Kinetics of Plasma Etching Silicon with Nitrogen Trifluoride

1986 ◽  
Vol 68 ◽  
Author(s):  
Harvey G. Stenger ◽  
G. S. Akiki
Keyword(s):  
Kinetic Model ◽  
Plasma Etching ◽  
Etch Rate ◽  
Radial Flow ◽  
Crystalline Silicon ◽  
A Value ◽  
Atomic Fluorine ◽  
Kinetics Of ◽  
Elementary Chemical ◽  
Good Agreement

AbstractA kinetic model, composed of elementary chemical reactions, is derived to predict the etch rate of crystalline silicon with NF3 in a plasma discharge.Experimental data taken from a radial flow plasma etching reactor is used to determine the model's kinetic parameters.The rate constant for atomic fluorine reacting with <100> silicon was determined to be 1410 cm/min at 25 °C, in good agreement with a value obtained by other investigators.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

Pyrolysis of Sugarcane Bagasse: A Consecutive Reactions Kinetic Model from TGA Experiments

2010 ◽  
Vol 660-661 ◽  
pp. 593-598 ◽  
Author(s):  
Kássia Graciele dos Santos ◽  
Taisa S. Lira ◽  
Valéria V. Murata ◽  
Marco Gianesella ◽  
Marcos A.S. Barrozo
Keyword(s):  
Kinetic Model ◽  
Sugarcane Bagasse ◽  
Room Temperature ◽  
Linear Method ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Exponential Factor ◽  
Consecutive Reactions ◽  
Kinetics Of ◽  
Good Agreement

The pyrolysis kinetics of sugarcane bagasse in nitrogen flow was studied by thermogravimetric analysis from room temperature to 1173 K at different heating rates (1.5, 3, 5, 10, 15, 20, 30 and 50 K/min). As there are three distinct devolatilization peaks in the DTG curve, each peak was associated to thermal decomposition of an individual biomass subcomponent (hemicellulose, cellulose and lignin). The kinetic model adopted was a consecutive reactions model. The kinetic parameters of the pyrolysis process, such as activation energy and pre-exponential factor, were calculated by least squares non-linear method and Scilab are used as the simulation tool. The simulated results showed a good agreement with the experimental data and the parameters found are similar to reported by the literature.

scholarly journals Further study on kinetic modeling of sunflower oil methanolysis catalyzed by calcium-based catalysts

2016 ◽  
Vol 22 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Marija Miladinovic ◽  
Marija Tasic ◽  
Olivera Stamenkovic ◽  
Vlada Veljkovic ◽  
Dejan Skala
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Kinetic Model ◽  
Sunflower Oil ◽  
Coefficient Of Determination ◽  
Reaction Conditions ◽  
High Coefficient ◽  
Relative Percentage ◽  
Kinetics Of ◽  
Good Agreement

The kinetic model, which was originally developed for sunflower oil methanolysis catalyzed by CaO.ZnO, was examined for several other calcium-based catalysts like neat CaO, quicklime and Ca(OH)2. This model including triacylglycerols mass transfer- and chemically-controlled regimes demonstrated a good agreement with the experimental data in terms of a high coefficient of determination (0.971?0.022) and acceptable mean relative percentage deviation (?15.9%). Hence, this model is recommended for modeling the kinetics of sunflower oil methanolysis over calcium-based catalysts under widely ranging reaction conditions.

scholarly journals Kinetics of the sunflower oil ethanolysis using CaO as catalyst

2016 ◽  
Vol 22 (4) ◽  
pp. 409-418 ◽  
Author(s):  
Ana Velickovic ◽  
Jelena Avramovic ◽  
Olivera Stamenkovic ◽  
Vlada Veljkovic
Keyword(s):  
Kinetic Model ◽  
Sunflower Oil ◽  
Reaction Rate Constant ◽  
Ethyl Esters ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Reaction Conditions ◽  
Data Points ◽  
Kinetics Of ◽  
Good Agreement

The ethanolysis of sunflower oil catalyzed by calcium oxide was studied in wider ranges of the reaction conditions: temperature 65-75?C, ethanol-to-oil molar ratio 6:1-18:1 and catalyst loading 10-20% in order to determine the reaction kinetics. The proposed kinetic model of the sunflower oil ethanolysis included the changing and first-order reaction mechanism with respect to triacylglycerols and fatty acid ethyl esters. The kinetic parameters were determined and correlated with the process variables. The Arrhenius equation could be applied to the reaction rate constant with the activation energy of 94.0 kJ/mol. The proposed kinetic model showed a good agreement with the experimental data with the mean relative percentage deviation of ?13% (based on 256 data points).

