A Kinetic Model for Low-Pressure RF Discharge Etching of Silicon Using SF6

1987 ◽  
Vol 98 ◽  
Author(s):  
Arit P. Paranjpe ◽  
George Kychakoff ◽  
Sidney A. Self
Keyword(s):  
Boltzmann Equation ◽  
Electron Impact ◽  
Etch Rate ◽  
Electron Number Density ◽  
Kinetics Model ◽  
Rf Discharge ◽  
Number Density ◽  
Electron Number ◽  
The Boltzmann Equation ◽  
Impact Processes

ABSTRACTThe variation of etch rate with power, pressure and flow is studied using a coupled electron and chemical kinetics model. The electron kinetics model involves a solution of the electron continuity and current continuity equations in conjunction with the Boltzmann equation. The temporal variation of the electric field, electron energy distribution function (EEDF) and electron number density in the bulk of an RF discharge, is calculated using measured current waveforms, and calculated species concentrations. Electron generation through electron-impact ionization, is balanced by attachment and diffusion losses. A time-dependent solution of the Boltzmann equation is employed to investigate the problem of non-equilibrium, between the EEDF and the instantaneous field. Rates for electron impact processes are calculated using the EEDF.Rate equations for the different species are solved to obtain steady state species concentrations. Radicals and ions produced by electron-impact processes are lost through neutral recombination, ion-ion neutralization, diffusion to reactor surfaces and flow losses. The calculated ion number densities far exceed the electron number density. A transport model that considers the diffusion of etchant species to the wafer and subsequent reaction, is used to compute the etch rate.

TESTING OF NICKEL-CHROME ALLOY AS A TIP MATERIAL FOR MULTI-TIP LANGMUIR PROBES

2014 ◽  
Vol 21 (04) ◽  
pp. 1450056 ◽  
Author(s):  
MUHAMMAD YASIN NAZ ◽  
SHAZIA SHUKRULLAH ◽  
ABDUL GHAFFAR ◽  
IMRAN SHAKIR ◽  
SAMI ULLAH ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Inductively Coupled Plasma ◽  
Electron Number Density ◽  
Diagnostic System ◽  
Input Power ◽  
Repeated Measurements ◽  
Gas Pressure ◽  
Rf Discharge ◽  
Number Density ◽  
Electron Number

The electrostatic probes are considered to be the most powerful and experimentally simplest technique for plasma characterization. The objective of the work was to test the nickel-chrome alloy as probe tip material for characterization of RF discharge plasmas. In order to meet the objective, a triple Langmuir probe diagnostic system and associated driving circuit was designed and tested in inductively coupled plasma (ICP) generated by a 13.56 MHz radio frequency (RF) source. Using this probe diagnostic, the electron temperature, electron number density and ion saturation current were measured as a function of input RF power and filling gas pressure. An increasing trend was noticed in electron temperature and electron number density with input power whilst a decreasing trend was evident in these parameters for increasing nitrogen gas pressure. The overall variations in electron temperature and electron number density after repeated measurements were ranging from 5% to 12% and 3% to 13%, respectively.

scholarly journals Influence of water vapour on the height distribution of positive ions, effective recombination coefficient and ionisation balance in the quiet lower ionosphere

2014 ◽  
Vol 32 (3) ◽  
pp. 207-222 ◽  
Author(s):  
V. Barabash ◽  
A. Osepian ◽  
P. Dalin
Keyword(s):  
Water Vapour ◽  
Electron Density ◽  
Electron Number Density ◽  
Lower Ionosphere ◽  
Recombination Coefficient ◽  
Height Distribution ◽  
Number Density ◽  
Electron Number ◽  
Water Vapour Concentration ◽  
Vapour Concentration

