Focused Guided Surface Acoustic Waves in 30% Scandium Aluminum Nitride on Silicon Carbide

Slow-on-fast piezoelectric platforms, which describe the relationship between the phase velocity of a piezoelectric material to its substrate, have facilitated the development of guided surface acoustic wave (SAW) devices. Scandium aluminum nitride (ScAlN) alloy thin films, having a lower phase velocity and higher electromechanical coupling $\left( {k_t^2} \right)$ compared to aluminum nitride (AlN), allows for the implementation of strongly confined surface acoustic waves on silicon carbide. Simultaneously, focusing interdigitated transducers (FIDTs) have enabled a wavelength-scale mode confinement, enabling compact form factor phononic devices. This work presents a comprehensive quantitative analysis of acoustic delay lines and performance metrics using standard and focusing IDTs.