Acoustic resonator comprising aluminum scandium nitride and temperature compensation feature
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.
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.
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 (SiO 2 ), 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.
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.
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.