TY - GEN
T1 - High Frequency Strip-Type Solidly-Mounted Shear Mode Bulk Wave Resonator Using X-LT
AU - Kadota, Michio
AU - Ishii, Yoshimi
AU - Tanaka, Shuji
N1 - Publisher Copyright:
© 2020 IEEE.
PY - 2020/9/7
Y1 - 2020/9/7
N2 - The common materials of bulk acoustic wave (BAW) resonators are AlN and ScAlN. For a wider bandwidth, the Sc to Al ratio in ScAlN is increased up to 40%, but the Q factor often deteriorates and the impedance (Z) ratio does not improve significantly. For better filter performance, this study investigated monocrystalline LiTaO3 (LT) as a piezoelectric material for a high frequency strip type thickness shear mode (TS) solidly mounted resonator (SMR). We selected the SMR instead of a film BAW resonator (FBAR) with a cavity, because the suspended ultrathin LT plate is fragile. The strip type TS mode SMR is composed of two Al electrodes, a 2.0 µm thick X LT plate, an Al electrode, eight layers of SiO2 and Ta film (4+4 layers) and a 350 µm thick Si substrate from the top. The fabricated SMR shows a center frequency of 1 GHz, a bandwidth of 6.7% and an Z ratio of 62 dB. The temperature coefficients of frequency (TCF) at series and parallel resonance are as good as - 17 and -34 ppm/°C, respectively.
AB - The common materials of bulk acoustic wave (BAW) resonators are AlN and ScAlN. For a wider bandwidth, the Sc to Al ratio in ScAlN is increased up to 40%, but the Q factor often deteriorates and the impedance (Z) ratio does not improve significantly. For better filter performance, this study investigated monocrystalline LiTaO3 (LT) as a piezoelectric material for a high frequency strip type thickness shear mode (TS) solidly mounted resonator (SMR). We selected the SMR instead of a film BAW resonator (FBAR) with a cavity, because the suspended ultrathin LT plate is fragile. The strip type TS mode SMR is composed of two Al electrodes, a 2.0 µm thick X LT plate, an Al electrode, eight layers of SiO2 and Ta film (4+4 layers) and a 350 µm thick Si substrate from the top. The fabricated SMR shows a center frequency of 1 GHz, a bandwidth of 6.7% and an Z ratio of 62 dB. The temperature coefficients of frequency (TCF) at series and parallel resonance are as good as - 17 and -34 ppm/°C, respectively.
KW - BAW resonator
KW - GHz
KW - Impedance ratio
KW - SMR
KW - Strip type shear mode
KW - TCF
KW - X LiTaO3
UR - http://www.scopus.com/inward/record.url?scp=85097883668&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85097883668&partnerID=8YFLogxK
U2 - 10.1109/IUS46767.2020.9251827
DO - 10.1109/IUS46767.2020.9251827
M3 - Conference contribution
AN - SCOPUS:85097883668
T3 - IEEE International Ultrasonics Symposium, IUS
BT - IUS 2020 - International Ultrasonics Symposium, Proceedings
PB - IEEE Computer Society
T2 - 2020 IEEE International Ultrasonics Symposium, IUS 2020
Y2 - 7 September 2020 through 11 September 2020
ER -