脉冲真空电弧离子源工艺参数对薄膜厚度分布的影响

薄膜厚度的均匀性是影响沉积方法应用的一个重要的因素，利用脉冲真空电弧离子镀技术在Si基片上沉积山类金刚石薄膜，采用轮廓仪对膜的厚度进行了测量，研究服不同工艺参数对薄膜均匀性的影响。实验结果表明：脉冲离子源阴极和基片的距离，主回路工作电压以及沉积频率对薄膜均匀性有不同程度的影响。根据分析结果，找出最佳工艺参数，通过比较两种离子源的结果表明，离子源结构对其镀膜均匀性有较大的影响。     

脉冲电弧源的发射特性建模

脉冲电弧源是脉冲电弧离子镀方法制备薄膜的重要部件，其发射特性是影响薄膜均匀性的重要因素，本文从理论出发，建立脉冲电弧源发射特性的数学模型，编程计算得到理论的均匀性曲线，与实际的沉积薄膜厚度的均匀性对比，结果表明：脉冲电弧源的蒸发特性可以等效于多个面源的叠加，每一个面源发射的离子密度空间分布符合余弦定律。     

霍尔离子源制备类金刚石薄膜研究

采用霍尔离子源沉积类金刚石薄膜是近年来新出现的一种方法，本文研究了自行研制的霍尔离子源的性能以及采用此离子源制备类金刚石薄膜及工艺参数的影响。结果表明，霍尔离子源在较低的电压即可起辉，可提供稳定的能量较低的离子束流。采用霍尔离子源沉积类金刚石薄膜的沉积速率约为O．5nm/s。随着霍尔离子源灯丝电流的升高，离子源放电电压下降，制备的类金刚石薄膜的硬度下降。放电电流的变化对类金刚石薄膜的硬度影响不大。     

增强型脉冲离子源镀制DLC薄膜拉曼光谱研究

本文利用增强型脉冲电弧离子源在硅基底上沉积类金刚石薄膜，拉曼光谱分析表明DLC薄膜中sp^3键含量比不加磁过滤装置时脉冲离子源所镀的类金刚石薄膜高，折射率更接近金刚石折射率2．4并且光学带隙也增大，证明用增强型脉冲离子源镀制的类金刚石薄膜sp^3键含量提高，性能得到了很大改善。     

过滤电弧抑制薄膜中颗粒机理的实验分析

讨论利用直线型过滤电弧制备TiAlN薄膜中,过滤磁场作用于弧斑、靶中毒现象,电子和离子的回流和叠加偏压等因素影响作用的大小进行了实验分析.结果表明,磁场对弧斑分裂和弧斑运动速度的综合作用最为显著是由于直线型过滤电弧形成的瓶颈磁场造成的电子和离子的回流,以及直流叠加脉冲偏压形成的放电空间的等离子体磁撞,分解和离化的所起的共同作用的结果.这对于控制电弧离子镀沉积薄膜中的颗粒尺寸和颗粒密度,指定合理的工艺参数有一定的指导作用.     

霍尔离子源制备类金刚石薄膜研究

采用霍尔离子源沉积类金刚石薄膜是近年来新出现的一种方法 ,本文研究了自行研制的霍尔离子源的性能以及采用此离子源制备类金刚石薄膜及工艺参数的影响。结果表明 ,霍尔离子源在较低的电压即可起辉 ,可提供稳定的能量较低的离子束流。采用霍尔离子源沉积类金刚石薄膜的沉积速率约为 0 5nm/s。随着霍尔离子源灯丝电流的升高 ,离子源放电电压下降 ,制备的类金刚石薄膜的硬度下降。放电电流的变化对类金刚石薄膜的硬度影响不大。     

贫铀表面Ar气脉冲辉光放电清洗

贫铀极易氧化,为了提高其表面薄膜的结合性能,薄膜沉积前铀表面的辉光放电清洗是极为重要的。利用计算机模拟对Ar气脉冲辉光放电等离子体特性进行了研究,采用俄歇电子能谱仪(AES)对辉光放电清洗后铀表面化学元素进行了分析,同时对铀表面铝薄膜界面元素分布进行了深度剖析。结果表明:氩分压和脉冲电压是影响辉光放电等离子体特性的关键因素;脉冲电压和氩分压越高,辉光放电等离子体中Ar+密度越大;脉冲电压辉光放电清洗效果优于直流电压;在2.0Pa氩分压、-900V脉冲电压下,等离子体Ar+密度高达1.29×1014/m3,采用该参数对铀表面进行清洗可以获得洁净的表面,并有利于薄膜原子向铀基体内部迁移,促使膜基界面"伪扩散层"的增宽,从而增强铀表面薄膜的结合性能。     

