bluuebunny/crossref_metadata_2025 huggingface dataset:
Leadership in healthcare: a bibliometric analysis of 100 most influential publications
Authors: Bhulani Nizar , Miao Timothy L , Norbash Alexander , Castillo Mauricio , Khosa Faisal
Published: September 2020

Aim

We analysed the 100 most influential articles on leadership in healthcare via a bibliometric analysis to better understand categories and topics in leadership science and their relationship to healthcare. Leadership in healthcare is ever evolving and needs to be robust like any another profession.

Methods

A bibliometric analysis was performed. Articles were ranked by citation counts and three independent reviewers screened the abstracts for inclusion. Common themes were categorised.

Results

Citations for articles ranged from 53 to 487 and were published across 50 journals. Articles focused primarily on three leadership subjects: team building, quality improvement and healthcare delivery. Of healthcare provider groups, articles were directed to or concerning primarily: nursing, academic medicine and critical care medicine.

Conclusions

We identified gaps in healthcare leadership development literature. There is an opportunity to effectively identify areas of interest and demand for organised leadership education and training.
Multicentre retrospective cohort study assessing the incidence of serious infections in patients with lupus nephritis, compared with non-renal systemic lupus erythematosus
Authors: Yates Drew Joseph , Mon Saw Yu , Oh Yumi , Okano Satomi , Manickam Valli , Soden Muriel , Kubler Paul , Ranganathan Dwarakanathan
Published: September 2020

Objectives

The incidence of serious infections is poorly defined in patients with lupus nephritis (LN). It is also unclear if LN influences risk of serious infections in a longitudinal analysis. The aim of this study was to determine the incidence of serious infections in patients with SLE and LN, compared with patients with SLE without LN.

Methods

A multicentre retrospective cohort study was conducted. Patients with LN identified at two tertiary centres were matched where possible with age and gender-matched patients with SLE without LN.

Any infection requiring inpatient admission, occurring in the 6 months following index clinical visit, was considered serious. Cox regression was employed to investigate the association between risk of serious infection and LN status, and other relevant covariates.

Results

A total of 173 patients were included within the analysis (n=87 LN, n=86 SLE only). A total of 9.2% (n=8) of patients with LN experienced at least one serious infection within the study period, compared with 5.8% (n=5) of patients without LN, equivalent to 19.5 and 12.0 infections per 100 patient-years with and without LN, respectively. Univariable and multivariable analyses found no significant increased risk of serious infection in patients with LN versus controls (HR 1.61; 95% CI 0.53 to 4.92 and adjusted HR (aHR) 0.91; 95% CI 0.27 to 3.06, respectively). Increased prednisone dose and modified SLE comorbidity index were strongly associated with serious infection (aHR (per 5 mg) 1.21; 95% CI 1.07 to 1.37; p=0.003 and aHR 1.13; 95% CI 1.02 to 1.25; p=0.018, respectively).

Conclusions

In this cohort, adjusting for cofactors, the presence of LN alone does not appear to increase the risk of serious infections compared with patients with SLE without LN. However, increased prednisone dose at baseline visit and increasing comorbidity were independently associated with the incidence of serious infection.
Cutaneous vasculitis in SLE
Authors: Kallas Romy , Goldman Daniel , Petri Michelle A
Published: September 2020

Objectives

We determined the temporal association between clinical and serological disease manifestations and development of cutaneous small vessel vasculitis in a large prospective multiethnic cohort.

Methods

Patients with SLE diagnosed according to the Systemic Lupus International Collaborating Clinics (SLICC) classification criteria or the revised classification criteria as defined by the American College of Rheumatology (ACR) were enrolled in the Hopkins Lupus Cohort. Cutaneous small vessel vasculitis was determined as a component of the Systemic Lupus Erythematosus Disease Activity Index. SLE-associated cutaneous small vessel vasculitis lesions were reported clinically. They presented as punctate lesions, palpable purpura, tender erythematous plaques or macules with or without necrosis. No histopathological diagnosis was pursued to confirm the diagnosis of vasculitis or to differentiate it from other causes of digital lesions in patients with SLE. Disease manifestations that preceded the first occurrence of cutaneous small vessel vasculitis lesions were analysed using Kaplan-Meier. Cox regression analysis was used to assess the relationship between baseline clinical and immunological manifestations and the development of cutaneous small vessel vasculitis. We adjusted for gender, race and age at SLE diagnosis.

Results

A total of 2580 patients were studied: 52.4% were Caucasian and 39.4% were African-American. The mean age of the cohort was 45.5±14.5 years. The mean years of cohort follow-up was 7.9±7.6. Cutaneous small vessel vasculitis was observed in 449 (17.3%). The mean time to cutaneous vasculitis after SLE diagnosis was 4.78 years (95% CI 3.96 to 5.60). At least 159 (35%) patients had recurrences of cutaneous vasculitis lesions. Discoid rash, Raynaud’s phenomenon, myositis, anaemia, Coombs’ positivity, leucopenia, anti-Smith and anti-RNP (Ribonucleoprotein) were significantly associated with the development of cutaneous vasculitis. The SLICC/ACR Damage Index score was higher in patients with cutaneous vasculitis compared with those without cutaneous vasculitis.

