Study of the electronic conduction mechanism in Nb-doped SrTiO3 thin filmswith 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 sho wn to reduce problems such as frequency dispersion and resistance degradati on associated with this material. In this report, we study the electronic c onduction mechanism in Nb-doped ST films [Sr(Ti1-xNbxO3)] with Ir and Pt el ectrodes. Film thicknesses were of the order of 35-40 nm. It was found that the "true" leakage current satisfied both Schottky and Frenkel-Poole condu ction mechanism equations for both positive and negative polarities. The ef fect of Nb content (x = 0, 0.001, 0.01, and 0.05) on the barrier heights us ing both the mechanisms were determined. It was found that the barrier heig ht decreased with increased Nb content, which was correlated with the incre ase in leakage current. (C) 2000 American Institute of Physics. [S0003-6951 (00)05436-X].