We investigated the ion densities generated in CF₄ plasma, and developed a practical reaction model of CF₄ using PIC-MCC (Particle-in-Cell Monte Carlo Collision). A Langmuir probe and the quadrupole mass-spectra analyzer HAL EQP300 were connected to a 6-inch-size capacitively coupled plasma reactor for measuring the plasma parameter and the ion densities.
We measured the ion densities in CF4 plasma under the following conditions: RF power range from 50 to 150W, CF₄ gas flow rate 50 seem, and pressure range from 6.7 to 20Pa. In CF₄ plasma, CF₃⁺, CF₂⁺, CF⁺ were generated in the ratio of 1.0: 0.06: 0.04, which indicates CF₃⁺ is dominant. In our CF₄ plasma model, the generations of CF₃⁺ and CF₃ are considered mainly. We also justified our model by calculating the rate equation on CF₄ plasma.
The experimental results and simulation results show good agreements in the electron density, electron temperature, and plasma potential. In CF₄ plasma, as RF power increases, the densities of CF₃⁺ and CF₃ become larger. Simulation results indicate this dependency on RF power. Furthermore, we measured SiO2 etching rates at wafer center and wafer edge to estimate the ion spatial distribution. The distribution of etching rate is similar to CF₃⁺ ion flux distribution calculated from PIC-MCC simulation.
Plasma parameter, the dependency on FR power and pressure, and ion distribution are predicated in our practical plasma model of CF₄

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RF (13.56MHz) breakdown conditions of Ne-N₂ and Ar-N₂ mixtures are investigated in a parallel plate capacitively coupled device with varying the total pressure p, N₂ mix ratio and the electrode spacing L. In both mixtures, the dependence of the breakdown voltage V_B on p exhibits typical V-shaped curve in most mix ratios. As the mix ratio is increased, V_B in the right branch of V-shaped curve increases at a fixed p, strongly depending on p. Present numerical results show that the pressure dependence of the rate of increase of VB may be attributed to the difference in the dominant inelastic process, which has a great influence on the electron energy distribution related to the electron production. The similarity law and Penning effect are also studied in these mixtures. Experimental results show that the similarity law is virtually valid in the right branch where the amplitude of the periodic motion of electrons is small, and the decrease of V_B (Penning effect) is observed in a certain range of pL, which becomes narrow with the increase of the mix ratio.

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Spatially resolved steady state (SST) transport properties of electrons in Ne including the electron flux and the energy flow under a high reduced electric field E/N of 300 [Td] are investigated with the numerical data obtained by SST-FTI method. It is confirmed that the local net energy gain is always the same as the sum of the local energy loss and the divergence of energy flow. That is, the local conservation of energy and the continuity of energy flow are both explicitly verified. The features of SST and PT (pulsed Townsend) transport properties in conservative and non-conservative conditions for the electron number are also discussed.

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This paper describes the influence of initial energy distribution of the electron emitted from the cathode on the behavior of the electron swarm in a PDP cell. Spatial and temporal distributions of the electron transport coefficients are obtained with two types of the initial energy distribution of electrons at the cathode. The results for the electron transport coefficients in the equilibrium region almost agree, but large differences are found in the nonequilibrium region, particularly near the cathode. If the initial energy of emitted electron from the cathode is large, the transmitted electron through gas is decreased due to the increase of the back scattering and on the contrast the multiplication factor of the collisional ionization is increased.

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Behavior of the electron swarm at the starting condition of the self-sustaining discharge depending on p₀d is investigated in Ne and Ar by using a Monte Carlo Simulation (MCS). The calculations are performed under the E/p₀ and p₀d conditions including the Paschen minimum which was obtained from the experiment by Penning and Addink. From the result it is found that the energy non-equilibrium region spread over almost the gap space in particular near the Paschen minimum. So we proposed the improved description for the formula of Townsend's self-sustaining condition. The calculated results allows that the starting conditions of the self-sustained discharge in Ne and Ar would be applicable to the Engel's theory.

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A final purpose of this research is an efficient application of radicals, such as ozone, atomic oxygen and OH radical, for water purification. In our experiments, the radicals with short life-time were generated by a discharge occurred inside the bubbles in water. The bubbles generated by a bubbling tube were passed through a discharge region between the plate electrodes. The diameters of the bubbles generated by the bubbling tube were about 1.5mm and the bubbling gas was oxygen. The magnetic-pulse-compression pulsed-power generator was used as a repetitive power supply. In the experiments, the measurements of ozone concentration were carried out at various flow rates of the bubbling gas and repetition rates. The maximum ozone concentration of about 6.42g/Nm³ was obtained when the repetition rate of pulsed-power generator, the peak value of applied voltage, and the bubbling gas flow rate were 150pps (pulse per second), 22kV, and 0.3l/min, respectively. The discharge energy inside bubbles was obtained by an integration of the power calculated by multiplication of voltage by current. Using the discharge energy inside bubbles, ozone yield of about 64.2g/kWh was estimated.

