Ferroelectricity and Oxide Reliability of Stacked Hafnium-Zirconium Oxide Devices.

In this work, we investigate the ferroelectricity of stacked zirconium oxide and hafnium oxide (stacked HfZrO) with different thickness ratios under metal gate stress and simultaneously evaluate the electrical reliability of stacked ferroelectric films. Based on experimental results, we find that the stacked HfZrO films not only exhibited excellent ferroelectricity but also demonstrated a high performance on reliability. The optimized condition of the 45% Zr proportion exhibited a robust ferroelectric polarization value of 32.57 µC/cm2, and a polarization current with a peak value of 159.98 µA. Besides this, the ferroelectric stacked HfZrO also demonstrated good reliability with a ten-year lifetime under >-2 V constant voltage stress. Therefore, the appropriate modulation of zirconium proportion in stacked HfZrO showed great promise for integrating in high-performance ferroelectric memory.

Emerging 2D Metal Oxides: From Synthesis to Device Integration.

2D metal oxides have aroused increasing attention in the field of electronics and optoelectronics due to their intriguing physical properties. In this review, an overview of recent advances on synthesis of 2D metal oxides and their electronic applications is presented. First, the tunable physical properties of 2D metal oxides that relate to the structure (various oxidation-state forms, polymorphism, etc.), crystallinity and defects (anisotropy, point defects, and grain boundary), and thickness (quantum confinement effect, interfacial effect, etc.) are discussed. Then, advanced synthesis methods for 2D metal oxides besides mechanical exfoliation are introduced and classified into solution process, vapor-phase deposition, and native oxidation on a metal source. Later, the various roles of 2D metal oxides in widespread applications, i.e., transistors, inverters, photodetectors, piezotronics, memristors, and potential applications (solar cell, spintronics, and superconducting devices) are discussed. Finally, an outlook of existing challenges and future opportunities in 2D metal oxides is proposed.

Recent advances in optical and optoelectronic data storage based on luminescent nanomaterials.

The substantial amount of data generated every second in the big data age creates a pressing requirement for new and advanced data storage techniques. Luminescent nanomaterials (LNMs) not only possess the same optical properties as their bulk materials but also have unique electronic and mechanical characteristics due to the strong constraints of photons and electrons at the nanoscale, enabling the development of revolutionary methods for data storage with superhigh storage capacity, ultra-long working lifetime, and ultra-low power consumption. In this review, we investigate the latest achievements in LNMs for constructing next-generation data storage systems, with a focus on optical data storage and optoelectronic data storage. We summarize the LNMs used in data storage, namely upconversion nanomaterials, long persistence luminescent nanomaterials, and downconversion nanomaterials, and their applications in optical data storage and optoelectronic data storage. We conclude by discussing the superiority of the two types of data storage and survey the prospects for the field.

Forming-Free SiGeOx/TiOy Resistive Random Access Memories Featuring Large Current Distribution Windows.

Optimal device integrity was achieved in Ni/SiGeOx/TiOy/TaN resistive memory by using a forming-free switch with a low switching power of 790 µW, stable endurance of 104 cycles, optimal retention time of 105 s, resistance window of at least 1150×, and tight current distributions at 85 °C. These characteristics are attributed to the low current switching obtained using SiGeOx with a high oxygen vacancy density and highly defective TiOy grain boundaries.

TiO2-Based Indium Phosphide Metal-Oxide-Semiconductor Capacitor with High Capacitance Density.

We report a low-temperature InP p-MOS with a high capacitance density of 2.7 µF/cm2, low leakage current of 0.77 A/cm2 at 1 V and tight current distribution. The high-density and low-leakage InP MOS was achieved by using high-κ TiLaO dielectric and ultra-thin SiO2 buffer layer with a thickness of less than 0.5 nm. The obtained EOT can be aggressively scaled down to < 1 nm through the use of stacked TiLaO/SiO2 dielectric, which has the potential for the future application of high mobility III-V CMOS devices.