BAW resonators with antisymmetric thick electrodes

Patent metadata

Field	Value
Publication number	US-10879872-B2
Application number	US-201916389806-A
Country	US
Kind code	B2
Filing date	Apr 19, 2019
Priority date	Apr 19, 2019
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A resonator circuit device. This device can include a piezoelectric layer having a front-side electrode and a back-side electrode spatially configured on opposite sides of the piezoelectric layer. Each electrode has a connection region and a resonator region. Each electrode also includes a partial mass-loaded structure configured within a vicinity of its connection region. The front-side electrode and the back-side electrode are spatially configured in an anti-symmetrical manner with the resonator regions of both electrodes at least partially overlapping and the first and second connection regions on opposing sides. This configuration provides a symmetric acoustic impedance profile for improved Q factor and can reduce the issues of misalignment or unbalanced boundary conditions associated with conventional single mass-loaded perimeter configurations.

First claim

What is claimed is:

1. A resonator circuit device comprising:
a piezoelectric layer;
a front-side electrode formed overlying the piezoelectric layer, the front-side electrode having a first connection region and a first resonator region, the front-side electrode having a first partial mass-loaded structure configured within a vicinity of the first connection region; and
a back-side electrode formed underlying the piezoelectric layer, the back-side electrode having a second connection region and a second resonator region, the back-side electrode having a second partial mass-loaded structure configured within a vicinity of the second connection region;
wherein the front-side electrode and the back-side electrode are spatially configured in an anti-symmetrical manner with the first and second resonator regions at least partially overlapping and the first and second connection regions on opposing sides.

2. The device of claim 1 wherein the front-side electrode and back-side electrode include molybdenum (Mo), ruthenium (Ru), tungsten (W), or aluminum-copper (AlCu).

3. The device of claim 2 wherein the first and second partial mass-loaded structures include molybdenum (Mo), ruthenium (Ru), tungsten (W), or aluminum-copper (AlCu).

4. The device of claim 1 wherein the front-side and back-side electrodes are spatially configured such that a portion of the first partial mass-loaded structure overlaps a portion of the second resonator region and a portion of the first resonator region overlaps a portion of the second partial mass-loaded structure.

5. The device of claim 1 wherein the first partial mass-loaded structure is spatially configured around about half of a perimeter of the front-side electrode on the side of the first connection region, and wherein the second partial mass-loaded structure is spatially configured around about half of a perimeter of the back-side electrode on the side of the second connection region.

6. The device of claim 1 wherein the piezoelectric layer includes materials or alloys having at least one of the following: AlN, AlGaN, GaN, ScAlN, LiNbO3, LiTaO3, Ba(Sr,Ti)O3, and Pb(Zr,Ti)O3.

7. A resonator circuit device comprising:
a piezoelectric layer;
a front-side electrode formed overlying the piezoelectric layer, the front-side electrode having a first connection region and a first resonator region, the front-side electrode having a first thicker portion within a vicinity of the first connection region; and
a back-side electrode formed underlying the piezoelectric layer, the back-side electrode having a second connection region and a second resonator region, the back-side electrode having a second thicker portion within a vicinity of the second connection region;
wherein the front-side electrode and the back-side electrode are spatially configured in an anti-symmetrical manner with the first and second resonator regions at least partially overlapping and the first and second connection regions on opposing sides.

8. The device of claim 7 wherein the front-side electrode and back-side electrode include molybdenum (Mo), ruthenium (Ru), tungsten (W), or aluminum-copper (AlCu).

9. The device of claim 7 wherein the front-side and back-side electrodes are spatially configured such that a portion of the first thicker portion overlaps a portion of the second resonator region and a portion of the second thicker portion overlaps a portion of the first resonator region.

10. The device of claim 7 wherein the first thicker portion is spatially configured around about half of a perimeter of the front-side electrode on the side of the first connection region, and wherein the second thicker portion is spatially configured around about half of a perimeter of the back-side electrode on the side of the second connection region.

11. The device of claim 7 wherein the piezoelectric layer includes materials or alloys having at least one of the following: AlN, AlGaN, GaN, ScAlN, LiNbO3, LiTaO3, Ba(Sr,Ti)O3, and Pb(Zr,Ti)O3.

12. An RF filter circuit device comprising:
a substrate member having a cavity region;
a piezoelectric layer formed overlying the substrate member;
a front-side electrode formed overlying the piezoelectric layer, the front-side electrode having a first connection region and a first resonator region, the front-side electrode having a first partial mass-loaded structure configured within a vicinity of the first connection region;
a back-side electrode formed underlying the piezoelectric layer within the cavity region, the back-side electrode having a second connection region and a second resonator region, the back-side electrode having a second partial mass-loaded structure configured within a vicinity of the second connection region;
wherein the front-side electrode and the back-side electrode are spatially configured in an anti-symmetrical manner with the first and second resonator regions at least partially overlapping and the first and second connection regions on opposing sides;
a micro-via configured through a portion of the piezoelectric layer, the micro-via being electrically coupled to the back-side electrode at the second connection region;
a first bond pad electrically coupled to the front-side electrode at the first connection region; and
a second bond pad electrically coupled to the back-side electrode through the micro-via.

13. The device of claim 12 wherein the front-side electrode and back-side electrode include molybdenum (Mo), ruthenium (Ru), tungsten (W), or aluminum-copper (AlCu).

14. The device of claim 13 wherein the first and second partial mass-loaded structures include molybdenum (Mo), ruthenium (Ru), tungsten (W), or aluminum-copper (AlCu).

15. The device of claim 12 wherein the front-side and back-side electrodes are spatially configured such that a portion of the first partial mass-loaded structure overlaps a portion of the second resonator region and a portion of the second partial mass-loaded structure overlaps a portion of the first resonator region.

16. The device of claim 12 wherein the first partial mass-loaded structure is spatially configured around about half of a perimeter of the front-side electrode on the side of the first connection region, and wherein the second partial mass-loaded structure is spatially configured around about half of a perimeter of the back-side electrode on the side of the second connection region.

17. The device of claim 12 wherein the piezoelectric layer includes materials or alloys having at least one of the following: AlN, AlGaN, GaN, ScAlN, LiNbO3, LiTaO3, Ba(Sr,Ti)O3, and Pb(Zr,Ti)O3.

18. The device of claim 12 wherein the micro-via includes gold, aluminum, or copper.

19. The device of claim 12 further comprising a cap layer formed overlying the front-side electrode, the piezoelectric layer, the back-side electrode, and the substrate member; wherein the cap layer includes a transfer substrate, a glass substrate, a silicon substrate, a sapphire (Al2O3) substrate, or an interposer substrate.

20. The device of claim 19 wherein the cap layer includes a first cap via formed through a portion of the cap layer and electrically coupled to the first bond pad; wherein the cap layer includes a second cap via electrically coupled to the second bond pad; wherein the cap layer includes a first cap bond pad formed overlying the cap layer and electrically coupled to the first cap via; and wherein the cap layer includes a second cap bond pad formed overlying the cap layer and electrically coupled to the second cap via.

Assignees

• Akoustis Inc

Inventors

• Kim Dae Ho
• Winters Mary
• Bi Zhiqiang

Classifications

• H03H9/174

  Membranes · CPC title

• H03H9/132 Primary

  characterized by a particular shape · CPC title

• H03H9/02118

  of lateral leakage between adjacent resonators · CPC title

• H03H9/02157

  Dimensional parameters, e.g. ratio between two dimension parameters, length, width or thickness · CPC title

• H03H9/131

  consisting of a multilayered structure · CPC title