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The authors have studied on reactions occurred in the processing of PTFE (Poly-Tetra-Fluoro-Ethylene) surfaces using high E/n discharge in nitrogen-rich condition. During the processing, the sample on the cathode was also irradiated by ions with kinetic energy of several 10 to several 100eV. And neutral active species such as metastables and nitrogen atoms generated in the discharge space reach the sample by diffusion process. Therefore, it is considered that the modification depth is different in the two cases.
In this report, to clarify the relative distributions in the modified layer of the PTFE, an XPS analysis on the sample was carried out using photoelectron take-off-angle resolution. Then, it was obtained that nitrogen density distribution has two peaks at shallow region and around several nm in the sample. Further, to know the kind of active species for contribution of the processing, these results were compared to the past results.
As a result, the following are considered. The distribution of nitrogen on the sample around shallow region was introduced by irradiation of neutral species such as metastables and nitrogen atoms. And, the distribution around several nm from the surface was introduced by ions with kinetic energy.

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The population density of Xe (1s₅) in a low frequency (476kHz) Xe/He discharge plasma, which is modulated "on" and "off", between barrier electrodes has been measured using a laser absorption spectroscopy. The modulation of the plasma provided high S/N (signal to noise ratio) signals, consequently the Xe (1s₅) density was measured down to 10⁷cm^-3. The spatial distribution of the Xe (1s₅) density in the gap was obtained. The maximum of the density appeared near the powered electrode, on the other hand, near the grounded electrode the Xe (1s₅) density was lower than that near the powered electrode.
Diffusion of Xe (1s₅) from the gap to the outside of the gap was seen.

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The characteristics of RF plasmas as a function of driving frequency f, 0.1-13.56MHz in nitrogen has been observed by optical emission spectroscopic method. The space- and time-resolved profiles of the net excitation rate of molecules and ions have been deduced from spatiotemporally resolved optical emission profiles of their species, i.e. the second positive and the first negative bands. It is found that ionizations due to the secondary electrons from the electrodes by positive ions play an important part in the maintaining mechanism at low frequency as f_??_1.5MHz, while a discharge is maintained by bulk ionizations at high frequency as f_??_10MHz. The results also show that a discharge at middle frequency as 1.5_??_f_??_10MHz, is explained from the point of view of the transition of the mechanism which maintains a discharge. It is also shown that the excitation profiles exhibit double layers near the electrodes in nitrogen at 13.56MHz, 60W and the gas pressure p, p_??_67Pa.

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The temperature dependence of the drift velocity, W, and the product of the longitudinal diffusion coefficient and the gas number density, ND_L, of electrons in the pure CO₂ gas was measured over the E/N range from 10 to 50Td and the temperature range from 297 to 483K. Both of W and ND_L decrease as the gas temperature increases over the measured temperature range at E/N_??_12Td, below which the dependence is not appreciable.

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We measured the electron drift velocity, W, and the product of the longitudinal diffusion coefficient and the gas number density, ND_L, of electrons in pure SF₆ gas over the range of E/N from about 100 Td to 800 Td by using the double-shutter electron drift tube. The present drift velocity agreed very well with other published results over 400 2≤E/N≤800 Td but was considerably higher than the only reported velocity in 200 _??_ E/N _??_ 300 Td. The present ND_L was slightly lower (about 7%) than Aschwanden's result but was considerably lower than Xiao's recent measurement.

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The drift velocity (W) and the product of the gas number density and the longitudinal diffusion coefficient (ND_L) of electrons have been measured in pure NO, and in the 4.99% and 0.498% nitric oxide (NO)-argon (Ar) mixtures by using the double-shutter drift tube with variable drift distance. The range of the measurements covered were: 0.4≤E/N≤500Td and 0.15≤p₀≤25 torr in pure NO, 0.1≤E/N≤50 Td and 1≤p₀≤120 torr in the 4.99% NO-Ar mixture, and 0.35≤E/N≤20 Td and 5≤p₀≤100 torr in the 0.498% NO-Ar mixture. All measurements were carried out at room temperature.

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We regard the procedure of deriving a set of electron collision cross sections for an atom or a molecule from electron swarm data as one of the optimization problems and tried to apply the simplex algorithm to the procedure. We established a procedure for estimating a cross section accurately and estimated the momentum transfer cross sections of Ar and Xe from the actually measured swarm data using this method. We confirmed that the electron swarm method can be remarkably improved both in accuracy and speed by applying the simplex algorithm.

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It is well known that the profile of the cross section of the resonance excitation 1s4 of Krypton in the electron collision cross section set compiled by M.Hayashi has sharp peak after the rise up from the threshold. We have investigated on the influence of the "sharp peak" to the electron transport charachteristics in the equilibrium and non-equilibrium regions. Because of the comparision, we introduced another excitation cross section which was removed the sharp peak from the cross section of 1s₄. We calculated the electron transport charachteristics using these two kind of electron collision cross sections. It is found that the electron transport charachteristics in the energy equilibrium region becomes almost the same results, but that in the non-equilibrium region becomes the results of large differences.

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Graphite (C) and catalyst (Ni/Y)-contained graphite (C-Ni/Y) substrates were processed by a welding torch arc in both DC and AC mode under open air. Multiwall carbon nanotubes were obtained at the arc spot surface on C-Ni/Y substrate for DC and AC arc, and on C substrate for AC arc. The field emission abilities of these arc spot surface were tested in a diode system. The emission current increased in the order of the surfaces of C-Ni/Y substrate for AC arc, of C substrate for DC arc, and of C-Ni/Y substrate for DC arc. This order was the same as the increase of nanotube density and the decrease of coexisting nanoparticle density.

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