Improved Ferroelectric Performance of Mg-Doped LiNbO₃ Films by an Ideal Atomic Layer Deposited Al₂O₃ Tunnel Switch...

Bilayer structures composed of 5% Mg-doped LiNbO₃ single-crystal films and ultrathin Al₂O₃ layers with thickness ranging from 2 to 6 nm have been fabricated by using ion slicing technique combined with atomic layer deposition method. The transient domain switching current measurement results reveal that the P-V hysteresis loops are symmetry in type II mode with single voltage pulse per cycle, which may be attributed to the built-in electric field formed by asymmetric electrodes and compensation of an internal imprint field. Besides, the inlaid Al₂O₃, as an ideal tunnel switch layer, turns on during ferroelectric switching, but closes during the post-switching or non-switching under the applied pulse voltage. The Al₂O₃ layer blocks the adverse effects such as by-electrode charge injection and improves the fatigue endurance properties of Mg-doped LiNbO₃ ferroelectric capacitors. This study provides a possible way to improve the reliability properties of ferroelectric devices in the non-volatile memory application.