We have investigated the effects of N+ plasma treatment and oxygen annealing on Ni/TiNiO/TaN capacitors. The postdeposition annealing of TiNiO under oxygen ambient increases the capacitance density but trades off the increased leakage current. This leakage current can be largely decreased by applying an optimized N+ plasma treatment. At high capacitance density of 17.1 fF/mu m(2), a low leakage current of 7.7 x 10(-6) A/cm(2) at 1 V is obtained indicating good potential integrated circuit application. (C) 2007 The Electrochemical Society.