High Rate Sputter-Deposition of TiO2 Films Using Oxide Target

Yoichi HOSHI  Tomoki TAKAHASHI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E87-C   No.2   pp.227-231
Publication Date: 2004/02/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Progress in Oxide Thin Films by Sputtering)
Category: 
Keyword: 
TiO2 film,  magnetron sputtering,  high-rate sputtering,  oxide target,  ion mass analysis,  

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Summary: 
The sputter-deposition process of TiO2 thin films was investigated. When an oxide target is used, high-rate deposition above 57 nm/min can be realized by sputtering under a condition of low oxygen gas content. Under this sputtering condition, a Ti rich surface layer is formed by selective sputtering of oxygen atoms, and a large amount of Ti atoms are sputtered from this layer. The deposition rate, however, decreases steeply as the oxygen gas content increases. This decrease can be explained as follows. When a sufficient amount of oxygen gas is supplied into the chamber during sputtering, the oxygen atoms which are missing from the target surface by selective sputtering are filled up immediately. This leads to a very low deposition rate of the film, because only oxygen atoms are sputtered from the target. Therefore, the suppression of the incidence of oxygen gas to the target surface and a sufficient of oxygen supply to the substrate are necessary to realize the high-rate deposition of stoichiometric TiO2 films. From this point of view, using an oxide target instead of a metal target is useful for realizing a stable high-rate deposition of the film, since the amount of oxygen gas introduced in to the sputtering chamber can be reduced significantly. In addition, it was confirmed that pulse sputtering method is a useful technique for the deposition of TiO2 thin films. Meanwhile, low-voltage sputtering technique was difficult to use for the film deposition because of its low deposition rate.