感应耦合等离子体刻蚀机二维放电模拟

为研究感应耦合等离子体(ICP)刻蚀机腔室与线圈结构以及工艺参数对等离子体分布均匀性的影响,基于商业软件CFD-ACE+中等离子体与电磁场等模块建立了ICP刻蚀机二维放电模型.仿真研究了典型工艺条件(1.33Pa,200W,200sccm)下氩等离子体电子温度与电子数密度的空间分布,对比了不同气压与功率条件下等离子体参数在硅片表面的一维分布.结果表明,电子数密度随气压与功率的增加而升高;电子温度随气压的增加而降低,随功率增加在较小范围内先降低再升高.通过分析屏蔽板对等离子体参数的影响,发现其有助于提高等离子体密度.进而发现屏蔽板的孔隙率越大,电子温度越高,电子数密度则越低.     

感应耦合等离子体刻蚀机二维放电模拟

为研究感应耦合等离子体(ICP)刻蚀机腔室与线圈结构以及工艺参数对等离子体分布均匀性的影响,基于商业软件CFD-ACE 中等离子体与电磁场等模块建立了ICP刻蚀机二维放电模型.仿真研究了典型工艺条件(1.33Pa,200W,200sccm)下氩等离子体电子温度与电子数密度的空间分布,对比了不同气压与功率条件下等离子体参数在硅片表面的一维分布.结果表明,电子数密度随气压与功率的增加而升高;电子温度随气压的增加而降低,随功率增加在较小范围内先降低再升高.通过分析屏蔽板对等离子体参数的影响,发现其有助于提高等离子体密度.进而发现屏蔽板的孔隙率越大,电子温度越高,电子数密度则越低.     

超薄基区SiGe HBT基区渡越时间能量传输模型

通过求解玻尔兹曼能量平衡方程，得出基区的电子温度分布，建立了考虑电子温度变化，适用于超薄基区SiGeHBT的基区渡越时间模型。该模型考虑了电子温度对迁移率的影响，基区重掺杂和Ge引起的禁带变窄效应及速度饱和效应。比较了用能量传模型与漂移扩散模型计算的截止频率，利用器件模拟软件ATLAS进行了模拟，结果与能量传输模型计算结果吻合。     

放电泵浦F2分子激光器的等离子体特性

通过求解电子能量分布各向同性稳态破尔兹曼方程,获得放电泵浦F2分子激光器的等离子体的电子能量分布、各种反应速率系数,有助于了解F2分子激光形成机制。     

ECR等离子体沉积系统中等离子体特性的模拟

本文建立了一个物理模型，编写了数值程序，模拟了微波电子回旋共振（ＥＣＲ）等离子体流的特性。假定等离子体中的电子服从玻尔兹曼关系，离子在从共振区流向衬底的过程中与中性气体发生电荷交换和弹性碰撞。根据等离子体区应满足的电荷准中性条件，采用蒙特卡罗方法可计算出自恰的等离子体电位及离子密度分布。从而分析了磁场形态和气压对等离子体密度空间分布，入射到衬底上的离子通量和平均能量的影响，结果表明：磁场形态和气压都可用来独立控制等离子体流的性能，这对于使用该种等离子体源进行薄膜沉积和刻蚀有一定的理论指导意义。     

Mo和Ta的有效电子能量损失函数

在用Monte Carlo方法模拟电子与物质相互作用过程时，常用Mott截面描述电子与原子的弹性碰撞，而用介电函数理论描述电子的非弹性散射。Penn利用光学能量损失函数Im{-1／ε（q=0，ω）}外推法获得了描述动量转移不为零的能量损失函数Im{-1／ε（q，ω）}。该介电函数主要描述由于体激发而引起的能量损失，但当入射电子能量降低，或电子掠入、出射时，电子在表面区域会引起较强的表面电子激发模式，在电子能量损失谱中对应特征的能量损失，如表面等离子体激元峰，故常用的光学能量损失函数不适于描述电子的表面激发行为。     

ICP源MOSFET射频振荡器

介绍了ICP（感应耦合等离子体）C类射频振荡器的设计和调试结果.低温等离子体的应用已经非常广泛.以感应耦合方式将射频能量送入中性气体中激发等离子体,已经成为重要的等离子体源类型之一.传统的功率射频发生器大多使用电子管,体积大,也比较笨重.在射频发生器和等离子体装置之间需要设置射频传输线和匹配箱.以MOSFET代替传统的电子管作为有源器件组成的振荡器,体积很小,可以与等离子体源直接连接,省去了射频传输线和传输线终端的匹配箱.振荡器的频率为13.56 MHz,输出功率为200 W.试验结果达到了设计要求.     

