Transversely-excited film bulk acoustic resonator comprising small cells
Acoustic resonator devices are disclosed. An acoustic resonator device includes a plurality of cells electrically connected in parallel. Each cell includes an interdigital transducer (IDT) on a piezoelectric plate, the IDT having at least 15 and not more than 35 interleaved fingers.
1. An acoustic resonator device comprising:
a plurality of cells electrically connected in parallel, each cell comprising:
an interdigital transducer (IDT) on a portion of a piezoelectric plate, the IDT having at least 15 and not more than 35 interleaved fingers, wherein the interleaved fingers of the IDTs of two or more of the plurality of cells are on a common diaphragm; and
a heat sink finger between adjacent cells on the common diaphragm.
2. The device of claim 1 , wherein the piezoelectric plate and the IDT of each of the plurality of cells are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode in the piezoelectric plate.
3. The device of claim 1 , each cell further comprising:
one or more reflector elements proximate and parallel to each terminal finger of the IDT.
4. The device of claim 1 , each cell further comprising:
two reflector elements proximate and parallel to each terminal finger of the IDT.
5. The device of claim 1 , wherein the common diaphragm spans respective cavities in a substrate.
6. The device of claim 1 , wherein reflector elements between adjacent cells on the common diaphragm are shared by the adjacent cells.
7. The device of claim 5 , further comprising:
one or more openings through the common diaphragm between adjacent cells on the common diaphragm.
8. The device of claim 1 , further comprising:
an acoustic Bragg reflector between a back surface of the piezoelectric plate and a substrate,
wherein the IDTs of the plurality of cells are on a front surface of the piezoelectric plate.
9. An acoustic resonator device comprising:
a plurality of cells electrically connected in parallel, each cell comprising:
a portion of a piezoelectric plate; and
an interdigital transducer (IDT) on the portion of the piezoelectric plate, the IDT comprising interleaved fingers,
wherein the portion of the piezoelectric plate and the IDT of each of the plurality of cells are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode in the portion of the piezoelectric plate, and
wherein each of the plurality of cells are acoustically isolated from the other cells.
10. The device of claim 9 , wherein each of the plurality of cells comprises a same number of interleaved fingers.
11. The device of claim 9 , each cell further comprising:
one or more reflector elements proximate and parallel to each terminal finger of the IDT.
12. The device of claim 10 , wherein reflector elements between adjacent cells are shared by the adjacent cells.
13. The device of claim 9 , further comprising a heat sink finger between adjacent cells.
14. The device of claim 9 , wherein the portion of the piezoelectric plate is a diaphragm.
15. The device of claim 9 , wherein the portions of the piezoelectric plate of each of the plurality of cells are portions of the same piezoelectric plate, and the acoustic resonator device further comprises one or more openings through the piezoelectric plate between adjacent cells.
16. The device of claim 9 , further comprising:
an acoustic Bragg reflector between a back surface of the piezoelectric plate and a substrate,
wherein the IDTs of the plurality of cells are on a front surface of the piezoelectric plate.
17. An acoustic resonator device comprising:
a plurality of cells electrically connected in parallel, each cell comprising:
an interdigital transducer (IDT) on a portion of a piezoelectric plate, the IDT having at least 15 and not more than 35 interleaved fingers, wherein the interleaved fingers of the IDTs of two or more of the plurality of cells are on a common diaphragm; and
one or more openings through the common diaphragm between adjacent cells on the common diaphragm.
18. The device of claim 17 wherein the piezoelectric plate and the IDT of each of the plurality of cells are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode in the piezoelectric plate.
19. The device of claim 17 , each cell further comprising:
one or more reflector elements proximate and parallel to each terminal finger of the IDT.
20. The device of claim 17 , each cell further comprising:
two reflector elements proximate and parallel to each terminal finger of the IDT.
21. The device of claim 17 wherein reflector elements between adjacent cells on the common diaphragm are shared by the adjacent cells.
22. The device of claim 17 further comprising:
an acoustic Bragg reflector between a back surface of the piezoelectric plate and a substrate,
wherein the IDTs of the plurality of cells are on a front surface of the piezoelectric plate.