Characterization of Microbolometer Based on Nanopolycrystal VO2 Thin Films

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