bluuebunny/crossref_metadata_2025 huggingface dataset:
Functions and Unique Diversity of Genes and Microorganisms Involved in Arsenite Oxidation from the Tailings of a Realgar Mine
Authors: Zeng Xian-Chun , E Guoji , Wang Jianing , Wang Nian , Chen Xiaoming , Mu Yao , Li Hao , Yang Ye , Liu Yichen , Wang Yanxin
Published: September 2016

The tailings of the Shimen realgar mine have unique geochemical features. Arsenite oxidation is one of the major biogeochemical processes that occurs in the tailings. However, little is known about the functional and molecular aspects of the microbial community involved in arsenite oxidation. Here, we fully explored the functional and molecular features of the microbial communities from the tailings of the Shimen realgar mine. We collected six samples of tailings from sites A, B, C, D, E, and F. Microcosm assays indicated that all of the six sites contain both chemoautotrophic and heterotrophic arsenite-oxidizing microorganisms; their activities differed considerably from each other. The microbial arsenite-oxidizing activities show a positive correlation with soluble arsenic concentrations. The microbial communities of the six sites contain 40 phyla of bacteria and 2 phyla of archaea that show extremely high diversity. Soluble arsenic, sulfate, pH, and total organic carbon (TOC) are the key environmental factors that shape the microbial communities. We further identified 114 unique arsenite oxidase genes from the samples; all of them code for new or new-type arsenite oxidases. We also isolated 10 novel arsenite oxidizers from the samples, of which 4 are chemoautotrophic and 6 are heterotrophic. These data highlight the unique diversities of the arsenite-oxidizing microorganisms and their oxidase genes from the tailings of the Shimen realgar mine. To the best of our knowledge, this is the first report describing the functional and molecular features of microbial communities from the tailings of a realgar mine.

IMPORTANCE
This study focused on the functional and molecular characterizations of microbial communities from the tailings of the Shimen realgar mine. We fully explored, for the first time, the arsenite-oxidizing activities and the functional gene diversities of microorganisms from the tailings, as well as the correlation of the microbial activities/diversities with environmental factors. The findings of this study help us to better understand the diversities of the arsenite-oxidizing bacteria and the geochemical cycle of arsenic in the tailings of the Shimen realgar mine and gain insights into the microbial mechanisms by which the secondary minerals of the tailings were formed. This work also offers a set of unique arsenite-oxidizing bacteria for basic research of the molecular regulation of arsenite oxidation in bacterial cells and for the environmentally friendly bioremediation of arsenic-contaminated groundwater.
Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation
Authors: Overton K. Wesley , Park Dan M. , Yung Mimi C. , Dohnalkova Alice C. , Smit John , Jiao Yongqin
Published: September 2016

Surface layers, or S-layers, are two-dimensional protein arrays that form the outermost layer of many bacteria and archaea. They serve several functions, including physical protection of the cell from environmental threats. The high abundance of S-layer proteins necessitates a highly efficient export mechanism to transport the S-layer protein from the cytoplasm to the cell exterior.
Caulobacter crescentus
is unique in that it has two homologous, seemingly redundant outer membrane proteins, RsaF
a
and RsaF
b
, which together with other components form a type I protein translocation pathway for S-layer export. These proteins have homology to
Escherichia coli
TolC, the outer membrane channel of multidrug efflux pumps. Here we provide evidence that, unlike TolC, RsaF
a
and RsaF
b
are not involved in either the maintenance of membrane stability or the active export of antimicrobial compounds. Rather, RsaF
a
and RsaF
b
are required to prevent intracellular accumulation and aggregation of the S-layer protein RsaA; deletion of RsaF
a
and RsaF
b
led to a general growth defect and lowered cellular fitness. Using Western blotting, transmission electron microscopy, and transcriptome sequencing (RNA-seq), we show that loss of both RsaF
a
and RsaF
b
led to accumulation of insoluble RsaA in the cytoplasm, which in turn caused upregulation of a number of genes involved in protein misfolding and degradation pathways. These findings provide new insight into the requirement for RsaF
a
and RsaF
b
in cellular fitness and tolerance to antimicrobial agents and further our understanding of the S-layer export mechanism on both the transcriptional and translational levels in
C. crescentus
.

IMPORTANCE
Decreased growth rate and reduced cell fitness are common side effects of protein production in overexpression systems. Inclusion bodies typically form inside the cell, largely due to a lack of sufficient export machinery to transport the overexpressed proteins to the extracellular environment. This phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates that
Caulobacter crescentus
has two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closest
C. crescentus
homologs to TolC in
E. coli
, do not process TolC functionality in
C. crescentus
.
Destruction of the Wyoming craton: Seismic evidence and geodynamic processes
Authors: Dave Riddhi , Li Aibing
Published: September 2016

