•Fabrication BiSe-based SOT devices with ultra-thin insertion layers of Pt, Cu and Ta.•Investigating the role of these insertion layers on the SOT performance.•Quantifying the SOT performance using ...X-ray and transport measurements.
The way inter-mixing chemical state influences the damping-torque efficiency of a spin–orbit torque (SOT) heterostructure is a matter of debate. This is because it acts as a local symmetry-breaking that differs from the global symmetry-breaking at the interface. A combination of angle-resolved X-ray photoelectron spectroscopy (AR-XPS), X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) was utilized to investigate the composition-gradient effects on the damping-torque efficiency of the Bi2Se3/insertion (Ta, Pt, Cu)/CoFeB SOT devices, with the insertion to be 0.5 and 1.0 nm. These embedded metals have the advantages of (i) Ta: suppressing CoFeB magnetic dead-layer (ii) Pt: large spin-hall angle (iii) Cu: larger spin-diffusion length. From AR-XPS we observed a sharper composition gradient for Pt-0.5 nm than Pt-1.0 nm in terms of the Se-Pt state. By XAS branching ratio and XMCD sum-rule analyses, we obtained larger spin–orbit coupling (SOC) and spin-polarization (SP) effects on the Pt-0.5, Pt-1.0 nm samples than Cu & Ta insertion. The sharper composition gradient and promoted SOC and SP validate the larger damping-torque efficiency in the Pt-0.5 nm than the Pt-1.0 nm sample. This work manifests interfacial engineering as a powerful avenue for modulating SOT efficiency in spintronic-based applications.
The high-performance atomic layer deposited (ALD) ultrathin (~2 nm) amorphous InZnO (<inline-formula> <tex-math notation="LaTeX">{a} </tex-math></inline-formula>-IZO, indium: Zinc ≈ 6:4) channel ...thin-film transistors (TFTs) with a short channel length (<inline-formula> <tex-math notation="LaTeX">\text{L}_{\mathbf {\textit {ch}}} </tex-math></inline-formula>) of 50 nm were presented. Furthermore, the gate stability was evaluated using temperature-dependent positive-bias stress (PBS) tests for the IZO TFTs up to 3.5 MV/cm. The short channel TFTs exhibited excellent electrical characteristics, with high <inline-formula> <tex-math notation="LaTeX">\text{I}_{\mathbf {\textit {on}}} </tex-math></inline-formula> exceeding <inline-formula> <tex-math notation="LaTeX">360~\mu \text{A} / \mu \text{m} </tex-math></inline-formula> (@<inline-formula> <tex-math notation="LaTeX">\text{V}_{\mathbf {G}} </tex-math></inline-formula> = 2V), and an optimized threshold voltage (<inline-formula> <tex-math notation="LaTeX">\text{V}_{\mathbf {\textit {th}}} </tex-math></inline-formula>) of ~ 0.11 V. In particular, the ultra-low drain-induced barrier lowering (DIBL) performance of 16 mV/V was presented and matched with technology computer aided design (TCAD) estimation. The activation energy of device degradation was extracted to better understand the mechanism. The extracted high field effect channel mobility (<inline-formula> <tex-math notation="LaTeX">\mu _{\mathbf {\textit {FE}}} </tex-math></inline-formula>) of 43.6 cm<inline-formula> <tex-math notation="LaTeX">^{\mathbf {{2}}} </tex-math></inline-formula>/V-s in conjunction with the low <inline-formula> <tex-math notation="LaTeX">\text{V}_{\mathbf {\textit {th}}} </tex-math></inline-formula> shifts of 12.4 mV (@ 3.5 MV/cm; <inline-formula> <tex-math notation="LaTeX">\text{V}_{\mathbf {\textit {th}}} </tex-math></inline-formula> +2V) for 5000s PBS test at <inline-formula> <tex-math notation="LaTeX">25^{\mathbf {o}} </tex-math></inline-formula> C exhibited the excellent performances combining channel mobility and gate stability reported for oxide semiconductor TFT.
Field-free switching (FFS) and spin–orbit torque (SOT)-based neuromorphic characteristics were realized in a W/Pt/Co/NiO/Pt heterostructure with a perpendicular exchange bias (H EB) for ...brain-inspired neuromorphic computing (NC). Experimental results using NiO-based SOT devices guided the development of fully spin-based artificial synapses and sigmoidal neurons for implementation in a three-layer artificial neural network. This system achieved impressive accuracies of 91–96% when applied to the Modified National Institute of Standards and Technology (MNIST) image data set and 78.85–81.25% when applied to Fashion MNIST images, due presumably to the emergence of robust NiO antiferromagnetic (AFM) ordering. The emergence of AFM ordering favored the FFS with an enhanced H EB, which suppressed the memristivity and reduced the recognition accuracy. This indicates a trade-off between the requirements for solid-state memory and those required for brain-inspired NC devices. Nonetheless, our findings revealed opportunities by which the two technologies could be aligned via controllable exchange coupling.
