Large-aperture electromagnetically actuated MEMS Fabry-Perot filtering chips for visible spectral imaging
Kui Zhou, Xialei Jing, Fei Wang, Haochuan Liu, Hao Jia, Wei Zhang, Yiting Yu
Abstract
Benefitting from the inherent merits of tiny volume, customizable performance, good system compatibility and high-yield production, micro-electro-mechanical-system-based Fabry-Perot filtering chip (MEMS-FPFC) with a large aperture size gives a feasible way for the realization of miniaturized spectral imagers which can serve in many civilian and military scenarios. Although the aperture size of MEMS-FPFCs in mid-wave and long-wave infrared has reached to the centimeter scale, that of visible wavelength (VIS) MEMS-FPFC is always unsatisfied which is mainly limited by micromachining stress, especially in the thin films. In this work, we propose a large-aperture electromagnetically actuated MEMS-FPFC based on Si 3 N 4 supporting membrane for VIS spectral imaging, which is designed with the assistance of multi-field coupling simulation model. A low-stress wafer-scale bulk micromachining process is developed to guarantee the high-quality and high-yield production for the aimed VIS MEMS-FPFCs. Finally, by the strictly controlling and rationally allocating the film stress of multi-layer film stack, VIS MEMS-FPFCs with 6 mm aperture size are thus developed, which can be tuned bidirectionally and continuously in 612-678 nm waveband with a good linear response of better than 95%. The achieved VIS MEMS-FPFCs can be utilized to construct miniaturized spectral imagers directly, aiming for such applications as intelligent agriculture, environmental protection and industrial inspection.