ECR等离子体刻蚀CVD金刚石膜的研究

在自主设计的具有非对称磁镜场位形的ECR等离子体装置上进行CVD金刚石膜的刻蚀实验,研究了基片温度、工作气压和磁场位形三个工艺参数对刻蚀效果的影响.实验结果表明:通过此方法刻蚀的CVD金刚石膜,其晶粒顶端被优先刻蚀,表面粗糙度降低.实际数据显示,刻蚀温度为20℃和150℃时,后者的刻蚀效果更好;工作气压为2×10-3 Pa和3×10-2 Pa时,前者的刻蚀效果更好;磁场强度为0.2T和0.15T时,前者的刻蚀效果更强.     

氢等离子体在铁催石墨化作用下对CVD金刚石膜的刻蚀

在铁薄膜的催石墨化作用下研究了用氢等离子体刻蚀由微波等离子体化学气相沉积（MPCYD）制备的多晶金刚石厚膜的表面。其工艺为：自支撑的金刚石厚膜浸入饱和的三氯化铁水溶液中，然后平放在大气环境中干燥，将处理过后的金刚石膜放入MPCVD装置中，先用氢等离子体将氯化铁还原成铁，然后在800℃左右的温度下，利用铁对金刚石的催石墨化作用及氢等离子体的刻蚀作用将其表面刻蚀。刻蚀完后的金刚石用酸清洗，在丙酮溶液中漂洗，然后用SEM观察刻蚀效果，用Raman光谱对表面碳的结构进行了表征。最后用机械研磨法对金刚石样品表面进行研磨，并对研磨结果进行对比。实验结果表明，这种方法能够有选择地快速刻蚀金刚石膜的表面，破坏表面晶粒的完整度，降低表面耐磨性，从而提高对粗糙金刚石膜表面研磨的效率。     

图形化CVD金刚石膜的新方法——等离子体辅助固体刻蚀法

金刚石膜是一种具有巨大应用潜力的新型功能材料,但是它极高的硬度和化学稳定性使其难以被加工成型,因此如何对金刚石膜表面进行精确的图形化加工是实现制造金刚石器件的关键技术问题之一.在本研究中,我们用微波等离子体化学气相沉积法制备的金刚石厚膜,在其表面利用氢等离子体辅助刻蚀、铁薄膜的催石墨化作用下,对金刚石膜的形核面进行了选择性的刻蚀.结果表明,该方法具有较高的刻蚀速率(850 ℃,33.8 μm/h),较高的刻蚀选择比,可以对CVD金刚石膜进行较精确的图形化刻蚀,还可通过调节铁薄膜的厚度来实现刻蚀深度的控制.对氢等离子体在整个过程中的作用进行了阐述.     

直流辉光等离子体的边缘效应

结合辉光渗氮试验结果,对直流辉光等离子体材料处理中的边缘效应进行了研究,根据相关鞘层理论,对工件边角处及其附近的鞘层厚度S、电场强度E及离子密度n进行了定性分析。结果表明：在边缘效应范围d内,当远离边角时,S将变大、E及n变小。主等离子体密度n0的减少将使边缘效应的影响范围d变大,因此降低工作气压P及电流I可减弱边缘效应。采用改进措施渗氮后,工件边缘效应得到抑制,且渗氮效果较好。     

铁刻蚀CVD金刚石膜辅助机械抛光

采用直流溅射方法在化学气相沉积(CVD)金刚石膜表面镀上一层铁薄膜,在氢等离子体条件下利用铁对金刚石膜的快速刻蚀实现初抛光,然后再进行机械抛光,提高抛光效率。     

射频辉光放电等离子体辅助化学气相沉积法制备类金刚石碳膜工艺与性能表征

使用射频辉光放电等离子体辅助化学气相沉积技术（简称RFGDPECVD）在玻璃载玻片表面沉积类金刚石薄膜。用原子力显微镜（AFM）、摩擦试验仪、划痕试验机测定了其表面形貌、耐磨性及附着性。采用X射线光电子能谱（XPS）、分光光度计对两种气源（C4H10、C2H2）制备的DLC薄膜微观组成和透光率进行了检测和对比。结果表明：DLC薄膜的表面光滑、平整,表面粗糙度随沉积时间的增加单调递增;耐磨性及附着性优良;与C4H10相比使用C2H2作为碳源气体可以得到较高Sp^3含量和较低Sp^1含量的DLC膜;C2H2制备DLC薄膜的透光率低于C4H10;同一种碳源气体,反应流量比例越小,则DLC薄膜的透光性越好。     

