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Bidoul_33551500_2020.pdf
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- Abstract
- In the context of investigation of the use of MEMS (Micro Eletro-Mechanical Systems) in CubeSat missions, several possible applications are reviewed. Focusing on infrared sensing, a proof of concept for an amorphous Germanium based bolometer is presented. Prior to the device micro-fabrication process, extensive optical and thermal characterization of Germanium is performed. A temperature coefficient of resistance of 0.38 %/K is measured. The relevant thermal and optical models are built and used for optimization of the structure. More specifically, optical simulations performed using the Transfer Matrix Method demonstrate two highly selective, thin film interference based optical stacks, with >97% absorptance in the targeted LWIR spectrum. Sensitivity studies give insights for the compensation of optical stack layer thicknesses deviation during fabrication process. Thermal finite element simulation (COMSOL) investigates illumination under a flat-plate blackbody, highlighting the contribution of conductive and convective losses with respect to the radiative heat source. Fabricated devices resistance variation is characterized under in situ infrared illumination: the results qualitatively confirm the insights from the simulations, however with lower dynamic response than those reported in state of the art.