High rate and low temperature deposition of TiO2 films by sputtering

Abstract

In reactive sputtering of titanium target in the oxide mode, oxygen atoms are selectively sputtered from the target surface, which leads to a significant reduction of deposition rate of TiO2 films. Utilizing this phenomenon, we developed a sputtering type oxygen radical source. Combining this oxygen radical source with a titanium sputtering source which is operated in metal mode, we showed that a high rate deposition of TiO2 films above 40 nm/min was achieved. In addition, it was confirmed that the crystal structure of the film (anatase and/or rutile) was easily controlled by the control of the amount of oxygen radicals and titanium atoms incident on the substrate surface. Low temperature deposition of crystallized TiO2 films was also attempted by using this sputter-deposition method. As a result, it was found that deposition of a well crystallized TiO2 films on unheated substrate could be realized by using crystallized TiO2 seed layer and a proper ion bombardment.