Electrode Optimization for Ring-Shaped AIN Piezoelectric MEMS Resonators

High-performance resonators play a critical role in timing, frequency control, and signal processing applications, serving as fundamental components in modern communication, sensing, and navigation systems. Device performance is highly sensitive to structural design. Conventional electrode with full coverage often results in non-uniform electric fields, limiting quality factor$(Q)$. This work proposes a ring-shaped AlN piezoelectric resonator on an SOI substrate, featuring a symmetric radial sector electrode design. This configuration enhances electromechanical coupling by optimizing field-strain overlap, enabling efficient excitation of high order modes. Experimental results demonstrate the sector electrode resonator achieving a$Q$factor of 1975, representing a 40% improvement over conventional designs. AlN resonator was fabricated with 6 inch SOI wafer and the characteristics of the resonator was validated by BVD equivalent circuit fitting, these findings confirm that optimized electrode geometry offers an effective and scalable pathway to realizing high quality factor AlN MEMS resonators.