Improvement in Al2O3 dielectric behavior by using ozone as an oxidant for the atomic layer deposition technique

We have prepared Al₂O₃ films by the atomic layer deposition technique using trimethylaluminum as the precursor for aluminum and O₃, instead of commonly used H₂O, as an oxidant. We show that even without any postdeposition annealing or any preventive layer between the Al₂O₃ film and Si substrate to suppress the formation of metallic clusters, the Al₂O₃ films prepared using O₃ have significantly less amount of defect states like Al-Al and OH bonds compared with those prepared by H₂O. The films show device quality leakage characteristics, with Al₂O₃ film prepared with O₃ showing a leakage current density one or two orders lower and a smaller flatband voltage shift than that of Al₂O₃ film prepared with H₂O, demonstrating improved interface characteristics. The former also shows a very low wet etch rate.