Evaluation of V_0.75Ti_0.25O₂ Bolometer Thin Films Fabricated by MOD

Abstract

Ti-doped vanadium dioxide (V_0.75Ti_0.25O₂) thin films were fabricated by metal-organic decomposition (MOD). Precursor films were fabricated at a temperature of T_p = 300 ºC for 15 min in a N₂ atmosphere. Then, these precursor films were fired at T_f = 520~600 ºC for t_f = 15~45 min in a N₂ atmosphere. From X-ray diffraction (XRD) patterns of the fired films, diffraction peaks indicating VO₂(M) phase were observed with a wide range of T_f = 540~600 ºC. Furthermore, the peaks indicating VO₂(M) phase were also observed with a wide range of t_f = 15~45 min. Regarding the surface morphology of the films, the nanoparticles of 100~200 nm were densely packed. From R-T characteristics of the films, the phase transition with a rapid resistance change and hysteresis loop disappeared completely at T_f = 560~600 ºC. Relatively flat temperature dependence of the temperature coefficients of resistance (TCR) as high as -3.2~-6.2 %/K at the temperature range from 20 ºC to 80 ºC was obtained for the film fired at T_f = 580 ºC. From these experimental results, it was found that wide windows of firing conditions for fabricating V_0.75Ti_0.25O₂ thin film can be obtained in the MOD process.