Gadolinium oxide high-k gate dielectrics prepared by anodic oxidation

The growth and properties of gadolinium oxide (Gd2O3) films prepared by anodic oxidation were investigated. Uniform Gd2O3 thin film with good oxide quality was obtained. The X-ray diffraction (XRD) pattern of the Gd2O3 films showed that they had a poly-crystalline structure. The dielectric constants of Gd2O3 films oxidized at 30 and 60 V are 9.4 and 12.2, respectively. The equivalent oxide thickness (EOT) of the Gd2O3 stacked oxide is in the range of 5.8-9.4 nm. The MOS capacitor with Gd2O3 exhibits interesting electrical properties. Longer oxidation time reduced the leakage current density for 30 V anodic oxidation but increased the leakage current density for 60 V anodic oxidation. This work reveals that Gd2O3 could also be an alternative dielectric for Si substrate and therefore, might pave the way to fabricate CMOS devices in the future.