CN110152965A - A kind of double frequency piezoelectric type micromachined ultrasonic transducer and preparation method thereof - Google Patents
A kind of double frequency piezoelectric type micromachined ultrasonic transducer and preparation method thereof Download PDFInfo
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- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 229910052751 metal Inorganic materials 0.000 claims abstract description 152
- 239000002184 metal Substances 0.000 claims abstract description 152
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 71
- 239000010703 silicon Substances 0.000 claims abstract description 71
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 71
- 239000010409 thin film Substances 0.000 claims abstract description 62
- 239000000758 substrate Substances 0.000 claims abstract description 32
- 238000000034 method Methods 0.000 claims abstract description 22
- 239000010410 layer Substances 0.000 claims description 211
- 239000010408 film Substances 0.000 claims description 49
- 230000008021 deposition Effects 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 18
- 238000005530 etching Methods 0.000 claims description 11
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 10
- 239000010931 gold Substances 0.000 claims description 10
- 229910052737 gold Inorganic materials 0.000 claims description 10
- 239000000126 substance Substances 0.000 claims description 10
- 238000001039 wet etching Methods 0.000 claims description 10
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 9
- 238000001259 photo etching Methods 0.000 claims description 8
- 238000005253 cladding Methods 0.000 claims description 6
- 239000010936 titanium Substances 0.000 claims description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 4
- 239000004411 aluminium Substances 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 239000011651 chromium Substances 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000010949 copper Substances 0.000 claims description 4
- 229910052697 platinum Inorganic materials 0.000 claims description 4
- 239000002356 single layer Substances 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 240000007594 Oryza sativa Species 0.000 claims description 2
- 235000007164 Oryza sativa Nutrition 0.000 claims description 2
- 235000009566 rice Nutrition 0.000 claims description 2
- 230000005611 electricity Effects 0.000 claims 3
- 230000008569 process Effects 0.000 abstract description 4
- 238000000151 deposition Methods 0.000 description 12
- 238000002604 ultrasonography Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 7
- 238000006073 displacement reaction Methods 0.000 description 7
- 238000003384 imaging method Methods 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000012528 membrane Substances 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 239000002305 electric material Substances 0.000 description 1
- 238000004070 electrodeposition Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000001727 in vivo Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
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- 238000010895 photoacoustic effect Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000002560 therapeutic procedure Methods 0.000 description 1
- 230000002463 transducing effect Effects 0.000 description 1
- 230000026683 transduction Effects 0.000 description 1
- 238000010361 transduction Methods 0.000 description 1
Classifications
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- 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
- B06B1/0607—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 multiple elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
- B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/01—Manufacture or treatment
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/01—Manufacture or treatment
- H10N30/06—Forming electrodes or interconnections, e.g. leads or terminals
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/87—Electrodes or interconnections, e.g. leads or terminals
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- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Mechanical Engineering (AREA)
- Computer Hardware Design (AREA)
- Transducers For Ultrasonic Waves (AREA)
Abstract
The invention discloses a kind of double frequency piezoelectric type micromachined ultrasonic transducers and preparation method thereof.There is presently no the double frequency piezoelectric type micromachined ultrasonic transducers based on single vibrating diaphragm.The present invention from top to bottom successively includes electrode of metal layer, piezoelectric thin film layer, lower metal electrode layer, silicon device layer, buried oxide layer, silicon substrate layer.Microcavity is provided in buried oxide layer and silicon substrate layer.Piezoelectric thin film layer includes the square frame being generally aligned in the same plane and the circular piece that is arranged in outline border.Electrode of metal layer includes being generally aligned in the same plane non-touching two circular ring shape top electrodes；Lower metal electrode layer includes being generally aligned in the same plane electrode under non-touching two circular ring shapes.The circular ring metal plate shape of the upper and lower electrode of outer ring and the upper and lower electrode of inner ring is identical with size, and position is corresponding.The present invention can be simultaneously emitted by the broad band ultrasonic of two kinds of different center frequencies on single vibrating diaphragm, and simple process is conducive to Wave beam forming, be suitable for double frequency-band on piece ultrasonic system.
Description
Technical field
The invention belongs to field of micro electromechanical technology, are related to a kind of ultrasonic transducer, specifically a kind of double frequency piezoelectric type microcomputer
Tool ultrasonic transducer and preparation method thereof.
Background technique
Ultrasonic technique industrial detection and biomedicine in be widely used, such as ultrasonic inspection, ultrasound-driven, medicine at
Picture, ultrasonic therapy, particle manipulation etc..Ultrasonic wave can by such as piezoelectric effect, magnetostriction and optoacoustic effect equal excitation,
In, latter ultrasound is most common.Conventional piezoelectric ultrasonic transducer has sandwich structure, i.e. a layer of piezo-electric material is clipped in
Between two metal electrodes.In addition, adding matching layer and back sheet respectively in front-end and back-end, one is just constituted typically
D33 vibration mode ultrasonic transducer.The working frequency of this energy converter directly depends on piezoelectric material layer thickness, therefore, transducing
The geometry and structure of device are extremely restricted.For example, the resonant frequency of PZT thin film is at least several hundred under d33 mode
Megahertz.However, frequency is excessively high to be caused to decay too fast, ultrasonic penetration depth is very shallow, while matching layer is difficult accurately to make, it is difficult to
It is imaged applied to in-vivo tissue.
The birth of micromachined ultrasonic transducer overcomes the above problem.Micromachined ultrasonic transducer is generally divided into two classes, and one
Kind is the capacitive micromachined ultrasonic transducer based on electrostatic force, and another kind is the piezoelectric type micromechanics based on piezoelectric activity
Ultrasonic transducer, their typical vibration modes are all d31 modes.In work, vibrating membrane bends deformation, to generate
Ultrasonic wave.The d33 vibration mode of this and through-thickness in conventional ultrasound transducer has essential distinction.It is super with piezoelectric type micromechanics
For sonic transducer, the deflection of vibrating membrane is therefore the ultrasonic transduction caused by the transverse strain that is generated as piezoelectric effect
The resonance frequency of device is not directly dependent on the thickness of piezoelectric material, but with the shape of vibrating membrane, size, boundary constraint, stress
And the correlations such as mechanical stiffness.
