High-temperature anomalies of dielectric constant in TiO2 thin films

Anatase and rutile TiO2 thin films were prepared by chemical vapor deposition with precursors Ti(OPri)4 and Ti(dpm)2(OPri)2 (dpm = 2,2,6,6-tetramethylheptane-3,5-dione and Pri = isopropyl), respectively. The dielectric properties of TiO2 thin films have been studied in 20–1100 K temperature range in air, in controlled Ar/O2 atmospheres, and in vacuum with silicon-based metal-insulator-semiconductor Au/TiO2/Si capacitors. High-temperature (Tc ∼ 980 K) anomalous behavior of dielectric constant was observed in both anatase and rutile TiO2 thin films.