Dysprosium Scandate Thin Films Prepared by Metal Organic Chemical Vapor Deposition on Pt/TiOx/SiO2/Si Substrates for MIM Capacitor Applications.

Abstract

DyScO3 thin films having thickness between 8 and 38 nm were grown on Pt/TiOx/SiO2/Si(100) substrates by metal organic chemical vapor deposition. Thickness dependent crystallization was observed and thicker films were polycrystalline at 700 oC. Root mean square roughness of the films having thickness 20 nm was around 1-1.5 nm, comparable with the underlying Pt film. Experimentally extracted dielectric constant of the films was ~ 21{plus minus}1.5 which is comparable to the dielectric constant (24) of DyScO3 calculated from the Clausius-Mosotti equation using the molecular polarizabilites of Dy2O3 and Sc2O3. Electrical properties are promising: ~8 nm thick DyScO3 film reached an equivalent SiO2 thickness (EOT) of ~1.95 nm. Dielectric breakdown of the film was 2.3 MV/cm and the corresponding energy density is around 5 J/cm3. For the amorphous films leakage current density through the metal-insulator-metal stacks were in the range 10-4 to 10-7 A/cm2 at an electric field of about 1 MV/cm.