Electrical properties of thin Ta 2O 5 films obtained by thermal oxidation of Ta on Si

Abstract

Tantalum pentoxide films (13–260 nm) on p-type Si have been prepared by thermal oxidation at 673–873 K of rf sputtered Ta films and have been studied using Al–Ta 2O 5–Si capacitors. Both dielectric constant and refractive index were found to depend on the thickness of the Ta 2O 5 layers. Layers with a dielectric constant of 25–32 were obtained. A decreasing trend in the leakage current was found upon increasing oxidation temperature from 673 to 873 K. Leakage current density of (10 −8 to 3×10 −7) A cm −2 at 1 MV cm −1 effective field was achieved.