and piezoelectricity laminated structure is last with piezoelectricity stromatolite hole has a plurality of radiation grooves for the central sculpture, piezoelectricity laminated structure between a plurality of radiation grooves forms the cantilever beam, the cantilever beam links to each other one end with piezoelectricity laminated structure and is the stiff end, with the one end that piezoelectricity stromatolite hole links to each other is the free end.
2. A receiving ultrasonic transducer based on Helmholtz resonator and reduced air damping according to claim 1, wherein: and a flexible spring is arranged between the free ends of two adjacent cantilever beams, so that the adjacent cantilever beams are prevented from crosstalk in vibration, and the deformation of the cantilever beams is inconsistent.
3. A Helmholtz-based resonant cavity reduced air damping receiving ultrasonic transducer according to claim 1 or 2, characterized in that: the MEMS piezoelectric ultrasonic transducer adopts a traditional sandwich structure or a bimorph structure and is used for receiving sound waves in a resonant cavity of the Helmholtz resonant cavity;
when the MEMS piezoelectric ultrasonic sensor adopts a traditional sandwich structure, an upper electrode, a piezoelectric layer, a lower electrode, a CSOI substrate or a bulk silicon substrate with a cavity are arranged from top to bottom in sequence;
when the MEMS piezoelectric ultrasonic transducer adopts a bimorph structure, an upper electrode, a piezoelectric layer, a middle electrode, a piezoelectric layer, a lower electrode and a silicon substrate with a cavity are arranged from top to bottom in sequence.
4. A Helmholtz-resonator-based receive ultrasonic transducer with reduced air damping according to claim 3, wherein: the upper opening is indefinite at the upper part of the silicon structure with the cavity, and the upper opening is circular or polygonal.
5. A Helmholtz-resonator-based receive ultrasound transducer with reduced air damping according to claim 4, characterized in that: the cross section of the Helmholtz resonant cavity is a circular or polygonal mechanism, and the shape of the piezoelectric laminated hole is circular or polygonal.
6. A Helmholtz-resonator-based receive ultrasonic transducer with reduced air damping in accordance with claim 5, wherein: the resonance frequency of the Helmholtz resonant cavity is the same as or different from the resonance frequency of the MEMS piezoelectric ultrasonic transducer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910759760.3A CN110560349B (en) | 2019-08-16 | 2019-08-16 | Receiving ultrasonic transducer based on Helmholtz resonant cavity and capable of reducing air damping |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910759760.3A CN110560349B (en) | 2019-08-16 | 2019-08-16 | Receiving ultrasonic transducer based on Helmholtz resonant cavity and capable of reducing air damping |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110560349A CN110560349A (en) | 2019-12-13 |
| CN110560349B true CN110560349B (en) | 2020-08-25 |
Family
ID=68775588
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910759760.3A Active CN110560349B (en) | 2019-08-16 | 2019-08-16 | Receiving ultrasonic transducer based on Helmholtz resonant cavity and capable of reducing air damping |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110560349B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113630686A (en) * | 2021-08-13 | 2021-11-09 | 南京工程学院 | High-strength Helmholtz sound source design method based on pattern recognition |
| CN114112010A (en) * | 2022-01-26 | 2022-03-01 | 青岛国数信息科技有限公司 | Acoustic measurement unit and device for ultra-low frequency underwater acoustic signal detection |
| CN115376479A (en) * | 2022-04-07 | 2022-11-22 | 同济大学 | Sound absorption and bearing integrated structure based on perforated hollow rod and preparation method thereof |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011114628A1 (en) * | 2010-03-18 | 2011-09-22 | パナソニック株式会社 | Mems element, and manufacturing method of mems element |
