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。     

热丝法沉积金刚石膜工艺参数优化的微观机理与预测

弄清化学气相沉积金刚石膜的机理对优化工艺参数具有指导意义。在前期工作中，作者辨析了氢原子、甲基和乙炔在金刚石膜沉积中的作用。本文建立了两个微观指标，即甲基浓度和氢原子与乙炔浓度的比值，分别对应生长金刚石和刻蚀非金刚石碳。通过对G-H和G-H-O反应气氛的模拟，讨论了这两个指标与灯丝温度、气源组成和气压的关系，并构建了含氧气氛生长金刚石的G-H-O三元相图。对热丝法沉积金刚石膜的工艺参数的优化选择进行了机理分析与预测。为工业化生产金刚石膜提供了参考。     

热丝化学气相沉积纳米金刚石修复损伤PCD刀具的研究

利用热丝化学气相沉积装置, 以聚晶金刚石片为衬底, 在氢气/丙酮/氩气反应体系中研究了衬底温度对纳米金刚石生长的影响。采用扫描电子显微镜对生长结果进行了表征, 结果表明在衬底温度950℃的情况下, 金刚石薄膜表面结构呈\     

化学气相沉积金刚石膜

详细讨论了金刚石膜的化学气相沉积方法、特性及生长机理。指出了今后的研究重点。     

温度场对热丝化学气相沉积大面积生长金刚石膜的影响

用１００×１００ｍｍ大面积加热器进行了气相生长金刚石膜试验，对得到的金刚石膜样品作了拉曼光谱分析，并用扫描电镜观察了不同空间区域中金刚石形核的特点．拉曼光谱和扫描电镜观察的结果，均给出了与温度分布特点较好的对应．本研究的结果，指出厂热丝法大面积气相生长金刚石膜工业应用的可能性．     

热丝法沉积金刚石膜工艺参数优的微观机理与预测

弄清化学气相沉积金刚石膜的机理对优化工艺参数具有指导意义.在前期工作中,作者辨析了氢原子、甲基和乙炔在金刚石膜沉积中的作用.本文建立了两个微观指标,即甲基浓度和氢原子与乙炔浓度的比值,分别对应生长金刚石和刻蚀非金刚石碳.通过对C-H和C-H-O反应气氛的模拟,讨论了这两个指标与灯丝温度、气源组成和气压的关系,并构建了含氧气氛生长金刚石的C-H-O三元相图.对热丝法沉积金刚石膜的工艺参数的优化选择进行了机理分析与预测,为工业化生产金刚石膜提供了参考.     

热丝化学气相沉积纳米金刚石修复损伤PCD刀具的研究北大核心CSCD

利用热丝化学气相沉积装置,以聚晶金刚石片为衬底,在氢气/丙酮/氩气反应体系中研究了衬底温度对纳米金刚石生长的影响。采用扫描电子显微镜对生长结果进行了表征,结果表明在衬底温度950℃的情况下,金刚石薄膜表面结构呈"菜花"状,致密性较差,生长速率为4.44μm/h。随着温度当衬底温度的降低,"菜花"状结构逐渐消失,致密性提高,生长速率降低。当衬底温度下降到750℃时,"菜花"状结构完全消失,生长速率为3.43μm/h。根据实验结果对损伤长度从几微米到几十微米的聚晶金刚石铣刀刃口进行了修复,并采用扫描电子显微镜进行了表征,结果显示修复后表面光洁度有明显改善。对钛合金片表现为良好的加工效果。     

在硬质合金上化学气相沉积金刚石膜

含碳化物的硬质合金材料,是一种有用的刀具和耐磨材料。用热灯丝化学气相沉积的方法,在其上沉积金刚石薄膜,可进一步提高其耐磨性、切削性和使用寿命。采用了不同的表面预处理方法和沉积参数,在硬质合金底材上沉积出了均匀的金刚石薄膜。初步检验证明其样品有很高的硬度和附着力。     

热丝法化学气相沉积金刚石膜

用热丝法沉积金刚石膜,分离送入氢气和甲烷,可以减少钨丝碳化,提高功率利用率.分送与混送相结合,可以制备晶体形态良好的金刚石膜.到达基材表面的活性粒子的数量是提高金刚石膜生长速率的关键.生长速率可达3.8μm/h,均匀区面积达400mm2.     

