Effects of impedance matching network on the discharge mode transitions in a radio-frequency inductively coupled plasma

Abstract

In inductively coupled plasma sources, discharge transitions from electrostatic mode (E mode) to electromagnetic mode (H mode) and from H mode to E mode occur. In previous studies, only a few works paid attention to the effects of the impedance matching network. Cunge et al. [Plasma Sources Sci. Technol. 8, 576 (1999)] investigated the E-H and H-E mode transitions under two different impedance matching situations, but no physical mechanism or interpretation was presented. This issue is remained to be systematically and quantitatively investigated, and the underlying mechanism to be unveiled. In this paper, the effects of the impedance matching network were experimentally studied in electropositive argon gas by varying the series capacitance in an inversely L-shaped matching network. The positive and negative feedback regions are established according to the effect of varying the series capacitance on the output power of the rf power supply. It was found that under the same experimental parameters, the discharge mode transitions are apt to be discontinuous and continuous in the positive and negative feedback regions, respectively. In addition, the critical coil rf current (or applied power) at the mode transition, the hysteretic loop width, and the difference in applied power during the discharge mode transition vary with the series capacitance. The critical coil rf current at the E-H mode transition is not always higher than that at the H-E mode transition.

Electron energy flux control using dual power in side-type inductively coupled plasma

“…The drastic increase in the center density is partly expected by the E to H transition in ICP. [14][15][16] In ICP, the power can be coupled to the plasma capacitively (E-mode) or inductively (H-mode), depending on the plasma density. The ICP operates in E mode at low plasma density, and more than proper density is required for the transition to Hmode.…”

Evolution of the electron energy distribution and E-H mode transition in inductively coupled nitrogen plasma

“…Seo et al 3 confirmed that a decrease in the plasma potential is a good indicator of the E-H transition. The effect of the impedance matching network was studied by Daltrini et al 8 and Ding et al 9 Experiments were performed at a relatively low rf driving frequency by Ostrikov et al 10 and El-Fayoumi et al, 11 and at pulsed plasma by Edamur et al 12 Chung et al 13 and Singh et al 14 investigated electron energy distribution function ͑EEDF͒ measurements and their characteristics in the E mode.…”

Investigation of magnetic-pole-enhanced inductively coupled nitrogen-argon plasmas

“…Experimentally, decrease in plasma potential during E/H transition was confirmed by Seo et al 3 Singh et al 4 and Chung et al 5 studied the behaviour and measurement of electron energy distribution function in E mode. The effect of impedance matching network in ionised low pressure ICPs was reported by Ding et al 6 and Daltrini et al 7 Low RF frequency measurements were reported by El-Fayoumi et al 8 and Ostrikov et al 9 and at pulsed plasma by Edamur et al 10 Some theoretical works were also carried out to study E/H mode transition. The critical current for the operation of stable H mode was calculated by Kortshagen et al 11 and skin depth by Lee et al 12 Turner et al 13 and Cunge et al 14 considered the E-H transition mechanism and hysteresis based on the balance equation and the nonlinear effects most notably between power absorptions and power dissipations.…”