Spatiotemporal electron dynamics in radio-frequency glow discharges: fluid versus dynamic Monte Carlo simulations

Abstract

A particle-in cellldynamic Monte Carto simulation technique was developed to study the spatiotemporal electron dynamics in radio-frequency glow discharges. The electric field profile in a parallel plate one-dimensional geometly was obtained from a self-consistent fluid simulation. Using this profile, the particlein-celVdynamic Monte Carto simulation yielded the spatiotemporal electron velocity distribution function between the electrodes. A strongly electronegative chlorine discharge and an electropositive argon discharge were considered. At a pressure of 100 mTorr, the distribution function was non-Maxwellian except at the midgap of the chlorine discharge. The tail of the distribution was strongly modulated inside the sheath. Electron 'pile-ups' near the walls, charge double layers and negative plasma potential during part of the cycle were observed in the electronegative discharge at 13.56 MHz. lime-average results from the particle-in-cell/dynamic Monte Carlo simulation matched the fluid simulation favourably, even at a local Knudsen number Kn % 1, with differences confined mainly to the volume around the plasmahheath interface.

Double layer onset inside the near-electrode sheath of a RF capacitive discharge in oxygen

“…In a number of cases this section of EEPF contains a linear section; therefore we can evaluate the electron temperature from its tilt with respect to the abscissa axis (assuming the low energy electrons to possess a Maxwell distribution). The electron temperature thus determined turns up to be remarkably higher than one at the centre of the discharge gap in agreement with the results of papers [34][35][36][37]. Regarding the observation of two peaks in the electron temperature profile we can say that: (1) at voltages above 55 V the registration of this pattern might require increased spatial resolution, and (2) with the voltage increasing there is a clear tendency of smoothing.…”

“…We observed no additional glowing regions inside the sheath in argon. The experimental data we obtained for T e are in good agreement with the calculations from [37]. At the same time we observed an additional brightly shining layer inside the nearelectrode sheath of the RF discharge in electronegative gases SF 6 and CF 4 .…”

“…This is caused by the increased ionisation rate in the region of existence of the double layer which 2-3 times exceeds one at the centre of the discharge gap in the quasi-neutral plasma. The authors of papers [25][26][27][28][29]36,37,39,40,42] obtained similar U, E and N e profiles for the anode phase of the nearelectrode sheath of the RF discharge in electronegative gases. Perhaps it is the onset of the double layer at the anode phase that leads to the local increase of the electron temperature inside the near-electrode sheath we discovered in the experiment.…”

Modes of rf capacitive discharge in low-pressure sulfur hexafluoride

“…Therefore the transition to the dissociative regime could hardly be explained as a 'local breakdown' within the double layer region because in α-mode the double layer is already 'broken down'. The authors of papers [8,9,[28][29][30][31][32][33][34][35][36] obtained similar U , E and N e profiles for the anode phase of the near-electrode sheath of the rf discharge in electronegative gases.…”

Predicting the amount of carbon in carbon nanotubes grown by CH4 rf plasmas

“…The detail of the numerical scheme is based on earlier works. [18][19][20][21] The number densities n j of electrons, neutrals and ions ͑subscript j represents species͒ are calculated spatiotemporally by the following continuity equations:…”