Conclusions

Cutaneous vasculitis is frequent (17.3%) and often recurrent (35%). African-Americans are at higher risk of developing cutaneous small vessel vasculitis than Caucasians. Clinical presentations such as myositis and haematological manifestations are predictors of cutaneous vasculitis development. The presence of cutaneous vasculitis is associated with increased organ damage.
Accuracy of telephone triage in primary care patients with chest discomfort: a cross-sectional study
Authors: Wouters Loes TCM , Rutten Frans H , Erkelens Daphne CA , De Groot Esther , Damoiseaux Roger AMJ , Zwart Dorien LM
Published: September 2020

Objective

To assess the accuracy of semi-automatic assisted telephone triage in patients with acute chest discomfort against the diagnosis of acute coronary syndrome (ACS) or other life-threatening events (LTEs).

Methods

A cross-sectional study was performed of telephone conversations with 2023 patients with acute chest discomfort (pain, pressure, tightness or discomfort) who called out-of-hours services for primary care (OHS-PC) between 2014 and 2016. Sensitivity, specificity, positive and negative predicted values were calculated for a high urgency (patient seen within one hour) against the diagnoses of ACS and other LTEs. Diagnoses were retrieved from the patients' medical records in general practice, including hospital specialists' discharge letters.

Results

Of 2023 patients who called because of chest discomfort, 227 (11.2%) had an ACS (men 14.9%, women 8.2%) and 58 (2.9%) had another LTE (men 3.6%, women 2.3%). The sensitivity and specificity of a high Netherlands Triage System (NTS) urgency allocation against ACS/other LTEs were 0.73 (95% CI 0.68 to 0.78) and 0.43 (95% CI 0.40 to 0.45), respectively. In 13.2% of the calls the triage nurse overruled the NTS urgency, mostly by upscaling (11.0%). The sensitivity and specificity of the final urgency allocation were 0.86 (95% CI 0.81 to 0.90) and 0.34 (95% CI 0.32 to 0.37). The positive and negative predictive values of the final urgency were 0.18 (95% CI 0.17 to 0.19) and 0.94 (95% CI 0.92 to 0.95), respectively.

Conclusions

The semi-automatic triage NTS tool underestimated the urgency in 27% of patients with ACS/other LTEs. Overruling by triage nurses improved safety, but still 14% of men and women with ACS/other LTEs received too low urgency, while efficiency remained poor.

Trial registration number

NTR7331.
Traumatic pericarditis in a dairy doe
Authors: Smith Joseph , Breuer Ryan , Kreuder Amanda , Merkatoris Paul , Yaeger Michael
Published: September 2020

A two‐year‐old pregnant Toggenberg doe presented for recumbency, anorexia and hypothermia. The owner noted that the doe had been experiencing anorexia for approximately 1 month's duration. Initial diagnostics revealed a leucocytosis with a left shift, ketonaemia, as well as decreased serum potassium and bicarbonate concentrations. Thoracic ultrasound identified moderate pericardial perfusion. The doe expired during an emergency caesarean section. Necropsy revealed a 2.5‐cm‐long hypodermic needle fragment that had migrated from the reticulum to the pericardial cavity and ultimately to the omental fat. While not commonly described in small ruminants, practitioners should be aware of the potential for traumatic pericarditis in goats and, as such, should consider hardware disease a differential for goats with pericardial effusion.
Feasibility and effects on the gut microbiota of a 12-week high-intensity interval training plus lifestyle education intervention on inactive adults with celiac disease
Authors: Warbeck Cassandra , Dowd A. Justine , Kronlund Liam , Parmar Candice , Daun Julia T. , Wytsma-Fisher Kathryn , Millet Guillaume Y. , Schick Alana , Reimer Raylene A. , Fung Tak , Culos-Reed S. Nicole
Published: September 2020

This study assessed the feasibility and benefits of high-intensity interval training (HIIT) plus lifestyle education among inactive adults with celiac disease. Forty-one participants were randomized to receive the intervention (HIIT plus lifestyle education; HIIT+) for 12 weeks or waitlist control (WLC). Testing was completed at baseline, immediately post-intervention, and 3 months post-intervention. Generalized estimating equations were used to assess changes in the outcome variables over time between the groups. Mean percent of age-predicted maximum heart rate was 97.9% and average rating of perceived exertion was 6.33 (out of 10) during HIIT intervals. Following the intervention, the HIIT+ showed enrichment in relative abundance of Parabacteroides and Defluviitaleaceae_UCG_011 while WLC showed enrichment in relative abundance of Roseburia intestinalis, Klebsiella, and Adlercreutzia. A unique set of taxa were differentially abundant between the groups at 3 months post-intervention. HIIT+ participants experienced a reduction in resting heart rate (−6.6 bpm) immediately post-intervention compared with WLC. Further research is needed to establish an optimal HIIT protocol that may improve maximal oxygen uptake and metabolic syndrome biomarkers. Findings from this pilot study provide preliminary evidence that an HIIT intervention is feasible for inactive adults with celiac disease and leads to favourable changes in resting heart rate alongside potentially beneficial shifts in gut microbiota. Trial registration number: ClinicalTrials.gov number NCT03520244.

