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Title: Bias formation in a pulsed radiofrequency argon discharge

Abstract

A one dimensional (1D) particle-in-cell (PIC) computer simulation has been used in conjunction with a small experimental plasma reactor, to investigate the effects of pulsing on a low pressure, capacitively coupled, rf argon plasma. In particular this article investigates the time-constants involved in the development and evolution of the bias voltage in asymmetric reactor geometry. Surprisingly, the charging time for the blocking capacitor does not occur on electron time scales, but is influenced primarily by the ambipolar drift of ions to the earthed electrode. It is shown that following plasma breakdown there is a net current flow in the system which charges the blocking capacitor in the external matching circuit and produces the bias voltage. Both the PIC simulation and the experimental measurements show that a net current flow is produced by a delay in the onset of the electron current to the earthed electrode, which is correlated to the charging time of the capacitor. From the simulation it can be seen that during this period the plasma potential in the center of the discharge is higher than one would expect, preventing electrons from reaching the earthed electrode. {copyright} {ital 1997 American Institute of Physics.}

Authors:
; ;  [1];  [2]
  1. Space Plasma and Plasma Processing, Plasma Research Lab, RSPhysSE, The Australian National University, ACT 0200 (Australia)
  2. Nissin Electric Co., LTD., Research and Development Division, 47 Umezu-Takase-Cho, Ukyo-ku, Kyoto 615 (Japan)
Publication Date:
OSTI Identifier:
531733
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 82; Journal Issue: 2; Other Information: PBD: Jul 1997
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; HIGH-FREQUENCY DISCHARGES; PLASMA SIMULATION; PLASMA DIAGNOSTICS; ARGON; CAPACITANCE; AMBIPOLAR DIFFUSION; BREAKDOWN; PLASMA POTENTIAL; PLASMA DENSITY

Citation Formats

Smith, H B, Charles, C, Boswell, R W, and Kuwahara, H. Bias formation in a pulsed radiofrequency argon discharge. United States: N. p., 1997. Web. doi:10.1063/1.365615.
Smith, H B, Charles, C, Boswell, R W, & Kuwahara, H. Bias formation in a pulsed radiofrequency argon discharge. United States. doi:10.1063/1.365615.
Smith, H B, Charles, C, Boswell, R W, and Kuwahara, H. Tue . "Bias formation in a pulsed radiofrequency argon discharge". United States. doi:10.1063/1.365615.
@article{osti_531733,
title = {Bias formation in a pulsed radiofrequency argon discharge},
author = {Smith, H B and Charles, C and Boswell, R W and Kuwahara, H},
abstractNote = {A one dimensional (1D) particle-in-cell (PIC) computer simulation has been used in conjunction with a small experimental plasma reactor, to investigate the effects of pulsing on a low pressure, capacitively coupled, rf argon plasma. In particular this article investigates the time-constants involved in the development and evolution of the bias voltage in asymmetric reactor geometry. Surprisingly, the charging time for the blocking capacitor does not occur on electron time scales, but is influenced primarily by the ambipolar drift of ions to the earthed electrode. It is shown that following plasma breakdown there is a net current flow in the system which charges the blocking capacitor in the external matching circuit and produces the bias voltage. Both the PIC simulation and the experimental measurements show that a net current flow is produced by a delay in the onset of the electron current to the earthed electrode, which is correlated to the charging time of the capacitor. From the simulation it can be seen that during this period the plasma potential in the center of the discharge is higher than one would expect, preventing electrons from reaching the earthed electrode. {copyright} {ital 1997 American Institute of Physics.}},
doi = {10.1063/1.365615},
journal = {Journal of Applied Physics},
number = 2,
volume = 82,
place = {United States},
year = {1997},
month = {7}
}