Different pulse techniques for stationary reactive sputtering with double ring magnetron

Double Ring Magnetron (DRM) sources are suitable for stationary uniform coa ting of large substrates with metals, alloys and insulating layers. DRM sou rces are characterized by two concentric discharges on electrically insulat ed targets. Therefore, different pulse techniques in the frequency range be tween 10 and 100 kHz can be applied: (i) a voltage with alternating polarit y between the inner and outer target (bipolar mode); (ii) a pulsed d.c. vol tage for both of the targets (unipolar mode). Process parameters like energetic ion flux towards the substrate and therma l load as well as layer properties like mechanical stress and hardness are influenced by the pulse technique and the pulse parameters. Pulsed reactive sputtering allows a high rate deposition even of insulating compounds. Furthermore, unique materials such as compounds with multiple g as constituents (e.g. ternary compounds) or layers with changing compositio n (gradient layers) can be deposited. It will be shown that by adjusting th e reactive gas flow ratio of oxygen and nitrogen, oxynitride layers with a defined composition and refractive index can be deposited. Gradient layers have been produced by changing the reactive gas flow ratio during depositio n, including the appropriate adaptations of the reactive working point. (C) 1999 Published by Elsevier Science S.A. All rights reserved.