Novelty: HIIT leads to potentially beneficial changes in the gut microbiota of adults with celiac disease. An HIIT exercise intervention is feasible and well tolerated for patients with celiac disease.
Defiducialization: providing experimental measurements for accurate fixed-order predictions
Authors: Glazov A.
Published: September 2020

An experimental procedure is proposed to perform measurements of differential cross sections for vector boson production which can be compared to fixed-order QCD predictions with improved accuracy. The procedure relies on applying theoretical acceptance corrections computed as a function of the transverse momentum of the W/Z boson, $$p_T$$

p
T

, to the experimental measurement, rather than comparing data directly against fiducial fixed-order predictions. It is demonstrated that, contrary to standard fiducial computations, these acceptance factors vary little at low $$p_T$$

p
T

, so they can be reliably computed using fixed-order perturbation theory. An example analysis is performed using the ATLAS measurement of the Z-boson production cross section at center-of-mass energy of 8 TeV. The resulting full phase space measurement of the cross section differential in the boson rapidity is compared to theoretical predictions computed with next-to-next-to leading-order accuracy in QCD. Further extensions of the approach which include different types of measurements and improved theoretical predictions are discussed.
Greybody factor and power spectra of the Hawking radiation in the 4D Einstein–Gauss–Bonnet de-Sitter gravity
Authors: Zhang Cheng-Yong , Li Peng-Cheng , Guo Minyong
Published: September 2020

A novel 4D Einstein–Gauss–Bonnet gravity was recently formulated by Glavan and Lin [Phys. Rev. Lett. 124, 081301 (2020)]. Although this theory may run into trouble at the level of action or equations of motion, the spherically symmetric black hole solution, which can be successfully reproduced in those consistent theories of 4D EGB gravity, is still meaningful and worthy of study. In this paper, we investigate Hawking radiation in the spacetime containing such a de Sitter black hole. Both the greybody factor and the power spectra of the Hawking radiation of the massless scalar are studied numerically for the full range of various parameters, including the GB coupling constant $$\alpha $$
α
, the cosmological constant $$\Lambda $$
Λ
and the coupling constant related to the scalar filed $$\xi $$
ξ
. In particular, we find a negative $$\alpha $$
α
leads to a larger greybody factor than that of a $$\alpha \ge 0$$

α
≥
0

. While, for the power spectra of the Hawking radiation the situation is quite the opposite. The reason is that the temperature of the black hole would be very high when $$\alpha <0$$

α
<
0

. Actually, we observe that the temperature would be arbitrarily high when $$\alpha $$
α
approaches to the lower bound.
Slowly rotating topological neutron stars: universal relations and epicyclic frequencies
Authors: Danchev Victor I. , Doneva Daniela D. , Yazadjiev Stoytcho S.
Published: September 2020

In the modern era of abundant X-ray detections and the increasing momentum of gravitational waves astronomy, tests of general relativity in strong field regime become increasingly feasible and their importance for probing gravity cannot be understated. To this end, we study the characteristics of slowly rotating topological neutron stars in the tensor-multi-scalar theories of gravity following the static study of this new type of compact objects by two of the authors. We explore the moment of inertia and verify that universal relations known from general relativity hold for this new class of compact objects. Furthermore, we study the properties of their innermost stable circular orbits and the epicyclic frequencies due to the latter’s hinted link to observational quantities such as quasi-periodic X-ray spectrum features.
On anomalies in effective models with nonlinear symmetry realization
Authors: Arbuzov Andrej , Latosh Boris
Published: September 2020

Anomalous features of models with nonlinear symmetry realization are addressed. It is shown that such models can have anomalous amplitudes breaking of its original symmetry realization. An illustrative example of a simple models with a nonlinear conformal symmetry realization is given. It is argued that the effective action obtained via nonlinear symmetry realization should be used to obtain an anomaly-induced action which is to drive the low-energy dynamics.
Hyperbolic tunnel-number-one knots with Seifert-fibered Dehn surgeries
Authors: Kang Sungmo
Published: September 2020

Suppose [Formula: see text] and [Formula: see text] are disjoint simple closed curves in the boundary of a genus two handlebody [Formula: see text] such that [Formula: see text] (i.e. a 2-handle addition along [Formula: see text]) embeds in [Formula: see text] as the exterior of a hyperbolic knot [Formula: see text] (thus, [Formula: see text] is a tunnel-number-one knot), and [Formula: see text] is Seifert in [Formula: see text] (i.e. a 2-handle addition [Formula: see text] is a Seifert-fibered space) and not the meridian of [Formula: see text]. Then for a slope [Formula: see text] of [Formula: see text] represented by [Formula: see text], [Formula: see text]-Dehn surgery [Formula: see text] is a Seifert-fibered space. Such a construction of Seifert-fibered Dehn surgeries generalizes that of Seifert-fibered Dehn surgeries arising from primtive/Seifert positions of a knot, which was introduced in [J. Dean, Small Seifert-fibered Dehn surgery on hyperbolic knots, Algebr. Geom. Topol. 3 (2003) 435–472.].

In this paper, we show that there exists a meridional curve [Formula: see text] of [Formula: see text] (or [Formula: see text]) in [Formula: see text] such that [Formula: see text] intersects [Formula: see text] transversely in exactly one point. It follows that such a construction of a Seifert-fibered Dehn surgery [Formula: see text] can arise from a primitive/Seifert position of [Formula: see text] with [Formula: see text] its surface-slope. This result supports partially the two conjectures: (1) any Seifert-fibered surgery on a hyperbolic knot in [Formula: see text] is integral, and (2) any Seifert-fibered surgery on a hyperbolic tunnel-number-one knot arises from a primitive/Seifert position whose surface slope corresponds to the surgery slope.
Co-maximal Graph, its Planarity and Domination Number
Authors: SINHA DEEPA , RAO ANITA KUMARI
Published: September 2020

