LA0.5SR0.5COO3 ELECTRODE TECHNOLOGY FOR PB(ZR,TI)O-3 THIN-FILM NONVOLATILE MEMORIES

Oxide electrode technology is investigated for optimization of Pb(Zr,T i)O-3 (PZT) thin film capacitor properties for high density nonvolatil e memory applications. PZT thin film capacitors with RF sputter deposi ted La0.5Sr0.5CoO3 (LSCO) electrodes have been characterized with resp ect to the following parameters: initial dielectric hysteresis loop ch aracteristics, fatigue performance, microstructure and imprint behavio r. Our studies have determined that the fatigue of PZT capacitors with LSCO electrodes is less sensitive to B site cation ratio and underlyi ng electrode stack technology than with RuO2 electrodes. Doping PZT th in films with Nb (PNZT) improves imprint behavior of LSCO/PZT/LSCO cap acitors considerably. We have demonstrated that PNZT 4/30/70//LSCB cap acitors thermally processed at either 550 degrees C or 675 degrees C h ave almost identical initial hysteresis properties and exhibit essenti ally no fatigue out to approximately 10(10) cycles.