自组织分层金属掺杂类金刚石薄膜的研究进展

近年来,研究学者发现在沉积过程中,某些金属元素掺杂类金刚石薄膜时能够形成一种特殊的自组织分层纳米结构,这种纳米结构克服了人为调控多层薄膜的工艺复杂性及局限性,同时赋予了薄膜更加优异的性能。主要综述了国内外对金属掺杂类金刚石薄膜中自组织分层结构的影响因素、形成机理等方面的研究现状。详细阐述了金属类型及含量、沉积条件(脉冲频率、基体偏压、气流比、沉积温度、沉积时间)、沉积方法等参数对自组织分层结构的生成及富金属层厚、富碳层厚、层数等尺寸的作用规律。重点介绍了离子重排机理、金属催化机理、强离子辐照诱导机理和靶中毒机理四种自组织分层结构形成机理的特点,并探讨了目前研究工作中存在的一些不足,如自组织分层结构的形成机理尚不清晰。上述四种机理模型均具有一定的局限性,且如何设计工艺参数实现自组织分层结构的内在调控仍是一个科学难点。针对这些问题,提出了自组织分层结构碳基薄膜的未来研究方向。

Research Progress in Metal-doped Diamond-like Carbon Films with Self-organized Multilayer Structure

In recent years, scientists have found that some metal elements doped diamond-like carbon (Me-DLC) films can form a special self-organized layered nanostructure in the deposition process. This nanostructure can overcome the complexity and limitation of artificially controlled preparation for multilayer films, and endow the films more excellent performance. Here, the formation mechanism and influencing factors of the self-organized multilayer (SOM) structure in Me-DLC films were mainly illustrated. The effects of metal types, metal contents, deposition conditions (pulse frequency, substrate bias, flow ratio, deposition temperature and deposition time) and deposition methods on the formation of SOM structures and dimensions of metal-rich layer thickness, carbon-rich layer thickness, layer number, etc. were elaborated. Four types of the formation mechanisms for the SOM structure consisting of the ion rearrangement, the metal catalysis, the induction by strong ion irradiation and the target poisoning were emphatically introduced. Moreover, some deficiencies in the current research work were also discussed. For instance, the formation mechanism of the SOM structure was unclear yet. All of the four mechanisms mentioned above had limitations, and it was still a scientific difficulty to realize the internal control of the SOM structure by designing process parameters. On this basis, the further researches of the SOM structure in carbon-based films were also proposed.