CVD金刚石成核的最新研究

研究了化学气相条件下金刚石在非均匀研磨硅基底表面及镜面基底和均匀研磨基底边缘及角域处的成核行为。发现ＣＶＤ金刚石成核不仅依赖于沉积区缺陷，更主要由缺陷的锐度决定，即缺陷加强ＣＶＤ金刚石成核的锐度效应。在对无序碳上ＣＶＤ金刚石成核研究的基础上，讨论了ＣＶＤ金刚石成核的机理，并由此阐明了各种表面预处理及负偏压等增强ＣＶＤ金刚石成核的微观过程。     

硬质合金YG8上金刚石薄膜的成核研究

利用调节基底表面碳流量的方法促进了热丝ＣＶＤ中硬质合金ＹＧ８上金刚石薄膜的成核，使成核期大为缩短，根据扫描电镜和拉曼光谱对沉积结果的分析，研究了ＹＧ８上金刚石薄膜成核的机理。     

硬质合金YG8上金刚石薄膜的成核研究

利用调节基底表面碳流量的方法促进了丝ＣＶＤ中硬质合金ＹＧ８上金刚石薄膜的成核，使成核期大为缩短，根据扫描电镜和拉曼光谱对沉积结果的分析，研究了ＹＧ８上金刚石薄膜成核的机理。     

MPCVD法在氧化铝陶瓷上的金刚石膜沉积及其成核分析

用微波等离子体化学气相沉积（ＭＰＣＶＤ）法在氧化铝陶瓷基片上沉积了金刚石薄膜。实验表明，对基片进行适当的预处理，包括用金刚石研磨膏仔细研磨和沉积前原位沉积一层无定形碳层，可显著提高成核密度；对硅衬底和氧化铝基片上金刚石膜的成核过程进行了对比分析，并提出了提高氧化铝基片上沉积金刚石的成核的措施。     

预沉积无序碳对CVD金刚石成膜的增强作用

研究了热丝ＣＶＤ系统中预沉积无定形碳对金属石成核的促进作用，分析了金 不管不顾民核的特征和机理，探索了无定形碳上金刚石成核的条件，并由此实现了ＹＧ８硬质合金上金刚石的成核和生长。     

原位光发射谱研究横向偏压金刚石薄膜生长过程

利用热丝ＣＶＤ方法研究了横向偏压对金刚石薄膜成核和生长的影响．实验表明,随着偏流的增加,金刚石在光滑硅衬底上的成核密度得到显著提高,最高可达 １．１×１０^８ｃｍ^－２,但是横向偏压不利于金刚石薄膜的生长．原位光发射谱研究发现,横向偏流的增加提高了原子氢和ＣＨ基团的浓度,导致衬底表面非晶碳层的形成,这可能是造成横向偏压促进金刚石成核却不利于金刚石薄膜生长的主要原因．     

CVD生长金刚石薄膜衬底负偏压增强成核效应

基于已经得到的实验结果的分析，本文较详细地讨论了低压化学气相沉积（ＣＶＤ）金刚石薄膜过程中，衬底负偏压对金刚石成核的增强效应，明确阐述了负偏压增强成核的作用机理，并且讨论了这种效应作为提高金刚石在非金刚石衬底表面成核密度的一种方法所具有的优点以及存在的不足。     

正偏压控制CVD金刚石薄膜成核的理论研究

本文从理论上研究了等离子体ＣＶＤ金刚石薄膜过程中的衬底正偏压增强金刚石成核效应，给出了增强成核强度与正偏压和沉积参数的关系，理论较好地描述了实验现象。     

Al2O3陶瓷上沉积金刚石薄膜的研究

以酒精为碳源，用热丝ＣＶＤ法对不同表面状态的Ａｌ２Ｏ３衬底进行了金刚石薄膜沉积的比较，用扫描电镜，喇曼光谱和Ｘ射线衍射等方法检测了沉积出的金刚石膜的质量，并讨论了它们对成核和生长的影响。     

CVD金刚石薄膜的成核机理研究

利用热丝化学气相沉积 ,在预沉积无定形碳的硅镜面基底及表面研磨预处理的铜基底上 ,实现了金刚石薄膜的沉积 ,并由此讨论了金刚石的成核机理。研究表明 ,无定形碳是金刚石成核的前驱态 ;成核密度不仅与基底材料有关 ,更主要由基底的表面状态决定 ,基底表面状态的设计是改善成核密度的最有效的方法。     

Nucleation behaviour of diamond particles on silicon substrates in a hot-filament chemical vapour deposition

Diamond films and particles have been deposited on a silicon substrate using a hot-filament chemical vapour deposition (CVD) method in order to study the effect of hydrogen on the behaviour of diamond nucleation. The nucleation density of diamond was affected by both hydrogen treatment prior to deposition and filament temperature,T _f. The nucleation density was decreased markedly with increasing hydrogen-treatment time. The nucleation density also changed with increasingT _f, which increased initially and then reached a maximum at 2100°C and decreased thereafter. Etching of the substrate surface was observed and enhanced with both increasing hydrogen-treatment time and increasingT _f. The changes in nucleation behaviour were related closely to the etching of substrate surface. These results are explained in terms of the etching of nucleation sites.     

