Size and top electrode-edge effects on fatigue in Pb(Zr,Ti)O-3 capacitors with Pt-electrodes

The occurrence of switching-induced suppression of the remanent polarization (fatigue) in Pb(Zr,Ti)O-3 (PZT) ferroelectric capacitors with comb shaped top electrodes was studied by means of scanning force microscopy assisted by a lock-in amplifier. Fatigue occurs earlier in capacitor with narrower comb-fingers, mainly in the central part of the fingers. In addition to this size effect, electrode-edge effects could be observed. Along the edges, in an area of about 250nm width, the preferential direction of the blocked polarization is opposite to that in the center of the comb fingers; in this area, fatigue occurs generally one to two cycle-decades later. Self-recovery effects were also localized to mainly occur near the edges of the electrodes. The mechanism of these results is discussed on the basis of fringe field and stress at top electrode edge.