Cu膜的光学特性尺寸效应及最小连续膜厚研究

采用离子束溅射在K9玻璃基底上沉积了不同厚度的Cu膜，利用Lambda-900分光光度计，测量了波长为310 nm到1300 nm范围内Cu膜的反射率和透射率.选定波长为310、350、400、430、550、632、800、1200 nm时对薄膜的反射率、透射率和吸收率随膜厚变化的关系进行研究.同时，对Cu膜的光学常量也进行了讨论.结果显示，Cu膜的光学特性都有明显的尺寸效应.将波长为550 nm时的反射率和透射率随Cu膜厚度变化关系的交点对应厚度作为特征厚度, 该厚度可认为是金属Cu膜生长从不连续膜进入连续膜的最小连续膜厚.根据这一特征判据，离子束溅射沉积Cu膜样品的最小连续膜厚为33 nm.利用原子力显微镜观测了膜厚在特征厚度附近时Cu膜的表面形貌.

Size Effect of the Optical Properties and the Minimal Continuous Thickness of Copper Films

Cu films of different thickness were deposited on K9 glass using ion beam sputtering. The reflectance and transmittance of Copper films in the wavelength range from 310 nm to 1300 nm have been measured by Lambda-900 spectrophotometer. Relationships between reflectance, transmittance, absorptance and thickness of Cu films in the wavelength selected 310, 350, 400, 430, 550, 632, 800, 1200 nm have been discussed. The optical constants of Cu films have also been discussed.The results show that the optical properties of Cu films have obvious size effect. There is a point of intersection, which is located in the relationship curves of between reflectance, transmittance and thickness of Cu films at wavelength 550 nm. The corresponding thickness of this point of intersection can be thought of as the minimal continuous thickness of the growth of metallic films from discontinuous to continuous. According to this characteristic criterion, the minimal continuous thickness of Cu films prepared by ion beam sputtering is 33 nm. The topography images of Cu films near the minimal continuous thickness were observed by using atomic force microscopy (AFM).