热丝法化学气相沉积金刚石系统温度分布与薄膜生长关系研究

对热丝化学气相沉积金刚石薄膜系统内的三种传热方式（传导、对流和辐射）进行了比较分析,数值计算了气相空间温度分布和衬底表面二维温度分布。采用热丝化学气相沉积工艺制备了金刚石薄膜,扫描电镜结果显示金刚石薄膜在不同生长区域呈现出与温度分布相关的微观结构与形貌。     

微波CVD金刚石热沉片的制备研究

采用化学气相沉积法（CVD）制备的金刚石薄膜具有接近于天然金刚石的导热性能,是目前最为理想的热沉材料。利用微波等离子体化学气相沉积法（MPCVD）制备了金刚石热沉片,并在此基础上研究了不同沉积工艺对金刚石热沉片散热性能的影响。采用扫描电子显微镜（SEM）和激光拉曼光谱（Raman）检测了薄膜的表面形貌及纯度,金刚石热沉片的导热性能则通过测量封装LED后薄膜的散热效果来进行表征。结果表明,在其他条件不变的情况下,提高生长过程中的微波输出功率、降低反应气压以及增加基片温度有利于制备出散热性能更佳的金刚石热沉片。     

微波等离子体化学气相沉积技术制备金刚石薄膜的研究

介绍了微波等离子体化学气相沉积法（MPCVD）制备金刚石薄膜的研究情况，重点论述了该法的制备工艺对金刚石薄膜质量的影响及其制备金刚石薄膜的应用前景。     

金刚石薄膜用钢基表面过渡层研究进展

介绍了影响钢基表面金刚石薄膜沉积的不利因素,分析和综述了近10年来在提高金刚石薄膜质量以及薄膜粘结性等方面所采用的各种中间过渡层及其研究进展.过渡层可采用沉积法制备,也可采用表面改性法制备.过渡层可以制备成单层膜结构,也可制备成多层膜结构.对于不同的基底材料应选择不同的过渡层.     

微波等离子体刻蚀处理对金刚石薄膜涂层刀具附着力和切削性能的影响

用HFCVD法在硬质合金（YG6）刀具衬底上沉积金刚石薄膜,用氢微波等离子体刻蚀的方法对衬底进行表面预处理,研究了该预处理技术对WC硬质合金衬底表面成分的影响,进一步探讨了所沉积金刚石薄膜的表面形貌和附着力,并通过难加工材料实际切削试验。研究了所制备的金刚石薄膜涂层刀具的切削性能。试验结果表明,Ar-H2微波等离子体刻蚀脱碳处理是提高金刚石薄膜附着力和改善涂层刀具切削性能的有效预处理方法。     

不同等离子体体系中纳米金刚石薄膜制备的研究

利用微波等离子体化学气相沉积（MPCVD）法分别在CH4／H2／Ar体系、CH4／H2／O2体系和C2H5OH／H2体系中进行纳米金刚石（NCD）薄膜的制备研究。采用原子力显微镜（AFM）和激光拉曼光谱（Raman）等方法对不同体系中制备得到的NCD薄膜的表面形貌及其质量进行了检测。结果表明：在CH4／H2体系中添加O2对于促进高平整度NCD薄膜的效果明显优于添加At;C2H5OH／H2体系更有利于制备颗粒更细、金刚石相含量更高的NCD薄膜。利用等离子体CVD技术的相关理论对上述结论进行了理论分析。     

采用MPCVD法在硅衬底上选择性生长金刚石膜

采用微波等离子体化学气相沉积（MPCVD）法在附有SiO2掩摸的硅衬底上选择性沉积出了金刚石膜。采用扫描电子显微镜（SEM）和Raman光谱仪对金刚石膜的表面形貌和结构进行了表征。并讨论了衬底温度对金刚石薄膜选择性沉积的影响。得出了较佳的沉积条件。     

热丝CVD金刚石薄膜制备及碳纳米管形核作用的研究

利用热丝化学气相沉积法（HF－CVD）进行了金刚石薄膜制备和碳纳米管形核作用的研究。获得了制备金刚石薄膜的优化工艺参数。利用碳纳米管作为形核前驱获得了高质量的金刚石薄膜，其沉积速率可达2．5μm/h，晶粒生长完善，而且没有出现聚晶现象。研究了碳纳米管涂料质量对薄膜沉积特性的影响，并对其机理进行了初步探讨。     

