Ultrafast Silicon Nanomembrane Microbolometer for Long-Wavelength Infrared Light Detection.

The microbolometer is the cornerstone device for imaging in the long-wavelength infrared range (LWIR) at room temperature. The state-of-the-art commercial microbolometers usually have a large thermal time constant (TTC) of over 10 ms, limited by their substantial device heat capacity. Moreover, the minimal pixel size of state-of-the-art bolometer is around 10 μm by 10 μm to ensure sufficient power absorption per pixel. Here, we demonstrate an ultrafast silicon nanomembrane microbolometer with a small heat capacity of around 1.9 × 10-11J/K, which allows for its operation at a speed of over 10 kHz, corresponding to a TTC of less than 16 μs. Moreover, a compact diabolo antenna is leveraged for efficient LWIR light absorption, enabling the downscaling of the active area size to 6.2 μm by 6.2 μm. Because of the complementary metal oxide semiconductor (CMOS)-compatible fabrication processes, our demonstration here may lead to a future high-resolution and high-speed LWIR imaging solution.