CMOS-Integrable Piston-Type Micro-Mirror Array for Adaptive Optics Made of Mono-Crystalline Silicon using 3-D Integration

This paper presents a novel CMOS-compatible fabrication process and evaluations of a micro mirror array (MMA) made of mono-crystalline silicon (m-Si) for adaptive optic (AO) applications. The m-Si mirror layer is transfer bonded from a silicon-on-insulator (SOI) donor wafer with adhesive wafer bonding towards an intermediate patterned polymer spacer layer and clamped with metal plating. We present a CMOS compatible, bond alignment-free fabrication scheme offering the potential for high air gap distances between substrate and mirrors and we show first measurements of the fabricated mirrors.