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。     

等离子热丝化学气相沉积金刚石膜工艺参数研究

采用等离子热丝化学气相沉积(PHFCVD)装置进行了金刚石薄膜的制备实验。实验条件为：氢气流量为200sccm,甲烷流量为2～12sccm,基体温度为700～900℃,偏压为0～400V,真空室压力为4kPa。通过实验得出了甲烷含量、基体温度和偏压对沉积金刚石膜的影响,并运用扫描电子显微镜(SEM)、原子力显微镜(AFM)和X射线衍射(XRD)等测试方法对金刚石薄膜进行了观察分析。     

等离子体化学气相法沉积金刚石薄膜

本文介绍和评述了化学气相沉积法制备人造金刚石薄膜及其进展，重点评述了反应机理，发展历史，沉积方法，补底材料，检测手段，论述了有利于形成立方晶系金刚石材料的沉积条件。     

电子回旋共振微波等离子化学气相沉积金刚石薄膜

采用国内研制的电子回旋共振化学气相沉积设备(ECRCVD),在单晶硅片上沉积出了金刚石薄膜。通过扫描电子显微镜(SEM),X 射线衍射仪(XRD),激光拉曼谱仪(RAM)的测试,证明所沉积的薄膜具有明确的金刚石特征。所采用的 ECRCVD 设备,具有可以低压沉积、大面积均匀生长以及低温生长的优点。这种方法在合成金刚石光学膜,半导体膜以及其它薄膜方面有重要的应用前景。     

等离子体化学气相法沉积金刚石薄膜

本文介绍和评述了化学气相沉积法制备人造金刚石薄膜及其进展。重点评述了反应机理、发展历史、沉积方法、补底材料、检测手段。论述了有利于形成立方晶系金刚石材料的沉积条件。     

化学气相沉积（CVD）法制晶体金刚石的机理

引言现在正用低压气体来制造晶体金刚石而不是过去传统考虑的高温高压。生产金刚石的气相沉积过程所用的温度和压力条件对碳来说其稳定形式是石墨。然而,动力学因素允许通常是纯化学反应来形成的金刚石     

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。     

微波等离子体化学气相沉积金刚石簿膜

建立了一台微波等离子体化学气相沉积金刚石薄膜的设备。该实验装置由以下几部分组成：微波源及传输系统、反应室、供气系统、真空系统和检测等五部分组成。沉积室是由长７０ｍｍ直径４６ｍｍ的石英管组成的。分别采用ＣＨ４／Ｈ２和ＣＯ／Ｈ２混合气体进行了沉积试验；研究了沉积参数对沉积金刚石膜的影响。在直径３０ｍｍ的单晶硅片和石英片上沉积出了均匀的金刚石膜。采用ＣＨ４／Ｃ２混合气体时，沉积速率在０．５～１．０μｍ／ｈ之间，这与原有的热灯丝方法相近。采用ＣＯ／Ｈ２混合气体时，沉积速率可达到１．７μｍ／ｈ。     

Formation and characterization of diamond crystals synthesized by microwave plasma CVD system

Abstract

Diamond crystals have been successfully synthesized on (100) Si wafer using microwave plasma CVD. The growth was conditioned in a flowing system in which the parameters, such as CH₄/H₂ ratio, pressure, temperature and microwave power were varied. Cubo‐octahedra or tetrakaidecahedra are the equilibrium shape of diamond single crystals obtained under all conditions and are therefore the basic unit for the formation of polycrystalline diamond films, mostly through repetitive twinning and secondary growth of diamond crystals on {100} habit planes of cubo‐octahedra. Both X‐ray diffraction and Raman spectroscopy were used to facilitate the analysis of the diamond crystallinity and purity. These qualities are similar to those of natural diamonds.     

DC Arc Plasma Jet CVD金刚石自支撑膜的质量对物理性能的影响

本研究对Raman谱进行高斯（Gauss）和洛仑兹（Lorenz）分峰拟合，将金刚石自支撑膜Raman谱分成纯金刚石峰和非金刚石峰，对比两种方法的精度，结果显示高斯拟合的精度高些。运用经验公式计算出金刚石自支撑膜的质量因子，发现质量因子主要受纯金刚石峰强度和无定型碳峰强度的影响，非金刚石峰强度与质量因子成反比，纯金刚石峰强与质量因子成正比，同时还受到内应力的影响。质量因子与热导率、断裂强度和红外透过率的关系表明，金刚石自支撑膜的以上物理性能与其质量成正比关系。     

Electrochemical studies of nano-structured diamond thin-film electrodes grown by microwave plasma CVD

