Radio-frequency discharges in oxygen: I. Particle-based modelling

Abstract

In this series of three papers we present results from a combined experimental and theoretical, particle-based study to quantitatively describe capacitively coupled radio-frequency discharges in oxygen. The particle-in-cell Monte Carlo model on which the theoretical description is based is described in this paper. It treats space charge fields and transport processes on an equal footing with the most important plasma–chemical reactions. For given external voltage and pressure, the model determines the electric potential within the discharge and the distribution functions for electrons, negatively charged atomic oxygen and positively charged molecular oxygen. Previously used scattering and reaction cross section data are critically assessed and in some cases modified. To validate our model, we compare the densities in the bulk of the discharge with experimental data and find good agreement, indicating that essential aspects of an oxygen discharge are captured.

Control of plasma properties in capacitively coupled oxygen discharges via the electrical asymmetry effect

“…The former is beyond the scope of a one-dimensional model and we thus assume a constant density of O 2 (a 1 g ) in the whole chamber of 10% of O 2 density (corresponding to the data of Gudmundsson et al [46] at the chamber center) as Bronold et al did in [48]. For the collisions, which only have rate constant κ available, we adopt Nanbu's method [62] based on Direct Simulation Monte Carlo.…”

“…This has been our motivation of conducting a combined experimental, numerical and analytical investigation of CCRF discharges in pure oxygen. Oxygen discharges, being one of the simplest electronegative plasma system, provide an interesting scenario for theoretical modeling (see for example [41][42][43][44][45][46][47][48][49][50]52] and references therein) and experimental diagnostics [49,50,[52][53][54][55][56][57] of electronegative plasmas. In contrast to the previous work of the EAE in oxygen discharges with only numerical simulation [36], our complementary approach here certainly promises a more comprehensive description of the discharge properties.…”

Behavior of a porous particle in a radiofrequency plasma under pulsed argon ion beam bombardment

“…A one-dimensional (1D) model of the RF discharge is used, which is expected to provide rather realistic plasma parameters of the RF plasma sheath as long as the dust particle is placed close to the central axial discharge region and still is computationally treatable on a single CPU on a standard PC. By using the experimentally known time-dependent bias voltages, the model represents quite well the dynamics of the potential, densities and velocities of all species [20,21]. The simulation yields discharge parameters such as temperature, plasma potential, velocity and density of plasma species (Ar + , e − ) at various positions in the discharge including the dust particle location.…”

Excitation Mechanisms and Sheath Dynamics in Capacitively Coupled Radio‐Frequency Oxygen Plasmas

“…Newly developed models, which use the particle-in-cell (PIC) method combined with Monte-Carlo collisions (MCC) allow an accurate resolution of charged particles distribution functions and their fluxes to the electrode [11][12][13][14][15]. To interpret experimental results like the excitation patterns in capacitively coupled plasmas (CCPs) accurately and to simulate such plasmas adequately with PIC-MCC simulations, a close interaction of experiment and modeling is necessary which can lead to detailed microscopic and macroscopic understanding of the processes in such plasmas [11,12,16].…”