阴极真空弧源沉积氟化类金刚石薄膜的结构与性能研究

采用脉冲磁过滤阴极真空弧源沉积系统(FCVA)在单晶硅基片上制备了含氟量不同的一系列氟化类金刚石膜(a-C:F).重点研究了氟掺杂对非晶态碳基薄膜结构、机械性能和疏水性能的影响.薄膜的成分和结构采用X射线光电子能谱仪(XPS)和激光拉曼光谱(Raman)进行了表征,薄膜表面形貌和粗糙度采用原子力显微镜(AFM)进行了分析.使用纳米压痕仪测量了薄膜硬度,纳米划痕仪测量了膜基结合力.采用躺滴法测量薄膜与双蒸水之间的接触角来评价其疏水性能.结果表明,随着CF4流量的逐渐增加,薄膜的氟化程度逐渐增强,膜中最大氟含量达45.6 at%;薄膜呈典型的类金刚石状结构,但薄膜的无序化程度增强;由于-CFn+的刻蚀,薄膜表面更加致密化、粗糙度逐渐减小.薄膜的机械性能良好,硬度在12GPa以上.薄膜的疏水性能得到增强,与双蒸水之间的最大接触角达106°,接近于聚四氟乙烯(PTFE,110°).

Structure and Properties of Fluorinated Diamond-like Carbon Films Synthesized by Cathodic Vacuum Arc Source Technology

Fluorinated diamond-like carbon (a-C: F) films with different fluorine content were grown on silicon (100) substrate by pulse filtered cathodic vacuum arc source technology (FCVA). Influences of the fluorine incorporation on the various properties of the amorphous carbon based film were especially emphasized, including its microstructure, its mechanical properties and the hydrophobicity. The film composition and structure were successively characterized by X-ray photoelectron spectroscope (XPS) and laser Raman scattering spectroscope. Surface morphology and roughness were analyzed by atomic force microscope (AFM). Hardness and scratch resistance were measured by nano-indentation and nano-scratch, respectively. Water contact angles were measured by the sessile drop method. As a result, with the increase of CF₄ flow rate in the feed gas, fluorine content was gradually increased to the film, the maximum fluorine content, 45.6 at% in the film was obtained. Raman spectra indicate that these films possess a diamond-like structure. The addition of fluorine to the amorphous carbon based film has a critical influence on its properties. The film surface becomes smoother due to the etching behavior of --CF⁺_n. Hardness and the scratch resistance results show that these films have fairly good mechanical properties, the nano-hardness is all above 12GPa. The hydrophobicity of this film is evidently improved, with the contact angle of 106° of double-stilled water, approaching that of polytetrafluoroethylene (110°).