Experimental study of the acoustoelastic effect on the sensitivity of surface acoustic wave sensors

This paper reports, for the first time, the sensitivity deterioration phenomenon of surface acoustic wave (SAW) sensors for distortion, load, or pressure monitoring. Assuming that the acoustoelastic effect causes this phenomenon and that the effect can be characterized with two coefficients for stress components parallel and perpendicular to SAW propagation direction, we developed a method to quantify these coefficients. We found that the coefficient for the stress parallel to the propagation direction causes sensitivity deterioration for Sc doped AlN (ScAlN) film on 6H-silicon carbide (6H-SiC) substrate structures. This result also indicates the possibility of effectively improving the sensitivity by taking advantage of the effect.