TY - JOUR
TI - Nonlocal dynamics of secondary electrons in capacitively coupled radio frequency discharges
AU - Nösges, K
AU - Klich, M
AU - Derzsi, A
AU - Horváth, B
AU - Schulze, J
AU - Brinkmann, R P
AU - Mussenbrock, T
AU - Wilczek, S
T2 - Plasma Sources Science and Technology
AB - In capacitively coupled radio frequency discharges, the interaction of the plasma and the surface boundaries is linked to a variety of highly relevant phenomena for technological processes. One possible plasma-surface interaction is the generation of secondary electrons (SEs), which significantly influence the discharge when accelerated in the sheath electric field. However, SEs, in particular electron-induced SEs (δ-electrons), are frequently neglected in theory and simulations. Due to the relatively high threshold energy for the effective generation of δ-electrons at surfaces, their dynamics are closely connected and entangled with the dynamics of the ion-induced SEs (γ-electrons). Thus, a fundamental understanding of the electron dynamics has to be achieved on a nanosecond timescale, and the effects of the different electron groups have to be segregated. This work utilizes 1d3v particle-in-cell/Monte Carlo collisions simulations of a symmetric discharge in the low-pressure regime (p = 1 Pa) with the inclusion of realistic electron-surface interactions for silicon dioxide. A diagnostic framework is introduced that segregates the electrons into three groups (‘bulk-electrons’, ‘γ-electrons’, and ‘δ-electrons’) in order to analyze and discuss their dynamics. A variation of the electrode gap size Lgap is then presented as a control tool to alter the dynamics of the discharge significantly. It is demonstrated that this control results in two different regimes of low and high plasma density, respectively. The fundamental electron dynamics of both regimes are explained, which requires a complete analysis starting at global parameters (e.g. densities) down to single electron trajectories.
DA - 2023/08/01/
PY - 2023
DO - 10.1088/1361-6595/ace848
DP - DOI.org (Crossref)
VL - 32
IS - 8
SP - 085008
J2 - Plasma Sources Sci. Technol.
LA - en
SN - 0963-0252, 1361-6595
UR - https://iopscience.iop.org/article/10.1088/1361-6595/ace848
Y2 - 2023/08/16/17:34:18
ER -