Search

In this study, the influence of the HfOxNy interfacial layer (IL), interposed between the atomic layer deposited ferroelectric (FE) Hf0.5Zr0.5O2 thin film and TiN top electrode, on the FE properties of such a film was examined. The HfOxNy IL decreased the relative proportion of the non-FE monoclinic phase, possibly due to the N-doping effect. Furthermore, the oxidation of the TiN top electrode was also suppressed by the sacrificial oxidation of the HfOxNy IL during the rapid thermal process. As a result, the double remanent polarization of a Hf0.5Zr0.5O2 thin film could be enhanced from 40.2 to 48.2 μC/cm2 by the positive-up-negative-down test, and its degradation by fatigue during the endurance test can also be decreased. This result demonstrates the significance of interfacial engineering to optimize the FE properties of Hf0.5Zr0.5O2 films. [ABSTRACT FROM AUTHOR]

The influence of La content on the ferroelectric properties of HfO2-ZrO2 thin films was examined for integrated electrostatic supercapacitor applications. A transition from ferroelectric to antiferroelectric-like behavior, accompanied by a significant increase of energy storage density value and efficiency, was observed with the increasing La concentration in La-doped HfO2-ZrO2-based capacitor structures, where the processing temperature remained below 400 °C. The combination of high energy storage density value (≈50 J/cm3) with high efficiency (70%) was obtained for the film with the highest La content (2.0 mol. %). The 2.0 mol. % La-doped HfO2-ZrO2-based capacitor structures were field cycled up to 109 times and were found to provide >40 J/cm3 energy storage density along with up to 80% efficiency. Moreover, the high thermal stability of such capacitors was confirmed. The founded property combination makes the La-doped HfO2-ZrO2 thin films suitable for integrated energy storage and pulse-power devices. [ABSTRACT FROM AUTHOR]

Thin metal interfacial layers (1-nm-thick Ti and Hf) were exploited as the appropriate interfacial layer for forming an interfacial (buffer) layer between the 10-nm-thick Ta2O5 resistance switching layer and the Ta electrode to enhance the switching cycle endurance and uniformity. The thin metal interfacial layers were in-situ oxidized to TiOx (x < 2) and HfO2 layers, respectively, during the ion beam sputter deposition on the Ta2O5 layer. Compared with the devices with no interfacial layers, the switching uniformity was improved for both interfacial layers, with Ti showing the greatest improvement. The switching cycle endurance was largely degraded for the HfO2 interfacial layer, whereas the TiOx interfacial layer greatly improved in such aspects. The appropriate level of Ti-O bond energy and an excessively high Hf-O bond energy were suggested as the main reasons for such a critical difference. [ABSTRACT FROM AUTHOR]