Cratons are old and strong continental cores where the lithosphere is thick and remains largely undeformed for 2–3 b.y. Unlike typical cratons, the Wyoming craton underwent pervasive deformation ca. 80–55 Ma during the Laramide orogeny in the west-central United States, and has been subsequently encroached upon by the Yellowstone hotspot since 2.0 Ma. However, the mechanism for the deformation and the craton-hotspot interaction are not well understood. We present here a three-dimensional shear wave velocity model beneath the Wyoming craton constrained from Rayleigh wave data, which reveal new details about the cratonic lithosphere. The average lithosphere thickness beneath the craton is ∼150 km, significantly thinner than a normal cratonic root (>200 km). Continuous low velocities are observed beneath the Yellowstone hotspot and the Cheyenne belt. A low-velocity column is also present in the central-eastern craton at depths of 115–250 km. These low velocities can be explained by hot temperature and partial melting, implying mantle upwelling. A high-velocity anomaly with a dripping shape in central Wyoming extends to 200–250 km depth, indicating mantle downwelling and lithosphere erosion. Our model provides the first seismic evidence for complex small-scale mantle convection beneath the Wyoming craton. The convection probably developed during the subduction of the Farallon plate and has been reinforced by the Yellowstone hotspot. We propose that the combination of flat-slab subduction, small-scale convection, and hotspot activity can lead to massive destruction of a cratonic lithosphere.
Long-term cardiovascular outcome following fetal anaemia and intrauterine transfusion: a cohort study
Authors: Wallace Alexandra H , Dalziel Stuart R , Cowan Brett R , Young Alistair A , Thornburg Kent L , Harding Jane E
Published: September 2016

Objective

To compare long-term cardiovascular outcomes in survivors of fetal anaemia and intrauterine transfusion with those of non-anaemic siblings.

Design

Retrospective cohort study.

Setting

Auckland, New Zealand.

Participants

Adults who received intrauterine transfusion for anaemia due to rhesus disease (exposed) and their unexposed sibling(s).

Exposure

Fetal anaemia requiring intrauterine transfusion.

Main outcome measures

Anthropometry, blood pressure, lipids, heart rate variability and cardiac MRI, including myocardial perfusion.

Results

Exposed participants (n=95) were younger than unexposed (n=92, mean±SD 33.7±9.3 vs 40.1±10.9 years) and born at earlier gestation (34.3±1.7 vs 39.5±2.1 weeks). Exposed participants had smaller left ventricular volumes (end-diastolic volume/body surface area, difference between adjusted means −6.1, 95% CI −9.7 to −2.4 mL/m2), increased relative left ventricular wall thickness (difference between adjusted means 0.007, 95% CI 0.001 to 0.012 mm.m2/mL) and decreased myocardial perfusion at rest (ratio of geometric means 0.86, 95% CI 0.80 to 0.94). Exposed participants also had increased low frequency-to-high frequency ratio on assessment of heart rate variability (ratio of geometric means 1.53, 95% CI 1.04 to 2.25) and reduced high-density lipoprotein concentration (difference between adjusted means −0.12, 95% CI −0.24 to 0.00 mmol/L).

Conclusions

This study provides the first evidence in humans that cardiovascular development is altered following exposure to fetal anaemia and intrauterine transfusion, with persistence of these changes into adulthood potentially indicating increased risk of cardiovascular disease. These findings are relevant to the long-term health of intrauterine transfusion recipients, and may potentially also have implications for adults born preterm who were exposed to anaemia at a similar postconceptual age.
C9orf72 expansion differentially affects males with spinal onset amyotrophic lateral sclerosis
Authors: Rooney James , Fogh Isabella , Westeneng Henk-Jan , Vajda Alice , McLaughlin Russell , Heverin Mark , Jones Ashley , van Eijk Ruben , Calvo Andrea , Mazzini Letizia , Shaw Christopher , Morrison Karen , Shaw Pamela J , Robberecht Wim , Van Damme Phillip , Al-Chalabi Ammar , van den Berg Leonard , Chiò Adriano , Veldink Jan , Hardiman Orla
Published: September 2016

Introduction

TheC9orf72repeat expansion has been reported as a negative prognostic factor in amyotrophic lateral sclerosis (ALS). We have examined the prognostic impact of theC9orf72repeat expansion in European subgroups based on gender and site of onset.

Methods

C9orf72status and demographic/clinical data from 4925 patients with ALS drawn from 3 prospective ALS registers (Ireland, Italy and the Netherlands), and clinical data sets in the UK and Belgium. Flexible parametric survival models were built including known prognostic factors (age, diagnostic delay and site of onset), gender and the presence of an expanded repeat inC9orf72.These were used to explore the effects ofC9orf72on survival by gender and site of onset. Individual patient data (IPD) meta-analysis was used to estimate HRs for results of particular importance.

Results

457 (8.95%) of 4925 ALS cases carried theC9orf72repeat expansion. A meta-analysis ofC9orf72estimated a survival HR of 1.36 (1.18 to 1.57) for those carrying the expansion. Models evaluating interaction between gender andC9orf72repeat expansions demonstrated that the reduced survival due toC9orf72expansion was being driven by spinal onset males (HR 1.56 (95% CI 1.25 to 1.96).

Conclusions

This study represents the largest combined analysis of the prognostic characteristics of theC9orf72expansion. We have shown for the first time that the negative prognostic implication of this variant is driven by males with spinal onset disease, indicating a hitherto unrecognised gender-mediated effect of the variant that requires further exploration.
Variance-Based Sensitivity of Localized Sulphation to Microporous Separator Properties Using a Distributed Parameter Model of a Valve-Regulated Lead-Acid Battery
Authors: Janse van Rensburg Angelique , van Schoor George , van Vuuren Pieter Andries
Published: September 2016