Currently, either conventional ultrasound transducer or micromachined ultrasonic transducer, all work under single band, issue
Or absorb single-frequency ultrasound.In order to improve imaging resolution or carry out harmonic imaging, it is super to improve that researchers have done a large amount of effort
The bandwidth of sonic transducer.Such as in Second Harmonic Imaging, if fundamental frequency is 2MHz, second harmonic frequency is 4MHz, then
Needing a centre frequency is the traditional single-frequency ultrasonic transducer of 3MHz, bandwidth close to 100%.However, all due to ultrasonic device
There are certain physics limit, this method is difficult to expand to higher hamonic wave imaging.It is answered to meet such as higher hamonic wave imaging
With requiring, some researchers begin trying to combine two or more single-frequency ultrasonic transducers, and this method is to a certain extent
Alleviate the needs of problems of higher hamonic wave imaging.But also bring new problem.For example, the assembling of conventional ultrasound transducer
Process is extremely complex, can not scale of mass production, although assembling micromachined ultrasonic transducer relatively be easy, however, due to two
The ultrasound of kind frequency comes from different vibrating diaphragms, and the performance of Wave beam forming will receive certain influence.
Summary of the invention
The object of the present invention is to provide a kind of double frequency piezoelectric type micromachined ultrasonic transducers, while providing the double frequency piezoelectric type
The preparation method of micromachined ultrasonic transducer.
Double frequency piezoelectric type micromachined ultrasonic transducer of the invention, generally cylinder, the diameter of regular polygon bottom surface are 20
~20000 microns；Include successively from top to bottom electrode of metal layer, piezoelectric thin film layer, lower metal electrode layer, silicon device layer, bury
Oxygen layer, silicon substrate layer.
The center of buried oxide layer and silicon substrate layer is provided with microcavity；The circle that the microcavity is 10~10000 microns of diameter
Column is prismatic, is arranged through buried oxide layer, and silicon device layer is adhered in buried oxide layer, by the top closed of microcavity；The silicon device
Layer is with a thickness of 0.1~10 micron, and buried oxide layer is with a thickness of 0.5~5 micron, and silicon substrate layer is with a thickness of 200~800 microns.
The piezoelectric thin film layer is arranged between electrode of metal layer and lower metal electrode layer, including is generally aligned in the same plane
Regular polygon outline border and the circular piece that is arranged in outline border, circular piece be arranged concentrically with microcavity, the outer of circular piece and outline border
The middle position on each side connects, and two vertex of outline border are connect with the outer of circular piece by strip piece respectively.
The electrode of metal layer includes being generally aligned in the same plane non-touching two circular ring shape top electrodes, respectively outer
Ring top electrode and inner ring top electrode.Outer ring top electrode includes the bullion piece being wholely set and the circular ring metal with opening
Piece, one end of bullion piece are connected to circular ring metal piece outer, and the other end extends to the centre on outline border one side of piezoelectric thin film layer
Position.Inner ring top electrode includes the bullion piece being wholely set and complete circular ring metal piece, and bullion piece one terminates
To circular ring metal piece outer, the other end pass through the opening extend to piezoelectric thin film layer outline border a vertex, and with
One strip piece position of piezoelectric thin film layer is corresponding.The circular ring metal piece of outer ring top electrode and inner ring top electrode is same with microcavity
Heart setting, the outer diameter of the circular ring metal piece of outer ring top electrode are less than the internal diameter of microcavity.
The lower metal electrode layer includes being generally aligned in the same plane electrode under non-touching two circular ring shapes, respectively outer
Electrode under electrode and inner ring under ring.Electrode includes the bullion piece being wholely set and the circular ring metal with opening under outer ring
Piece, one end of bullion piece are connected to circular ring metal piece outer, and the other end extends in the outline border another side of piezoelectric thin film layer
Between position.Electrode includes the bullion piece being wholely set and complete circular ring metal piece, bullion piece one end under inner ring
It is connected to circular ring metal piece outer, the other end passes through another vertex that the opening extends to the outline border of piezoelectric thin film layer,
And it is corresponding with another strip piece position of piezoelectric thin film layer.Under outer ring under electrode and inner ring the circular ring metal piece of electrode with
Microcavity is arranged concentrically, and the outer diameter of the circular ring metal piece of electrode is less than the internal diameter of microcavity under outer ring.
The outer ring top electrode is identical with size with the circular ring metal plate shape of electrode under outer ring, and position is corresponding；Institute
The outer ring top electrode stated is identical with size with the bullion plate shape of electrode under outer ring, extends respectively to the outer of piezoelectric thin film layer
The middle position on frame difference both sides.
The inner ring top electrode is identical with size with the circular ring metal plate shape of electrode under inner ring, and position is corresponding；It is interior
Ring top electrode is identical with size with the bullion plate shape of electrode under inner ring, and the outline border for extending respectively to thin film layer is different
Two vertex, two strip pieces of thin film layer bullion piece position pair with electrode under inner ring top electrode and inner ring respectively
It answers.
The exradius R of the circular ring metal piece of electrode under the inner ring top electrode and inner ringiWith inner circle radius riRatio
Example is 5:2；The exradius R of the circular ring metal piece of electrode under the outer ring top electrode and outer ringeWith inner circle radius reRatio
Example is 4:3；The inner circle radius r of the circular ring metal piece of electrode under the outer ring top electrode and outer ringe, with inner ring top electrode and
The exradius R of the circular ring metal piece of electrode under inner ringiRatio be 6:5.
