Plasmakontakt

Plasmakontakt is the interface where a plasma comes into contact with a solid surface or boundary. At this boundary, exchange processes involving charge, energy, and particles occur, and the exact behavior depends on plasma parameters (temperature, density, gas composition) as well as surface properties (material, roughness, coatings).

When a surface is exposed to a plasma, a sheath forms in front of the boundary. Positive ions are accelerated toward the surface and may sputter material, implant ions, or drive chemical reactions. Reactive species can adsorb and react, leading to etching, deposition, or surface modification. The interaction can alter surface chemistry, morphology, and work function, and excessive energy can cause heating or arcing.

Plasmakontakt is central to many technologies. In industry, it underpins plasma etching and plasma-enhanced deposition used in semiconductor fabrication, as well as surface cleaning, activation, and coating processes. Plasma medicine and surface treatment at atmospheric pressure extend these ideas to medical and industrial applications.

Studying plasmakontakt relies on plasma diagnostics such as Langmuir probes and optical emission spectroscopy, combined with post-exposure surface analysis (X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy) to assess changes in composition, roughness, and chemistry.

Controlled plasmakontakt requires carefully designed reactor geometry, power supply, gas feed, and safety measures, because of high voltages, reactive species, and potential contamination or unintended damage to sensitive surfaces.