Zero Temperature Coefficient of Frequency Surface Acoustic Wave Resonator for Narrow-Duplex-Gap Application on SiO2/Al/LiNbO3 Structure

• Published in: Jpn J Appl Phys Vol. 50; no. 7; pp. 07HD13 - 07HD13-4
• Main Authors: Nakanishi, Hidekazu, Nakamura, Hiroyuki, Tsurunari, Tetsuya, Fujiwara, Joji, Hamaoka, Yosuke, Hashimoto, Ken-ya
• Format: Journal Article
• Language: English
• Published: The Japan Society of Applied Physics 01.07.2011
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.50.07HD13

In this paper, we describe a zero temperature coefficient of frequency (TCF) surface acoustic wave (SAW) resonator on a SiO 2 /Al/LiNbO 3 structure. We studied the dependence of TCF and electromechanical coupling factor ($K^{2}$) of shear-horizontal (SH) SAW on SiO 2 thickness, where the SiO 2 shape control technique is applied to suppress spurious responses caused by the Rayleigh mode. As a result, we could realize a high performance SAW resonator having moderate $K^{2}$ (8%) and zero TCF with complete suppression of the Rayleigh-mode spurious response. We demonstrated that the SiO 2 shape control technique is effective for suppression of the Rayleigh-mode spurious response in the SAW resonator using the SiO 2 /Al/LiNbO 3 structure for a wide range of SiO 2 thicknesses. We also revealed the applicability of the SiO 2 /Al/LiNbO 3 structure to SAW duplexers with a narrow duplex gap.