等离子体刻蚀工艺中的光学发射光谱仪数据的模型研究(英文)

原位光学发射光谱仪(OES)已经成为等离子体刻蚀工艺控制过程中的一种非常有潜力的在线传感器系统。采用光谱仪实时采集高密度等离子体刻蚀机中的OES光谱数据,利用BP神经网络算法对特定波长的OES数据进行分析及建模,以便对等离子体刻蚀工艺过程进行反馈控制。由刻蚀产物SiCl发出的405nm谱线被选为特征谱线来确定刻蚀工艺过程的终点。     

Delayed hot spots in a low energy plasma focus

In a low energy Mather-type plasma focus device, hot spots having temperature in the range of few KeV have been observed even 1 μs after the pinch disintegration and in regions away from the pinch area. These hot spots are perhaps created by the thermal runway due to temperature fluctuations in the background gas.     

Numerical study of chaotic oscillations in the electron beam with virtual cathode in the external non-uniform magnetic fields

In this Letter the results of theoretical investigations of the chaotic microwave oscillator based on the electron beam with a virtual cathode are presented. Nonlinear non-stationary processes in these electron systems are studied by means of numerical analysis of 2.5D model. It was discovered that the non-uniform external magnetic field value controls the dynamical regime of oscillations in the virtual cathode oscillator. The processes of the chaotization of output microwave radiation are described and interpreted from the point of view of the formation and interaction of electron structures (bunches) in the electron beams. The numerical results have shown that the investigated electron system with virtual cathode could be considered as a promising controlled source of wideband chaotic oscillations in the microwave range.     

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利用朗缪尔探针和发射光谱两种诊断手段,测量了某固体工质等离子体发生器的喷流流场参数。结果表明,在输入功率为2kW时,发生器可持续稳定工作300s;发生器燃烧室内最高温度为800K。稳定工作时,发生器壳体结构正常,没有发现损毁现象;等离子体喷流的电子密度为1011～1012cm–3量级,电子温度为1.5～3.5eV。     

金刚石簿膜淀积过程中微波等离子体特性

一、引言 在金刚石薄膜的制备过程中,人们往往监测成膜过程中的宏观参量,使其工艺的重复性,优选性受到了很大限制。而随着对膜质量和结构的要求越来越高,人们开始开展对低压下合成金刚石机理的研究,但至今未见系统地研究宏观参量与等离子体参量方面的工作报道。     

微波共振探针及其在等离子体诊断中的应用

介绍了能够测量稳定和时变等离子体电子密度的微波共振探针,给出了其工作原理和在测量稳定、时变和瞬态等离子体电子密度中的应用。分析了传输模式和反射模式的工作过程及对测量范围、测量精度和空间分辨率等影响因素。结果表明,选用较长的探针有利于提高电子密度的测量范围和精度;选用的微波扫频源高端频率越高,频率分辨率越高,则电子密度的测量范围越大,测量精度越高。理论分析得出系统可测量的电子密度约为1.37×10⁸~4.1×10¹¹cm^-3。     

Charged-particle distribution in velocity,angle and time by Fokker-Planck equation

Summary The present paper describes a direct method of obtaining are expression of the distribution function of charged particles which diffuse in a plasma. The distribution function in velocity, angle and time is presented starting from the Fokker-Planck equation. Temperature, average velocity and energy of charged particles (electron or ions) have also been calculated as functions of time. The authors of this paper have agreed to not receive the proofs for correction.     

Evolution equations of the expected phase space ion densities and correlation functions in a D+T plasma

Summary In this paper we formualte a master equation approach describing a D+T thermonuclear plasma in a lumped phase space. From the first moments of this master equation and performing the pass to the continuous limit the evolution equations for the expected phase space ion densities emerge. Also we have obtained the evolution equations of the equal time correlation and covariance functions. Finally we have deduced the hydrodynamic equations that arise from a master equation approach.     

Thermal behavior and catalytic activity in naphthalene destruction of Ce-, Zr- and Mn-containing oxide layers on titanium

The present paper is devoted to studies of the composition and surface structure, including those after annealing at high temperatures, and catalytic activity in the reaction of naphthalene destruction of Ce-, Zr- and Mn-containing oxide layers on titanium obtained by means of the plasma electrolytic oxidation (PEO) method. The composition and structure of the obtained systems were investigated using the methods of X-ray phase and energy dispersive analysis and scanning electron microscopy (SEM). It was demonstrated that Ce- and Zr- containing structures had relatively high thermal stability: their element and phase compositions and surface structure underwent virtually no changes after annealing in the temperature range 600-800 °C. Annealing of Ce- and Zr-containing coatings in the temperature range 850-900 °C resulted in substantial changes of their surface composition and structure: a relatively homogeneous and porous surface becomes coated by large pole-like crystals. The catalytic studies showed rather high activity of Ce- and Zr-containing coatings in the reaction of naphthalene destruction at temperatures up to 850 °C. Mn-containing structures of the type MnO_x + SiO₂ + TiO₂/Ti have a well-developed surface coated by “nano-whiskers”. The phase composition and surface structure of manganese-containing layers changes dramatically in the course of thermal treatment. After annealing above 600 °C nano-whiskers vanish with formation of molten structures on the surface. The Mn-containing oxide systems demonstrated lower conversion degrees than the Ce- and Zr-containing coatings, which can be attributed to substantial surface modification and formation of molten manganese silicates at high temperatures.     

