CN-122001325-A - Acoustic wave resonator and manufacturing method thereof

CN122001325ACN 122001325 ACN122001325 ACN 122001325ACN-122001325-A

Abstract

The invention provides an acoustic wave resonator and a manufacturing method thereof, relating to the technical field of radio frequency devices, wherein the acoustic wave resonator comprises a first electrode, a second electrode and a piezoelectric layer arranged between the first electrode and the second electrode; the first electrode is arranged at the bottom of the piezoelectric layer, the second electrode is arranged at the top of the piezoelectric layer, the piezoelectric layer is a composite piezoelectric layer, the composite piezoelectric layer comprises a first sub-piezoelectric layer and a second sub-piezoelectric layer, and the first sub-piezoelectric layer and the second sub-piezoelectric layer have opposite piezoelectric polarities. The invention can effectively improve the working frequency of the acoustic wave resonator on the premise of not sacrificing key performance indexes.

Inventors

HUANG YUANQING
ZHANG WEI
JIANG XINGYONG
WANG XULIANG
ZHENG ZHIQIANG
ZHANG LANYUE
HAO LONG

Assignees

诺思(天津)微系统有限责任公司

Dates

Publication Date: 20260508
Application Date: 20260116

Claims (12)

1. The acoustic wave resonator is characterized by comprising a first electrode, a second electrode and a piezoelectric layer, wherein the piezoelectric layer is arranged between the first electrode and the second electrode; the piezoelectric layer is a composite piezoelectric layer, and the composite piezoelectric layer comprises a first sub-piezoelectric layer and a second sub-piezoelectric layer; the first and second sub-piezoelectric layers have opposite piezoelectric polarities.
2. The acoustic wave resonator according to claim 1, further comprising a dielectric layer; the dielectric layer is disposed between the first sub-piezoelectric layer and the second sub-piezoelectric layer.
3. The acoustic wave resonator according to claim 1, further comprising a substrate, an acoustic mirror, and a protective layer; The acoustic mirror is disposed between the first electrode and the substrate; The protective layer is disposed on top of the second electrode.
4. The acoustic wave resonator according to claim 3, further comprising a seed layer; the seed layer is disposed between the first electrode and the substrate.
5. A sound wave resonator according to claim 3, characterized in that the acoustic mirror is a cavity or a bragg reflecting layer.
6. The acoustic wave resonator according to claim 3, further comprising a cantilever structure and/or a bump structure; The cantilever structure is arranged at least one of the following positions: Between the piezoelectric layer and the second electrode, between the second electrode and the protective layer, between the first sub-piezoelectric layer and the second sub-piezoelectric layer, between the piezoelectric layer and the first electrode, between the first electrode and the substrate; the raised structure is disposed in at least one of the following positions: The piezoelectric layer is arranged between the second electrode, the second electrode and the protective layer, the first sub-piezoelectric layer and the second sub-piezoelectric layer, the piezoelectric layer and the first electrode, and the first electrode and the substrate.
7. The acoustic wave resonator of claim 6, further comprising a recessed structure; the recessed structure is disposed in at least one of the following locations: Between the second electrode and the protective layer, between the first sub-piezoelectric layer and the second sub-piezoelectric layer, between the piezoelectric layer and the first electrode, between the piezoelectric layer and the second electrode, between the first electrode and the substrate.
8. The acoustic wave resonator according to claim 1, further comprising a metal layer; The metal layer is disposed between the first sub-piezoelectric layer and the second sub-piezoelectric layer.
9. The acoustic wave resonator according to claim 1, wherein the composite piezoelectric layer further comprises other sub-piezoelectric layers than the first sub-piezoelectric layer and the second sub-piezoelectric layer, the piezoelectric polarities of any adjacent sub-piezoelectric layers being opposite.
10. A method of manufacturing an acoustic wave resonator, comprising: sequentially forming a first sub-piezoelectric layer and a second sub-piezoelectric layer with opposite electric polarity to the first sub-piezoelectric layer on a temporary substrate, wherein the first sub-piezoelectric layer and the second sub-piezoelectric layer form a composite piezoelectric layer; forming a first electrode on a surface of the second sub-piezoelectric layer; Removing the temporary substrate; And forming a second electrode on the exposed surface of the first sub-piezoelectric layer.
11. The method of manufacturing an acoustic wave resonator according to claim 10, characterized in that after forming the first electrode on the surface of the second sub-piezoelectric layer, further comprising: A final substrate with an acoustic mirror is provided and the composite piezoelectric layer with the first electrode formed is bonded to the final substrate.
12. The method of manufacturing an acoustic wave resonator according to claim 10, characterized by further comprising, after said forming a second electrode on the exposed surface of said first sub-piezoelectric layer: And forming a protective layer on the surface of the second electrode.

