US 11,750,171 B2
Layered body, and saw device
Keiichirou Geshi, Osaka (JP); Masato Hasegawa, Osaka (JP); and Shigeru Nakayama, Osaka (JP)
Assigned to SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Appl. No. 16/754,811
Filed by SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
PCT Filed Sep. 21, 2018, PCT No. PCT/JP2018/034960
§ 371(c)(1), (2) Date Apr. 9, 2020,
PCT Pub. No. WO2019/073781, PCT Pub. Date Apr. 18, 2019.
Claims priority of application No. 2017-198778 (JP), filed on Oct. 12, 2017.
Prior Publication US 2021/0104999 A1, Apr. 8, 2021
Int. Cl. H03H 9/02 (2006.01); H03H 3/08 (2006.01); H03H 9/25 (2006.01); H10N 30/06 (2023.01); H10N 30/072 (2023.01); H10N 30/086 (2023.01)
CPC H03H 9/02574 (2013.01) [H03H 3/08 (2013.01); H03H 9/02559 (2013.01); H03H 9/02897 (2013.01); H03H 9/25 (2013.01); H10N 30/06 (2023.02); H10N 30/072 (2023.02); H10N 30/086 (2023.02)] 9 Claims
OG exemplary drawing
 
1. A layered body comprising:
a ceramic substrate formed of polycrystalline ceramic and having a supporting main surface, and
a piezoelectric substrate formed of a piezoelectric material and having a bonding main surface in contact with the supporting main surface,
wherein at the supporting main surface, a mean of grain sizes of the polycrystalline ceramic is 0.5 μm or more and less than 15 μm,
a standard deviation of the grain sizes is less than 1.5 times the mean,
the polycrystalline ceramic is not formed of the piezoelectric material, and
a residual stress at the supporting main surface of the ceramic substrate formed of the polycrystalline ceramic is −300 MPa or more and 300 MPa or less.