High-Q SAW Resonators Based on High-Crystallinity AlScN-AlN-Sapphire Substrate

This work reports on surface acoustic wave (SAW) piezoelectric resonators with high quality factor (Q) based on high-crystallinity aluminum scandium nitride (AlScN) thin films. The properties of surface acoustic wave modes were analyzed using finite element modeling (FEM) simulations. SAW resonators based on different AlScN composite substrates were fabricated and measured. Due to good crystallinity (FWHM < 1°) of the AlScN thin film, high quality factor over 1000 has been demonstrated based on the AlScN/AlN/sapphire composite substrate, which proves sapphire substrate is a good candidate to enable high
$Q$
in AlN/AlScN SAW resonator development.