Comparison of V2O5 Microbolometer Optical Performance Using NiCr and Ti Thin-Films

The optical performance characteristics of vanadium-oxide microbolometer with on-top nichrome (NiCr) thin-film metal absorber layer are evaluated using numerical simulations. A thin-film NiCr metal is sputter deposited and its optical parameters are experimentally characterized over the long-wave infrared (LWIR) range 8-$12~\mu $ m. The optical performance of microbolometer with NiCr has been compared with titanium (Ti) and without any metal thin-film. The comparison indicates that the optical absorption response of NiCr device is nearly flat and has a broadband enhancement over the LWIR range. In addition, it shows large insensitivity to variations in air-gap and metal thin-film thickness, which permits for a large fabrication tolerance. In addition, the optimized air-gap devices show that the NiCr-based device has the smallest air-gap thickness, which can lead to short leg-length and mechanically robust device.