Measurement of Plasma Density in Brass Arc Plasma at Atmospheric Pressure Using a Langmuir Single Probe

In this work, we construct electrodes of brass to produce plasma by arc discharge and is characterized by using a movableLangmuir single probe. It is a simple w...     

Langmuir探针在等离子体诊断中的抗干扰方法

本文介绍了三种Langmuir探针在等离子体诊断中抗干扰的方法:积分平均技术--采用积分电路,有效抑制波动干扰,提高探针信噪比;滤波器--利用同轴电缆构成级连滤波器网络,消除射频源基频及谐频干扰;差分放大器--两根同轴电缆与差分放大器配合使用,消除由于同轴电缆电阻电容(RC)特性引起的诱导噪音.上述方法分别从抗干扰原理、抗干扰装置和实验结果三方面予以了说明,指出了目前使用Langmuir探针进行等离子体诊断时存在的问题,并提出了解决方案.     

PECVD镀膜机等离子体静电探针诊断

开发了一个朗缪尔探针等离子体诊断系统,对PECVD真空镀膜机进行了等离子体参数诊断.该镀膜机内的等离子体是电容偶合激发方式的氩等离子体,激发源为射频电源(13.56MHz).在射频功率为40W到140W的范围内,使用该朗缪尔探针对镀膜机中氩等离子体的参数(等离子体密度和电子温度)进行了诊断分析.结果表明:电子温度在2.7eV和6.4eV之间,并且随着射频功率的增加而降低.而等离子体的密度在0.85×1015m-3到8×1016m-3的范围随着射频电源的增加而增加.     

朗缪尔三探针方法脉冲火花放电等离子体诊断

根据强流脉冲电子束源结构及性能优化需求,准确测量脉冲等离子体的分布规律十分重要。基于脉冲火花放电等离子体产生机制和朗缪尔三探针工作原理,设计探针结构和诊断电路参数,满足空间分辨率7.5 mm³。通过数字示波器采集存储原始测量信号,利用Matlab软件编写数据处理程序,可计算得到电子温度和电子密度,其时间分辨率为0.04 μs。将探针置于束源出口位置进行测量,对应真空度7.0×10^-3Pa和放电电压8000 V条件下,等离子体峰值电子温度为3.8 eV,电子密度为4.0×10¹⁸m^-3。在不同放电条件下测量,发现等离子体的电子温度随工作气压增大而减小,电子密度与之相反,提高放电电压时,电子温度和电子密度均出现增大,符合理论分析和实验规律。因此,本文所研制的诊断系统满足脉冲放电等离子体测量要求。     

等离子体的Langmuir探针诊断及数值滤波

Ｌａｎｇｍｕｉｒ探针是诊断等离子体荷粒子参数的重要手段。本文首次报道了用加热的调谐探针,在抑制了对探针的射频干扰和“中毒效应”之后,对探针Ｉ－Ｖ曲线的统计涨落噪声进行了数字滤波的光滑化处理,获得了射频辉光放电硅烷等离子体的电子能量分布函数,平均能量和浓度等重要参数。     

电子回旋共振等离子体源的朗谬尔探针诊断

电子回旋共振(ECR)等离子体以其密度高、工作气压低、均匀性好、参数易于控制等优点在超大规模集成电路工艺中获得了广泛的应用.利用朗谬尔探针对ECR等离子体进行了初步的诊断研究,测量了等离子体的单探针伏安特性并计算出电子温度,电子密度和等离子体电势等参量.实验证明,ECR等离子体源能够稳定地产生电子温度较低的高密度等离子体.     

直流磁控溅射辉光等离子体的Langmuir静电探针诊断

与大连理工大学合作研制了新型Langmuir静电探针.应用研制的静电探针,对氩气直流磁控溅射铜等离子体进行了轴向和径向二维空间内的诊断.诊断结果显示电子温度随着离靶面距离增大而递减;电子密度在径向和轴向均存在波动;电子能量主要分布在0 eV～5 eV范围内,高能电子占比例极少.     

