Optimization of S1 Lamb wave resonators with A10.8Sc0.2N

We demonstrate the optimized design of Al_0.8Sc_0.2N-based S₁ Lamb wave resonators. The S₁ mode shows a phase velocity of over 20,000 m/s, and an electromechanical coupling factor of over 7% can be achieved using the enhancement of the AIN piezoelectric characteristics by Sc doping. To exploit the high phase velocity region with thickness/lambda (h/λ) less than 0.3, a clean spectral response can be obtained by utilizing the double-IDT electrode configuration. The electrode coverage can significantly suppress the spurious modes, and high order modes free resonance has been achieved by utilizing 20% electrode coverage design. Although Sc-doping in AIScN film causes a slight decrease in phase velocity, significant enhancement of the electromechanical coupling coefficient provides potential for high frequency and large bandwidth applications.