Design and characteristics of a-Si-based micro-bolometers with shared-anchor structure in vacuum packaged systems

This paper reports the design and fabrication of an a-Si-based micro-bolometer using a new pixel design to enhance the fill factor through use of shared-anchor structures, which enable a one-anchor-per-unit-pixel scheme. The proposed micro-bolometer was fabricated in 64 x 64 arrays with 25 mu m pixel size. The design increased the fill factor by 10 % compared to that of the unshared-anchor design owing to the mechanical flatness of the shared-anchor structure. The fabricated bolometer showed enhancements in responsivity from 1.08 x 10(5) to 1.23 x 10(5) V/W and an increased thermal time constant of 10 ms at a 30 Hz chopping frequency. From the measurement results, there were no mechanical, electrical, or thermal crosstalk problems between adjacent pixels with the increased fill factor compared to the unshared-anchor design.