CN203071889U - Piezoelectric resonator - Google Patents
Piezoelectric resonator Download PDFInfo
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- CN203071889U CN203071889U CN 201320011344 CN201320011344U CN203071889U CN 203071889 U CN203071889 U CN 203071889U CN 201320011344 CN201320011344 CN 201320011344 CN 201320011344 U CN201320011344 U CN 201320011344U CN 203071889 U CN203071889 U CN 203071889U
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Abstract
The utility model discloses a piezoelectric resonator comprising a work zone, wherein the work zone consists of a piezoelectric film layer, an upper metal electrode and a lower metal electrode; the upper metal electrode is formed on an upper surface of the piezoelectric film layer, the lower metal electrode is formed on a lower surface of the piezoelectric film layer, and the piezoelectric film layer consists of a central column piezoelectrics and a plurality of different diameter of cylindrical piezoelectrics. The small-diameter cylindrical piezoelectrics is coaxially arranged inside of the large-diameter cylindrical piezoelectrics. The central column piezoelectrics is coaxially mounted inside of the cylindrical piezoelectrics having the smallest diameter. The advantages are that the structure reduces amplitude of a parasitic vibration mode and can effectively raise electromechanical coupling factor.
Description
Technical field
The utility model relates to a kind of resonator, especially relates to a kind of piezo-electric resonator.
Background technology
In electronic equipments such as modern communication, navigator, computer, household electrical appliance and medical treatment detection, comprised a large amount of electrical resonator equifrequent devices.Yet, along with the fast development of science and technology, increasing functional requirement having been proposed electronic equipment, this is just also more and more higher, more and more to the requirement of frequency device, such as microminiaturization, high-frequency, high-performance, low-power consumption and low cost etc.The technology that frequency device adopts usually has microwave-medium ceramics technology, surface acoustic wave techniques and bulk acoustic wave technology.Though the microwave-medium ceramics resonator has good performance, volume is bigger; SAW (Surface Acoustic Wave) resonator (SAW) is though volume is less, exist operating frequency not high, insert that loss is big, power capacity is lower, performance varies with temperature shortcomings such as drift is obvious; Bulk acoustic wave resonator (BAW) combines the advantage of microwave-medium ceramics resonator and SAW (Surface Acoustic Wave) resonator, overcomes simultaneously both shortcomings again, and (600MHz～20GHz), temperature coefficient is little, capacity is big, volume is little, cost is low for its operating frequency height.
Piezoelectric film bulk acoustic wave resonator (Film bulk acoustic resonator is called for short FBAR) is a kind of bulk acoustic wave resonator that occurs in recent ten years.Its basic structure is to add metal electrode up and down and the laminate sandwich structure that constitutes by one deck piezoelectric film material.When an alternating voltage signal acts on this metal-film-metal sandwich structure, mediate the piezoelectric film material of layer because inverse piezoelectric effect, can produce mechanical deformation, can make piezoelectric thin film layer produce expansion along with the variation of electric field, shrink, thereby form vibration.On know-why, FBAR adopts the bulk acoustic wave technology, the more important thing is, FBAR can be produced on the matrixes such as pottery, silicon chip, its manufacture craft can with the semiconductor technology compatibility, be can and radio frequency integrated circuit (RFIC) or the integrated resonator of monolithic integrated microwave circuit (MMIC), meet the direction of modern electronic devices development.
Common piezoelectric film bulk acoustic wave resonator has three types of film-type, air-gap type and solid-state assembly types.The piezoelectric film bulk acoustic wave resonator of film-type and air-gap type mainly comprises upper electrode, piezoelectric membrane body, lower electrode, supporting layer and substrate layer, such piezoelectric film bulk acoustic wave resonator mainly utilizes the approximate zero impedance of air to limit sound wave or energy spills from the piezoelectric membrane body, elastic wave is limited in the resonator vibrates; The piezoelectric film bulk acoustic wave resonator of solid-state assembly type mainly comprises upper electrode, piezoelectric membrane body, lower electrode, acoustic reflecting layer and substrate layer, acoustic reflecting layer alternately is made of mutually low resistivity materials and the highly-resistant material of 1/4th wave length of sound thickness, and acoustic reflecting layer is used for stoping sound wave or energy to import substrate layer into.
