超高温度系数V0.97W0.03 O2多晶薄膜的制备研究

将V₂O₅粉体与WO₃粉体均匀混合并压制成靶，用离子束增强沉积加后退火技术在SiO₂衬底上制备掺钨VO₂多晶薄膜.X射线衍射表明，薄膜取向单一，为VO₂结构的［002］相,晶格参数d比VO₂粉晶增大约0.34%；薄膜从半导体相向金属相转变的相变温度约28；室温(300 K)时的电阻-温度系数(TCR)可大于10%/K，是目前红外热成像薄膜TCR的四倍.W离子的半径大于V离子的半径，W的掺入在薄膜中引入了张应力,使薄膜相变温度降低到室温附近，是IBED V_0.97W_0.03O₂薄膜的室温电阻温度系数提高的原因. 关键词： 二氧化钒薄膜 薄膜掺杂 离子束增强沉积

Preparation of polycrystalline V0.97W0.03O2 thin films with ultra high TCR at room temperature

The W doped vanadium oxide film was deposited on the SiO₂ substrate by modified ion beam enhanced deposition (IBED) method. The V₂O₅ and WO₃ mixed powders, atom ratio of W/V being 3/97, were pressed as the sputtering target. After annealed in Ar or N₂ the polycrystalline IBED VO₂ film doped with tungsten was obtained. The annealed IBED V_0.97W_0.03O₂ film was orientated only to ［002］ of VO₂ structure, and the latice parameter d was larger than that of VO₂ crystal powder measured by X-ray diffraction. The results of resistance-temperature test showed that the phase transition temperature was decreased from 68℃ to 28℃. The thermal coefficient of resistance (TCR) was high up to 10 %/K at 300K. With the ionic radius of tungsten larger than the radius of vanadium, W⁶⁺ ion doping would induce a tension stress into the film. As a result, the transition temperature of the W-doped VO₂ films was decreased to the room temperature, and the TCR was increased greatly.