Electrical characterization of an inductively coupled gaseous electronics conference reference cell

Abstract

Plasma parameters and particularly the external electrical operational parameters are examined with respect to mode transition and hysteresis. The external electrical parameters such as antenna current ͑I c ͒ and antenna voltage ͑V c ͒ amplitudes are measured after the matching network and discussed for an inductively coupled argon discharge. A wide range of discharge conditions by varying applied power ͑up to 150 W at 13.56 MHz͒, gas pressure ͑0.7-7.5 Pa͒, and electrostatic coupling strength are measured for a gaseous electronics conference radio frequency reference cell. The effect on the power coupling efficiency by varying electrostatic coupling strength is studied via implementing two distinct grounded Faraday shields, in addition to the original nonshielded condition. A brief discussion on the evolution of floating potential, plasma potential, electron density, and electron energy distribution function with power and pressure is also presented mainly in context to mode transitions and hysteresis. Relatively smooth transitions in the plasma parameters and in the external electrical parameters are measured close to H to E mode transition region. Contrary to plasma parameters, however, the reverse transition from E to H mode was found to be abrupt in external parameters. The plasma parameters are measured using a commercial Langmuir probe, whereas the antenna currents and voltages are measured using a homebuilt Rogowski coil and capacitor divider, respectively.

E‐H Transition in Argon/Oxygen Inductively Coupled RF Plasmas

“…From the slope in figure 4(b) one can calculate the inductance which is L II = 1.4 μH. This value is important for different numerical simulations and is comparable with the literature [26,30,43,46,48]. For the determination of the absorbed power P abs , the coil resistance R coil have to be determined [49].…”

“…The wideranging applications show that the fundamental investigations of the ICP is still an ambitious task. Especially the fact that the ICP can operate in two modes with significantly different electrical and plasma properties [30] requires more knowledge about the behavior during the mode transition.…”

“…With increasing RF power the discharge transits at a critical power value (coil voltage/current) into the inductive (H-) mode characterized by significantly higher plasma density, emission intensity, reduced mean electron energy and electric potentials. That means the electron heating mechanism changes from a dominant capacitive to a dominant inductive coupling [26,27,[30][31][32]. The mode transition starts when in the electron energy balance equation the power absorption of electrons can not be equalized by their power loss processes [33].…”

E-H heating mode transition in inductive discharges with different antenna sizes

“…[10][11][12][13][21][22][23][24][25][26][27][28][29][30] Theoretical studies have been conducted, as follows. Kortshagen et al 31 calculated the critical antenna current to achieve a stable H mode.…”

Excitation Patterns and Heating Mechanisms During E-H-Mode Transition in Inductively Coupled RF Oxygen Discharges

“…The apparently prolonged duration of the pattern I indicates a transition phase between the E-and H-mode in the oxygen ICRF discharge. The development of the complete H-mode with the two characteristic excitation patterns IV in the first and second halves of the RF cycle is combined with a significant voltage drop from 7.7 to 6.5 kV and there with a change in the discharge impedance [6]. Summarizing, the investigation of the excitation rates enables the distinction of different operation modes of an ICRF discharge.…”