Integration of piezoelectric materials with substrates
Devices having piezoelectric material structures integrated with substrates are described. Fabrication techniques for forming such devices are also described. The fabrication may include bonding a piezoelectric material wafer to a substrate of a differing material. A structure, such as a resonator, may then be formed from the piezoelectric material wafer.
1. A packaged micromechanical resonator, comprising:
a substrate;
a cap comprising integrated circuitry;
a first portion of an electrically conductive material between the substrate and the cap, disposed such that the substrate, the cap, and the first portion of the electrically conductive material define a sealed, enclosed volume;
a micromechanical resonator comprising a piezoelectric material disposed within the enclosed volume; and
a second portion of the electrically conductive material between the substrate and the cap constructed and arranged such that a signal can be transmitted between the micromechanical resonator and the integrated circuitry through the second portion of the electrically conductive material.
2. A packaged micromechanical resonator, comprising:
a substrate;
a cap comprising integrated circuitry;
a first portion of an electrically conductive material between the substrate and the cap, disposed such that the substrate, the cap, and the first portion of the electrically conductive material define a sealed, enclosed volume;
a micromechanical resonator disposed within the enclosed volume; and
a second portion of the electrically conductive material between the substrate and the cap constructed and arranged such that a signal can be transmitted between the micromechanical resonator and the integrated circuitry through the second portion of the electrically conductive material;
wherein the first and/or second portions of the electrically conductive material have an average thickness of at least about 5 microns.
3. A packaged micromechanical resonator, comprising:
a substrate;
a cap comprising integrated circuitry;
a first portion of an electrically conductive material between the substrate and the cap, disposed such that the substrate, the cap, and the first portion of the electrically conductive material define a sealed, enclosed volume;
a micromechanical resonator configured to oscillate in plane disposed within the enclosed volume; and
a second portion of the electrically conductive material between the substrate and the cap constructed and arranged such that a signal can be transmitted between the micromechanical resonator and the integrated circuitry through the second portion of the electrically conductive material.
4. A method of packaging a micromechanical resonator, comprising:
providing a substrate on which a micromechanical resonator is disposed;
providing a cap comprising integrated circuitry;
positioning first and second portions of an electrically conductive material between the substrate and the cap; and
modifying the first and second portions of the electrically conductive material such that the first portion of the electrically conductive material produces a seal between the substrate and the cap and such that a signal can be transmitted between the micromechanical resonator and the integrated circuitry through the second portion of the electrically conductive material.
5. A resonator as in claim 1 , wherein the resonator comprises a microelectromechanical systems (MEMS) resonator.
6. A resonator as in claim 1 , wherein the resonator is configured to support Lamb waves.
7. A resonator as in claim 1 , wherein the resonator comprises a piezoelectric material.
8. A resonator as in claim 1 , wherein the resonator comprises a piezoelectric material chosen from the group consisting of: aluminum nitride (AlN), zinc oxide (ZnO), cadmium sulfide (CdS), lead titanate (PbTiO 3 ), lead zirconate titanate (PZT), lithium niobate (LiNbO 3 ), lithium tantalate (LiTaO 3 ), potassium niobate (KNbO 3 ), Li 2 B 4 O 7 , langasite (La 3 Ga 5 SiO 14 ), gallium arsenside (GaAs), barium sodium niobate, bismuth germanium oxide, indium arsenide, and indium antimonide.
9. A resonator as in claim 1 , wherein the resonator is suspended above the substrate.
10. A resonator as in claim 1 , wherein the substrate has a cavity formed therein, and wherein the resonator is suspended above the cavity.
11. A resonator as in claim 1 , wherein the first and/or second portions of electrically conductive material comprise an electrically conductive polymer and/or a metal.
12. A resonator as in claim 1 , wherein the first and/or second portions of electrically conductive material comprise gold, silver, copper, and/or tin.
13. A resonator as in claim 1 , wherein the integrated circuitry is constructed and arranged to control the resonator.
14. A resonator as in claim 1 , wherein the integrated circuitry is constructed and arranged to actuate the resonator and/or detect vibration of the resonator.
15. A resonator as in claim 1 , wherein the first portion of the electrically conductive material circumscribes the resonator.
16. A resonator as in claim 1 , wherein the first and/or second portions of the electrically conductive material have a resistivity of less than about 1000 Ωm.
17. A resonator as in claim 1 , wherein the packaged resonator comprises a hermetic seal.
18. A method as in claim 4 , wherein modifying the first and/or second portions of the electrically conductive material comprises heating the first and/or second portions of the electrically conductive material.
19. A resonator as in claim 1 , wherein the first and/or second portions of the electrically conductive material has a thermal conductivity of at least about 5 W/mK.
20. A resonator as in claim 1 , wherein the second portion of the electrically conductive material is used as part of a ground electrical connection.
21. A resonator as in claim 1 , wherein the first and/or second portions of the electrically conductive material are printed, sputtered, or evaporated onto the substrate and/or cap.
22. A resonator as in claim 1 , wherein the substrate and/or cap comprises at least a portion of a semiconductor wafer.
23. A resonator as in claim 1 , wherein the first and/or second portions of the electrically conductive material have an average thickness of between about 0.1 microns and about 100 microns.
24. A resonator as in claim 1 , wherein the first and second portions of the electrically conductive material are the same portion of the electrically conductive material.
25. A resonator as in claim 1 , wherein the first and second portions of the electrically conductive material are different portions of the electrically conductive material.
26. A resonator as in claim 1 , wherein the first and second portions of the electrically conductive material have the same chemical composition.
27. A resonator as in claim 1 , wherein the first and second portions of the electrically conductive material have different chemical compositions.
28. The resonator of claim 1 , wherein the first portion of the electrically conductive material forms a seal between the substrate and the cap.
29. The resonator of claim 28 , wherein the seal is a hermetic seal.
30. The resonator of claim 29 , wherein the seal makes a vacuum seal.
31. The resonator of claim 29 , wherein the seal makes a no-vacuum seal.
32. The resonator of claim 28 , wherein the seal is a non-hermetic seal.