Surface termination effects on the electrical characteristics of La₂O₃/Al₂O₃ nanolaminates deposited by atomic layer deposition

Effects of initial surface termination on electrical characteristics of La₂O₃/Al₂O₃ nanolaminates deposited by atomic layer deposition are studied by conductive atomic force microscopy working in contact mode and standard electrical characterization methods. It is found that, compared with La₂O₃/Al₂O₃ nanolaminates with LaO_x as termination, lower interface trap density, less current leakage spots, and higher breakdown voltage are obtained in the La₂O₃/Al₂O₃ nanolaminates with AlO_x as termination after annealing. A clear promotion of interface silicate layer is observed for La₂O₃/Al₂O₃ nanolaminates with AlO_x as termination compared with LaO_x as termination under the same annealing condition. In addition, the current conduction mechanism in La₂O₃/Al₂O₃ nanolaminates is considered as the Poole–Frenkel conduction. All results indicate that the AlO_x is a more appropriate termination to deposit La₂O₃/Al₂O₃ nanolaminates on Si substrate, which is useful for the high-κ process development.