The Effects of Modulation on an RF Discharge in Silane and on the Deposited a-Si:H

1987 ◽  
Vol 98 ◽  
Author(s):  
L. J. Overzet ◽  
J. T. Verdeyen ◽  
R. M. Roth ◽  
F. F. Carasco
Keyword(s):  
Electron Density ◽  
Average Power ◽  
Optical Emission ◽  
Rf Discharge ◽  
Absorption Coefficients ◽  
Average Value ◽  
Optical Bandgaps ◽  
Time Average ◽  
Substrate Temperatures ◽  
Attachment Process

ABSTRACTThe time evolution of the electron density and the optical emission intensity in response to a square wave modulated RF excitation of helium-silane mixtures has been studied and compared to that for the more conventional CW discharge. In addition, the films deposited from CW and modulated RF glows have-been compared on the basis of absorption coefficients and photoconductivities. Films deposited from modulated glows at substrate temperatures below 200°C have significantly smaller optical bandgaps than those deposited from comparable CW discharges. The bulk electron density in the modulated discharge undergoes a complex temporal variation and its time average value can be significantly larger than that in the CW glow despite the lower average power. A dissociative attachment process involving silane radicals, SiHn (n = 1 to 3), is identified as the most probable cause.

scholarly journals Machine Learning Prediction of Electron Density and Temperature from Optical Emission Spectroscopy in Nitrogen Plasma

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1221
Author(s):  
Jun-Hyoung Park ◽  
Ji-Ho Cho ◽  
Jung-Sik Yoon ◽  
Jung-Ho Song
Keyword(s):  
Machine Learning ◽  
Electron Temperature ◽  
Real Time ◽  
Electron Density ◽  
Emission Spectroscopy ◽  
Optical Emission Spectroscopy ◽  
Optical Emission ◽  
Plasma Parameters ◽  
Plasma Nitridation

We present a non-invasive approach for monitoring plasma parameters such as the electron temperature and density inside a radio-frequency (RF) plasma nitridation device using optical emission spectroscopy (OES) in conjunction with multivariate data analysis. Instead of relying on a theoretical model of the plasma emission to extract plasma parameters from the OES, an empirical correlation was established on the basis of simultaneous OES and other diagnostics. Additionally, we developed a machine learning (ML)-based virtual metrology model for real-time Te and ne monitoring in plasma nitridation processes using an in situ OES sensor. The results showed that the prediction accuracy of electron density was 97% and that of electron temperature was 90%. This method is especially useful in plasma processing because it provides in-situ and real-time analysis without disturbing the plasma or interfering with the process.

scholarly journals PARAMETERS OF HYDROGEN PLASMA STREAMS IN QSPA-M AND THEIR DEPENDENCE ON EXTERNAL MAGNETIC FIELD

2021 ◽  
pp. 61-64
Author(s):  
M.S. Ladygina ◽  
Yu.V. Petrov ◽  
D.V. Yeliseev ◽  
V.A. Makhlai ◽  
N.V. Kulik ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Density ◽  
Hydrogen Plasma ◽  
Experimental Studies ◽  
Optical Emission ◽  
Plasma Electron ◽  
Plasma Stream ◽  
Visible Radiation ◽  
Order Of Magnitude ◽  
Plasma Electron Density

Present experimental studies are aimed at analysis of hydrogen plasma stream parameters in various working regimes of QSPA-M operation. Temporal distributions of plasma electron density are reconstructed with optical emission spectroscopy. The magnetic field influence on plasma streams parameters is analyzed. It is shown that in regimes with additional magnetic field the plasma electron density increases by an order of magnitude in comparison with a density value without magnetic field. The plasma velocity and energy density parameters as well as their temporal behaviors were estimatedin different operating regimes of QSPA-M facility. Features of plasma visible radiation were analyzed. This information is important for QSPA-M applications in experiments on interaction of powerful plasma streams with material surfaces.

scholarly journals Real-life data – a characteristic of RA in patients with cardiovascular diseases on the background of treatment with biological agents

