Annealing effects on the polarity of stored charge of BaTiO3 films on Si

A high quality BaTiO₃/p-Si interface was achieved at substrate temperature of 500°C by using RF magnetron sputtering. In-situ annealing at the same temperature was carried out to study the charge behavior of BaTiO₃ films on Si substrate. Depending on the annealing oxygen pressure and annealing condition, both polarities of effective oxide charge in the metal-ferroelectric-semiconductor, Au/BaTiO₃/p-Si, structure was observed. It is believed that the density of electronic states, generated at the interface due to the asymmetry of the structure between BaTiO₃ and Si substrate, and the positive oxide charges, depending on the degree of the metal-oxygen reaction for different annealing oxygen pressures and annealing durations, determines the behavior of oxide charge