直流电弧等离子体CVD金刚石膜工艺参数优化

为了研究工艺对CVD金刚石膜生长的影响,本文采用电镜、激光Raman谱分析等手段研究工艺参数对CVD金刚石膜生长速率和生长质量的影响.结果显示:金刚石薄膜的生长速率随甲烷浓度(3%～10%)、基片温度(800～1200℃)的增加而增加,随工作气压的升高先是增加,而后降低,峰值在15～20 kPa处.金刚石薄膜中非金刚石碳的相对含量先随基片温度的增加逐渐降低,在1080～1100 ℃达到最小值以后又开始急剧增加,膜的质量(结晶形态好和非金刚石碳的相对含量少)在1080～1100 ℃处达到最佳.     

直流电弧等离子体喷射在金刚石膜制备和产业化中的应用

综述了北京科技大学在直流电弧等离子体喷射CVD金刚石膜沉积系统研制和改进及大面积高质量(包括光学级)金刚石自支撑膜沉积的研究进展和产业化状况.用同样技术研发出了可用于复杂形状硬质合金工具金刚石膜涂层工具批量生产的强电流直流伸展电弧等离子体CVD金刚石膜涂层系统,讨论了利用该设备研发金刚石膜涂层硬质合金工具及其现场切削试验的结果.     

加弧辉光离子渗铝的研究

介绍了加弧辉光离子渗铝新工艺,并对普通碳钢进行了加弧辉光离子渗铝处理。研究了10、60、T12钢渗铝后的渗层组织特点,渗层合金成分的分布、渗层相组成及工艺参数对铝层的影响规律。     

直流电弧等离子体喷射法制备金刚石自支撑膜研究新进展

文章综述了以直流电弧等离子体喷射法制备自支撑金刚石膜的研究新进展,对电弧特性、金刚石晶体质量、力学性能、光学性能及热学性能进行了介绍。研究表明:不同电弧区域的金刚石膜结晶质量及应力状态有所差异,钛过渡层可以降低金刚石的残余应力;采用四点弯曲测得金刚石的断裂韧性为10.99 MPa·m1/2;一定温度范围内,金刚石吸收系数与温度的关系基本不受金刚石质量和厚度的影响;金刚石的光学性能越好,其热导率越高,且金刚石形核面热导率略高于生长面,500 K以上时多晶金刚石膜的热导率近似于单晶水平。      

Reduction of TiO2 with hydrogen cold plasma in DC pulsed glow discharge

The reduction of TiO2 to Ti2O3 with hydrogen cold plasma generated by a DC pulsed glow discharge was realized under 2 500 Pa at 1 233 K. Only a little of Ti10O19 and Ti9O17 was detected for using molecular hydrogen.Enhancement effects of hydrogen cold plasma on the reduction were discussed in terms of thermodynamic coupling,kinetics and plasma sheath. The exited hydrogen species are considered more effective reducing agents. It is instructive to reduce refractory oxides with plasma hydrogen at the reduced temperature.     

Effects of deposition parameters on microstructure and thermal conductivity of diamond films deposited by DC arc plasma jet chemical vapor deposition

The uniform diamond films with 60 mm in diameter were deposited by improved DC arc plasma jet chemical vapor deposition technique. The structure of the film was characterized by scanning electronic microcopy(SEM) and laser Raman spectrometry. The thermal conductivity was measured by a photo thermal deflection technique. The effects of main deposition parameters on microstructure and thermal conductivity of the films were investigated. The results show that high thermal conductivity, 10.0 W/(K-cm), can be obtained at a CH4 concentration of 1.5% (volume fraction) and the substrate temperatures of 880-920 ℃ due to the high density and high purity of the film. A low pressure difference between nozzle and vacuum chamber is also beneficial to the high thermal conductivity.     

椭球形微波等离子体金刚石膜沉积装置与金刚石膜的制备

对椭球形谐振腔式微波等离子体(MPCVD)金刚石膜沉积装置的谐振腔进行了模拟,获得了谐振腔中的电场和等离子体分布。运用自行设计和建立的椭球形谐振腔式微波等离子体装置,沉积了纳米和微米尺度的金刚石膜。对金刚石膜的各种性能进行了检测。结果表明,所建成的椭球形谐振腔式的MPCVD金刚石膜沉积装置,可实现微米和纳米尺度不同品质金刚石膜的沉积。     