In this paper, we report the investigation of the electrochemical properties of nano-structured diamond thin-film electrodes on porous silicon (PSi) synthesized by microwave plasma chemical vapor deposition (MPCVD). For the application, boron-doped and undoped diamond thin film has been performed and fabricated into an electrode device, and its microstructure, electrical and chemical properties have been studied. In order to enlarge the surface area of diamond electrodes, a negative bias was applied to the MPCVD process to deposit diamond thin film in a nano-structured form, so that its surface remained rough and nano-fine structured. Diamond thin films were analyzed by Raman spectroscopy and SEM. The morphology of boron-doped diamond thin films on PSi reveals nano-rods in the shape of diamond crystallites. Their electrochemical properties were evaluated by performing cyclic voltammetry (CV) measurement in inorganic K₄[Fe(CN)₆] in a K₂HPO₄ buffer solution. Boron-doped diamond thin film on PSi has demonstrated good electrochemical properties, with a larger redoxidation current of CV, due to its rough surface, which provides a more active electrochemical interface.     

CVD diamond layers for electrochemistry

Diamond electrodes of different morphologies and qualities were manufactured by hot filament chemical deposition (HF CVD) techniques by changing the parameters of diamond growth process. The estimation of diamond quality and identification of different carbon phases was performed by Raman spectroscopy measurements. The effect of diamond quality and amorphous carbon phase content on the electrochemical response of an obtained diamond electrode in 0.5 M H₂SO₄ as supporting electrolyte was investigated by cyclic voltammetry with [Fe(CN)₆]^4?/3? as a redox probe. The kinetic parameters such as catalytic reaction rate constant k₀ and electron transfer coefficient α were determined. The obtained results show that the analytical performance of undoped diamond electrodes can be implemented just by the change of diamond layers quality.     

Porous silicon capping by CVD diamond

In the last few years important research efforts were put concerning the optical properties of porous silicon (PS). Some interesting devices can be made using this new material (ex: L.E.D.s and micro cavities). However, a set of unsolved problems is keeping some distance between PS and its applications. Among these problems are the chemical instability and mechanical weakness.In this work, we attempted a CVD diamond protective layer deposition on PS. The optical properties of PS were preserved, as confirmed by photoluminescence (PL). The diamond film adhesion was checked by microhardness testing showing no crack propagation with a load of 200 gf. Nanoindentation measurements with 0.1 gf on the resulting surface showed a ten fold increase in hardness with respect to the uncoated material.     

Nucleation control of diamond synthesized by microwave plasma CVD on cemented carbide substrate

Diamond was coated on to cemented carbide substrate by microwave plasma CVD, in which nucleation control of diamond crystals was investigated under constant deposition conditions; total pressure 30 torr, CH₄ flow rate 1 ml min^–1, H₂ flow rate 199 ml min^–1 and microwave power 550 W. Nucleation tends to occur selectively on the edge part of WC grains of the cemented carbide substrate with coarse WC grain size of about 1 m, where the nucleation density was 9×10⁶ cm^–2. The density increased to about 5×10⁷ cm^–2 when using a finegrained substrate (WC grain size 0.5 m). A considerably enhanced nucleation was observed by introducing a number of fine microflaws on to the substrate surface. Microflawing treatment with diamond fine powder (grain size 0–1/4 m) suspended in an ultrasonic cleaner bath was effective for increasing the diamond nucleation density up to 5×10⁸ cm^–2. The grain size of grown diamond crystals decreased with increasing microflawing time.     

非晶金刚石离子镀膜机自动化控制系统的设计

结合非晶金刚石离子镀膜机的工艺特点和要求，本文介绍了一种成功应用的分布式控制系统的设计，重点讨论了控制系统的硬件配置、软件设计、通信服务程序以及软件编程中的几个控制算法。     

PLC数字折页机纸张自动预置控制系统设计

针对传统折页机中人工纸张规格预置工作量大、较为繁琐且人为误差较大的状况,将容栅传感器检测技术和PIE控制技术用于数字折页机的纸张规格自动预置系统中,设计了硬件控制系统和软件程序。采用高精度容栅传感器及其配套的实时检测器进行数据采集和转换,通过触摸屏实现人机界面的通讯,通过PIE驱动步进电机实现纸张规格自动预置功能,并给出了应用程序和实验结果。     

CVD金刚石紫外探测器

CVD金刚石紫外探测器有极强的辐射硬度及耐腐蚀性,在宽禁带半导体紫外探测器中占有重要地位.本文主要对金刚石紫外探测器的发展进展、探测机理、电极模式及应用领域做了简要回顾.