I-V characteristics of tantalum oxide film and the effect of defects on its electrical properties

In the work, tantalum oxide (TaOx) films were prepared by pulsed DC reactive magnetron sputtering method on Si wafer, corning glass and carrier glass. Ta/tantalum oxide/Ta (metal-insulation-metal, MIM) structures were fabricated to investigate the I-V characteristics of tantalum oxide films. I-V characteristics of MIM capacitors with top-electrode diameters varying from 1 to 4 mm were investigated. Symmetry and zero shifting phenomenons of I-V curves were studied. The effect of substrate roughness on the electrical properties of MIM capacitors was examined. The results show with the increase of top-electrode diameters from 1 to 4 mm the breakdown field strengths decreased from 2.22 to 0.3 MV/cm and the leakage current density at 0.25 MV/cm increased from 1.5E-9 to 7.3E-5 A/cm(2). The roughness of the substrate and films, and defects in the films have great effect on the quality and I-V characteristics of MIM capacitors. (C) 2003 Elsevier B.V. All rights reserved.