FERROELECTRIC PROPERTIES OF Pb(Zr, Ti)O3 CAPACITOR WITH THIN SrRuO3 FILMS WITHIN BOTH ELECTRODES

Ferroelectric properties of a Pb(Zi, Ti)O3 (PZT) capacitor with thin SrRuO3 (SRO) films within both electrodes were investigated in detail. Thin SRO films of 10 nm thickness improve the electrical performance, such as switching charge (Qsw), saturation characteristics of the hysteresis curve and imprint performance even at an elevated temperature. There was no Qsw degradation after 5 x 1010 read/write cycles at 5 V. No leakage current increase after the test was observed. The results of TEM and EDX analyses also showed that there is no diffusion of either Sr or Ru in the PZT film. The Qsw increase can be explained by the model in which excess O ions existing in the SRO films drift into the PZT due to the external electric field where they fill the O vacancies in the PZT near the interfaces. Authors confirmed that the proposed electrode structure was a key to realizing highly reliable ferroelectric random access memories (FRAMs). 5 refs.