Adjustable onset voltages of embedded LiNbO3 domain-wall selectors for large-scale memory integration

Abstract

A ferroelectric domain-wall memory has dual functionalities, where the volatile interfacial domain nearby the electrode can function as an embedded selector in contrast to the nonvolatile domain within an inner cell for information storage. However, most of crossbar memories require independent adjustments of the onset voltage of the selector and the coercive voltage of the inner domains at the same node fabrication technology. Here, we fabricated a LiNbO3 mesa-like domain-wall device to touch two top-to-top triangular-like Cu side electrodes. The readout wall current is more than 40 μA in write time as short as 20 ns. With the reduction of the apex angle of the Cu electrode from 180° to 30°, the onset voltage increases continuously from 0.68 to 3.05 V irrespective of the coercive voltage along with the improvement of polarization retention. The underlying physics is discussed on thickening of an effective interfacial layer projected along the applied electric-field direction. This finding enables the crossbar connection of high-density ferroelectric domain-wall memory.