CN111342803A - Film bulk acoustic resonator - Google Patents
Film bulk acoustic resonator Download PDFInfo
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- CN111342803A CN111342803A CN202010223938.5A CN202010223938A CN111342803A CN 111342803 A CN111342803 A CN 111342803A CN 202010223938 A CN202010223938 A CN 202010223938A CN 111342803 A CN111342803 A CN 111342803A
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- 239000000758 substrate Substances 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 21
- 230000001939 inductive effect Effects 0.000 claims abstract description 16
- 230000004888 barrier function Effects 0.000 claims abstract description 9
- 239000010408 film Substances 0.000 claims description 18
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 3
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims description 3
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 3
- 239000010409 thin film Substances 0.000 claims description 3
- 230000006698 induction Effects 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 7
- 229910052710 silicon Inorganic materials 0.000 description 6
- 239000010703 silicon Substances 0.000 description 6
- 238000005530 etching Methods 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 230000005684 electric field Effects 0.000 description 3
- 230000010355 oscillation Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 230000001976 improved effect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000001039 wet etching Methods 0.000 description 2
- 241001391944 Commicarpus scandens Species 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000006855 networking Effects 0.000 description 1
- 230000021715 photosynthesis, light harvesting Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000008093 supporting effect Effects 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/178—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator of a laminated structure of multiple piezoelectric layers with inner electrodes
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02086—Means for compensation or elimination of undesirable effects
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02086—Means for compensation or elimination of undesirable effects
- H03H9/02102—Means for compensation or elimination of undesirable effects of temperature influence
Abstract
The present invention provides a film bulk acoustic resonator, comprising: the device comprises a substrate, a barrier layer, a base layer, an induction layer, a first electrode layer, a piezoelectric layer, a second electrode layer and an air gap; the barrier layer is formed on one surface of the substrate, and the surface of the substrate is provided with a lower concave cavity; the base layer is arranged on the surface of the substrate, and an air gap is formed in a concave cavity below the base layer; the inducing layer is grown on the substrate layer; and a second electrode layer, a piezoelectric layer and a first electrode layer are sequentially grown on the inducing layer from bottom to top. The material of the first electrode layer and the second electrode layer is selected to be Mo. The piezoelectric layer is made of AlN, and the thickness of the piezoelectric layer is one half of the wavelength of the sound wave corresponding to the resonance frequency. The invention can improve the mechanical strength and power capacity of the structure and meet the application of higher frequency.
Description
Technical Field
The invention relates to a film bulk acoustic wave filter for an electronic circuit, in particular to a film bulk acoustic resonator.
Background
Reducing the cost and size of electronic equipment is a continuing need for small devices for electronic devices. Consumer products, such as portable networking products like cell phones, will severely limit the size and cost of their internal devices. Based on the characteristics of high frequency, wide bandwidth and the like of the five-generation communication system, the radio frequency filter needs to meet higher requirements. Therefore, there is a continuous need for research and improvement to improve the production yield and reduce the production cost of the rf filter.
An important class of rf filters is bulk acoustic wave filters. The implementation of this filter function is based on bulk acoustic wave resonators. The bulk acoustic wave resonator uses a piezoelectric thin film material, and is sandwiched between two layers of metal electrodes to form an electrode-piezoelectric material-electrode sandwich structure. The piezoelectric material in the middle converts the electric energy into mechanical energy sound wave under the electrostatic action, and the sound wave longitudinally propagates along the direction of the electric field and in the reverse direction and forms mechanical resonance. Thus, a filtering function can be achieved. The method generally adopted is that the surfaces of the upper electrode and the lower electrode form an interface with air, so that sound waves are limited in the piezoelectric oscillation stack, and energy dissipation is reduced.
The film bulk acoustic resonator has the advantages of high Q value, small temperature coefficient, small volume, integration and the like. The basic film bulk acoustic resonator consists of a layer of piezoelectric material and two electrodes. In the research and development of the fifth generation communication technology, the communication frequency is developed towards high frequency, the structural thickness of a resonator device is thinner and thinner, the power capacity is reduced, and the mechanical strength is reduced.
For existing film bulk acoustic resonators;
the first structure adopts a process of back etching of silicon, namely, wet etching is carried out on the back of a silicon substrate, most structures of the silicon substrate are removed, and an air cavity is formed to form a suspended sandwich structure. The structure of the process is very fragile and easy to break, and a Si3N4 layer is generally required to grow before the lower electrode is deposited, so that the strength of the film is increased by the low-stress characteristic of the process. In addition, the back etching is performed using a wet etchant such as KOH, and since the wet etching is directional, there is a 54 degree slope, which severely limits the final density of the wafer and the FBAR throughput.
The second structure is improved on the first structure, a thin air gap is formed between the piezoelectric oscillation stack and the silicon substrate through a bulk silicon process, the structure of the silicon substrate is reserved, and the mechanical strength is guaranteed. Such an air gap allows to obtain a flat piezoelectric layer and a better structural stability, which is also one of the mainstream structures used in the current products. The structure has a good Q value, wherein the process for etching the air gap is complex, and an etching hole needs to be reserved in advance.
