scholarly journals Charging and trapping of macroparticles in near-electrode regions of fluorocarbon plasmas with negative ions

2001 ◽  
Vol 8 (7) ◽  
pp. 3490-3497 ◽  
Author(s):  
K. N. Ostrikov ◽  
S. Kumar ◽  
H. Sugai
Keyword(s):  
Negative Ions ◽  
Fluorocarbon Plasmas

Negative ions in single and dual frequency capacitively coupled fluorocarbon plasmas

2007 ◽  
Vol 16 (1) ◽  
pp. S87-S93 ◽  
Author(s):  
G A Curley ◽  
D Marić ◽  
J-P Booth ◽  
C S Corr ◽  
P Chabert ◽  
...  
Keyword(s):  
Negative Ions ◽  
Dual Frequency ◽  
Capacitively Coupled ◽  
Fluorocarbon Plasmas

Diagnostics And Control Of High-Density Etching Plasmas

1995 ◽  
Vol 406 ◽  
Author(s):  
H. Sugai ◽  
K. Nakamura ◽  
T. H. Ahn ◽  
M. Nakamur
Keyword(s):  
Negative Ions ◽  
High Density ◽  
Negative Ion ◽  
Pulsed Plasma ◽  
Surface Charges ◽  
Time Resolved ◽  
Inductively Coupled ◽  
Fluorocarbon Plasmas ◽  
Coupled Plasmas ◽  
And Control

AbstractAdvanced diagnostics of high-density inductively coupled plasmas (ICPs) are presented supporting the following three proposals of innovative etching modes: First, pulsed plasma etching mode can suppress charge-up on high-aspect-ratio micro-patterns. In order to understand the mechanism, time-resolved measurements of electrons, chlorine atoms and negative ions in a pulsed chlorine ICP are performed. As a result of electron cooling and negative ion yield in afterglow, electrons are found to be accelerated toward a rf-biased electrode, thus neutralizing positive surface charges on that. Second, downstream etching mode using C4F8 gas enables high etch selectivity of SiO2 to Si. The reason for this is qualitatively discussed using comprehensive measurements of spatial distributions of CF3, CF2, CF and F densities in CF4 and C4F8 plasmas. Third, hot wall etching mode also enables high selectibity etching in fluorocarbon plasmas. Radical diagnostics reveal that wall heating dramatically modifies the radical composition of both CF4 and C4F8 plasmas, and it improves the etch selectivity and reproducibility.

Numerical Simulation of Leakage Current on Conductive Insulator Surface

2019 ◽  
Vol 8 (4) ◽  
pp. 9487-9492
Keyword(s):  
Numerical Simulation ◽  
Electric Field ◽  
Leakage Current ◽  
Method Of Lines ◽  
Electron Attachment ◽  
Negative Ions ◽  
Conduction Current ◽  
Insulator Surface ◽  
Finite Difference Approximations ◽  
Positive Ions

The outdoor insulator is commonly exposed to environmental pollution. The presence of water like raindrops and dew on the contaminant surface can lead to surface degradation due to leakage current. However, the physical process of this phenomenon is not well understood. Hence, in this study we develop a mathematical model of leakage current on the outdoor insulator surface using the Nernst Planck theory which accounts for the charge transport between the electrodes (negative and positive electrode) and charge generation mechanism. Meanwhile the electric field obeys Poisson’s equation. Method of Lines technique is used to solve the model numerically in which it converts the PDE into a system of ODEs by Finite Difference Approximations. The numerical simulation compares reasonably well with the experimental conduction current. The findings from the simulation shows that the conduction current is affected by the electric field distribution and charge concentration. The rise of the conduction current is due to the distribution of positive ion while the dominancy of electron attachment with neutral molecule and recombination with positive ions has caused a significant reduction of electron and increment of negative ions.

scholarly journals Mass-resolved electronic circular dichroism ion spectroscopy

Science ◽  
2020 ◽  
Vol 368 (6498) ◽  
pp. 1465-1468 ◽  
Author(s):  
Steven Daly ◽  
Frédéric Rosu ◽  
Valérie Gabelica
Keyword(s):  
Circular Dichroism ◽  
Three Dimensional ◽  
Polarized Light ◽  
Negative Ions ◽  
Data Interpretation ◽  
Electronic Circular Dichroism ◽  
Circularly Polarized Light ◽  
Chiral Compounds ◽  
Electron Photodetachment ◽  
Circular Dichroïsm

DNA and proteins are chiral: Their three-dimensional structures cannot be superimposed with their mirror images. Circular dichroism spectroscopy is widely used to characterize chiral compounds, but data interpretation is difficult in the case of mixtures. We recorded the electronic circular dichroism spectra of DNA helices separated in a mass spectrometer. We studied guanine-rich strands having various secondary structures, electrosprayed them as negative ions, irradiated them with an ultraviolet nanosecond optical parametric oscillator laser, and measured the difference in electron photodetachment efficiency between left and right circularly polarized light. The reconstructed circular dichroism ion spectra resembled those of their solution-phase counterparts, thereby allowing us to assign the DNA helical topology. The ability to measure circular dichroism directly on biomolecular ions expands the capabilities of mass spectrometry for structural analysis.

