FATIGUE CHARACTERISTICS OF SOL-GEL DERIVED PB(ZR, TI)O-3 THIN-FILMS

Fatigue mechanisms of sol-gel derived Pb(Zr-Ti)O-3 (PZT) thin films and the effects of La addition on the fatigue characteristics were investigated. For PZT(40/60) and PZT(53/47), the remanent polarization (P-r) and the coercive field (E(c)) decreased with switching cycles. These properties were restored by heating the fatigued films above their Curie temperature. This result indicates that domain pinning is the dominant fatigue mechanism for PZT(40/60) and PZT(53/47). On the other hand, for PZT(70/30), P-r was almost constant and E(c) increased with switching cycles; this implies that the fatigue mechanism for PZT(70/30) is different from that for PZT(40/60) and PZT(53/47). Addition of La to the PZT(53/47) film reduced space charge in the film, though did not improve fatigue characteristics.