Self-locking vertical operation single crystal silicon micromirrors using silicon-on-insulator technology

Micro-opto-electro-mechanical systems (MOEMS) have been developed for a broad range of applications including: optical switching, optical data storage, imaging, bar code reading and beam steering for free-space optical communications. One vital component of these systems, the out-of-plane micromirror, is required for any redirection of light. The challenge for the design of these mirrors is to create an optically smooth and flat surface for producing minimum distortion reflections. If a micromirror scatters a significant amount of energy, then a higher power light source will be required reducing the efficiency and increasing the cost of the system. Typically, micromirrors fabricated through polycrystalline processes offer structural designs of multiple layers allowing for hinges to be created for out-of-plane operation. However, polycrystalline mirrors do not offer the flatness and smoothness that is achievable with single crystalline materials. Micromirrors made from single crystalline processes provide superior optical properties, but the complexity for designing out-of-plane structures is increased due to the single layer structural design requirement. To utilize the superior optical properties of single crystalline materials, we have designed single crystal silicon micromirrors using the micralyne generalized MEMS (MicraGEM) process with a novel latching system that allows the micromirrors to remain locked in a vertical position during operation