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
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.
Claims28
An acoustic resonator device comprising:
- a piezoelectric plate;
- and
- an interdigital transducer (IDT) at a surface of the piezoelectric plate, the IDT comprising interleaved fingers,
- wherein at least one interleaved finger of the interleaved fingers comprises 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.
A filter device comprising:
- at least one piezoelectric plate;
- and
- a conductor pattern at a surface of the at least one piezoelectric plate, the conductor pattern including a plurality of interdigital transducers (IDTs) of a respective plurality of acoustic resonators, each of the plurality of IDTs comprising interleaved fingers,
- wherein at least one interleaved finger of the interleaved fingers of at least one of the plurality of IDTs comprises a first layer adjacent the at least one 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.
A method of fabricating an acoustic resonator device, comprising:
- forming an interdigital transducer (IDT) on a surface of a piezoelectric plate such that interleaved fingers of the IDT are disposed at the piezoelectric plate,
- wherein at least one interleaved finger comprises 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.
Dependencies are inferred from the claim text.