Electrical properties of Ta-Sn-O firms on indium tin oxide electrodes

We have found that Ta-Sn-O films prepared on indium tin oxide (ITO) electrodes by magnetron cosputtering of Ta2O5 and SnO2 have much higher breakdown field strength than the Ta2O5 films on the ITO electrodes. The highly insulating Ta-Sn-O films were obtained in the Sn concentration range of 3-40 at. %. The figure of merit, which was defined by the multiplication of the breakdown field strength by the relative dielectric constant, of the Ta-Sn-O films was found to become a maximum in the Sn concentration of about 3 at. %. The experimental results of temperature dependence of the leakage currents indicated that the conduction mechanisms at room temperature changed from Poole-Frenkel type to Fowler-Nordheim tunneling type by adding SnO2 into Ta2O5 films. (C) 1997 American Institute of Physics.