Let R be a finite commutative ring with identity. The co-maximal graph Γ(R) is a graph with vertices as elements of R, where two distinct vertices a and b are adjacent if and only if Ra + Rb = R. Also, Γ2(R) is the subgraph of Γ(R) induced by non-unit elements and [Formula: see text] where J(R) is Jacobson radical. In this paper, we characterize the rings for which the graphs Γ(R) and L(Γ(R)) are planar. Also, we characterize rings for which [Formula: see text], Γ(R) and L(Γ(R)) are outerplanar along with some domination parameters on co-maximal graph.
Reliability-Based Robust Design Optimization in Consideration of Manufacturing Tolerance by Multi-Objective Evolutionary Optimization with Repair Algorithm
Authors: Li Gang , Liu Ye , Zhao Gang , Zeng Yan
Published: September 2020

There are inherently various uncertainties in practical engineering, and reliability-based design optimization (RBDO) and robust design optimization (RDO) are two well-established methodologies when considering the uncertainties. Naturally, reliability-based robust design optimization (RBRDO) is a methodology developed recently by combining RBDO and RDO, in which the tolerances of random design variables are always assumed as constants. However, the tolerance of random design variables is a key factor for the objective robustness and manufacturing cost, and the tolerance allocation is the core problem in mechanical manufacturing. Inspired by the cost–tolerance relationship in mechanical manufacturing, this paper presents an integrated framework to simultaneously find the optimal design variable and the corresponding tolerance in the multi-objective RBRDO, with the trade-off between objective robustness and manufacturing cost. The failure mechanism of the constraint handling strategy of the constrained reference vector-guided evolutionary algorithm (C-RVEA) is discussed to solve the multi-objective optimization formulation. Then the robust repair operator and reliability-based repair operator are proposed to transform unfeasible solutions to the feasible ones under reliability constraints. Numerical results reveal that the proposed repair algorithm is effective. By solving the integrated multi-objective optimization problem, the Pareto front with the compromised solutions between the objective robustness and manufacturing cost could be obtained, from which decision makers can select the satisfying solution conveniently according to the preferred requirements.
Connected monophonic domination in graphs
Authors: Sadiquali A. , Arul Paul Sudhahar P. , Lakshmana Gomathi Nayagam V.
Published: September 2020

A collection of vertices in different connected graphs embraces a wholesome shift into a new collection with the properties of the couplets monophonic and dominating sets. The new collection of vertices and associated invariant with the new behavior of connected graphs are called as connected monophonic dominating set (cmd-set) and connected monophonic domination number (cmd-number), respectively. Certain initial results are studied. The cmd-number is characterized with some conditions. Some realization problems related to a connected graph by imposing conditions on the vertex count are also presented.
GPUOPT
Authors: Bashir Janibul , Sarangi Smruti R.
Published: September 2020

On-chip photonics is a disruptive technology, and such NoCs are superior to traditional electrical NoCs in terms of latency, power, and bandwidth. Hence, researchers have proposed a wide variety of optical networks for multicore processors. The high bandwidth and low latency features of photonic NoCs have led to the overall improvement in the system performance. However, there are very few proposals that discuss the usage of optical interconnects in Graphics Processor Units (GPUs). GPUs can also substantially gain from such novel technologies, because they need to provide significant computational throughput without further stressing their power budgets.

The main shortcoming of optical networks is their high static power usage, because the lasers are turned on all the time by default, even when there is no traffic inside the chip, and thus sophisticated laser modulation schemes are required. Such modulation schemes base their decisions on an accurate prediction of network traffic in the future. In this article, we propose an energy-efficient and scalable optical interconnect for modern GPUs called
GPUOPT
that smartly creates an overlay network by dividing the symmetric multiprocessors (SMs) into clusters. It furthermore has separate sub-networks for coherence and non-coherence traffic. To further increase the throughput, we connect the off-chip memory with optical links as well.

Subsequently, we show that traditional laser modulation schemes (for reducing static power consumption) that were designed for multicore processors are not that effective for GPUs. Hence, there was a need to create a bespoke scheme for predicting the laser power usage in GPUs.

Using this set of techniques, we were able to improve the performance of a modern GPU by 45% as compared to a state-of-the-art electrical NoC. Moreover, as compared to competing optical NoCs for GPUs, our scheme reduces the laser power consumption by 67%, resulting in a net 65% reduction in
ED
2
for a suite of Rodinia benchmarks.
The Evolutionary and Historical Foundation of the Modern Horse: Lessons from Ancient Genomics
Authors: Orlando Ludovic
Published: September 2020

The domestication of the horse some 5,500 years ago followed those of dogs, sheep, goats, cattle, and pigs by ∼2,500–10,000 years. By providing fast transportation and transforming warfare, the horse had an impact on human history with no equivalent in the animal kingdom. Even though the equine sport industry has considerable economic value today, the evolutionary history underlying the emergence of the modern domestic horse remains contentious. In the last decade, novel sequencing technologies have revolutionized our capacity to sequence the complete genome of organisms, including from archaeological remains. Applied to horses, these technologies have provided unprecedented levels of information and have considerably changed models of horse domestication. This review illustrates how ancient DNA, especially ancient genomes, has inspired researchers to rethink the process by which horses were first domesticated and then diversified into a variety of breeds showing a range of traits that are useful to humans.
The Effects of Dual Atmosphere Exposure Duration and Temperature on the Growth of Iron Oxide on Ferritic Stainless Steels
Authors: Reisert Michael , Aphale Ashish N , Singh Prabhakar
Published: September 2020

