Polarity-dependent rejuvenation of ferroelectric properties of integrated SrBi2Ta2O9 capacitors by electrical stressing

The electric-field-induced rejuvenation behavior of the degraded ferroelectric properties of integrated ${\mathrm{Pt/SrBi}}_{\mathrm{2}}{\mathrm{Ti}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{9}}/\mathrm{Pt}$ capacitors was investigated. Integration processes, especially plasma-enhanced chemical vapor deposition of the passivation layers, generate hydrogen ions and electrons which act as domain pinning centers and a source of a negative internal electric field. Domain pinning was found to reduce the remanent polarization ${\mathrm{(P}}_r)$ and internal field that induces an imprint to the positive bias direction. Alternating current cyclings with peak voltages of +/−6 V rejuvenated the degraded ferroelectric performance of the capacitors. Cycling with a negative bias was more effective in fixing the damage than was a positive bias. Baking at 125 °C again degraded the rejuvenated ferroelectric performance. The degree of re-degradation was also dependent on the polarity of the rejuvenating bias. The polarity-dependent behavior of rejuvenation was explained on the basis of a negative-internal-field model due to preferential capture of electrons from the plasma at the top electrodes.