Electrical Properties of Al₂O₃ Incorporated CeO₂ Thin Films Deposited by RF Magnetron Sputtering

Abstract

The Al2O3 incorporated CeO2 thin films (Al2O3 molar fraction of 0.0 to 0.6) were prepared by the RF magnetron sputtering with the combinatorial mask system using the two targets of Al2O3 and CeO2 in Ar + 10% O2. The deposited films were annealed in N2 and O2 at 500°C for 30 minutes. The minimum leakage current density of 1.6 x 10-8 A/cm2 measured at the electric field of 1MV/cm was obtained for the N2 annealed sample with the Al2O3 incorporation of 0.2, which value was significantly lower than that of the film without the Al2O3 incorporation by two orders of magnitude. The variation of the flat band voltage with the incorporated Al2O3 molar fraction suggested the generation of the fixed positive charge, which was probably arisen from the lower Ce oxide in the film and/or the lower oxide of Si diffused from the substrate into the film.