Uncooled SIxGEyO1-x-y Microbolometer Stack for LWIR Detection


This paper presents design, fabrication, characterization, and noise reduction of two uncooled Si0.622Ge0.298O0.08 microbolometer stacked in a single pixel. Each microbolometer captures a portion of the spectrum across the long wavelength infrared region (LWIR) and the combined structure was optimized to maximize the total absorptance, transmittance, and reflectance of the individual surfaces with Frequency Selective Surface (FSS). The inclusion of the FSS on the bottom microbolometer permits engineering the IR absorptance with respect to wavelength. While the top microbolometer utilizes the need for a -wave resonant cavity under the microbolometer. In addition, the metasurface can significantly improve the electrical performance of the temperature-sensing layer. 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 108 cm Hz1/2/W for the bottom microbolometer with FSS.

Meeting Name

33rd IEEE International Conference on Micro Electro Mechanical Systems, MEMS 2020 (2020: Jan. 18-22, Vancouver, BC, Canada)


Mechanical and Aerospace Engineering

Research Center/Lab(s)

Center for Research in Energy and Environment (CREE)


The project was supported by National Science Foundation, Grant Nos. 1509589 and 1653792.

Keywords and Phrases

IR detection; Metasurface; Microbolometer; Noise; Si-Ge-O

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International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version


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Publication Date

22 Jan 2020