Transparent conductive oxides (TCOs) are widely used as transparent electrodes for various applications, such as flat-panel displays and IR reflecting glasses. Ta-doped SnO2 (TTO) films have recently attracted much attention as TCO material due to high thermal stability. As for the sputter deposition of this material, rf magnetron sputtering is adopted because the target is not conductive. In this study, we used dc magnetron sputtering to deposit the TTO film by using the sintered TTO target, where a small amount of ZnO is added into the target to obtain the high packing density and good conductivity. Moreover, in order to decrease the effect of bombardment of highly-energetic particles on the film properties during the deposition, the off-axis dc magnetron sputtering is utilized.
TTO films were deposited on synthesized glass substrates heated at 400 °C using the high-dense target (Ta: 6.8 at.%, AGC Ceramics). The distance between substrate and target was 110 nm. The total gas pressure during deposition was maintained at 0.5 Pa. The sputtering gas was Ar, and the reactive gas was O2. The sputtering power was kept at 50 W. The film thickness was 400 nm.
XRD patterns showed that TTO films had a high crystallinity at the off-axis positions, which is due to the almost bombardment-free of high-energetic particles during the deposition. The lowest resistivity of the TTO films of 7.9 × 10−3 Ω cm was also obtained at the off-axis position, which may be attributed to the improvement of the crystallinity.
 J. Jia, et al., Thin Solid Films 559 (2014): 69-77