AlN Two-Dimensional-Mode Resonators for Ultra-High Frequency Applications

In this letter, we present the first prototype of aluminum nitride two-dimensional-mode resonators (2DMRs) for operation in the ultra-high-frequency range. The 2DMRs in this letter are made of thick AlN films (5.9μm) and rely on both the d₃₁ and the d₃₃ coefficients of AlN to attain high electromechanical coupling (k_t² ), low motional resistance, and a limited lithographic control of the resonance frequency. k_t² > 3.4%, a mechanical quality factor larger than 2400, and >10% lithographic variation of the center frequency were demonstrated.