| US9299671B2 (en) * | 2013-10-15 | 2016-03-29 | Invensense, Inc. | Integrated CMOS back cavity acoustic transducer and the method of producing the same |
| CN103796120A (en) * | 2013-10-28 | 2014-05-14 | 广州市番禺奥迪威电子有限公司 | Piezoelectric receiver |
| CN203708424U (en) * | 2013-12-30 | 2014-07-09 | 瑞声声学科技(深圳)有限公司 | Microphone |
| US9902152B2 (en) * | 2016-06-30 | 2018-02-27 | Intel Corporation | Piezoelectric package-integrated synthetic jet devices |
| CN208987176U (en) * | 2018-10-11 | 2019-06-14 | 东莞希越电子有限公司 | A kind of piezoelectric membrane microphone structure |
| CN110052391B (en) * | 2019-05-28 | 2023-06-16 | 浙江大学 | Micromechanical piezoelectric ultrasonic transducer coupled by double resonance modes |
-
2019
- 2019-08-16 CN CN201910759760.3A patent/CN110560349B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN110560349A (en) | 2019-12-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110560350B (en) | Receiving ultrasonic transducer based on Helmholtz resonant cavity | |
| CN110560348B (en) | MEMS piezoelectric ultrasonic transducer with hole array Helmholtz resonant cavity | |
| CN111001553B (en) | Tunable ultrasonic sensor array | |
| CN110560349B (en) | Receiving ultrasonic transducer based on Helmholtz resonant cavity and capable of reducing air damping | |
| JP6360487B2 (en) | Micromachined ultrasonic transducer array with multiple harmonic modes | |
| CN110052391B (en) | Micromechanical piezoelectric ultrasonic transducer coupled by double resonance modes | |
| CN110560352B (en) | Frequency-adjustable ultrasonic sensor array based on Helmholtz resonant cavity | |
| CN110681559B (en) | MEMS piezoelectric ultrasonic transducer with Helmholtz resonant cavity | |
| CN111314829B (en) | MEMS piezoelectric ultrasonic transducer with sound tube | |
| JP2015521409A (en) | Ultra-wide bandwidth converter with double electrodes | |
| JP2009260723A (en) | Transducer | |
| CN112718437B (en) | Piezoelectric micromechanical ultrasonic transducer based on multi-diaphragm coupling | |
| CN110560351B (en) | Frequency-adjustable sound wave receiving device based on Helmholtz resonant cavity | |
| CN112871613A (en) | Piezoelectric micromachined ultrasonic transducer with support posts | |
| CN110944274B (en) | Tunable MEMS piezoelectric transducer with mass load based on Pitton-mode | |
| CN115532572A (en) | Multi-frequency piezoelectric micro-mechanical ultrasonic transducer and preparation method thereof | |
| JP3416648B2 (en) | Acoustic transducer | |
| CN111054615B (en) | MEMS piezoelectric ultrasonic transducer with horn structure | |
| CN110681560B (en) | MEMS ultrasonic positioning sensor with Helmholtz resonant cavity | |
| CN116723754A (en) | Piezoelectric micromechanical ultrasonic transducer and manufacturing method thereof | |
| CN116764922A (en) | Micro-mechanical ultrasonic transducer driven by planar double-piezoelectric material | |
| CN108311361A (en) | Micro electronmechanical piezoelectric supersonic wave transducer with the modality-specific vibration shape | |
| JP2012119831A (en) | Ultrasonic vibrator unit and ultrasonic probe | |
| JP2012175507A (en) | Ultrasonic vibrator | |
| CN219723596U (en) | Ultrasonic transducer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20220407 Address after: 315832 e2025, zone a, Room 401, building 1, No. 88, Meishan Qixing Road, Beilun District, Ningbo, Zhejiang Province Patentee after: Ningbo Huazhang enterprise management partnership (L.P.) Address before: 430072 Hubei Province, Wuhan city Wuchang District of Wuhan University Luojiashan Patentee before: WUHAN University |
|
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20220830 Address after: No.01, 4th floor, building D7, phase 3, Wuhan Software New Town, No.9 Huacheng Avenue, Donghu New Technology Development Zone, Wuhan City, Hubei Province, 430000 Patentee after: Wuhan Minsheng New Technology Co.,Ltd. Address before: 315832 e2025, zone a, Room 401, building 1, No. 88, Meishan Qixing Road, Beilun District, Ningbo, Zhejiang Province Patentee before: Ningbo Huazhang enterprise management partnership (L.P.) |
|
| TR01 | Transfer of patent right |