Description

Acoustic wave resonator and manufacturing method thereof Technical Field The invention relates to the technical field of radio frequency devices, in particular to an acoustic wave resonator and a manufacturing method thereof. Background As wireless communication technology advances toward higher frequency bands, such as X-band, ku-band, K-band, etc., higher performance requirements, including higher operating frequencies, higher Q (Quality Factor) and larger transverse electromechanical coupling coefficients, are imposed on core devices, i.e., resonators, in radio frequency front-ends。 Thin film bulk acoustic resonators are a common type of acoustic resonator. In the conventional thin film bulk acoustic resonator, the operating frequency is mainly determined by the thickness of the piezoelectric film thereof, and the higher the operating frequency is, the thinner the thickness of the piezoelectric film is required. When the operating frequency exceeds 8GHz, the preparation of an ultra-thin piezoelectric film with high quality presents a great challenge in the process, which severely restricts the further increase of the operating frequency of the resonator. To break through this physical limitation, one possible idea is to work with the higher harmonic modes inherent to the resonator, such as the frequency doubling or frequency tripled modes. However, the excitation efficiency of higher harmonics is usually low, resulting in performance problems of small transverse electromechanical coupling coefficient, low quality factor, high series resistance, and the like of the resonator. Therefore, how to effectively increase the working frequency of the acoustic wave resonator without sacrificing key performance indexes becomes a technical problem to be solved. Disclosure of Invention In view of the above, the present invention provides an acoustic wave resonator and a method for manufacturing the same. The invention adopts the following technical scheme: In a first aspect, the invention provides an acoustic wave resonator, comprising a first electrode, a second electrode and a piezoelectric layer arranged between the first electrode and the second electrode, wherein the first electrode is arranged at the bottom of the piezoelectric layer, and the second electrode is arranged at the top of the piezoelectric layer; the piezoelectric layer is a composite piezoelectric layer, and the composite piezoelectric layer comprises a first sub-piezoelectric layer and a second sub-piezoelectric layer; the first and second sub-piezoelectric layers have opposite piezoelectric polarities. Optionally, the acoustic wave resonator of the invention further comprises a dielectric layer; the dielectric layer is disposed between the first sub-piezoelectric layer and the second sub-piezoelectric layer. Optionally, the acoustic wave resonator of the invention further comprises a substrate, an acoustic mirror and a protective layer; The acoustic mirror is disposed between the first electrode and the substrate; The protective layer is disposed on top of the second electrode. Optionally, the acoustic wave resonator of the present invention further comprises a seed layer; the seed layer is disposed between the first electrode and the substrate. Optionally, the acoustic mirror is a cavity or a bragg reflective layer. Optionally, the acoustic wave resonator of the invention further comprises a suspension wing structure and/or a bulge structure; The cantilever structure is arranged at least one of the following positions: Between the piezoelectric layer and the second electrode, between the second electrode and the protective layer, between the first sub-piezoelectric layer and the second sub-piezoelectric layer, between the piezoelectric layer and the first electrode, between the first electrode and the substrate; the raised structure is disposed in at least one of the following positions: The piezoelectric layer is arranged between the second electrode, the second electrode and the protective layer, the first sub-piezoelectric layer and the second sub-piezoelectric layer, the piezoelectric layer and the first electrode, and the first electrode and the substrate. Optionally, the acoustic wave resonator of the present invention further comprises a concave structure; the recessed structure is disposed in at least one of the following locations: Between the second electrode and the protective layer, between the first sub-piezoelectric layer and the second sub-piezoelectric layer, between the piezoelectric layer and the first electrode, between the piezoelectric layer and the second electrode, between the first electrode and the substrate. Optionally, the acoustic wave resonator further comprises a metal layer; The metal layer is disposed between the first sub-piezoelectric layer and the second sub-piezoelectric layer. Optionally, the composite piezoelectric layer further includes other sub-piezoelectric layers besides the first sub-piezoelectric lay