The relationship between the memory retention properties and the leakage current density of Pt/YMnO3/Y2O3/Si capacitors was discussed. The leakage current of the ferroelectric YMnO3 layer was varied by temperature and by annealing the capacitors. It was found that the retention time became shorter upon increasing the leakage current density at the retention voltage. The retention time was prolonged from about 103 to up to 104 s when the leakage current density was reduced to 2×10−9 A/cm2 by annealing under N2 ambient. The analysis of the leakage current revealed that the retention degradation mechanism was related to the Schottky emission. From the temperature dependence of the leakage current and the pseudo isothermal capacitance transient spectrum, it was found that applied voltage with an unnecessarily long time to polarize the ferroelectric layer generated Frenkel defects in the ferroelectric layer, and that the amount of the defects greatly affected the memory retention time. These results suggest that to improve the memory retention properties, reducing the defect density of the ferroelectric layer is important, as well as lowering the Schottky current.
No takes yet. Share an insight, caveat, or question.
Ito et al. (2003) studied this question.