Above-mentioned various types of piezoelectric film bulk acoustic wave resonator can produce principal oscillation pattern (comprising thickness stretching vibration pattern and thickness shear vibration mode) in the course of the work, also can produce parasitic vibration mode.Parasitic vibration mode is caused that by piezoelectric membrane body side surface border its stability to the frequency of piezoelectric film bulk acoustic wave resonator can have a negative impact, and therefore is necessary to eliminate and weaken by the structure of improving resonator the vibration of spurious mode.
Summary of the invention
Technical problem to be solved in the utility model provides and a kind ofly can weaken or eliminate parasitic vibration mode effectively, and can improve the piezo-electric resonator of electromechanical coupling factor and quality factor effectively.
The utility model solves the problems of the technologies described above the technical scheme that adopts: a kind of piezo-electric resonator, comprise the service area, described service area is by piezoelectric thin film layer and be formed at the last metal electrode on the upper surface of described piezoelectric thin film layer and the following metal electrode that is formed on the lower surface of described piezoelectric thin film layer is formed, it is characterized in that described piezoelectric thin film layer is made up of the tubular piezoelectrics that centered cylinder piezoelectrics and a plurality of diameter of equal altitudes has nothing in common with each other, coaxial large diameter described tubular piezoelectrics, the coaxial described tubular piezoelectrics with minimum diameter that are positioned at of described centered cylinder piezoelectrics of being positioned at of the described tubular piezoelectrics of minor diameter.
Described centered cylinder piezoelectrics are solid cylindric piezoelectrics or are hollow cylindric piezoelectrics.
The wall thickness of described tubular piezoelectrics is (0.5～1.5) with the ratio of the height of described tubular piezoelectrics: 1.
The height of described centered cylinder piezoelectrics and described tubular piezoelectrics is 0.5～4 μ m.
The width of the annular gap between adjacent two described tubular piezoelectrics is 0.2～0.5 μ m, and having the described tubular piezoelectrics of minimum diameter and the width of the annular gap between the described centered cylinder piezoelectrics is 0.2～0.5 μ m.
Described annular gap is filled by air or non-piezoelectric material.
External diameter with described tubular piezoelectrics of maximum gauge is 50 μ m～200 μ m.
This piezo-electric resonator also comprise substrate layer and be arranged at described substrate layer and described service area between supporting layer, described substrate layer offers the air gap along the lower surface that short transverse extends to described supporting layer, described air gap makes the lower surface of described supporting layer directly contact with air, and acoustic wave energy is limited in the described service area.
This piezo-electric resonator also comprise substrate layer and be arranged at described substrate layer and described service area between supporting layer, the top of described substrate layer offers air-gap, described air-gap makes the lower surface of described supporting layer directly contact with air, and acoustic wave energy is limited in the described service area.
This piezo-electric resonator also comprise substrate layer and be arranged at described substrate layer and described service area between and be used for acoustic wave energy is limited in Prague acoustic reflection layer in the described service area, described Prague acoustic reflection layer is that the high impedance layer of 1/4th wave length of sounds and low impedance layers that a plurality of thickness is 1/4th wave length of sounds are superimposed and form by a plurality of thickness.
Compared with prior art, advantage of the present utility model is: utilize centered cylinder piezoelectrics of equal altitudes and tubular piezoelectrics that a plurality of diameter has nothing in common with each other to form piezoelectric thin film layer, and be arranged in the large diameter tubular piezoelectrics the tubular piezoelectrics of minor diameter are coaxial, be arranged in the tubular piezoelectrics with minimum diameter the centered cylinder piezoelectrics are coaxial, make and have the annular gap between the tubular piezoelectrics of the tubular piezoelectrics of centered cylinder piezoelectrics and minimum diameter and different-diameter, this structure has not only reduced the amplitude of parasitic vibration mode, and can improve electromechanical coupling factor (can reach 0.115) effectively, compare existing piezoelectric film bulk acoustic wave resonator, can improve approximately 30～40%, can improve quality factor effectively simultaneously.
Description of drawings
Fig. 1 is the structural representation of the piezo-electric resonator of embodiment one;
Fig. 2 is the structural representation of the piezo-electric resonator of embodiment two;
Fig. 3 is the structural representation of the piezo-electric resonator of embodiment three;
Fig. 4 is the schematic top plan view of piezoelectric thin film layer.
Embodiment
Describe in further detail below in conjunction with the utility model of accompanying drawing embodiment.