Progressive sulphation of the negative electrode in a lead-acid battery under high-rate operation remains a serious problem. This study investigates how healthier end-of-discharge conditions, in a valve-regulated lead-acid battery with an immobilized electrolyte, can be achieved by calculated changes in the separator’s porosity, thickness and tortuosity. The solubility, volume fraction and geometry factor of local PbSO4 crystals are modeled using a distributed parameter model and observed during a high-rate discharge in simulation. A variance-based sensitivity analysis, consisting of a Monte Carlo experiment and Jansen’s formulae for variance decomposition, is performed to quantify the effects of separator design on localized sulphation. The concentration profile across different regions of the cell is also briefly examined by means of a statistical equation for the concentration non-uniformity. The results indicate that the separator thickness has the greatest effect on the PbSO4 crystals at the negative electrode because it severely influences the concentration profile in this region. The simulation results also indicate that separator design with the aim of manipulating the concentration profile, and enabling faster homogenization within a lead-acid cell, can be achieved. We conclude that it is possible to design a microporous separator that improves the dissolution, during recharge, of the PbSO4 crystals on the negative electrode that initially formed during a high-rate discharge. The quantitative approach we have followed can be used to quickly evaluate thousands of different separator designs and determine a suitable starting point for experimental work.
Control of the Magnetic Properties of a Magnetic Field Guidable Biocompatible Nanovehicle
Authors: Granitzer Petra , Rumpf Klemens , Reissner Michael , Poelt Peter
Published: September 2016

Within this work a biocompatible magnetic nanovehicle which is movable in aqueous solutions by a magnetic field is presented. The nanovehicle consists of a porous silicon template and encapsulated iron oxide nanostructures. Both materials employed, porous silicon (PSi) as well as iron oxide are known to be biocompatible. Two routes are employed to produce various iron oxide phases of the embedded nanostructures within PSi. On the one hand, readily synthesized magnetite nanoparticles (NPs) which are superparamagnetic (SPM) due to their size, are infiltrated into the pores. On the other hand chemical deposition of iron oxide inside the PSi templates is used. Mainly the synthesis of the nanocomposite as well as the magnetic properties of the systems will be discussed.
(Invited) Porous Silicon Dissolution Monitoring and Optical Constants Measurement Using in Situ Photoconduction in HF
Authors: Gelloz Bernard , Ichimura Kazuki , Fuwa Hiroki , Kondoh Eiichi , Jin Lianhua
Published: September 2016

The progress of the chemical dissolution of porous silicon (PSi), formed from lightly-doped p-type silicon, in HF was monitored by recording in situ the photocurrent from a monochromatic illumination. The photocurrent is a signature of the optical transmission of the illumination in the substrate underneath PSi. The time corresponding to complete PSi dissolution is easily identified by a plateau of photocurrent. The effects of HF concentration, PSi porosity and PSi thickness were studied. The PSi dissolution rate is discussed. Using a model, the relations between the dissolution time, the porosity, and the absorption coefficient are elucidated. The effects of both PSi structure topology and quantum confinement on the optical absorption of PSi are discussed. The methods shown here allow the study of very high porosities while still having a clean hydrogen-terminated PSi surface and very good structural integrity, since PSi is never dried or exposed to air.
Pit Formation, Patterning and Flattening of Ge Surfaces in O2-Containing Water by Metal-Assisted Chemical Etching
Authors: Kawase Tatsuya , Mura Atsushi , Saito Yusuke , Okamoto Takeshi , Kawai Kentaro , Sano Yasuhisa , Yamauchi Kazuto , Morita Mizuho , Arima Kenta
Published: September 2016

Metal-assisted chemical etching is a novel method of etching a Ge surface in contact with a noble metal in water. Its basic mechanism involves the catalytic activity of metals to reduce dissolved O2 molecules in water, which accompanies the formation of a soluble oxide (GeO2) on the Ge surface around the metal. Here, we apply this electroless etching to the pit formation, nanoscale patterning and surface flattening of Ge. The fundamental etching properties for these three processes are also presented.
PbS Quantum Dots and Au Nanoparticle Co-Sensitized Black TiO2 Nanotubes for Photocurrent Enhancement
Authors: Du Kang , Liu Guohua , San Haisheng , Chen Xuyuan , Wang Kaiying
Published: September 2016

In order to extend absorption to visible light spectrum, black TiO2 nanotubes (TNT) were synthesized by electrochemical reduction of anodized anatase TNT. Subsequently, Au nanoparticles (NPs) and PbS quantum dots (QDs) as light-harvesting antennae were co-sensitized on black TNT by magnetron sputter technique and dip coating approach. The nanocomposites H-TNT-Au-PbS display strong absorption in the wavelength above 400nm. As a result, the photocurrent density of H-TNT-Au-PbS was enhanced by 89.1% comparing with that of pristine TNT under visible illumination. This study could offer a low-cost and simple process for fabricating visible-driven photocatalysts with better performance and good stability.
Superconformal Bottom-up Nickel Deposition in High Aspect Ratio through Silicon Vias
Authors: Josell Daniel , Moffat Thomas P.
Published: September 2016

This work demonstrates void-free nickel filling of 56 μm tall, annular Through Silicon Vias (TSVs) using a mechanism that couples suppression breakdown and surface topography to achieve controlled superconformal, void-free deposition. The chemistry, a Watts electrolyte containing a dilute suppressing additive, and processes are fully detailed. The impact of deposition potential and additive concentration on the filling of the patterned features is presented. Voltammetric measurements on planar substrates, including the impact of rotation rate and suppressor concentration on the rate of metal deposition and potential of suppression breakdown, are used to quantify the interplay between metal deposition and suppressor adsorption. The derived kinetics are then used to quantitatively predict the observed bottom-up filling in the TSVs using the S-shaped negative differential resistance (S-NDR) mechanism for superconformal deposition; the predictions capture the experimental observations. This work extends understanding and application of the additive-derived S-NDR mechanism developed with non-ferrous metals.
Electrodeposition of Magnetic SmCo Films from Deep Eutectic Solvents
Authors: Panzeri Gabriele , Magagnin Luca
Published: September 2016

