Plasmonic Metamaterial Absorber for Multispectral MWIR Microbolometers

Abstract:
In this work, we present simulation results for a fabricated plasmonic metamaterial absorber (PMA) consisting of an Al/SiO2/Al stack with periodically patterned top layers for multispectral MWIR microbolometers as well as corresponding Fourier-transform infrared spectroscopy (FTIR) measurements. The measurements show absorptances of 92 % to 96 % for different wavelengths in the MWIR region. Moreover, the results indicate a linear relationship between center wavelength of the absorption peaks and lateral metal-insulator-metal (MIM) micropatch size, which enables a specific selection of the absorption wavelength depending on the intended application. The choice of material system, the deposition methods and patterning processes are suitable for the integration in the existing Fraunhofer IMS’s scalable nanotube microbolometer technology. The fabrication process is CMOS-compatible and carried out on 8-inch wafers.