Decoupled transversely-excited film bulk acoustic resonators
AssigneeMurata Manufacturing Co., Ltd.
InventorSean McHugh
Life of this patent
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Abstract
Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate supported by the substrate. A portion of the piezoelectric plate suspended across a cavity in the substrate forms a diaphragm. A decoupling dielectric layer is on a front surface of the diaphragm. An interdigital transducer (IDT) has interleaved fingers on the decoupling dielectric layer over the diaphragm. The IDT and piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites shear acoustic waves in the diaphragm.
Claims20
A bulk acoustic resonator comprising:
- a substrate;
- a piezoelectric layer attached directly or by one or more intermediate layers to the substrate, the piezoelectric layer including a diaphragm over a cavity of the bulk acoustic resonator;
- a decoupling dielectric layer on a surface of the diaphragm and that extends continuously on the surface of the diaphragm, such that an entirety of the surface of the diaphragm is covered by the decoupling layer;
- and
- an interdigital transducer (IDT) with interleaved fingers on the decoupling layer such that the decoupling layer is between the IDT and the diaphragm of the piezoelectric layer.
A bulk acoustic resonator comprising:
- a substrate;
- a piezoelectric layer attached by one or more intermediate layers to the substrate, the piezoelectric layer including a diaphragm over a cavity of the acoustic resonator;
- a decoupling dielectric layer on a surface of the diaphragm;
- and
- an interdigital transducer (IDT) with interleaved fingers on the decoupling layer opposite the diaphragm,
- wherein a thickness of the piezoelectric layer is greater than or equal to 200 nm and less than or equal to 1000 nm, and
- wherein a thickness of the decoupling dielectric layer is greater than or equal to 0.05 times the thickness of the piezoelectric layer and less than or equal to 0.5 times the thickness of the piezoelectric layer.
A bulk acoustic resonator comprising:
- a substrate;
- a piezoelectric layer attached directly or by one or more intermediate layers to the substrate;
- a decoupling dielectric layer on the piezoelectric layer, the decoupling dielectric layer extending continuously on a surface of the piezoelectric layer;
- and
- an interdigital transducer (IDT) comprising a plurality of interleaved fingers extending alternately from first and second busbars, overlapping portions of the plurality of interleaved fingers disposed directly on the decoupling layer, such that the decoupling layer is between the interleaved fingers and the surface of the piezoelectric layer,
- wherein the decoupling layer extends continuously between the interleaved fingers of the IDT and the piezoelectric layer.
Dependencies are inferred from the claim text.