Advanced high-k gate dielectric amorphous LaGdO3 gated metal-oxide-semiconductor devices with sub-nanometer equivalent oxide thickness

Abstract

Careful selection of pulsed laser deposition conditions was executed to achieve sub-nanometer EOT (equivalent oxide thickness) in amorphous LaGdO3 based high-k/metal gate stacks. The lowest EOTs attained were ∼5.4 Å and 8.4 Å with and without quantum mechanical correction, respectively. The electrical measurements yielded a high permittivity of 20.5 ± 2.4, a thin bottom interfacial layer of thickness 4.5 ± 1 Å, and interface (cm−2 eV−1) and fixed (cm−2) charge densities of ∼1012. Analysis of temperature dependent leakage currents revealed that gate injection current was dominated by Schottky emission below 1.2 MV/cm and quantum mechanical tunneling above this field. The physical origin of substrate injection was found to be a combination of Schottky emission and trap assisted tunneling.