Self-aligned 1.14-GHz vibrating radial-mode disk resonators

A new fabrication methodology that allows self-alignment of a micromechanical structure to its anchor(s) has been utilized to achieve vibrating radial-contour mode micromechanical disk resonators with record resonance frequencies up to 1.14 GHz and measured Q's at this frequency >1,500 in both vacuum and air. In addition, 733-MHz versions have been demonstrated with Q's of 7,330 and 6,100 in vacuum and air, respectively. For these resonators, self-alignment of the stem to exactly the center of the disk it supports allows balancing of the resonator far superior to that achieved by previous versions (where separate masks were used to define the disk and stem), allowing the present devices to retain high Q while achieving frequencies in the GHz range for the first time.