Speaker
Jean-Pierre Hubertus van Helden
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/I1.302.pdf
Plasma-surface interaction studies:
Development and application of advanced laser-based diagnostics
N. Lang1, A. D. F. Puth1, S.-J. Klose1, G. Kowzan2, S. Hamann1, J. Röpcke1, P. Maslowski2,
J. H. van Helden1
1
Leibniz Institute for Plasma Science and Technology (INP Greifswald), Felix-Hausdorff-Str.
2, 17489 Greifswald, Germany
2
Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus
University in Toruń, ul. Grudziądzka 5, 87-100 Toruń, Poland
Understanding how plasmas interact with solid and liquid surfaces is of central importance in
many fields such as microelectronics and biophysics, and industrially in environmental and
biomedical technologies. Improving processes, such as the growth and etching of materials and
surface modification, requires a comprehensive understanding of the kinetics of the transient
intermediates involved at the plasma-substrate interface. The experimental approaches
currently available provide an incomplete picture of plasma-surface interactions due to
relatively low sensitivity, low time resolution, and restricted multi-species capability.
We use a state of the art mid-infrared frequency comb (FC) to provide novel spectroscopic data
on plasma-surface problems. Broadband direct frequency comb spectroscopy (DFCS), based
on FCs as the light source, can detect many transient species simultaneously yielding
comprehensive data on their kinetics in the plasma and their interactions with a surface down
to the microsecond timescale. The measurement of the plasma environment close to a surface
with the high sensitivity and time resolution of DFCS will provide new fundamental insights
into the physics and chemistry of the interfacial region. Moreover, the sensitivity of DFCS can
be further greatly enhanced by combining it with a high finesse optical cavity, suggesting
unprecedented opportunities for ultra-high sensitivity plasma analysis over large spectral
bandwidths. We demonstrate the capabilities of the advanced laser-based diagnostics by
showing the latest results on the spectroscopic investigations of plasma nitrocarburizing
processes with mid-infrared DFCS. We will discuss the workings of DFCS and the influence
of process parameters, such as pressure, screen plasma power, and gas mixture, on the
concentrations of the key process species such as NH3, C2H2, C2H6, HCN, and CH4 molecules.
