Study of Thin Film LiNbO3 Laterally Excited Bulk Acoustic Resonators

• Published in: Journal of microelectromechanical systems Vol. 31; no. 2; pp. 217 - 225
• Main Authors: Yandrapalli, Soumya, Eroglu, Seniz Esra Kucuk, Plessky, Victor, Atakan, H. Baris, Villanueva, Luis Guillermo
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 5 GHz; 5G application; A1 mode; acoustic filters; Aluminum; bulk acoustic resonator (BAW); Bulk acoustic wave devices; Couplings; Electrodes; electromechanical coupling; Fabrication; k²t; Lamb wave; large bandwidth; Lithium niobate; Lithium niobates; Lithography; Mass production; microfabrication; Resonance; Resonant frequency; Resonators; RF MEMS; shear wave; Thin films
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2022.3143354

This work presents an in-depth study of simulation and measurement results of laterally excited shear bulk acoustic resonators (XBAR) in Lithium Niobate, at 5 GHz with high electromechanical coupling factor (<inline-formula> <tex-math notation="LaTeX">k_{t}^{2} </tex-math></inline-formula>) as high as 25%, and with impedances at resonance close to <inline-formula> <tex-math notation="LaTeX">2~\Omega </tex-math></inline-formula>. Loaded Quality factors of up to 340 and 150 are obtained at resonance and anti-resonance, respectively. Experimental00 dispersion behaviors of main mode and spurious are presented. Several geometric parameters affecting resonator performance are studied in order to improve figure of merits (FoM) of the device for 5G filter applications. The modified fabrication process presented shows a high yield of over 90% of devices which can be scalable for mass production of high frequency, sub-6 GHz, wide band filters. [2021-0202]