Standardisation of von Willebrand Factor in Therapeutic Concentrates: Calibration of the 1st International Standard for von Willebrand Factor Concentrate (00/514)

2002 ◽  
Vol 88 (09) ◽  
pp. 380-386 ◽  
Author(s):  
Dawn Sands ◽  
Andrew Chang ◽  
Claudine Mazurier ◽  
Anthony Hubbard
Keyword(s):  
Von Willebrand Factor ◽  
International Study ◽  
Expert Committee ◽  
International Standard ◽  
A Value ◽  
Significant Difference ◽  
Factor Concentrate ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Good Agreement

SummaryAn international study involving 26 laboratories assayed two candidate von Willebrand Factor (VWF) concentrates (B and C) for VWF:Antigen (VWF:Ag), VWF:Ristocetin Cofactor (VWF:RCo) and VWF:Collagen binding (VWF:CB) relative to the 4th International Standard Factor VIII/VWF Plasma (4th IS Plasma) (97/586). Estimates of VWF:Ag showed good agreement between different methods, for both candidates, and the overall combined means were 11.01 IU/ml with inter-laboratory variability (GCV) of 10.9% for candidate B and 14.01 IU/ml (GCV 11.8%) for candidate C. Estimates of VWF:RCo showed no significant difference between methods for both candidates and gave overall means of 9.38 IU/ml (GCV 23.7%) for candidate B and 10.19 IU/ml (GCV 24.4%) for candidate C. Prior to the calibration of the candidates for VWF:CB it was necessary to calibrate the 4th IS Plasma relative to local frozen normal plasma pools; there was good agreement between different collagen reagents and an overall mean of 0.83 IU per ampoule (GCV 11.8%) was assigned. In contrast, estimates of VWF:CB in both candidates showed large differences between collagen reagents with inter-laboratory GCV’s of 40%. Candidate B (00/514) was established as the 1st International Standard von Willebrand Factor Concentrate by the WHO Expert Committee on Biological Standardisation in November 2001 with assigned values for VWF:Ag (11.0 IU/ampoule) and VWF:RCo (9.4 IU/ampoule). Large inter-laboratory variability of estimates precluded the assignment of a value for VWF:CB.

scholarly journals Torrefaction Thermogravimetric Analysis and Kinetics of Sorghum Distilled Residue for Sustainable Fuel Production

2021 ◽  
Vol 13 (8) ◽  
pp. 4246
Author(s):  
Shih-Wei Yen ◽  
Wei-Hsin Chen ◽  
Jo-Shu Chang ◽  
Chun-Fong Eng ◽  
Salman Raza Naqvi ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Pso Algorithm ◽  
Nitrogen Atmosphere ◽  
Computational Method ◽  
Weight Changes ◽  
Design And Optimization ◽  
Thermogravimetric Analyzer ◽  
Model Free ◽  
Different Temperatures ◽  
Kinetics Of

This study investigated the kinetics of isothermal torrefaction of sorghum distilled residue (SDR), the main byproduct of the sorghum liquor-making process. The samples chosen were torrefied isothermally at five different temperatures under a nitrogen atmosphere in a thermogravimetric analyzer. Afterward, two different kinetic methods, the traditional model-free approach, and a two-step parallel reaction (TPR) kinetic model, were used to obtain the torrefaction kinetics of SDR. With the acquired 92–97% fit quality, which is the degree of similarity between calculated and real torrefaction curves, the traditional method approached using the Arrhenius equation showed a poor ability on kinetics prediction, whereas the TPR kinetic model optimized by the particle swarm optimization (PSO) algorithm showed that all the fit qualities are as high as 99%. The results suggest that PSO can simulate the actual torrefaction kinetics more accurately than the traditional kinetics approach. Moreover, the PSO method can be further employed for simulating the weight changes of reaction intermediates throughout the process. This computational method could be used as a powerful tool for industrial design and optimization in the biochar manufacturing process.

Kinetics of silicon nitride crystallization in N+-implanted silicon

1989 ◽  
Vol 4 (2) ◽  
pp. 394-398 ◽  
Author(s):  
V. S. Kaushik ◽  
A. K. Datye ◽  
D. L. Kendall ◽  
B. Martinez-Tovar ◽  
D. S. Simons ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Crystalline Silicon ◽  
Wafer Surface ◽  
Amorphous Silicon Nitride ◽  
Silicon Lattice ◽  
Nitrogen Ions ◽  
The Mean ◽  
Nitride Layers ◽  
Kinetics Of

Implantation of nitrogen at 150 KeV and a dose of 1 ⊠ 1018/cm2 into (110) silicon results in the formation of an amorphized layer at the mean ion range, and a deeper tail of nitrogen ions. Annealing studies show that the amorphized layer recrystallizes into a continuous polycrystalline Si3N4 layer after annealing for 1 h at 1200 °C. In contrast, the deeper nitrogen fraction forms discrete precipitates (located 1μm below the wafer surface) in less than 1 min at this temperature. The arcal density of these precipitates is 5 ⊠ 107/cm2 compared with a nuclei density of 1.6 ⊠ 105/cm2 in the amorphized layer at comparable annealing times. These data suggest that the nucleation step limits the recrystallization rate of amorphous silicon nitride to form continuous buried nitride layers. The nitrogen located within the damaged crystalline silicon lattice precipitates very rapidly, yielding semicoherent crystallites of β–Si3N4.

