Amorphous GexSi1-xOy:H Microbolometers with High Responsivity

In current work, we report the design, fabrication and characterization of a-Ge_0.85Si_0.15O_0.0236:H microbolometers. A sandwich structure of silicon nitride-silicon germanium oxide-silicon nitride was used to form the sensing layer. Due to moderately high resistivity of a-Ge_0.85Si_0.15O_0.0236 layer, the current flow through the sensing layer was made vertically and through the absorber layer laterally. Forming gas passivation was done at 250degC to reduce the 1/f-noise. A high responsivity of 1.05 times 10⁴ V/W along with a high temperature coefficient of resistance of -4.8%/K was obtained at room temperature and in vacuum from a 40 mum times 40 mum pixel. The lowest value of thermal conductance achieved was 4 times 10^-8 W/K.