US 12,323,120 B2
Bulk acoustic wave resonator and fabrication method for the bulk acoustic wave resonator
Ping Lv, Suzhou (CN); Gang Li, Suzhou (CN); and Wei Hu, Suzhou (CN)
Assigned to MEMSensing Microsystems (Suzhou, China) Co., Ltd., Suzhou (CN)
Filed by MEMSensing Microsystems (Suzhou, China) Co., Ltd., Suzhou (CN)
Filed on Jun. 18, 2021, as Appl. No. 17/351,594.
Application 17/351,594 is a continuation of application No. PCT/CN2019/119746, filed on Nov. 20, 2019.
Claims priority of application No. 201811564949.9 (CN), filed on Dec. 20, 2018.
Prior Publication US 2021/0313946 A1, Oct. 7, 2021
Int. Cl. H03H 9/17 (2006.01); H03H 3/02 (2006.01); H03H 9/13 (2006.01)
CPC H03H 3/02 (2013.01) [H03H 9/13 (2013.01); H03H 9/17 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A bulk acoustic wave resonator, comprising:
a device structure comprising a silicon substrate, the silicon substrate comprising an indentation partially penetrating the silicon substrate;
a third silicon dioxide layer bonded on the device structure, the third silicon dioxide layer covering the indentation to form a cavity inside the silicon substrate, and a material of the third silicon dioxide layer being silicon dioxide;
a resonant piezoelectric stack on the third silicon dioxide layer, the resonant piezoelectric stack comprising a piezoelectric film, and a first electrode and a second electrode that are in contact with the piezoelectric film and are independent of each other; and
a lead out pad, comprising a first pad and a second pad connected to the first electrode and the second electrode respectively,
wherein there is a bonding interface between the device structure and the third silicon dioxide layer, and the bonding interface comprises a SiO2—SiO2 interface or a Si—SiO2 interface.