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Vincent M Donnelly - One of the best experts on this subject based on the ideXlab platform.
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measurement of electron temperatures and electron energy distribution functions in dual frequency capacitively coupled cf4 o2 plasmas using trace rare gases Optical Emission Spectroscopy
Journal of Vacuum Science and Technology, 2009Co-Authors: Zhiying Chen, Vincent M Donnelly, Demetre J Economou, Lee Chen, Merritt Funk, Radha SundararajanAbstract:Measurements of electron temperatures (Te) and electron energy distribution functions (EEDFs) in a dual frequency capacitively coupled etcher were performed by using trace rare gas Optical Emission Spectroscopy (TRG-OES). The parallel plate etcher was powered by a high frequency (60 MHz) “source” top electrode and a low frequency (13.56 MHz) “substrate” bottom electrode. Te first increased with pressure up to ∼20 mTorr and then decreased at higher pressures. Increasing the bottom rf power resulted in higher electron temperatures. Electron temperatures in 90% CF4+10% O2 plasmas were similar to those in 80% CF4+20% O2 plasmas. EEDF exhibited bi-Maxwellian characteristics with enhanced high energy tail, especially at pressures >20 mTorr.
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plasma electron temperatures and electron energy distributions measured by trace rare gases Optical Emission Spectroscopy
Journal of Physics D, 2004Co-Authors: Vincent M DonnellyAbstract:This article reviews a spectroscopic method for extracting plasma electron temperatures and electron energy distributions: trace rare gases Optical Emission Spectroscopy. Specifically, traces of Ne, Ar, Kr, and Xe are added to the plasma and the intensities of Emissions from the Paschen 2p levels are recorded. Intensities are also computed from a model that includes direct excitation from the ground state, as well as two-step excitation through the 3P2, and 3P0 metastable levels. A Maxwellian electron energy distribution function (EEDF), described by an electron temperature (Te), is assumed, and Te is extracted from the best match between the observed and calculated relative Emission intensities. By choosing Emission from specific sets of levels, the range of electron energies effective in exciting Emission can be selected and various portions of the EEDF can be investigated. Accurate measurement of Te depends critically on accurate cross sections for electron impact excitation, and hence a large portion of this article is devoted to a critical review of this subject. Improving on previous treatments, the model for computing Emission intensities and electron temperatures includes a complete analysis of the complex excitation and de-excitation of the metastable levels. Previous measurements of Te and EEDFs in chlorine and oxygen inductively coupled plasmas are re-evaluated with the current model. In general, the current version of the model yields similar results; specific differences are discussed.
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spatially resolved electron temperatures species concentrations and electron energy distributions in inductively coupled chlorine plasmas measured by trace rare gases Optical Emission Spectroscopy
Journal of Applied Physics, 2002Co-Authors: Vincent M Donnelly, M J SchabelAbstract:Determining the spatial dependence of charged and neutral species concentrations and energies in inductively coupled plasmas (ICP) is important for understanding basic plasma chemistry and physics, as well as for optimizing the placement of the wafer with respect to the ICP source to maximize properties such as etching rate uniformity, while minimizing charging-induced damage and feature profile anomalies. We have determined the line-integrated electron temperature (Te) and Cl-atom number density (nCl) as a function of the axial distance (z) from the wafer in a chlorine ICP, using trace rare gases Optical Emission Spectroscopy (TRG-OES). By selecting rare gas lines that are either (a) excited mostly from the ground states, or (b) excited mainly from the metastable states we were also able to obtain approximate electron energy distributions functions (EEDFs). The gap between the wafer and the window adjacent to the flat coil inductive source was fixed at 15 cm. The pressure was 2, 10, or 20 mTorr (95% Cl2,...
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determination of electron temperature atomic fluorine concentration and gas temperature in inductively coupled fluorocarbon rare gas plasmas using Optical Emission Spectroscopy
Journal of Vacuum Science and Technology, 2002Co-Authors: M J Schabel, Vincent M Donnelly, Avi Kornblit, W W TaiAbstract:Recent advances in the interpretation of Optical Emission spectra from plasmas have made it possible to measure parameters such as electron temperature (Te), relative electron density, and gas temperature (Tg) with this nonintrusive technique. Here we discuss the application of trace rare gas Optical Emission Spectroscopy (TRG-OES), Optical actinometry, and N2 rotational Spectroscopy to determine Te, relative electron density, fluorine atom concentration, and Tg for fluorocarbon/Ar plasmas in an inductively coupled reactor. Various etch processes, containing mixtures of a carrier gas, C2F6, and C4F8, were evaluated as a function of pressure and flowrate. Ar, Kr, and Ne were used individually or were mixed to comprise the carrier gas. In the case of TRG-OES and Optical Emission actinometry, a mixture containing equal parts of He, Ne, Ar, Kr, and Xe (∼1% ea.) was added. A method for correcting excitation cross sections is introduced for cases when radiation trapping affects the Emission of a rare gas (Ar) t...
