离子能流密度对类金刚石薄膜成膜的影响

Influence of Energy Flow Density of Ion Current on Growth of Diamond-like Carbon Thin Films

着重讨论了离子轰击能量影响类金刚石薄膜成膜过程的机理 ,特别引入了离子能流密度即在单位时间内成膜表面的单位面积上接收到的离子轰击能量的概念 ,这就能更加正确地解释离子轰击在成膜过程中所起的作用。采用了具有特色的等离子体分解碳氢化合物结合高能离子轰击基片的方法制备类金刚石薄膜。这种兼有PVD和CVD各自优点的PCVD方法 ,能独立地分别调节轰击基片的离子能量和离子流密度。实验结果表明 ,存在一个离子能流密度的阈值。超过该阈值 ,才能得到结构致密、均匀 ,与基片结合强度好 ,硬度很高的类金刚石薄膜 ,扫描电镜对膜层形貌的显微成像和维氏硬度测试展示了离子能流密度对成膜的影响。作为佐证 ,还对薄膜进行了喇曼光谱测试和分析。

This paper discusses mainly the effects and principle of bombarding energy of ions on the growth of diamond like carbon thin films.The author specially introduces a new concept:energy flow density of ion current,i.e.the accepted energy of the bombarding ions on the substrate surface in unit area and unit time.It can more correctly expose the function of the bombarding ions in the deposition process of the thin films.Method of decomposition of hydrocarbon combined with high energy ion bombardment of substrates with distinguishing features has been used in our laboratory.By means of so called PCVD method,which has both the advantages of the PVD and CVD the bombarding ion energy and the ion current flow density on the substrate can be independently adjusted.The experimental results showed that a threshold of the energy flow density of ion current exists for this PCVD method using the bombarding ions.Only beyond the threshold the diamond like carbon thin films with dense,homogeneous,hard surface and good binding to the substrate can be obtained.Morphological graphs of the films made by a scanning electron microscope and the Vicker's hardness tests obviously showed the influence of the energy flow density of ion current on the growth of the diamond like carbon thin films.In order to obtain additional evidences we analyzed the Raman shift spectra of the films.