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Determination of atomic oxygen state densities in a double inductively coupled plasma using optical emission and absorption spectroscopy and probe measurements
摘要： A collisional radiative model for fast estimation and monitoring of atomic oxygen ground and excited state densities and ?uxes in varying Ar:O2 mixtures is developed and applied in double inductively coupled plasma source at a pressure of 5 Pa and incident power of 500 W. The model takes into account measured line intensities of 130.4 nm, 135.6 nm, 557.7 nm, and 777.5 nm, the electron densities and electron energy distribution functions determined using a Langmuir probe and multipole resonance probe as well as the state densities of the ?rst four excited states of argon measured with the branching fraction method and compared to tunable diode laser absorption spectroscopy. The in?uence of cascading and self absorption is included and the validity of the used cross sections and reaction rates is discussed in detail. The determined atomic oxygen state densities are discussed for their plausibility, sources of error, and compared to other measurements. Furthermore, the results of the model are analyzed to identify the application regimes of much simpler models, which could be used more easily for process control, e.g. actinometry.
关键词： absorption spectroscopy,atomic oxygen,probe measurements,collisional radiative model,optical emission spectroscopy
更新于2025-09-19 17:13:59
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Calculation of the extreme-ultraviolet radiation conversion efficiency for a laser-produced tin plasma source
摘要： This article presents the calculation results on the conversion efficiency (CE) of 1.064 μm laser-produced plasmas (LPPs) extreme-ultraviolet (EUV) tin (Sn) light sources with the Gaussian and a triangular-flat-topped like laser pulse temporal shapes. The computational model includes a collisional-radiative model and 1D hydrodynamics code that predicts reported experimental and theoretical results on the CE of 1.064 μm and 10.6 μm LPP EUV sources with the planar and mass-limited spherical Sn targets. The calculations for the case of a spherical target reveal that an optimum triangular-flat-topped like laser pulse generates a higher CE compared to the Gaussian pulse, especially, for the longer laser pulse duration than ~30 ns. The study demonstrated that a rising intensity rate of the laser pulse has a vital role to optimize the CE as well as to prolong the in-band (13.5 ± 0.135 nm) spectral emission of a small Sn spherical target. The model predicts a ~30 ns rising time duration for a linearly increasing intensity of triangular-flat-topped 1.064 μm laser pulse is necessary to obtain a maximum CE with a typical ~40 μm diameter liquid Sn droplet.
关键词： Extreme-ultraviolet lithography,Collisional-radiative model,Laser-produced plasmas,Radiation-hydrodynamics,Highly-charged tin spectra
更新于2025-09-19 17:13:59
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Optical diagnostics of helium recombining plasmas with collisional radiative model
摘要： Optical diagnostics for plasmas has many advantages that allow for the determination and understanding of plasma parameters. A method employing the line intensity ratio (LIR), combined with the collisional-radiative (CR) model considering the radiation trapping effect (RTE), was developed to analyze the recombining helium plasmas. The recombining plasma component and the ionizing plasma components in the He CR-model were evaluated, and the RTEs for from the ground state to n1P states were analyzed. The electron temperature and density of the helium recombining plasmas were determined using seven LIRs with the He CR-model, considering the RTEs of 11S–31P, 11S–41P, and 11S–51P. When the He gas pressure was above 100 mTorr, the electron temperature was less than 0.8 eV and the electron density was more than 1012 cm?3. The determined plasma parameters were compared with those obtained by the continuum method and in reasonable agreement with those by the continuum method.
关键词： helium recombining plasmas,optical diagnostics,collisional radiative model,radiation trapping effect,line intensity ratio
更新于2025-09-10 09:29:36
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Collisional - radiative model of xenon plasma with calculated electron impact fine-structure excitation cross sections
摘要： Detailed electron impact excitation cross section results for xenon in the wide range of incident energy from threshold to 1000eV are calculated using relativistic distorted wave (RDW) theory. Various transitions from the ground 5p6 state to the excited 5p56s, 5p56p, 5p55d, 5p57s and 5p57p as well as among these excited states are considered. The relativistic Dirac-Fock multi-configuration wave functions for the ground and excited states of the xenon are obtained and used in the calculations. Where available our cross section results are compared with previously reported measurements and calculations. We have also fitted the calculated cross sections through analytical formulae for plasma modeling purposes. As an application, using the obtained cross sections, a collisional Radiative (C-R) model coupled with an optical emission measurement from the inductively coupled Xe plasma is developed and the extracted plasma parameters are reported.
关键词： relativistic distorted wave theory,Electron impact excitation,cross-sections,collisional radiative model
更新于2025-09-04 15:30:14