scholarly journals Effect of Low-Pressure Plasma Treatment Parameters on Wrinkle Features

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3852
Author(s):  
Bongjun Gu ◽  
Dongwook Ko ◽  
Sungjin Jo ◽  
Dong Choon Hyun ◽  
Hyeon-Ju Oh ◽  
...  
Keyword(s):  
Power Flow ◽  
Treatment Time ◽  
Argon Plasma ◽  
Negative Ions ◽  
Low Pressure ◽  
Nitrogen Plasma ◽  
Pressure Plasma ◽  
Positive Ions ◽  
Low Pressure Plasma ◽  
Optical Adhesive

Wrinkles attract significant attention due to their ability to enhance the mechanical and optical characteristics of various optoelectronic devices. We report the effect of the plasma gas type, power, flow rate, and treatment time on the wrinkle features. When an optical adhesive was treated using a low-pressure plasma of oxygen, argon, and nitrogen, the oxygen and argon plasma generated wrinkles with the lowest and highest wavelengths, respectively. The increase in the power of the nitrogen and oxygen plasma increased the wavelengths and heights of the wrinkles; however, the increase in the power of the argon plasma increased the wavelengths and decreased the heights of the wrinkles. Argon molecules are heavier and smaller than nitrogen and oxygen molecules that have similar weights and sizes; moreover, the argon plasma comprises positive ions while the oxygen and nitrogen plasma comprise negative ions. This resulted in differences in the wrinkle features. It was concluded that a combination of different plasma gases could achieve exclusive control over either the wavelength or the height and allow a thorough analysis of the correlation between the wrinkle features and the characteristics of the electronic devices.

Soliton turbulence in electronegative plasma due to head-on collision of multi solitons

2020 ◽  
Vol 75 (12) ◽  
pp. 999-1007
Author(s):  
Rustam Ali ◽  
Anjali Sharma ◽  
Prasanta Chatterjee
Keyword(s):  
Wave Field ◽  
Soliton Solutions ◽  
Negative Ions ◽  
First Integral ◽  
Statistical Properties ◽  
Charged Dust ◽  
Bilinear Method ◽  
Electronegative Plasma ◽  
Kdv Equations ◽  
First Four Moments

AbstractHead-on interaction of four dust ion acoustic (DIA) solitons and the statistical properties of the wave field due to head-on interaction of solitons moving in opposite direction is studied in the framework of two Korteweg de Vries (KdV) equations. The extended Poincaré–Lighthill–Kuo (PLK) method is applied to obtain two opposite moving KdV equations from an unmagnetized four component plasma model consisting of Maxwellian negative ions, cold mobile positive ions, κ-distributed electrons and positively charged dust grains. Hirota’s bilinear method is adopted to obtain two-soliton solutions of both the KdV equations and accordingly act of soliton turbulence is presented due to head-on collision of four solitons. The amplitude and shape of the resultant wave profile at the point of strongest interaction are obtained. To see the effect of head-on collision on the statistical properties of wave field the first four moments are computed. It is observed that the head-on collision has no effect on the first integral moment while the second, third and fourth moments increase in the dominant interaction region of four solitons, which is a clean indication of soliton turbulence.

Solitary waves in a dusty adiabatic electronegative plasma

2010 ◽  
Vol 76 (3-4) ◽  
pp. 409-418 ◽  
Author(s):  
A. A. MAMUN ◽  
K. S. ASHRAFI ◽  
M. G. M. ANOWAR
Keyword(s):  
Solitary Waves ◽  
Vries Equation ◽  
Negative Ions ◽  
Finite Amplitude ◽  
Reductive Perturbation Method ◽  
Charged Dust ◽  
Electronegative Plasma ◽  
Ion Acoustic ◽  
Basic Features ◽  
Electronegative Plasmas

AbstractThe dust ion-acoustic solitary waves (SWs) in an unmagnetized dusty adiabatic electronegative plasma containing inertialess adiabatic electrons, inertial single charged adiabatic positive and negative ions, and stationary arbitrarily (positively and negatively) charged dust have been theoretically studied. The reductive perturbation method has been employed to derive the Korteweg-de Vries equation which admits an SW solution. The combined effects of the adiabaticity of plasma particles, inertia of positive or negative ions, and presence of positively or negatively charged dust, which are found to significantly modify the basic features of small but finite-amplitude dust-ion-acoustic SWs, are explicitly examined. The implications of our results in space and laboratory dusty electronegative plasmas are briefly discussed.

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