Diffusion barrier performance of novel RuTiN material for high-density volatile memory capacitor

The electrical properties for the new RuTiN barrier material were investigated and compared with those for the TiN barrier. In case of the TiN barrier in the sputtered-(Ba,Sr)TiO₃ simple stack-type structure, the TiN film was partially oxidized in the as-deposited state and was almost completely oxidized at 550 °C, leading to a degradation of the capacitance. In contrast, the new RuTiN barrier was not oxidized up to 600 °C, and exhibited an improved capacitance of >30 fF/cell, although the leakage current is very high (∼10^-9 A/cell) due to low work function (4.43 eV). Correspondingly, the diffusion barrier performance of new RuTiN film, as an oxygen diffusion barrier for high-density volatile capacitor, is better than that of the TiN barrier.