In this study, the oxidation behavior of two ferritic steels with different amounts of chromium is examined under dual atmosphere exposure conditions. Experiments with varying time and temperature were carried out to understand the effects of these variables and difference in chromium concentration on severity and morphology of oxidation products. Higher amounts of alloyed chromium in the steel leads to better passivation against iron oxidation. With increased exposure time, however, the passivating scale breaks down leading to iron oxide overgrowth. This phenomenon appears more pronounced at lower temperatures and complete passivation of both steels was observed at the higher temperature (700°C) after 100 h of exposure. A hypothesis with regards to the presence of hydrogen during exposure is presented along with discussion on observed oxidation behavior.
(Invited) Benefits of Zr Addition on Hot Corrosion and Isothermal Oxidation Resistance of Single-Phase (Ni,Pt) Al Coatings
Authors: Jiang Chengyang , Bao Zebin , Zhu Shenglong , Wang Fuhui
Published: September 2020

A Zr-doped single-phase (Ni,Pt) Al coating was prepared on a Ni-based single crystal superalloy through electroplating Pt-Zr composite layer and subsequent gaseous aluminisation treatments. Hot corrosion and isothermal oxidation tests of NiAl, (Ni,Pt) Al and Zr-doped (Ni,Pt) Al coatings were conducted in static air. The results indicated that Zr-doped coatings showed superior hot corrosion resistance to both conventional aluminide and (Ni,Pt) Al coatings, the enhanced performance was mainly attributed to the advantageous effects of Zr that interacted with S and Cl. The mechanism and role of Zr played in the corrosion test are discussed. Meanwhile, Zr-doped (Ni,Pt) Al coating demonstrated lower oxidation rate constant, which was mainly attributed to the favoring effects of Zr preferring to segregate at grain boundaries of oxide scale. Besides, the addition of zirconium effectively delayed the oxide phase transformation from θ-Al2O3 to α-Al2O3 in early oxidation stage and the coating degradation from β-NiAl to γ'-Ni3Al in stable oxidation stage.
(Invited) Axial Silicon-Germanium Nanowires: Properties and Device Applications
Authors: Tsybeskov Leonid , Kamins Theodore I , Wu Xiaohua , Lockwood David J.
Published: September 2020

Dense nanowire films can be considered as quasi-porous structures with a high surface-to-volume ratio. From this perspective, structural, optical and electrical properties of axial Si-Ge nanowire heterojunctions produced by the vapor-liquid-solid growth method using Au nanoclusters as catalysts are analyzed. The lattice mismatch induced strain is partially relieved due to spontaneous SiGe intermixing at the heterointerface and lateral expansion of the Ge segment of the nanowire. The mismatch in Ge and Si coefficients of thermal expansion and low thermal conductivity of Si-Ge nanowire heterojunctions are found to be responsible for the thermally induced stress detected under intense laser radiation in photoluminescence and Raman scattering measurements. In electrical measurements, the observed non-linear current-voltage characteristics, strong flicker noise, and damped current oscillations with frequencies of 20-30 MHz are explained using a proposed Si-Ge nanowire heterojunction energy band diagram that includes energy states associated with structural imperfections at the nanowire surface.
Luminescent Porous Silicon Filled with Nanoscopic Magnetic Structures – Assessment of the Optical and Magnetic Properties
Authors: Granitzer Petra , Rumpf Klemens , Reissner Michael , Michor Herwig
Published: September 2020

Luminescent porous silicon which is denoted as microporous silicon (LPSi) offers a structure size of a few nanometers. The pores are arranged in a branched network-like morphology. These structures are filled with magnetic metals resulting in a composite system with specific optical and magnetic properties. In this work Ni and Co, respectively are used. The luminescence is observed in the red-orange region due to the small structure size. The photoluminescence spectra of initial LPSi offer a peak around 620 nm, which is blue-shifted after Ni-filling with increasing deposition time and the intensity of the luminescence is increased. In the case of Co deposition the spectrum is adequate but with increasing metal filling the luminescence intensity decreases. Magnetic field dependent measurements performed for easy and hard axis magnetization show a high magnetic anisotropy between these two magnetization directions, even more pronounced in the case of Co. The magnetic response of the samples is related to the interconnected pores and differs significantly to mesoporous silicon filled with magnetic nanostructures.
(Invited) Development of Nanoporous Structures and Oscillatory Behavior During Anodization of n-InP in Alkaline Electrolytes
Authors: Buckley D. Noel , Quill Nathan , O'Dwyer Colm , Melly Tom , Harvey Elizabeth , Lynch Robert P.
Published: September 2020

In the early stages of anodization of n-InP in KOH, isolated nanoporous domains form and eventually merge into a continuous layer. SEM and TEM cross-sections show clear evidence that these have the shape of truncated tetrahedrons and result from preferential pore progagation along the <111>A directions. We propose a three-step model of electrochemical nanopore formation that explains how crystallographically oriented etching can occur even though the rate-determining process occurs only at pore tips. The rate-determining Step 1 is the generation of holes at pore tips. If Step 2 (hole diffusion) is faster than Step 3 (electrochemical reaction) then etching can occur at preferred crystallographic sites, such as phosphorus dangling bonds, leading to pore propagation in preferential directions. Well-defined oscillations are observed under certain conditions when n-InP is anodized in either KOH or (NH4)2S. The oscillations in (NH4)2S, have a symmetric profile and the charge per cycle remains constant over a wide range of conditions: we propose a mechanism based on cyclical changes in the morphology of the InP surface beneath an In2S3 film. The exact mechanism of the oscillatory behavior in KOH is still unclear.
Fabrication of Graphene-Inserted Tunneling Device (GiTD) for Emerging Spin Devices
Authors: Cherian Hebin Roy , Birge Norman , Pollanen Johannes , Ahn Ethan C
Published: September 2020