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ultrahigh frequency versus inductively coupled chlorine plasmas comparisons of cl and cl2 concentrations and electron temperatures measured by trace rare gases Optical Emission Spectroscopy
Journal of Applied Physics, 1998Co-Authors: M V Malyshev, Vincent M Donnelly, Seiji SamukawaAbstract:Using trace rare gases Optical Emission Spectroscopy, Cl and Cl2 number densities (nCl and nCl2) and electron temperatures (Te) were measured for two source configurations of high-density chlorine plasmas. In one configuration, the reactor was outfitted with a spoke antenna, operated at a resonant ultrahigh frequency (UHF) of 500 MHz. Alternatively, the same reactor was configured with a single loop, inductively coupled plasma (ICP) source operated at a radio frequency of 13.56 MHz. Optical Emission from trace amounts (1% each) of rare gases added to the main Cl2 feed gas were recorded as a function of power and pressure. Modeling was used to derive Te from these data. Additional Emission from Cl2 (at 3050 A) and Cl (numerous lines between 7000 and 9000 A), normalized to the appropriate Emission from the rare gases (i.e., actinometry) was used to obtain nCl2 and nCl. In the ICP plasma, Te decreased monotonically from 5.5 to 1.2 eV as a function of increasing pressure between 1 and 20 mTorr. Conversely, wi...
M J Schabel - One of the best experts on this subject based on the ideXlab platform.
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spatially resolved electron temperatures species concentrations and electron energy distributions in inductively coupled chlorine plasmas measured by trace rare gases Optical Emission Spectroscopy
Journal of Applied Physics, 2002Co-Authors: Vincent M Donnelly, M J SchabelAbstract:Determining the spatial dependence of charged and neutral species concentrations and energies in inductively coupled plasmas (ICP) is important for understanding basic plasma chemistry and physics, as well as for optimizing the placement of the wafer with respect to the ICP source to maximize properties such as etching rate uniformity, while minimizing charging-induced damage and feature profile anomalies. We have determined the line-integrated electron temperature (Te) and Cl-atom number density (nCl) as a function of the axial distance (z) from the wafer in a chlorine ICP, using trace rare gases Optical Emission Spectroscopy (TRG-OES). By selecting rare gas lines that are either (a) excited mostly from the ground states, or (b) excited mainly from the metastable states we were also able to obtain approximate electron energy distributions functions (EEDFs). The gap between the wafer and the window adjacent to the flat coil inductive source was fixed at 15 cm. The pressure was 2, 10, or 20 mTorr (95% Cl2,...
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determination of electron temperature atomic fluorine concentration and gas temperature in inductively coupled fluorocarbon rare gas plasmas using Optical Emission Spectroscopy
Journal of Vacuum Science and Technology, 2002Co-Authors: M J Schabel, Vincent M Donnelly, Avi Kornblit, W W TaiAbstract:Recent advances in the interpretation of Optical Emission spectra from plasmas have made it possible to measure parameters such as electron temperature (Te), relative electron density, and gas temperature (Tg) with this nonintrusive technique. Here we discuss the application of trace rare gas Optical Emission Spectroscopy (TRG-OES), Optical actinometry, and N2 rotational Spectroscopy to determine Te, relative electron density, fluorine atom concentration, and Tg for fluorocarbon/Ar plasmas in an inductively coupled reactor. Various etch processes, containing mixtures of a carrier gas, C2F6, and C4F8, were evaluated as a function of pressure and flowrate. Ar, Kr, and Ne were used individually or were mixed to comprise the carrier gas. In the case of TRG-OES and Optical Emission actinometry, a mixture containing equal parts of He, Ne, Ar, Kr, and Xe (∼1% ea.) was added. A method for correcting excitation cross sections is introduced for cases when radiation trapping affects the Emission of a rare gas (Ar) t...
Peng Wang - One of the best experts on this subject based on the ideXlab platform.
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helium retention depth profile in plasma facing materials measured by glow discharge Optical Emission Spectroscopy
Spectrochimica Acta Part B: Atomic Spectroscopy, 2021Co-Authors: Li Qiao, Xuexi Zhang, Hong Zhang, Peng WangAbstract:Abstract In order to quantitatively study the retention behaviors of helium (He) in the fusion relevant materials by Glow Discharge - Optical Emission Spectroscopy (GD-OES), tungsten (W) and copper (Cu) samples were implanted by He ions with different energies and fluences, and the He distributions in these samples were investigated by transmission electron microscopy (TEM) and simulated by the Stopping and Range of Ions in Matter (SRIM). After that these He implanted samples were used as calibration samples, and the electrical signal of GD-OES measurement was converted to He concentration depth profile. The results show that TEM investigations are consistent with SRIM simulation at the maximum concentration distribution depth of He. The experiment also found that He diffusion in the material is obvious, beyond the prediction range of SRIM simulation. After calibration, the He depth profiles in multi-energy implantation W, Cu and EUROFER97 samples measured by GD-OES agree with the SRIM simulation. GD-OES and thermal desorption Spectroscopy (TDS) independent experiments proved that the total retained He amounts in materials are close to the total implanted He amounts, indicating that using He-implanted standard samples combined with SRIM simulation to obtain GD-OES depth profile is reliable.
