Performance Enhancement of CMOS Microbolometer With Metal-Insulator-Metal Absorbers

In this paper, the Metal-Insulator-Metal-based (MIM) plasmonic metamaterial structure is designed to improve the detectivity of the CMOS microbolometer based on the standard technology. The MIM structure consists of three layers: Al/SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> /Al and the materials used can be found in the integrated circuit process. Simulation results show that this MIM structure can effectively enhance the infrared absorption efficiency of microcalorimeter in the range of 7 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">~ 13μ m</tex> Optical experiments on the fabricated device demonstrate that with the addition of MIM structure, the average detectivity (D*) of the microbolometer is increased by 52.13%, reaching <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2.17× 10⁹</tex> cm HZ 1/2 /W at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">9.8μ m</tex> . These performance improvements can make the microbolometer play a more important and stable role in medical diagnosis, environmental monitoring, security monitoring and so on.