A kind of implementation of the microcavity: being provided with through-hole through buried oxide layer center, and it is logical that this is corresponded in silicon substrate layer
Hole site is provided with blind hole, and microcavity is formed by the through-hole and blind hole, is closed cavity, and microcavity height is 1~10 micron.The double frequency
Piezoelectric type micromachined ultrasonic transducer the preparation method is as follows:
Step 1. deposits 0.5~5 micron of SiO on the silicon substrate with a thickness of 200~800 microns2, as buried oxide layer；
Step 2. etched downwards by buried oxide layer height be 1~10 micron, the cylindrical chamber that diameter is 10~10000 microns,
Wherein buried oxide layer is cut through；
The silicon that cladding thickness is 0.1~10 micron in step 3. buried oxide layer closes cylindrical chamber as silicon device layer,
Form microcavity；
Step 4. metallic film that deposition thickness is 100~300 nanometers in silicon device layer, then passes through chemical wet etching work
Lower electrode pattern is transferred on metallic film by skill, forms lower metal electrode layer；
PZT, AlN or ZnO that deposition thickness is 0.1~10 micron on step 5. lower metal electrode layer, then pass through photoetching
Piezoelectric material film pattern is successively transferred to piezoelectric material film by etching technics, forms piezoelectric thin film layer；
Step 6. metallic film that deposition thickness is 100~300 nanometers on piezoelectric thin film layer, then passes through chemical wet etching
Top electrode pattern is transferred on metallic film by technique, forms electrode of metal layer.
The microcavity another kind implementation: through oxygen is buried and silicon substrate layer center is provided with through-hole, microcavity is by this
Through-hole is formed, and is the cavity of one end open.The double frequency piezoelectric type micromachined ultrasonic transducer the preparation method is as follows:
Step 1. deposits 0.5~5 micron of SiO on the silicon substrate with a thickness of 200~800 microns2, as buried oxide layer；
The silicon that cladding thickness is 0.1~10 micron in step 2. buried oxide layer, as silicon device layer；
Step 3. metallic film that deposition thickness is 100~300 nanometers in silicon device layer, then passes through chemical wet etching work
Lower electrode pattern is transferred on metallic film by skill, forms lower metal electrode layer；
PZT, AlN or ZnO that deposition thickness is 0.1~10 micron on step 4. lower metal electrode layer, then pass through photoetching
Piezoelectric material film pattern is successively transferred to piezoelectric material film by etching technics, forms piezoelectric thin film layer；
Step 5. metallic film that deposition thickness is 100~300 nanometers on piezoelectric thin film layer, then passes through chemical wet etching
Top electrode pattern is transferred on metallic film by technique, forms electrode of metal layer；
Step 6. is upwards cut through silicon substrate and buried oxide layer in center by silicon substrate bottom surface, formed diameter be 10~
10000 microns of cylindrical microcavities, top surface, that is, silicon device layer bottom surface of microcavity.
Further, the electrode of metal layer and lower metal electrode layer be gold, titanium, chromium, aluminium, platinum, copper single layer or times
The double-layer metal film of two kinds of meaning.
From the point of view of working principle, double frequency piezoelectric type micromachined ultrasonic transducer utilizes the first two mode of resonance of vibrating diaphragm
State, and conventional piezoelectric formula micromachined ultrasonic transducer only utilizes first resonance mode.Utilize the difficult point of the first two resonance mode
It is how to avoid interfering with each other between two resonance modes.The present invention is to two pairs of annular electrodes (i.e. inner rings of electrode and outer ring
Electrode) positions and dimensions optimize, the vibration crosstalk between two kinds of resonance modes to eliminate vibrating diaphragm.Of the invention
Double frequency piezoelectric type micromachined ultrasonic transducer can be simultaneously emitted by the broadband of two kinds of different center frequencies on single vibrating diaphragm
Ultrasound, manufacturing process is simple, relative to the traditional double-frequency ultrasound energy converter being assembled by two kinds of single band ultrasonic components, has ruler
It is very little it is small, low in energy consumption, can scale of mass production, be conducive to the advantages such as Wave beam forming, be suitable for double frequency-band on piece ultrasound
(ultrasound-on-a-chip) system.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of double frequency piezoelectric type micromachined ultrasonic transducer of the invention；
Fig. 2 is the planar structure schematic diagram of piezoelectric thin film layer in Fig. 1；
Fig. 3 is the planar structure schematic diagram of electrode of metal layer in Fig. 1；
Fig. 4 is the planar structure schematic diagram of lower metal electrode layer in Fig. 1；
Fig. 5-1 is the A-A diagrammatic cross-section of electrode of metal layer, piezoelectric thin film layer, lower metal electrode layer in Fig. 1；
Fig. 5-2 is the B-B diagrammatic cross-section of electrode of metal layer, piezoelectric thin film layer, lower metal electrode layer in Fig. 1；
Fig. 6-1 is a kind of A-A diagrammatic cross-section of embodiment of Fig. 1；
Fig. 6-2 is the A-A diagrammatic cross-section of Fig. 1 another embodiment；
Fig. 7 is that electrode position and width optimize exemplary diagram；
Fig. 8 is the frequency response simulation result diagram of double frequency piezoelectric type micromachined ultrasonic transducer；
Fig. 9 is double frequency piezoelectric type micromachined ultrasonic transducer array schematic diagram.
Specific embodiment
Carry out the present invention is described in detail below in conjunction with the drawings and specific embodiments.
As shown in Figure 1, a kind of double frequency piezoelectric type micromachined ultrasonic transducer, generally cross section are the cylinders of square,
The side length of square is 20~20000 microns；It from top to bottom successively include under electrode of metal layer 1, piezoelectric thin film layer 2, metal
Electrode layer 3, silicon device layer 4, buried oxide layer 5, silicon substrate layer 6.