热丝CVD大面积金刚石薄膜的生长动力学研究

在传统工业型热丝化学气相沉积（HFCVD）反应腔内，相关工艺参数取模拟计算优化值的条件下，采用XRD，SEM及Raman光谱等分析手段研究了单晶Si（100）上较大面积金刚石薄膜的动力学生长行为，讨论了晶格取向的变化规律。结果表明：优化工艺参数条件下，在模拟计算的衬底温度和气体温度分布均匀的区域内，沉积的金刚石薄膜虽存在一定的内应力，但整体薄膜连续、均匀，几何晶形良好，质量较高，生长速率达1．8μm／h。薄膜生长过程中晶形显露面受衬底温度和活性生长基团浓度的影响较大。     

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.     

Deposition and characterization of smooth ultra-nanocrystalline diamond film in CH4/H2/Ar by microwave plasma chemical vapor deposition

The smooth ultra-nanocrystalline diamond (UNCD) films were prepared by microwave plasma chemical vapor deposition (MWCVD) using argon-rich CH₄/H₂/Ar plasmas with varying argon concentration from 96% to 98% and negative bias voltage from 0 to −150 V. The influences of argon concentration and negative bias voltage on the microstructure, morphology and phase composition of the deposited UNCD films are investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), atom force microscopy (AFM), and visible and UV Raman spectroscopy. It was found that the introduction of argon in the plasma caused the grain size and surface roughness decrease. The RMS surface roughness of 9.6 nm (10 micron square area) and grain size of about 5.7 nm of smooth UNCD films were achieved on Si(100) substrate. Detailed experimental results and mechanisms for UNCD film deposition in argon-based plasma are discussed. The deposited highly smooth UNCD film is also expected to be applicable in medical implants, surface acoustic wave (SAW) devices and micro-electromechanical systems (MEMS).     

微波等离子体化学气相沉积法在硅片上同时生长碳化硅和金刚石

研究了衬底温度、核化密度、衬底表而预处理等工艺参数对微波等离子体化学气相沉积法在硅片上同时生长碳化硅和金刚石的影响.采用扫描电镜、X-射线衍射、喇曼光谱和红外光谱对样品进行了表征.结果表明:从高核化密度生长的金刚石膜中探测不到碳化硅;不论对硅衬底进行抛光预处理还是未抛光预处理,从低核化密度牛长的金刚石厚膜中总能探测到碳化硅.碳化硅生长在硅衬底上未被金刚石覆盖的地方,或者是在金刚石晶核之间的空洞处.碳化硅形成和金刚石生长是同时发生的两个竞争过程.此研究结果为制备金刚石和碳化砟复合材料提供了一种新的方法.     

The versatility of hot-filament activated chemical vapor deposition

In the field of activated chemical vapor deposition (CVD) of polycrystalline diamond films, hot-filament activation (HF-CVD) is widely used for applications where large deposition areas are needed or three-dimensional substrates have to be coated. We have developed processes for the deposition of conductive, boron-doped diamond films as well as for tribological crystalline diamond coatings on deposition areas up to 50 cm × 100 cm. Such multi-filament processes are used to produce diamond electrodes for advanced electrochemical processes or large batches of diamond-coated tools and parts, respectively. These processes demonstrate the high degree of uniformity and reproducibility of hot-filament CVD. The usability of hot-filament CVD for diamond deposition on three-dimensional substrates is well known for CVD diamond shaft tools. We also develop interior diamond coatings for drawing dies, nozzles, and thread guides.Hot-filament CVD also enables the deposition of diamond film modifications with tailored properties. In order to adjust the surface topography to specific applications, we apply processes for smooth, fine-grained or textured diamond films for cutting tools and tribological applications. Rough diamond is employed for grinding applications. Multilayers of fine-grained and coarse-grained diamond have been developed, showing increased shock resistance due to reduced crack propagation.Hot-filament CVD is also used for in situ deposition of carbide coatings and diamond-carbide composites, and the deposition of non-diamond, silicon-based films. These coatings are suitable as diffusion barriers and are also applied for adhesion and stress engineering and for semiconductor applications, respectively.     

