Transverse-Mode Spurious Suppression Technique for Surface Acoustic Wave Resonator with Zero Temperature Coefficient of Frequency on a SiO 2 /Al/LiNbO 3 Structure

• Published in: Japanese Journal of Applied Physics Vol. 51; no. 7S; p. 7
• Main Authors: Nakanishi, Hidekazu, Nakamura, Hiroyuki, Tsurunari, Tetsuya, Fujiwara, Joji, Hamaoka, Yosuke, Hashimoto, Ken-ya
• Format: Journal Article
• Language: English
• Published: 01.07.2012
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.51.07GC15

In this paper, we describe a suppression technique of transverse-mode spurious responses for a surface acoustic wave (SAW) resonator with a near zero temperature coefficient of frequency (TCF) on a SiO 2 /Al/LiNbO 3 structure. We investigated the thinning of SiO 2 on the dummy electrode region and studied how the transverse-mode responses change with remaining SiO 2 thickness h on the dummy electrode region. As the results, we clarified that the remaining SiO 2 thickness h on the dummy electrode region has an optimum value and could suppress the transverse-mode spurious responses completely when H and h are set at 0.35 λ and 0.20 λ, respectively. It was demonstrated that the selective SiO 2 removal technique is effective to suppress transverse-mode spurious responses for SAW resonators employing the SiO 2 /Al/LiNbO 3 structure for a wide range of SiO 2 thicknesses, provided that the SiO 2 thickness at the dummy electrode region is adjusted properly.