Spintronic nanostructures such as magnetic tunnel junctions possess great potential for advancing a future computing paradigm requiring high speed and low power consumption. One great challenge limiting their widespread application is the conductivity mismatch between the ferromagnet and the channel material, resulting in low spin injection efficiency. The possible use of graphene as an atomically-thin tunnel barrier has been widely discussed because it could be readily interfaced with the ferromagnet to mitigate the conductivity mismatch problem. However, it still remains relatively unexplored to quantitatively understand how graphene will impact the spin polarization of tunneling currents. Here we present the experimental process to design and fabricate a graphene-inserted tunneling device, which will serve as the useful platform to study the fundamentals required for developing emerging spin devices. Further follow-up studies such as superconducting tunneling spectroscopy can be applied to the device structure developed in this work.
Highly Oriented Growth of AlxSc1-X N Ferroelectric Film on W Bottom Electrodes
Authors: Tsai SungLin , Hoshii Takuya , Wakabayashi Hitoshi , Tsutsui Kazuo , Kakushima Kuniyuki
Published: September 2020

Electrical characteristics and physical analyses of sputter deposited 50-nm-thick ferroelectric AlxSc1-xN films on W bottom electrodes are examined. A highly c-axis oriented growth of the Al0.8Sc0.2N film with ferroelectric capacitance-voltage characteristics is confirmed. The Al0.8Sc0.2N films showed better oriented growth than sputter deposited AlN films or Al0.8Sc0.2N/AlN stacked films. The results indicate that Al0.8Sc0.2N films directly deposited on W electrodes have the advantage to obtain the c-axis oriented Al0.8Sc0.2N films.
Improvement of Ferroelectricity and Fatigue Property of Thicker HfxZr1−XO2/ZrO2 Bi-layer
Authors: Onaya Takashi , Nabatame Toshihide , Inoue Mari , Jung Yong Chan , Hernandez-Arriaga Heber , Mohan Jaidah , Kim Harrison Sejoon , Sawamoto Naomi , Nagata Takahiro , Kim Jiyoung , Ogura Atsushi
Published: September 2020

We studied the ferroelectricity of the metal–ferroelectric–metal capacitors with a HfxZr1−xO2 (10 nm) (HZO) single layer, and HfxZr1−xO2 (10 nm)/ZrO2 (10 nm) (HZO/ZO) and HfxZr1−xO2 (10 nm)/HfO2 (10 nm) (HZO/HO) bi-layers. HZO/ZO and HZO exhibited high remanent polarization (2P
r
= P
r

+
− P
r
−) of 13 and 12 µC/cm2, respectively, compared to HZO/HO (0.5 µC/cm2) after 104 wake-up cycles. This is due to the difference of the amount of ferroelectric orthorhombic phase. We found that the breakdown voltage of HZO/ZO was approximately 1.5 times higher than that of HZO while maintaining a high 2P
r value. Moreover, HZO/ZO kept 1.4 times higher 2P
r value than HZO after 106 switching cycles because the phase transformation from anti-ferroelectric to ferroelectric phase of ZrO2 layer in HZO/ZO could occur during field cycling. Therefore, HZO/ZO bi-layer using the combination of HZO and ZrO2 layers is one of the promising ferroelectric layer for future ferroelectric devices application.
The Metal Gate Cut Process Development
Authors: Ji Shi-liang , Han Qiu-Hua , Zhang Hai-Yang
Published: September 2020

The technology of FinFET has led to the continuity of device scaling and enabled the prolongation of Moore’s Law towards the 7nm and beyond nodes. The metal gate cut(MGC) will be widely adopted since it can provide better SiP/SiGe growth environment, improve yield, and enhance electrical performance. However, this approach requires more complex process engineering at 3D structure. Both perfect physical structure and good electronic performance are challenging for metal gate cut last process. This paper will introduce metal gate cut process to form separation transistor. This definitely requires large CD shrinkage etch process to avoid lithography limitation and channel while meeting all the physical targets.
Near-Room-Temperature Soft Plasma Pulsed Deposition of SiCxNy from 1,3,5-tri(isopropyl)cyclotrisilazane
Authors: Goff Jonathan , Brick Chad Michael , Kaloyeros Alain , Arkles Barry
Published: September 2020

Results are presented from an exploratory study of near-room-temperature pulsed deposition of SiCxNy thin films using 1,3,5-tri(isopropyl)cyclotrisilazane (TICZ, C9H27N3Si3) and soft remote ammonia (NH3) plasma co-reactants. The process involved four pulses: thermal adsorption of TICZ to the substrate at very low temperature, nitrogen (N2) purge, soft NH3 remote plasma step, and N2 purge. These steps were repeated until the desired film thickness was reached. The ratio of C to N in the films was modulated by controlling the substrate temperature in the range of 30 to 200oC. In-situ analysis of the deposition process was carried-out using spectroscopic ellipsometry, and the films were analyzed by x-ray photoelectron spectroscopy (XPS). The findings of this study indicate that the combination of reduced substrate thermal budget and soft remote plasma provides an optimum low energy environment for the controlled deposition of SiCxNy protective coatings on thermally fragile, chemically sensitive substrates, including plastics and polymers.
Spatial Revelations of Chemical and Electrochemical Kinetics into Defect Generations during Semiconductor Processing
Authors: Sheng Lieyi , Pan Wei
Published: September 2020

