Theoretical investigation of Lamb wave characteristics in AlN/3C-SiC composite membranes

Cubic silicon carbide (3C-SiC) layer can provide advantages of high frequency and high quality factor for Lamb wave devices due to the superior properties of high acoustic velocity and low acoustic loss. In this study, Lamb wave propagation characteristics in composite membranes consisting of a c -axis oriented aluminum nitride (AlN) film and an epitaxial 3C-SiC (100) layer are investigated by theoretical calculation. The lowest symmetric mode Lamb wave propagating along the [011] direction exhibits a phase velocity higher than 10000 m/s and an electromechanical coupling coefficient above 2% in the AlN/3C-SiC multilayered membranes.