SmCo alloys have attracted attention for their high Curie temperature, magnetic anisotropy and relatively high saturation magnetization. Because of the very negative reduction potential of Sm in aqueous solution, its electrodeposition is problematic due to strong hydrogen evolution at the cathode surface. Deep eutectic solvent solution of 1 choline chloride: 2 ethylene glycol is studied as alternative solution to aqueous solvents for the electrodeposition of SmCo alloys. This study is focused on the deposition process of the alloy; variable Sm% contents are obtained depending on the experimental conditions e.g. bath formulation, deposition voltage and stirring condition.
(Invited) Biological Applications of Magnetic Nanoparticles for Magnetic Immunoassay and Magnetic Particle Imaging
Authors: Yoshida Takashi , Sasayama Teruyoshi , Enpuku Keiji
Published: September 2016

Here, we introduce the application of magnetic nanoparticles (MNPs) for magnetic immunoassay and magnetic particle imaging (MPI). First, we present a liquid-phase magnetic immunoassay system that uses the difference in Brownian relaxation between bound and unbound magnetic particles. We found that the minimum detectable molecular number concentration of the developed magnetic immunoassay system is 3.6 × 10−18 mol/mL. We then studied the effect of the alignment of the easy axes on the performance of the MPI. Although the detection sensitivity can be improved by using an aligned MNP sample, the spatial resolution of the aligned sample strongly depends on the direction of alignment of the easy axes.
Electrochemical CO2 Reduction in Ionic Liquid Using Two Compartment Cell Separated with Proton-Conducting Membrane
Authors: Yoshikawa Hayato , Azumi Kazuhisa
Published: September 2016

Electrochemical conversion of CO2 to CH4 using EMIM-TFSI ionic liquid bath was investigated. EMIM-TFSI can absorb much CO2 gas and thus used as an electrolyte solution. To maximize conversion efficiency, two compartment cell was developed in which ionic liquid bath containing Cu mesh working electrode bubbled with CO2 gas and KCl aqueous solution bath containing counter electrode were separated by proton conducting Nafion membrane. Suitable condition of water content in the ionic liquid bath and polarization potential for efficient conversion was investigated by using gas chromatography. Spatial arrangement working electrode and membrane was also shown to be an important factor for efficient conversion from CO2 to CH4.
Substitutional Carbon Loss in Si:C Stressor Layers Probed by Deep-Level Transient Spectroscopy
Authors: Simoen Eddy , Dhayalan Sathish Kumar , Hikavyy Andriy Yakovitch , Loo Roger , Rosseel Erik , Vrielinck Henk , Lauwaert Johan
Published: September 2016

This paper reports on a Deep-Level Transient Spectroscopy (DLTS) study of the electrically active defects formed by chemical vapor deposition of ~100 nm Si:C stressors on p-type Czochralski silicon substrates. In addition, the impact of a post-deposition Rapid Thermal Annealing (RTA) at 850 oC is investigated. It is shown that a dominant hole trap is found in the silicon depletion region, with an activation energy of 0.4 eV with respect to the valence band and assigned to CiOi. This indicates the presence of interstitial carbon (Ci), injected from the Si:C epi layer. It is demonstrated that the concentration of CiOi increases significantly after the RTA treatment, indicating that more carbon is driven out of lattice sites in the stressor. In addition, a second broad peak appears in the spectra, when biasing close to the epitaxial layer/substrate interface, demonstrating the presence of a band of hole traps which could be associated with precipitated carbon.
(Invited) Non-Visual Defect Monitoring with Surface Photovoltage Mapping
Authors: Findlay Andrew David , Marinskiy Dmitriy , Edelman Piotr , Wilson Marshall , Savtchouk Alexandre , Almeida Carlos , Lagowski Jacek
Published: September 2016

Non-Visual Defects (NVD) is a category of semiconductor material and process induced defects that cause electrical failures, but are not detected with visual wafer inspection tools. This paper gives an overview of our non-contact electrical NVD metrology that uses fast whole wafer inspection with standard mm resolution Kelvin probe surface voltage mapping. In an advanced approach the detected NVD regions are imaged in high resolution (mm range) using Force Kelvin Probe Microscopy. In depth NVD characterization is done with the corona-Kelvin method that quantifies dielectric and interfacial properties in the defect sites. This characterization is performed in a non-invasive fluence range of corona charging and all measurements are non-contact, and do not require fabrication of test devices. Principles of non-contact surface voltage are explained for whole wafer mapping using a high throughput dual Kelvin-probe approach, and for high-resolution micro-Kelvin Force Probe mapping of defect sites. Application examples are discussed in chronological order of the metrology development, starting with monitoring of plasma damage first introduced about 20 years ago. Further examples include surface voltage mapping of surface alkali-metals including novel high resolution micro-Kelvin Force Probe results. Recent trends in monitoring are illustrated with patterned wafer mapping and micro-scale intra die NVD’s. Finally an extension of the technique to defect mapping in SiC is presented together with in-depth corona-Kelvin characterization of defect sites. A broad application range is demonstrated with examples relevant to silicon IC, silicon photovoltaics and to wide bandgap epitaxial SiC.
Practical Evaluation Method of Oxygen Precipitation in the Czochralski Silicon
Authors: Lee Anselmo Jaehyeong , Hong Sejun , Kim Ja-Young , Kang Hee-Bog , Lee Sung-Wook
Published: September 2016

