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DS: Fachverband Dünne Schichten
DS 26: Oxides
DS 26.9: Talk
Thursday, March 29, 2007, 17:00–17:15, H34
Structure Formation and Phase Composition of Zirconia Films grown by High Power Pulsed Magnetron Sputtering (HPPMS) — •Christian Klever, Kostas Sarakinos, and Matthias Wuttig — I. Institute of Physics (1A), RWTH Aachen University, 52056 Aachen, Germany
We have employed the novel HPPMS deposition technique for the deposition of ZrO2 films. ZrO2 is a polymorphic material, which in thin film form exhibits exceptional mechanical and optical properties and is therefore widely used as a functional coating. In HPPMS unipolar pulses of high–peak power/current and low duty cycle are applied to the target. As a result of the unique properties of the deposition process, several film properties can be improved.
In this study, pulses with pulse off–times toff ranging from 450 to 2450 µs (pulse on–time ton kept constant at 50 µs) are applied to a Zr target (cathode). The films are deposited in a mixed Ar–O2 ambient on unheated silicon substrates at a constant working pressure (1.5 Pa). Ion saturation current measurements are performed using a flat electrostatic probe. They manifest an increase of the ion flux to the growing film when toff is increased. The changes of the duty cycle settings are accompanied by changes in the film structure. It is shown that monoclinic films are obtained when toff is higher than 950 µs, while films with a mixed monoclinic/cubic phase composition are deposited for lower toff. Also, the effects of the sputtering pressure and substrate temperature on the structure of films grown for toff below 1450 µs are investigated.