Enhancing Mechanical Stability of MEMS Resonator at Cryogenic Temperature Using Periodically Poled Thin Films

This work investigates the mechanical stability of periodically poled piezoelectric film (P3F) resonators at cryogenic temperatures. Lithium niobate P3F Lamb-mode resonators were experimentally characterized down to 13 K. Comparative measurements show that bilayer devices with identical per-layer thickness degrade below 93 K due to thermal stress, whereas trilayer devices exhibit a monotonic increase in quality factor (Q), reaching 720 at 13 K. The results highlight a unique advantage of the P3F platform: by increasing total film thickness, bending stiffness is enhanced, enabling robust operation across a wider cryogenic range. With further optimization, P3F devices demonstrate strong potential for ultra-low-temperature applications, including deep space exploration and quantum technologies.