CVD金刚石的形核和生长

应用自制的热解丝CVD装置,研究了在金刚石沉积过程中改变甲烷浓度对其形核和生长的影响。结果表明,金刚石形核后,增加甲烷浓度,仍然可以在硅基底表面继续形成新的晶核。但是甲烷浓度由0．6％逐渐增加到1．2％时,所得最终形核密度比一开始就将甲烷浓度设为1．2％的形核密度低。新晶核比先形成的晶核具有较大的长大速度,随后所有晶核尺寸逐渐趋向相同。     

HF CVD diamond nucleation and growth on polycrystalline copper: A kinetic study

This paper reports on the kinetics of diamond nucleation and growth on polycrystalline copper investigated by in situ Auger Electron Spectroscopy and Scanning Electron Microscopy. Copper is a reference substrate to study the diamond nucleation from graphite. The substrate is first treated with diamond paste. However the diamond seeds let on the surface by the pre-treatment are almost completely transformed into graphite. The nucleation of CVD diamond can be well described in the framework of carbon phase transformations. Diamond seeds deposited on the substrate are first transformed into graphitic layers. A process occurring on the edges site of graphite is subsequently postulated, in agreement with the Lambrecht model.     

Raman spectroscopy characterization of diamond films on steel substrates with titanium carbide arc-plated interlayer

Diamond chemical vapour deposition (CVD) on steel represents a difficult task. The major problem is represented by large diffusion of carbon into steel at CVD temperatures. This leads to very low diamond nucleation and degradation of steel microstructure and properties. Recent work [R. Polini, F. Pighetti Mantini, M. Braic, M. Amar, W. Ahmed, H. Taylor, Thin Solid Films 494 (2006) 116] demonstrated that well-adherent diamond films can be grown on high-speed steels by using a TiC interlayer deposited by the PVD-arc technique. The resulting multilayer (TiC/diamond) coating had a rough surface morphology due to the presence of droplets formed at the substrate surface during the reactive evaporation of TiC. In this work, we first present an extensive Raman investigation of 2 μm, 4 μm and 6 μm thick diamond films deposited by hot filament CVD on TiC interlayers obtained by the PVD-arc technique. The stress state of the diamond was dependent on both the films thickness and the spatial position of the coating on the substrate. In fact, on the top of TiC droplets, the stress state of the diamond was much lower than that of diamond in flatter substrate areas. These results showed that diamond films deposited on rough TiC interlayers exhibited a wide distribution of stress values and that very large compressive stress exists in the diamond film grown on flat regions of steel substrates with a TiC interlayer. Diamond films could accommodate stresses as large as 10 GPa without delamination.     

化学气相沉积金刚石薄膜生长的原位反射率测量

报道了化学气相沉积金刚石薄膜生长的原位反射率测量,提出了监控金刚石薄膜生长的激光反射多光束干涉的数学模型。通过原位反射率的测量,精确监控了金刚石薄膜的生长厚度,成功地制备了红外增透增,这种方法的测量装置简单、紧凑而且可靠。     

电化学法预处理硅基片提高金刚石成核密度的研究

通过用电化学法预先沉积一层碳膜的方法，利用热丝化学汽相沉积法使金刚石在光滑硅片上的成核密度达到１０７ｃｍ－２左右，与未镀碳膜相比提高了近３个数量级。文中还分析了可能的原因。     

High velocity SAW using aluminum nitride film on unpolished nucleation side of free-standing CVD diamond

High performances surface acoustic wave (SAW) filters based on aluminium nitride (AlN)/diamond layered structure have been fabricated. The C-axis oriented aluminum nitride films with various thicknesses were sputtered on unpolished nucleation side of free-standing polycrystalline chemical vapor deposition (CVD) diamond obtained by silicon substrate etching. Experimental results show that high order modes as well as Rayleigh waves are excited. Experimental results are in good agreement with the theoretical dispersion curves determined by software simulation with Green's function formalism. We demonstrate that high phase velocity first mode wave (so-called Sezawa wave) with high electromechanical coupling coefficient are obtained on AlN/diamond structure. This structure also has a low temperature coefficient of frequency (TCF), and preliminary results suggest that a zero TCF could be expected.     

CATALYST EFFECT FOR DIAMOND NUCLEATION IN THE LOW PRESSURE PROCESS

The fundamental study of diamond nucleation on several kinds of substrates using the hot-filament CVD method, was carried out. To investigate the diamond nucleation density, the substrate which coated with the catalytic materials by the vacuum deposition was utilized. Diamond particles scarcely grew on a normal Si wafer, but a catalytic material promoted the growth of diamond on the Si substrate. The catalytic material increases the diamond nucleation density as compared with any other substrates with a surface treatment. The particles grown on the substrates have been examined by means of x-ray diffraction and scanning electron microscopy, and identified as diamond.