Plasma Edge Layers

Everywhere where a plasma has contact with a surface, an edge layer is created - especially at every workpiece or substrate which is supposed to be proccessed with the help of plasma. The edge layer is an electron-depleted zone that separates the surface from the quasi-neutral bulk plasma. Ions from the bulk are accelerated through the edge layer tension to the surface, whhich they hit with high energy. Meanwhile, a majority of electrons are reflected by the edge layer because they are negatively charged. Among other things, the flow of ions to the surface enables the nanostructuring of semiconductor devices for the production of modern ultra-miniaturised integrated circuits and computer chips. 

The edge layer is the region that is the the most important for the surface process which is why it is crucial to describe it predicatively and mathematically. Generally, this description need Maxwell equasions and hydrodynamic equasions, which describe the ionic component of the plasma as a fluid. By using the physical conditions, these equasions can be simplified to set up a tractable boundary layer theory. 

The Chair of Theoretical Electrical Engineering mainly deals with setting up analytical boundary layer models, both for static and radio frequency driven edge layers.