The center of buried oxide layer 5 and silicon substrate layer 6 is provided with microcavity, and microcavity is 10~10000 microns of cylinders of diameter, passes through
The setting of buried oxide layer 5 is worn, silicon device layer 4 is adhered in buried oxide layer 5, by the top closed of microcavity.Silicon device layer 4, buried oxide layer 5, silicon lining
Bottom 6 forms typical SOI (silicon in insulating substrate) structure.Silicon device layer 4 is with a thickness of 0.1~10 micron, 5 thickness of buried oxide layer
It is 0.5~5 micron, silicon substrate layer 6 is with a thickness of 200~800 microns.
As shown in Fig. 2, piezoelectric thin film layer 2 is arranged between electrode of metal layer 1 and lower metal electrode layer 3, including it is located at
The conplane square frame 2-1 and circular piece 2-2 being arranged in outline border, circular piece 2-2 are arranged concentrically with microcavity 7, round
The outer of piece 2-2 is connect with the middle position on tetra- side square frame 2-1, two square frame 2-1 opposite vertex respectively with circle
The outer of shape piece 2-2 is connected by strip piece；The material of piezoelectric thin film layer 2 be PZT, AlN or ZnO, it is micro- with a thickness of 0.1~10
Rice.
As shown in figure 3, electrode of metal layer 1 includes being generally aligned in the same plane non-touching two circular ring shape top electrodes, point
It Wei not outer ring top electrode 1-1 and inner ring top electrode 1-2.
Outer ring top electrode 1-1 includes the bullion piece being wholely set and the circular ring metal piece with opening, bar shaped gold
Belong to one end of piece and be connected to circular ring metal piece outer, the other end extends to the interposition on one side square frame 2-1 of piezoelectric thin film layer
It sets.
Inner ring top electrode 1-2 includes the bullion piece being wholely set and complete circular ring metal piece, bullion piece
One end is connected to circular ring metal piece outer, and the other end passes through the square frame 2-1 (figure that the opening extends to piezoelectric thin film layer
Dotted line frame in 3) vertex that crosses of both sides, and it is corresponding with a strip piece position of piezoelectric thin film layer 2.
The circular ring metal piece of outer ring top electrode 1-1 and inner ring top electrode 1-2 are arranged concentrically with microcavity 7, and outer ring powers on
The outer diameter of the circular ring metal piece of pole 1-1 is less than the internal diameter of microcavity 7.
As shown in figure 4, lower metal electrode layer 3 includes being generally aligned in the same plane electrode under non-touching two circular ring shapes, point
It Wei not electrode 3-2 under electrode 3-1 and inner ring under outer ring.
Electrode 3-1 includes the bullion piece being wholely set and the circular ring metal piece with opening, bar shaped gold under outer ring
Belong to one end of piece and be connected to circular ring metal piece outer, the other end extends to the interposition on 4 one side (dotted line frame in Fig. 4) of silicon device layer
It sets.
Electrode 3-2 includes the bullion piece being wholely set and complete circular ring metal piece, bullion piece under inner ring
One end is connected to circular ring metal piece outer, and the other end extends to the vertex that 4 both sides of silicon device layer cross, and with piezoelectric thin film layer 2
Another strip piece position it is corresponding.
The circular ring metal piece of electrode 3-2 is arranged concentrically with microcavity 7 under electrode 3-1 and inner ring under outer ring, electric under outer ring
The outer diameter of the circular ring metal piece of pole 3-1 is less than the internal diameter of microcavity 7.
Electrode of metal layer 1 and lower metal electrode layer 3 are gold, titanium, chromium, aluminium, platinum, copper with a thickness of 100~300 nanometers
Single layer or any two kinds of double-layer metal film, such as 200nm Pt/20nm Ti double-layer metal film.
The circular ring metal plate shape and size phase of the circular ring metal piece of outer ring top electrode 1-1 and electrode 3-1 under outer ring
Together, position is corresponding, aperture position central symmetry；The bullion of electrode under the bullion piece and outer ring of outer ring top electrode 1-1
Plate shape is identical with size, extends respectively to the middle position on the adjacent both sides square frame 2-1 of piezoelectric thin film layer.
As shown in Fig. 5-1 and 5-2, the circular ring shape gold of electrode 3-2 under the circular ring metal piece and inner ring of inner ring top electrode 1-2
It is identical with size to belong to plate shape, position is corresponding；The bar shaped gold of electrode 3-2 under the bullion piece and inner ring of inner ring top electrode 1-2
It is identical with size to belong to plate shape, extends respectively to two opposite vertex of the square frame 2-1 of thin film layer, thin film layer 2
Two strip pieces are corresponding with the bullion piece position of electrode 3-2 under inner ring top electrode 1-2 and inner ring respectively.
The exradius R of the circular ring metal piece of electrode 3-2 under inner ring top electrode 1-2 and inner ringiWith inner circle radius riRatio
Example is 5:2；The exradius R of the circular ring metal piece of electrode 3-1 under the outer ring top electrode 1-1 and outer ringeWith inner circle half
Diameter reRatio be 4:3；The inner circle radius r of the circular ring metal piece of electrode 3-1 under the outer ring top electrode 1-1 and outer ringe,
With the exradius R of the circular ring metal piece of electrode 3-2 under inner ring top electrode 1-2 and inner ringiRatio be 6:5.
As in Figure 6-1, a kind of implementation of microcavity: through-hole is provided with through 5 center of buried oxide layer, in silicon substrate layer 6
The corresponding lead to the hole site is provided with blind hole, and microcavity 7 is formed by the through-hole and blind hole, is closed cavity, is highly 1~10 micron.
