Electrical properties of TaSnO films on indium tin oxide electrodes

We have found that TaSnO films prepared on indium tin oxide (ITO) electrodes by magnetron co-sputtering 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 to 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 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.