CN117833861A - Multilayer thin film resonator structure for high-performance surface acoustic wave filter - Google Patents
Multilayer thin film resonator structure for high-performance surface acoustic wave filter Download PDFInfo
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- CN117833861A CN117833861A CN202311729039.2A CN202311729039A CN117833861A CN 117833861 A CN117833861 A CN 117833861A CN 202311729039 A CN202311729039 A CN 202311729039A CN 117833861 A CN117833861 A CN 117833861A
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- surface acoustic
- acoustic wave
- thin film
- layer
- wave filter
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- 238000010897 surface acoustic wave method Methods 0.000 title claims abstract description 20
- 239000010409 thin film Substances 0.000 title claims abstract description 15
- 239000000463 material Substances 0.000 claims abstract description 30
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 claims abstract description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- 239000010949 copper Substances 0.000 claims description 7
- 229910013641 LiNbO 3 Inorganic materials 0.000 claims description 4
- 235000012239 silicon dioxide Nutrition 0.000 claims description 4
- 239000000377 silicon dioxide Substances 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- 230000008021 deposition Effects 0.000 claims description 2
- 239000000758 substrate Substances 0.000 abstract description 8
- 230000008878 coupling Effects 0.000 abstract description 6
- 238000010168 coupling process Methods 0.000 abstract description 6
- 238000005859 coupling reaction Methods 0.000 abstract description 6
- 238000000034 method Methods 0.000 abstract description 5
- 238000004613 tight binding model Methods 0.000 abstract description 2
- 239000010936 titanium Substances 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Abstract
The invention discloses a multilayer thin film resonator structure for a high-performance surface acoustic wave filter, wherein an interdigital electrode layer, a piezoelectric layer, an acoustic Bragg reflection layer and a substrate layer are laminated from top to bottom in the whole structure. The invention optimally designs the orientation angle selection of the piezoelectric layer lithium niobate by adopting a green function method based on Maxwell equation and Newton equation; the clutter mode can be effectively inhibited, the energy is concentrated, and the loss is reduced by optimizing and selecting the parameters of the impedance ratio of the high-impedance layer material; the optimized structure has a center frequency of 3.8GHz, an electromechanical coupling coefficient of higher than 18.3%, a phase velocity of 6400m/s, a high quality factor Q and good temperature characteristics.
Description
Technical Field
The invention relates to the technical field of surface acoustic wave devices, in particular to a multilayer thin film resonator structure for a high-performance surface acoustic wave filter.
Background
In recent years, with the advent of the 5G communications era, the electromagnetic wave band has been continuously increased, and meanwhile, the 5G communications technology uses the mimo antenna array technology on a large scale, which means that a filter, which is an important component of the radio frequency front end, is one of the fastest growing components. Filters used in mobile communication terminals are mainly surface acoustic wave filters and bulk acoustic wave filters. To meet these new functional and band requirements, acoustic filters are required to have lower insertion loss, steeper transition band characteristics, higher temperature stability, higher power tolerance, extended operating frequency range, higher linearity, smaller volume, and higher integration.
The main methods for improving the Q value of SAW devices and improving TCF performance at present are as follows: optimizing the orientation angle of the substrate, improving the electrode structure, improving the material performance, combining heterogeneous materials, and the like. For example, temperature compensated SAW (TC-SAW) has not only good TCF performance but also a high Q value. Acoustic plate wave (acoustic plate wave) devices have high acoustic wave propagation velocity and large electromechanical coupling coefficient (K 2 ). In addition, japanese village field company proposed a method of using (90 °,90 °,40 °) LiNbO 3 The bandwidth of the high-performance acoustic resonator formed by combining the acoustic Bragg reflector formed by the high-low acoustic impedance materials and the Si substrate is 9.5% (about 3 times larger than that of the traditional TC-SAW), and the phase speed is 6035m/s (about 1.5 times higher than that of the traditional TC-SAW). However, the optimal design of the piezoelectric sheet with the structure, the selection of the acoustic impedance material and the substrate material are not reported, and the Q value is still to be further improved.
Disclosure of Invention
The invention aims to solve the technical problems of providing a multilayer thin film resonator structure for a high-performance surface acoustic wave filter, providing the optimal design of the orientation angle of a piezoelectric substrate of the multilayer structure, selecting acoustic impedance materials and base materials, and designing the surface acoustic wave resonator with high Q value and good TCF.
In order to solve the above technical problems, the present invention provides a multilayer thin film resonator structure for a high performance surface acoustic wave filter, which is laminated from top to bottom: an interdigital electrode layer, a piezoelectric layer, an acoustic Bragg reflection layer and a base layer;
wherein, the interdigital electrode layer material is aluminum Al, and the standardized thickness is 0.08um.
Wherein the piezoelectric layer material is lithium niobate LiNbO 3 The normalized thickness is 0.2λ, λ being the surface acoustic wave wavelength.
Wherein the piezoelectric layer material is lithium niobateLiNbO 3 The orientation angle of (1) is (90 °,90 °,45 °).
Wherein the acoustic Bragg reflection layer is formed by overlapping deposition of high and low impedance materials.
Wherein the low-impedance layer material is silicon dioxide SiO 2 The thickness is one quarter wavelength.
Wherein the high-impedance layer is copper Cu, and has a thickness of between one quarter of transverse wave wavelength and one quarter of longitudinal wave wavelength (V S /4f～V L And/4 f), the optimal choice of the material of the high-resistance layer is determined by its modulus of elasticity and density.
Wherein the substrate layer material comprises Si and 6H-SiC, and the standardized thickness is 3λ.