The double frequency piezoelectric type micromachined ultrasonic transducer the preparation method is as follows:
Step 1. deposits 0.5~5 micron of SiO on the silicon substrate 6 with a thickness of 200~800 microns2, as buried oxide layer
5；
By buried oxide layer 5, etching height is 1~10 micron, the cylindrical cavity that diameter is 10~10000 microns to step 2. downwards
Body, wherein buried oxide layer 5 is cut through；
The silicon that cladding thickness is 0.1~10 micron in step 3. buried oxide layer 5, as silicon device layer (4), by circular cylindrical cavity
Closing forms microcavity 7；
Step 4. metallic film that deposition thickness is 100~300 nanometers in silicon device layer 4, then passes through chemical wet etching
Lower electrode pattern is transferred on metallic film by technique, forms lower metal electrode layer 3；
PZT, AlN or ZnO that deposition thickness is 0.1~10 micron on step 5. lower metal electrode layer 3, then pass through photoetching
Piezoelectric material film pattern is successively transferred to piezoelectric material film by etching technics, forms piezoelectric thin film layer 2；
Step 6. metallic film that deposition thickness is 100~300 nanometers on piezoelectric thin film layer 2, is then carved by photoetching
Top electrode pattern is transferred on metallic film by etching technique, forms electrode of metal layer 1.
As in fig. 6-2, it microcavity another kind implementation: is provided with through buried oxide layer 5 and 6 center of silicon substrate layer logical
Hole, microcavity 7 are formed by the through-hole, are the cavity of one end open.When microcavity 7 penetrates silicon substrate layer 6, it is meant that can directly lead to
Too deep silicon etching process processes, and manufacturing process is simpler, and cost is lower, unlike the microcavity for being embedded in centre, penetrates
Air is filled in the microcavity 7 of silicon substrate layer.The double frequency piezoelectric type micromachined ultrasonic transducer the preparation method is as follows:
Step 1. deposits 0.5~5 micron of SiO on the silicon substrate with a thickness of 200~800 microns2, as buried oxide layer 5；
The silicon that cladding thickness is 0.1~10 micron in step 2. buried oxide layer 5, as silicon device layer 4；
Step 3. metallic film that deposition thickness is 100~300 nanometers in silicon device layer 4, then passes through chemical wet etching
Lower electrode pattern is transferred on metallic film by technique, forms lower metal electrode layer 3；
PZT, AlN or ZnO that deposition thickness is 0.1~10 micron on step 4. lower metal electrode layer 3, then pass through photoetching
Piezoelectric material film pattern is successively transferred to piezoelectric material film by etching technics, forms piezoelectric thin film layer 2；
Step 5. metallic film that deposition thickness is 100~300 nanometers on piezoelectric thin film layer 2, is then carved by photoetching
Top electrode pattern is transferred on metallic film by etching technique, forms electrode of metal layer 1；
Step 6. is upwards cut through silicon substrate 6 and buried oxide layer 5 in center by silicon substrate bottom surface, formed diameter be 10~
10000 microns of cylindrical microcavity 7, the bottom surface of top surface, that is, silicon device layer 4 of microcavity 7.
As shown in fig. 7, first optimizing to the positions and dimensions of top electrode under single pair electrode case, all possibility are scanned
Parameter combination.The left side Fig. 7 indicates the average displacement that generates on vibrating diaphragm under the excitation of 12V voltage, it can be seen that each
It is all peak value at 3.75MHz and 18MHz two under the conditions of kind, as the first two natural reonant frequency；Fig. 7 right-hand component indicates
The distribution of average displacement value at 3.75MHz and 18MHz two and the average displacement ratio of 3.75/18MHz or 18/3.75MHz
The ratio between (i.e. the ratio between the average displacement at average displacement and 18MHz at 3.75MHz, or in turn).3.75/18MHz average
Displacement Ratio height indicates that the first resonance is significant under this condition and the second resonance is not significant, mainly shows the first resonance mode, second
Resonance mode there's almost no；18/3.75MHz average displacement indicates that first is total under this condition, the second resonance mode is significant than high
Mode of shaking is unobvious.Since both of which mainly shows a different resonance mode, both of these case is folded
After adding, mutual interference can very little.In this example, optimum results are inner rings of electrode parameters are as follows: Ri=5, ri=2；
Outer ring electrode parameter are as follows: Re=8, re=6.
Shown in Fig. 8, two width-pulses that amplitude is 12V and 24V are separately input to inner rings of electrode and outer ring electrode (figure
After 8a), the simulation result of Fig. 8 b and Fig. 8 c are obtained, Fig. 8 b indicates dynamic respond at vibrating diaphragm center；Fig. 8 c indicates edge
Pressure response at 0.62 millimeter from vibrating diaphragm center of acoustic axis.It can be seen that two pairs of electrodes motivate generated result simultaneously
Motivate the sum of generated result almost equal respectively with two single pair electrodes.This explanation, after electrode parameter optimizes, two pairs
Electrode motivates be not found significant crosstalk simultaneously, can be simultaneously emitted by or receive the sound of two kinds of frequency bands.
The representative configuration of double frequency piezoelectric type micromachined ultrasonic transducer array is as shown in figure 9, in the inner ring of same row or column
Electrode is connected to liner 11, and correspondingly, the outer ring top electrode of same row or column is connected to liner 12, liner 11 and liner 12
It is typically distributed on the opposite two sides in ultrasound transducer array edge.Top electrode layout, which is rotated by 90 °, can be obtained lower electrode lay-out.
Similarly, electrode is connected to liner 21 under the inner ring of same column or row, and electrode is connected to liner under the outer ring of same column or row
22.Liner 11 and liner 21 are selectively connected, so that inner rings of electrode is powered, single ultrasonic transducer can not only be swashed
It encourages, multiple ultrasonic transducers in specific region can also be motivated.Liner 12 and liner 22 are selectively connected, is made
Outer ring electrode is powered, and can also motivate to single or more ultrasonic transducer.The control of inner rings of electrode and outer ring electrode is
Relatively independent, the incentive action of inner rings of electrode and outer ring electrode is also relatively independent.Double frequency piezoelectric type micromachined ultrasonic changes
The array size of energy device can be with infinite expanding.
