退火对IBED氧化钒薄膜结构和性能的影响

Influence of Annealing Conditions on Properties of Vanadium Oxide Films Prepared by Modified Ion Beam Enhanced Deposition

对离子束增强沉积(IBED)氧化钒薄膜作不同条件的退火,用X射线衍射分析薄膜的晶体结构;用电阻 温度测试分析了薄膜的热电阻温度系数。实验发现,沉积薄膜存在一个形成二氧化钒结构的临界结晶温度,该温度随薄膜制备时离子束增强沉积条件的不同而改变。退火温度低于临界结晶温度时,很难使薄膜结晶成二氧化钒结构;高于临界温度较多的退火或形成VO2结构后再长时间退火,都会使VO2多晶薄膜中的钒分解降价,使薄膜的结构退化、性能变差。IBED多晶VO2薄膜在室温附近的电阻温度系数可达到4%/K以上。

Different annealing conditions were adopted to anneal the vanadium oxidefilms prepared by modified Ion Beam Enhanced Deposition (IBED) method.An X- Ray Diffraction (XRD) was used to analyze the crystalline structure of the IBED films and the film resistance was tested with temperature change to measure its temperature coefficient of resistance (TCR). Experiments indicated that there existed a critical temperature for crystallization of VO_2, which varied with the different deposition conditions of the IBED method. It is very difficult to obtain VO_2 structure if the annealing temperature was lower than the critical temperature. If the temperature is much higher than the critical temperature or annealing time is too long, the valence of vanadium in VO_2 film will easily reduce from 4 to low value,which will result in the worse properties of the film.The TCR of the IBED VO_2 polycrystalline films annealed in appropriate condition could reach higher than 4%/K about the room temperature.