Pattern phenomena in an rf discharge dusty plasma system

Various dust patterns are observed in an rf discharge dusty plasma system. According to the dust growth process from small to large in size, the formation of different dust patterns can be divided into two stages: the small-particle stage (or dust cloud stage), and the large-particle stage (or dust crystal stage). The evolution relations between different dust patterns with gas pressure changing are investigated. Dust voids, dust acoustic waves and strong turbulence modes are presented at the small-particle stage. The self-organized dust lattices and dust clusters are investigated at the large-particle stage. The static structure of a dust lattice is characterized by means of the pair correlation function. Dust clusters formed by particles with different numbers and the regular evolution of the clusters with gas pressure are also investigated. The packing sequences of dust clusters are verified through two-dimensional confined molecular dynamics simulations.     

Absolute populations of argon metastable states in an rf discharge plasma

Absolute populations of argon metastable states in the plasma of an rf discharge in pure argon and an argon-silane mixture are determined.     

Spectroscopic study of a glow discharge in krypton

The concentrations of excited atoms at the 4p⁵5s and 4p⁵5p levels of Kr I are determined by the reabsorption and emission methods. The absolute values off for ten Kr I lines in the infrared region of the spectrum are determined from the known value off ₈₈₁₂ and from measured relative values of the oscillator strengths. Processes leading to the formation and decay of excited states of krypton atoms are discussed.In conclusion, the authors wish to thank Professor A. N. Tekuchev for valuable comments, and also Yu. P. Grigorov, T. F. Dubtsov, L. V. Zaitsev, and V. S. Korchunov for assisting with the experiments.     

High resolution optogalvanic study in nitrogen discharge

Doppler limited high resolution spectrum in the wavelength region 17224 to 17236 cm⁻¹ of the first positive system (B ³Π _g −A ³Σ _u ⁺ ) of the N₂ molecule is recorded by optogalvanic spectroscopic technique using a single mode ring dye laser. It is observed that the intensity and line width of the rotational line increase with the discharge current. Dependence of the collision broadening coefficient on the current was also evaluated.     

Spectroscopic diagnostics for an electrical discharge plasma in a liquid

We conducted spectroscopic studies of an electrical discharge plasma in a liquid, used for synthesis of nanosized particles of metals and their compounds. From the intensity ratio of the copper lines, we estimated the electron temperature, and from the Stark broadening of the hydrogen lines H _α we determined the electron density in the electrical discharge plasma. Information about the concentration of copper atoms in the discharge was obtained from analysis of the spectra in the region of resonance lines of copper. We carried out a comparative analysis of the plasma parameters for spark and arc discharges in water, ethanol, and air. Based on the equation of state for an ideal plasma, taking into account the Debye correction, we estimated the pressure in the plasma channel.     

Ion bombardment of amorphous silicon films during plasma-enhanced chemical vapor deposition in an rf discharge

The characteristics of ion and electron fluxes to the surface of a growing silicon film are investigated in various rf discharge regimes in silane at frequencies of 13.56 MHz and 58 MHz in plasma-enhanced chemical vapor-deposition (PECVD) apparatus. The energy spectra of the ions and electrons bombarding the growing film are measured. The electronic properties of films grown under various degrees of ion bombardment are studied. The correlation of these properties with the ion parameters in the rf discharge plasma during film growth is discussed. Zh. Tekh. Fiz. 68, 52–59 (February 1998)     

Characteristics of an argon rf plasma: Active discharge and laminar sonic flow region

The electron density, the excitation and the gas temperatures have been obtained from optical spectrometric, microwave interferometric and thermocouple measurements in an argon rf plasma. The investigation was carried out in an active discharge and a channel region characterized by sonic laminar flow. Optical measurements of the excitation temperature were made in the 4000–5000 Å range for discharge pressures of ∼ 63–644 torr and input rf power of 42–60 kW. Excitation temperatures in the discharge ranged between ∼ 7000–10,000 K. Electron densities measured by optical and microwave techniques showed good agreement. Thermocouple measurements in the channel and N₂ rotational spectra from traces of N₂ injected in the argon, as well as gas dynamic considerations, indicated that the gas temperature in the discharge and the channel regions were 2900–4400K and 1900–3300K, respectively. These values were substantially lower than the excitation temperatures corresponding to these regions, indicating that the plasma was in a two-temperature state in both regions. Standard tests for local thermal equilibrium (LTE) showed that the first excited level of argon constituted the bottleneck level.     

Spectroscopic investigation of the cathode region of an independent glow discharge in He

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 51, No. 2, pp. 203–207, August, 1989.     

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N2-Ar射频放电等离子体广泛应用于微电子工业的刻蚀、氮化物薄膜的制备及金属表面氮化等技术领域。开发了N2-Ar混合气体容性耦合射频放电PIC/MC自洽模型,模型主要描述了e-,N2+,N+,Ar+等主要带电粒子的行为分布。等离子体的碰撞过程分别考虑了带电粒子(e-,N2+,N+,Ar+)与基态中性N2分子和Ar原子的21种碰撞反应过程。模拟结果表明,在纯N2及N2-Ar混合气体容性耦合射频放电中,各种带电粒子的数密度都在等离子体区达到最大值,且氮分子离子为主要粒子;在N2容性耦合射频放电中,加入10%氩气时,N+平均能量有所增加,在射频电极处两种氮离子(N2+,N+)高能粒子所占比例增加。本研究对认识N2-Ar射频放电等离子体过程微观机理具重要意义。     

空心阴极放电条纹特性的光谱诊断

利用发射光谱法,研究了圆柱型空心阴极放电条纹的特性.测量了条纹区的发射光谱,在此基础E计算得到r电子激发温度、相对电子密度和电子平均能量的空间分布特性.结果表明条纹区的光强、电子激发温度和电子密度均呈非等幅的周期性变化.与暗纹中心处相比,明纹中心具有较高的电子激发温度和较低的电子密度.由阴极向阳极,明纹中心处的电子激发温度幅值逐渐减小.此外,条纹区的电子激发温度随着电流的增加而增加.