| AVS 54th International Symposium | |
| Advanced Surface Engineering | Wednesday Sessions |
| Session SE-WeM |
| Session: | Photocatalytic Coatings |
| Presenter: | Y. Hoshi, Tokyo Polytechnic University, Japan |
| Authors: | Y. Hoshi, Tokyo Polytechnic University, Japan O. Kamiya, Tokyo Polytechnic University, Japan T. Sakai, Tokyo Polytechnic University, Japan |
| Correspondent: | Click to Email |
Deposition of TiO2 films by reactive sputtering of titanium metal target has been reported by many researchers. However, it is very difficult to realize the high rate deposition of TiO2 films by conventional reactive sputtering, since the surface of the target is covered with titanium oxide layer, which leads to a significant reduction of the sputtering yield of titanium atoms. If we can suppress the formation of titanium oxide layer on the target surface and promote the oxidization of titanium atoms on the film surface during sputtering, high rate deposition of titanium oxide films can be realized by using the reactive sputtering method. In this point of view, we designed a new sputter-deposition system with two sputtering sources. One source, 33mm diameter magnetron sputtering source, is used as the source of titanium atom, and works at the metal mode sputtering condition and supplies the titanium atoms to the substrate. The other source of 100 mm in diameter works as an oxygen radical source and supplies oxygen radicals to the substrate surface to promote the oxidization of the titanium atoms during film deposition. Each sputtering sources are separated from deposition chamber and Ar gas and oxygen gas was introduced through the 33mm sputtering source and 100mm source, respectively. When Ar gas flow rate is fixed at 50 sccm and oxygen gas flow rate was below 8mTorr, the 33mm titanium sputtering source works in metal mode at a discharge current of 1 A. Whereas, the 100 mm oxygen radical source works in an oxide mode at an oxygen gas flow rate below 8 sccm and the sputtering current below 1.5 A. In this deposition method, most of the titanium atoms deposited on the substrate are supplied from the 33 mm sputtering source, and oxygen radicals supplied from 100mm source promote the oxidization of titanium atoms on the substrate. As a result, deposition rate more than 30 nm/min can be easily realized for the deposition of transparent TiO2 film with transmittance above 90%. These results indicate that the reactive sputtering method with two sputtering sources is effective to realize a high rate deposition of TiO2 films.