Asymmetric Hysteresis Loops and Leakage Current Behaviors in Au/PZT/Pt/Al_2O_3/SiO_2/Si Thin Films Prepared by MOCVD Method

摘要

The polarization-voltage (P-V) and leakage currents density (J-V) characteristics were investigated on the ferroelectric PZT films deposited on Pt/A_l2O_3/SiO_2/Si substrate with a vapor-deposited gold top electrode. The P-V hysteresis loops and the J-V characteristics were measured after performing a rapid thermal annealing (RTA) process. A ferroelectric test system (Precision LC Radiant Technology) was used to measure their electrical properties with a 90-nm PZT thickness and an area of 7.85×10~(-5) cm~2. The measurements were taken by connecting a Pt bottom electrode to the drive of the precision LC and the Au top electrode to the drive of the precision LC. The P-V hysteresis and J-V characteristics of PZT samples showed the asymmetry for both measurements. The asymmetric hysteresis loops and leakage current behavior were shifted in the positive direction when the drive was applied to the Pt electrode, while being negatively shifted in the converse case. The asymmetric behavior of the polarized state in the hysteresis loops due to the electrode configuration resulted from different work function between the Pt and Au electrodes, further influencing the leakage current behavior.