High-Frequency Sezawa Mode Surface Acoustic Wave Resonators Using Boron-Doped AlScN on SiC and Sapphire Substrates

Authors:
Publisher website
Google Scholar
Abstract
This letter presents Sezawa mode surface acoustic wave (SAW) resonators based on 500 nm boron-doped aluminum scandium nitride (Al ${}_{\mathbf {1-x-y}}$ B ${}_{\mathbf {x}}$ Sc ${}_{\mathbf {y}}$ N), AlBScN thin films co-sputtered from AlB and Sc targets onto sapphire and silicon carbide (SiC) substrates. The devices exhibit series resonance frequencies ranging from 4.3 GHz to 7.6 GHz. Atomic Force Microscopy (AFM) revealed smooth film surfaces, with root mean square roughness values of 0.65 and 0.54 nm on sapphire and SiC, respectively. X-ray diffraction (XRD) $\omega $ -scans around the wurtzite (002) reflection confirmed a highly c-axis oriented film exhibiting a full width at half maximum of 0.96° on sapphire. Electrical measurements revealed a maximum Sezawa mode velocity of 6748 m/s on SiC, while the sapphire-based device achieved a peak parallel resonance quality factor ( $Q$ ${}_{\mathbf {p}}$ ) of 1400. These results demonstrate the suitability of AlBScN for high-frequency, high-performance resonator applications.[2025-0143]

This publication has 17 references indexed in Scilit: