Physical and electrical properties of bilayer CeO2/TiO2 gate dielectric stack

Abstract

This study demonstrates a bilayer gate oxide structure of cerium oxide deposited via pulsed laser deposition and titanium oxide using conventional atomic layer deposition. Samples were deposited on p-type Si (100) substrate and exhibit interesting physical and electrical properties such that 600 °C annealed CeO2/TiO2 samples having κ-value of 18 whereas pure CeO2 deposited samples have dielectric constant of 17.1 with leakage current density of 8.94 × 10−6 A/cm2 at 1 V applied voltage. The result shows promising usage of the synthesized rare earth oxides as gate dielectric where ideal κ-value and significant reduction of the leakage current by 5 orders of magnitude is achieved.Leakage current conduction mechanism for as-deposited sample is found to be dominated by Poole–Frenkel (PF) emission; the trap level is found to be at 1.29 eV whereas annealed samples (600 °C and 800 °C) exhibited Schottky emission with trap levels at 1.45 eV and 0.81 eV, respectively.