Improved Ferroelectric Performance of Mg-Doped LiNbO(3) Films by an Ideal Atomic Layer Deposited Al(2)O(3) Tunnel Switch Layer.

Bilayer structures composed of 5% Mg-doped LiNbO(3) single-crystal films and ultrathin Al(2)O(3) 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 Al(2)O(3), 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 Al(2)O(3) layer blocks the adverse effects such as by-electrode charge injection and improves the fatigue endurance properties of Mg-doped LiNbO(3) ferroelectric capacitors. This study provides a possible way to improve the reliability properties of ferroelectric devices in the non-volatile memory application.