快速真空紫外光谱诊断在EAST实验的初步应用

为了在EAST装置上开展高参数放电条件下边界杂质辐射的实验研究,发展了真空紫外(VUV)光谱诊断系统.该系统采用了焦距为200mm的Seya-Namioka型VUV光谱仪,并配备了600g·mm-1凹面全息光栅,所能观测的波长范围为50～700nm,覆盖真空紫外、近紫外和可见光波段.系统在垂直方向的观测范围为Z=-35...     

Dielectric parameterization of raman lineshapes for GaP with a plasma of charge carriers

We have studied the Raman lineshapes of several samples of GaP with appreciable carrier concentrations. There is no feature identifiable as a plasma resonance, but there are pronounced effects of interaction with the LO phonon resonance. For analysis we have developed a model along lines laid down by Barker and Loudon, employing Nyquist relations to calculate infrared fluctuations which scatter light. We introduce a response matrix α(ω) withseveral resonances; and we uncover some points which seem to be new, for coupled-mode scattering systems in general. In the GaP-plasma problem the data do not necessitate inclusion of the scattering amplitude from the plasma; we ascribe this to large plasma damping rates (ωτ≲1). This provides an account for the lack of any apparent plasma resonance in the scattering and for the modified appearance of the LO phonon, relative to the pure crystal. We emphasize that the following parameters suffice: Lorentz parameters measured in linear infrared experiments, the nonlinear parameterC from a visible-infrared mixing experiment, and the plasma frequency and damping fit to each sample. Beyond treatment of the plasma problem, the theory bears more generally on the conditions under which an LO Raman lineshape measures locally the shape of 〈E ²〉_ω. Also it bears upon the analysis of polariton linewidths to infer the variation of the phonon damping Γ(ω). This work was supported by the National Science Foundation Grant No. GH 32401. It is based on a major segment of the thesis of D.T. Hon, submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Physics) in the Faculty of the Graduate School of the University of Southern California.     

The influence of electrode gap width on plasma properties of diffuse coplanar surface barrier discharge in nitrogen

In this work we have studied the influence of electrode gap width (inter-electrode distance) on plasma properties of the diffuse coplanar surface barrier discharge. The outer conditions and discharge configuration can substantially influence properties of the discharge. Better understanding of these effects can lead to optimization of the discharge parameters for industrial applications. In this work the discharge was operated in nitrogen at atmospheric pressure. The electrode gap width was varied in the range from 0.6 to 2.2 mm. The input voltage, electrode temperature and gas flow was kept constant for all cases. Plasma parameters were studied by the means of time and space resolved optical emission spectroscopy and oscilloscopic measurements. These measurements gave us time and space distribution of discharge luminosity (e.g. intensities of second positive and first negative systems of nitrogen) and 1D-spatial profiles of rotational and vibrational temperature of nitrogen.     

Millimeter and Submillimeter Wave ESR System: Using 30 T Pulsed Magnetic Field

New systems for millimeter and submillimeter wave ESR have been developed in Kobe University. In the previous system the pulsed magnetic field was limited up to 17 T in the temperature range from 1.8 to 86 K. Using the new systems, we can measure in the field range up to 30 T in the temperature range from 1.8 K to 4.2 K and from 18 K to room temperature. The resolution of the magnetic field has been also improved in the new ESR system. The details of our new ESR systems are presented. In addition, the measurements of Yb₂Cu₂O₅ using these new systems are presented.     

A study of balancing the competing effects of ultrashort laser induced plasma for optimal laser machining

We report that plasma generated during processing of materials with ultrashort pulse lasers and the associated high intensity optical beam have both favourable and unfavourable impact on the machined surface quality. Intensity of the optical beam propagating through ambient air medium enhanced further by self-focusing is sufficiently high to cause gas breakdown forming air plasma. The generated plasma reduces the effect of self-focusing but also distorts the beam profile. Duration of the pulse being too short for thermal equilibrium to establish, ablation occurs largely by direct removal of the material forming another plasma plume. Normally, the scattering effect of plasma results in distortions of the fabricated features. However, for certain parameter ranges, the competing self-focusing and gas plasma plumes supplemented with the material plasma can combine to cause filamentation, eliminating the distortions. Filament of hot plasma also acts as a well-shaped energy source. In the present study, brass is taken as an example for the investigation. Experiments were conducted to capture the spectrum of the light scattered by plasma using a spectrometer. Analysis was done to estimate the material plasma. Theoretical calculation on the intensity distribution in an optical beam propagating through air was then followed for a range of parameter values taking the self-focusing effect of the medium and the impact of the plasma generated by its breakdown. Approximate values of the machining parameters for clean fabrication are deduced from the calculations, which were used to conduct a laser machining test on brass.     

