Advanced design of microbolometers for uncooled infrared detectors

Uncooled infrared detectors are applied widely in both civilian and military. Recently, novel microbolometers composing of two planes located at different levels were proposed to improve the performance of the detectors. In this paper, such two-layer microbolometers were simulated by finite element analysis. Results reveal that when SiO2 film is utilized as the isolating and supporting material located at the lower bridge plane, the temperature rise of the pixel reaches 3∼5 times higher than those in the conventional one-layer microbolometers, and the maximum IR absorptance increases for about 40%. Therefore, these two-layer microbolometers are helpful for significantly improving the thermal and optical properties. However, their structural stability turns poor. Consequently, the mechanical properties for such two-layer microbolometers should be enhanced in practical applications.