US 11,996,823 B2
Air-gap type film bulk acoustic resonator
Byung Hun Kim, Gyeonggi-do (KR); and Jong Hyeon Park, Gyeonggi-do (KR)
Assigned to WISOL CO., LTD., Gyeonggi-do (KR)
Filed by WISOL CO., LTD., Gyeonggi-do (KR)
Filed on Feb. 24, 2021, as Appl. No. 17/183,487.
Claims priority of application No. 10-2020-0140116 (KR), filed on Oct. 27, 2020.
Prior Publication US 2022/0131524 A1, Apr. 28, 2022
Int. Cl. H03H 9/17 (2006.01); H03H 9/13 (2006.01)
CPC H03H 9/171 (2013.01) [H03H 9/13 (2013.01)] 7 Claims
OG exemplary drawing
 
2. An air-gap type film bulk acoustic resonator (FBAR) comprising:
a substrate comprising an air-gap portion on a top surface;
a lower electrode having a polygonal plate shape above the substrate and configured to surround a top of the air-gap portion;
a piezoelectric layer formed above the lower electrode; and
an upper electrode formed above the piezoelectric layer,
wherein the lower electrode comprises an electrode non-deposited area formed between one side plate boundary surface of the polygonal plate and one side air-gap boundary surface of the air-gap portion to expose one part of a top of the air-gap portion,
wherein a part of the one side air-gap boundary surface protrudes with a certain width in a direction opposite to a center of the air-gap portion to form the electrode non-deposited area between the one side plate boundary surface and the one side air-gap boundary surface.