单基扳彩色AC-PDP放电单元的二维数值模拟

介绍了基于粒子流运动连续方程建立的二维单基板彩色AC-PDP放电单元的数值计算模型。该模型包括混合气体中的电子、离子、激发态分子等15种基本粒子,描述粒子的反应、迁移和扩散过程。通过模拟单基板彩色AC-PDP放电单元的工作情形,给出了单元内电位、电子和离子浓度的分布情况。     

基于化学物质释放的五点傅里叶变换求解泊松方程的方法

在电离层化学物质释放数值模拟中,傅里叶变换是一种有效的求解泊松方程的方法,但其仿真精度有待进一步提高.文章提出一种改进的傅里叶变换求解泊松方程的方法,对泊松方程的五点差分形式做傅里叶变换,并引入误差修正项,弥补二阶差分带来的误差,模型中给出了详细推导过程,并与常用方法进行了对比分析.研究结果表明,改进方法求得电势的均方误差（Mean Square Error,MSE）相对Birdsall方法和电势求导方法小6个量级,电势空间分布更加接近解析结果.文中所提方法满足化学物质释放数值仿真的要求,为等离子体粒子模拟中泊松方程的求解提供了一种新的方法.     

基于电感耦合氧等离子体金刚石膜表面修饰的功率优化

采用电感耦合等离子体（ICP）氧等离子体刻蚀金刚石膜,探寻金刚石膜表面处理的方法。通过分析不同ICP射频源功率和不同偏压源功率下的刻蚀速率,研究了金刚石膜刻蚀的机理作用;通过拉曼光谱进行表征,分析刻蚀前后sp2与sp3的含量。结果表明,在ICP氧等离子体刻蚀的过程中,sp3键部分转化为sp2键;刻蚀后表面粗糙度降低;当...     

Mode Theory of Waveguide Filled with Warm Uniaxial Plasma

Characteristics of wave propagation in a guide filled with uniaxial anisotropic warm plasma are investigated. Basic equations of the plasma are derived. The validity of the plasma model and its physical significance are discussed. It has been found that TE modes are not affected by the presence of plasma. However, TM modes do have significant changes. Under the condition specified, each TM mode splits into two submodes. One has a low-frequency cutoff and the other propagates for all frequencies. The nature of power transfer in these modes is also investigated. A comparison of the effects as well as the physical significance of the changes due to cold and warm uniaxial plasma models are discussed.     

Fluid model of inductively coupled plasma etcher based on COMSOL

Fluid dynamic models are generally appropriate for the investigation of inductively coupled plasmas. A commercial ICP etcher filled with argon plasma is simulated in this study. The simulation is based on a multiphysical software, COMSOLTM, which is a partial differential equation solver. Just as with other plasma fluid models, there are drift-diffusion approximations for ions, the quasi-neutrality assumption for electrons movements, reduced Maxwell equations for electromagnetic fields, electron energy equations for electron temperatures and the Navier-Stokes equa-tion for neutral background gas. The two-dimensional distribution of plasma parameters are shown at 200 W of power and 1.33 Pa (10 mTorr) of pressure. Then the profile comparison of the electron number density and temperature with respect to power is illustrated. Finally we believe that there might be some disagreement between the predicted values and the real ones, and the reasons for this difference would be the Maxwellian eedf assumption and the lack of the cross sections of collisions and the reaction rates.     

Quantitative criteria for choosing models of the electron dynamics of the axially symmetric self-consistent motion of charged plasma in a magnetic field

Quantitative criteria for choosing models of the dynamics of beam electrons in the form of a cylinder expanding in plasma and vacuum are obtained on the basis of equations of axially symmetric self-consistent motion.     

Nonlinear electromagnetic theory of low-frequency instability of a relativistic electron beam in plasma with strongly nonpotential plasma and beam waves

A substantially nonpotential nonlinear theory of instability of a straight high-current relativistic electron beam propagating in a plasma waveguide under the conditions of the collective stimulated Cherenkov effect is elaborated. In the most general statement of problem, relativistic nonlinear equations for the temporal dynamics of this instability are obtained. The case of a low-density plasma is considered when both the plasma and beam waves are essentially nonpotential. Under the assumption that weak resonance plasma-beam interaction and linearity of plasma electrons are present, the general equations are transformed (by expanding the electron trajectories and momenta) to cubically nonlinear relativistic equations, which describe nonlinear shifts in frequencies of the plasma and beam waves. Analytic solutions to these equations are obtained with allowance for the dependence of the electron mass on the electron velocity and for the nonpotentiality of the interacting waves. The results are in good agreement with the numerical solutions of the general nonlinear equations in a wide range of values for the parameters.     

