Growth of ultrananocrystalline diamond films in an Ar-rich CH4/H2/Ar atmosphere with varying H2 concentrations
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摘要: 利用微波等离子气相沉积法在5%~20%的氢气浓度下，制备出了超纳米金刚石薄膜（UNCD）。利用扫描电子显微镜、XRD、表面轮廓仪及拉曼光谱研究了氢气浓度对超纳米金刚石薄膜的微结构、形貌、以及相组成的影响。结果表明,随着氢气浓度的增加，晶粒粒径及粗糙度都明显增加变大；在不大于10%的氢气浓度气氛下，可以发现晶粒粒径下降到6nm，甚至更低；即便氢气浓度达到20%，晶粒粒径仍然小于10nm。讨论了在富氩气氛下沉积的UNCD的实验结果以及沉积机制。这种极其光滑的UNCD薄膜有望在医疗，声表面波器件以及微机电系统，尤其是在重载和恶劣环境下作为超级密封材料的应用。Abstract: Ultrananocrystalline diamond (UNCD) films were prepared by microwave plasma chemical vapor deposition using argon-rich CH4/H2/Ar plasmas with different H2 concentrations from 5 to 20%. The influence of the H2 concentration on the microstructure, morphology and phase composition of the UNCD films was investigated by SEM, XRD, surface profilometry and Raman spectroscopy. It is found that the grain size and surface roughness increase with the H2 concentration. The grain size of the UNCD is less than 6 nm when the H2 concentration is less than 10% and it is still less than 10 nm even when the concentration is 20%. The thickness of the UNCD films is 1.75, 1.80, 1.65 and 2.9 μm using H2 concentrations of 5, 10, 15 and 20%, respectively. All the films are dense and compact in the cross section, and smooth on the top surface.
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Key words:
- Ultrananocrystalline diamond film /
- Hydrogen concentration /
- Grain size
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