2019 ◽  
pp. 10-17
Keyword(s):  
Cardiovascular Diseases ◽  
Real Life ◽  
Biological Agents ◽  
Mean Values ◽  
Average Value ◽  
Life Data ◽  
Real Life Data ◽  
Significant Difference ◽  
Time Average ◽  
Therapeutic Behavior

The purpose of this study is to analyze real-life data in order to characterize patients with RA and cardiovascular diseases that are treated with biological agents. Material and Methods: In a retrospective study, data from real clinical practice were analyzed in 195 patients with seropositive RA, which are being treated with biological agents. Results: In patients with existing CVD, significantly higher mean ESR values ​​(23.95 vs. 19.31, p = 0.031) and CRP (6.41 vs. 3.36, p = 0.004) were detected over the period of the study period of treatment. In contrast to the laboratory parameters, mean values of clinical parameters of RA - TJC, SJC and VAS clinical sings did not show a significant difference in patients with and without CVD. The time average value of DAS28 (ESR) during the study period was significantly higher in patients with CVD (3.7 vs. 3.39, p = 0.002) compared to those without CVD. DAS28 (CRP) shows the same trend. In patients with CVD, the time average value of the follow-up indicator was 3.21, and in patients without CVD, 2.88 (p <0.001). Conclusion: The results of this study, in PA patients conducting treatment with biological agents in the real life, outside of the clinical study conditions, demonstrate that independently of treatment, patients with CVD continue to maintain higher background inflammation. An optimization of therapeutic behavior in real life is necessary to improve the long-term prognosis of these patients.

scholarly journals Diagnostics of low-pressure capacitively coupled RF discharge argon plasma

2019 ◽  
Vol 13 (27) ◽  
pp. 76-82
Author(s):  
Kadhim A. Aadim
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Langmuir Probe ◽  
Gas Flow ◽  
Low Pressure ◽  
Gas Pressure ◽  
Rf Discharge ◽  
Electrode Gap ◽  
Probe Characteristic ◽  
Capacitively Coupled

Low-pressure capacitively coupled RF discharge Ar plasma has been studied using Langmuir probe. The electron temperature, electron density and Debay length were calculated under different pressures and electrode gap. In this work the RF Langmuir probe is designed using 4MHz filter as compensation circuit and I-V probe characteristic have been investigated. The pressure varied from 0.07 mbar to 0.1 mbar while electrode gap varied from 2-5 cm. The plasma was generated using power supply at 4MHz frequency with power 300 W. The flowmeter is used to control Argon gas flow in the range of 600 standard cubic centimeters per minute (sccm). The electron temperature drops slowly with pressure and it's gradually decreased when expanding the electrode gap. As the gas pressure increases, the plasma density rises slightly at low gas pressure while it drops little at higher gas pressure. The electron density decreases rapidly with expand distances between electrodes.

Spectroscopic Study and Amorphous Film Deposition in RF and Pulsed Plasma Processings

1988 ◽  
Vol 117 ◽  
Author(s):  
Kenji Ebihara ◽  
Seiji Kanazawa ◽  
Sadao Maeda
Keyword(s):  
Processing System ◽  
Optical Emission ◽  
Quantitative Relationship ◽  
Amorphous Film ◽  
Film Deposition ◽  
Rf Discharge ◽  
Pulsed Plasma ◽  
Plasma Parameters ◽  
Optical Emission Spectrum ◽  
Plasma State

AbstractProcessing plasmas generated by three types of discharges are diagnosed spectroscopically in order to estimate the quantitative relationship between plasma parameters and electrical and optical properties of deposited materials. An rf discharge is capacitively produced by a 13.56 MHz rf oscillator. A microwave generator operating at 2.45 GHz is used to supply power to a discharge cavity. Further a pulsed plasma which is inductively generated by pulsed current ( 70 kA peak ) is applied to study dissociation process in the transient plasma and possibility of a novel processing system. The gases used are methane for amorphous carbon formation and silane for amorphous silicon deposition. Measurements of optical emission spectrum are performed to estimate the processing plasma state by the relative spectral intensity method and the Doppler-broadening method.