SiNx介质薄膜制备及其对GaN表面金刚石形核生长的影响

SiNx作为GaN和金刚石异质结构的中间层，不仅是下层GaN材料的保护层，也是上层金刚石的形核生长层，因此SiNx介质薄膜对于GaN表面合成高质量金刚石具有重要的意义。研究分别采用低压化学气相沉积（LPCVD）和磁控溅射（MS）方法在GaN-Si衬底上制备SiNx介质薄膜。利用扫描电镜、傅立叶红光光谱、X射线衍射、激光拉曼等技术对SiNx薄膜的表面形貌、晶体结构和表面官能团等进行分析。结果表明，采用LPCVD镀制的非晶态SiNx介质薄膜经籽晶播种、形核生长金刚石后，金刚石/SiNx/GaN界面完整致密；采用MS制备的SiNx介质薄膜呈晶态特征，对应的界面出现明显的刻蚀坑。沉积方式会影响SiNx薄膜的晶体结构和微观形貌，高致密度的非晶态结构有利于金刚石层快速形核生长，对于构建金刚石基GaN结构更为有利。     

WC—Co硬质合金表面不同去钴预处理方法的比较研究

用微波等离子体化学气相沉积（MWPCVD）制备金刚石薄膜涂层之前，采用盐酸、硝酸化学腐蚀和氢-氧等离子体对WC-Co硬质合金（YG6）基体表面进行去钴预处理。扫描电子显微镜形貌观察和X射线衍射谱分析都表明，与化学腐蚀方法相比，氢-氧等离子体处理具有独特的表面钴效果，沉积金刚石薄膜的喇曼谱分析更证实其对涂层质量的改善，且对MWPCVD过程而言有其技术上的一些优越性。     

甲烷浓度对金刚石薄膜质量的影响

纳米金刚石薄膜具有优异的性能,已在多个领域获得广泛应用.但微波等离子体化学气相沉积制备的金刚石薄膜质量却严重受沉积工艺的影响,为了深入了解沉积工艺对制备的金刚石薄膜质量的影响,本文详细研究了甲烷浓度对微波等离子体化学气相沉积( MPCVD)金刚石薄膜质量的影响,利用扫描电镜、X射线衍射、拉曼光谱以及原子力显微镜对其进行...     

分体圆柱谐振腔法用于金刚石膜微波介电性能测试的研究

针对金刚石膜微波介电损耗低、厚度薄带来的微波介电性能测试难点, 研制了一台分体圆柱谐振腔式微波介电性能测试装置。利用不同直径的蓝宝石单晶样品, 用上述装置对低损耗薄膜类样品微波介电性能的测试能力及样品直径对测试结果的影响进行了实验研究。在此基础上, 使用分体圆柱谐振腔式微波介电性能测试装置对微波等离子体化学气相沉积法和直流电弧等离子体喷射法制备的高品质金刚石膜在Ka波段的微波介电性能进行了测试比较。测试结果表明, 由Raman光谱、紫外-可见光谱等分析证明品质较优的微波等离子体化学气相沉积法制备的金刚石膜具有更高的微波介电性能, 其相对介电常数和微波介电损耗值均低于直流电弧等离子体喷射法制备的金刚石膜。     

氧化铝基体表面预处理对金刚石薄膜生长的影响

采用微波等离子体化学气相沉积方法,在经不同预处理的氧化铝衬底上沉积金刚石薄膜.用X射线衍射仪、激光拉曼光谱仪、扫描电镜(SEM)对所得薄膜的成分、物相纯度和表面形貌进行表征,比较不同的预处理方式对金刚石薄膜生长的影响.结果表明,基体表面经过熔融碱腐蚀后形成薄膜的膜基结合良好且膜材质量最佳,但表面平整度较低;而基体只经金刚石微粉乙醇悬浊液超声处理则在沉积时金刚石容易成膜,且结构要更为致密;在经过酸腐蚀的基体上沉积金刚石薄膜时,容易在薄膜与基体之间先形成过渡层,而后才进行金刚石薄膜的沉积.所得结果表明熔融碱腐蚀处理是获得电学应用氧化铝基金刚石薄膜复合材料的最适宜的基体表面预处理.     

