AVS 49th International Symposium
    Plasma Science Friday Sessions
       Session PS-FrM

Paper PS-FrM6
The Interaction Dynamics of Ar/H Plasmas with Silicon Surfaces

Friday, November 8, 2002, 10:00 am, Room C-103

Session: Plasma Surface Interactions II
Presenter: M.A. Gleeson, Leiden University, The Netherlands
Authors: J. Villette, Leiden University, The Netherlands
F. Gou, Leiden University, The Netherlands
M.A. Gleeson, Leiden University, The Netherlands
A.W. Kleyn, Leiden University, The Netherlands
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Despite its technological importance the basic reaction dynamics of plasma deposition and etching processes are not known, even though in this case the process takes place almost under vacuum and should be easily accessible to studies at the molecular level. We have developed a new machine for such studies. Samples are placed in the centre of a 70 cm diameter reaction chamber, which can be evacuated up to ultra high vacuum. A cascaded arc plasma source produces an atmospheric plasma, which is collimated and differentially pumped. With a quadrupole mass spectrometer (QMS) we can monitor the particles emitted. An ion beam is produced in an independent source and can be scattered from the crystal that is being modified by the plasma. A time and position sensitive detector (PSD) records the scattered ions and neutrals individually. From their energy and scattering pattern we reconstruct the actual state of the surface. In order to prepare and characterize samples we can remove them from the reaction chamber into the preparation chamber under vacuum. Scattering of protons from clean and hydrogen covered silicon has been studied extensively by Souda et al.@footnote 1@ The protons reflection is very sensitive to the state of the surface. In our machine we apply this to hydrogen treatment of Si(110). We note that the reflected yield goes up dramatically when switching on the hydrogen discharge. Switching to an Ar discharge we observe the disappearance of the strong hydrogen signal, indicating that even hyperthermal Ar from a cascaded arc recombining plasma is capable of removing hydrogen from silicon. @FootnoteText@@footnote 1@ R. Souda, E. Asari, T. Suzuki, and K. Yamamoto, Surf. Sci. 431, 26 (1999).