Transversely-excited film bulk acoustic resonators with electrodes having a second layer of variable width
AssigneeMurata Manufacturing Co., Ltd.
InventorsViktor Plesski, Julius Koskela
Life of this patent
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Abstract
There is disclosed acoustic resonators and filter devices. An acoustic resonator device includes a piezoelectric plate, and an interdigital transducer (IDT) formed on a front surface of the piezoelectric plate. The IDT includes interleaved fingers. At least one of the interleaved fingers includes a first layer adjacent the piezoelectric plate and a second layer over the first layer, wherein a width of the first layer is constant, and wherein a width of the second layer varies along a length of the at least one interleaved finger.
Claims18
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 adjacent the piezoelectric layer and a second layer over the first layer,
- wherein a width of the second layer varies along a length of the at least one interleaved finger, and
- wherein a thickness of the first layer is less than a thickness of the second layer.
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 at the piezoelectric layer and a second layer over the first layer and opposite the piezoelectric layer,
- wherein a width of the second layer of the at least one interleaved finger varies as the at least one interleaved finger extends away from the respective busbar of the pair of busbars, and
- wherein a thickness of the first layer is less than a thickness of the second layer.
A filter device comprising:
- a plurality of 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 adjacent the piezoelectric layer and a second layer over the first layer,
- wherein a width of the second layer varies along a length of the at least one interleaved finger, and
- wherein, for at least one of the plurality of acoustic resonators, a thickness of the first layer of the at least one of the interleaved fingers is less than a thickness of the second layer.
Dependencies are inferred from the claim text.