Transversely-excited film bulk acoustic resonators with electrodes having a second layer of variable width
AssigneeMurata Manufacturing Co., Ltd.
InventorsViktor PLESSKI, Julius KOSKELA
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Abstract
An acoustic resonator device is provided that includes a piezoelectric layer; and an interdigital transducer (IDT) at a surface of the piezoelectric layer, the IDT comprising interleaved fingers. At least one interleaved finger of the interleaved fingers comprises a first layer and a second layer over the first layer, wherein the first layer is between the piezoelectric layer and the second layer. Moreover, a shape of the second layer varies with respect to at least one other interleaved finger of the interleaved fingers. A thickness of the first layer is less than a thickness of the second layer.
Claims20
An acoustic resonator device comprising:
- a piezoelectric layer;
- and
- an interdigital transducer (IDT) at a surface of the piezoelectric layer, the IDT comprising interleaved fingers,
- wherein at least one interleaved finger of the interleaved fingers comprises a first layer and a second layer over the first layer, wherein the first layer is between the piezoelectric layer and the second layer,
- wherein a shape of the second layer varies with respect to at least one other interleaved finger of the interleaved fingers, and
- wherein a thickness of the first layer is less than a thickness of the second layer.
A filter device comprising:
- a plurality of bulk acoustic resonators, each comprising:
- a piezoelectric layer;
- and
- a conductor pattern at a surface of the piezoelectric layer, the conductor pattern including an interdigital transducer (IDT) having interleaved fingers,
- wherein at least one interleaved finger of the interleaved fingers comprises a first layer either adjacent the piezoelectric layer, or separated from the piezoelectric layer by an intermediate layer, and a second layer over the first layer,
- wherein, for at least one of the plurality of bulk acoustic resonators, a shape of the second layer of a first interleaved finger of the interleaved fingers is different from a shape of the second layer of a second interleaved finger of the interleaved fingers, and
- wherein, for at least one of the plurality of acoustic resonators, a thickness of the first layer of the at least one interleaved finger of the interleaved fingers is less than a thickness of the second layer of the at least one interleaved finger of the interleaved fingers.
An acoustic resonator device comprising:
- a piezoelectric layer;
- and
- an interdigital transducer (IDT) at a surface of the piezoelectric layer, the IDT comprising a pair of busbars with interleaved fingers extending therefrom, respectively,
- wherein at least one interleaved finger of the interleaved fingers comprises a first layer on the piezoelectric layer and a second layer over the first layer,
- wherein a width of the second layer of the at least one interleaved finger varies as the at least one interleaved finger extends from the respective busbar of the pair of busbars,
- wherein a thickness of the first layer is less than a thickness of the second layer, and
- wherein a pitch is a distance between two adjacent fingers extending from different busbars of the conductor pattern, wherein the pitch is between 2 and 20 times the thickness of the piezoelectric layer.
Dependencies are inferred from the claim text.