Determination of full material constants of ScAlN thin film from bulk and leaky Lamb waves in MEMS-based samples

The full material constants of a 40% Sc-AlN thin film were systematically determined. First, 4 kinds of MEMS resonators and a Lamb wave resonator were used to determine the material constants as much as possible. The other unknown material constants together with the material constants which needed more accurate estimation were determined based on ultrasonic microspectroscopy and parameter fitting. The phase velocity versus frequency (v-f) characteristics of A₀ and S₀ mode leaky Lamb waves in a self-suspended ScAlN film were measured using an ultrasonic microscope, and then theoretical v-f characteristics were fitted to the measured ones by tuning the material constants as parameters.