Acoustic resonator comprising aluminum scandium nitride and temperature compensation feature

• US 9,590,165 B2
• Filed: 02/28/2014
• Issued: 03/07/2017
• Est. Priority Date: 03/29/2011
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Zou, Qiang, Feng, Chris, Nikkel, Phil, Grannen, Kevin J., Yeh, Tangshiun, Burak, Dariusz, Choy, John, Lamers, Tina L.
• Primary Examiner(s): Dougherty, Thomas
• Application Number:
  US14/194,074
• Publication Number:
  US 20140175950A1
• Time in Patent Office: 1,103 Days
• Field of Search: 310311-371, 333186-197, 252/62.9 PZ, 252/62.9 R, 501/134
• US Class Current: 1/1
• CPC Class Codes: H03H 9/02102 of temperature influence cutting angles H03H9/02015
• CPC Class Codes: H03H 9/131 consisting of a multilayered structure
• CPC Class Codes: H03H 9/173 Air-gaps
• CPC Class Codes: H10N 30/1051 based on piezoelectric or electrostrictive films or coatings

Abstract

An acoustic resonator structure comprises a first electrode disposed on a substrate, a piezoelectric layer disposed on the first electrode and comprising aluminum scandium nitride, a second electrode disposed on the piezoelectric layer, and a temperature compensation feature having a temperature coefficient offsetting at least a portion of a temperature coefficient of the piezoelectric layer, the first electrode, and the second electrode.

Claims

1. An acoustic resonator structure, comprising:

a first electrode disposed on a substrate;

a piezoelectric layer disposed on the first electrode and comprising aluminum scandium nitride;

a second electrode disposed on the piezoelectric layer; and

a temperature compensation feature having a temperature coefficient offsetting at least a portion of a temperature coefficient of the piezoelectric layer, the first electrode, or the second electrode; and

a planarization layer disposed over the substrate and abutting the first electrode, the planarization layer being substantially flush with the first electrode.

2. The acoustic resonator structure of claim 1, wherein the aluminum scandium nitride comprises about 3-10 wt % scandium.

3. The acoustic resonator structure of claim 1, wherein the temperature compensation feature comprises silicon oxide.

4. The acoustic resonator structure of claim 1, wherein the temperature compensation feature comprises a temperature compensation layer disposed between the first electrode and the piezoelectric layer.

5. The acoustic resonator structure of claim 4, further comprising an interposer layer formed over the temperature compensation layer and in contact with the first electrode.

6. The acoustic resonator structure of claim 1, wherein the temperature compensation feature comprises a temperature compensation layer disposed on the second electrode.

7. The acoustic resonator structure of claim 6, further comprising an interposer layer formed over the temperature compensation layer and in contact with the second electrode.

8. The acoustic resonator structure of claim 1, wherein the temperature compensation feature comprises a temperature compensation layer embedded within the piezoelectric layer.

9. The acoustic resonator structure of claim 8, further comprising a first interposer layer formed over the temperature compensation layer, and a second interposer layer formed under the temperature compensation layer.

10. The acoustic resonator structure of claim 1, further comprising an air cavity disposed in the substrate, wherein the temperature compensation feature is disposed within a perimeter of the air cavity.

11. The acoustic resonator structure of claim 10, wherein the temperature compensation feature has an edge located at a distance of about 0-2 microns from the perimeter of the air cavity.

12. The acoustic resonator structure of claim 1, wherein the temperature coefficient of the temperature compensation feature is a positive temperature coefficient and the temperature coefficient of the piezoelectric layer, the first electrode, and the second electrode is a negative temperature coefficient.

21. The acoustic resonator structure of claim 1, wherein the planarization layer is a first planarization layer, and the acoustic resonator structure further comprises a second planarization layer disposed over the piezoelectric layer and abutting the second electrode, the planarization layer being substantially flush with the second electrode.

22. The acoustic resonator structure of claim 1, wherein ends of the temperature compensation feature are tapered.

13. An acoustic resonator structure, comprising:

a first electrode disposed on a substrate;

a piezoelectric layer disposed on the first electrode and comprising a piezoelectric material combined with at least one rare earth element;

a second electrode disposed on the piezoelectric layer;

a temperature compensation feature having a temperature coefficient offsetting at least a portion of a temperature coefficient of the piezoelectric layer, the first electrode, or the second electrode; and

a planarization layer disposed over the substrate and abutting the first electrode, the planarization layer being substantially flush with the first electrode.

14. The acoustic resonator structure of claim 13, wherein the at least one rare earth element comprises scandium (Sc).

15. The acoustic resonator structure of claim 13, wherein the at least one rare earth element comprises at least one of ytterbium (Yb), yttrium (Y), lanthanum (La), and erbium (Er).

16. The acoustic resonator structure of claim 13, wherein the piezoelectric layer comprises about 3-10 wt % of the at least one rare earth element.

17. The acoustic resonator structure of claim 13, wherein the temperature compensation feature comprises at least one of boron silicate glass (BSG), silicon dioxide (SiO₂), chromium (Cr) and tellurium oxide (TeO(x)).

18. The acoustic resonator structure of claim 13, wherein the temperature compensation feature comprises a temperature compensation layer disposed between the first electrode and the piezoelectric layer.

19. The acoustic resonator structure of claim 13, wherein the temperature compensation feature comprises a temperature compensation layer disposed on the second electrode.

20. The acoustic resonator structure of claim 13, wherein the temperature compensation feature comprises a temperature compensation layer embedded within the piezoelectric layer.

23. The acoustic resonator structure of claim 13, wherein the planarization layer is a first planarization layer, and the acoustic resonator structure further comprises a second planarization layer disposed over the piezoelectric layer and abutting the second electrode, the planarization layer being substantially flush with the second electrode.