衬底负偏压对Ni-Mn-Ga形状记忆薄膜成分及形貌的影响

Effects of substrate negative bias on the composition and morphology of Ni-Mn-Ga shape memory thin films

采用能谱仪（EDS）和原子力显微镜（AFM）对不同衬底负偏压下射频磁控溅射法制备的Ni—Mn-Ga形状记忆薄膜进行了成分和形貌的分析。研究发现：当衬底负偏压在5～30V范围变化时，薄膜中的Ni含量随偏压的增加呈先减少后增加的趋势，在偏压为10V时，达到最小值52．84％（摩尔分数，下同）.Ga含量的变化趋势恰好与Ni相反，且在偏压为10V时达到最大值29．85％，而Mn含量变化不大，保持在17．00％左右；薄膜呈典型岛状（Volmer-Weber）模式生长，表面颗粒尺寸和均方根粗糙度都随衬底负偏压的增加而减小。

Ni-Mn-Ga shape memory thin films were prepared by radio-frequency magnetron sputtering at different substrate negative bias. The effects of substrate negative bias on the composition and morphology of Ni-Mn-Ga thin films were studied through EDS and AFM. The results indicate that Ni contents of the films decrease first and then increase with the increasing of substrate negative bias in the range of 5-30 V. The minimum of Ni content is 52.84% （mole fraction, sililarly hereinafter） at 10 V. The varying trend of Ga content is opposite to that of Ni and the maximum is 29.85% at 10 V. The Mn content varies slightly and remains at about 17.00%. Thin films grow in typical island mode （Volmer-Weber）. The particle size and root mean square roughness of the films surface both decrease with the increasing of the substrate negative bias at 5-30 V.