Search

Energy storage devices with high energy storage density (UESD), fast operating speed, and high output power are indispensable for modern energy needs. This study presents a wafer-scale epitaxial antiferroelectric ZrO2/TiN heterostructure with a state-of-the-art high UESD of ∼118.6 J cm−3. This significant UESD originates from the predominant [110] antiferroelectric polar axis of ZrO2 oriented out-of-plane, which is confirmed by macroscopic and microscopic analyses of the epitaxial relationships. The construction of a coincidence site lattice indicates the low lattice mismatch between ZrO2(110) and TiN(111). The stacking of ZrO2 sublayers demonstrates the importance of precise epitaxy in controlling crystal orientation, minimizing leakage current, and improving antiferroelectric characteristics. Furthermore, the epitaxial growth of ZrO2 enables a clear observation of inductive-like negative capacitance response, providing insights into antiferroelectric dynamics. The high UESD highlights the significance of atomic layer epitaxy for high-quality antiferroelectric heterostructures, particularly in epitaxial growth methods and energy storage applications. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the indirect effects on the properties of ZrO2 films deposited by atomic layer deposition (ALD) when an Mg-Ca alloy is modified through equal-channel angular pressing (ECAP) following extrusion. The study aims to understand how the increase in CaO content in the native oxide layer of the Mg-Ca alloy influences the crystallinity and defect density of the ZrO2 film. Consequently, the corrosion protection performance of the ZrO2 film is enhanced by 1.2 to 1.5 times. A reduction in the anti-scratch property of the ZrO2 film was also observed, with a critical load reduction of 34 μN. This research provides a detailed analysis of the modifications induced by ECAP on the as-extruded Mg-Ca alloy and its subsequent impact on the properties of the ZrO2 film. [ABSTRACT FROM AUTHOR]

In this study, platinum (Pt) and tungsten (W), two materials with dissimilar coefficients of thermal expansion (CTE) and work functions (WF), are used as the top electrode (TE) and the bottom electrode (BE) in metal/ferroelectric/metal (MFM) structures to explore the ferroelectricity of hafnium zirconium oxide (HZO) with a thickness less than 10 nm. The electrical measurements indicate that a higher CTE mismatch between HZO and TE/BE is beneficial for enhancing the ferroelectric properties of nanoscale HZO thin films. The different WFs of TE and BE generate a built-in electric field in the HZO layer, leading to shifts in the hysteresis loops and the capacitance–voltage characteristics. The structural characterizations reveal that the preferred formation of the orthorhombic phase in HZO is dominated by the W BE. The device in which W is used as the TE and BE (the W/HZO/W MFM structure) presents the optimal ferroelectric performance of a high remanent polarization (2 P r = 55.2 μ C cm−2). The presence of tungsten oxide (WO x ) at the W/HZO interfaces, as revealed by high-resolution transmission microscopy, is also responsible for the enhancement of ferroelectric properties. This study demonstrates the significant effects of different CTEs and WFs of TE and BE on the properties of ferroelectric HZO thin films. [ABSTRACT FROM AUTHOR]

In this article, aluminum nitride (AlN) resistive random access memory (RRAM) devices are fabricated and investigated. To improve the resistive switching performance, the atomic layer annealing (ALA) technique, which is an energy transfer process by the in situ plasma treatment introduced into atomic layer deposition, was used to modulate the film quality of the AlN switching layer with a thickness of only 3.3 nm. The ALA treatment is capable of tailoring nitrogen vacancies in the AlN layer with monolayer accuracy, leading to a decrease in the operating voltage and an improvement in uniformity of the resistive switching characteristics. In addition, the AlN RRAM devices exhibit pulse endurance over 104 cycles and retention of more than 106 s at 125 °C. The result demonstrates that the resistive switching properties of RRAMs can be controlled by the precise atomic layer engineering of each monolayer. [ABSTRACT FROM AUTHOR]