Retention properties with high‐temperature resistance in (Bi,Pr)(Fe,Mn)O₃ thin film capacitor

Abstract

(Bi0.9Pr0.1)(Fe0.97Mn0.03)O3 (BPFM) thin film was deposited on Pt-coated Si(100) substrate by chemical solution deposition. Remnant polarization and coercive field in the BPFM film capacitor were 113 µC/cm 2 and 630 kV/cm at the maximum electric field of 1000 kV/cm, respectively. Switching charge measured by a rectangular pulse measurement was 118 µC/cm 2 . Almost no polarization losses of BPFM film capacitor was observed even after retention time of 10 4 s at RT. Furthermore, the polarization loss at 450 °C was only 3.7 % even after 10 4 s. These results indicate that BPFM film capacitor is suitable for non-volatile memory applications at high temperature.Copyright line will be provided by the publisher Ferroelectric random access memory (FeRAM) is one of the promising candidates for non-volatile memories because of its high speed, low power consumption and compatibility to current electrically erasable programmable read only memory (EEPROM) devices. Recently, FeRAM attempts to go to the medical field using the radiation hardness of the ferroelectric domain. The stability of remnant polarization over a wide temperature range is considered as one of the important factors for more expanded ferroelectric memory application areas. For instance, in a special memory application area, there are demands to storage archives for longer period over 100 years withstanding the temperature fluctuation. Besides, retention at higher temperatures for ID tag is required in heat treatment line at the factory of various products. Thus, superior data retention performance at higher temperature is required for more expanded application areas of FeRAM devices.Generally, the amount of polarization charge decreases when the ferroelectric capacitor is kept for a long time after the polarization is completed. When the amount of polarization charge eventually decreases below a threshold level of FeRAM device, the memory of the bit is lost. Hence, polarization loss is considered to be an important issue for the expanded FeRAM application area over wide range of temperature.As a ferroelectric material for FeRAM applications, Pb(Zr,Ti)O3 (PZT) is well known because of its high remnant polarization, low coercive field and low processing temperature [1][2][3]. However, it is known that remnant polarization in PZT film capacitors shows serious polarization loss at high temperature [4][5][6]. Many researchers have focused on revealing the mechanism of polarization loss [4,[6][7][8][9][10][11][12]. It was explained that the internal field, which is formed by redistribution of defects charges near the interface between electrodes and ferroelectric layer, initiates the polarization back-switching during the retention time. Then, the amount of polarization charge decreased due to the polarization back-switching generated by the internal fields [4,6,13]. Furthermore, PZT thin films showed serious polarization losses at high temperature due to their weak heat-resistance [4][5][6]. Note that this polarization loss was also observed in other ferroelectr...

Polarization loss in the organic ferroelectric trialkylbenzene-1,3,5-tricarboxamide (BTA)

“…E c E 50 V mm À1 and P r E 85 mC m À2 found for P(VDF:TrFE) at room temperature, 29 for which thin film polarization retention times in the order of several hours have been reported, [30][31][32] and compared to inorganics like BFO and PZT where E c E 50 V mm À1 , P r E 1000 mC m À2 and retention times in thin film can be over 10 4 s with an energy barrier W b = 1.25 eV. 33,34 To further interpret the data in Fig. 3, we use the model by Vopsaroiu et al for the depolarization switching time t sw .…”

Temperature dependence of ferroelectric properties and the activation energy of polarization reversal in (Pr,Mn)‐codoped BiFeO3 thin films

“…Thus, it is expected that BFO thin films achieve the superior retention properties compared with other ferroelectric materials such as PZT and SBT thin films. In fact, we have demonstrated the superior retention properties with high‐temperature resistance in (Pr,Mn)‐codoped BiFeO 3 thin‐film capacitors . The origin of their superior high‐temperature resistance has, however, not been revealed.…”

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