Influence of interface layer composition on the electrical properties of epitaxial Gd2O3 thin films for high-K application

The authors report on the impact of interface layer composition on electrical properties of epitaxial Gd2O3 thin films on Si(001) substrates. The electrical properties of epitaxial Gd2O3 thin films were improved significantly by controlled modification of interface layer composition. The minimum capacitance equivalent thickness estimated for Pt∕Gd2O3∕Si metal oxide semiconductor structures was as low as 0.76nm with leakage current density of 15mA∕cm2 at (Vg−VFB)=1V. The corresponding density of interface states was found to be 2.3×1012cm−2eV−1. The authors also find that a change in the interface layer composition significantly alters band alignment of Gd2O3 layer with respect to Si substrates.