Electron cross section set for CHF3

Morgan, W. L.; Winstead, Carl; McKoy, Vincent

doi:10.1063/1.1382833

Cited by 34 publications

(34 citation statements)

References 40 publications

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“…Although the two-term approximation worked well in CHF 3 swarm analysis, 29 here we are working with values of E/N approximately ten times the values used in that work. A similar situation can be found in swarm analyses of electrons in SF 6 .…”

Section: Discussion Of the Two-term Expansionmentioning

confidence: 99%

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Electron transport properties and collision cross sections in C2F4

Yoshida

Goto

Tagashira

et al. 2002

Journal of Applied Physics

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We have measured the electron drift velocity, longitudinal diffusion coefficient, and ionization coefficient in tetrafluoroethene (C2F4). Using these data and the results of ab initio calculations of the elastic, momentum-transfer, and neutral-excitation cross sections, along with measurements of the partial ionization cross sections, we have performed a swarm analysis in order to construct a self-consistent set of electron impact cross sections for C2F4. The swarm analysis consists of solutions to Boltzmann’s equation for electrons in C2F4 for values of E/N⩽500 Td and direct Monte Carlo simulation of electron transport in C2F4 for 500 Td⩽E/N⩽2000 Td. We present an analysis and discussion of the sensitivity of cross sections derived from swarm data to uncertainties in the electron transport measurements. We also discuss the failure of the two-term spherical harmonic solution to Boltzmann’s equation for E/N>500 Td, which necessitated the use of Monte Carlo simulations for high values of E/N.

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Section: Discussion Of the Two-term Expansionmentioning

confidence: 99%

“…29 This approach gave unrealistic results for the excitation cross sections, so we returned to the more sophisticated approach of adjusting both the energy dependencies and the magnitudes of the cross sections.…”

Section: Boltzmann's Equation and The Downhill Simplexmentioning

confidence: 99%

Electron transport properties and collision cross sections in C2F4

Yoshida

Goto

Tagashira

et al. 2002

Journal of Applied Physics

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“…In this regard we note the comprehensive data compilations from Christophorou et al 21 and Christophorou and Olthoff, 22 and the theoretical elastic scattering computations from Natalense et al, 23,24 Dimiz et al, 25 Morgan et al, 26 Varella et al, 27 and Iga et al 28 The work of Morgan et al also contained an electron-swarm analysis of the Schwinger multichannel computation results, while significant experimental results, from 1.5-30 eV, are contained in Varella et al 27 and, from 20-500 eV, in Iga et al 28 We also note additional experimental results from Meier et al 29 and Tanaka et al 30 In general, we find very good agreement between the data of Varella et al 27 and Tanaka et al, 30 when they are compared with the DCSs from Iga et al 28 at each common energy. As a consequence, our recommended data in Table 13 and Fig.…”

Section: Chfmentioning

confidence: 99%

Elastic Cross Sections for Electron Collisions with Molecules Relevant to Plasma Processing

Yoon

Song

Kato

et al. 2010

Journal of Physical and Chemical Reference Data

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Absolute electron-impact cross sections for molecular targets, including their radicals, are important in developing plasma reactors and testing various plasma processing gases. Low-energy electron collision data for these gases are sparse and only the limited cross section data are available. In this report, elastic cross sections for electron-polyatomic molecule collisions are compiled and reviewed for 17molecules relevant to plasma processing. Elastic cross sections are essential for the absolute scale conversion of inelastic cross sections, as well as for testing computational methods. Data are collected and reviewed for elastic differential, integral, and momentum transfer cross sections and, for each molecule, the recommended values of the cross section are presented. The literature has been surveyed through early 2010.

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“…Summed cross sections for electronic excitation of CHF 3 , from Ref. [13]. comparison with experimental values obtained by Tanaka et al [24].…”

Section: C-c 4 Fmentioning

confidence: 99%

“…To aid in developing an electron cross section set for CHF 3 [13], we used the parallel SMC method described earlier to carry out calculations of the elastic cross section (differential, integral, and momentum transfer) as well as of the electron-impact exci-tation cross sections for several low-lying electronic states. In addition to these collision calculations, we carried out ancillary studies of fragmentation energetics and of the dissociative behavior of some of the excited states using standard quantum chemistry methodology.…”

Section: Chfmentioning

confidence: 99%

Developing Cross Section Sets for Fluorocarbon Etchants

Winstead¹,

McKoy²

2002

AIP Conference Proceedings

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Abstract. Successful modeling of plasmas used in materials processing depends on knowledge of a variety of collision cross sections and reaction rates, both within the plasma and at the surface. Electron-molecule collision cross sections are especially important, affecting both electron transport and the generation of reactive fragments by dissociation and ionization. Because the supply of cross section data is small and measurements are difficult, computational approaches may make a valuable contribution, provided they can cope with the significant challenges posed. In particular, a computational method must deal with the full complexity of low-energy electronmolecule interactions, must treat polyatomic molecules, and must be capable of computing cross sections for electronic excitation. These requirements imply that the method will be numerically intensive and thus must exploit high-performance computers to be practical. We have developed an ab initio computational method, the Schwinger multichannel (SMC) method, that possesses the characteristics just described, and we have applied it to compute cross sections for a variety of molecules, with particular emphasis on fluorocarbon and hydrofluorocarbon etchants used in the semiconductor industry. A key aspect of this work has been an awareness that cross section sets, validated when possible against swarm data, are more useful than individual cross sections. To develop such sets, cross section calculations must be integrated within a focused collaborative effort. Here we describe electron cross section calculations carried out within the context of such a focused effort, with emphasis on fluorinated hydrocarbons including CHF 3 (trifluoromethane), c-C 4 F 8 (octafluorocyclobutane), and C 2 F 4 (tetrafluoroethene).

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Electron cross section set for CHF3

Cited by 34 publications

References 40 publications

Electron transport properties and collision cross sections in C2F4

Electron transport properties and collision cross sections in C2F4

Elastic Cross Sections for Electron Collisions with Molecules Relevant to Plasma Processing

Developing Cross Section Sets for Fluorocarbon Etchants

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