In this article, we have demonstrated the utilization of innovative atomic-layer-deposited (ALD) ultrathin (~1.8 nm) amorphous InSnZnO (<inline-formula> <tex-math notation="LaTeX">\alpha ...</tex-math></inline-formula>-ITZO) channel material in the development of a back-end-of-line (BEOL) compatible thin film transistor (TFT). Through the optimization of the indium/tin/zinc (In/Sn/Zn) ratio, the bottom gate (BG) TFT with In0.83Sn0.11Zn0.06O channel and the channel length (<inline-formula> <tex-math notation="LaTeX">{L}_{\text {ch}} </tex-math></inline-formula>) of 40 nm demonstrates remarkable performances, including positive threshold voltage (<inline-formula> <tex-math notation="LaTeX">{V}_{\text {th}} </tex-math></inline-formula>) of 0.38 V, excellent subthreshold swing (SS) value of 66.4 mV/dec, high field-effect mobility (<inline-formula> <tex-math notation="LaTeX">\mu _{\text {FE}} </tex-math></inline-formula>) of 48 cm2/V-s, maximum ON-state current density (<inline-formula> <tex-math notation="LaTeX">{I}_{\text {ON}} </tex-math></inline-formula>) of <inline-formula> <tex-math notation="LaTeX">686~\mu \text{A}/\mu \text{m} </tex-math></inline-formula> at <inline-formula> <tex-math notation="LaTeX">{V}_{\text {DS}} </tex-math></inline-formula> = 2 V (@<inline-formula> <tex-math notation="LaTeX">{V}_{G} </tex-math></inline-formula> = 4 V), and extremely low drain-induced barrier lowering (DIBL) performance of 22 mV/V. Furthermore, the excellent stabilities of the <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula>-ITZO TFT were shown by negative bias stress (NBS) and positive bias stress (PBS) under <inline-formula> <tex-math notation="LaTeX">{V}_{G} </tex-math></inline-formula> of (<inline-formula> <tex-math notation="LaTeX">{V}_{\text {th}}~\pm </tex-math></inline-formula> 3 V), and <inline-formula> <tex-math notation="LaTeX">{V}_{\text {th}} </tex-math></inline-formula> shift (<inline-formula> <tex-math notation="LaTeX">\Delta {V}_{\text {th}} </tex-math></inline-formula>) of −40 and 60 mV (<inline-formula> <tex-math notation="LaTeX">{L}_{\text {ch}} </tex-math></inline-formula> = 700 nm) after 3600 s was exhibited. We also simulated the current gain cutoff frequency (<inline-formula> <tex-math notation="LaTeX">{f}_{T} </tex-math></inline-formula>) by technology computer-aided design (TCAD) simulation to further investigate the potential of radio frequency (RF) applications. These results establish a competitive standard for TFTs based on quaternary ultrathin (<inline-formula> <tex-math notation="LaTeX">{T}_{\text {ch}} < 5 </tex-math></inline-formula> nm) amorphous oxide semiconductors (AOSs).
In this study, we investigated the impact of inserting an interfacial layer (IL) between the InZnO channel and ZrO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> ...</inline-formula>/HfO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> superlattice (SL) ferroelectric (FE) gate-stack on the performance and stability of highly scaled FE thin-film transistors (FeTFTs). FeTFTs with various channel lengths (50-750 nm) were characterized to reveal the impact of two IL (i.e., TiO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> and Al<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula>O<inline-formula> <tex-math notation="LaTeX">_{\text{3}}\text{)}</tex-math> </inline-formula> on device characteristics. All the memory window (MW) contours of FeTFTs with a pulsewidth of 1 ms-100 ns and an amplitude of 2.5-5 V have been investigated. The FeTFT with TiO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> IL demonstrated impressive stability in MW (<inline-formula> <tex-math notation="LaTeX">\bm{\Delta} </tex-math> </inline-formula>MW/MW<inline-formula> <tex-math notation="LaTeX">_{\text{1}\text{st cy}\text{cle}}</tex-math> </inline-formula> <inline-formula> <tex-math notation="LaTeX">\bm{\le} </tex-math> </inline-formula> 3.6%) up to 10<inline-formula> <tex-math notation="LaTeX">^{\text{8}}</tex-math> </inline-formula> cycles for a program/erase voltage of <inline-formula> <tex-math notation="LaTeX">\bm{\pm}</tex-math> </inline-formula>3 V and pulsewidth of 1 <inline-formula> <tex-math notation="LaTeX">\bm{\mu} </tex-math> </inline-formula>s. It was suggested that the FeTFT with a higher dielectric constant <inline-formula> <tex-math notation="LaTeX">\text{(}\textit{k}\text{)}</tex-math> </inline-formula> TiO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> IL may reduce the electrical field and depolarization field at the interface between the channel and gate dielectric, as well as improve interfacial quality, thereby enhancing the reliability of FeTFTs.
