TY - JOUR
T1 - Characteristics of pure-shear mode BAW resonators consisting of (112̄0) textured ZnO films
AU - Yanagitani, Takahiko
AU - Kiuchi, Masato
AU - Matsukawa, Mami
AU - Watanabe, Yoshiaki
PY - 2007/8/1
Y1 - 2007/8/1
N2 - Thickness pure-shear mode film bulk acoustic wave resonators (FBARs) made of (112̄0) textured ZnO films have been fabricated. We also have fabricated FBAR structure consisting of two layers of the (112̄0) textured ZnO film with opposite polarization directions. This FBAR structure operated in second overtone pure-shear mode and allowed shear-mode FBARs at higher frequency. The effective electromechanical coupling coefficients keff2 of pure-shear mode FBAR and second overtone pure-shear mode FBAR in this study were found to be 3.3% and 0.8%, respectively. The temperature coefficient of frequency (TCF) of thickness extensional mode FBAR, pure-shear mode FBAR, and second overtone pure-shear mode FBAR were measured in the temperature range of 10-60°C. TCF values of -63.1 ppm/°C, -34.7 ppm/°C, and -35.6 ppm/°C were found for the thickness extensional mode FBAR, the pure-shear mode FBAR, and the second overtone pure-shear mode FBAR, respectively. These results demonstrated that pure-shear mode ZnO FBARs have more stable temperature characteristics than the conventional thickness extensional mode ZnO FBARs.
AB - Thickness pure-shear mode film bulk acoustic wave resonators (FBARs) made of (112̄0) textured ZnO films have been fabricated. We also have fabricated FBAR structure consisting of two layers of the (112̄0) textured ZnO film with opposite polarization directions. This FBAR structure operated in second overtone pure-shear mode and allowed shear-mode FBARs at higher frequency. The effective electromechanical coupling coefficients keff2 of pure-shear mode FBAR and second overtone pure-shear mode FBAR in this study were found to be 3.3% and 0.8%, respectively. The temperature coefficient of frequency (TCF) of thickness extensional mode FBAR, pure-shear mode FBAR, and second overtone pure-shear mode FBAR were measured in the temperature range of 10-60°C. TCF values of -63.1 ppm/°C, -34.7 ppm/°C, and -35.6 ppm/°C were found for the thickness extensional mode FBAR, the pure-shear mode FBAR, and the second overtone pure-shear mode FBAR, respectively. These results demonstrated that pure-shear mode ZnO FBARs have more stable temperature characteristics than the conventional thickness extensional mode ZnO FBARs.
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U2 - 10.1109/TUFFC.2007.439
DO - 10.1109/TUFFC.2007.439
M3 - Article
C2 - 17703672
AN - SCOPUS:34548133546
VL - 54
SP - 1680
EP - 1685
JO - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
JF - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
SN - 0885-3010
IS - 8
ER -