The unique fundamentals of kinetic phenomena during semiconductor processing have been extensively reviewed for the first time. A comprehensive three-dimensional (3D) view provides several insights into chemical transportations along wafer surface and electrical cross-sections in device stacks. Multiple case studies are detailed in order to illustrate the effectiveness of connecting these unique dynamics with critical defects generated. These spatial revelations have made significant contributions to our solid technology development as well as quality manufacturing.
Interfacial Analysis of Plasma Fusion Bonded Interfaces Under Various Bonding Conditions by Neutron Reflectometry
Authors: Fujino Masahisa , Takahashi Kenji , Kikuchi Katsuya , Miyata Noboru , Yoshida Tessei , Miyazaki Tsukasa
Published: September 2020

Wafer bonding is one of the key technologies for the 3D integrations and fusion bonding requires optimization of varieties of process parameters. In particular, silicon dioxide (SiO2) layer should be activated and hydrophilized properly, and the bonding strength is affected by them. In this research, thermal oxide has been bonded by plasma activated fusion bonding, and neutron reflectometer (NR) has been performed to the bonded interface to detect the reacted interfacial layer during the bonding process. As results, NR could detect the reacted interfacial layer, and each interfacial layer would regard the conditions of SiO2. Therefore, NR analysis is one of the valuable tools to evaluate the bonding interface.
Characterization of Silicon Carbon Nitride for Low Temperature Wafer-to-Wafer Direct Bonding
Authors: Nagano Fuya , Iacovo Serena , Phommahaxay Alain , Inoue Fumihiro , Sleeckx Erik , De Gendt Stefan , Beyer Gerald , Beyne Eric
Published: September 2020

Silicon carbon nitride (SiCN) compounds have aroused great interest as dielectric materials for direct bonding because of the high thermal stability and high bond strength, as well as its Cu diffusion barrier properties. While wafer-to-wafer direct bonding, including the dielectric deposition step, is generally performed at high temperature (>350°C), applications such as heterogeneous chips and DRAMs would require wafer-to-wafer direct bonding at lower temperature (<250°C). In this study, we evaluate, for SiCN deposited at various temperatures, the impact for direct wafer bonding of lowering the temperature of all processes. Chemical and mechanical properties of SiCN direct bonding are studied.
Direct Wafer Bonding Methods: A Practical Process Selection Guide
Authors: Dragoi Viorel , Rebhan Bernhard , Pabo Eric
Published: September 2020

High temperature direct wafer bonding (~1000°C) is used for the manufacturing of various products since early 1990s. The development of low temperature wafer bonding methods (< 400°C) in early 2000s increased significantly the adoption of direct bonding in semiconductor devices manufacturing as it allowed for bonding of wafers fully processed in CMOS technology. Additionally the revival of an older process: surface activated bonding, increased the number of process choice options. The main features of the various direct wafer bonding processes currently available are presented, with the goal to provide helpful knowledge allowing for direct wafer bonding process selection.
Investigation of Post-Bond Distortion in Direct Wafer Bonding
Authors: Ip Nathan , Nagata Atsushi , Kohama Norifumi , Wada Norio , Motoda Kimio
Published: September 2020

Direct wafer bonding process is used in semiconductor manufacturing for heterogeneous integration of devices. When two silicon wafers are directly bonded together, the alignment along the bonded interface is critical to device performance and yield. This paper studies the relative alignment, or post-bond distortion, of a direct wafer bonding process using finite element simulation method. The methodology of constructing a 2D axisymmetric model to calibrate a 3D model is discussed. The simulation results showed that the post-bond distortion was sensitive to upper wafer pre-bond shapes and does not depend on lower wafer shapes. The simulation models enable reduced hardware development costs and time.
200 mm Ge Wafer Production for Oxide-Free Si-Ge Direct Wafer Bonding
Authors: Rebhan Bernhard , Vanpaemel Johannes , Dragoi Viorel
Published: September 2020

Dislocation-free 200 mm diameter germanium wafers were manufactured via Czochralski crystal growth technique. Standard silicon wafers were used to demonstrate the feasibility of oxide-free Ge direct wafer bonding at room temperature. First the native oxides from both wafer surfaces were removed using ion beam sputtering, followed by the transfer of both wafers in ultra-high vacuum to the bonding process station in order to avoid re-oxidation. Subsequently annealing to correct for the sputter-induced amorphization was studied. For the qualification of the process the main focus was on the morphological and elemental analysis of the surfaces and of the bonded interfaces.
Collective Die Bonding: An Enabling Toolkit for Heterogeneous Integration
Authors: Burggraf Jürgen , Uhrmann Thomas , Pires Mariana
Published: September 2020

