Enhancement of the Retention Characteristics in Solution-Processed Ferroelectric Memory Transistor with Dual-Gate Structure.

We demonstrated the enhancement of the retention characteristics in solution-processed ferroelectric memory transistors. For enhanced retention characteristics, solution-processed Indium Gallium Zinc Oxide (InGaZnO) semiconductor is used as an active layer in a dual-gate structure to achieve high memory on-current and low memory off-current respectively. In our dual-gate oxide ferroelectric thin-film transistor (DG Ox-FeTFT), while conventional TFT characteristic is observed during bottom-gate sweeping, large hysteresis is exhibited during top-gate sweeping with high memory on-current due to the high mobility of the InGaZnO. The voltage applied to the counter bottom-gate electrode causes variations in the turn-on voltage position, which controlled the memory on- and off-current in retention characteristics. Specifically, due to the full depletion of semiconductor by the high negative counter gate bias, the memory off-current in reading operation is dramatically reduced by 10⁴. The application of a high negative counter field to the dual-gate solution-processed ferroelectric memory gives a high memory on- and off-current ratio useful for the production of high performance multi-bit memory devices.