氩氧比与退火温度对磁控溅射VO2薄膜结构与电学性能的影响

Influence of Argon-Oxygen Ratio and Annealing Temperature on the Structures and Electric Properties of VO2 Thin Films Prepared by Magnetron Sputtering

摘要:

采用反应直流磁控溅射法,通过调控溅射过程中的氩氧比,在石英玻璃衬底上制备了氧化钒薄膜,研究了溅射气氛及后处理条件对其微结构与电学性能的影响。经450和500℃退火,薄膜中易形成VO₂,而550℃退火时薄膜中会形成大量非4价的钒氧化物。薄膜在较高温度500℃下退火时结晶度增加,但薄膜颗粒之间的间隙更为明显,导致电阻率显著提高；同时其电阻率-温度曲线的热滞回线宽度较窄,在加热过程中相转变温度较高。当氩氧比中氧含量增加时,沉积的VO₂薄膜中生成了少量非4价的钒氧化物。结果表明,反应磁控溅射法制备的氧化钒薄膜的微结构、电阻率、相变温度等特性与氩氧比和后退火温度密切相关。

Abstract:

Vanadium oxide films were prepared on quartz glass substrates by reactive DC magnetron sputtering by adjusting the argon-oxygen flowing ratio in sputtering process, and the effect of sputtering atmosphere and post-treatment conditions on micro-structures and electrical properties of the films were investigated. Being annealed under 450 and 500℃ is beneficial to the formation of VO₂, nevertheless, a large number of non-4-valent vanadium oxides appear in the films when the annealing temperature increases to 550℃. The crystallization of the films increases after they were annealed at 500℃, however, the cracks between the particles of films become more obvious, resulting in a significant increase in the resistivity of the films; meanwhile, the width of thermal hysteresis loop of the resistivity-temperature curve is narrower, and the phase transition temperature is higher during the heating process. A small amount of non-4-valent vanadium oxides were formed in the deposited VO₂ films when the oxygen content in the argon-oxygen mixtures increases. The results show that the micro-structure, resistivity and phase transition temperature of VO₂ films prepared by reactive magnetron sputtering are closely associated with the argon-oxygen ratio of sputtering atmosphere and post-annealing.