Photothermal deflection study of V/V2O5 alternating layers structure: effect of annealing atmospheres on thermal and optical properties

Abstract

High sensitivity uncooled microbolometers are necessary to meet the needs of the next generation of infrared detectors, and vanadium oxide thin films are the potential candidates for uncooled microbolometers due to their high temperature coefficient of resistance (TCR) at room temperature. It is, however, very difficult to deposit vanadium oxide thin films having a high temperature coefficient of resistance because of the process limits in microbolometer fabrication. We present a fabrication method for vanadium oxide thin films. Through the formation of a vanadium oxide VxOy thermometer thin films with thickness of 95 nm prepared by sputter-depositing nine alternative layers of V2O5 and V of thicknesses of 15 and 5 nm, respectively. Two samples of vanadium oxide mixed phase are characterized in this work and compared to a not annealed sample, the first sample is annealed at 300°C for 30 min in O2 and the second in N2 atmosphere. The results show that annealing atmosphere has an effect on microstructure, optical, and thermal properties of the mixed phase. Comparing to our previous work, we have reached in this work successful results with vanadium oxide sample having both high TCR and low resistivity.