Up-Scaling Microacoustics: 20 to 35 GHz ALN Resonators with f • Q Products Exceeding 14 THz

This work presents an analysis of the first mmWaves-operating Cross-sectional Lamé Mode Resonators (CLMRs), investigating the intrinsic quality factor limit of the technology. By leveraging the Finite Element Modeling-simulated energy distributions in the piezoelectric and metal layer, an accurate matching of theoretical and experimental quality factor is achieved, thus identifying the main source of CLMR performance degradation in the 20 to 35 GHz frequency range. Furthermore, excellent quality factors are recorded, achieving the largest frequency and quality factor product (f
s
• Q = 14.4 THz) ever demonstrated on sputtered thin-films and among the largest ever reported for the microacoustic technology. In conclusion, the present results explore the feasibility of enabling mmWaves-operating CLMRs to extend the use cases of the microacoustic technology to a virtually new spectrum territory, while outlining design trade-offs aiming to maximize their quality factors.