通过过渡层改善金刚石膜和基底间的结合性能

介绍了在金刚石膜和基底间通过施加过渡层以改善金刚石膜与基底间的结合性能的研究成果。金刚石膜可以通过过渡层沉积于多种基底上,如Ｓｉ、ＳｉＯ２ 、陶瓷（ＳｉＣ,Ａｌ２Ｏ３） 、钢及硬质合金基底等。过渡层有单层（ 如ＤＬＣ、Ｃ６０ 、Ｙ ＺｒＯ２ 、Ｃ Ｎ 膜、ＴｉＣ或ＴｉＮ） 和多层（ 如Ｍｏ／Ｎｉ、Ｍｏ／ＴｉＮ 或Ｂ／ＴｉＢ２／Ｂ 等） 之分,根据金刚石、过渡层及基底的晶格匹配性和热学匹配性,对于不同的基底应选择不同的过渡层。     

钼片上CVD金刚石膜的界面研究

借助金相显微镜，ＳＥＭ、ＥＤＸＡ对钼片上ＣＶＤ金刚石膜的界面形貌和成分进行了研究，对比了加磁场与不加磁场所沉积的金刚石膜的横民面形态特征，结果表明：加磁场与否在ＣＶＤ金刚石膜和钼基体之间均存在数μｍ厚的Ｍｏ２Ｃ中间层，它呈细小柱状昌方式生长，该层以下的钼基体发生了再结晶细化；加磁场沉积的金刚石膜较致密，（显微）空隙数量较小、金刚石颗粒尺寸较小、金刚石膜背面粘附较多的Ｍｏ２Ｃ聚集物。压痕试验法评定的     

金刚石薄膜与基材之间过渡层技术的研究

通过ＴＥＭ观察发现在金刚石膜与单晶硅片，金刚石膜与ＡｌＮ陶瓷之间存在一层过渡层，过渡层的存在为金刚石的形核及生长提供了有利的条件，受此启发，为了改善金刚民基材的结合强度，采用磁控溅射，空心离子镀，真空蒸镀等方法在Ｍｏ片上沉积ＴｉＣ，ＴｉＣＮ（Ｃ／Ｎ＝１／２）ＴｉＣＮ（Ｃ／Ｎ＝１／１０）等薄膜，研究了它们对金刚石膜与基材的结合强度的影响。     

Mo／α—Al2O3界面的二次离子质谱研究

采用电子束蒸发方法，在２００℃的抛光（１１０２）取向的蓝宝石（α－Ａｌ２Ｏ３）单晶衬底上淀积厚度为３００ｎｍ的Ｍｏ膜。经８７０℃下不同真空退火时间处理后，运用ＭＣｓ＾＋－ＳＩＭＳ技术进行了深度剖析，并结合ＸＲＤ物相分析，对Ｍｏ／Ａｌ２Ｏ３界面问题进行了探讨。结果表明，在Ｍｏ／Ａｌ２Ｏ３界面处存在原子相互扩散形成的过渡层。退火处理后，过渡层展宽，有ＭｏＯ２生成。延长退火时间，过渡层变化不大。     

爆炸喷射沉积WC-Co涂层组织及显微硬度分析

分析测试了通过爆炸喷射沉积获得的ＷＣ－Ｃｏ／Ｍ基复合材料的微观组织结构及显微硬度。试验结果表明，爆炸喷射沉积层组织形态为粗大、彼此重叠的片层状；主要组成相为ＷＣ、Ｗ、Ｃｏ及少量的Ｗ２Ｃｏ经８００℃／２ｈ热处理之后，出现了原子迁移，组织进一步均匀，并形成了新相Ｃｏ３Ｗ３Ｃ。涂层的显微硬度随处理温度升高和Ｃｏ含量增加而降低，且具有明显的各向异性。     

电沉积Co—Ni合金的原子探针场离子显微分析

用位置敏感原子探针场离子的显微镜（ＰｏＳＡＰ）、ＴＥＭ、ＳＥＭ等方法研究了电沉积工艺参数对Ｃｏ－Ｎｉ合金微观结构的影响，结果表明，低频脉冲直流电沉积的Ｃｏ－Ｎｉ合金的平均晶粒尺寸为７０ｎｍ，恒稳直流电沉积的晶粒尺寸为１００ｎｍ。Ｃｏ原子在沉积层中呈均匀分布，且Ｃｏ含量随电解中Ｃｏ离子浓度增加而显著增加。当电解液中ＣｏＳＯ４含量为１７．５ｇ／Ｌ时，沉积层由εＣｏ和αＣｏ两相组成，ＰｏＳＡＰ数据的三维     

