Contour-mode piezoelectric micromechanical resonators
A contour mode micromechanical piezoelectric resonator. The resonator has a bottom electrode; a top electrode; and a piezoelectric layer disposed between the bottom electrode and the top electrode. The piezoelectric resonator has a planar surface with a cantilevered periphery, dimensioned to undergo in-plane lateral displacement at the periphery. The resonator also includes means for applying an alternating electric field across the thickness of the piezoelectric resonator. The electric field is configured to cause the resonator to have a contour mode in-plane lateral displacement that is substantially in the plane of the planar surface of the resonator, wherein the fundamental frequency for the displacement of the piezoelectric resonator is set in part lithographically by the planar dimension of the bottom electrode, the top electrode or the piezoelectric layer.
1. A micromechanical piezoelectric resonator, comprising:
a first electrode;
a second electrode;
a piezoelectric layer disposed between the first electrode and the second electrode, wherein the piezoelectric resonator comprises a planar surface and wherein the piezoelectric resonator is configured to undergo in-plane lateral displacement in response to application of an electric field to the piezoelectric layer by the first and second electrodes; and
first and second effective quarter-wavelength anchors coupling the piezoelectric resonator to a substrate at first and second sides of the piezoelectric resonator, respectively, and wherein the first and second sides are substantially opposite each other.
2. The resonator of claim 1 wherein at least one of the first electrode or the second electrode is lithographically patterned to excite a specific region or regions of the piezoelectric resonator.
3. The resonator of claim 2 wherein the first electrode and the second electrode are lithographically patterned to excite a specific region or regions of the piezoelectric resonator.
4. The resonator of claim 1 wherein said piezoelectric layer is a layer selected from the group consisting of aluminum nitride, gallium nitride, aluminum gallium arsenide, zinc oxide, quartz, zinc-sulfide, cadmium-sulfide, lithium tantalate, lithium niobate, and combinations thereof.
5. The resonator of claim 1 wherein at least one of the first electrode or second electrode is made from a material selected from the group consisting of aluminum, platinum, tungsten, molybdenum, ruthenium, chrome, gold, titanium, doped polycrystalline silicon, niobium, copper, silver, tantalum, cobalt, nickel, palladium, silicon germanium, doped conductive zinc oxide, and combinations thereof.
6. A device comprising a plurality of resonators electrically cascaded to form a network, the plurality of resonators including the resonator of claim 1 .
7. The device of claim 6 wherein said network is a Pi network, T network, L network or a lattice network.
8. The device of claim 7 , wherein the resonator forms at least part of a band pass filter circuit formed from a series of networks comprising the network.
9. The device of claim 7 , wherein at least two resonators of the plurality of resonators are electrically connected.
10. The device of claim 7 comprising electrical connectors used to route a signal from a first resonator of the plurality of resonators to a second resonator of the plurality of resonators.
11. The resonator of claim 1 , wherein the resonator is one of a plurality of resonators arranged in combination as a band-pass filter circuit.
12. The resonator of claim 1 wherein the resonator is a part of a frequency reference in an oscillator circuit.
13. The resonator of claim 1 , further comprising electrical interconnects between a patterned region or regions of the first electrode and a patterned region or regions of the second electrode.
14. The resonator of claim 1 , wherein the piezoelectric layer is configured to undergo in-plane lateral displacement in response to application of the electric field to the piezoelectric layer by the first and second electrodes.