Bulk acoustic wave device with reduced non-linearities

Patent metadata

Field	Value
Publication number	US-12456958-B2
Application number	US-202017606626-A
Country	US
Kind code	B2
Filing date	Apr 23, 2020
Priority date	Apr 30, 2019
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

A BAW device comprises a first BAW resonator ( 1 ) and a second BAW resonator ( 2 ). The first BAW resonator and the second BAW resonator each comprise a first electrode ( 11, 21 ), a second electrode ( 12, 22 ) and a piezoelectric layer ( 13, 23 ) being arranged in each case between the first electrode and the second electrode of the associated BAW resonator. The first electrodes, the second electrodes and the piezoelectric layers of both BAW resonators are designed essentially identically. A first conductor track ( 24 ) extends from the first electrode of the second BAW resonator to a third electric element ( 3 ) of the BAW device and electrically connects said first electrode with said third electric element. A first dummy conductor track ( 14 ) extends from the first electrode of the first BAW resonator, is electrically connected to said first electrode and, apart from said first electrode, is not electrically connected to any further electric element. The first dummy conductor track is designed such that it influences the acoustic and capacitive properties of the first BAW resonator essentially in the same way as the first conductor track influences the acoustic and capacitive properties of the second BAW resonator.

First claim

The invention claimed is:

1. A BAW device, comprising:
a first BAW resonator; and
a second BAW resonator, wherein:
the first BAW resonator and the second BAW resonator each comprise a first electrode, a second electrode, and a piezoelectric layer, the piezoelectric layer of the associated BAW resonator being arranged in each case between the first electrode and the second electrode of the associated BAW resonator,
a first conductor track extends from the first electrode of the second BAW resonator to a third electric element of the BAW device and electrically connects said first electrode of the second BAW resonator with said third electric element,
a first dummy conductor track extends from the first electrode of the first BAW resonator and is electrically connected to said first electrode of the first BAW resonator,
in a top view, the first dummy conductor track overlaps with the second electrode of the first BAW resonator in a first overlap region, and
in the top view, the first conductor track overlaps with the second electrode of the second BAW resonator in a second overlap region.

2. The BAW device according to claim 1 , wherein:
in the top view, the first electrode of the first BAW resonator together with a second conductor track extending from the first electrode of the first BAW resonator and the first dummy conductor track overlap with the second electrode of the first BAW resonator in a third overlap region,
in the top view, the first electrode of the second BAW resonator together with the first conductor track and a third conductor track extending from the first electrode of the second BAW resonator overlap with the second electrode of the second BAW resonator in a fourth overlap region.

3. The BAW device according to claim 1 , wherein the first dummy conductor track extends starting from and in a direction away from the first electrode of the first BAW resonator over a length of at least 0.5 μm.

4. The BAW device according to claim 2 , wherein;
the second conductor track extends from the first electrode of the first BAW resonator to a fourth electric element of the BAW device and electrically connects said first electrode of the first BAW resonator with said fourth electric element, and
the third conductor track extends from the first electrode of the second BAW resonator to a fifth electric element of the BAW device and electrically connects said first electrode of the second BAW resonator with said fifth electric element.

5. The BAW device according to claim 1 , wherein;
the third electric element is a third BAW resonator comprising a first electrode, a second electrode and a piezoelectric layer being arranged between the first electrode and the second electrode of said third BAW resonator, and
the first conductor track electrically connects the first electrode of the second BAW resonator with the first electrode of the third BAW resonator.

6. The BAW device according to claim 5 , wherein the third BAW resonator is a shunt resonator.

7. The BAW device according to claim 1 , wherein the third electric element is an electric terminal or an inductance or a capacitor.

8. The BAW device according to claim 1 , wherein the first BAW resonator and the second BAW resonator are cascaded in anti-series.

9. The BAW device according to claim 1 , wherein the first BAW resonator and the second BAW resonator are cascaded in anti-parallel.

10. BAW device according to claim 1 , wherein the first and the second BAW resonators are both solidly mounted BAW resonators or are both film BAW resonators.

11. The BAW device according to claim 1 , wherein the first electrodes and the second electrodes of the first and the second BAW resonator each have a rectangular shape.

12. The BAW device according to claim 11 , wherein:
a transverse edge of the first electrode of the first BAW resonator faces a transverse edge of the first electrode of the second BAW resonator, and
the first dummy conductor track and the first conductor track each extend from longitudinal edges of the associated first electrodes, said longitudinal edges running perpendicularly to said transverse edges.

13. The BAW device according to claim 1 , wherein the first and the second BAW resonator each have a resonant frequency of at least 1 GHz.

14. The BAW device according to claim 1 , wherein the piezoelectric layers of the first and second BAW resonator are integrally formed with each other.

Assignees

• Rf360 Singapore Pte Ltd

Inventors

• Schiek Maximilian
• Aigner Willi
• Mittermaier Thomas

Classifications

• H03H9/542

  including passive elements (H03H9/545 takes precedence) · CPC title

• H03H9/171

  implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type · CPC title

• H03H9/132

  characterized by a particular shape · CPC title

• H03H9/02157

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

• H03H9/564

  implemented with thin-film techniques · CPC title