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experimental measurement of deuterium concentration and depth profiling in tungsten by radio frequency glow discharge Optical Emission Spectroscopy
Spectrochimica Acta Part B: Atomic Spectroscopy, 2020Co-Authors: Li Qiao, Xuexi Zhang, Hong Zhang, Peng WangAbstract:Abstract For a detailed understanding of fuel retention characterization, especially in-depth profile analysis of plasma-facing materials, radio frequency glow discharge Optical Emission Spectroscopy (RF-GDOES) method was applied to determine the deuterium depth concentration. Tungsten or titanium targets were co-deposited in deuterium atmosphere by magnetron sputtering, and these deposited films with different deuterium contents and film thicknesses were used as the standard samples for RF-GDOES measurement. Rutherford backscattering Spectroscopy (RBS) and thermal desorption mass spectrometry (TDS) were used to measure the metal and deuterium concentrations in the standard films, respectively. After the standardization of deuterium concentration and sample sputtering rate when tested by RF-GDOES, deuterium concentration and depth profiling of deuterium-exposed tungsten samples were obtained and subsequently verified by compared with results by TDS. Results showed the deuterium concentration in deuterium-exposed tungsten has a high concentration peak about 0.002–0.013 at.fr . within 125 nm near-surface, and then reduced by two orders of magnitude from surface to depth with a minimum concentration of few 10−5 at.fr .. With increasing the incident deuterium fluence, deuterium concentration increased obviously in the first 6 μm near the surface. Under low incident fluence, the total released deuterium amounts obtained from RF-GDOES and TDS methods agree within the experimental error. However, the total released deuterium amounts measured by RF-GDOES were smaller than those of the TDS method under high fluence due to reason of the increasing diffusion depth and inhomogeneity of deuterium in tungsten.
J M Albella - One of the best experts on this subject based on the ideXlab platform.
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modelling of glow discharge Optical Emission Spectroscopy depth profiles of metal cr ti multilayer coatings
Spectrochimica Acta Part B: Atomic Spectroscopy, 2008Co-Authors: Escobar R Galindo, J M AlbellaAbstract:Abstract The broadening effects found in the depth profiles of abrupt periodic multilayers obtained by Glow Discharge Optical Emission Spectroscopy (GDOES) have been modelled by assuming that the resulting absolute concentration profiles can be described by Gaussian functions of constant area (equal to that of the cross section of the individual layers) and decreasing amplitude. The full width at half maximum (FWHM) of these functions has been assumed to increase with depth z according to a power law of the type: FWHM ( z ) = a + bz c , using for a and c , values estimated from previous works. In this model, the parameter b , defining the broadening and degradation of the layer interfaces, is obtained by fitting the experimental profiles with the theoretical spectra. We have found a correlation between b and the erosion rate of the material layers. In general, the model properly describes the depth profiles of multilayer structures made of alternating Ti and Cr layers in the nanometre range, and can be an useful tool to explain the profiles of more complex systems.
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nanometric resolution in glow discharge Optical Emission Spectroscopy and rutherford backscattering spectrometry depth profiling of metal cr al nitride multilayers
Spectrochimica Acta Part B: Atomic Spectroscopy, 2006Co-Authors: Escobar R Galindo, R Gago, E Fornies, A Munozmartin, Climent A Font, J M AlbellaAbstract:Abstract In this work, we address the capability of glow discharge Optical Emission Spectroscopy (GDOES) for fast and accurate depth profiling of multilayer nitride coatings down to the nanometer range. This is shown by resolving the particular case of CrN/AlN structures with individual thickness ranging from hundreds to few nanometers. In order to discriminate and identify artefacts in the GDOES depth profile due to the sputtering process, the layered structures were verified by Rutherford backscattering spectrometry (RBS) and scanning electron microscopy (SEM). The interfaces in the GDOES profiles for CrN/AlN structures are sharper than the ones measured for similar metal multilayers due to the lower sputtering rate of the nitrides. However, as a consequence of the crater shape, there is a linear degradation of the depth resolution with depth (approximately 40 nm/μm), saturating at a value of approximately half the thickness of the thinner layer. This limit is imposed by the simultaneous sputtering of consecutive layers. The ultimate GDOES depth resolution at the near surface region was estimated to be of 4–6 nm.
A De Giacomo - One of the best experts on this subject based on the ideXlab platform.
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experimental characterization of metallic titanium laser induced plasma by time and space resolved Optical Emission Spectroscopy
Spectrochimica Acta Part B: Atomic Spectroscopy, 2003Co-Authors: A De GiacomoAbstract:Abstract Time and space resolved Optical Emission Spectroscopy has been successfully employed to investigate the evolution of the plasma produced by the interaction of UV laser beam with a metallic target of titanium at two different pressures (10 −5 and 3.4×10 −2 torr) and at distances up to 3 mm from the target. By time of flight measurements and Boltzmann plots both the dynamic and the kinetic aspects have been discussed. The quasi-equilibrium state of the laser-induced plasma has been established on the basis of the failure of Saha balance equation. The effect of three-body recombination on atomic titanium temporal distribution has been explained. Temporal evolution of electron number density, as determined by Stark effect, has been used for the estimation of the three-body recombination rate constant.