Electrical determination of magnetization switching is essential in the development of spintronics devices. However, for in-plane magnetic anisotropic systems, electrical readout of magnetization is ...challenging on simple Hall bar devices. Here, we propose a simple method based on DC measurement to probe magnetization switching on the spin-orbit Hall bar devices. The observed resistance-field relation is highly coincidental with the magnetic hysteresis loop measured at sheet films. Our result provides an effective method to evaluate the magnetization switching of the in-plane anisotropic systems on the Hall bar devices.
In this study, we reported the employment of atomic-layer-deposited (ALD) ultrathin (~1.8 nm) amorphous InSnZnO (a-ITZO) as an innovative channel material to develop the back-end-of-line (BEOL) ...compatible thin film transistor (TFT) for monolithic 3D integration for the first time. By carefully adjusting the In/Sn/Zn ratio through ALD cycles, the bottom gate (BG) TFT with ALD In0.83Sn 0.11 Zn 0.06 O channel and channel length (L ch ) of 40 nm demonstrates remarkably optimized performance characteristics, including positive threshold voltage (V th ) of 0.38 V, excellent subthreshold swings (SS) value of 66.4 mV/dec, and high electron mobility (μEE) of 48 cm2/V-s. Moreover, the maximum on-state current density (ION) of 686 μA/μm at VDS=2V and impressively low drain-induced barrier lowering (DIBL) performance of 22 mV/V were exhibited. These results are among the most competitive values reported for TFTs based on quaternary ultrathin (Tch < 5 nm) amorphous oxide semiconductors. Furthermore, the TFT demonstrates highly stable device characteristics, as evidenced by threshold voltage shift (ΔV th ) of -40 mV and 60 mV (L ch = 700 nm) after 3600 seconds of negative gate bias stress (NBS) and positive gate bias stress (PBS) with |VG-V th | of 3 V.
To evaluate the diagnostic efficacy of gastric juice-based genotypic methods for Helicobacter pylori detection and antibiotic resistance testing.
We used electronic databases including Medline, ...Embase, Web of Science and the Cochrane Central Register of Controlled Trial for literature survey using keywords such as "gastric juice", "Helicobacter pylori" and their synonyms. The quality of the studies was assessed using QUADAS-2. Summary performance measures (sensitivity, specificity, positive predictive values, negative predictive values, diagnostic odds ratio, and area under the summary receiver operating characteristic curve) and HSROC curves were produced. In addition, fagan plots were applied to illustrate the relationship among the prior test probability, PLR/NLR, and posterior test probability.
Our study cohort comprised eight studies with 1235 participants (617 participants of H. pylori infection and 618 participants of non-H. pylori infection). Pooled sensitivity and specificity with a corresponding 95% confidence interval (CI) of gastric juice-based genotypic methods reflected values of 94% (95%CI, 86% - 98%) and 98% (95%CI, 85% - 100%), respectively. The global sensitivity and specificity of clarithromycin resistance were 92% (95%CI, 85% - 96%) and 90% (95%CI, 80% - 95%), respectively.
Gastric juice-based genotypic methods can be used for diagnostic prediction of H. pylori infection as well as clarithromycin resistance testing.
A major challenge to realizing a highly energy-efficient magneto-electric spin-orbit (MESO) logic device is the small signal response of ferromagnetic spin state readout by inverse spin Hall (ISH) ...effect, which makes it difficult to meet the practical device design. Here, we present a scalable T-shape W/CoFeB ISH device with tunable spin-to-charge conversion effects. The ISH signal appeared to increase with reducing the W channel width, achieving 40mΩ with a channel width down to 95nm. Tuning the sputtering dc power can further adjust the ISH signal. Our finding provides a pathway to improve the ISH signal in patterned devices that is beneficial for developing next-generation spintronic logic devices.
