微/纳米复合多层金刚石自支撑膜的制备及应力研究

Preparation of micro/nano composite multi-layered free-standing diamond film and evaluation of its stress

利用大功率DC Arc Plasma Jet CVD装置,采用Ar-H2-CH4混合气体为气源,通过优化工艺参数,在多晶钼衬底上制备出了多层复合金刚石自支撑膜。利用扫描电镜(SEM)、X射线衍射(XRD)、激光拉曼谱(Raman)对膜体进行表征,结果显示,多层膜体的组织结构体现了微米金刚石与纳米金刚石的典型特征;复合金刚石自支撑膜具有光滑的表面,微米层与纳米层间呈相互嵌套式的界面;此外,利用激光拉曼谱分析了多层膜中的内应力状态,研究发现,多层膜中各层膜体具有不同的内应力状态,内应力沿膜体生长方向有明显变化,呈现出从压应力到拉应力的变化过程。

A multi-layered free-standing diamond film was fabricated by optimizing the deposited parameters, with high power DC arc plasma jet chemical vapor deposition equipment. The substrate for deposition was polycrystalline molybdenum. The fed gases were a mixture of Ar, H2 and CH4. Then the multi-layered films were analyzed using SEM, XRD and Raman spectroscopy. The results show that the multi-layered film structure reveals classical characteristics of the microcrystalline and nanocrystalline diamond. The surface of the multi-layered film is very smooth, and the interface between microsized columnar layer and nanocrystaUine layer is nested by each other. Moreover, Raman spectrum was also used to investigate the internal stress of multilayered diamond film. It shows that the internal stress varies along the growth direction of the film, indicating a change of compressive to tensile stress in the film.