TY - GEN
T1 - Polarization inverted two layer ScAlN thin film resonator fabricated by applying external electric field
AU - Ishii, Naoki
AU - Yanagitani, Takahiko
N1 - Funding Information:
ACKNOWLEDGMENT This work was supported by JST CREST (No. JPMJCR20Q1), JST FOREST, and KAKENHI (Grant-in-Aid for Scientific Research B, No.19H02202, No.21K18734).
Publisher Copyright:
© 2022 IEEE.
PY - 2022
Y1 - 2022
N2 - ScAlN has high piezoelectricity and ferroelectricity. BAW filters with polarization inverted multilayer structure allow the further improvement of the power durability. In this study, by growing the Al-polar ScAIN film on the N-polar film, the polarization inverted two-layer ScAIN thin films resonator were fabricated. Unusual N-polar ScAIN film was obtained by a polarization inversion treatment to the as-grown usual Al-polar films. Polarity of the ScAlN films was determined by a press test. kt2 of as-grown Al-polar ScAIN and N-polar ScAlN films after the polarization treatment (-190 V (2.0 MV/cm) at 300 °C) were estimated to be 7.7% and 5.6%, respectively. Because of an incomplete polarization inversion, kt2 in the film after polarization inversion treatment slightly decreased compared with the as-grown films. Second overtone mode excitation was observed at GHz range, and fundamental mode was suppressed.
AB - ScAlN has high piezoelectricity and ferroelectricity. BAW filters with polarization inverted multilayer structure allow the further improvement of the power durability. In this study, by growing the Al-polar ScAIN film on the N-polar film, the polarization inverted two-layer ScAIN thin films resonator were fabricated. Unusual N-polar ScAIN film was obtained by a polarization inversion treatment to the as-grown usual Al-polar films. Polarity of the ScAlN films was determined by a press test. kt2 of as-grown Al-polar ScAIN and N-polar ScAlN films after the polarization treatment (-190 V (2.0 MV/cm) at 300 °C) were estimated to be 7.7% and 5.6%, respectively. Because of an incomplete polarization inversion, kt2 in the film after polarization inversion treatment slightly decreased compared with the as-grown films. Second overtone mode excitation was observed at GHz range, and fundamental mode was suppressed.
KW - BAW
KW - ferroelectric
KW - polarization inverted multilayer
KW - ScAIN
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U2 - 10.1109/IUS54386.2022.9957918
DO - 10.1109/IUS54386.2022.9957918
M3 - Conference contribution
AN - SCOPUS:85143763351
T3 - IEEE International Ultrasonics Symposium, IUS
BT - IUS 2022 - IEEE International Ultrasonics Symposium
PB - IEEE Computer Society
T2 - 2022 IEEE International Ultrasonics Symposium, IUS 2022
Y2 - 10 October 2022 through 13 October 2022
ER -