火焰法在硬质合金上合成金刚石薄膜

用Ｏ２／Ｃ２Ｈ２燃烧火焰法在各种不同性质的衬底材料上直接合成金刚石薄膜，研究了硬质合金刀头的不同的冷却方式下，对合成金刚石膜的影响。结果表明：ＹＧ６硬质合金由于Ｃｏ的存在影响了金刚石膜的质量；当冷却方法不当时，硬质合金头刃部易过热；采和分段沉积法可改善金刚石膜与硬质合金的附着性。     

金刚石表面Cr金属化的界面扩散反应研究

利用直流磁控溅射法在金钢石颗粒表面沉积了厚度为１５０ｎｍ的金属Ｃｒ薄膜。ＳＥＭ研究表明在金刚石表面形成的Ｃｒ膜基本均匀,但有小的金属聚集体存在。俄歇深度剖析研究发现,在镀膜过程中Ｃｒ膜和金刚石基底间发生了显著的界面扩工用作用。相应的俄歇线形分析表明,沉积过程中在界面上发生化学反应形成了部分Ｃｒ２Ｃ３物种。溅射沉积功率对金刚石颗粒与金属Ｃｒ膜的界面反应有较大的影响,提高溅射功率可大大促进Ｃｒ元素的扩     

MoS2氧化表面的角度分辨X射线光电子谱研究

利用角度分辨Ｘ射线光电子谱方法研究ＭｏＳ２固体润滑材料氧化表面的化学状态，同时，用电子自旋共振法发现氧化物存在未成电子Ｍｏ＾５＋，因而氧化物存在Ｍｏ原子的三种化状态，形成了单电子的传递，转移。ＭｏＳ２的表面数分子层内的Ｍｏ原子氧化程度有差异，这种非破坏性的剖面分析方法有助于深入了解ＭｏＳ２的氧化行为。     

DMF中电沉积制备Yb-Co合金膜

研究了于室温下含有少量水的ＹｂＣｌ３－ＣｏＣｌ２－ＤＭＦ溶液中电沉积制备Ｙｂ－Ｃｏ合金膜。ＥＤＡＸ和ＸＲＤ分析表面：在０．１０ｍｏｌ／Ｌ ＹｂＣｌ３－０．１０ｍｏｌ／Ｌ ＣｏＣｌ２的ＤＭＦ电镀液中,以控制电位为－２．７５Ｖ（ＳＣＥ）进行恒电位电解,以控制电流密度为１００Ａ／ｍ＾２进行恒电流电解或以控制脉冲电流密度为１５０Ａ／ｍ＾２进行脉冲电解,可以得到不同形态和Ｙｂ含量的共沉积合金膜,且膜层光滑、     

直流热阴极CVD金刚石薄膜生长特性研究

为了获得高质量的金刚石薄膜,采用直流热阴极化学气相沉积系统分别在不同基片温度和不同碳源气体含量条件下生长金刚石薄膜,利用Raman光谱、SEM和XRD检测方法研究了基片温度和碳源气体含量对金刚石薄膜生长特性的影响.结果表明,金刚石薄膜与基片Mo之间有Mo2C的过渡层存在;1000℃的温度能够促进金刚石晶体的生长,抑制其他碳杂质的形成,CH4体积分数为2%适于快速生长高纯度的金刚石薄膜.     

