CoTiO3 high-κ, dielectrics on HSG for DRAM applications

In this paper, a new high-kappa dielectric CoTiO3 has been investigated for the first time on hemispherical grained (HSG) poly-Si dynamic random access memories capacitors. Three types of HSG were prepared. We found that capacitors with maximum grain size and the highest density exhibit twice the capacitance of the others. The dielectric constant for CoTiO3 was estimated to be larger than 50. Leakage current measurements performed at temperatures as high as 100degreesC show that this dielectric is stable. The polarity dependence is found to be due to the different barrier heights with the nitride barrier. A leakage mechanism is proposed for this polarity dependence.