18th, Laser Aided Plasma Diagnostics

Diagnostic studies of technological plasmas using quantum cascade lasers

Sep 26, 2017, 11:10 AM

25m

INVITED TALK Low-temperature plasmas Topical

Speaker

Dr Norbert Lang (INP Greifswald)

Description

Molecular plasmas are increasingly used not only for basic research but also technologically for materials and surface processing, environmental challenges, and plasma medicine. Nowadays, they play a key role in branches of industry like semiconductor, automotive, mechanical engineering, light sources, and biomedical technology to name a few. Typical applications are thin film deposition, etching and structuring of semiconductor devices, and surface treatment, such as activation, passivation and cleaning as well as materials and waste treatment. The intense use of plasma technological processes calls for appropriate plasma diagnostic techniques for monitoring, controlling and optimization purposes in industrial environments. In particular, for reasons of efficiency of production processes, in situ diagnostic techniques with online capabilities are favorable. \\ Mid-infrared absorption spectroscopy between 3 and 20 µm using quantum cascade lasers (QCLs) has progressed considerably as a powerful diagnostic technique for in situ studies of the fundamental physics and chemistry of molecular plasmas [1]. QCL based absorption spectroscopy (QCLAS) provides a means of determining the absolute ground state concentration of stable and transient molecular species, which is of particular importance for the investigation of reaction kinetics. Since QCLs emit near room temperature, i.e., without the need of cryogenic cooling, very compact and robust spectroscopic instruments can be designed. This has stimulated the adaptation of infrared spectroscopic techniques to industrial requirements [2-10]. \\ The aim of the present contribution is to review recent achievements using QCLAS for plasma diagnostics and to emphasize the potential of QCLAS for plasma technological applications in industry.\\ \\ [1] J. Röpcke, P. B. Davies, S. Hamann, M. Hannemann, N. Lang, J. H. van Helden: Photonics 3 (2016), 45. \\ [2] G. D. Stancu, N. Lang, J. Röpcke, M. Reinicke, A. Steinbach, S. Wege: Chem. Vap. Deposition 13 (2007), 351. \\ [3] N. Lang, J. Röpcke, A. Steinbach, S. Wege: IEEE Trans. Plasma Sci. 37 (2009), 2335. \\ [4] N. Lang, J. Röpcke, A. Steinbach, S. Wege: Eur. Phys. J. Appl. Phys. 49 (2010), 13110. \\ [5] F. Hempel, N. Lang, H. Zimmermann, S. Strämke, J. Röpcke: Meas. Sci. -Technol. 21 (2010), 085703. \\ [6] N. Lang, F. Hempel, S. Strämke, J. Röpcke: Jpn. J. Appl. Phys. 50 (2011), 08JB04. \\ [7] S. Zimmermann, N. Ahner, F. Blaschta, M. Schaller, H. Zimmermann, H. Rülke, N. Lang, J. Röpcke, S. E. Schulz, T. Gessner: Microelectron. Eng. 88 (2011), 671. \\ [8] M. Hübner, N. Lang, S. Zimmermann, S. E. Schulz, W. Buchholtz, J. Röpcke, J. H. van\\ Helden: Appl. Phys. Lett. 106 (2015), 031102. \\ [9] N. Lang, S. Zimmermann, H. Zimmermann, U. Macherius, B. Uhlig, M. Schaller, S. E. Schulz, J. Röpcke: Appl. Phys. B 119 (2015), 219. \\ [10] N. Lang, U. Macherius, S. Glitsch, H. Zimmermann, J. Röpcke, J. H. van Helden: Contrib. Plasma Phys. 55 (2015), 758.

Presentation materials

summary

LAPD-2017_talk_NLang.pdf