US 12,463,615 B2
Transversely-excited film bulk acoustic resonators with improved coupling and reduced energy leakage
Sean McHugh, Santa Barbara, CA (US); and Filip Iliev, San Francisco, CA (US)
Assigned to MURATA MANUFACTURING CO., LTD, Nagaokakyo (JP)
Filed by MURATA MANUFACTURING CO., LTD, Kyoto (JP)
Filed on Nov. 22, 2021, as Appl. No. 17/533,081.
Claims priority of provisional application 63/140,030, filed on Jan. 21, 2021.
Prior Publication US 2022/0231657 A1, Jul. 21, 2022
Int. Cl. H03H 9/02 (2006.01); H03H 3/02 (2006.01); H03H 9/205 (2006.01); H03H 9/56 (2006.01)
CPC H03H 9/02228 (2013.01) [H03H 3/02 (2013.01); H03H 9/02015 (2013.01); H03H 9/02157 (2013.01); H03H 9/205 (2013.01); H03H 9/568 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An acoustic resonator device comprising:
a piezoelectric layer;
an interdigital transducer (IDT) on a surface of the piezoelectric layer and comprising a plurality of first fingers extending from a first busbar and a plurality of second fingers extending from a second busbar, such that the first and second plurality of fingers are interleaved fingers that have an overlapping distance that defines an aperture of the IDT; and
at least one dielectric layer over and between the interleaved fingers of the IDT,
wherein the aperture has a first edge that is defined by a line passing along ends of the first plurality of fingers and that opposes the second busbar,
wherein the aperture has a second edge that is defined by a line passing along ends of the second plurality of fingers and that opposes the first busbar,
wherein the at least one dielectric layer continuously extends beyond the first edge of the aperture but not to the second busbar and also continuously extends beyond the second edge of the aperture but not to the first busbar, and
wherein the least one dielectric layer is thinner in at least a region between the first edge of the aperture and the second busbar than a region over the aperture of the IDT.