Micromachined Uncooled SixGeyO1-x-y Microbolometer Integrated Metasurface for Uncooled Infrared Detection

This paper presents a study of metasurface integrated uncooled infrared (IR) silicon germanium oxide (Si-Ge-O) microbolometers for Long Wavelength Infrared (LWIR) detection. The inclusion of the metasurface permits engineering the IR absorptance with respect to wavelength. Absorption by the metasurface eliminates the need for a ¼-wave resonant cavity under the microbolometer. In addition, the metasurface can significantly improve the electrical performance of the temperature-sensing layer. Experimental results show an increase in the Temperature Coefficient of Resistance (TCR) and a decrease in the resistivity of the amorphous Si-Ge-O films. These parameters scale with the periodicity and area fraction of the metasurface. The voltage noise power spectral density was reduced by annealing the devices in vacuum. The measured responsivity and detectivity approached 10⁴ V/W and 10⁹ cm Hz^1/2/W to filtered blackbody infrared radiation.