TY - JOUR
T1 - Surface Acoustic Wave Resonators with Hetero Acoustic Layer (HAL) Structure Using Lithium Tantalate and Quartz
AU - Kadota, Michio
AU - Ishii, Yoshimi
AU - Tanaka, Shuji
N1 - Funding Information:
Manuscript received July 16, 2020; accepted November 15, 2020. Date of publication November 20, 2020; date of current version April 26, 2021. This work was supported in part by the Ministry of Internal Affairs and Communications under Grant SCOPE #175002002. (Corresponding author: Shuji Tanaka.) The authors are with the Department of Robotics, Tohoku University, Sendai 980-8579, Japan (e-mail: mkadota. . ems.mech.tohoku.ac.jp; yunoki. . ems.mech.tohoku.ac.jp; tanaka. . ems.mech.tohoku.ac.jp). Digital Object Identifier 10.1109/TUFFC.2020.3039471 Fig. 1. Different layer structures of SAW device. (a) TC-SAW device with uneven SiO2 surface. (b) TC-SAW device with planarized SiO2 surface. (c) SAW device using a thin piezoelectric layer. (d) SAW device using acoustic multilayer reflector. (e) SAW device using thin piezoelectric and SiO2layers.
Publisher Copyright:
© 1986-2012 IEEE.
PY - 2021/5
Y1 - 2021/5
N2 - This article reports a new concept of surface-acoustic-wave (SAW) resonator, which uses shear horizontal (SH) wave confined in a thin LiTaO3 (LT) layer supported by a quartz (Qz) substrate. The LT layer is 35-50°YX LT, and the quartz substrate is 35-60°Y90°X Qz. A negative temperature coefficient of frequency (TCF) of the SH SAW in the LT layer is compensated by the quartz substrate, which shows a wide range of positive TCF depending on the crystalline orientation. Excellent TCFs of 2 and -10 ppm/°C were measured for the series and parallel resonance frequencies, respectively. The strong confinement of the SH SAW in the LT layer results in the best level of resonance characteristics ever reported. The measured impedance ratio reached 84 dB. On the other hand, spurious waves other than the SH SAW are not confined in the LT layer due to the unique properties of quartz, which results in spurious-free characteristics throughout a wide frequency range.
AB - This article reports a new concept of surface-acoustic-wave (SAW) resonator, which uses shear horizontal (SH) wave confined in a thin LiTaO3 (LT) layer supported by a quartz (Qz) substrate. The LT layer is 35-50°YX LT, and the quartz substrate is 35-60°Y90°X Qz. A negative temperature coefficient of frequency (TCF) of the SH SAW in the LT layer is compensated by the quartz substrate, which shows a wide range of positive TCF depending on the crystalline orientation. Excellent TCFs of 2 and -10 ppm/°C were measured for the series and parallel resonance frequencies, respectively. The strong confinement of the SH SAW in the LT layer results in the best level of resonance characteristics ever reported. The measured impedance ratio reached 84 dB. On the other hand, spurious waves other than the SH SAW are not confined in the LT layer due to the unique properties of quartz, which results in spurious-free characteristics throughout a wide frequency range.
KW - Impedance ratio
KW - lithium tantalate
KW - quartz
KW - spurious response
KW - surface acoustic wave (SAW)
KW - temperature coefficient of frequency (TCF)
UR - http://www.scopus.com/inward/record.url?scp=85096840285&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85096840285&partnerID=8YFLogxK
U2 - 10.1109/TUFFC.2020.3039471
DO - 10.1109/TUFFC.2020.3039471
M3 - Article
C2 - 33216714
AN - SCOPUS:85096840285
SN - 0885-3010
VL - 68
SP - 1955
EP - 1964
JO - Transactions of the IRE Professional Group on Ultrasonic Engineering
JF - Transactions of the IRE Professional Group on Ultrasonic Engineering
IS - 5
M1 - 9265194
ER -