基于AFM的不导电金属铟薄膜的表面微观特征分析

Deposition and Microstructures of Non-Conductive Indium Coatings on PMMA Plate:An Atomic Force Microscopy Study

利用电子束蒸发镀膜方法在PAMM上制备了金属铟薄膜,通过方块电阻测量和原子力显微镜(AFM)表面形貌的分析,结果表明:铟薄膜的电阻值随着薄膜生长厚度增加而减小;薄膜生长初始阶段基体表面形成了岛状不连续膜,表面粗糙度随膜厚增加而增加,此时薄膜不导电;当膜层厚度生长到120 nm时,薄膜形成了下层连续上层为小孔洞的结构,表面粗糙度在此厚度附近降低较明显;随着薄膜继续生长,薄膜表面无论是水平方向还是垂直方向,岛与岛相连形成十分光滑的膜层,此时薄膜电阻迅速降低到3Ω,薄膜导通。

The non-conductive indium coatings were deposited by e-beam evaporation on polymethylmethacrylate（ PMMA） plate. The impact of the thickness on the microstructures and electrical properties of the indium thin films was investigated with atom force microscopy. The preliminary results show that the coverage or thickness strongly affected the surface morphology and electrical properties of the In-coating. To be specific,in the initial growth stage,the 3-D isolated indium islands formed on the substrate and the films were non-conductive. As the thickness increased,the isolated islands grew into a continuous film and the surface roughness decreased. Growing thicker than 120 nm,the sheet resistance and surface roughness markedly decreased and randomly distributed pores covered the surfaces of compact films. The smooth compact indium coating,~ 160 nm in thickness,was found to be conductive with a sheet resistance of ~ 3 Ω/□.