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Title: Electron energy distributions and electron impact source functions in Ar/N 2 inductively coupled plasmas using pulsed power

ORCiD logo [1];  [1]
  1. Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109-2122, USA
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
Grant/Contract Number:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 4; Related Information: CHORUS Timestamp: 2018-02-15 01:59:03; Journal ID: ISSN 0021-8979
American Institute of Physics
Country of Publication:
United States

Citation Formats

Logue, Michael D., and Kushner, Mark J. Electron energy distributions and electron impact source functions in Ar/N 2 inductively coupled plasmas using pulsed power. United States: N. p., 2015. Web. doi:10.1063/1.4904935.
Logue, Michael D., & Kushner, Mark J. Electron energy distributions and electron impact source functions in Ar/N 2 inductively coupled plasmas using pulsed power. United States. doi:10.1063/1.4904935.
Logue, Michael D., and Kushner, Mark J. 2015. "Electron energy distributions and electron impact source functions in Ar/N 2 inductively coupled plasmas using pulsed power". United States. doi:10.1063/1.4904935.
title = {Electron energy distributions and electron impact source functions in Ar/N 2 inductively coupled plasmas using pulsed power},
author = {Logue, Michael D. and Kushner, Mark J.},
abstractNote = {},
doi = {10.1063/1.4904935},
journal = {Journal of Applied Physics},
number = 4,
volume = 117,
place = {United States},
year = 2015,
month = 1

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4904935

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Cited by: 2works
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  • In plasma materials processing, such as plasma etching, control of the time-averaged electron energy distributions (EEDs) in the plasma allows for control of the time-averaged electron impact source functions of reactive species in the plasma and their fluxes to surfaces. One potential method for refining the control of EEDs is through the use of pulsed power. Inductively coupled plasmas (ICPs) are attractive for using pulsed power in this manner because the EEDs are dominantly controlled by the ICP power as opposed to the bias power applied to the substrate. In this paper, we discuss results from a computational investigation ofmore » EEDs and electron impact source functions in low pressure (5–50 mTorr) ICPs sustained in Ar/N{sub 2} for various duty cycles. We find there is an ability to control EEDs, and thus source functions, by pulsing the ICP power, with the greatest variability of the EEDs located within the skin depth of the electromagnetic field. The transit time of hot electrons produced in the skin depth at the onset of pulse power produces a delay in the response of the EEDs as a function of distance from the coils. The choice of ICP pressure has a large impact on the dynamics of the EEDs, whereas duty cycle has a small influence on time-averaged EEDs and source functions.« less
  • The behavior of pulsed-power (square wave) modulated argon plasmas generated by an inductively coupled plasma (ICP) source is experimentally investigated. The apparatus is an ICP source with a flat coil geometry equipped with a cylindrical Langmuir probe on the axis of the cylindrical chamber. The evolution of the plasma density is determined from the wave forms of ion saturation currents. The rise and fall of the density had a time scale of a few tens of microseconds. The time average plasma density is also measured as a function of pulse frequency and duty ratio, holding the average absorbed power constant.more » When the plasma is modulated, the density is larger than that for a continuous wave excitation of the same average power. Larger densities are obtained for smaller duty ratios. The density increases monotonically as the period is decreased down to 100 {mu}s. This agrees qualitatively with the modeling result, which accounts for the higher density by the difference of time scales for the generation and the loss of charged particles. The results for electron temperature measurements also show good agreement with the model quantitatively during the pulse {open_quote}{open_quote}on{close_quote}{close_quote} times. If the period is long enough, it is found that the electron temperature rises abruptly at the initial stage of power application, in agreement with the calculation. {copyright} {ital 1996 American Vacuum Society}« less
  • The electron energy distribution function (EEDF) in a low-pressure inductively coupled plasma confined between two infinite plates separated by 10 cm is investigated using a one-dimensional particle-in-cell simulation including Monte Carlo collisions. At low pressure, where the electron mean free path is of the order of or greater than the system length, the EEDF is close to Maxwellian, except for its tail, depleted at high energy. We give clear evidence that this depletion is mostly due to the high-energy electrons escaping to the walls. As a result of the EEDF nonlocality, the break energy, for which the depletion of themore » Maxwellian starts, is found to track the plasma potential. At a higher pressure, the electron mean free paths of the various elastic and inelastic collisions become shorter than the system length, resulting in a loss of nonlocality and the break energy of the distribution function moves to energies lower than the plasma potential.« less
  • A global model was developed to investigate the densities of negative ions and the other species in a low-pressure inductively coupled hydrogen plasma with a bi-Maxwellian electron energy distribution. Compared to a Maxwellian plasma, bi-Maxwellian plasmas have higher populations of low-energy electrons and highly vibrationally excited hydrogen molecules that are generated efficiently by high-energy electrons. This leads to a higher reaction rate of the dissociative electron attachment responsible for negative ion production. The model indicated that the bi-Maxwellian electron energy distribution at low pressures is favorable for the creation of negative ions. In addition, the electron temperature, electron density, andmore » negative ion density calculated using the model were compared with the experimental data. In the low-pressure regime, the model results of the bi-Maxwellian electron energy distributions agreed well quantitatively with the experimental measurements, unlike those of the assumed Maxwellian electron energy distributions that had discrepancies.« less
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