So far, attached drawing is had been combined to the present invention have been described in detail.According to above description, those skilled in the art are answered
When having clear understanding to double frequency piezoelectric type micromachined ultrasonic transducer of the present invention.Particular embodiments described above,
The purpose of the present invention, technical scheme and beneficial effects are had been further described, it should be understood that the above is only
It for specific embodiments of the present invention, is not intended to restrict the invention, all within the spirits and principles of the present invention, is done
Any modification, equivalent substitution, improvement and etc. should all be included in the protection scope of the present invention.
Claims (10)
1. a kind of double frequency piezoelectric type micromachined ultrasonic transducer, generally cylinder, the diameter of regular polygon bottom surface is 20~20000
Micron；It from top to bottom successively include electrode of metal layer (1), piezoelectric thin film layer (2), lower metal electrode layer (3), silicon device layer
(4), buried oxide layer (5), silicon substrate layer (6), it is characterised in that:
The center of buried oxide layer (5) and silicon substrate layer (6) is provided with microcavity (7)；The microcavity (7) is cylinder or prismatic,
It is arranged through buried oxide layer (5), silicon device layer (4) is adhered on buried oxide layer (5), by the top closed of microcavity (7)；The silicon device
Layer (4) is with a thickness of 0.1~10 micron, and for buried oxide layer (5) with a thickness of 0.5~5 micron, silicon substrate layer (6) is micro- with a thickness of 200~800
Rice；The diameter of the microcavity (7) is 10~10000 microns；
The piezoelectric thin film layer (2) is arranged between electrode of metal layer (1) and lower metal electrode layer (3), including is located at same
The regular polygon outline border (2-1) of one plane and the circular piece (2-2) being arranged in outline border, circular piece (2-2) and microcavity (7) are concentric
Setting, the outer of circular piece (2-2) connect with the middle position on each side outline border (2-1), two vertex of outline border (2-1) respectively with
The outer of circular piece (2-2) is connected by strip piece；
The electrode of metal layer (1) includes being generally aligned in the same plane non-touching two circular ring shape top electrodes, respectively outer
Ring top electrode (1-1) and inner ring top electrode (1-2)；
Outer ring top electrode (1-1) includes the bullion piece being wholely set and the circular ring metal piece with opening, bullion
One end of piece is connected to circular ring metal piece outer, and the other end extends to the middle position on one side outline border (2-1) of piezoelectric thin film layer；
Inner ring top electrode (1-2) includes the bullion piece being wholely set and complete circular ring metal piece, bullion piece one
It is connected to circular ring metal piece outer, the other end passes through one that the opening extends to the outline border (2-1) of piezoelectric thin film layer
Vertex, and it is corresponding with a strip piece position of piezoelectric thin film layer (2)；
The circular ring metal piece of outer ring top electrode (1-1) and inner ring top electrode (1-2) is arranged concentrically with microcavity (7), on outer ring
The outer diameter of the circular ring metal piece of electrode (1-1) is less than the internal diameter of microcavity (7)；
The lower metal electrode layer (3) includes being generally aligned in the same plane electrode under non-touching two circular ring shapes, respectively outer
Electrode (3-2) under electrode (3-1) and inner ring under ring；
Electrode (3-1) includes the bullion piece being wholely set and the circular ring metal piece with opening, bullion under outer ring
One end of piece is connected to circular ring metal piece outer, and the other end extends to the middle position of another side outline border (2-1) of silicon device layer；
Electrode (3-2) includes the bullion piece being wholely set and complete circular ring metal piece, bullion piece one under inner ring
Be connected to circular ring metal piece outer, the other end pass through the opening extend to piezoelectric thin film layer outline border (2-1) it is another
A vertex, and it is corresponding with another strip piece position of piezoelectric thin film layer (2)；
The circular ring metal piece of electrode (3-2) is arranged concentrically with microcavity (7) under electrode (3-1) and inner ring under outer ring, under outer ring
The outer diameter of the circular ring metal piece of electrode (3-1) is less than the internal diameter of microcavity (7)；
The outer ring top electrode (1-1) and the circular ring metal plate shape of electrode under outer ring (3-1) identical, the position pair with size
It answers；The outer ring top electrode (1-1) is identical with size with the bullion plate shape of electrode under outer ring, extends respectively to piezoelectricity
The middle position on the different both sides of the outline border (2-1) of film layer；
The inner ring top electrode (1-2) and the circular ring metal plate shape of electrode under inner ring (3-2) identical, the position pair with size
It answers；Inner ring top electrode (1-2) is identical with size with the bullion plate shape of electrode under inner ring (3-2), and it is thin to extend respectively to electricity
Two different vertex of the outline border (2-1) of film layer, two strip pieces of thin film layer (2) respectively with inner ring top electrode (1-2) and
The bullion piece position of electrode (3-2) is corresponding under inner ring；
The exradius R of the circular ring metal piece of electrode (3-2) under the inner ring top electrode (1-2) and inner ringiWith inner circle radius
riRatio be 5:2；The exradius R of the circular ring metal piece of electrode (3-1) under the outer ring top electrode (1-1) and outer ringe
With inner circle radius reRatio be 4:3；The circular ring metal piece of electrode (3-1) under the outer ring top electrode (1-1) and outer ring
Inner circle radius re, exradius R with the circular ring metal piece of electrode (3-2) under inner ring top electrode (1-2) and inner ringiRatio
Example is 6:5.
2. a kind of double frequency piezoelectric type micromachined ultrasonic transducer as described in claim 1, it is characterised in that: run through buried oxide layer
(5) center is provided with through-hole, and the lead to the hole site is corresponded in silicon substrate layer (6) and is provided with blind hole, microcavity (7) is by the through-hole and blind hole
It is formed, is closed cavity, microcavity (7) is highly 1~10 micron.
3. a kind of double frequency piezoelectric type micromachined ultrasonic transducer as described in claim 1, it is characterised in that: run through buried oxide layer
(5) and silicon substrate layer (6) center is provided with through-hole, and microcavity (7) is formed by the through-hole, is the cavity of one end open.
