Near 6-GHz Sezawa Mode Surface Acoustic Wave Resonators Using AlScN on SiC
Xingyu Du, Nishant Sharma, Zichen Tang, Chloe Leblanc, Deep Jariwala, Roy H. Olsson
Abstract
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<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {2}}$ </tex-math></inline-formula> value of 5.5% at 4.7 GHz and a maximum Bode-Q (Q<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm {max}}$ </tex-math></inline-formula>) of 911 at 4.3 GHz, outperforming previous AlScN SAW devices. Additionally, a SAW resonator with a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.96~\mu $ </tex-math></inline-formula>m wavelength attains 5.9 GHz frequency with K<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\mathrm {2}}$ </tex-math></inline-formula> of 4.0% and Q<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm {max}}$ </tex-math></inline-formula> of 762. Our study underscores the potential of the AlScN on SiC platform for advanced radio-frequency applications. [2024-0075]