Embodiment one:
A kind of piezo-electric resonator that present embodiment proposes, as shown in Figure 1 and Figure 4, it is the film-type piezo-electric resonator, it comprises service area 1, the substrate layer 2 that is fabricated from a silicon and be arranged at substrate layer 2 and service area 1 between supporting layer 3, service area 1 is by piezoelectric thin film layer 11 and be formed at the last metal electrode 12 on the upper surface of piezoelectric thin film layer 11 and the following metal electrode 13 that is formed on the lower surface of piezoelectric thin film layer 11 is formed, piezoelectric thin film layer 11 is made up of the tubular piezoelectrics 112 that centered cylinder piezoelectrics 111 and a plurality of diameter of equal altitudes has nothing in common with each other, the tubular piezoelectrics of minor diameter are coaxial to be positioned at large diameter tubular piezoelectrics, the centered cylinder piezoelectrics 111 coaxial tubular piezoelectrics with minimum diameter that are positioned at, substrate layer 2 offers air gap 21 along the lower surface that short transverse extends to supporting layer 3, namely form air gap 21 at the substrate layer 2 that is fabricated from a silicon by silicon body reverse side etching, this air gap 21 makes the lower surface of supporting layer 3 directly contact with air, and acoustic wave energy is limited in the service area 1.
In the present embodiment, the wall thickness that generally requires tubular piezoelectrics 112 is (0.5～1.5) with the ratio of the height of tubular piezoelectrics 112: 1, verify by finite element numerical simultaneously, the more thin combination property that more can improve piezo-electric resonator of wall that shows tubular piezoelectrics 112, but because if the wall of tubular piezoelectrics 112 is too thin, therefore then manufacture difficulty is big, can consider according to actual conditions are compromise, is made as 0.7:1 as the ratio with the wall thickness of tubular piezoelectrics 112 and the height of tubular piezoelectrics 112; On the other hand, if in the actual fabrication process, in order to reduce cost of manufacture, then can suitably sacrifice the performance of piezo-electric resonator, can increase the thickness of the wall of tubular piezoelectrics 112, as the ratio of the wall thickness of tubular piezoelectrics 112 and the height of tubular piezoelectrics 112 being made as 1.2:1.
In the present embodiment, the height of the piezoelectric membrane body in the height of centered cylinder piezoelectrics 111 and tubular piezoelectrics 112 and the existing film-type piezoelectric film bulk acoustic wave resonator is similar, generally the height of centered cylinder piezoelectrics 111 and tubular piezoelectrics 112 all can be made as 0.5～4 μ m, in the actual course of processing, the height of centered cylinder piezoelectrics 111 and tubular piezoelectrics 112 all can be made as 2 μ m, if the wall thickness of tubular piezoelectrics 112 is 0.7:1 with the ratio of the height of tubular piezoelectrics 112, then the wall thickness of tubular piezoelectrics 112 is 1.4 μ m.
In the present embodiment, the width W of the annular gap between adjacent two tubular piezoelectrics 112, the tubular piezoelectrics with minimum diameter and the annular gap between the centered cylinder piezoelectrics 111 all can be made as 0.2～0.5 μ m, in the actual course of processing, the width W of the annular gap between adjacent two tubular piezoelectrics 112, the tubular piezoelectrics with minimum diameter and the annular gap between the centered cylinder piezoelectrics 111 all can be made as 0.3 μ m, can be filled by air or existing non-piezoelectric material in this each annular gap.
In the present embodiment, external diameter with tubular piezoelectrics of maximum gauge can be made as 50 μ m～200 μ m, in specific operation process, can determine to have the occurrence of external diameter of the tubular piezoelectrics of maximum gauge as the case may be, as the external diameter with tubular piezoelectrics of maximum gauge being made as 100 μ m.
