Design and Fabrication of S₀ Lamb-Wave Thin-Film Lithium Niobate Micromechanical Resonators

Abstract

Commercial markets desire integrated multifrequency band-select duplexer and diplexer filters with a wide fractional bandwidth and steep roll-off to satisfy the ever-increasing demand for spectrum. In this paper, we discuss the fabrication and design of lithium niobate (LN) thin-film S 0 Lamb-wave resonators on a piezoelectric-on-piezoelectric platform. Filters using these resonators have the potential to fulfill all the above requirements. In particular, we demonstrated one-port highorder S 0 Lamb-wave resonators with resonant frequencies from ∼400 MHz to ∼1 GHz on a black rotated y-136 cut LN thin film. The effective electromechanical coupling factor (k 2 ef f ) ranges from 7% to 12%, while the measured quality factor ranges from 600 to 3300. The highest k 2 ef f × Q achieved on this chip is 194, significantly surpassing contour mode resonators manufactured in other technologies.[2014-0280]

High-quality lithium niobate photonic crystal nanocavities

“…On the other hand, the demonstrated devices exhibit strong coupling between the optical cavity mode and the mechanical motion of the device structures, with which we were able to characterize the rich nanomechanical motions of the device. We observed mechanical modes with frequency up to 1.003 GHz with a f · Q product of 1.47 × 10 12 Hz that is comparable to state-ofthe-art LN micromechanical devices 5,6,24,53 . The devices exhibit a single-photon/single-phonon optomechanical coupling rate of |g o | 2π = 71 kHz that is comparable to most other optomechanical crystals [54][55][56][57][58] , although our devices are not specifically designed for optomechanical applications.…”

“…Detailed characterization (Fig. 6(c)) shows that this mode exhibits an intrinsic mechanical Q of 1465, corresponding to a f · Q product of 1.47 × 10 12 Hz, which is comparable to state-of-the-art LN micromechanical resonators 5,6,24,53 .…”

Micromachined Resonators: A Review

“…The process differs from the above as device is fabricated from the wafer itself as the material cannot be deposited as a thin film. MEMS resonators fabricated from LiNbO 3 have been shown to exhibit much lower insertion losses compared to AlN resonators [ 174 , 175 , 176 , 177 ].…”

Chip-scale cavity optomechanics in lithium niobate

“…The high mechanical Qs result from achieving a minimal radius (<100 nm) of the supporting silica pedestal to dramatically suppress the clamping loss. Consequently, the mechanical modes exhibit frequency-quality ( f  ·  Q ) products of 2.0 × 10 12 and 3.6 × 10 12  Hz, which are the highest among the recent reported LN mechanical microresonators394041.…”