AVS 53rd International Symposium
    Thin Film Tuesday Sessions
       Session TF-TuP

Paper TF-TuP1
Effect of Particle Transport Process on Mode Transition and Film Composition during Reactive Sputtering of Metal Oxides

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Thin Film Poster Session
Presenter: T. Nakano, Seikei University, Japan
Authors: T. Nakano, Seikei University, Japan
Y. Iimura, Seikei University, Japan
S. Baba, Seikei University, Japan
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Target mode transition and film composition during the DC reactive sputter deposition process has been studied for various metal oxides, especially focused on the effect of the particle transport process of sputtered atoms. Si, Ti and Nb targets were sputtered in a gas mixture of argon and oxygen. These targets were chosen to elucidate the effect of the atomic mass on the reactive sputtering through the particle transport process of sputtered atoms. At a fixed argon gas flow rate of 20 sccm, evacuation valve was throttled to achieve a gas pressure between 0.5~2 Pa. At this fixed pumping speed, oxygen flow rate was modified and the transition between the metal and oxide modes was monitored by the cathode voltage. Deposition rate was measured in-situ by a quartz crystal monitor, and the composition of deposited films was measured by X-ray photoelectron spectroscopy. In case of Si sputtering, the mode transition occurred at distinctly lower oxygen flow rate as the pumping speed was decreased and argon gas pressure increased. In addition, at each pumping condition, the oxygen content of deposited film was saturated at lower flow rate than that of the mode transition, which means that the film was totally oxidized while the target was in the metal mode. These results cannot be explained by the Berg's model@footnote 1@ in which the metal to oxide mode transition accompanies the oxidization saturation of deposited metal atoms on the chamber wall, and the reduction of the oxygen gettering. On the contrary, these effects were much more subtle in heavy Nb case. It can be ascribed to the transport behavior of Si sputtered atoms which are lighter than argon atoms and are easily backscattered by them. At higher gas pressures, Si sputtered atoms tend to redeposit on (or around) the target surface, which results in the reduction of both the total gettering speed and its uniformity. @FootnoteText@ @footnote 1@ S. Berg and T. Nyberg: Thin Solid Films vol. 476 (2005) 215.