Capacitively and piezoelectrically transduced micromechanical resonators
In one embodiment, a hybrid micromechanical resonator includes a capacitive resonator element and a piezoelectric resonator element, wherein the resonator can be capacitively and piezoelectrically transduced.
1. A hybrid micromechanical resonator comprising:
a capacitive resonator element; and
a piezoelectric resonator element formed on top of the capacitive resonator element;
wherein the resonator can be capacitively and piezoelectrically transduced.
2. The hybrid micromechanical resonator of claim 1 , wherein the capacitive resonator element comprises a capacitive resonator body and capacitive electrodes, wherein the capacitive resonator body is isolated from the capacitive electrodes by capacitive gaps.
3. The hybrid micromechanical resonator of claim 2 , wherein the capacitive gaps comprise dielectric material.
4. The hybrid micromechanical resonator of claim 2 , wherein the capacitive gaps are air gaps.
5. The hybrid micromechanical resonator of claim 2 , wherein the resonator is fabricated on a silicon-on-insulator (SOI) wafer comprising a handle layer, a buried oxide layer, and a device layer, wherein the resonator body comprises a portion of the device layer.
6. The hybrid micromechanical resonator of claim 5 , wherein a portion of the buried oxide layer adjacent the resonator body is removed to form a cavity that enables the capacitive resonator body to resonate.
7. The hybrid micromechanical resonator of claim 1 , wherein the piezoelectric resonator element comprises a bottom electrode, a top electrode, and a layer of piezoelectric material sandwiched between the electrodes.
8. A hybrid micromechanical resonator comprising:
a capacitive resonator element including a capacitive resonator body and capacitive electrodes, wherein the capacitive resonator body is isolated form the capacitive electrodes by capacitive gaps; and
a piezoelectric resonator element formed on top of the capacitive resonator body of the capacitive resonator element, the piezoelectric resonator element including a bottom electrode, a top electrode, and a layer of piezoelectric material sandwiched between the electrodes;
wherein the resonator can be capacitively and piezoelectrically transduced.
9. The hybrid micromechanical resonator of claim 8 , wherein the capacitive resonator body and the piezoelectric resonator element together form a hybrid resonator body.
10. The hybrid micromechanical resonator of claim 8 , wherein the capacitive resonator body resonates in contour mode.
11. The hybrid micromechanical resonator of claim 10 , wherein the capacitive resonator body is circular.
12. The hybrid micromechanical resonator of claim 8 , wherein the piezoelectric resonator element resonates in contour mode.
13. The hybrid micromechanical resonator of claim 12 , wherein the piezoelectric resonator element is circular.
14. The hybrid micromechanical resonator of claim 8 , wherein the resonator is fabricated on a silicon-on-insulator (SOI) wafer comprising a handle layer, a buried oxide layer, and a device layer, wherein the resonator body comprises a portion of the device layer.
15. The hybrid micromechanical resonator of claim 14 , wherein a portion of the buried oxide layer adjacent the resonator body is removed to form a cavity that enables the capacitive resonator body to resonate.
16. A method for fabricating a hybrid micromechanical resonator, the method comprising:
forming a capacitive resonator element; and
forming a piezoelectric resonator element on top of the capacitive resonator.
17. The method of claim 16 , wherein forming a capacitive resonator element comprises forming a capacitive resonator body and capacitive electrodes, wherein the capacitive resonator body is isolated form the capacitive electrodes by capacitive gaps.
18. The method of claim 17 , wherein forming a piezoelectric resonator element comprises forming on the capacitive resonator body a bottom electrode, a top electrode, and a layer of piezoelectric material sandwiched between the top and bottom electrodes.
19. The method of claim 18 , wherein forming a capacitive resonator element comprises forming the capacitive resonator element from a silicon-on-insulator (SOI) wafer comprising a handle layer, a buried oxide layer, and a device layer, wherein the resonator body comprises a portion of the device layer.