Embodiment two:
A kind of piezo-electric resonator that present embodiment proposes, as Fig. 2 and shown in Figure 4, it is air-gap type piezo-electric resonator, it comprises service area 1, the substrate layer 2 that is fabricated from a silicon and be arranged at substrate layer 2 and service area 1 between supporting layer 3, service area 1 is by piezoelectric thin film layer 11 and be formed at the last metal electrode 12 on the upper surface of piezoelectric thin film layer 11 and the following metal electrode 13 that is formed on the lower surface of piezoelectric thin film layer 11 is formed, piezoelectric thin film layer 11 is made up of the tubular piezoelectrics 112 that centered cylinder piezoelectrics 111 and a plurality of diameter of equal altitudes has nothing in common with each other, the tubular piezoelectrics of minor diameter are coaxial to be positioned at large diameter tubular piezoelectrics, the centered cylinder piezoelectrics 111 coaxial tubular piezoelectrics with minimum diameter that are positioned at, the top of substrate layer 2 offers air-gap 22, can form air-gap 22 by removing the part silicon chip at the upper surface of the substrate layer 2 that is fabricated from a silicon, this air-gap 22 makes the lower surface of supporting layer 3 directly contact with air, and acoustic wave energy is limited in the service area 1.
In the present embodiment, width of the width of the annular gap between the height of the ratio of the height of the wall thickness of tubular piezoelectrics 112 and tubular piezoelectrics 112, centered cylinder piezoelectrics 111 and tubular piezoelectrics 112, adjacent two the tubular piezoelectrics 112, the tubular piezoelectrics with minimum diameter and the annular gap between the centered cylinder piezoelectrics 111 etc. can be determined occurrence according to the scope that embodiment one provides in conjunction with concrete condition.
Embodiment three:
A kind of piezo-electric resonator that present embodiment proposes, as shown in Figure 3 and Figure 4, it is solid-state assembly type piezo-electric resonator, it comprises service area 1, the substrate layer 2 that is fabricated from a silicon and be arranged at substrate layer 2 and service area 1 between and be used for acoustic wave energy is limited in Prague acoustic reflection layer 4 in the service area, service area 1 is by piezoelectric thin film layer 11 and be formed at the last metal electrode 12 on the upper surface of piezoelectric thin film layer 11 and the following metal electrode 13 that is formed on the lower surface of piezoelectric thin film layer 11 is formed, piezoelectric thin film layer 11 is made up of the tubular piezoelectrics 112 that centered cylinder piezoelectrics 111 and a plurality of diameter of equal altitudes has nothing in common with each other, the tubular piezoelectrics of minor diameter are coaxial to be positioned at large diameter tubular piezoelectrics, the centered cylinder piezoelectrics 111 coaxial tubular piezoelectrics with minimum diameter that are positioned at, Prague acoustic reflection layer 4 is that the high impedance layer 41 of 1/4th wave length of sounds and low impedance layers 42 that a plurality of thickness is 1/4th wave length of sounds are superimposed and form by a plurality of thickness, and high impedance layer 41 and low impedance layers 42 are overlapped into Prague acoustic reflection layer 4 according to the sequence alternate of low impedance layers-high impedance layer-low impedance layers-high impedance layer-low impedance layers-high impedance layer.
In the present embodiment, width of the width of the annular gap between the height of the ratio of the height of the wall thickness of tubular piezoelectrics 112 and tubular piezoelectrics 112, centered cylinder piezoelectrics 111 and tubular piezoelectrics 112, adjacent two the tubular piezoelectrics 112, the tubular piezoelectrics with minimum diameter and the annular gap between the centered cylinder piezoelectrics 111 etc. can be determined occurrence according to the scope that embodiment one provides in conjunction with concrete condition.
In the present embodiment, the material of high impedance layer 41 is tungsten or platinum etc., and the material of low impedance layers 42 is manganese or zinc oxide etc.
Among above-described embodiment one and the embodiment two, the film of supporting layer 3 for being fabricated from a silicon.
Among above-mentioned three embodiment, the material of substrate layer 2 is silicon; The material of piezoelectric thin film layer 11 is aluminium nitride (AlN) or for zinc oxide (ZnO) or for lead zirconate titanate (PZT) or for other piezoelectric.
Among above-mentioned three embodiment, centered cylinder piezoelectrics 111 can be designed to the cylindric piezoelectrics of solid construction, also it can be designed to the cylindric piezoelectrics of hollow-core construction, verify by finite element numerical analysis, show the cylindric piezoelectrics that adopt solid construction and adopt the cylindric piezoelectrics of hollow-core construction to be more or less the same generally about 1% (the cylindric piezoelectrics of solid construction are better than the cylindric piezoelectrics of hollow-core construction) in the combination property of piezo-electric resonator.
