TY - GEN
T1 - LT/Quartz HAL SAW Resonator with Large LT Thickness over Severalfold Wavelength
AU - Kadota, Michio
AU - Tanaka, Shuji
N1 - Funding Information:
This research and development work was partly supported by the SCOPE #175002002.
Publisher Copyright:
© 2019 IEEE.
PY - 2019/10
Y1 - 2019/10
N2 - A Hetero Acoustic Layer (HAL) surface acoustic wave (SAW) device is a new class of SAW device using a thin LT or LN layer rigidly mounted on a substrate. In the past reports, the LT layer was as thin as 0.13-0.221 (<0.7 μm for 1 GHz devices) to obtain a high impedance ratio (e.g. >80 dB), but this range of thickness is not easy to control in mass-production. In this study, we investigated the design space at larger LT thickness by FEM simulation. In the design space near the conventional one, in-band ripples and/or out-of-band spurious responses are generated. If a 1.4 times thicker Al or Cu electrode is combined with a LT layer thicker than a specific value (1λ for Al and 4λ for Cu), however, the ripples and spurious responses almost disappear and the deterioration of impedance ratio is limited. On the other hand, by using further thicker electrodes, a higher mode of SAW is excited preferentially at 2-2.6 times higher frequency than the fundamental mode.
AB - A Hetero Acoustic Layer (HAL) surface acoustic wave (SAW) device is a new class of SAW device using a thin LT or LN layer rigidly mounted on a substrate. In the past reports, the LT layer was as thin as 0.13-0.221 (<0.7 μm for 1 GHz devices) to obtain a high impedance ratio (e.g. >80 dB), but this range of thickness is not easy to control in mass-production. In this study, we investigated the design space at larger LT thickness by FEM simulation. In the design space near the conventional one, in-band ripples and/or out-of-band spurious responses are generated. If a 1.4 times thicker Al or Cu electrode is combined with a LT layer thicker than a specific value (1λ for Al and 4λ for Cu), however, the ripples and spurious responses almost disappear and the deterioration of impedance ratio is limited. On the other hand, by using further thicker electrodes, a higher mode of SAW is excited preferentially at 2-2.6 times higher frequency than the fundamental mode.
KW - HAL SAW
KW - LiTaO
KW - SAW resonator
KW - higher mode
KW - impedance ratio
KW - quartz
KW - thick LT
KW - thick electrode
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U2 - 10.1109/ULTSYM.2019.8926135
DO - 10.1109/ULTSYM.2019.8926135
M3 - Conference contribution
AN - SCOPUS:85077584541
T3 - IEEE International Ultrasonics Symposium, IUS
SP - 1223
EP - 1226
BT - 2019 IEEE International Ultrasonics Symposium, IUS 2019
PB - IEEE Computer Society
T2 - 2019 IEEE International Ultrasonics Symposium, IUS 2019
Y2 - 6 October 2019 through 9 October 2019
ER -