激光辅助EACVD低温生长纳米金刚石薄膜

近年来，利用高温CVD技术淀积大面积、高质量金刚石薄膜的研究已取得了突破性成果。但随着金刚石薄膜在光学、医学、光电子学等领域的应用，低温合成纳米金刚石薄膜已成为目前国内外研究的重点课题。纳米材料本身的优越性及金刚石薄膜所具有的优异物理化学性质，将使纳米金刚石薄膜具有广阔的应用前景。故低温合成纳米金刚石薄膜的研究具有重要的实际意义。本工作采用激光辅助技术，利用非聚焦的准分子激光束激活硅（Si）基片表面粒子，激光能量为70～180mJ，激光脉宽为20us。反应气体为CH4 H2，所用基片为Si（100）单晶片。在基片温度…     

循环刻蚀工艺对金刚石膜形貌和电阻率的影响

为了制备新型金刚石薄膜辐射剂量计,针对目前金刚石薄膜质量较差,难于满足辐射剂量计要求的问题,采用微波等离子体CVD法,研究了循环刻蚀生长阶段工艺参数(甲烷浓度,基片温度)和刻蚀方法对薄膜形貌、电阻率的影响。结果表明,循环刻蚀生长有利于提高金刚石薄膜的纯度和取向性。当?(甲烷)为0.34%,基片温度为960℃时,可获得[100]晶面取向的、电阻率达1011Ω·cm的金刚石膜,和采用常规工艺所得金刚石薄膜相比,其电阻率提高了3个数量级。     

声表面波器件基片金刚石薄膜厚度的测量

研究了声表面波器件(SAWD)基片金刚石膜的厚度测量方法。通过光切显微镜和扫描电镜(SEM)测量结果的比较，讨论了测量精度。在沉积制备多层薄膜SAWD基片中金刚石薄膜的实验过程中，选用光切显微镜测量膜厚，测量精度0．5～1．0μm。     

基片表面预处理对热丝CVD法生长金钢石薄膜的影响

本文研究了在热丝CVD方法生长金刚石薄膜中,基片表面的研磨处理对金刚石成核密度以及生长膜结构的影响。发现基片表面的预处理一方面可以提高金刚石的成核密度,另一方面又使生长膜的结构变得不利于应用。最后讨论了基片表面预处理对金刚石成核作用的机理和两种新的表面预处理方法。     

金刚石/硅复合膜的导热特性研究

用金刚石粉,用不同时间在两片镜面抛光的(111)硅基片上分别打磨.两片硅基片打磨后都仍保持镜面特征.采用微波等离子体化学气相沉积系统,利用氢气、甲烷和氧气为前驱气体,在同样参数条件下,在基片上制备了直径5 cm的金刚石薄膜.用扫描电镜和X射线衍射分析两片薄膜结构.分析结果表明其表面形貌基本相同都为(111)择优取向的金刚石薄膜;但X射线衍射分析表明打磨时间较长的薄膜中含有一定量在非晶成分.用热导测试仪测试两薄膜和硅基片的热导率约为:241.7 W/mK,192.9 W/mK和169.3 W/mK.结合扫描电镜和X射线衍射分析结果我们讨论了基底处理对金刚石/硅复合膜的导热特性的影响.     

基片预处理工艺对CVD金刚石成核行为的影响

本文采用微波等离子体辅助化学气相沉积工艺,对不同预处理的(100)单晶硅基片上金刚石的成核行为进行了初步研究,并利用定量金相及扫描电子显微镜分析了金刚石的成核速率及晶体特征。由此提出了用0.1μm超细金刚石粉对基片的研磨工艺。该工艺可有效提高金刚石成核率,从而有助于获得晶粒细小均匀,表面粗糙度低的金刚石薄膜。采用C60涂复并结合研磨工艺,使成核率获得了进一步提高。     