Abstract. Mesospheric water vapour concentration effects on the ion composition and electron density in the lower ionosphere under quiet geophysical conditions were examined. Water vapour is an important compound in the mesosphere and the lower thermosphere that affects ion composition due to hydrogen radical production and consequently modifies the electron number density. Recent lower-ionosphere investigations have primarily concentrated on the geomagnetic disturbance periods. Meanwhile, studies on the electron density under quiet conditions are quite rare. The goal of this study is to contribute to a better understanding of the ionospheric parameter responses to water vapour variability in the quiet lower ionosphere. By applying a numerical D region ion chemistry model, we evaluated efficiencies for the channels forming hydrated cluster ions from the NO+ and O2+ primary ions (i.e. NO+.H2O and O2+.H2O, respectively), and the channel forming H+(H2O)n proton hydrates from water clusters at different altitudes using profiles with low and high water vapour concentrations. Profiles for positive ions, effective recombination coefficients and electrons were modelled for three particular cases using electron density measurements obtained during rocket campaigns. It was found that the water vapour concentration variations in the mesosphere affect the position of both the Cl2+ proton hydrate layer upper border, comprising the NO+(H2O)n and O2+(H2O)n hydrated cluster ions, and the Cl1+ hydrate cluster layer lower border, comprising the H+(H2O)n pure proton hydrates, as well as the numerical cluster densities. The water variations caused large changes in the effective recombination coefficient and electron density between altitudes of 75 and 87 km. However, the effective recombination coefficient, αeff, and electron number density did not respond even to large water vapour concentration variations occurring at other altitudes in the mesosphere. We determined the water vapour concentration upper limit at altitudes between 75 and 87 km, beyond which the water vapour concentration ceases to influence the numerical densities of Cl2+ and Cl1+, the effective recombination coefficient and the electron number density in the summer ionosphere. This water vapour concentration limit corresponds to values found in the H2O-1 profile that was observed in the summer mesosphere by the Upper Atmosphere Research Satellite (UARS). The electron density modelled using the H2O-1 profile agreed well with the electron density measured in the summer ionosphere when the measured profiles did not have sharp gradients. For sharp gradients in electron and positive ion number densities, a water profile that can reproduce the characteristic behaviour of the ionospheric parameters should have an inhomogeneous height distribution of water vapour.

Characteristics of a resonant iris microwave-induced nitrogen plasma

2016 ◽  
Vol 31 (5) ◽  
pp. 1097-1104 ◽  
Author(s):  
Daniel A. Goncalves ◽  
Tina McSweeney ◽  
George L. Donati
Keyword(s):  
Electron Number Density ◽  
Nitrogen Plasma ◽  
Number Density ◽  
Electron Number ◽  
Temperature Electron ◽  
Mip Oes

Temperature, electron number density and robustness profiles of a N2 plasma contribute for more sensitive and accurate MIP OES determinations.

scholarly journals Excitation and analytical characteristics of an ethanol loaded U-shaped arc

2003 ◽  
Vol 68 (2) ◽  
pp. 109-118 ◽  
Author(s):  
Marija Raskovic ◽  
Ivanka Holclajtner-Antunovic ◽  
Mirjana Tripkovic ◽  
Dragan Markovic
Keyword(s):  
Spectral Line ◽  
Electron Number Density ◽  
Ethanol Solution ◽  
Number Density ◽  
Electron Number ◽  
Plasma Parameters ◽  
Line Intensities ◽  
Ethanol Addition ◽  
Plasma Characteristics ◽  
Dc Arc

The effect of the ethanol load on the discharge and analytical parameters of an argon stabilized U-shaped DC arc has been recorded. Measurements of the radial distribution of the apparent temperatures and the electron number density of the DC plasma showed that ethanol addition causes a decrease in both plasma parameters. The changes in the plasma characteristics, as well as in transport and atomisation processes of the analyte cause a general change in the spectral line intensities, which depends on the physical characteristics of the analyte and the quantity of ethanol loaded into the plasma. Improved detection limits were obtained for V and Mn when a 10%(v/v) water?ethanol solution was nebulized into the plasma.

Jeans-Alfvén instability in quantum dusty magnetoplasmas

2017 ◽  
Vol 83 (1) ◽  
Author(s):  
M. Jamil ◽  
A. Rasheed ◽  
M. Amir ◽  
G. Abbas ◽  
Young-Dae Jung
Keyword(s):  
Significant Contribution ◽  
Electron Number Density ◽  
Fluid Model ◽  
Low Frequency ◽  
Momentum Balance ◽  
Number Density ◽  
Electron Number ◽  
Momentum Balance Equation ◽  
Quantum Plasmas ◽  
Jeans Instability

The Jeans instability is examined in quantum dusty magnetoplasmas due to low-frequency magnetosonic perturbations. The fluid model consisting of the momentum balance equation for quantum plasmas, Poisson’s equation for the gravitational potential and Maxwell’s equations for electromagnetic magnetosonic perturbations is solved. The numerical analysis elaborates the significant contribution of magnetic field, electron number density and variable dust mass to the Jeans instability.

Calculated electron number density profiles for the aeroassist flight experiment

1992 ◽  
Vol 29 (5) ◽  
pp. 621-626 ◽  
Author(s):  
Robert B. Greendyke ◽  
Peter A. Gnoffo ◽  
R. Wes Lawrence
Keyword(s):  
Electron Number Density ◽  
Number Density ◽  
Electron Number ◽  
Density Profiles ◽  
Flight Experiment
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