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

Abstract

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.