Study of the electronic conduction mechanism in Nb-doped SrTiO3 thin films with Ir and Pt electrodes

Strontium titanate (ST) is an attractive material for dynamic random access memory applications. Doping ST with other elements such as Nb has been shown to reduce problems such as frequency dispersion and resistance degradation associated with this material. In this report, we study the electronic conduction mechanism in Nb-doped ST films [Sr(Ti1-xNbxO3)] with Ir and Pt electrodes. Film thicknesses were of the order of 35-40 nm. It was found that the "true" leakage current satisfied both Schottky and Frenkel-Poole conduction mechanism equations for both positive and negative polarities. The effect of Nb content (x = 0, 0.001, 0.01, and 0.05) on the barrier heights using both the mechanisms were determined. It was found that the barrier height decreased with increased Nb content, which was correlated with the increase in leakage current. (C) 2000 American Institute of Physics. [S0003-6951(00)05436-X].