Influence of neodymium content on structural properties and electrical characteristics of high-k NdTiO₃ gate dielectrics

A high- k NdTiO3 gate dielectric was formed in films using Ti added to Nd2 O3 film prepared under various Nd metal thicknesses through radio frequency (rf) sputtering and annealed at 700°C. The structural and compositional features of these films were studied through X-ray diffraction and X-ray photoelectron spectroscopy. We found that the NdTiO3 gate dielectric using a 3 nm Nd metal film exhibited a reduced equivalent oxide thickness, interfacial density of states, and hysteresis voltage; it also showed negligible charge trapping under high electric voltage stress. We attribute this behavior to the high neodymium content in the NdTiO3 film suppressing the formation of interfacial SiO2 and silicate layer at the NdTiO3 /Si interface.