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P: Fachverband Plasmaphysik

P 13: Atmospheric Pressure Plasmas II

P 13.1: Hauptvortrag

Mittwoch, 18. März 2026, 16:15–16:45, KH 01.020

Thin film deposition with dielectric-barrier discharges at atmospheric pressure: open questions and some answers — •Lars Broecker and Claus-Peter Klages — Institute for Surface Technology (IOT), Technische Universität Braunschweig, 38108 Braunschweig, Germany

Plasma-enhanced chemical vapour deposition (PECVD) with dielectric-barrier discharges (DBDs) at atmospheric pressure is still only partially understood, which makes choosing the most suitable discharge configuration and plasma parameters quite difficult. In particular, the relevance of possible film-forming species, e.g. radicals, charged particles or the monomer itself, and their influence on the mechanical properties and film chemistry is often speculated upon but not fully understood. The determination of characteristic times involved in the deposition process, namely the gas residence time, the times for the transport of neutral particles and ions to the surface by diffusion and drift, respectively, and the time scales of ionic or radical gas phase reactions, can provide important information about the significance of the species for the film deposition process. Interestingly, cations formed from neutral species by electron impact or chemo-ionization are often neglected, even though they drift to the substrate within a few mikroseconds. Recent experiments show that film deposition from ions dominates when the gas residence time is much shorter than the diffusion time of neutral particles. For certain monomers, cationic surface reactions appear to play a role, similar to initiated chemical vapour deposition (iCVD) processes.

Keywords: Dielectric-barrier discharge; PECVD; Plasma polymerisation; Penning ionization; Surface chemistry