Transverse Resonance Suppression of AlN-based Surface Acoustic Wave Resonators using Trench Structure

In recent years, aluminum nitride (AlN) has attracted considerable attention for its high acoustic velocity and stable piezoelectric properties at high temperatures, making it a promising material for high-performance SAW sensors. However, simulation studies have identified higher-order transverse Lamb wave modes in AlN-based SAW resonators. These spurious modes reduce the sensor’s quality (Q) factor and cause frequency interference, affecting the signal-to-noise ratio and transmission range. This study effectively excites the piston mode by etching part of the piezoelectric material in the gap region to form a trench structure. Simulation results show that the trench design effectively creates a waveguide structure, suppressing transverse spurious modes and improving the overall device performance. The proposed trench structure presents a viable approach for advancing AlN-based SAW wireless sensor technology.