Molecular Nitrogen Vibrational Temperature in an Inductively Coupled Plasma

Using a technique applied previously to vibrationally excited molecular nitrogen (N2^*) in the region of daytime and nighttime aurora,the emission intensity of the N2 second positive band system in an inductively coupled plasma (ICP) has been analysed and the vibrational temperature of nitrogen molecules in the ICP is thus determined.The result shows that the vibrational temperature increases with the increase of the neutral gas pressure from 0.04Pa to 10Pa,then decreases with the further increase of the pressure from 10Pa to 100Pa.Also,this is explained by using the Boltzmann relation between the vibrational temperature and the concentration of the vibrationally excited N2^*(X^1Σg^ ) molecules.     

Influence of External Magnetic Field on Anomalous Skin Effects in Inductively Coupled Plasmas

Using a one-dimensional slab model, we study the influence of the external static magnetic field on the anomalous skin effects in the inductively coupled plasma. The rf electromagnetic field in the plasma is determined by solving the linearized Boltzmann equation incorporating with the Maxwell equations. The numerical results show that,due to the existence of the external magnetic field, the anomalous skin effects are greatly enhanced and the number of regions with negative absorption is decreased.     

Tuning Effect on the Electron Energy Distribution Function of an Inert Gas Mixture in nitrogen Inductively Coupled Plasma Discharges

By using a Langmuir probe, the electron energy distribution function (EEDF) is measured in inductively coupled plasma discharges in N2/Ar mixtures at 200W rf powers. In pure N2 discharges a Maxwellian EEDF is observed.When the mixing ratio of Ar increases, the distribution of high-energy electrons evolves with a different trend from that of low-energy electrons, resulting in an apparent “two temperature structure” of the EEDF. We discuss this non-Maxwellian EEDF and its effect on the measurement and the interpretation of “electron temperature”by both the probe and line ratio technique.     

Electromagnetic Instabilities Excited by Electron Temperature Anisotropy

One-dimensional particle-in-cell simulations are performed to investigate the nonlinear evolution of electromagnetic instabilities excited by the electron temperature anisotropy in homogeneous plasmas with different parameters. The results show that the electron temperature anisotropy can excite the two right-hand electromagnetic instabilities, one has the frequency higher than Ωe, the other is the whistler instability with larger amplitude, and its frequency is below Ωe. Their dispersion relations are consistent with the prediction from the cold plasma theory. In the initial growth stage (prediction from linear theory), the frequency of the dominant mode (the mode whose amplitude is large enough) of the whistler wave almost does not change, but in the saturation stage the situation is different. In the case that the ratio of electron plasma frequency to cyclotron frequency is larger than 1, the frequency of the dominant mode of the whistler wave driRs from high to low continuously. However, for the case of the ratio smaller than 1, besides the original dominant mode of the whistler wave whose frequency is about 2.6ωe, another dominant mode whose frequency is about 1.55ωe also begins to be excited at definite time, and its amplitude increases with time until it exceeds the original dominant mode.     

Comparative Study on Excitation Mechanism of Chromium Emission Lines in Argon Radio‐Frequency Inductively‐Coupled Plasma,Nitrogen Microwave Induced Plasma,and Argon or Nitrogen Glow Discharge Plasmas

Boltzmann plots of both atomic and ionic chromium emission lines are investigated to compare the excitation mechanisms in four different plasmas: an argon inductively‐coupled plasma (Ar‐ICP), a nitrogen high‐power microwave induced plasma (N₂‐MIP), an argon glow discharge plasma (Ar‐GDP), and a nitrogen glow discharge plasma (N₂‐GDP). The plots of the atomic lines and the ionic lines give both linear relationships as well as similar excitation temperatures in the case of the Ar‐ICP, the N₂‐MIP, and the N₂‐GDP. It implies that a thermodynamic process such as electron collision would control their excitations. However, only in the case of the ionic‐line plot in the Ar‐GDP, a departure from linear relationship is observed and the estimated excitation temperature is rather higher than that with the atomic lines, meaning that a specific excitation mechanism exists in the Ar‐GDP. A possible explanation for these results is that a charge‐transfer collision between chromium atom and argon ion plays a dominant role in exciting highly‐lying energy levels of chromium ion, especially in the Ar‐GDP.     

