Growth and electrical characteristics of rf magnetron sputtered Ta2O5 films on Si

Rf magnetron sputter technique was used for deposition of Ta2O5 films on silicon (111) and quartz substrates by sputtering of tantalum target under various oxygen partial pressures in the range 5x10(-5)-5x10(-4) mbar and at a substrate temperature of 673 K. The effect of oxygen partial pressure on the chemical binding configuration, crystal structure, electrical and optical properties was investigated. The X-ray photoelectron spectra revealed that the films formed at oxygen partial pressure >= 1x10(-4) mbar were stoichiometric. The dielectric constant increased from 17 to 22 by increasing the oxygen partial pressure from 5x10(-5) to 5x10(-4) mbar due to the improvement in the crystallinity and packing density of the films. The single phase films formed at an oxygen partial pressure of 1x10(-4) mbar showed low leakage current density of 4x10(-9) A/cm(2). The optical band gap of the films increased from 4.36 to 4.44 eV with the increase of oxygen partial pressure.