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

摘要

This article presents a high quality factor (inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${Q}$ /tex-math/inline-formula) load sensor based on Scsub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"0.2/subAlsub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"0.8/subN/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-inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${Q}$ /tex-math/inline-formula of 7200 at the parallel resonance frequency (inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${f}_{p}$ /tex-math/inline-formula) of 447.50 MHz is measured for Scsub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"0.2/subAlsub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"0.8/subN/AlN configured SAW resonator on a silicon substrate. Experimental values for variation of series resonance frequency (inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${Delta } {f}_{s}$ /tex-math/inline-formula) and variation of inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${f}_{p}$ /tex-math/inline-formula (inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${Delta } {f}_{p}$ /tex-math/inline-formula) are found to be ?75.3 and ?186.8 kHz with variation of applied force inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"$({Delta } textit {F)} = 4.155$ /tex-math/inline-formula N, operating in the analyzed range. The linear approximation of measured frequency variations under force is inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${Delta } {f}_{s}/{F} = -12.7$ /tex-math/inline-formula kHz/N and inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${Delta } {f}_{p}/{F} = -46.2$ /tex-math/inline-formula kHz/N. Moreover, the force sensitivities for this sensor are ?28.4 and ?103.2 ppm/N for inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${f}_{s}$ /tex-math/inline-formula and inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${f}_{p}$ /tex-math/inline-formula, respectively. This high-inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" tex-math notation="LaTeX"${Q}$ /tex-math/inline-formula scandium-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.