5–24 GHz high <i>f-Q</i> product multi-mode surface acoustic wave resonances in LiNbO3/SiC heterostructures

Abstract

This work reports multi-mode surface acoustic wave resonances in a lithium niobate on silicon carbide (LiNbO3/SiC) heterostructure, achieving high resonant frequency-quality factor (f-Q) products over a broad frequency range from 5 to 24 GHz. By employing a 600-nm-thick LiNbO3 functional layer, multiple high-velocity acoustic modes with wavelengths (λ) ranging from 0.24 to 0.8 μm are effectively confined. This strong energy confinement arises from the large acoustic impedance mismatch between the LiNbO3 thin film and the high-phase-velocity SiC substrate, enabling the selected modes to consistently exhibit high f-Q products exceeding 1012 with a maximum f-Q product of 1.6 ×1013 achieved for the SH1 mode at 10.6 GHz. The operating frequency is further extended to the millimeter-wave regime at 24.45 GHz with a shorter λ of 0.24 μm while maintaining an excellent f-Q product of 6 ×1012. These results highlight the strong potential of the LiNbO3/SiC platform for the development of frequency-scalable, high-performance acoustic devices for next-generation communication systems.