Low temperature processing of Nb-doped Pb(Zr,Ti)O3 capacitors with La0.5Sr0.5CoO3 electrodes

The effect of crystallization temperature on the electrical properties of sol-gel derived Pb(Zr,Ti,Nb)O3 or PNZT capacitors with La0.5Sr0.5CoO3 (LSCO) electrodes has been investigated. It is demonstrated that LSCO//PNZT(4/30/70)//LSCO capacitors can be fabricated at temperatures as low as 550°C without significant degradation in their ferroelectric and dielectric properties. Lowering the process temperature to 500°C resulted in substantial degradation in capacitor properties. Nonetheless, all capacitors processed in the 500°C to 675°C range exhibited essentially no fatigue up to 5×109 switching cycles. The low temperature processing is significant as it indicates that this ferroelectric capacitor technology is compatible with high density nonvolatile memory architectures. In other words, these process temperatures are low enough to maintain plug integrity and to prevent degradation of the underlying CMOS circuitry in a high density ferroelectric memory.