Band alignments of O3-based and H2O-based amorphous LaAlO3 films on silicon by atomic layer deposition

Abstract

Amorphous LaAlO3 films were grown on p-type Si substrate by atomic layer deposition using O3 and H2O as the oxygen source, respectively. Band alignments of LaAlO3 films were analyzed by X-ray photoelectron spectroscopy measurements using the photoemission-based method. Extra hydroxyl groups and C and N-related impurities were detected in the H2O-based LaAlO3 film. As a result, the O3-based LaAlO3 dielectric gains higher band gap and band offsets than those of the H2O-based dielectric. Consequently, for the O3-based film, the leakage current of more than one order of magnitude less than that of H2O-based LaAlO3 film was obtained. All the results indicate that O3 is a more appropriate oxidant for the deposition of LaAlO3 dielectric.