宽束离子源的均匀性分析

在离子束溅射和离子辅助沉积光学薄膜技术中，离子源是其中最关键的单元技术之一。通过测试宽束离子源束流密度的空间分布，研究了影响离子束均匀性分布的两个主要因素；加速电压和E／B。结果表明，随着加速电压的增加，离子束束流密度的分布趋向均匀；而E／B对离子束均匀性的影响不大。     

真空阴极电弧离子源磁场分析与设计

真空阴极电弧离子源是多弧离子镀膜设备的核心部件,直接影响镀膜系统的整体性能。真空阴极电弧离子源在工作时,大液滴发射是阻碍电弧离子镀技术广泛深入应用的瓶颈问题。合理设计并利用磁场可以很好地控制弧斑运动,大幅度地减少液滴、减小液滴尺寸、提高膜层质量和使用寿命。对真空阴极电弧离子源的附加磁场进行了理论分析和仿真计算,为附加磁场的优化设计提供了重要的指导依据。     

脉冲真空弧离子源的质谱分析

本文介绍了脉冲真空弧离子源的特点,建立了脉冲真空弧离子源工作瞬间放气成分的质谱分析系统.应用四极质谱仪记录了真空系统中离子源工作前后的谱图,并通过数据软件的二次处理初步取得了脉冲真空弧离子源放电空间的增量成分分析;开展了不同绝缘介质对脉冲真空弧离子源工作瞬间所产生气体成分的对比研究.     

一种新型复合加速离子注入动力学研究

提出了一种基于靶台(工件)二次加速的束线离子注入的新方法,基本原理是将传统束线离子注入和等离子体离子注入有效复合。采用二维Particle-in-cell(PIC)模型对这种注入方法进行了数值仿真研究。考察了靶台加负偏压情况下靶台表面空间电势、离子密度变化以及离子的运动状态的时空演化。统计分析了不同时刻离子注入剂量、注入能量和注入角度的分布规律。结果表明:靶台施加偏压对束流离子起到了很好的二次加速效果,束线离子复合加速离子注入这种新方法理论上是切实可行的。同时发现在靶台附近空间电场的作用下,离子束会发生小角度偏转,由柱状形逐渐变成"喇叭口"形,靶台表面有效注入范围扩大。靶台表面注入剂量分布呈中心区域高边缘区域低的趋势。这种新方法有助于减缓电源硬件加工的难度,增加了工艺的灵活性。     

Effect of the Angular Distribution of Cathode Ions on the Current Flow in a High-Current Vacuum Arc

The effect of the angular distribution of cathode ions on the parameters of a vacuum arc is investigated. It is shown that, at current densities characteristic of a high-current arc, collisions of flows of fast ions from different cathode spots may result in a high value of the ion temperature at the cathode plasma boundary. The boundary in current density of the region of a stable current flow as a function of the width of angular distribution of cathode ions is determined. It is found that, in the region of supersonic flow of ions, the permissible value of the current density drops rapidly as the angular distribution width increases, and in the subsonic region, it rises rapidly. An expression is obtained for the maximum possible ion sound velocity and for the equivalent critical ion velocity. Two- and three-fluid hydrodynamic models are used to perform calculations that illustrate characteristic distributions of parameters in the discharge gap. Analysis of the calculation results makes it possible to discuss the characteristic features of current flow in a vacuum discharge.     

Experimental Verification of the Physical Model for Droplet-Particles Cleaning in Pulsed Bias Arc Ion Plating

It has been reported that application of pulsed biases in arc ion plating could effectively eliminate droplet particles. The present paper aims at experimental verification of a physical model proposed previously by us which is based on particle charging and repulsion in the pulsed plasma sheath. An orthogonal experiment was designed for this purpose, using the electrical parameters of the pulsed bias for the deposition of TiN films on stainless steel substrates. The effect of these parameters on the amount and the size distribution of the particles were analyzed, and the results provided sufficient evidence for the physical model.     

