Design and simulation of advanced surface micromachined micromirror devices for telescope adaptive optics applications

This paper describes the design, fabrication, modeling, surface characterization, and simulation of advanced surface micromachined micromirror devices that are optimized for adaptive optics applications. Design considerations and fabrication capabilities are presented. Simulation of adaptive optics performance of unique Flexure-Beam (FBMD) and Axial-Rotation Micromirror Devices (ARMD) is performed for many common aberrations. These devices are fabricated in the state-of-the-art four-level planarized polysilicon process available at Sandia National Laboratories known as the Sandia Ultra-planar Multi-level MEMS Technology (SUMMiT). This enabling process permits the development of micromirror devices with near-ideal characteristics that have previously been unrealizable in standard three-layer polysilicon processes. This paper describes such characteristics as elevated address electrodes, array wiring techniques, planarized mirror surfaces using Chemical Mechanical Polishing (CMP), unique post-process metallization, and the best active surface area to date.