A high fill-factor IR bolometer using multi-level electrothermal structures

In this paper we report the design, fabrication, and performance of a high fill-factor uncooled IR (Infrared) bolometer using thin-film titanium resistors sandwiched in a surface-micromachined silicon oxynitride membrane (50 /spl mu/m /spl times/50 /spl mu/m). This bolometer structure comprises multi-level electrothermal structures, which allow almost 92% fill factor. From this multi-layered structure, thermal isolation can be independently optimized without sacrificing IR absorbing area. Initial measurements show a thermal time constant of 12 msec, a responsivity of 1600 V/W, and a detectivity of D*=5/spl times/10/sup 8/ cm/spl radic/(Hz)/W.