Thomas Evan L H, Mandal Soumen, Macdonald John Emyr, Dane Thomas G, Rawle Jonathan, Cheng Chia-Liang, Williams Oliver A
School of Physics and Astronomy, Cardiff University, Queen's Buildings, The Parade, Cardiff CF24 3AA, U.K.
Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan.
ACS Omega. 2017 Oct 16;2(10):6715-6727. doi: 10.1021/acsomega.7b00866. eCollection 2017 Oct 31.
With the retention of many of the unrivaled properties of bulk diamond but in thin-film form, nanocrystalline diamond (NCD) has applications ranging from micro-/nano-electromechanical systems to tribological coatings. However, with Young's modulus, transparency, and thermal conductivity of films all dependent on the grain size and nondiamond content, compositional and structural analysis of the initial stages of diamond growth is required to optimize growth. Spectroscopic ellipsometry (SE) has therefore been applied to the characterization of 25-75 nm thick NCD samples atop nanodiamond-seeded silicon with a clear distinction between the nucleation and bulk growth regimes discernable. The resulting presence of an interfacial carbide and peak in nondiamond carbon content upon coalescence is correlated with Raman spectroscopy, whereas the surface roughness and microstructure are in accordance with values provided by atomic force microscopy. As such, SE is demonstrated to be a powerful technique for the characterization of the initial stages of growth and hence the optimization of seeding and nucleation within films to yield high-quality NCD.
纳米晶金刚石（NCD）保留了块状金刚石的许多无与伦比的特性，但呈薄膜形式，其应用范围涵盖从微/纳机电系统到摩擦学涂层等领域。然而，由于薄膜的杨氏模量、透明度和热导率均取决于晶粒尺寸和非金刚石含量，因此需要对金刚石生长初期进行成分和结构分析，以优化生长过程。因此，光谱椭偏仪（SE）已被用于表征纳米金刚石籽晶硅上25 - 75纳米厚的NCD样品，在成核和体生长区域之间有明显的区分。由此产生的界面碳化物的存在以及合并时非金刚石碳含量的峰值与拉曼光谱相关，而表面粗糙度和微观结构则与原子力显微镜提供的值一致。因此，SE被证明是一种用于表征生长初期的强大技术，从而能够优化薄膜内的籽晶和成核过程，以获得高质量的NCD。