Study of the TRIM transistor

TRIM Devices can be classified as plasma-operated structures. This paper considers this possibility and forms a theoretical model which takes into account the effects of high level injection and punch through operation. It offers a simple cylindrical model for the purpose of analysis and compares its results with those of a computer simulated one-dimensional model, which can be used with any plasma operated device. The 1-D model uses the general transport equations to form a set of differential equations which can be integrated by an iterative method. The results achieved from these models are then compared with those obtained experimentally.     

填充环形等离子体的介质切伦可夫脉塞

利用线性场理论,对填充环形等离子体的介质切伦可夫脉塞进行了详尽的分析;讨论了薄环形相对论电子注包围环形等离子体、处于环形等离子体之间和位于环形等离子体之内,这三种情况下的注波互作用,分别导出了其色散方程;并对色散方程直接进行了数值求解;求得了系统的截止频率、工作频率和波增长率,讨论了有关参数对它们的影响。     

Method of extended bicharacteristic system in simulating wave propagation in ionospheric plasma

A procedure for studying wave propagation in ionospheric plasma based on the use of a bicharacteristic system and an extended bicharacteristic system of equations that allows the caustic structure to be determined has been developed. Propagation of an ordinary and extraordinary waves in an anisotropic plasma, in a one-layer and two-layer models, in the presence of local irregularities, has been numerically simulated. With the use of the radiotomography data, the effect of the equatorial anomaly on the propagation of decameter waves has been investigated.     

An E-J Collocated 3-D FDTD Model of Electromagnetic Wave Propagation in Magnetized Cold Plasma

A new three-dimensional finite-difference time-domain (FDTD) numerical model is proposed herein to simulate electromagnetic wave propagation in an anisotropic magnetized cold plasma medium. Plasma effects contributed by electrons, positive, and negative ions are considered in this model. The current density vectors are collocated at the positions of the electric field vectors, and the complete FDTD algorithm consists of three regular updating equations for the magnetic field intensity components, as well as 12 tightly coupled differential equations for updating the electric field components and current densities. This model has the capability to simulate wave behavior in magnetized cold plasma for an applied magnetic field with arbitrary direction and magnitude. We validate the FDTD algorithm by calculating Faraday rotation of a linearly polarized plane wave. Additional numerical examples of electromagnetic wave propagation in plasma are also provided, all of which demonstrate very good agreement with plasma theory.      

Kinetic theory of electromagnetic waves obliquely incident upon a plasma slab

The problem of an electromagnetic wave obliquely incident upon a plasma slab is considered as a boundary-value problem, using a self-consistent solution of the coupled linearized Vlasov and Maxwell equations for the electrons, with the ions treated as a fixed, uniform background. Power reflection, transmission, and absorption coefficients are derived under the assumption that electrons undergo specular reflection at the surfaces of the plasma slab. Although our analysis is valid for arbitrary slab thickness, computational results are presented for slabs which are thin compared to a free-space wavelength. The results show a series of resonances which are attributed to the kinetic behavior of the plasma. The results further show that the resonances are Landau damped as the thermal velocity of the plasma electrons increases. While similar resonances can be predicted from the coupled linearized hydrodynamic Maxwell equations, such a model does not predict Landau damping. The effects of a finite collision frequency are then included via a simple Bhatnager-Gross-Krook collision term. The numerical computations vividly indicate that the resonances undergo severe damping for extremely small ratios of the collision frequency to signal frequency.     

Laser metal interaction in vacuum

We investigate the processes by which energy is exchanged when a laser pulse is incident on a metal surface, originally in vacuum. The thermal state of the metal is determined by numerical solution of the nonlinear heat transfer equations. A method is described for extrapolating data on material thermal properties which are usually given at lower temperatures. Results are compared with the predictions of a steady-state calculation. Kinetic equations describing the growth of a plasma in the ablated vapor are formulated to describe effects of importance in the early stages of the plasma evolution process, when strong longitudinal spatial gradients cause thermal diffusion effects to dominate hydrodynamic expansion. Numerical studies of these equations indicate several distinct periods, during each of which a different physical mechanism takes on primary importance. Features of the numerical results pertaining to the propagation of the discharge front are deduced from an analytic model of the breakdown process.