The beneficial effects of the invention are as follows: the invention optimally designs the orientation angle selection of the piezoelectric layer lithium niobate by adopting a green function method based on Maxwell equation and Newton equation; the clutter mode can be effectively inhibited, the energy is concentrated, and the loss is reduced by optimizing and selecting the parameters of the impedance ratio of the high-impedance layer material; the optimized structure has a center frequency of 3.8GHz, an electromechanical coupling coefficient of higher than 18.3%, a phase velocity of 6400m/s, a high quality factor Q and good temperature characteristics.
Drawings
Fig. 1 (a) is a schematic diagram of a resonator according to the present invention.
Fig. 1 (b) is a schematic diagram of the structure of the acoustic bragg reflection layer of the present invention.
FIG. 2 is a graph of the change in wave velocity of the free and metallized surfaces of the piezoelectric layer according to the present invention and the electromechanical coupling coefficient as a function of propagation angle.
Fig. 3 is a graph showing propagation loss of a piezoelectric layer according to the present invention as a function of propagation angle.
Detailed Description
As shown in fig. 1 (a) and 1 (b), a multilayer thin film resonator structure for a high performance surface acoustic wave filter, comprising: a piezoelectric layer 2, an acoustic bragg reflection layer 3 with high and low impedance materials overlapping, a base layer 4 and an interdigital electrode layer 1.
The piezoelectric layer material is lithium niobate (LiNbO) 3 ) The thickness is as follows: 0.2λ; the low-impedance material is silicon dioxide (SiO) 2 ) The thickness is one quarter wavelength; the high-impedance material comprises titanium (Ti), silver (Ag), copper (Cu), nickel (Ni), molybdenum (Mo), gold (Au), platinum (Pt), titanium (Ta), tungsten (W), iridium (Ir) and the thickness range is V S /4f～V L 4f; the substrate layer is made of 6H-SiC, and the standardized thickness is 3λ; the interdigital electrode is Al, and the standardized thickness is 0.08um.
LiNbO of lithium niobate for piezoelectric substrate 3 By green's method and matrix-division, and analyzing the phase velocity, attenuation and electromechanical coupling coefficient K on free and metallized surfaces of LLSAWs on LN film plates 2 . As shown in fig. 2 and 3, liNbO can be selected (90 °,90 °,45 °) for comparative preference 3 To obtain a high K 2 And low loss.
For selective analysis of high impedance materials, the acoustic impedance ratio of the high impedance layer to the low impedance layer and the effect of high impedance layer thickness on SAW resonator structural parameters were analyzed. As the acoustic impedance ratio of the high impedance layer and the low impedance layer increases, the fractional bandwidth of the resonator increases slowly without significant change in the center frequency. When Ti, mo and Au materials are selected, more acoustic modes are excited due to their low density or extremely low elastic modulus. In addition, for the thickness of the high-resistance layer, from V S 4f to V L And/4 f, while the fractional bandwidth varies slightly with increasing high impedance layer thickness and shifts to lower frequencies, the additional spurious modes and modes that would degrade the LLSAWs response are suppressed.
According to calculation, when the high-impedance material is Cu, the optimized resonator has a center frequency of 3.8GHz, an electromechanical coupling coefficient of higher than 18.3%, a phase velocity of 6400m/s, a quality factor Q value of 2423 and good temperature characteristics.
Claims (8)
1. A multilayer thin film resonator structure for a high performance surface acoustic wave filter, characterized in that an interdigital electrode layer, a piezoelectric layer, an acoustic bragg reflection layer, and a base layer are laminated from top to bottom in the overall structure.
2. The multilayer thin film resonator structure for a high performance surface acoustic wave filter according to claim 1, wherein the interdigital electrode layer material is aluminum Al, and the normalized thickness thereof is 0.08um.
3. The multilayer thin film resonator structure for a high performance surface acoustic wave filter according to claim 1, wherein the piezoelectric layer material is lithium niobate LiNbO 3 The normalized thickness is 0.2λ, λ being the surface acoustic wave wavelength.
4. The multilayer thin film resonator structure for a high performance surface acoustic wave filter according to claim 3, wherein the piezoelectric layer material is lithium niobate LiNbO 3 The orientation angle of (1) is (90 °,90 °,45 °).
5. The multilayer thin film resonator structure for a high performance surface acoustic wave filter of claim 1, wherein the acoustic bragg reflector layer is formed by overlapping deposition of high and low impedance materials.
6. The multilayer thin film resonator structure for a high performance surface acoustic wave filter of claim 5, wherein the low impedance layer material is silicon dioxide, siO 2 The thickness is one quarter wavelength.
7. The multilayer thin film resonator structure for a high performance surface acoustic wave filter according to claim 5, wherein the high impedance layer is copper Cu, and has a thickness of between a quarter of a transverse wave wavelength and a quarter of a longitudinal wave wavelength (V S /4f～V L And/4 f), the optimal choice of the material of the high-resistance layer is determined by its modulus of elasticity and density.
8. The multilayer thin film resonator structure for a high performance surface acoustic wave filter according to claim 1, wherein the base layer material comprises Si and 6H-SiC, which have a normalized thickness of 3λ.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311729039.2A CN117833861A (en) | 2023-12-15 | 2023-12-15 | Multilayer thin film resonator structure for high-performance surface acoustic wave filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311729039.2A CN117833861A (en) | 2023-12-15 | 2023-12-15 | Multilayer thin film resonator structure for high-performance surface acoustic wave filter |
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| Publication Number | Publication Date |
|---|---|
| CN117833861A true CN117833861A (en) | 2024-04-05 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311729039.2A Pending CN117833861A (en) | 2023-12-15 | 2023-12-15 | Multilayer thin film resonator structure for high-performance surface acoustic wave filter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117833861A (en) |
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2023
- 2023-12-15 CN CN202311729039.2A patent/CN117833861A/en active Pending
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