等离子体化学气相沉积参量对Ar等离子体电子特性的影响

采用加热的调谐单探针技术。研究了射频辉光放电Ar等离子体空间电子能量分布函数,电子平均能量和电子密度,并系统分析了等离子体增强化学气相沉积工艺参量对等离子体空间电子特性的影响。     

Laterally organized carbon nanotube arrays based on hot-filament chemical vapor deposition

Lateral porous anodic alumina (PAA) templates were used to organize carbon nanotubes (CNTs) grown by a hot-filament assisted chemical vapor deposition (HFCVD) process. For the CNT growth, we used a modified “home-made” HFCVD system with two independently powered filaments which are fitted respectively on the methane (CH₄) gas line, which serves as a carbon precursor and on the hydrogen (H₂) gas line, which acts as an etching agent for the parasitic amorphous carbon. Various activation powers of the hot filaments were used to directly or indirectly decompose the gas mixtures at relatively low substrate temperatures. A parametric study of the HFCVD process has been carried out for optimizing the confined CNTs growth inside the lateral PAA templates.     

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...     

两段成长法改善微波电浆辅助化学气相沉积多晶金刚石之品质

以化学气相沉积法成长多晶金刚石薄膜时,薄膜的品质会受到成长时间、成长压力、反应气体比例、偏压与否及成核的机制等因素影响.研究采用微波电浆辅助化学气相沉积(MPECVD)法,以甲烷(CH4)和氢气(H2)作为反应气体原料,在P型(111)硅基板沉积多晶金刚石薄膜.典型沉积多晶金刚石薄膜的制程可分为四个阶段:抛蚀表面阶段、渗碳阶段、偏压增强成核(BEN)阶段及成长阶段.研究将成长阶段划分为两个阶段,第一阶段压力较低(成长Ⅰ阶段),第二阶段压力较高(成长Ⅱ阶段).结果表明:第一阶段可大大改善金刚石薄膜的品质,所获多晶金刚石薄膜的晶粒具有明确的颗粒边界、较低的碳化物或缺陷,电导率急剧降低,显现出本徵金刚石半绝缘的性质.可以认为金刚石薄膜品质的改善完全为低压成长所致.实验发现在成长Ⅰ阶段或成长Ⅱ阶段施加偏压时,只会降低多晶金刚石薄膜的品质.     

热阴极辉光放电对金刚石膜沉积的影响

研究了在热阴极辉光放电等离子体化学气相沉积金刚石膜过程中，热阴极辉光放电特性与金刚石膜沉积工艺的关系．结果表明，适当的阴极温度是保证大电流、高气压辉光放电的必要条件．阴极的温度影响辉光放电阴极位降区的放电性质．金刚石膜的沉积速率随着气体压力(16～20kPa)的升高而上升，在18.6kPa左右出现最高值，而阳极位降区电场强度的降低使膜品质下降．放电电流(8～12A)对沉积速率的影响与气体压力的影响具有相似的规律．     

Combinatorial initiated chemical vapor deposition (iCVD) for polymer thin film discovery

Initiated chemical vapor deposition (iCVD) is a technique used to synthesize polymer thin films and coatings from the vapor phase in situ on solid substrates via free-radical mechanisms. It is a solventless, low-temperature process capable of forming very thin conformal layers on complex architectures. By implementing a combinatorial approach that examines five initiation temperatures simultaneously, we have realized at least a five-fold increase in efficiency. The combinatorial films were compared to a series of blanket films deposited over the same conditions to ensure the combinatorial system provided the same information. Direct synthesis from the vapor phase allows for in situ control of film morphology, molecular weight and crosslinking, and the combinatorial system decreases the time required to find the relationship between these interrelated properties. Some coatings were tested for antimicrobial performance against E. coli and B. subtilis.