Characterization of laminated CeO2-HfO2 high-k gate dielectrics grown by pulsed laser deposition

The electrical and physical properties of CeO2-HfO2 nanolaminates on Si100, by pulsed laser deposition, are investigated. Layers were deposited using pure CeO2 and HfO2 targets at various substrate temperatures ranging from 220 to 620°C at Ar+H2 and O2 and in situ postdeposition anneal of nanolaminates performed by controlled cooling from deposition temperature to room temperature under high oxygen pressure. After layer growth and anneal, top and bottom Au electrodes were deposited by sputtering. Electrical characterization was done by C-V and I-V measurements. The highest k value of 30 was found for the laminates deposited at 520°C in Ar + H2 ambient. It is found that the properties of CeO2-HfO2 nanolaminates deposited at reducing atmosphere are dependent on the layer thickness. Thicker layers showed a higher dielectric constant and higher leakage current densities than thinner layers.