Mo2C过渡层对金刚石-碳膜场发射均匀性的影响

在经过不同特殊预处理的金属钼衬底上沉积了金刚石 -碳膜 ,分别用X射线衍射谱 (XRD)、拉曼光谱 (Raman)和扫描电子显微镜 (SEM)对样品进行了分析和测试 ,并研究了样品器件的场发射特性。结果发现在金属钼衬底和金刚石 -碳膜之间形成的Mo2 C过渡层与金刚石 -碳膜场发射均匀性有着密切的联系     

Correlation between chemical vapor deposited diamond and carbon fibers substrates

Diamond film formation has been studied on carbon felts (CF) substrates produced from polyacrylonitrile precursor, at different heat treatment temperatures (HTT). Scanning electron microscopy images have revealed a polycrystalline and preferential (111) diamond film covering the whole CF surface, even for deeper planes. The average grain size increased from 3.0 up to 6.0 μm for films grown on CF treated between 1000 and 2000 °C. This behavior may be attributed to different contributions associated to the facility to extract carbons atoms from CF substrate. For CF treated at lower HTT, higher carbon atoms amount will promote higher nucleation density on diamond films and consequently a smaller grain size. Raman spectroscopy indicated good quality diamond films and the lower amount of graphitic phase was observed for diamond grown on CF obtained at 2000 °C HTT. The microstructural properties of the CF were obtained by X-ray diffraction (XRD) and show a strong dependence with HTT.     

Diamond and diamond-like carbon films

Polycrystalline diamond films are grown from low pressure gas mixtures, the deposition techniques are Microwave Plasma Chemical Vapour Deposition and Hot filament Chemical Vapour Deposition, in both techniques the deposition temperature is close to 900°C. The film growth process is strongly dominated by the initial nucleation stage, after this stage, the film grows at a rate of one micron per hour. The carbon atoms in the diamond film are fully fourfold (sp³) co-ordinated and the film properties are close to those of single crystalline diamond: extremely hard, resistant and transparent from UV to IR.Diamond-like carbon (DLC) films are amorphous and contain a variable amount of hydrogen in their structure, the carbon atoms are partially threefold (sp²) co-ordinated. Films are obtained at temperatures below 250°C and deposited on almost any substrate. Film composition, structure and functional properties are strongly dependent on the level of ionic bombardment of the film during growth. DLC films are very hard, have a low friction coefficient and good wear resistance, are chemically inert and are transparent in the IR.     

Deposition of diamond films on metal substrates

In this paper we report on the growth of polycrystalline diamond films on Mo, W, and Ni substrates using oxy-acetylene combustion flame technique. Effect of substrate temperature on the growth of diamond films has been studied in the temperature range 600–1100°C. The deposits and their surface morphology has been characterized by X-ray diffraction and scanning electron microscopy (SEM). A short duration pretreatment of Mo substrates by outer zone of the oxy-acetylene flame at lower substrate temperatures, results in the improvement of quality and adherence of the films. Growth of diamond as well as other intermediate compounds depending on the nature of substrates and interface layers is discussed. Paper presented at the poster session of MRSI AGM VI, Kharagpur, 1995     

Investigation of the nucleation mechanism in bias-enhanced diamond deposition on silicon and molybdenum

Polycrystalline diamond films were deposited on Si and Mo substrates in a microwave plasma-enhanced chemical vapour deposition reactor employing bias-enhanced nucleation. The deposition process was subdivided into two consecutive steps: the pretreatment (bias-enhanced nucleation) and the diamond growth step. To investigate the nucleation process we kept the deposition parameters during the diamond growth step constant and only changed the parameters during the pretreatment. The methods employed to analyze the deposited films after the pretreatment step were electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy.

The nucleation density (N_D) on Si following the complete deposition cycle (pretreatment and diamond growth step) increases considerably from 5 × 10⁸ cm⁻² to 5 × 10¹⁰ cm⁻² with an increase in the substrate temperature during the pretreatment (T_p) in the temperature range from 680 to 750 °C. For T_p ≥ 770 °C continuous films are formed. The structure of the pretreatment deposit undergoes likewise considerable changes: if T_p exceeds 770 °C the appearance of an intense diamond plasmon at 34 eV is observed, indicative of an increase in the concentration of diamond crystallites embedded in an otherwise amorphous carbon matrix. Our experiments suggest that diamond crystallites formed during the pretreatment serve as nucleation centres for the subsequent diamond growth.

The same deposition parameters which result in the formation of a continuous diamond film on Si, yield only low nucleation densities on Mo. An increase in N_D from 6 × 10⁶ cm⁻² to 2 × 10⁸ cm⁻² can be achieved by raising the methane concentration [CH₄] in the gas phase during the pretreatment from 5 to 50% (T_p = 820 °C). The carbon concentration at the surface for the pretreatment deposit, determined by XPS analysis, increases likewise with [CH₄]. According to the EELS analysis the structure of the pretreatment deposit is comparable with disordered graphite or a-C and no diamond plasmon is observed. The high [CH₄] is required to form the Mo-carbide interface and balance the diffusion of carbon into the metal before the a-C layer can be formed.

