High Temperature Barrier Electrode Technology for High Density Ferroelectric Memories with Stacked Capacitor Structure

This paper describes the novel stacked electrode structure, PtRhOx/PtRh/PtRhOx applicable to stacked memory cells in advanced ferroelectric memories. This structure acts as a stable bottom electrode and a barrier on a polysilicon plug up to 700 degrees C and a stable contact resistance of 1.5 K Ohm is obtained at the contact size of 0.6 mu m. In addition to the low leakage current of lead zirconate titanate [PZT, Pb(Zr0.52Ti0.48)O-3] capacitor (10(-8) A/cm(2) at 3 V), degradation properties of fatigue and imprint are improved compared with conventional Pt electrodes. The decrease of the switched charge is restricted to less than 10% after the fatigue cycle of 10(11). These results indicate its promise as a barrier electrode structure for advanced ferroelectric memory integration.