The RuTiN material, as a new oxygen diffusion barrier for high density volatile and nonvolatile memory capacitors, was proposed. In case of the TiN barrier in the physical vapor deposited barium strontium titanate simple stack-type structure, capacitance initially decreased more than 50% after annealing at 500degreesC, compared to that at 450, and 550degreesC, about zero, due to oxidation of the TiN barrier. However, the new RuTiN barrier was not oxidized up to 600degrees C, and showed a better capacitance property of more than 28 fF/cell, although the leakage current property is very high due to low work function. Therefore, new RuTiN film, as a diffusion barrier for oxygen, is very promising material to achieve high density capacitors. (C) 2002 The Electrochemical Society.