The formation of nucleation centres during the bias-enhanced nucleation seems under these deposition conditions to proceed via different pathways on Si and Mo. While the nucleation on Si appears to be linked to the formation of diamond nanocrystals during the pretreatment, this is not the case for Mo.     

金刚石表面的Ti、Mo、W镀层及界面反应对抗氧化性能的影响

为了提高工业金刚石的抗氧化能力,本文用XRD、SEM、DTA和TGA等方法研究了Ti、Mo、W镀层与金刚石界面反应过程、结构特征及对金刚石抗氧化性能的影响.结果表明:Ti在高于600℃、Mo在高于650℃、W在高于650℃与金刚石界面发生固相反应,通过反应扩散过程在金刚石表面外延生长成相应的TiC、MoC+Mo₂C及WC+W₂C碳化物层.该致密连续的碳化物层具有较高的抗氧化能力,延缓了金刚石表面的氧化.镀Ti、Mo、W金刚石在空气中的氧化温度达958℃、871℃和880℃.Ti、Mo、W镀层经真空碳化处理后,抗氧化温度分别达1024℃、977℃和986℃.而未镀金刚石在780℃以上即开始氧化.     

Crystallization of chemically vapor deposited molybdenum and mixed tungsten/molybdenum oxide films for electrochromic application

The paper deals with investigation of Mo oxide and mixed W/Mo oxide films showing high electrochromic performance. Films are deposited on Si and conductive glass substrates using pyrolytical decomposition at 200 °C of Mo and W hexacarbonyls in Ar/O₂ atmosphere. The study is focused on structural transformation of the films in dependence on deposition and annealing process parameters. In case of conductive glass substrate (typical for electrochromic devices), the crystallization process in Mo oxide films is almost completed at 400 °C forming triclinic MoO_2.89 and orthorhombic MoO₃ crystalline phases. The structure of mixed W/Mo oxide films is triclinic crystalline phase of tungsten oxide matrix with Mo atoms as substitutes. Discussed are, as well, differences in the crystallization process for the same films, when the substrate is Si. All the films show electrochromic effect, the mixed W/Mo oxide films expressing stronger electrochromic effect with superior color efficiency and optical modulation.     

类金刚石碳膜的制备工艺

用射频－直流等离子体化学气相沉积法制备出类金刚石膜，用多因素和单因素正交试验设计方法对类金刚石的沉积工艺进行了研究，结果表明，极板偏压、真空度和气体成分是影响膜沉积速率的主要因素。沉积速率与ＰＶ成正比，且随反应气体深度单调增加，但当Ｃ２Ｈ２浓度低于１０％时，几乎不能成膜。     

Effects of argon and oxygen addition to the CH4-H2 feed gas on diamond synthesis by microwave plasma enhanced chemical vapor deposition

In order to investigate the effects of argon and oxygen on diamond synthesis, the behaviors of diamond deposition using microwave plasma chemical vapor deposition method have been studied by varying the concentrations of argon and oxygen in the methane-hydrogen gas mixture. Diamond films were deposited on silicon wafer under the conditions of substrate temperatures: 1073 1173 K, total reaction pressure: 5333 Pa (40 Torr), methane concentrations: 0.5 5.0%, and they were characterized by scanning electron microscopy, Raman spectroscopy and optical emission spectroscopy. The deposition rates of diamond films were enhanced by adding argon into the methane-hydrogen system, but nondiamond carbon phases in the films also increased. It resulted from the increase of hydrocarbon radicals in the plasma. As oxygen was added, the quality of deposited diamond films was improved due to the decrease of C₂ radicals and increase of OH radicals in the plasma. Simultaneous addition of 0.3% oxygen and 20% argon has been able to effectively suppress the formation of nondiamond carbon components and increase the deposition rate of diamond films. It appears that the ionized argon (Ar⁺) and excited argon atoms (Ar*) may activate the various chemical species and promote the reactions between the gas phase species and oxygen in the plasma.