Working Fields

Our main interest is plasma research.

One part is basic research:
What happens in a highly reactive plasma which is excited by various methods which produce so-called low density plasmas (capacitively driven, as in conventional sputter systems or parallelplate reactors), or, by contrast, high density plasmas (inductively driven or driven by resonant techniques like ECR, ECWR, or helicons)? In this area, the main issue is first measuring of plasma parameters like plasma density, temperature of electrons and gaseous components, DC conductivity, electrical parameters like the complex impedance.
Second, to model these plasmas: to get an idea of how the power of the electromagnetic field is absorbed by and dissipated into the plasma.

The other great part is interaction of the plasma with surfaces for anisotropic etching.
Here, we are mainly interested in creating structures which are rectangularly carved into the substrate with a lateral pattern fidelity as high as possible. During my time at Siemens, we managed to etch 100 microns in depth into GaAs with an undercut of less than 2 microns (Flying Carpet in the middle of the picture bar atop the Start Page). This is a so-called aspect ratio of 50. But also RIE of metals is still in the focus. In 2002, we could etch platinum free of residuals, and in 2017, we succeeded in removing gold films by a physically-induced chemical process. Both constitute the Bell contact which is still in use in III/V processing technology.

Since etching means inevitable damage, a third area of research is damage of the remnant surface and topmost volume. This has been accomplished by applying several diagnostic techniques to surfaces and three dimensional structures, mostly during my time at Siemens where I had been member of the Munich based Research Laboratory, Photonics division. Consequently, my etching work focused on III/V semiconductors, but also SiC substrates (blue glowing LEDs) and Pt films (part of the Bell contact) were matter of interest.
Damage will be an area of topical research again, since my collegue Hans-Christian Alt and me have founded a center of competency which is called Center of Nanostructuring Technology.

From 2005, chemical vapor deposition of poly-p-xylylen has come into the focus of our research. Starting with basic investigations concerning the exact determination of vapor pressure and plasma-relevant parameters (plasma density, electron temperature), we intensively work on the development of antibacterial catheters for urological applications.

Plasma Diagnostics

III/V Semiconductors





Chemical Vapor Deposition