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

Abstract

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.