激光辅助化学气相沉积金刚石薄膜实验研究

本文采用激光辅助化学气相沉积法合成了厚度为１５μｍ的金刚石薄膜。实验结果表明，以丙酮为碳源气体，并用ＸｅＣｌ（３０８ｎｍ）准分子解离，Ｈ２秀灯线进行予先解离，当选择和中种实验参数，可获得高质量的金刚石薄膜。本文这讨论了衬底温度以及灯线温度等实验参数对薄膜生长速率与薄膜质量的影响。     

硫掺杂纳米金刚石薄膜的图形化生长

利用电子增强热丝化学气相沉积(EACVD)技术,以CH4/H2/H2S/Ar为工作气体,SiO2/Si为衬底,制备了硫掺杂金刚石薄膜。研究了利用光刻技术实现薄膜的图形化生长。结果表明:以SiO2作掩模的光刻技术能够使得硫掺杂金刚石薄膜在光滑SiO2/Si基片上很好地图形化生长。Hall效应检测表明硫掺杂金刚石薄膜为n型,给出了n型金刚石/p-Si异质结的反向I-V特性曲线。     

硅表面缺陷对金刚石成核结膜的重要作用

本文采用研磨、超声波和化学方法处理单晶硅基片,观察了缺陷形成的形态,进行低压法合成金刚石多晶薄膜的实验研究,初步讨论了缺陷在金刚石成核结膜中的重要作用。     

类金刚石薄膜的结构和红外光学性能研究

本文用辉光放电等离子体化学气相沉积(PCVD)法在Si、Ge玻璃等基片上制备出品质较好的类金刚石薄膜。首先,用拉曼光谱和红外吸收谱研究了所制备薄膜的结构,并且研究了制备膜的光吸收和光学带隙,然后,研究了沉积有类金刚石膜Si,Ge等基片的红外透过率。     

Selective deposition of diamond films

Polycrystalline diamond films have been selectively deposited on a silicon surface. A novel process was developed which exposes a patterned, scratch damaged silicon area, surrounded by SiO₂, to a high pressure microwave plasma of hydrogen containing methane. The hydrogen plasma dissociates the methane injected into the reaction chamber, resulting in diamond deposition, which occurs only on the exposed silicon. Under the process conditions described in this work, some in situ plasma etching of the oxide is observed, resulting in little or no growth of diamond in unwanted areas, and further enhancing the selectivity. A variety of patterns and structures have been fabricated. Raman spectroscopy confirmed the films were diamond.     

Diamond icosahedron on a TiN-coated steel substrate

Diamond layers have been deposited by hot filament chemical vapour deposition (HF CVD) on TiN-coated steel substrates. After deposition, we could observe separate, well-developed diamond icosahedrons and decahedrons on the surface. We have found that a lower content of methane in hydrogen supports their growth, this being a result of multifold twinning. The quality of diamond layers has been evaluated by Raman spectroscopy and scanning electron microscopy.     

微米金刚石聚晶薄膜场发射点的研究

采用微波等离子化学气相沉积方法,以甲烷和氢气为反应气体,在镀有金属钛的陶瓷衬底上,制备了微米金刚石聚晶薄膜.利用扫描电镜、拉曼光谱、X射线光电子能谱对薄膜的化学组成、微观结构和表面形貌进行了表征.用二级结构的场发射仪和扫描隧道显微镜研究了薄膜的场发射性能,结果表明微米金刚石聚晶薄膜发射点主要来源于聚晶颗粒.进一步研究了单个聚晶颗粒表面不同区域的发射性能,发现多种因素对场发射的性能有影响.     

