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

Abstract

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 d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">31</sub> and the d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33</sub> coefficients of AlN to attain high electromechanical coupling (k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ), low motional resistance, and a limited lithographic control of the resonance frequency. k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> > 3.4%, a mechanical quality factor larger than 2400, and >10% lithographic variation of the center frequency were demonstrated.