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 device comprising:
a first wafer comprising a substrate comprising a first material;
a second wafer comprising a mechanical resonator comprising a piezoelectric material, different from the first material;
a cap bonded to the substrate to form a hermetically sealed environment for the mechanical resonator; and
integrated circuitry formed on the substrate and coupled to the mechanical resonator to control the mechanical resonator,
wherein the first wafer is integrated with the second wafer such that the mechanical resonator is integrated with the substrate, and
wherein the integrated circuitry is coupled to the mechanical resonator by at least one thru-silicon via (TSV).
2. The device of claim 1 , wherein the piezoelectric material is a single crystal piezoelectric material.
3. The device of claim 2 , wherein the single crystal piezoelectric material is quartz.
4. The device of claim 3 , wherein the first material is silicon.
5. The device of claim 1 , wherein the mechanical resonator is suspended above the substrate.
6. The device of claim 5 , wherein the substrate has a cavity formed therein, and wherein the mechanical resonator is suspended above the cavity.
7. The device of claim 1 , wherein the piezoelectric material is 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.
8. The device of claim 1 , wherein the integrated circuitry actuates the mechanical resonator and/or detects vibration of the mechanical resonator.
9. The device of claim 1 , wherein the device further comprises integrated circuitry formed on the cap and coupled to the mechanical resonator.
10. The device of claim 9 , wherein the integrated circuitry formed on the substrate actuates the mechanical resonator and/or detects vibration of the mechanical resonator.
11. The device of claim 1 , further comprising a stack of a plurality of layers of alternating low and high acoustic impedance integrated with the substrate.
12. The device of claim 11 , wherein the mechanical resonator is a solidly mounted mechanical resonator integrated with the stack.
13. The device of claim 1 , wherein the mechanical resonator has an operating frequency ranging from 30 to 35 kHz.
14. The device of claim 1 , wherein the mechanical resonator has an operating frequency ranging from 60 to 70 kHz.
15. The device of claim 1 , wherein the mechanical resonator has an operating frequency ranging from 10 Mhz to 1 GHz.
16. The device of claim 1 , wherein the mechanical resonator has an operating frequency ranging from 1 GHz to 3 GHz.
17. The device of claim 1 , wherein the mechanical resonator has an operating frequency ranging from 3 GHz to 10 GHz.
18. The device of claim 4 , wherein the first material is single crystal silicon.
19. The device of claim 1 , wherein the mechanical resonator has a resonance frequency between approximately 50 MHz and 1 GHz.
20. The device of claim 1 , wherein the mechanical resonator has a resonance frequency between approximately 30 kHz and 35 kHz.
21. The device of claim 1 , wherein the mechanical resonator has a resonance frequency between approximately 3 GHz and 10 GHz.
22. The device of claim 1 , wherein the integrated circuitry detects vibration of the mechanical resonator.
23. The device of claim 2 , wherein the first wafer is a silicon wafer and wherein the single crystal piezoelectric material comprises quartz.
24. The device of claim 2 , wherein the first wafer is a silicon wafer and wherein the single crystal piezoelectric material comprises LiTaO 3 .
25. The device of claim 1 ,
wherein the mechanical resonator is a plate acoustic wave resonator.
26. The device of claim 25 , wherein the piezoelectric material is single crystal quartz.
27. The device of claim 25 , wherein the integrated circuitry both controls operation of the mechanical resonator and detects vibration of the mechanical resonator.
28. The device of claim 25 , wherein the substrate has a cavity formed therein, and wherein the mechanical resonator is suspended above the cavity.
29. The device of claim 25 , wherein the mechanical resonator is a quartz resonator.
30. The device of claim 1 , wherein the cap is bonded to the substrate by a metallization layer.