An A1 Mode Resonator at 12 GHz using 160nm Lithium Niobate Suspended Thin Film

This paper demonstrates a 160 nm thick first- and third-order antisymmetric mode Lithium Niobate resonator. The presented device maintains feature sizes on the order of micrometers by thinning the piezoelectric resulting in a first-order mode at 11.77 GHz through direct scaling of state-of-the-art design approaches. Thinning leverages an Argon-based low-power physical etch, with attention paid specifically to surface roughness. The fabricated device demonstrates a first-order antisymmetric series resonant frequency of 11.77 GHz with an electromechanical coupling of 23.6% and a mechanical quality factor of 148 for a Figure of Merit of 35.1. In addition, the resonator's third-order antisymmetric mode achieves an electromechanical coupling of 3.7% and a mechanical quality factor of 66 at a frequency of 34.7 GHz.