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US 12,647,099 B2Granted
Transversely-excited film bulk acoustic resonator with optimized piezoelectric plate thickness
AssigneeMurata Manufacturing Co., Ltd.
InventorsGreg Dyer, Bryant Garcia, Julius Koskela, Robert B. Hammond, Patrick Turner, Viktor Plesski, Ventsislav Yantchev, Soumya Yandrapalli
Life of this patent
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Abstract
Acoustic resonators and filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate forming a diaphragm, and a conductor pattern on the front surface, the conductor pattern including a multi-mark interdigital transducer (IDT), fingers of the IDT on the diaphragm. A thickness between the front and back surfaces is greater than or equal to 200 nm and less than or equal to 1000 nm.
Claims15
An acoustic resonator, comprising:
- a piezoelectric plate having front and back surfaces, a portion of the piezoelectric plate including a diaphragm;
- and
- a conductor pattern on the front surface, the conductor pattern comprising a multi-mark interdigital transducer (IDT) having a plurality of fingers disposed on the diaphragm,
- wherein a thickness between the front and back surfaces of the piezoelectric plate is greater than or equal to 200 nm and less than or equal to 1000 nm,
- wherein the plurality of fingers include a first edge finger, a second edge finger and at least one finger between the first edge finger and the second edge finger, and
- wherein a mark of the first edge finger is m(1−δm), and a mark of the second edge finger is m(1+δm) when a mark of the at least one finger is m, and om is greater than 0 and less than 1,
- wherein:
- the plurality of fingers include a first set of fingers extended from a first busbar and a second set of fingers extended from a second busbar,
- the first and second sets of fingers are interleaved fingers that include the first edge finger, the second edge finger and the at least one finger,
- at least a first hole is disposed between an end of a finger of the first set of fingers and the second busbar, the first hole being closer to the end of the finger of the first set of fingers than the second busbar, and
- at least a second hole is disposed between an end of a finger of the second set of fingers and the first busbar.
8 more elements
A filter device, comprising:
- a piezoelectric layer having front and back surfaces, portions of the piezoelectric layer comprising one or more diaphragms;
- and
- a conductor pattern on the front surface of the piezoelectric layer, the conductor pattern comprising a plurality of multi-mark interdigital transducers (IDTs),
- wherein interleaved fingers of the plurality of IDTs are disposed on the one or more diaphragms, respectively,
- wherein a thickness between the front and back surfaces of the piezoelectric layer is greater than or equal to 200 nm and less than or equal to 1000 nm
- wherein the interleaved fingers of at least one IDT of the plurality of IDTs include a first edge finger, a second edge finger and at least one finger between the first edge finger and the second edge finger, and
- wherein a mark of the first edge finger is m(1−δm), and a mark of the second edge finger is m(1+δm) when a mark of the at least one finger is m, and om is greater than 0 and less than 1,
- wherein, for the at least one IDT:
- the interleaved fingers include a first set of fingers extended from a first busbar and a second set of fingers extended from a second busbar,
- at least a first hole is disposed between an end of a finger of the first set of fingers and the second busbar, the first hole being closer to the end of the finger of the first set of fingers than the second busbar, and
- at least a second hole is disposed between an end of a finger of the second set of fingers and the first busbar.
8 more elements
Dependencies are inferred from the claim text.