Heat-flow experiments in liquid 4He with a variable cylindrical geometry

1987 ◽  
Vol 174 ◽  
pp. 209-231 ◽  
Author(s):  
H. Gao ◽  
G. Metcalfe ◽  
T. Jung ◽  
R. P. Behringer
Keyword(s):  
Cylindrical Geometry ◽  
Small Scale ◽  
Onset Of Convection ◽  
Aspect Ratios ◽  
A Value ◽  
Prandtl Numbers ◽  
Convection Rolls ◽  
Flow Experiments ◽  
Increasing Function ◽  
Good Agreement

This paper first describes an apparatus for measuring the Nusselt number N versus the Rayleigh number R of convecting normal liquid 4He layers. The most important feature of the apparatus is its ability to provide layers of different heights d, and hence different aspect ratios [Gcy ]. The horizontal cross-section of each layer is circular, and [Gcy ] is defined by [Gcy ] = D/2d where D is the diameter of the layer. We report results for 2.4 [les ] [Gcy ] [les ] 16 and for Prandtl numbers Pr spanning 0.5 [lsim ] Pr [lsim ] 0.9 These results are presented in terms of the slope N1 = RcdN/dR evaluated just above the onset of convection at Rc. We find that N1 is only a slowly increasing function of [Gcy ] in the range 6 [lsim ] [Gcy ] [lsim ] 16, and that it has a value there which is quite close to 0.72. This value of N1 is in good agreement with variational calcuations by Ahlers et al. (1981) pertinent to parallel convection rolls in cylindrical geometry. Particularly for [Gcy ] [lsim ] 6, we find additional small-scale structure in N1 associated with changes in the number of convection rolls with changing [Gcy ]. An additional test of the linearzied hydrodynamics is given by measurements of Rc. We find good agreement between theory and our data for Rc.

Vulcanization of Elastomers. 23. The Chemical Kinetics of Vulcanization Reactions and The Physical Properties of The Vulcanizates. I

1960 ◽  
Vol 33 (2) ◽  
pp. 335-341
Author(s):  
Walter Scheele ◽  
Karl-Heinz Hillmer
Keyword(s):  
Activation Energy ◽  
Physical Properties ◽  
Chemical Kinetics ◽  
Kcal Mole ◽  
First Order ◽  
Equilibrium Swelling ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization ◽  
Limiting Value ◽  
Good Agreement

Abstract As a complement to earlier investigations, and in order to examine more closely the connection between the chemical kinetics and the changes with vulcanization time of the physical properties in the case of vulcanization reactions, we used thiuram vulcanizations as an example, and concerned ourselves with the dependence of stress values (moduli) at different degrees of elongation and different vulcanization temperatures. We found: 1. Stress values attain a limiting value, dependent on the degree of elongation, but independent of the vulcanization temperature at constant elongation. 2. The rise in stress values with the vulcanization time is characterized by an initial delay, which, however, is practically nonexistent at higher temperatures. 3. The kinetics of the increase in stress values with vulcanization time are both qualitatively and quantitatively in accord with the dependence of the reciprocal equilibrium swelling on the vulcanization time; both processes, after a retardation, go according to the first order law and at the same rate. 4. From the temperature dependence of the rate constants of reciprocal equilibrium swelling, as well as of the increase in stress, an activation energy of 22 kcal/mole can be calculated, in good agreement with the activation energy of dithiocarbamate formation in thiuram vulcanizations.

scholarly journals The kinetics of the oxidation of copper. Part II. -The limiting pressure. Evidence for the lateral diffusion of adsorbed gas

1930 ◽  
Vol 128 (808) ◽  
pp. 407-417 ◽  
Keyword(s):  
Lateral Diffusion ◽  
Adsorbed Gas ◽  
A Value ◽  
Kinetics Of ◽  
Limiting Pressure

The influence of the pressure of oxygen on the rate of oxidation of copper has been studied by earlier workers. Pilling and Bedworth working at 800°C. found that the rate of oxidation continued constant as the pressure was decreased until the pressure reached 0·3 mm. Berger found a limiting pressure of 100 mm. Hinshelwood’s work makes it clear that for activated copper at 305°C. the limiting pressure is greater than 5 mm. Palmer obtained a value of about 300 mm. The object of this work was to investigate more closely the significance of the limiting pressure.

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