Effects of the Interfacial Layer on Electrical Properties of TiO2-based High-k Dielectric Composite Films

Abstract

Effects of interfacial layer on the electrical properties of TiO2 based dielectric thin films prepared by atomic layer deposition are investigated. It was confirmed from XPS data that the Hf-silicate and La-silicate interfacial layers including SiOx were formed in the interface of the HfO2/TiO2/Al2O3 (HTA) and La2O3/TiO2/Al2O3 (LTA) gate stack structures, respectively. In addition, the dielectric constants and leakage currents of HTA and LTA structures were affected by the formation of Hf-silicate and La-silicate layer in the interface and crystallization of TiO2 thin film, respectively. It was also found that the LTA thin film annealed at 600 °C showed the low equivalent oxide thickness of 0.91 nm and the low leakage current of 4.16×10-6 A/cm2 at 4 MV/cm.