Single-Layer Thin-Film Lithium Niobate Out-of-Plane Actuators

This work presents a novel out-of-plane actuator that is composed of a single thin-film piezoelectric layer. The devices are implemented based on a platinum-coated silicon substrate to which a lithium niobate (LN) film is bonded. The out-of-plane movement of the single-layer piezoelectric film is enabled by the unique piezoelectric properties of LN, while a relatively large movement is achieved due to the large coupling coefficients of the film combined with the optimized alignment of the actuation arms to proper LN crystalline orientation. The process flow designed for the fabrication of these devices is detailed, and the preliminary test results are presented. In situ SEM imaging was conducted to quantify the amount of displacement, which is observed to be 4µm for an applied voltage of ±25V in a 250x250 µm2 device.