Fabrication and characterization of high-Q silicon nitride membrane resonators

Silicon nitride membranes are a powerful and ubiquitous optomechanical resonator technology, enabling high mechanical Q, low optical loss, and enhanced optomechanical coupling via a panoply of strain-, phononic-, and photonic-crystal engineering techniques. Fabrication and characterization of silicon nitride membranes has become a form of tacit knowledge in optomechanics research groups. Here we present a video run-through of the design, fabrication, and characterization of a contemporary silicon nitride membrane resonator (specifically, a centimeter-scale Si3N4 nanoribbon supporting $Q>10^8$ torsion modes). Our tutorial can serve as a starting point or refresher for practitioners in the field.