A simple, practical way to evaluate process-induced oxygen precipitates was investigated. Effective values of fastest nucleation point (TC
,
J
max) were derived as parameters of precipitate densities from the as-grown oxygen precipitate nuclei distributions by fitting them into the cumulative function F(T) of the nucleation rate J = J(Oi, CV, T). Precipitate densities were clearly explained by TC and J
max in the entire Oi and point defect region. From the relations of Oi and Cv on the fastest nucleation point in the nucleation rate, TC is closely related to the CV and expected as a potential indicator of evaluating the practical CZ-Si manufacturing.
(Invited) Modeling Extended Defects in Semiconductor Devices
Authors: Moroz Victor , Wong Hiu Yung , Choi Munkang
Published: September 2016

The most widely used in the industry stress engineering technique is based on introducing crystal lattice mismatch stress by growing SiGe on Si. For the power switches, GaN is epitaxially grown on an AlGaN buffer on top of Si wafer. The lattice mismatch stress can be high enough to introduce edge dislocations and stacking faults. We perform analysis of several key aspects of the extended defect formation and their impact on silicon and GaN transistors. We demonstrate modeling methodology to determine where a stacking fault is going to move driven by a stress gradient. Once a dislocation has found its energetically favorable location, it can be either inside or outside of the area sensitive to transistor performance. We explore the impact of a dislocation on the carrier scattering for the on-state current of advanced Si CMOS transistors and the impact of threading dislocations on power GaN switches.
(Invited) Straining of Group IV Semiconductor Materials for Bandgap and Mobility Engineering
Authors: Sawano Kentarou , Xu Xuejun , Konoshima Shiori , Shitara Nayuta , Ohno Takeshi , Maruizumi Takuya
Published: September 2016

Various methods to induce tensile and compressive strains into group IV semiconductors have been intensively studied toward high performance and low-power consumption electronic and photonic devices. Among them, here we show our approaches to induce uniaxial strain by local defect introduction and enhanced tensile strain by wafer bonding and microbridge fabrication.
Building III-V Devices onto Large Si Wafers
Authors: Bao Xin-Yu , Ye Zhiyuan , Carlson David , Sanchez Errol
Published: September 2016

This paper reviewed the process developments when building III-V devices onto large Si wafers using Applied Materials’ 300mm III-V metal-organic chemical vapor deposition tool (MOCVD). Anti-phase defects free GaAs films were achieved by optimizing the surface pre-cleaning and growth conditions on industrial standard 300mm Si (100) wafers. High quality growth on patterned wafers was also demonstrated for III-V FinFET applications.
Density Functional Theory Study on Frenkel Pair Formation from Oxygen Clusters in Si Crystal
Authors: Fukuda Hiroaki , Sueoka Koji
Published: September 2016

Silicon (Si) wafers, which are the most widely used semiconductors for integrated circuit fabrication, are produced by polishing after slicing Czochralski (CZ) grown Si ingots. Oxygen (O) atoms with a concentration of 1×1018 atom/cm3 are incorporated from the melt of Si charged in the SiO2 crucible during crystal growth. The interstitial Oi atoms precipitate in the subsequent heat treatments and grow into oxide precipitates (SiOx). It is well known that self-interstitial (I) atoms are emitted from growing oxide clusters. In this emission, a remaining vacancy (V) contributes to relieve the compressive lattice strain around oxide clusters. That is, the Frenkel pair (self-interstitial I and vacancy V) formation occurs at oxygen clusters. Since these emitted atoms interact with dopant atoms, impurities, lattice defects, etc., and affect the performance of Si wafers, the mechanism of I emission from Oi clusters should be clarified and taken into consideration in the computer simulation of oxygen precipitation. In this study, we analyzed the Frenkel pair formation with and without oxygen clusters in Si crystal by density functional theory (DFT) study.
(Invited) Conductive Bridging RAM (CBRAM): Then, Now, and Tomorrow
Authors: Jameson John R. , Blanchard Philippe , Dinh John , Gonzales Nathan , Gopalakrishnan Vasudevan , Guichet Berenice , Hollmer Shane , Hsu Sue , Intrater Gideon , Kamalanathan Deepak , Kim David , Koushan Foroozan , Kwan Ming , Lewis Derric , Pedersen Bård , Ramsbey Mark , Runnion Ed , Shields Jeffrey , Tsai Kevin , Tysdal Aaron , Wang Daniel , Gopinath Venkatesh
Published: September 2016

Conductive bridging RAM (CBRAM) is a resistive memory technology (RRAM) offering performance, power/energy, reliability, and cost advantages over incumbent nonvolatile memory technologies. The present article introduces the class of CBRAM in high-volume manufacturing today—subquantum CBRAM—and highlights similarities and differences between it and its predecessors. The materials requirements of subquantum CBRAM cells are described, and new insight into the switching mechanism is provided. Finally, its electrical characteristics are benchmarked, and its suitability for applications such as embedded memory, the Internet of Things (IoT), and radiation-tolerant electronics is summarized.
Local Thinning Induced Less Oxide Breakdown in MOS Structures Due to Lateral Non-Uniformity Effect
Authors: Lin Huang-Hsuan , Hwu Jenn-Gwo
Published: September 2016

The reliability of MOSCAPs with ultrathin gate oxide is investigated by constant voltage stress tests. The results show that the degradation behavior in gate oxide can be reduced by introducing lateral non-uniformity in oxide thickness to obtain lower sustaining electric field in oxide layer. The strong oxide field transition region between 2.5 nm and 3.5 nm SiO2 thickness is believed to be the origin for the observed degradation behavior, as confirmed by TCAD simulations.
Current Coupling Effect in MIS Tunnel Diode with Coupled Open-Gated MIS Structure
Authors: Liao Chien-Shun , Hwu Jenn-Gwo
Published: September 2016

