Near 6-GHz Sezawa Mode Surface Acoustic Wave Resonators Using AlScN on SiC

Surface Acoustic Wave (SAW) devices featuring Aluminum Scandium Nitride (AlScN) on a 4H-Silicon Carbide (SiC) substrate, offer a unique blend of high sound velocity, low thermal resistance, substantial piezoelectric response, simplified fabrication, as well as suitability for high-temperature and harsh environment operation. This study presents high-frequency SAW resonators employing AlScN thin films on SiC substrates, utilizing the second SAW mode (referred to as the Sezawa mode). The resonators achieve remarkable performance, boasting a K
$^{\mathbf{2}}$
value of 5.5% at 4.7 GHz and a maximum Bode-Q (Q
$_{\mathbf{max}}$
) of 911 at 4.3 GHz, outperforming previous AlScN SAW devices. Additionally, a SAW resonator with a 0.96
$\mu$
m wavelength attains 5.9 GHz frequency with K
$^{\mathbf{2}}$
of 4.0% and Q
$_{\mathbf{max}}$
of 762. Our study underscores the potential of the AlScN on SiC platform for advanced radio-frequency applications.2024-0075