Fabrication and Characterization of High-Q Silicon Nitride Membrane Resonators

Silicon nitride membranes are a widely used optomechanical resonator platform, offering high mechanical Q, low optical loss, and enhanced optomechanical coupling using a panoply of strain, phononic-crystal, and photonic-crystal engineering techniques. Despite their ubiquity, fabrication and characterization of silicon nitride membranes often rely on tacit knowledge shared between research groups. This article presents a detailed video walk-through of the design, fabrication, and characterization of a contemporary silicon nitride membrane resonator (specifically, a centimeter-scale Si3N4 nanoribbon supporting torsional modes with Q-factors exceeding 10⁸ at room temperature). The protocol covers finite element simulation, wafer- and chip-scale processing, and optical lever-based readout. Special attention is given to photolithographic patterning, dry- and wet-etching, device handling, and ringdown measurement. The tutorial is intended as both a practical entry point for newcomers and a reference for experienced groups replicating or adapting similar devices. All procedures are demonstrated in standard university cleanroom and benchtop environments.