Tuning the electrical resistivity of pulsed laser deposited TiSiO_(x) thin films from highly insulating to conductive behaviors

摘要

We report on the successful growth of amorphous TiSiO_(x) thin films by means of pulsed-laser ablation of a TiO_(2)/SiO_(2) composite target in a high-vacuum chamber. The room-temperature resistivity of the TiSiO_(x) films is found to decrease by more than 6 orders of magnitude (i.e., from ～2×10~(4) to 10~(-2) Ω cm) when their substrate deposition temperature (T_(d)) is increased from 20 to 600℃. On the other hand, by subjecting these films to a post-deposition annealing at 600℃ in oxygen atmosphere, they become highly insulating with a resistivity level as high as 2×10~(10) Ω cm, regardless of the T_(d) value. The presence of conductive titanium silicide and titanium sub-oxide local phases in the as-deposited TiSiO_(x) films, as revealed by photoelectron spectroscopy analyses, appears to be the cause of the observed tremendous change in the film resistivity. In particular, it is shown that the resistivity of the TiSiO_(x) films is strongly correlated with their oxygen content.