Characterization of microbolometer based on nanopolycrystal VO2 thin films

Abstract

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.