Vanadium oxide (VOx) thin films elaborated by sol-gel method for microbolometer applications

Karslı, Kadir
Infrared detector technologies have been developing each day. Thermal detectors take great attention in commercial applications due to their low power consumption and low costs. The active material selection and the deposition of the material are highly important performance effective factors for microbolometer detector applications. In that sense, developing vanadium oxide (VOx) microbolometer active material by sol-gel method might be feasible approach to achieve good performance microbolometer detectors. In this study, vanadium oxide thin films are prepared by sol-gel method is deposited on silicon or silicon nitride wafers as active material by spin coating. The films are annealed under different hydrogen concentration of H2/N2 environments at 410 C for various hours to obtain desired oxygen phases of vanadium oxide thin films. After appropriate annealing step, V2O5 structured thin films are reduced to mixture of lower oxygen states of vanadium oxide thin films which contains V2O5, V6O13, and VO2. Finally, the performance parameters such as sheet resistance, TCR, and noise are measured to verify the quality of the developed vanadium oxide active layers for their use in microbolometers. The sheet resistances are in the range of 100 kΩ/sqr – 200 kΩ/sqr. The resistances are reasonable values around 100 kΩ under 20 µA bias, and the TCR values of the samples measured around 2%/C at room temperature (25 C). The measured noise of the films is higher than expected values, and the corner frequencies are more than 100 kHz. The results of the measurements show that it is possible to use sol-gel deposited vanadium oxide as a microbolometer active material after improving the noise properties of the material.


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Citation Formats
K. Karslı, “Vanadium oxide (VOx) thin films elaborated by sol-gel method for microbolometer applications,” M.S. - Master of Science, Middle East Technical University, 2012.