Property Improvement of PLZT Capacitor Using CaRuO3 Top Electrode

Abstract

AbstractSrRuO3 and CaRuO3 films prepared by MOCVD were compared not only in term of their own properties but for their characteristics as the top electrodes of (Pb, La)(Zr, Ti)O3[PLZT] capacitor, especially for H2 degradation. Resistivity of CaRuO3 and SrRuO3 films increased after heat treatment in H2-containing atmosphere, but was recovered by a heat treatment at 600 °C under O2 atmosphere. When SrRuO3 and CaRuO3 films deposited at 600 °C were used as top electrodes, the remanent polarization(Pr) value of SrRuO3/PLZT/Pt and CaRuO3/PLZT/Pt capacitors were almost the same as the values for capacitors with a Pt top electrode. After a heat treatment in a 3 % H2 atmosphere at 200 °C, followed by one in O2 atmosphere at 450 °C, Pr value was perfectly recovered for both of SrRuO3 and CaRuO3 films. The leakage current become the smallest when using 50 nm-thick CaRuO3 film as a top electrode. Moreover, no degradation was observed for fatigue test up to 1010 cycles when MOCVD-CaRuO3 films were used as top electrodes. These data show that MOCVD-CaRuO3 film with thin thickness is a useful top electrode for PLZT capacitor.