Lateral field FBAR
AssigneeWestinghouse Electric Corp.
InventorsS. Visvanathan Krishnaswamy, Robert W. Weinert, John D. Adam, John M. Walker
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Abstract
This invention is a design for lateral field film bulk acoustic resonators (LF-FBAR). All electrodes in this design are located on one surface of the piezoelectric material, thereby simplifying manufacturing and improving performance. The gap between electrodes is limited to a specified dimension to maximize the efficiency of the device. Single and multi-pole devices are described. Barium magnesium fluoride and lithium niobate are specified as the piezoelectric material for high frequency applications.
Claims13
A lateral field film bulk acoustic resonator comprising:
- piezoelectric means operable to transform electrical energy to acoustic energy, said piezoelectric means having a thickness T.sub.p ;
- substrate means operable to support said piezoelectric means, said substrate means having a thickness T.sub.s ;
- at least two electrodes disposed on one surface of said piezoelectric means, said electrodes coupled by lateral excitation of said piezoelectric means,
- wherein said electrodes are separated by a gap no greater than 3T.sub.p.sup.2 /(T.sub.p +T.sub.s).
A lateral field film bulk acoustic resonator comprising:
- piezoelectric means operable to transform electrical energy to acoustic energy, said piezoelectric means having a thickness T.sub.p ;
- substrate means operable to support said piezoelectric means, said substrate means having a thickness T.sub.s ;
- an input electrode, an output electrode, and a ground electrode disposed on one surface of said piezoelectric means, said ground electrode being disposed between said input and output electrodes.
A lateral field film bulk acoustic resonator comprising:
- a dielectric substrate having a thickness T.sub.s disposed on a layer of semiconductor material and spanning an opening in said semiconductor material;
- a piezoelectric layer having a top surface, a bottom surface, and a thickness T.sub.p, said bottom surface disposed on said dielectric substrate opposed said opening in said semiconductor material;
- an input electrode and an output electrode disposed on said top surface of said piezoelectric layer,
- further comprising said input electrode and said output electrode being coupled by lateral field excitation of said piezoelectric layer.
A lateral field film bulk acoustic resonator comprising:
- a dielectric substrate having a thickness T.sub.s disposed on a layer of semiconductor material and spanning an opening in said semiconductor material;
- a piezoelectric layer having a top surface, a bottom surface, and a thickness T.sub.p, said bottom surface disposed on said dielectric membrane opposed said opening in said semiconductor material.
- an input electrode, an output electrode and a ground electrode disposed on said top surface of said piezoelectric layer, said ground electrode being disposed between said input and output electrodes.
Dependencies are inferred from the claim text.