The third structure is called a solid stacked Resonator (SMR) structure, which uses a bragg reflector instead of an air gap structure. The Bragg reflection layer can generate large acoustic impedance at the bottom of the piezoelectric oscillation stack and is generally made of overlapped materials with high and low acoustic impedance, and the thickness of each layer is selected to be a quarter wavelength of the resonant frequency of the material. However, the structure can not form an independent and free film, the Q value is lower compared with a resonator with an air gap structure, the performance of the reflecting layer can be changed by different combinations of materials and the number of the reflecting layers, and the design is complex.
Disclosure of Invention
The invention provides a film bulk acoustic resonator, aiming at improving the mechanical strength and power capacity of a structure and meeting the application of higher frequency. The technical scheme adopted by the invention is as follows:
a thin film bulk acoustic resonator comprising: the device comprises a substrate, a barrier layer, a base layer, an induction layer, a first electrode layer, a piezoelectric layer, a second electrode layer and an air gap;
the barrier layer is formed on one surface of the substrate, and the surface of the substrate is provided with a lower concave cavity;
the base layer is arranged on the surface of the substrate, and an air gap is formed in a concave cavity below the base layer;
the inducing layer is grown on the substrate layer; and a second electrode layer, a piezoelectric layer and a first electrode layer are sequentially grown on the inducing layer from bottom to top.
Further, the material of the first electrode layer and the second electrode layer is selected to be Mo.
Further, the material of the piezoelectric layer is AlN, and the thickness is one half of the wavelength of the acoustic wave corresponding to the resonance frequency.
Furthermore, the material of the inducing layer is selected to be ALN, and the thickness of the inducing layer is less than or equal to one fourth of the wavelength of the sound wave corresponding to the resonant frequency.
Further, the material of the substrate layer is selected from monocrystalline silicon or polycrystalline silicon or amorphous silicon.
Further, the base layer has a thickness in the range of 100 angstroms to 1500 angstroms.
The invention has the advantages that: according to the film bulk acoustic resonator provided by the invention, a layer of AlN material and a supporting silicon structure (a substrate layer) are added on a classic sandwich structure, so that the resonator cannot be cracked due to the problem of mechanical fastness when working in a resonance state, and meanwhile, a heat dissipation passage is added, so that the power capacity of the resonator is improved, and the application of a higher-frequency filter is met.
Drawings
Fig. 1 is a schematic diagram of a basic structure of a conventional resonator.
Fig. 2 is a schematic structural diagram of the present invention.
Detailed Description
The invention is further illustrated by the following specific figures and examples.
The basic structure of the conventional film bulk acoustic resonator is shown in fig. 1, and is a sandwich structure, in which a piezoelectric layer 106 is sandwiched between a first electrode layer 107 and a second electrode layer 105; establishing an electric field on the piezoelectric layer 106, the piezoelectric material of the piezoelectric layer converting the electric energy into mechanical energy acoustic waves, the acoustic waves longitudinally propagating in the direction and the reverse direction of the electric field and forming mechanical resonance; this structure is the structural basis of each film bulk acoustic resonator.
As shown in fig. 2, the film bulk acoustic resonator provided in the embodiment of the present invention includes: the structure comprises a substrate 101, a barrier layer 102, a base layer 103, an inducing layer 104, a first electrode layer 107, a piezoelectric layer 106, a second electrode layer 105 and an air gap 108;
the barrier layer 102 is formed on one surface of the substrate 101, and the surface of the substrate 101 is provided with a lower cavity;
the base layer 103 is arranged on the one surface of the substrate 101, and an air gap 108 is formed in the cavity under the base layer 103;
the inducing layer 104 is grown on the base layer 103; a second electrode layer 105, a piezoelectric layer 106 and a first electrode layer 107 are grown on the inducing layer 104 from bottom to top in sequence;
in some embodiments, the material of the first electrode layer 107 and the second electrode layer 105 is selected to be Mo; the piezoelectric layer 106 is made of AlN, and the thickness of the piezoelectric layer is one half of the wavelength of the acoustic wave corresponding to the resonant frequency; a sandwich structure is formed, and the conversion of converting electric energy into mechanical wave sound waves is realized;
in some embodiments, the material of the inducing layer 104 is selected to be ALN, and the thickness is less than or equal to a quarter of the wavelength of the acoustic wave corresponding to the resonant frequency, for example, several tens of angstroms to a quarter of the wavelength of the acoustic wave corresponding to the resonant frequency; the inducing layer 104 is used for resonance absorption and inducing growth of the piezoelectric material of the piezoelectric layer 106, so that the loss of mechanical wave acoustic waves can be reduced;
in some embodiments, the material of the base layer 103 is selected to be monocrystalline silicon or polycrystalline silicon or amorphous silicon; the base layer 103 serves as a heat dissipation channel and compensates for the shift of the resonance frequency; the thickness of the base layer 103 is determined according to the requirement of resonance frequency compensation, and the thickness range is 100-1500 angstroms;
in some embodiments, the air gap 108 under the base layer 103 is formed by a dry etching process and a release process in a semiconductor process;
in some embodiments, the material of the barrier layer 102 is typically silicon oxide.
Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.
Claims (6)
1. A thin film bulk acoustic resonator, comprising: the device comprises a substrate (101), a barrier layer (102), a base layer (103), an inducing layer (104), a first electrode layer (107), a piezoelectric layer (106), a second electrode layer (105) and an air gap (108);
the barrier layer (102) is formed on one surface of the substrate (101), and a lower cavity is formed on the surface of the substrate (101);
the base layer (103) is arranged on the one surface of the substrate (101), and an air gap (108) is formed in a concave cavity below the base layer (103);
an inducing layer (104) is grown on the base layer (103); a second electrode layer (105), a piezoelectric layer (106) and a first electrode layer (107) are grown on the inducing layer (104) in sequence from bottom to top.
2. The film bulk acoustic resonator of claim 1,
the material of the first electrode layer (107) and the second electrode layer (105) is selected to be Mo.
3. The film bulk acoustic resonator of claim 1,
the piezoelectric layer (106) is made of AlN and has a thickness of one half of the wavelength of the acoustic wave corresponding to the resonance frequency.
4. The film bulk acoustic resonator of claim 1,
the material of the inducing layer (104) is selected to be ALN, and the thickness is less than or equal to one fourth of the wavelength of the sound wave corresponding to the resonant frequency.
5. The film bulk acoustic resonator of claim 1,
the material of the base layer (103) is selected from monocrystalline silicon, polycrystalline silicon or amorphous silicon.
6. The film bulk acoustic resonator of claim 1,
the base layer (103) has a thickness in the range of 100-1500 angstroms.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010223938.5A CN111342803A (en) | 2020-03-26 | 2020-03-26 | Film bulk acoustic resonator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010223938.5A CN111342803A (en) | 2020-03-26 | 2020-03-26 | Film bulk acoustic resonator |
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| Publication Number | Publication Date |
|---|---|
| CN111342803A true CN111342803A (en) | 2020-06-26 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010223938.5A Pending CN111342803A (en) | 2020-03-26 | 2020-03-26 | Film bulk acoustic resonator |
Country Status (1)
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI721934B (en) * | 2020-10-22 | 2021-03-11 | 台灣奈米碳素股份有限公司 | Method for manufacturing film bulk acoustic resonance device having specific resonant frequency |
| CN113395051A (en) * | 2021-07-09 | 2021-09-14 | 赛莱克斯微系统科技（北京）有限公司 | Film bulk acoustic resonator and high-frequency radio-frequency device |
| WO2024020769A1 (en) * | 2022-07-26 | 2024-02-01 | 京东方科技集团股份有限公司 | Bulk acoustic resonator and preparation method therefor, and electronic device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005236338A (en) * | 2001-05-11 | 2005-09-02 | Ube Ind Ltd | Piezoelectric thin-film resonator |
| CN102291095A (en) * | 2011-04-27 | 2011-12-21 | 庞慰 | complex acoustic wave resonator |
| CN107528561A (en) * | 2017-09-12 | 2017-12-29 | 电子科技大学 | A kind of cavity type FBAR and preparation method thereof |
-
2020
- 2020-03-26 CN CN202010223938.5A patent/CN111342803A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005236338A (en) * | 2001-05-11 | 2005-09-02 | Ube Ind Ltd | Piezoelectric thin-film resonator |
| CN102291095A (en) * | 2011-04-27 | 2011-12-21 | 庞慰 | complex acoustic wave resonator |
| CN107528561A (en) * | 2017-09-12 | 2017-12-29 | 电子科技大学 | A kind of cavity type FBAR and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 申洪霞等: "一种薄膜体声波谐振器的设计与验证", 《西安电子科技大学学报》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI721934B (en) * | 2020-10-22 | 2021-03-11 | 台灣奈米碳素股份有限公司 | Method for manufacturing film bulk acoustic resonance device having specific resonant frequency |
| CN113395051A (en) * | 2021-07-09 | 2021-09-14 | 赛莱克斯微系统科技（北京）有限公司 | Film bulk acoustic resonator and high-frequency radio-frequency device |
| CN113395051B (en) * | 2021-07-09 | 2024-03-26 | 赛莱克斯微系统科技（北京）有限公司 | Thin film bulk acoustic resonator and high-frequency radio-frequency device |
| WO2024020769A1 (en) * | 2022-07-26 | 2024-02-01 | 京东方科技集团股份有限公司 | Bulk acoustic resonator and preparation method therefor, and electronic device |
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Application publication date: 20200626 |
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| RJ01 | Rejection of invention patent application after publication |