US 11,929,730 B2
Acoustic wave device and forming method thereof
Ta-Cheng Hsu, Hsinchu (TW); Wei-Shou Chen, Hsinchu (TW); Chun-Yi Lin, Hsinchu (TW); Chung-Jen Chung, Hsinchu (TW); Wei-Tsuen Ye, Hsinchu (TW); and Wei-Ching Guo, Hsinchu (TW)
Assigned to EPISTAR CORPORATION, Hsinchu (TW)
Filed by EPISTAR CORPORATION, Hsinchu (TW)
Filed on Feb. 10, 2021, as Appl. No. 17/172,568.
Claims priority of application No. 109104675 (TW), filed on Feb. 14, 2020.
Prior Publication US 2021/0257986 A1, Aug. 19, 2021
Int. Cl. H03H 9/13 (2006.01); H03H 3/02 (2006.01); H03H 9/17 (2006.01); H10N 30/076 (2023.01); H10N 30/87 (2023.01)
CPC H03H 9/131 (2013.01) [H03H 3/02 (2013.01); H03H 9/173 (2013.01); H10N 30/076 (2023.02); H10N 30/877 (2023.02); H03H 2003/021 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An acoustic wave element, comprising:
a substrate;
a bonding structure on the substrate;
a support layer on the bonding structure;
a first electrode comprising a lower surface on the support layer,
a cavity positioned between the support layer and the first electrode and exposing the lower surface of the first electrode;
a piezoelectric layer on the first electrode; and
a second electrode on the piezoelectric layer;
wherein at least one of the first electrode and the second electrode comprises a first layer and a second layer that the first layer has a first acoustic impedance and a first electrical impedance, the second layer has a second acoustic impedance and a second electrical impedance, wherein the first acoustic impedance is higher than the second acoustic impedance and the second electrical impedance is lower than the first electrical impedance.