Characterization of microbolometer based on nanopolycrystal VO2 thin films

A new nanopolycrystalline vanadium dioxide (VO₂) thin film has been prepared. The thin film is fabricated by reaction-ion sputtering and post-annealing process .The average grain size is 8-10 nm, the phase transition temperature drops down to 35degC, and the temperature coefficiency of resistance (TCR) is -6~7%/K in semiconductor zone. However, the average grain size of conventional microstructure VO₂ is 1~2 mum and TCR is about -2%/K. 64times2 linear uncooled microbolometers with pixel size 50 mumtimes50 mum have been fabricated based on the nanopolycrystalline V02 thin films and conventional microstructure VO₂ thin films. The characteristics of the micrbolometer arrays are investigated in the spectral region of 8- 12 mum. The test indicates that the performance of the sensor based on nanopolycrystalline VO₂ is nearly 3 times higher than that based on conventional microstructure VO₂ thin film.