Partial currents of ion species in an expanding laser-created plasma

A novel analysis of ion currents, which is based on the use of shifted Maxwell-Boltzmann velocity distribution, is applied to quantify the properties of expanding laser-produced plasmas into the vacuum. The ion currents were measured outside the critical zone where the recombination and collisional excitation processes are not important and the charge-states of ions are frozen. The deconvolution of single-shot ion currents is applied for recovering the partial currents of participating ion species in the measured ion currents in carbon, copper and polyethylene plasmas created by various pulsed laser beams. This method allows determining the plasma temperature, the centre-of-mass velocities of individual charge-states and their abundance. The obtained charge-state dependencies of the centre-of-mass velocities render important details in establishing the mechanisms responsible for the ion emission, which has fundamental importance in applications of laser ion sources.     

Effect of Sample Configuration on Droplet-Particles of TiN Films Deposited by Pulse Biased Arc Ion Plating

Orthogonal experiments are used to design the pulsed bias related parameters,including bias magnitude, duty cycle and pulse frequency,during arc ion deposition of TiN films on stainless steel substrates in the case of samples placing normal to the plasma flux.The effect of these parameters on the amount and the size distribution of droplet-particles are investigated,and the results have provided sucient evidence for the physical model,in which particles reduction is due to the case that the particles are ne...     

Ion-pumping mechanism in a pulsed Penning source: application to the production of multiply charged ions

The neutral atom density of a low-duty pulsed Penning ionized-gauge ion source (PIGIS) is sharply pulsed, according to the pulsed ion current into the cathode, which should act as a periodic ion pump in the plasma column of PIGIS. A high yield of multiply charged ions (Ar⁸⁺, 250–300 eμA; Ar⁷⁺, 1000 eμA) can thus be obtained under a reasonably low gas pressure during a short time (of the order of millisecond), which is sufficiently long for injection (160 μs) into the heavy-ion medical synchrotron (HIMAC) at NIRS.     

真空舱背景压力对离子推力器栅极系统工作性能影响的数值模拟

离子推力器地面寿命试验中,真空舱背景压力是影响推力器性能的重要因素之一。采用二维PIC/MCC方法对栅极系统受背景压力影响进行研究。模拟得到了20 cm离子推力器不同背景压力下栅极系统的电势分布、束流离子空间分布、单位时间内碰撞到加速栅极孔壁和下游表面的交换电荷数目、加速栅极电流等。计算结果与试验测得值很吻合,加速栅极下游表面的溅射腐蚀受背景压力的影响大于其孔壁腐蚀影响,考虑试验成本,可将地面试验真空舱背景压力设为5×10-4Pa。     

Plasma investigation of PVD processes operating in dc continuous and/or dc pulsed mode

The plasma of different dc and dc pulsed pvd processes (TiN and Ta²O⁵ magnetron sputtering, Ta²O⁵ ion plating) has been investigated by means of a mass spectrometric plasma monitoring system PPM421 (Inficon). The ion energy distribution of the process relevant positive ions has been measured and the dependence of the plasma properties on the process parameters like pulse frequency and pulse voltage was analysed. Starting with an overview concerning a theoretical concept behind the plasma properties in dc pulsed sputter processes, theoretical predictions from this theory about the kinetic energy of the ions and the shape of the ion energy distribution are compared with the experimental results in different dc pulsed sputter processes. A significant difference can be seen in level and distribution of the ion energy in conventional dc magnetron processes compared to dc pulsed processes. The process parameters pulse frequency and pulse voltage control the kinetic energy of the process ions. The theoretically predicted properties of a pulsed plasma could experimentally be confirmed.     

Generation of electrical defects in ion beam assisted deposition of Cu(In,Ga)Se2 thin film solar cells

Thin films of Cu(In,Ga)Se₂ (CIGS) absorber layers for thin film solar cells have been manufactured on polyimide foil in a low temperature, ion beam assisted co-evaporation process.In the present work a set of CIGS thin films was produced with varying selenium ion energy. Solar cell devices have been manufactured from the films and characterized via admittance spectroscopy and capacitance-voltage profiling to determine the influence of the selenium ion energy on the electric parameters of the solar cells. It is shown that the impact of energetic selenium ions in the CIGS deposition process leads to a change in the activation energy and defect density and also in the spatial distribution of electrically active defects.For the interpretation of the results two defect models are taken into account.