Wake-up effect in Hf_(0.4)Zr_(0.6)O_(2) ferroelectric thin-film capacitors under a cycling electric field

We examined the wake-up effect in a Ti N/Hf_(0.4)Zr_(0.6)O_(2)/TiN structure.The increased polarization was affected by the cumulative duration of a switched electric field and the single application time of the field during each switching cycle.The space-charge-limited current was stable,indicating that the trap density did not change during the wake-up.The effective charge density in the space-charge region was extracted from capacitance-voltage curves,which demonstrated an increase in free charges at the interface.Based on changing characteristics in these properties,the wake-up effect can be attributed to the redistribution of oxygen vacancies under the electric field.