Effect of composition of MOCVD-SrRuO₃ top electrode of (Pb, La)(Zr, Ti)O₃ capacitor on H₂ degradation

The effect of the composition of MOCVD-SrRuO₃ film was investigated not only on its property but also on the character as the top electrode of (Pb, La)(Zr, Ti)O₃[PLZT] capacitor for H₂ degradation. Resistivity of SrRuO₃ film increased by the heat treatment under H₂ contained atmosphere but was recovered by the heat treatment at 450 °C under O₂ atmosphere. When Ru excess and the stoichiometric SrRuO₃ films deposited at 600 °C were used as top electrodes, the remanent polarization(Pr) value of SrRuO₃/PLZT/Pt capacitor was almost the same as that of Pt top electrode. On the other hand, when Sr excess SrRuO₃ film was used as a top electrode, apparent Pr value decreased. After the heat treatment under 3 % H₂ atmosphere at 270°C and the following that under O₂ atmosphere at 450 °C, Pr value was perfectly recovered when using the stoichiometric SrRuO₃ film as a top electrode. However, Pr value was 50% when Ru excess SrRuO ₃ was used as a top electrode and hysteresis loops was not observed when using Sr excess SrRuO₃ as a top electrode. Moreover, no degradation was observed for fatigue test up to 10¹⁰ cycles when MOCVD-SrRuO₃ was used as a top electrode. These data showed that MOCVD-SrRuO₃ film with stoichiometric composition is a useful top electrode for PLZT ferroelectric capacitor.