强电流直流伸展电弧等离子体CVD金刚石沉积均匀性研究

采用特殊的等离子体技术成功研制出适合于金刚石涂层工具工业化生产的中试设备-强电流直流伸展电弧等离子体CVD-500型中试设备。单腔体沉积的沉积工件数量在100支以上;对该设备的沉积均匀性进行了系统的研究,位于等离子体扩散区同一柱面不同位置沉积的金刚石形貌及质量均匀、一致,涂层厚度的不均匀度在±3．5％的范围内;同一沉积试件不同位置处的金刚石形貌及质量稍有差别,但均在许可范围之内,涂层厚度的不均匀度在±2％的范围内;等离子体的扩散区的径向6 cm～8cm,轴向距阳极7 cm-19cm的范围为该设备的有效沉积区域。     

强电流直流伸展电弧CVD纳米金刚石涂层微型工具

本文研制了强直流伸展电弧金刚石涂层沉积设备,它可产生长达400 mm的等离子体弧柱,可沉积金刚石涂层的区域大,能够在复杂形状硬质合金刀具上沉积金刚石涂层,有利于实现金刚石涂层硬质合金工具的产业化生产.在直径1 mm的微型铣刀上沉积了纳米金刚石涂层,研究了沉积压力对金刚石涂层组织的影响,沉积压力对金刚石涂层的晶粒尺寸和表面形貌有显著影响.随着沉积压力的降低,沉积的金刚石涂层晶粒尺寸减小,当沉积压力为0.80 kPa时,可沉积出纳米金刚石涂层.涂层的厚度均匀,其表面光滑、平整,且与硬质合金基体之间有较好的附着力.用激光Raman对金刚石涂层进行了表征.     

Deposition and etching of fluorocarbon thin films in atmospheric pressure DBDs fed with Ar-CF4-H2 and Ar-CF4-O2 mixtures

The deposition and etching of plasma-polymerized fluorocarbon thin films were studied in filamentary dielectric barrier discharges (FDBDs) fed with Ar-CF₄-H₂ and Ar-CF₄-O₂ mixtures, respectively. The etching/polymerization competition was investigated as a function of the feed composition.Hydrogen addition to CF₄ promotes thin films deposition, with a maximum deposition rate at 20% H₂, and reduces the F/C ratio of the deposit, while the oxygen addition promotes the etching of the plasma-deposited film. It is demonstrated that fluorine atoms can perform the etching of the fluoropolymer also without ion bombardment. The correlation between the trend of the etch rate and the trend of the surface chemical composition of fluoropolymers etched in Ar-CF₄-O₂ mixtures allows to enhance hypotheses on the reaction mechanism and on the role of the different active species involved in plasma-surface interactions.     

Growth mechanism of polycrystalline Ir coating by double glow plasma technology

Pure Ir coating was produced by double glow plasma technology.Growth mechanism of the Ir coating was investigated.The Ir coating was composed of irregular compacted columnar grains with lots of nanovoids appeared on the interface between the coating and the substrate.The Ir coating was polycrystalline with a preferred (220) orientation due to the initial nuclei with preferred growth on the surface of the substrate.The formation mechanism of the Ir coating depended on kinetic adsorption and diffusion process with nucleation,coalescence and thickness growth.At the beginning of the deposition process,the growth mode of the coating was mainly controlled by the nucleation rate.Due to the low substrate temperature resulting in low mobility of the deposited atoms,some micropores and nanoviods were present at the interface.With the deposition process,the substrate temperature was increased and then kept steady.The growth of the coating was governed by the growth rate.The high substrate temperature supported enough energy to surface mobility of adatoms.     

干法刻蚀图形化CVD金刚石膜研究进展

CVD金刚石膜因其极高的强度和耐磨特性在微机电系统(MEMS)领域具有极好的应用前景,然而其极高的硬度和化学惰性又使其很难被加工成型,这极大地限制了CVD金刚石膜在MEMS领域的应用。本文主要介绍了近年来干法刻蚀图形化CVD金刚石膜的研究进展,系统地分析了激光刻蚀,等离子体刻蚀,等离子体辅助固体刻蚀的原理及其各自优缺点,着重论述了国内外采用等离子体刻蚀CVD金刚石膜的研究现状。     

Influence of intermittently etching on quality of CVD diamond thin films

A new method, called growing-etching repetitional process based on hot filament chemical vapor deposition, was proposed to improve the quality of diamond film. During the deposition carbon source was intermittently closed letting hydrogen etch the surface of the diamond film fi＇om time to time. In order to find whether it is helpful to the films＇ quality, a series of experiments were done. The results show that the new method can enhance the orientation of the chemical vapor deposition diamond films, reduce the graphite phase and increase the film＇s surface resistivity.