Characterisation of CVD diamond detectors used for fast neutron flux monitoring

Natural diamond detectors (NDD) have been successfully used for fast neutron spectrometry on various fusion installations in plasma diagnostics. These detectors can work at high temperature, are radiation hard and exhibit a high energy resolution. However, the use of NDD is limited by the availability of IIa type diamonds exhibiting high electronic properties. With the recent advance in the growth of high quality chemically vapour deposited (CVD) diamond at LETI, CVD diamond appears to be a very promising material for plasma diagnostics. We present here for the first time results of the use of CVD diamond detectors for fast neutron flux monitoring on a neutron generator. The characteristics of CVD diamond detectors are compared with that of high quality NDD made by TRINITI. Pulse height spectra have been measured with CVD detectors and NDD under both 5.5 MeV alpha particles and 14.1 MeV neutrons. The quality of CVD diamond enables the recording of structured spectra allowing the distinction between the different neutron reactions on carbon. The efficiency of CVD diamond monitors and their actual limitations are analysed and discussed.     

Analysis of surface preparation treatments for coating tungsten carbide substrates with diamond thin films

The effect of various substrate surface treatments on (i) the pre-growth topography and composition of the treated substrate, and (ii) the quality of diamond thin films produced by hot-filament chemical vapour deposition on tungsten carbide substrates, is reported. Two different substrate grain sizes were subjected to various surface treatments. They were then examined for surface material composition and topography using scanning electron microscopy and X-ray diffraction (XRD). Subsequently, diamond films were deposited on the samples and their quality analysed by Raman spectroscopy and XRD techniques. These analyses do not indicate a strong dependence between the substrate grain size and film quality. However, the surface-treatment method affects the resulting substrate surface topography and film quality. This revised version was published online in November 2006 with corrections to the Cover Date.     

非晶金刚石薄膜的拉曼光谱研究

碳离子的能量是影响非晶金刚石薄膜结构和性质最关键的工艺参数．采用磁过滤真空溅射离子技术,研究不同衬底偏压Ｖ_ｂ（即不同碳离子能量）下制备的非晶金刚石薄膜的拉曼光谱和表面形貌．结果表明：－５０Ｖ≤Ｖ_ｂ≤－１０Ｖ时,样品表面均匀、光滑,拉曼谱是对称且很宽的散射带;Ｖ_ｂ＞－１０Ｖ或Ｖ_ｂ＜－５０Ｖ时,已有晶团出现,表面粗糙度明显增加,拉曼谱明显地分裂为１５８０ｃｍ^－１的Ｇ带和１３５０ｃｍ^－１的Ｄ带．     

Effects of the grain size of CVD diamond films on the detector performance

Although the unique properties of CVD diamond films have made it a candidate material for radiation detectors, the detector performance is strongly dependent on the film quality. In this paper, three CVD diamond films with different grain size were grown by using a hot-filament chemical vapor deposition (HFCVD) technique and the ratio of the grain size to the film thickness is high to 50%. 5.9 keV ⁵⁵Fe X-rays measured the photocurrents and the pulse height distributions (PHDs) of these CVD diamond detectors. The detector performance is improved with the grain size increasing. The dark-current of 16.0 nA and the photocurrent of 15.9 nA are obtained at an electrical field of 50 kV⋅cm⁻¹ and the PHD peak is well separated from the noise pedestal.     

Effect of B/C ratio on the physical properties of highly boron-doped diamond films

Highly boron-doped diamond films were deposited on silicon substrate by hot filament chemical vapor deposition in a gas mixture of hydrogen and methane. The chemical bonding states, surface texture, and electrical resistivity of these films were analyzed by X-ray photoelectron spectroscopy, scan electron microscope, and four-point probe method. It was found that boron dopants play an important role in the texture and chemical bonding states of the diamond films. An appropriate concentration of boron dopants (B/C ratio of 10 000 ppm) can simultaneously improve crystal quality and reduce resistivity of the diamond films. The minimum resistivity of diamond films reaches 1.12 × 10⁻² Ω cm, which is applicable as electrodes.