US 12,308,820 B2
Acoustic wave device
Sho Nagatomo, Nagaokakyo (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Jul. 13, 2022, as Appl. No. 17/863,447.
Application 17/863,447 is a continuation of application No. PCT/JP2020/049242, filed on Dec. 28, 2020.
Claims priority of application No. 2020-006608 (JP), filed on Jan. 20, 2020.
Prior Publication US 2022/0345105 A1, Oct. 27, 2022
Int. Cl. H03H 9/02 (2006.01)
CPC H03H 9/02992 (2013.01) [H03H 9/02574 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An acoustic wave device comprising:
a semiconductor support including a principal surface;
a piezoelectric layer directly or indirectly on the principal surface of the semiconductor support; and
an IDT electrode on one principal surface of the piezoelectric layer; wherein
the IDT electrode includes:
a first busbar and a second busbar opposed to each other;
first electrode fingers each including a respective one end connected to the first busbar; and
second electrode fingers each including a respective one end connected to the second busbar, the second electrode fingers being interdigitated with the first electrode fingers;
the IDT electrode includes gaps between the first busbar and the second electrode fingers and between the second busbar and the first electrode fingers;
a cavity is provided in at least a portion of the semiconductor support, the portion overlapping the gaps as viewed in plan;
no cavity is provided in at least a portion of the semiconductor support, the portion overlapping the IDT electrode as viewed in plan;
the cavity opens toward the piezoelectric layer; and
a portion of the IDT electrode that overlaps the cavity as viewed in plan is smaller than a portion of the IDT electrode that overlaps the at least a portion of the semiconductor support in which no cavity is provided as viewed in plan.