Microfabrication of large area high-stress silicon nitride membranes for optomechanical devices

In view of the integration of membrane resonators with more complex MEMS structures, we developed a general fabrication procedure for circular shape SiN${}_x$ membranes using Deep Reactive Ion Etching (DRIE). Large area and high-stress SiN${}_x$ membranes were fabricated and used as optomechanical resonators in a Michelson interferometer and in a Fabry-P'erot cavity. The measurements show that the fabrication process preserves both the optical quality and the mechanical quality factor of the membrane.