TiNx/Hf0.5Zr0.5O2/TiNx ferroelectric memory with tunable transparency and suppressed wake-up effect

Abstract

The discovery of HfO2-based ferroelectric (FE) films gives FE memory devices great potential for the next-generation memory technology. In this letter, TiNx with varying nitrogen atomic contents was demonstrated as electrodes of FE Hf0.5Zr0.5O2 memory devices on quartz substrates for transparent memory applications. The transmittance and reflectance from 350 nm to 2500 nm of the TiNx/Hf0.5Zr0.5O2/TiNx structures generally increased and decreased, respectively. Selectivity between the visible and infrared light altered as the N content is increased. When the N2 ratio increases from 0% to 30%, the transmittance selectivity between 1064 nm (infrared) and 532 nm (green) lights increases from 79.6% to 105.3%, while the reflectance selectivity decreases from 107.9% to 48.9%. The polarization cycling performance of FE TiNx/Hf0.5Zr0.5O2/TiNx was explored up to 107 times. The devices with N-rich TiNx electrodes showed suppression of the wake-up effect during cycling. The transient current loops and atomic-fraction depth profiles of capacitors were inspected as well. The results indicated that there were fewer oxygen-vacancy defects in the as-grown N-rich devices and no influential redistribution of oxygen-vacancy defects during the cycling.