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H. Störi, J. Laimer, M. Kemetmüller, W. Schoßböck, D. Heim, C. Forsich, I. Gebeshuber, M. Proschek:
"Deposition of Si-DLC coatings at moderate temperatures by bipolar pulsed dc PACVD";
Poster: 13th International Conference on Plasma Surface Engineering (PSE 2012), Garmisch-Partenkirchen/Germany; 12.09.2012.

A common technique to produce silicon doped diamond-like carbon coatings (Si-DLC also referred as a-C:H:Si) is plasma-assisted chemical vapour deposition (PACVD) by utilizing radio-frequency (RF) discharges. Recently, it was demonstrated that high quality Si-DLC can be also deposited in pulsed direct-current (dc) discharges in spite of the insulating nature of such a coating. In order to reduce the probability of arcing often bipolar pulsed dc discharges are used instead of unipolar discharges. Usually, the deposition takes place at temperatures well above 400 °C.
In the present study a systematic investigation of Si-DLC deposition using bipolar pulsed dc PACVD was performed in the temperature region between 280 and 340 °C. The process gas consisted of argon, hydrogen, methane and HMDSO.
The discharge was characterized by current-voltage measuremensts using probes and a digital oscilloscope.
Growth rates obtained were in the order of 1 μm/h. The coatings were analysed by GDOES for chemical composition. The microhardness of the Si-DLC coatings measured with a Fischerscope tester reached under certain conditions values above HV 2000. Scratch tests revealed critical loads in the order of 15 N on hard chromium coated steel substrates.