Methods for Reducing a Large Number of Current Profiles to a Small Subset for Riser VIV Analysis

2005 ◽  
Author(s):  
Kostas F. Lambrakos ◽  
Djoni E. Sidarta ◽  
Hugh M. Thompson ◽  
Atle Steen ◽  
Roger W. Burke
Keyword(s):  
Fatigue Damage ◽  
Average Power ◽  
Small Subset ◽  
Large Set ◽  
Computationally Efficient ◽  
Excitation Mode ◽  
Average Value ◽  
Vortex Induced Vibrations ◽  
Simplified Procedure

The paper presents two different approaches to construct subsets of current profiles from a large set of long term current profiles for the purpose of performing calculations for riser fatigue damage from vortex induced vibrations (VIV). The subsets are intended to reproduce the fatigue damage from the full set of current profiles. In the first approach, the full set of profiles is first sorted into bins based on current magnitude, direction and shear in the profile. The profiles within each bin are then reduced to a single constructed profile through one of many possible current averaging schemes. The present study includes two types of constructed profiles; one profile is generated by the average value of the currents for each bin and the other by the average value plus one standard deviation. The second approach is based on first performing a simplified and computationally efficient VIV analysis of the full set of profiles. The profiles are then sorted into bins by the dominant excitation mode, and then a single profile is chosen to represent all the profiles that excite the mode of interest. The chosen profile for the mode of interest has VIV power-in which is close to the average power-in for all the profiles that excite the mode. The number of profiles in the subset is equal to the number of modes that are excited by the full set of profiles. The VIV power-in in this paper is estimated through a simplified procedure that is consistent with the SHEAR7 methodology. Other available codes can also be used for the simplified VIV calculations.

Factor Analysis as a Complement to Band Resolution Techniques. III. Self Association in Trichloroacetic Acid

1975 ◽  
Vol 53 (9) ◽  
pp. 1251-1257 ◽  
Author(s):  
J. T. Bulmer ◽  
H. F. Shurvell
Keyword(s):  
Factor Analysis ◽  
Infrared Spectra ◽  
Trichloroacetic Acid ◽  
Linear Polymers ◽  
Carbonyl Groups ◽  
Absorption Coefficients ◽  
Average Value ◽  
Self Association ◽  
Shape Ratio ◽  
Monomer Band

Digitized infrared spectra of nine solutions of trichloroacetic acid in CCl4 have been studied in the carbonyl stretching region. At all concentrations only two bands are visually apparent. However, factor analysis indicates the presence of four absorbing components. The contour resolution technique gives a monomer band at 1786 cm−1, a dimer band at 1749 cm−1, and a third band close to the dimer frequency at approximately 1735 cm−1. Examination of the changes in Cauchy–Gauss shape ratio of the monomer band with increasing concentration indicates the presence of an unresolved component. The band at 1735 cm−1 and the unresolved band near the monomer peak at 1786 cm−1 are assigned to absorption of carbonyl groups in linear polymers of trichloroaceticacid. The monomer–dimer equilibrium constant was calculated from the molar absorption coefficients and absorbances of monomer and dimer bands. The average value over the concentration range 0.305 × 10−3 to 0.1603 M was 287 l/mol at 33.9 ± 0.5 °C.

scholarly journals Experimental analysis of Scheffler reflector water heater

2011 ◽  
Vol 15 (3) ◽  
pp. 599-604 ◽  
Author(s):  
Rupesh Patil ◽  
Gajanan Awari ◽  
Mahendra Singh
Keyword(s):  
Storage Tank ◽  
Large Diameter ◽  
Average Power ◽  
Water Heater ◽  
Average Value ◽  
Water Boiling Test ◽  
Maximum Water Temperature ◽  
Maximum Water ◽  
Set Up ◽  
And Storage

The performance of Scheffler reflector has been studied. In this system storage reservoir was installed at Focus point. It has a single large diameter drum which serves the dual purpose of absorber tube and storage tank. The drum is sized to have a storage capacity of 20 liter for experiment. The tests were carried out with this set up and were repeated for several days. Performance analysis of the collector has revealed that the average power and efficiency in terms of water boiling test to be 1.30 kilowatts and 21.61 % respectively against an average value of beam radiations of 742[Wm-2]. The maximum water temperature in the storage tank of 98?C has been achieved on a clear day operation and ambient temperature between 28?C to 31?C.

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