Langmuir探针诊断微波ECR非平衡磁控溅射等离子体

利用朗谬尔探针诊断了ECR非平衡磁控溅射等离子体,给出了微观等离子体参量随宏观工艺参量变化关系.实验测得基片架附近等离子体密度达到1010～1011数量级,电子温度在(5～10) eV之间.随溅射靶功率变化,等离子体密度在130W时取得最大值;同样随微波源功率变化,等离子体密度在功率为850W时也达到最大值.电子温度、等离子体空间电位变化与等离子体密度呈相同趋势.     

脉冲等离子体推力器放电电流测量

为测量脉冲等离子体推力器（PPT）工作时产生的冲击大电流,设计了一种基于Rogowski线圈的放电电流测量系统,并采用Pearson 5046电流互感器对其进行对比和校正。简要介绍了该测量系统的组成和原理,分析了相关参数的选取,实验表明,该系统方便实用,测量准确,对系统影响较小。     

用Langmuir探针法标定的发射光谱法诊断等离子体电子密度及分布

电子密度是低温等离子体的重要参数之一,仅采用发射光谱或Langmuir探针一种诊断方法,很难测量出该参数及其分布。针对这一问题,提出了用Langmuir探针法标定的发射光谱法,用于诊断等离子体电子密度及其分布。通过对一定长度表面波等离子体源的实验测量,验证了该方法的可行性。对于电子温度变化不大的等离子体,利用本文提出的诊断方法,可以测量出其电子密度及其分布。提出的诊断方法为低温等离子体参数的实验诊断提供了一种新的途径。     

溅射沉积氢化非晶硅中辉光放电等离子体的Langmuir探针诊断

为揭示磁控溅射辉光放电等离子体参量对Si薄膜沉积过程的本质影响,采用Langmuir探针于不同的靶电流、靶基距和氢分压条件下对直流辉光放电等离子体进行了诊断,分析了直流辉光放电等离子体参量(离子密度、离子流通量、等离子体电势、电子密度、电子温度)的变化规律,并以此为依据探讨了其对Si靶溅射过程和溅射Si粒子输运过程的影...     

Time-of-Flight Mass Spectrometry with a Pulsed Glow Discharge Ionization Source

The pulsed glow discharge (GD) plasma source exhibits several characteristics that make it ideally suited for use with time-of-flight mass spectrometry (TOFMS). TOFMS uniquely affords the ability to monitor a narrow temporal window for a time-varying process such as ion formation in the pulsed glow discharge plasma. Pulsed GD-TOFMS exhibited distinct advantages for the direct determination of trace elements in solid state samples. Initially, the pulse-powered GD-TOFMS system used for these investigations exhibited poor resolution. In an effort to improve resolution, a slit was introduced to narrow the ion beam orthogonally entering the extraction region of the TOFMS. In an effort to determine optimal operating conditions, the influence of slit width on TOF performance was investigated. In the course of this study, the slit width was found to influence isotope ratio accuracy as well as resolution. A slit width of 1.0 mm was determined to provide the best compromise between resolution and isotope ratio accuracy. Pulsed GD-TOFMS affords improved sensitivity and selectivity because Penning ionization is enhanced during the time period immediately following the termination of the discharge power. Ions sampled by an extraction pulse applied after power termination also yield a mass spectrum that is free of contributions arising from electron-ionized interferences. This advantage arises because only ions generated via the Penning ionization mechanism persist after the termination of discharge power. Sampling in the "afterpeak" time regime eliminates the saturation of the detector arising from discharge support gas ion signal.     

Diagnostics of Flows of Pulsed Plasma by Probe, Microwave, and Photometric Methods

The methodology is suggested of complex diagnostics of pulsed plasma flows, which is based on a synchronous application of the probe, microwave, and photometric methods. The space-time distribution of the basic kinetic parameters are given under conditions of expansion of plasma clusters in vacuum and their interaction with an obstacle.     