Electron Temperature Gradient Driven Instability in High Beta Plasmas of a Sheared Slab

Neglecting the magnetic gradient drift effects, we derive a simplified version of the integral eigenvalue equations for perturbations of electrostatic potential, and the perpendicular and parallel components of magnetic vector potential in plasmas of sheared slab geometry. The electron temperature gradient (ETG) instability in high beta plasmas is studied with the equations and the corresponding computer code. The preliminary results indicate that the coupling to perturbation of the perpendicular component of the magnetic vector potential has strong destabilization effects on ETG instabilities in contrast to the stabilization effects from the coupling to that of the parallel component when the magnetic gradient drift is not taken into account.     

Identification of Three Weak Lines and Their Influences on Diagnostics of Electron Temperature and Density in Astrophysical Plasmas

By comparing of the spectra from the Chandra LETGs observation with the synthetic spectra of argon, we identify two weak emission lines, that is, the Ar XV 27.470A line with transition 2s3p ^1p1 - 2s^2 ^1So and the Ar XVI 27.872A line with transition 3d ^2D3/2 - 2p ^2P1/2, which blend with the N Ⅶ Lyα emission line. Several secondorder spectral lines are also identified, one of which is the second-order Fe XⅧ 14.534A line with transition 2p^4(^3p)3d ^2F5/2 - 2p^5 ^2P3/2, which blends with the inter-combination line of He-like N VI. In order to study the effects of these new identified weak lines on the electron temperature and density, we diagnose the two parameters using the intensity ratio of triplets of the He-like N Ⅵ and that of resonance lines of H- and He-like N. In the literature, there is a discrepancy of the temperatures deduced from N Ⅵ from other He-like ions, such as C V and O Ⅶ. The discrepancy disappears after the contribution of these weak lines is taken into account.     

A New Kinetic Mode Driven by Electron Temperature Gradient

A new unstable short wavelength mode is identified in sheared slab plasmas using a fully kinetic integral equation code. This mode is driven by the electron temperature gradient and propagates in the ion diamagnetic direction. The instability occurs due to the electron inverse Landau damping effect at short cross-field wavelength regions.     

Study of Electron Temperature Gradient Instability in Toroidal Plasmas with Negative Magnetic Shear

In this paper, the electron temperature gradient （ETG） instability and corresponding turbulent transport in toroidal plasmas with negative magnetic shear is studied using the integral eigenvalue equations. The full electron kinetics is considered and the behaviours of the modes and the transport in the parameter regimes close to the instability threshold are emphasized. The fitting formulas of the critical gradient, for negative magnetic shear, are given.     

Vertical and Smooth, etching of InP by Cl2／CH4／Ar Inductively Coupled Plasma at Room Temperature

We study the room-temperature dry, etching of InP by inductively coupled plasma (ICP) using C12/CH4/Ar mixtures. Etches were characterized in terms of anisotropy and surface roughness by scanning electron microscopy and atomic force microscopy, respectively. It is found that the flow ratio between C12 and Ctt4, ICP power, rf chuck power, and table temperature can greatly influence the, etching results. By adjusting, etching parameters,vertical sidewall and smooth surface can be obtained simultaneously, together with a moderate, etch rate and a good select ratio. The root-mean-square surface roughness is measured to be as low as 0.27nm. To the best of our knowledge, this is the best result for InP to date. The, etch rate is 855nm/min, and the selectivity ratio overSi02 is estimated to be higher than 15:1. The stoichiometry of the, etched surface has also been investigated by Auger electron spectroscopy. The, etched surface is found to manifest a slight P deficiency, and the ratio between P and In reaches the stoichiometric value within about 0.75nm depth into the surface.     

Al-Induced Crystallization Growth of Si Films by Inductively Coupled Plasma Chemical Vapour Deposition

Polycrystalline Si （poly-Si） films are in situ grown on Al-coated glass substrates by inductively coupled plasma chemical vapour deposition at a temperature as low as 350℃. Compared to the traditional annealing crystalliza- tion of amorphous Si/Al-layer structures, no layer exchange is observed and the resultant poly-Si film is much thicker than Al layer. By analysing the depth profiles of the elemental composition, no remains of A1 atoms are detected in Si layer within the limit （〈0.01 at.%） of the used evaluations. It is indicated that the poly-Si material obtained by Al-induced crystallization growth has more potential applications than that prepared by annealing the amorphous Si/Al-layer structures.     

