Spurious Free SAW Resonators on LiNbO3/SiO2/ Quartz Substrate for Wideband Application

SummaryIn this work, the LiNbO
3
/SiO
2
/Quartz substrate (LiNbO
3
-on-quartz, LNOQ) was fabricated in wafer scale using ion-cut process. 3D finite element analysis was used to design this structure. The 36°YX quartz was chosen to achieve good confinement of acoustic energy. The 42°YX LN was chosen to get large electromechanical coupling coefficient (k
²
) and suppress the Rayleigh mode. The 4-inch LNOQ wafer shows high film thickness uniformity of 597.8 nm ±1.8%. The fabricated shear horizontal surface acoustic wave (SH-SAW) resonator shows large k
²
of 28.1% and high-quality factor of 959, thanks to the good confinement of acoustic energy and low RF loss of quartz. Besides, the resonators show clean out of band response due to the moderate acoustic velocity of quartz.