加速器法沉积无氢类金刚石薄膜的性能与结构

本文对用加速器法（ＣＡＤ）在９Ｃｒ１８不锈轴承钢上制备的无氢类金刚石（ＨＦＤＬＣ）样品进行了显微硬度测试、磨擦磨损试验、激光扫描显微镜（ＬＳＭ）观察和透射电镜（ＴＥＭ）分析。试验结果表明用该工艺方法制 的ＨＦＤＬＣ膜具有非晶态显微结构，硬度极高，磨擦贪婪在损性能优异。     

衬底位置对大面积CVD金刚石薄膜质量的影响

采用石英钟罩式微波等离子体化学气相沉积(MWPCVD)设备制备了大面积金刚石薄膜,结合X射线衍射谱(XRD)、扫描电子显微镜(SEM)和激光喇曼(Raman)谱等实验手段,较系统地研究了衬底位置对金刚石薄膜质量的影响规律.结果表明,在等离子体球内部的空间范围内,距等离子体球中心垂直距离越远衬底上所沉积的金刚石薄膜质量越好;通过调整衬底位置,可明显改善其上不同区域所沉积的金刚石薄膜质量,最后在等离子体球边缘附近可沉积出晶粒均匀一致几乎不舍非晶碳的大面积高质量金刚石薄膜.此研究为进一步改善大面积金刚石薄膜均匀性和薄膜质量提供了一种实用的途径.     

喷射CVD法制备金刚石厚膜及其内应力分析

采用直流电弧等离子体喷射CVD法制备出金刚石薄膜,利用扫描电子显微镜(SEM)、Raman光谱及X射线衍射(XRD)等研究基底温度对金刚石厚膜生长特性及内应力的影响。结果表明:950℃基底温度生长的金刚石厚膜结晶性能较好,纯度较高;而850℃和1050℃生长的金刚石厚膜表面呈现大量的孪晶缺陷,结晶度较低,同时出现较多的非金刚石碳,纯度较低。随着基底温度的增加,(111)晶面和(311)晶面的衍射峰强度逐渐增强,(220)晶面的衍射峰强度逐渐降低。850℃和950℃基底温度生长的金刚石厚膜的宏观应力和微观应力都呈现出拉应力,1050℃基底温度生长的金刚石厚膜的宏观应力和微观应力都呈现出压应力。     

Effects of nitrogen trifluoride on the growth and properties of plasma-enhanced chemical-vapor-deposited diamond-like carbon films

The effects of nitrogen trifluoride (NF₃) on the growth and properties of plasma-enhanced chemical-vapor-deposited diamond-like carbon (DLC) films were investigated. The addition of NF₃ increases the deposition rate of DLC film due presumably to the removal of activated hydrogen species by the fluorine radical (F⁻). Diamond-like carbon films deposited in a methane/NF₃ mixture have a higher refractive index, a lower bulk resistivity, and a lower optical bandgap compared to films deposited in pure methane due to a lower hydrogen content in the films. Moreover, the bulk resistivity of methane/NF₃ DLC films remains constant for annealing temperatures below 400°C. Thus, DLC films deposited with NF₃ are more stable than DLC films deposited without NF₃.     

Growth of diamond films on si(100) with and without boron nitride buffer layer

Diamond films were grown on Si(100) and boron nitride deposited Si(100) substrates using hot filament chemical vapor deposition (HFCVD) technique. Microstructure and morphology of diamond films have been investigated systematically as a function of CH₄ and H₂ ratio and the ambient pressure. The deposited films were characterized by employing techniques such as scanning electron microscopy (SEM) and laser Raman spectroscopy. The average size and growth rate of diamond particles were found to increase with the CH₄ to H₂ ratio and decrease with the ambient pressure. Maximum growth rate of synthetic diamond deposited on Si(100) was found to be ∼3.5 µm/hr for the film deposited at 20 Torr with CH₄:H₂ ∼ 1.5:100 (substrate temperature ∼850°C). In most of these depositions, the morphology of the diamond crystals was cubic with significant secondary nucleation at higher methane concentrations and ambient pressure. The diamond film deposited on Si(100) with BN buffer layer shows an improvement in growth rate and the coverage, and the secondary nucleation was found to be substantially reduced, resulting in relatively smooth morphology. MicroRaman investigations show less amorphous graphite formation and better structural quality of diamond film than the one deposited without the BN buffer layer. On leave from Department of Physics University of Poona, Pune-411007 INDIA     

Dependence of surface morphology of CVD diamond films on deposition conditions

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