Plasma-aided hydrogenation and Al-doping: Increasing the conductivity and optical transparency of ZnO transparent conducting oxide

Plasma-assisted magnetron sputtering with varying ambient conditions has been utilised to deposit Al-doped ZnO (AZO) transparent conductive thin films directly onto a glass substrate at a low substrate temperature of 400 °C. The effects of hydrogen addition on electrical, optical and structural properties of the deposited AZO films have been investigated using X-ray diffractometry (XRD), scanning electron microscopy (SEM), Hall effect measurements and UV-vis optical transmission spectroscopy. The results indicate that hydrogen addition has a remarkable effect on the film transparency and conductivity with the greatest effects observed with a hydrogen flux of approximately 3 sccm. It has been demonstrated that the conductivity and the average transmittance in the visible range can increase simultaneously contrary to the effects observed by other authors. In addition, hydrogen incorporation further leads to the absorption edge shifting to a shorter wavelength due to the Burstein-Moss effect. These results are of particular relevance to the development of the next generation of optoelectronic and photovoltaic devices based on highly transparent conducting oxides with controllable electronic and optical properties.     

Quantum Theory of Solid State Plasma Dielectric Response

We review the quantum mechanical derivation of the random phase approximation (RPA) for solid state plasmas, starting from the Hamilton equations for canonically paired “second quantized” creation and annhilation field operators of interacting quantum many‐body systems. Discussing variational differentiation, the coupled equations of motion for the quantum field operators are derived. The concept of Green's functions is reviewed and interpreted, first for retarded Green's functions, and their equations of motion are developed from the equations of motion for the field operators. Thermodynamic Green's functions are discussed, and their periodicity/antiperiodicity properties in imaginary time are carefully examined with discussion of Matsubara Fourier series and representation in terms of a spectral weight function. The analytic continuation from imaginary time to real time is treated. Finally, we define nonequilibrium Green's functions and discuss the linearized timedependent Hartree approximation leading to the random phase approximation. An interesting application to the case of Graphene in a perpendicular magnetic field is discussed in detail, along with applications to normal systems, in terms of attendant phenomenology involving electron‐hole pair excitations and plasmons (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

CCD智能化光谱仪的研制

本文报道了一种新型的ＣＣＤ光谱仪的研制，包括三部分；即ＣＣＤ光探测器，光路系统，与计算机联接的控制和数据采集系统。该光谱仪的分辨率为０．０３５ｎｍ，灵敏光谱范围４００－９００ｎｍ。光谱仪操作简便，可对复杂光谱进行快速处理。已成功应用于低温等离子体的光谱诊断，获得了很好的测量结果。     

Multi-scale plasma simulation by the interlocking of magnetohydrodynamic model and particle-in-cell kinetic model

Many kinds of simulation models have been developed to understand the complex plasma systems. However, these simulation models have been separately performed because the fundamental assumption of each model is different and restricts the physical processes in each spatial and temporal scales. On the other hand, it is well known that the interactions among the multiple scales may play crucial roles in the plasma phenomena (e.g. magnetic reconnection, collisionless shock), where the kinetic processes in the micro-scale may interact with the global structure in the fluid dynamics. To take self-consistently into account such multi-scale phenomena, we have developed a new simulation model by directly interlocking the fluid simulation of the magnetohyrdodynamics (MHD) model and the kinetic simulation of the particle-in-cell (PIC) model. The PIC domain is embedded in a small part of MHD domain. The both simulations are performed simultaneously in each domain and the bounded data are frequently exchanged each other to keep the consistency between the models. We have applied our new interlocked simulation to Alfvén wave propagation problem as a benchmark test and confirmed that the waves can propagate smoothly through the boundaries of each domain.     

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给出了不同坐标系中介质参数张量的变换,得到了磁化冷等离子体球电场的表达式,得出了任意各向异性目标散射场的表达式,研究了磁化冷等离子体球的微分散射截面、散射截面等的函数关系,仿真结果与有关文献一致,表明了本算法的有效性,从而为各向异性目标识别等提供理论支持。     

波导等离子体限幅器中气体的选择与触发条件计算

 为保护电子设备不受高功率微波损坏,在矩形波导中嵌入等离子体限幅器。计算了不同气体的微波击穿场强随气体压强以及微波频率的变化规律。在高气压条件下（1 333~133 320 Pa）,气体击穿场强随气压增大而增大,在计算的4种气体中Ne的击穿场强最小;低气压条件下（1.333 2~133.32 Pa）,气体击穿场强随气压增大而减小,且Xe具有最小击穿场强。高气压条件下气体的击穿场强明显高于低气压下的击穿场强。计算结果表明：当填充133.32 Pa的Xe时,限幅器能够在约30 km范围内,有效地防护10 GW级高功率微波对电子设备的损坏。