Data retention in organic ferroelectric resistive switches

Abstract

Solution-processed organic ferroelectric resistive switches could become the long-missing non-volatile memory elements in organic electronic devices. To this end, data retention in these devices should be characterized, understood and controlled. First, it is shown that the measurement protocol can strongly affect the 'apparent' retention time and a suitable protocol is identified. Second, it is shown by experimental and theoretical methods that partial depolarization of the ferroelectric is the major mechanism responsible for imperfect data retention. This depolarization occurs in close vicinity to the semiconductor-ferroelectric interface, is driven by energy minimization and is inherently present in this type of phase-separated polymer blends. Third, a direct relation between data retention and the charge injection barrier height of the resistive switch is demonstrated experimentally and numerically. Tuning the injection barrier height allows to improve retention by many orders of magnitude in time, albeit at the cost of a reduced on/off ratio. Corresponding Author

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

“…This behavior is in marked contrast to that observed on the phase separated memory diodes mentioned above where the depolarization under supportive bias continues to occur, albeit at a lower rate than when the device is grounded. 40 We attribute this difference to the very different depolarization mechanism in both systems: minimization of the energy associated with the stray field in non-ferroelectric domains versus R-relaxation. The applied supportive electric field in our experiment (Fig.…”

“…Inspired by the strong positive effect the application of a supportive bias was found to have on the retention of blended ferroelectric-semiconductor resistive memory diodes, 40 we repeated the retention experiments while applying a supportive bias of 10 V mm À1 ({E c ) to the device during the waiting time between poling and readout. For all materials the retention is heavily affected by the supportive field, even though this field is significantly lower than the coercive field, see the open symbols in Fig.…”

Tuning the Ferroelectric Properties of Trialkylbenzene‐1,3,5‐tricarboxamide (BTA)

“…After 10 5 cycles the polarization decreased by a factor two as compared to the initial value (Figure S13, Supporting Information). Together with the remnant polarization, coercive field, polarization switching time, and data retention being already comparable to the performance of P(VDF:TrFE) thin film devices, this makes BTA‐C6 interesting not only from a scientific, but also from an application point of view.…”

Ferroelectricity in Polar Polymer‐Based FETs: A Hysteresis Analysis

“…Ferroelectric memory based on polar polymers has attracted a lot of interest in the past few decades [1–5] due to their low-cost applications for flexible electronics and the potential ease of low temperature processing. The most common configuration investigated is the ferroelectric field effect transistor (FeFET) with the polar polymer incorporated as the gate dielectric.…”