US 12,255,607 B2
Transversely-excited film bulk acoustic resonator with buried oxide strip acoustic confinement structures
Andrew Kay, Provo, UT (US); Sean McHugh, Santa Barbara, CA (US); John Koulakis, Los Angeles, CA (US); and Albert Cardona, Santa Barbara, CA (US)
Assigned to Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Dec. 17, 2021, as Appl. No. 17/555,353.
Application 17/555,353 is a continuation in part of application No. 17/542,290, filed on Dec. 3, 2021.
Claims priority of provisional application 63/237,050, filed on Aug. 25, 2021.
Claims priority of provisional application 63/208,503, filed on Jun. 9, 2021.
Claims priority of provisional application 63/191,897, filed on May 21, 2021.
Claims priority of provisional application 63/187,932, filed on May 12, 2021.
Claims priority of provisional application 63/182,465, filed on Apr. 30, 2021.
Prior Publication US 2022/0352868 A1, Nov. 3, 2022
Int. Cl. H03H 9/02 (2006.01); H03H 3/02 (2006.01); H03H 9/13 (2006.01); H03H 9/17 (2006.01); H03H 9/56 (2006.01)
CPC H03H 9/02228 (2013.01) [H03H 3/02 (2013.01); H03H 9/02031 (2013.01); H03H 9/132 (2013.01); H03H 9/174 (2013.01); H03H 9/176 (2013.01); H03H 9/562 (2013.01); H03H 9/564 (2013.01); H03H 2003/023 (2013.01)] 19 Claims
OG exemplary drawing
 
1. An acoustic resonator comprising:
a substrate;
a piezoelectric layer supported by the substrate and including a portion that forms a diaphragm that is over a cavity of the acoustic resonator;
an interdigital transducer (IDT) on the piezoelectric plate, the IDT comprising interleaved interdigital transducer (IDT) fingers extending from first and second busbars respectively, wherein:
the interleaved IDT fingers extend onto the diaphragm, and
overlapping portions of the interleaved IDT fingers define an aperture of the acoustic resonator;
a first dielectric strip on the piezoelectric layer, a first portion of the first dielectric strip under the interleaved IDT fingers in a first margin of the aperture and a second portion of the first dielectric strip extending into a first gap between the first margin and the first busbar; and
a second dielectric strip on the piezoelectric layer, a first portion of the second dielectric strip under the interleaved IDT fingers in a second margin of the aperture and a second portion of the second dielectric strip extending into a second gap between the second margin and the second busbar.