Effects of substrate temperature and intermediate layer on adhesion, structural and mechanical properties of coaxial arc plasma deposition grown nanodiamond composite films on Si substrates
Effects of substrate temperature and intermediate layer on adhesion, structural and mechanical properties of coaxial arc plasma deposition grown nanodiamond composite films on Si substrates
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DOI：
10.1016/j.surfcoat.2021.127185
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发表时间：
2021-04-30
影响因子：
5.4
通讯作者：
Yoshitake, Tsuyoshi
中科院分区：
文献类型：
--
作者：
Ali, Ali M.;Egiza, Mohamed;Yoshitake, Tsuyoshi
在未处理的硅衬底上低温制造纳米金刚石膜，其是优选的衬底并且广泛用于工业中，可以扩展纳米金刚石膜的应用，例如在生物传感和小型化技术中。为了实现这一目标，纳米金刚石薄膜在硅衬底上由于界面处原子相互扩散不足而导致的弱粘附力是一个需要克服的严重问题。在本研究中，同轴电弧等离子体沉积（CAPD）生长的纳米金刚石薄膜在低温下在硅衬底上。衬底温度是CAPD纳米金刚石薄膜生长过程中的一个重要参数。结果表明，随着衬底温度的升高，薄膜发生软化，薄膜与衬底界面处的原子相互扩散被激活，导致界面处SiC的形成。另一方面，在室温下直接在硅上制备的薄膜由于附着力差和残余应力高而剥落。因此，采用在升高的衬底温度下制造的中间层来改善纳米金刚石膜在硅衬底上的粘附强度。这样，可以促进界面处的原子互扩散，并缓解薄膜中的残余应力。在第二阶段中，在不同温度下在中间层上制备膜。结果表明，在低温下制备的顶层膜具有独特的力学和结构性能。通过应用这种策略，可以在Si衬底上制造几微米的硬质纳米金刚石膜，而不容易剥离。
Low-temperature fabrication of nanodiamond films on untreated silicon substrates, which are preferred substrates and widely employed in industry, can extend nanodiamond film applications, for instance in biosensing and miniaturization technologies. For its realization, the weak adhesion of nanodiamond films on silicon substrates due to insufficient atomic interdiffusion at the interfaces is a serious issue that needs to be overcome. In the present study, coaxial arc plasma deposition (CAPD) grown nanodiamond films were fabricated at low temperatures on silicon substrates. The effects of the substrate temperature, which is an important parameter in the CAPD nanodiamond film growth process, were structurally and physically investigated. It was found that the films softened with increasing substrate temperature and atomic interdiffusions at interfaces between the films and substrates were activated, which resulted in the formation of SiC at the interfaces. On the other hand, the films fabricated directly on silicon at room temperature were exfoliated due to the poor adhesion and high residual stress. Consequently, intermediate layers that were fabricated at elevated substrate temperatures were employed to improve the adhesion strength of nanodiamond films on silicon substrates. This way, the atomic interdiffusion at the interfaces could be promoted and the residual stress in the films was relieved. In the second stage, the films were fabricated on the intermediate layers at different temperatures. It has shown that the top layer films fabricated at low temperature gained distinctive mechanical and structural properties. By applying this strategy, several micrometres of hard nanodiamond films can be fabricated on Si substrates without easily being peeled off.