Development of a Radiofrequency Plasma Diagnostic System with a Langmuir Probe and Study of a Capacitively Coupled Argon Plasma

2011 ◽  
Vol 227 ◽  
pp. 204-207 ◽  
Author(s):  
Djelloul Mendil ◽  
Hadj Lahmar ◽  
Djamel Ouadjaout ◽  
Laid Henni ◽  
Laïfa Boufendi ◽  
...  

A single rf-compensated cylindrical Langmuir probe has been developed in order to characterise a plasma RF discharge. A circuit using radiofrequency filtering and the passive compensation method was employed to minimize the probe curve distortions. The effect of the rfcompensation on the probe measurements was discussed. The latter were performed at power and pressure of 50 W and 510-2–1.2 mbar, respectively. Compensated measurements of the electron energy distribution function (EEDF) and plasma parameters were conducted at powers ranging from 5 to 120 W and pressure of 0.3 mbar. They exhibit a transition between the stochastic electron heating mode operating at low powers and the secondary-electron emission heating mode (γ) operating at high powers. The electronic density increases from 1.5×109 to 3.2×1010 cm-3 while the effective electron temperature decreases from 3.7 to 2.3 eV. The EEDFs were found to be Druyvesteyn-like in the range of 5–80W and then evolve to the Maxwellian beyond 90W.

2005 ◽  
Vol 76 (1) ◽  
pp. 013505 ◽  
Author(s):  
P. Sicard ◽  
C. Boucher ◽  
A. Litnovsky ◽  
J.-P. St-Germain

1972 ◽  
Vol 27 (10) ◽  
pp. 1425-1433 ◽  
Author(s):  
F. Howorka ◽  
M. Pähl

Abstract The negative glow plasma of a cylindrical hollow cathode dc discharge (0.05 - 1 Torr Argon, 1-30 mA) is investigated as to the position of the glow edge, the axial dependence of the cathode current density, the axial and radial potential distributions, the density and energy of electrons (from Langmuir probe measurements) as dependent on pressure, discharge current and position, etc. It is found that two groups of electrons exist whose energies are < 0.5 eV ~ 3 eV and the ratio of their denisties being 3 up to 20. A phenomenological explanation is given for the relatively high denisty of the fast group, The results are compared with those of other auhors concerning hollow-cathode and linear discharges.


2021 ◽  
pp. 163-170
Author(s):  
Y.V. Siusko ◽  
Yu.V. Kovtun

A brief review of the main microwave diagnostics methods of inhomogeneous plasma based on the refraction of microwaves is given. These methods make it possible to determine the plasma density distribution, the magnetic field distribution, the electron collision frequency, and the electron temperature profile. In addition, the determination of the average density of the peripheral plasma layers and the local inhomogeneities of the rotating plasma are also possible. The effect of refraction on the accuracy of determining the plasma parameters by using microwave methods for plasma diagnostics is considered.


2019 ◽  
Vol 13 (27) ◽  
pp. 76-82
Author(s):  
Kadhim A. Aadim

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.


Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2147
Author(s):  
Žiga Gosar ◽  
Janez Kovač ◽  
Denis Đonlagić ◽  
Simon Pevec ◽  
Gregor Primc ◽  
...  

An extremely asymmetric low-pressure discharge was used to study the composition of thin films prepared by PECVD using HMDSO as a precursor. The metallic chamber was grounded, while the powered electrode was connected to an RF generator. The ratio between the surface area of the powered and grounded electrode was about 0.03. Plasma and thin films were characterised by optical spectroscopy and XPS depth profiling, respectively. Dense luminous plasma expanded about 1 cm from the powered electrode while a visually uniform diffusing plasma of low luminosity occupied the entire volume of the discharge chamber. Experiments were performed at HMDSO partial pressure of 10 Pa and various oxygen partial pressures. At low discharge power and small oxygen concentration, a rather uniform film was deposited at different treatment times up to a minute. In these conditions, the film composition depended on both parameters. At high powers and oxygen partial pressures, the films exhibited rather unusual behaviour since the depletion of carbon was observed at prolonged deposition times. The results were explained by spontaneous changing of plasma parameters, which was in turn explained by the formation of dust in the gas phase and corresponding interaction of plasma radicals with dust particles.


1992 ◽  
Author(s):  
A. T. Young ◽  
D. A. Bachman ◽  
P. Chen ◽  
K. N. Leung ◽  
C. Y. Li ◽  
...  

1988 ◽  
Vol 117 ◽  
Author(s):  
Kenji Ebihara ◽  
Seiji Kanazawa ◽  
Sadao Maeda

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.


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