Scalable nanotube microbolometers for uncooled thermal imaging

The scalability of Fraunhofer IMS’s nanotube microbolometer technology for uncooled thermal imaging is demonstrated. Thermal insulation of the microbolometers is realized by means of vertically oriented nanotubes arranged underneath the sensor membrane. Thus, thermal insulation is decoupled from the latter, allowing for a variable scaling of the microbolometer, independently of its thermal insulation. Key parameters as electro-optical responsivity, noise, NETD and thermal time constant are presented for pixel pitches varying between 17 μm, 12 μm, 8.5 μm and 6 μm with the latter value being close to the fundamental optical limit in the LWIR, but full electro-optical functionality being maintained.