The increasing demand for high performance devices with increased functionality onto a single device/package and with reduced form factor were the main factors driving the development of heterogeneous integration technology. Heterogeneous integration (HI) refers to the assembly and packaging of multiple separately manufactured components onto a single chip in order to increase functionality. Components with different functionality, substrate materials, and process technologies are joined in a single package in a System in Package (SIP) approach. The functionality of the components could vary throughout the entire device supply chain starting from signal processors to memory, micro-electro-mechanical systems (MEMS), and silicon photonics. The possibility to join multiple functionalities onto a die enables new packaging architectures and design concepts. One such concept is based on the not new concept of die-to-wafer bonding but allows for bonding multiple dies to a wafer in a single process. Packaging is the final manufacturing process transforming devices into functional products for the end user. Packaging must provide electrical and photonic connections for signal input and output, power input, and voltage control. It also provides for thermal dissipation and the physical protection required for increased product reliability. In this work, we report results using a method and process flow enabling local die bonding compatible with the highest alignment accuracy and cleaning requirements to support a very high yield. A customized temporary carrier with alignment features was utilized to place known good dies (KGD) on the carrier and enable die processing prior to the final bonding process.
Selective Heat Input for Low Temperature Metallic Wafer Level Bonding
Authors: Wiemer Maik , Hofmann Christian , Vogel Klaus
Published: September 2020

This paper focuses on two innovative bond technologies, which enable a selective heating of the bond interface only. The reactive bonding with the new CuO/Al multilayer system could by successfully used for wafer bonding. With a tool pressure of 0.5 to 5 bar an average shear strength of 64 N/mm² for Si-glass and 143 N/mm² for Si-Si could be reached. The bond time is < 1 s due reaction velocities of 28 m/s to 40 m/s. The focus of inductive bonding is the support and enhancement of the solid-liquid interdiffusion (SLID) process at wafer level by using selective and energy-efficient induction heating of Cu-Sn layers. With IR thermography, the heat distribution and the achieved heating rate of approx. ∆T = 150 K/s could be investigated. By applying a tool pressure of 2 MPa and a bond time of 120 s an average shear strength of 68 N/mm² could be achieved.
Gas Absorption in Package Using Au/Pt/Ti Bonding Layer
Authors: Matsumae Takashi , Kariya Shingo , Kurashima Yuichi , Takagi Hideki , Hayase Masanori , Higurashi Eiji
Published: September 2020

A packaged environment was fabricated by bonding substrates with the Au/Pt/Ti layers. By annealing at 450°C, Ti diffused through the Pt and Au layers and reacted with residual gas molecule at the inner surface of the package. These results suggested that a cap wafer metalized the Au/Pt/Ti layer can form hermetic sealing with a device substrate and subsequently absorb the residual gas in the package by the activation annealing. It is believed this would contribute to simplified vacuum packaging processes in which getter materials is not necessary.
(Invited) Ferroelectric-HfO2 Devices: Physics and Applications
Authors: Kobayashi Masaharu
Published: September 2020

Newly discovered ferroelectric-HfO2 opens up the new opportunities of low-power, high-speed, and high-density nonvolatile memories. In this paper, our recent research progresses of ferroelectric-HfO2 memories are introduced: nonvolatile SRAM (NVSRAM) for smart power management in IoT applications, ferroelectric tunnel junction (FTJ) for ultimately small memory device, and ferroelectric FET (FeFET) with novel channel material for high-density memory. Challenges and opportunities of each device technology are discussed.
(Invited) Highly Doped Si1-XGex Epitaxy in View of S/D Applications
Authors: Rengo Gianluca , Porret Clement , Hikavyy Andriy Yakovitch , Rosseel Erik , Nakazaki Nobuya , Pourtois Geoffrey , Vantomme Andre , Loo Roger
Published: September 2020

This contribution focuses on S/D epitaxial layers grown and in-situ doped by chemical vapor deposition, and on the properties of fabricated Ti/p-Si1-xGex contacts. The Ti/Si1-xGex:B contact resistivity and the Si1-xGe1-x:B layer resistivity are both minimized for an optimized range of layer thickness. Both parameters increase as the layer relaxes. Preserving strain in Si1-xGex:B S/D material is therefore important. The increase in S/D layer resistivity and contact resistivity with increasing layer thickness is, however, not caused by the (small) increase in electrical band gap induced by (partial) layer relaxation. Instead, B incorporation during epitaxial growth is affected by the initiation of layer relaxation and decreases with increasing degree of strain relaxation. This effect is observed for the whole range of Ge concentrations. The reduced B incorporation results in a lower carrier concentration near the layer surface which, in-turn, explains the increase in contact resistivity and layer resistivity.
(Invited) Tensile Strain Engineering and Defects Management in GeSn Laser Cavities
Authors: EL Kurdi Moustafa , Elbaz Anas , Wang Binbin , Sakat Emilie , Herth Etienne , Patriarche Gilles , Pantzas Konstantinos , Sagnes Isabelle , Sauvage Sebastien , Checoury Xavier , Chelnokov Alexei , Reboud Vincent , Chretien Jeremie , Pauc Nicolas , Calvo Vincent , Boeuf Frédéric , Boucaud Philippe , von den Driesch Nils , Grützmacher Detlev , Hartmann Jean-Michel , Buca Dan
Published: September 2020

Recent achievements of direct band gap with germanium by alloying with tin or by tensile strain engineering has enabled multiple times demonstration of laser emission in the 2-4µm wavelength range. This fast and promising emergence of CMOS-compatible laser technology in the Mid-IR faces, however, major issues, e.g., high power density of thresholds, hindering the aim to be integrated on a silicon chip and develop low cost sensing and/or Datacom devices. In this report we show that combining both tensile strain and Sn alloying can effective engineer the material band structure and its optical gain properties. We also evidence the importance of defects management on GeSn lasing characteristics, beyond the band structure engineering. We discuss the potential of GeSnOI technology to address above aspects, which enabled to drastically reduce the lasing thresholds in microdisk laser cavities and reach continuous-wave operation in GeSn active media.