Coupled current-voltage behaviors were observed in a metal-insulator-semiconductor (MIS) tunnel diode with an open-gated MIS structure coupled nearby. The MIS tunnel diode is an Al/SiO2/Si(p) structure. For thicker oxides (around 3 nm), the saturation currents of the two neighboring MIS tunnel diodes (with several micrometers separation) were found the same even though the device areas were over 45 times different between them. The tunneling current of the Al/SiO2/Si(p) tunnel diode is exponentially dependent on the effective Schottky barrier height of holes, which depends on the oxide voltage determined by the electron concentration at the substrate surface. Also, the tunneling current of the Al/SiO2/Si(p) tunnel diode is mainly flowing along the device perimeter due to the fringing field effect. In short, the electron concentration at the substrate surface at the device edge determines the tunneling current of the Al/SiO2/Si(p) tunnel diode, which is the key mechanism to explain the coupled phenomenon.
(Invited) First-Principles Study on Electron Conduction at 4H-SiC(0001)/SiO2 Interface
Authors: Ono Tomoya , Kirkham Christopher , Iwase Shigeru
Published: September 2016

The thermal oxidation process of a hydrogen-terminated 4H-SiC(0001) substrate is examined by performing the first-principles total-energy calculations based on the density functional theory. It is found that the oxidation process of a SiC(0001) substrate is different from that of a Si substrate, which proceeds in a layer-by-layer manner. CO2 molecules are mainly emitted from the SiC surface although CO2 emission becomes less favorable and CO molecules are emitted from the SiC/SiO2 interface. Except for the oxidation energy, the situation is the same with the case of a bare 4H-SiC(0001) surface. We conclude that the effect of the dangling bonds on the surface is marginal and the stress at the interface is responsible for the removal of C during the oxidation.
(Invited) Recent Progress in Vertical Si/III-V Tunnel FETs: From Fundamentals to Current-Boosting Technology
Authors: Tomioka Katsuhiro , Motohisa Junichi , Fukui Takashi
Published: September 2016

Tunnel field-effect transistors (TFETs) with a steep subthreshold-slope (SS) are promising low-power switches for future large-scale integrated circuits (LSIs) with low power consumption and high performance. Recently, we demonstrated vertical TFETs with III-V/Si heterojunctions. This new sort of tunnel junction achieves a steep SS because of its unique figure-of-merit. Here, we report on recent progress on vertical TFETs using Si/III-V heterojunctions and means for boosting on-state current.
Electrically Scaled Hafnium Oxide Based Ge Devices
Authors: Tapily Kandabara , Dey Sonal , Consiglio Steven , Clark Robert D. , Wajda Cory S. , Leusink Gert J. , Diebold Alain C.
Published: September 2016

HfxZr1-xO2 (0≤x≤1) films with different Hf/(Hf+Zr) ratios were deposited on Al2O3 passivated Ge by atomic layer deposition (ALD) combined with a cyclical deposition and annealing scheme (termed DADA) in which an annealing was performed after every 20 ALD cycles. A post microwave plasma treatment was conducted after the high-k deposition. Metal oxide semiconductor capacitors (MOSCAPs) using ALD TiN metal gates were fabricated to investigate the electrical properties of the ALD HfxZr1-xO2 thin films. The electrical measurements show significant electrical benefits compared to samples that were not deposited using method described above. The electrical results were corroborated by synchrotron X-ray diffraction measurement
Silicene Nanoribbon Tunnel Field Effect Transistor
Authors: Fahad Md S , Srivastava Ashok , Sharma Ashwani K , Mayberry Clay , Mohsin K M
Published: September 2016

Stable room temperature operation of field effect transistor (FET) based on two-dimensional silicon (silicene) has recently been reported. Like graphene, silicene is a Dirac cone material. Silicene-based devices provide high off-state leakage current due to lack of a significant bandgap. However, quantum confined silicene nanoribbon (SiNR) shows observable bandgap which can be used for making switching transistors for digital integrated circuit design. Contrary to metal oxide semiconductor FET (MOSFET), tunnel field effect transistor (TFET) overcomes the physical limit of scaling of supply voltage. In this work, we present structure and characteristics of SiNR TFET using atomistic simulation based on self-consistent solution of 3D Poisson and Schrödinger equations within the non-equilibrium Green’s function (NEGF) formalism. Performances are also compared with the International Technology Roadmap for Semiconductors (ITRS) projected high performance requirements of 2026 nMOSFETs.
Advanced Wet Clean Technology at Lightly Doped Drain Layers in FinFET
Authors: Li Jian , Sih Vincent , Zhan Hui
Published: September 2016

An advanced wet clean method to utilize piezoelectric nozzle head for fine-controlled dual-fluid sprays based on single wafer clean toolset was demonstrated on FinFET production wafers that surface particles were reduced by as much as 26% without sacrifice of gate pattern damage in sensitive lightly doped drain layers. Additionally, about 5% yield improvement was observed for using the new clean method. The fine-controlled dual-fluid sprays improved the cleaning efficiency significantly in the "physicochemical" way and reduced the potential for pattern damage caused by variations in liquid droplet size and velocity.
Oxidizing Species Dependence of the Interface Reaction during Atomic-Layer-Deposition Process and Post-Deposition-Anneal
Authors: Suwa Tomoyuki , Teramoto Akinobu , Koda Yasumasa , Saito Masaya , Sugita Hisaya , Hayashi Marie , Tsuchimoto Junichi , Ishii Hidekazu , Shiba Yoshinobu , Shirai Yasuyuki , Sugawa Shigetoshi
Published: September 2016

