Composition and electrical characteristics of Al2O3–HfO2–HfTiO nanolaminates on Si

A dielectric constant of 27 was demonstrated in the as deposited state of a 5 nm thick, seven layer nanolaminate stack comprising Al2O3, HfO2 and HfTiO. It reduces to an effective dielectric constant (keff) of ∼14 due to a ∼0.8 nm interfacial layer. This results in a quantum mechanical effective oxide thickness (EOT) of ∼1.15 nm. After annealing at 950 °C in an oxygen atmosphere keff reduces to ∼10 and EOT increases to 1.91 nm. A small leakage current density of about 8 × 10−7 and 1 × 10−4 A/cm2, respectively at electric field 2 and 5 MV/cm and a breakdown electric field of about 11.5 MV/cm was achieved after annealing at 950 °C.