Significant suppression of leakage current in (Ba,Sr)TiO3 thin films by Ni or Mn doping

Effects of Ni or Mn doping in (Ba0.5Sr0.5)TiO3 thin films on leakage current behaviors of Pt/(Ba0.5Sr0.5)TiO3/Pt capacitors were investigated. The leakage current level was found to reduce significantly after the doping over a wide range of voltages and temperatures. The leakage current in an undoped capacitor was largely governed by the Fowler-Nordheim tunneling, and its onset voltage was greatly increased in doped capacitors. The suppression of leakage current in doped capacitors appeared to be caused by a widened depletion layer, which decreases the likelihood of tunneling. (C) 2002 American Institute of Physics.