Claims (10)
1. piezo-electric resonator, comprise the service area, described service area is by piezoelectric thin film layer and be formed at the last metal electrode on the upper surface of described piezoelectric thin film layer and the following metal electrode that is formed on the lower surface of described piezoelectric thin film layer is formed, it is characterized in that described piezoelectric thin film layer is made up of the tubular piezoelectrics that centered cylinder piezoelectrics and a plurality of diameter of equal altitudes has nothing in common with each other, coaxial large diameter described tubular piezoelectrics, the coaxial described tubular piezoelectrics with minimum diameter that are positioned at of described centered cylinder piezoelectrics of being positioned at of the described tubular piezoelectrics of minor diameter.
2. a kind of piezo-electric resonator according to claim 1 is characterized in that described centered cylinder piezoelectrics are solid cylindric piezoelectrics or are hollow cylindric piezoelectrics.
3. a kind of piezo-electric resonator according to claim 1 and 2, the wall thickness that it is characterized in that described tubular piezoelectrics is (0.5～1.5) with the ratio of the height of described tubular piezoelectrics: 1.
4. a kind of piezo-electric resonator according to claim 3 is characterized in that the height of described centered cylinder piezoelectrics and described tubular piezoelectrics is 0.5～4 μ m.
5. a kind of piezo-electric resonator according to claim 4, the width that it is characterized in that the annular gap between adjacent two described tubular piezoelectrics is 0.2～0.5 μ m, and having the described tubular piezoelectrics of minimum diameter and the width of the annular gap between the described centered cylinder piezoelectrics is 0.2～0.5 μ m.
6. a kind of piezo-electric resonator according to claim 5 is characterized in that described annular gap is by air or non-piezoelectric material filling.
7. a kind of piezo-electric resonator according to claim 6, the external diameter that it is characterized in that having the described tubular piezoelectrics of maximum gauge is 50 μ m～200 μ m.
8. a kind of piezo-electric resonator according to claim 7, it is characterized in that this piezo-electric resonator also comprise substrate layer and be arranged at described substrate layer and described service area between supporting layer, described substrate layer offers the air gap along the lower surface that short transverse extends to described supporting layer, described air gap makes the lower surface of described supporting layer directly contact with air, and acoustic wave energy is limited in the described service area.
9. a kind of piezo-electric resonator according to claim 7, it is characterized in that this piezo-electric resonator also comprise substrate layer and be arranged at described substrate layer and described service area between supporting layer, the top of described substrate layer offers air-gap, described air-gap makes the lower surface of described supporting layer directly contact with air, and acoustic wave energy is limited in the described service area.
10. a kind of piezo-electric resonator according to claim 7, it is characterized in that this piezo-electric resonator also comprise substrate layer and be arranged at described substrate layer and described service area between and be used for acoustic wave energy is limited in Prague acoustic reflection layer in the described service area, described Prague acoustic reflection layer is that the high impedance layer of 1/4th wave length of sounds and low impedance layers that a plurality of thickness is 1/4th wave length of sounds are superimposed and form by a plurality of thickness.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN 201320011344 CN203071889U (en) | 2013-01-09 | 2013-01-09 | Piezoelectric resonator |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201320011344 CN203071889U (en) | 2013-01-09 | 2013-01-09 | Piezoelectric resonator |
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| CN203071889U true CN203071889U (en) | 2013-07-17 |
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| CN 201320011344 Expired - Fee Related CN203071889U (en) | 2013-01-09 | 2013-01-09 | Piezoelectric resonator |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103117724A (en) * | 2013-01-09 | 2013-05-22 | 宁波大学 | Piezoelectric resonator |
| CN105004930A (en) * | 2014-04-23 | 2015-10-28 | 华南师范大学 | Novel microwave detection method and device, and application of method |
-
2013
- 2013-01-09 CN CN 201320011344 patent/CN203071889U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103117724A (en) * | 2013-01-09 | 2013-05-22 | 宁波大学 | Piezoelectric resonator |
| CN103117724B (en) * | 2013-01-09 | 2016-12-28 | 宁波大学 | A kind of piezo-electric resonator |
| CN105004930A (en) * | 2014-04-23 | 2015-10-28 | 华南师范大学 | Novel microwave detection method and device, and application of method |
| CN105004930B (en) * | 2014-04-23 | 2018-06-29 | 华南师范大学 | A kind of novel microwave sounding method and device and application |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130717 Termination date: 20170109 |