4. a kind of double frequency piezoelectric type micromachined ultrasonic transducer as claimed in claim 1,2 or 3, it is characterised in that: described
The material of piezoelectric thin film layer (2) is PZT, AlN or ZnO, with a thickness of 0.1~10 micron.
5. a kind of double frequency piezoelectric type micromachined ultrasonic transducer as claimed in claim 1,2 or 3, it is characterised in that: described
Electrode of metal layer (1) is the single layer or any two kinds of bilayer gold of gold, titanium, chromium, aluminium, platinum, copper with a thickness of 100~300 nanometers
Belong to film.
6. a kind of double frequency piezoelectric type micromachined ultrasonic transducer as claimed in claim 1,2 or 3, it is characterised in that: described
Lower metal electrode layer (3) is the single layer or any two kinds of bilayer gold of gold, titanium, chromium, aluminium, platinum, copper with a thickness of 100~300 nanometers
Belong to film.
7. the method for preparing double frequency piezoelectric type micromachined ultrasonic transducer as claimed in claim 2, which is characterized in that this method
Include the following steps:
Step 1. deposits 0.5~5 micron of SiO on the silicon substrate with a thickness of 200~800 microns2, as buried oxide layer (5)；
By buried oxide layer (5), etching is highly 1~10 micron, the cylindrical chamber that diameter is 10~10000 microns to step 2. downwards,
Middle buried oxide layer (5) cuts through；
The silicon that cladding thickness is 0.1~10 micron in step 3. buried oxide layer (5) seals cylindrical chamber as silicon device layer (4)
It closes, is formed microcavity (7)；
Step 4. metallic film that deposition thickness is 100~300 nanometers on silicon device layer (4), then passes through chemical wet etching work
Lower electrode pattern is transferred on metallic film by skill, is formed lower metal electrode layer (3)；
PZT, AlN or ZnO that deposition thickness is 0.1~10 micron on step 5. lower metal electrode layer (3) are then carved by photoetching
Piezoelectric material film pattern is successively transferred to piezoelectric material film by etching technique, is formed piezoelectric thin film layer (2)；
Step 6. metallic film that deposition thickness is 100~300 nanometers on piezoelectric thin film layer (2), then passes through chemical wet etching
Top electrode pattern is transferred on metallic film by technique, is formed electrode of metal layer (1).
8. the preparation method of double frequency piezoelectric type micromachined ultrasonic transducer as claimed in claim 7, it is characterised in that:
The piezoelectric material film pattern of the piezoelectric thin film layer (2) are as follows: including the regular polygon outline border (2- being generally aligned in the same plane
1) it is arranged concentrically with the circular piece (2-2) that is arranged in outline border, circular piece (2-2) with microcavity (7), the outer of circular piece (2-2)
It is connect with the middle position on each side outline border (2-1), outer of two vertex of outline border (2-1) respectively with circular piece (2-2) passes through
Strip piece connection；
The top electrode pattern of the electrode of metal layer (1) are as follows: including being generally aligned in the same plane non-touching two circular ring shapes
Top electrode, respectively outer ring top electrode (1-1) and inner ring top electrode (1-2)；
Outer ring top electrode (1-1) includes the bullion piece being wholely set and the circular ring metal piece with opening, bullion
One end of piece is connected to circular ring metal piece outer, and the other end extends to the middle position on one side outline border (2-1) of piezoelectric thin film layer；
Inner ring top electrode (1-2) includes the bullion piece being wholely set and complete circular ring metal piece, bullion piece one
It is connected to circular ring metal piece outer, the other end passes through one that the opening extends to the outline border (2-1) of piezoelectric thin film layer
Vertex, and it is corresponding with a strip piece position of piezoelectric thin film layer (2)；
The circular ring metal piece of outer ring top electrode (1-1) and inner ring top electrode (1-2) is arranged concentrically with microcavity (7), on outer ring
The outer diameter of the circular ring metal piece of electrode (1-1) is less than the internal diameter of microcavity (7)；
The lower electrode pattern of the lower metal electrode layer (3) are as follows: including being generally aligned in the same plane non-touching two circular ring shapes
Lower electrode, electrode (3-2) under electrode (3-1) and inner ring respectively under outer ring；
Electrode (3-1) includes the bullion piece being wholely set and the circular ring metal piece with opening, bullion under outer ring
One end of piece is connected to circular ring metal piece outer, and the other end extends to the middle position of another side outline border (2-1) of silicon device layer；
Electrode (3-2) includes the bullion piece being wholely set and complete circular ring metal piece, bullion piece one under inner ring
Be connected to circular ring metal piece outer, the other end pass through the opening extend to piezoelectric thin film layer outline border (2-1) it is another
A vertex, and it is corresponding with another strip piece position of piezoelectric thin film layer (2)；
The circular ring metal piece of electrode (3-2) is arranged concentrically with microcavity (7) under electrode (3-1) and inner ring under outer ring, under outer ring
The outer diameter of the circular ring metal piece of electrode (3-1) is less than the internal diameter of microcavity (7)；
The outer ring top electrode (1-1) and the circular ring metal plate shape of electrode under outer ring (3-1) identical, the position pair with size
It answers；The outer ring top electrode (1-1) is identical with size with the bullion plate shape of electrode under outer ring, extends respectively to piezoelectricity
The middle position on the different both sides of the outline border (2-1) of film layer；
The inner ring top electrode (1-2) and the circular ring metal plate shape of electrode under inner ring (3-2) identical, the position pair with size
It answers；Inner ring top electrode (1-2) is identical with size with the bullion plate shape of electrode under inner ring (3-2), and it is thin to extend respectively to electricity
Two different vertex of the outline border (2-1) of film layer, two strip pieces of thin film layer (2) respectively with inner ring top electrode (1-2) and
The bullion piece position of electrode (3-2) is corresponding under inner ring；
The exradius R of the circular ring metal piece of electrode (3-2) under the inner ring top electrode (1-2) and inner ringiWith inner circle radius
riRatio be 5:2；The exradius R of the circular ring metal piece of electrode (3-1) under the outer ring top electrode (1-1) and outer ringe
With inner circle radius reRatio be 4:3；The circular ring metal piece of electrode (3-1) under the outer ring top electrode (1-1) and outer ring
Inner circle radius re, exradius R with the circular ring metal piece of electrode (3-2) under inner ring top electrode (1-2) and inner ringiRatio
Example is 6:5.
