A High Q Value ScAlN/AlN-Based SAW Resonator for Load Sensing

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This article presents a high quality factor (Q) load sensor based on Sc0.2Al0.8N/aluminum nitride (AlN)-on-silicon surface acoustic wave (SAW) resonator. Finite element method (FEM) analysis is performed to predict the resonance frequency and the wave propagation mode. A high-Qof 7200 at the parallel resonance frequency (fₚ) of 447.50 MHz is measured for Sc0.2Al0.8N/AlN configured SAW resonator on a silicon substrate. Experimental values for variation of series resonance frequency (Δ fₛ) and variation offₚ(Δ fₚ) are found to be −75.3 and −186.8 kHz with variation of applied force(Δ F) = 4.155N, operating in the analyzed range. The linear approximation of measured frequency variations under force isΔ fₛ/F = -12.7kHz/N andΔ fₚ/F = -46.2kHz/N. Moreover, the force sensitivities for this sensor are −28.4 and −103.2 ppm/N forfₛandfₚ, respectively. This high-Qscandium-doped AlN (ScAlN)/AlN-based SAW resonator exhibits high sensitivity, demonstrating that the structure can be used as load sensors in industrial applications such as manufacturing, medical, grocery, and automotive industries.