5 Ghz lithium niobate MEMS resonators with high FoM of 153

This paper reports on the demonstration of a new class of super-high frequency (SHF) microelectromechanical system (MEMS) resonators operating in the 5 GHz range. SHF resonances have been achieved using the first order antisymmetric (A1) mode, which features a phase velocity exceeding 10000 m/s in ion-sliced and suspended Z-cut Lithium Nio-bate (LiNbO3) thin films. The fabricated device has demonstrated a high electromechanical coupling (k
_t
²
) of 29% and a high quality factor (Q) of 527 simultaneously. Consequently, this work marks the first time that MEMS resonators at SHF were demonstrated with an extremely high figure of merit (FoM= kt
²
Q) of 153. The SHF operation and high FoM of these A1 mode devices have showcased their potential as the key building blocks for future SHF front-end filters and multiplexers.