Membrane structure FBAR fabricated with highly c-axis oriented AlN film based on platinum electrode

Aluminum nitride (AlN) thin film bulk acoustic resonator was fabricated using silicon bulk micromachining technique with highly c-axis oriented piezoelectric cell. AlN piezoelectric films were deposited on both platinum (Pt) and gold (Au) bottom electrodes under optimized sputtering condition for comparison. The measurement results of X-ray diffraction, scanning electron microscope, and atomic force microscope show that Pt is more available for the deposition of c-axis orientation of the AlN film. The fabricated resonator was measured in a one-port configuration using a network analyzer, and finally achieved an effective electromechanical coupling coefficient (K_eff ² ) of 3.75%, series quality (Q_s) and parallel quality (Q _p) of 101.8 and 79.7, respectively