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DS: Dünne Schichten

DS 24: Poster presentation

DS 24.59: Poster

Dienstag, 28. März 2006, 15:00–17:30, P2

Plasma stabilization and increase of the deposition rate during reactive sputtering of metal oxides — •Daniel Severin¹, Oliver Kappertz², Tomas Nyberg², Sören Berg², Andreas Pflug³, Michael Siemers³, and Matthias Wuttig¹ — ¹I. Institute of Physics (1A), Aachen University, Germany — ²Solid State Electronics Division, Uppsala University, Sweden — ³Fraunhofer IST, Braunschweig, Germany

Reactive sputtering is an attractive technique for the deposition of metal oxides. One of its main drawbacks, however, is the hysteresis and process instability encountered in the transition from the metallic to the compound mode, where films can be deposited most rapidly with desirable properties. Here we present a method to stabilize the undesirable abrupt transition between metallic and compound mode. The addition of nitrogen in the plasma gas leads to supplanting of oxygen by nitrogen on the target’s surface and coverage with the corresponding nitride. Due to the lower reactivity of the nitride compared to the oxide and a smaller effective target area the hysteresis vanishes. In addition a higher deposition rate is achieved since the sputtering rates of the nitrides are generally higher than those of the corresponding oxides. The observed behaviour can be qualitatively explained and theoretically predicted using an extention of Berg’s model to two different reactive gases. Although the nitrogen addition leads to pronounced changes of the plasma, the incorporation of nitrogen atoms in the growing film is very small as predicted by theory.