Electrical properties of anatase TiO₂ films by atomic layer deposition and low annealing temperature

In this paper, the authors studied anatase TiO₂ films, fabricated by using atomic layer deposition and postdeposition annealing (PDA). The as-grown TiO₂ films were of high purity; the carbon and nitrogen contents were within the x-ray photoelectron spectroscopy detection limit of 3-5 at. %. The anatase TiO₂ film fabricated by PDA at 500°C in O₂ had a very high dielectric constant of >30 and was of high quality because it exhibited no hysteresis at its flatband voltage (V _fb) and contained negligible defect charge. The positive V _fb shift of anatase TiO₂ (0.08 V), caused by the bottom interface dipole at a TiO₂/SiO₂ interface, was much smaller than those of Al₂O₃ (0.72 V) and HfO₂ (0.29 V). However, the maximum V_fb change of the anatase TiO ₂ was greater than those of HfO₂ and HfSiO_x because the TiO₂ contained more oxygen than the other materials.