Berlin 2005 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 19: Schichtabscheidung

DS 19.4: Vortrag

Dienstag, 8. März 2005, 15:00–15:15, TU HS107

Investigation of a pulsed magnetron discharge by time-resolved diagnostics — •Thoralf Dunger, Thomas Welzel, Stephan Welzel und Frank Richter — TU Chemnitz, Institut für Physik, 09107 Chemnitz, Germany

An asymmetric bipolar pulsed magnetron sputtering process with a Mg target in Ar / O₂ was investigated by time-resolved Langmuir double probe measurements and optical emission spectroscopy (TrOES).

In the "on phase", the charge carrier density n(t) shows two initial maxima followed by a transition into a stationary state. Both height and temporal position of the maxima were found to be influenced by the pulse parameters. In the "off phase", the charge carrier density decreases exponentially with typical time constants of 0.5 µ s. The second maximum is mainly influenced by the reverse time which is related to the residual charge carrier density at the end of the "off phase".

With TrOES, the most intense Ar and Mg emission lines were studied. Their temporal behaviour is comparable to that of the charge carrier density. However, the maxima appear usually somewhat after those of the charge carrier density and the decay constants are larger. These differences depend on the particular emission line due to differences in the excitation mechanisms. It was found, that the Ar 750.4 nm line is best suited for a comparison to the charge carrier density.