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P: Fachverband Plasmaphysik

P 8: Niedertemperaturplasmen

P 8.12: Talk

Tuesday, March 31, 2009, 16:35–16:50, INP-Staffelgeschoß

Design of arbitrary bias waveforms for tailored ion bombardment during plasma processing — •Tim Baloniak, Rüdiger Reuter, and Achim von Keudell — AG Reaktive Plasmen, Ruhr-Universität Bochum, Deutschland

Substrate biasing is an established technique to control and adjust material properties during thin film deposition from a plasma. The energy distribution function of the ions impinging onto the substrate (IEDF) is manipulated by the external bias voltage. Optimal ion bombardment can significantly improve film properties like hardness, adhesion, crystallinity, or wear resistance. In our contribution, we report about the quantitative measurement of ion energy distribution functions on arbitrarily biased substrates. The measurements are performed in a magnetically enhanced, capacitively coupled argon discharge, which is heated by 13.56 and/or 71 MHz. An aluminum target is mounted on the powered electrode. The substrates are placed on an arbitrarily biased electrode driven by RF waveforms at 1 MHz. A miniaturized, floating retarding field analyzer allows for IEDF measurements on the biased substrate holder. The energy distributions are found to be good replica of the bias waveforms applied to the substrate, eventually skewed by collisions at higher pressures. Our findings allow to design tailored waveforms for optimal ion bombardment and thus, optimal film properties.