Langmuir探针的中毒效应及其抑制

射频辉光放电硅烷等离子体化学汽相沉积是制备氢化非晶硅薄膜的主要工艺技术。探测和控制等离子体参数是选取最佳工艺条件、制备优质薄膜的关键问题。Ｌａｎｇｍｕｉｒ探针是获得等离子体荷电参数的诊断技术。本文分析了探针诊断技术中的一大难题－中毒效应产生的原因，提出并验证了用加热探针抑制中毒效应的机理。理论分析和实验结果表明，探针被加热升温到２００℃时，其中毒效应完全得到了抑制。     

静电离子探针在气体放电磁化等离子体参数测量中的应用

为测量气体放电磁化等离子体离子参数,建立了一套静电离子探针诊断系统,进行了从近芯部到边缘区的离子温度分布的测量,结果与常规朗缪尔探针对电子参数的测量结果吻合。     

Plasma characterization in sputtering processes using the Langmuir probe technique

The Langmuir probe technique, which has long been used in the field of plasma physics, can be a very powerful tool in characterizing the sputtering process. In this context, theoretical formalism, design requirements and the experimental procedures necessary for the application of this technique to both r.f. and d.c. sputtering are presented. It is shown that the plasma parameters can be determined in a simple way only if the probe operation is in the orbital motion limited regime. This condition is fulfilled for a cylindrical probe when the ratio of the probe radius to the Debye length of the plasma is less than 3. In the case of r.f. discharges erroneous data are obtained if a large r.f. current is flowing to the probe. This current can be blocked by a suitable LC circuit. Using the Langmuir probe technique the variations in the plasma parameters in d.c./r.f. sputtering discharges as a function of target voltage/power and argon pressure are determined.     

氦离子化检测器(PDHID)与火焰离子化检测器(FID)在高纯气体分析中的性能比较

简述了火焰离子化检测器(FID)与氦离子化检测器(PDHID)的结构、工作原理及其应用.通过对高纯气N2、H2、Ar、He、O2中杂质分析的比较,显示GC只需配有一个PDHID即可完成对元机与有机杂质的分析,而且PDHID具有更高的灵敏度、更低的检测限.     

Langmuir Probe Measurements in the Gaseous Electronics Conference RF Reference Cell

The use of a Langmuir probe system in two GEC cells is reviewed. The major problems associated with probe diagnostics in a GEC cell are outlined and discussed. While the data base is still insufficient to give definitive values for many parameters, a number of standard measurements are put forward. The plasma density in argon is 9×10⁹ cm⁻³ (±20 %) at an applied rf voltage of 250 V (500 V peak to peak) and a gas pressure of 13.3 Pa (100 mTorr). The electron density scales linearly with applied voltage. The plasma to ground sheath resistance is shown to be very important with a value of 810 Ω in argon at a pressure of 13.3 Pa (100 mTorr) and discharge current of 0.1 A. The value of plasma to ground resistance scales inversely with discharge current and sublinear with pressure. Two standard features in the electron energy distribution function (EEDF) have been proposed as a test of the ability of a probe system to resolve features, first, the transition from a low temperature (<1 eV) bi-Maxwellian distribution to a Druyveysten distribution (3 eV) at 13.3 Pa (100 mTorr) in argon, and the “hole” in the EEDF at 2 eV to 4 eV in nitrogen plasmas.     

利用朗缪尔双探针诊断电弧离子镀等离子体参数

本文利用朗缪尔双探针对电弧离子镀等离子体进行了诊断.双探针具有收集电流小的优点(小于离子饱和电流),可以避免探针在高密度电弧离子镀等离子体中被烧坏.利用离散傅里叶变换(DFT)对测量曲线进行平滑,有效地克服了电弧离子镀等离子体放电所固有的强烈波动.探针端部设计能够避免由薄膜沉积造成的探针与支撑杆短路问题.实验结果表明,等离子体密度随着弧电流和气压的增加而增加,而电子温度随着弧电流和气压变化不明显.另外,使用双靶放电等离子体密度和电子温度高于单靶放电.这些结果提供了电弧离子镀等离子体的基本参数,对于材料涂层工艺研究具有积极意义.     

Probe Diagnostics of Dusty Plasma

The model of multiply charged heavy ions is used to investigate the effect of aerosol particles on the readings of a spherical probe in a quiescent collisional plasma under the condition of a thin sheath.