The influence of the post deposition anneal (PDA) to the Al2O3 film quality was investigated. In the case of PDA using Ar/O2 plasma, the Al2O3/substrate interface quality was degraded because the oxidation at Al2O3/substrate interface proceeds. In the case of PDA using H2O, the gate leakage current can be decreased. However, H2O annealing induced the voltage dependence of capacitance due to increase the traps in the Al2O3 film. It is considered that the H2O annealing is effective to reduce the gate leakage current and fixed charges in the Al2O3 film but is induced to increase the traps in the film.
First Principles Study on the Strain Dependence of Thermal Oxidation and Hydrogen Annealing Effect at Si/SiO2 Interface in V-MOSFET
Authors: Shingo Kawachi , Shirakawa Hiroki , Araidai Masaaki , Kageshima Hiroyuki , Endoh Tetsuo , Shiraishi Kenji
Published: September 2016

Gate insulator of vertical MOSFET (V-MOSFET) is formed by silicon oxide. However, Si pillar cannot keep the structure during oxidation process because the Si atoms disappear from bulk (missing-Si). Moreover, the effect of hydrogen annealing for V-MOSFET under the typical condition becomes weaker than that for planer MOSFET. In this study, we revealed the physical origin of missing-Si and hydrogen annealing effects by using first principles calculation method. We considered that the strain which is accumulated at the Si/SiO2 interface in V-MOSFET due to pillar structures. In this study, we clarified the strain dependence of thermal oxidation of V-MOSFET based on the Si-emission model [1,2]. The obtained results indicate that the compressive strain is one of the causes of the missing-Si. Furthermore, we investigated the strain dependence of the effect of hydrogen annealing. As a result, we revealed that hydrogen annealing temperature of VMOSFET should be lower than that of planer-MOSFET.
Vertically Integrated ZRAM toward Extremely Scaled Memory
Authors: Lee Byung-Hyun , Ahn Dae-Chul , Kang Min-Ho , Jeon Seung-Bae , Bang Tewook , Bae Hagyoul , Park Jun-Young , Hong Dae-Won , Park Nam-Soo , Choi Yang-Kyu
Published: September 2016

This paper discusses the demonstration of a vertically integrated gate-all-around (GAA) silicon nanowire (SiNW) channel-based dynamic random access memory (DRAM) without a cell-capacitor as a breakthrough for conventional DRAM scaling. Owing to the one-route all-dry etching process (ORADEP) with stiction-free stability and process simplicity, vertical integration of multiple silicon nanowire was achieved with high uniformity and high reproducibility. Finally, high performance suitable for further scaling was presented in zero-capacitor DRAM (ZRAM) operable with up to five-story SiNW channels without sacrificing scalability.
(Invited) Plasma-Enhanced Quasi-ALE and ALD Processing for Leading-Edge Microfabrication
Authors: Honda Masanobu , Katsunuma Takayuki , Tabata Masahiro , Tsuji Akihiro , Oishi Tomoyuki , Hisamatsu Toru , Ogawa Shuhei , Kihara Yoshihide
Published: September 2016

We introduce a state-of-the-art self-aligned contact (SAC) process and patterning process developed by new patterning technology using Atomic Layer Etch (ALE) and Atomic Layer Deposition (ALD) towards 5/7nm generation. SAC process is known to require SiO2 etching capability with ultra-high selectivity to SiN. We developed Quasi-ALE technique to improve ALE process to make it more suitable for SiO2 Etch. By adopting this technology to SAC process, the conventional trade-offs between fine process control and SiO2 selectivity to SiN in the fine slit pattern is significantly improved. On the other hand, in the patterning process, CD shrink technique without CD loading is one of the key requirements. By integrating ALD process into the etching flow, we developed a process that can control the CD shrink amount in the atomic layer level without causing CD loading.
Plasma-Enhanced Atmospheric-Pressure Spatial ALD of Al2O3 and ZrO2
Authors: Creyghton Yves , Illiberi A. , Mione A. , van Boekel W. , Debernardi N. , Seitz M , van den Bruele Fieke , Poodt P. , Roozeboom Fred
Published: September 2016

Non-thermal plasma sources are known to lower the operation temperatures and widen the process windows in thermal ALD of thin-film materials. In spatial ALD, novel plasma sources with exceptional dimensional and chemical stability are required to provide the flow geometries optimized for efficient transport and use of radicals (O, N, H, OH, NH, etc.).This paper describes our preliminary efforts to provide and examine the required linear scalable plasma sources in spatial ALD reactors. The effectiveness of close-proximity direct and remote plasma sources was demonstrated for thin dielectric films of Al2O3 and ZrO2 deposited at temperatures ranging from 20 to 100°C. Both direct and remote SDBD-type (Surface Dielectric Barrier Discharge) plasma sources were applied using conventional metal precursors and O2/N2 plasma. The remote plasma designs proved advantageous in avoiding electrical source-substrate interactions which often result in layer or substrate damage caused by filamentary plasma discharges impacting the substrate.
(Invited) Atomic Layer Deposition of Multiferroic Materials
Authors: Chang Jeffery , Pham Calvin D , Chang Jane P.
Published: September 2016