9. the method for preparing double frequency piezoelectric type micromachined ultrasonic transducer as claimed in claim 3, which is characterized in that this method
Include the following steps:
Step 1. deposits 0.5~5 micron of SiO on the silicon substrate with a thickness of 200~800 microns2, as buried oxide layer (5)；
The silicon that cladding thickness is 0.1~10 micron in step 2. buried oxide layer (5), as silicon device layer (4)；
Step 3. metallic film that deposition thickness is 100~300 nanometers on silicon device layer (4), then passes through chemical wet etching work
Lower electrode pattern is transferred on metallic film by skill, is formed lower metal electrode layer (3)；
PZT, AlN or ZnO that deposition thickness is 0.1~10 micron on step 4. lower metal electrode layer (3) are then carved by photoetching
Piezoelectric material film pattern is successively transferred to piezoelectric material film by etching technique, is formed piezoelectric thin film layer (2)；
Step 5. metallic film that deposition thickness is 100~300 nanometers on piezoelectric thin film layer (2), then passes through chemical wet etching
Top electrode pattern is transferred on metallic film by technique, is formed electrode of metal layer (1)；
Step 6. is upwards cut through silicon substrate (6) and buried oxide layer (5) in center by silicon substrate bottom surface, formed diameter be 10~
10000 microns of cylindrical microcavities (7), the bottom surface of top surface, that is, silicon device layer (4) of microcavity (7).
10. the preparation method of double frequency piezoelectric type micromachined ultrasonic transducer as claimed in claim 9, it is characterised in that:
The piezoelectric material film pattern of the piezoelectric thin film layer (2) are as follows: including the regular polygon outline border (2- being generally aligned in the same plane
1) it is arranged concentrically with the circular piece (2-2) that is arranged in outline border, circular piece (2-2) with microcavity (7), the outer of circular piece (2-2)
It is connect with the middle position on each side outline border (2-1), outer of two vertex of outline border (2-1) respectively with circular piece (2-2) passes through
Strip piece connection；
The top electrode pattern of the electrode of metal layer (1) are as follows: including being generally aligned in the same plane non-touching two circular ring shapes
Top electrode, respectively outer ring top electrode (1-1) and inner ring top electrode (1-2)；
Outer ring top electrode (1-1) includes the bullion piece being wholely set and the circular ring metal piece with opening, bullion
One end of piece is connected to circular ring metal piece outer, and the other end extends to the middle position on one side outline border (2-1) of piezoelectric thin film layer；
Inner ring top electrode (1-2) includes the bullion piece being wholely set and complete circular ring metal piece, bullion piece one
It is connected to circular ring metal piece outer, the other end passes through one that the opening extends to the outline border (2-1) of piezoelectric thin film layer
Vertex, and it is corresponding with a strip piece position of piezoelectric thin film layer (2)；
The circular ring metal piece of outer ring top electrode (1-1) and inner ring top electrode (1-2) is arranged concentrically with microcavity (7), on outer ring
The outer diameter of the circular ring metal piece of electrode (1-1) is less than the internal diameter of microcavity (7)；
The lower electrode pattern of the lower metal electrode layer (3) are as follows: including being generally aligned in the same plane non-touching two circular ring shapes
Lower electrode, electrode (3-2) under electrode (3-1) and inner ring respectively under outer ring；
Electrode (3-1) includes the bullion piece being wholely set and the circular ring metal piece with opening, bullion under outer ring
One end of piece is connected to circular ring metal piece outer, and the other end extends to the middle position of another side outline border (2-1) of silicon device layer；
Electrode (3-2) includes the bullion piece being wholely set and complete circular ring metal piece, bullion piece one under inner ring
Be connected to circular ring metal piece outer, the other end pass through the opening extend to piezoelectric thin film layer outline border (2-1) it is another
A vertex, and it is corresponding with another strip piece position of piezoelectric thin film layer (2)；
The circular ring metal piece of electrode (3-2) is arranged concentrically with microcavity (7) under electrode (3-1) and inner ring under outer ring, under outer ring
The outer diameter of the circular ring metal piece of electrode (3-1) is less than the internal diameter of microcavity (7)；
The outer ring top electrode (1-1) and the circular ring metal plate shape of electrode under outer ring (3-1) identical, the position pair with size
It answers；The outer ring top electrode (1-1) is identical with size with the bullion plate shape of electrode under outer ring, extends respectively to piezoelectricity
The middle position on the different both sides of the outline border (2-1) of film layer；
The inner ring top electrode (1-2) and the circular ring metal plate shape of electrode under inner ring (3-2) identical, the position pair with size
It answers；Inner ring top electrode (1-2) is identical with size with the bullion plate shape of electrode under inner ring (3-2), and it is thin to extend respectively to electricity
Two different vertex of the outline border (2-1) of film layer, two strip pieces of thin film layer (2) respectively with inner ring top electrode (1-2) and
The bullion piece position of electrode (3-2) is corresponding under inner ring；
The exradius R of the circular ring metal piece of electrode (3-2) under the inner ring top electrode (1-2) and inner ringiWith inner circle radius
riRatio be 5:2；The exradius R of the circular ring metal piece of electrode (3-1) under the outer ring top electrode (1-1) and outer ringe
With inner circle radius reRatio be 4:3；The circular ring metal piece of electrode (3-1) under the outer ring top electrode (1-1) and outer ring
Inner circle radius re, exradius R with the circular ring metal piece of electrode (3-2) under inner ring top electrode (1-2) and inner ringiRatio
Example is 6:5.
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