Study On Preparation, Electrical, Optical Properties Of Vanadium Oxide Thin Films For Micro-bolometer

Vanadium oxide is an ideal heat sensitive material in microbolometer for its high temperature resistance coefficient（TCR）and proper sheet resistance.At present,there are countless studies on the preparation method and parameter optimization of vanadium oxide film.It is significant to prepare vanadium oxide films by combining multiple factors at the same time.To address this issue,this thesis focused on the following tasks.（1）The microstructure and photoelectric properties of vanadium oxide films prepared by DC magnetron sputtering were investigated with respect to the oxygen-argon ratio,substrate temperature,sputtering current and VO_x/V/VO_x interlayer sputtering time.The results showed that oxygen-argon ratio reduction,substrate temperature increment,sputtering current increment or V interlayer sputtering time increment substrate temperature increment or sputtering current increment were conducive to the reduction of the square resistance of films,because the concentration of V3d conductive electrons decreased.The trend of TCR is more complex,the higher TCR,the higher film activation energy.（2）The effects of substrate temperature,oxygen-argon ratio,sputtering time,and working gas flow on the electric properties of vanadium oxide thin films were analyzed by orthogonal experiments.Then,combined with mean and variance analysis and XPS analysis,the degree to the electrical properties was obtained:within the control range,working gas flow>substrate temperature>oxygen-argon ratio>deposition time.Finally,the optimal parameters for mixed-phase VO_x film preparation were obtained:sputtering current at 0.3 A,substrate temperature at 270°C,oxygen-argon ratio at 2.5%,deposition time at 20 min,working gas flow rate at 120 sccm,with TCR of-2.715%/K and sheet resistance of 1062.41 KΩ/□.（3）The impact of annealing temperature and time microstructure and electric properties of VO_x films were studied.The annealed films comprised V₆O₁₃,V₆O₁₁,V₂O₅and VO₂ phases.The sheet resistance decreased significantly with annealing temperature increment,accompanied by an apparent temperature-thermal hysteresis effect.Moreover,TCR exhibited an initial increase followed by a decrease trend.Furthermore,increasing annealing time was found to be beneficial for producing vanadium oxide films with lower sheet resistance.