Monte-Carlo simulation of electron properties in rf parallel plate capacitively coupled discharges

TLDR

Electron properties in a parallel‑plate capacitively coupled RF discharge are investigated using Monte‑Carlo simulation. The study computes time‑averaged, spatially dependent electron distributions by integrating electron trajectories under an oscillating RF electric field, while self‑consistently solving for the DC sheath potential. When the secondary emission coefficient is high, the electron distribution becomes spatially differentiated with an e‑beam near the electrodes and near‑equilibrium in the bulk, and the DC sheath potential scales with the ratio of electron mean free path to electrode spacing.

Abstract

Electron properties in a parallel plate capacitively coupled rf discharge are studied with results from a Monte‐Carlo simulation. Time averaged, spatially dependent electron distributions are computed by integrating, in time, electron trajectories as a function of position while oscillating the applied electric field at rf frequencies. The dc component of the sheath potential is solved for in a self‐consistent manner during the simulation. For conditions where the secondary emission coefficient for electrons from the electrodes is large, the electron distribution is spatially differentiated, being dominated by an e‐beam component near the electrodes while being nearly in equilibrium with the applied electric field in the body of the plasma. The dc component of the sheath potential is found to be a function of the ratio λ/d, where λ is the electron mean free path and d is the electrode spacing.