Instability and Transport Driven by an Electron Temperature Gradient Close to Critical

Recent observations on tokamaks have shown that, within internal transport barriers (ITBs), electron thermal transport hardly changes while ion thermal diffusivity is reduced to the neoclassical level. These findings support the hypothesis that, within an     

AlGaN/GaN HEMTs with an Insulated Gate Fabricated by Inductively Coupled Plasma Oxidization

Novel AlGaN/GaN high electron mobility transistors （HEMTs） with an insulated gate have been demonstrated by oxidizing the surface of an AlGaN layer using inductively coupled O2 plasma. X-ray photoelectron spectroscopy measurement reveals that O2 plasma treatment can produce a thin oxidized layer on the AlGaN surface. The insulated-gate devices are realized by plasma oxidization before gate metallization. The reverse gate leakage current of the fabricated HEMT has been reduced in two orders of magnitude, and the cut-off frequency increases from 5.4 GHz to 6.5 GHz.     

Relaxation of Dense Electron Plasma Induced by Femtosecond Laser in Dielectric Materials

Electron plasma induced by a focused femtosecond pulse （130 fs, 800 nm） in dielectric materials （Soda Lime glass, K9 glass, and SiO2 crystal） is investigated by pump-probe shadow imaging technology. The relaxation of the electron plasma in the conduction band is discussed. In SiO2 crystals, a fast self-trapping process with a trapping time of 150fs is observed, which is similar to that in fused silica. However, in Soda Lime glass and K9 glass, no self-trapping occurs, and two decay processes are found： one is the energy relaxation process of conduction electrons within several picoseconds, another is an electron-hole recombination process with a timescale of lOOps. The electron collision time T in the conduction band is also measured to be in the order of 1 fs in all of these materials.     

Helium—Charged Titanium Films Deposited by Pulsed Laser Deposition in an Electron—Cyclotron—Resonance helium Plasma Environment

Titanium thin films incorporated with helium are produced by pulsed laser deposition in an electron cyclotron resonance helium plasma environment.Helium is distributed evenly in the film and a relatively high He/Ti atomic ration(-20%) is obtained from the proton backscattering spectroscopy.This high concentration of helium leads to a surface blistering which is observed by scanning electron microsocopy.Laser repetition rate little influence on film characters.Substrate bias voltage is also changed for the helium incorporating mechanism study,and this is a helium ion implantation process during the film growth.Choosing suitable substrate bias voltage,one can avoid the damage produced by ion implantation,which is always present in general implantation case.     

Temperature—Induced Magnetization Reorientation in GdFeCo／TbFeCo Exchange—Coupled Double Layer Films

GdFeCo/TbFeCo exchange-coupled double-layer (ECDL) films used /or centre aperture type magnetically in-duced super resolution were investigated through experiments and theoretical calculation. The ECDL films were prepared by the magnetron sputtering method. Polar Kerr effect measurements showed that magnetization reorientation occurred in the GdFeCo layer with the temperature rising, which was subsequently analysed by the micromagnetic calculation based on the mean-field theory and a continuum model. Theoretical analysis is in agreement well with the experimental results.     

Electron Transport Property of CdTe under High Pressure and Moderate Temperature by In-Situ Resistivity Measurement in Diamond Anvil Cell

In situ resistivity measurement has been performed to investigate the electron transport property of powered CdTe under high pressure and moderate temperature in a designed diamond anvil cell. Several abnormal resistivity changes can be found at room temperature when the pressure increases from ambient to 33 GPa. The abnormal resistivity changes at about 3.8 GPa and 10 GPa are caused by the structural phase transitions to the rock-salt phase and to the Cmcm phase, respectively. The other abnormal resistivity changes at about 6.5 GPa, 15.5 GPa, 22.2 GPa and about 30 GPa never observed before are due to the electronic phase transitions of CdTe. The origin of the abnormal change occurred at about 6.5 GPa is discussed. The temperature dependence of the resistivity of CdTe shows its semiconducting behaviour at least before 11.3 GPa.     

Electron Injection by E—Field Drift and its Application in Starting—up Tokamaks at Low Loop Voltage

We propose an innovative method of election injection by E-field drift into a plasma device and discuss its application in starting-up tokamak plasmas at low loop voltage.The experimental results obtained from HT-6M Tokamak are also presented.The breakdown loop voltage is obviously reduced and the discharge performance is improved by using the electron injection method.It could be applied to some other types of plasma device.     

Storage of Photoexcited Electron—Hole Pairs in an AlAs／GaAs Heterostructure Created by Electron Transfer in Real and κ Spaces

The storage of photoexcited electron-hole pairs is experimentally carried out and theoretically realized by transferring electrons in both real and κ spaces through resonant Γ-X in and AlAs/GaAs heterostructure,This is proven by the peculiar capacitance jump and hysteresis in the measured capacitance-voltage curves.Our structure may be used as a photonic memory cell with a long storage time and a fast retrieval of photons as well.