The introduction of novel and functionally improved materials into silicon based integrated circuits is a major driver to enable the continued down-scaling of circuit density and performance enhancement in analog, logic, memory and sensing devices. Many novel materials, such as multiferroics, magnetic materials and phase change materials, are introducing new and unique functionalities to further technological advancement. Leveraging the self-limiting surface reactions in atomic layer deposition process, complex materials can be synthesized not only with elemental precision to achieve the desired functionality but also with outstanding conformality to ensure superior interface coupling. The latter enables the integration of ferroelectrics with ferromagnetics to realize multiferroism and magnetoelectric effect for applications in memory, antenna and motors.
(Invited) ALD to Prevent Metal Transfer from Implants
Authors: Borgese Laura , Bilo Fabjola , Zacco Annalisa , Bontempi Elza , Pasquali Michela , Federici Stefania , Prost Josef , Rauwolf Mirjam , Turyanskaya Anna , Streli Christina , Kregsamer Peter , Wobrauschek Peter , Depero Laura Eleonora
Published: September 2016

Atomic layer deposition (ALD) coatings are used in this work to achieve beneficial effects on the surface of CoCrMo alloys used for biomedical applications. Model experiments of implantation into animal bone tissue are performed with uncoated and TiO2 coated samples. Micro X-ray fluorescence is used to map the elemental composition of samples. Results show barrier effect of the coating against the movement of metals from the implant toward the surrounding tissue, increasing with thickness. Moreover, the presence of TiO2 increase the corrosion resistance of the implant. Additional experiments proof that the transfer of ionic species through the same coating, in liquid environment may be exemplified as diffusion through continuous layer, which is also strictly controlled by the coating layer thickness. These evidences open several possibilities for the development of layer by layer structures, with tunable properties, making ALD a powerful tool for biomedical applications.
Synthesis of Cerium-Oxide Coated Platinum Core-Shell Structure Catalysts with Enhanced Stability and Activity via Atomic Layer Deposition
Authors: Cao Kun , Shi Lu , Cai Jiaming , Shan Bin , Chen Rong
Published: September 2016

Cerium oxide has been deposited on the platinum nanoparticles’ to form core shell structures which enhance the metal nanoparticles thermal stability as well as catalytic activity. It is found that growth rate of cerium oxide on Pt surface is faster than on alumina oxide support and form abundant Pt/cerium oxide interfaces. The catalytic performance of Pt/cerium oxide catalysts towards CO oxidation has been investigated in a micro flow reactor. The cerium oxide decorated Pt nanoparticles has demonstrated lower conversion temperature than bare Pt nanoparticles. Moreover the coated Pt nanoparticles show good sintering resistance up to 700 °C under atmosphere condition.
Behavior of La0.6sr 0.4Co0.2Fe0.2O3-δ Cathode Powders Surface Modified by Atomic Layer Deposition for Solid Oxide Fuel Cells
Authors: Roeder Jeffrey F. , Zeberoff Anthony F , Van Buskirk Peter C , Torabi Alireza , Barton Joseph , Willman Carl , Ghezel-Ayagh Hossein , Huang Kevin
Published: September 2016

Atomic layer deposition (ALD) has been used to modify the surfaces of La0.6Sr0.4Co0.2Fe0.2O3-δ (LSCF) cathode powders with gadolinium doped ceria (GDC), zirconia, and cobalt doped zirconia (CDZ). Sintered porosities were ~41% for uncoated LSCF and 37-39% for surface modified powders. Mercury probe analysis showed similar pore size distributions. Symmetrical electrochemical cells showed marked improvements in polarization for the surface modified powders. GDC and CDZ coatings decreased polarization by up to 51 and 61%, respectively, at 800°C. Equivalent circuit modeling suggested little effect on gas diffusion through the porous structure, consistent with similar porosity values. Intermediate and high frequency contributions were significantly affected, suggesting a strong positive impact of the surface modification on both non-charge-transfer properties and charge-transfer properties. A pre-fabricated symmetrical cell treated with GDC via ALD showed very similar behavior to a symmetrical cell fabricated from surface modified GDC.
(Invited) UTBB FDSOI PMOSFETs Including Strained SiGe Channels at the 14nm Technology Node and Beyond
Authors: Andrieu François , Berthelon Remy , Morvan Simeon , Gourhant Olivier , Baylac Elise , Le Royer Cyrille , Dutartre Didier , Josse Emmanuel , Haond Michel
Published: September 2016

We have physically and electrically characterized pMOSFETs of compressively strained SiGe channel built on Ultra-Thin-Body and Buried-Oxide Fully-Depleted-Silicon-On-Insulator (UTBB FDSOI). Such a channel greatly contributes to the FDSOI CMOS high-performance at the 14nm node. At the same time, it induces strong layout effects, which are reported and explained in this paper. They can be reproduced by an accurate physics-based electrical model, which enables us to predict the device and design performance for various technological configurations: germanium concentration in the channel, isolation and channel process integration. In order to mitigate the impacts of the SiGe channel relaxation, we have studied two kinds of solutions. First, technological solutions are possible, leading experimentally to a -15 percent delay reduction for a ring-oscillator of 1-gate finger inverters at 0.8V supply voltage. Secondly, we demonstrate the benefits induced by smart design layouts, enabled by process integration goodies and some layout constructs. Namely, a continuous-RX design, which consists in a long active line configuration, optimizes the stress configuration, maintaining a high level of longitudinal compressive stress, while relaxing the transverse one. A 28 percent ring oscillator delay improvement is experimentally demonstrated at a given leakage for 1-finger inverter at 0.8V supply voltage. This demonstrates the interest of process/design co-optimization of strain-induced layout effects. Finally, we discuss the technological knobs and especially the strain boosters that can furthers the scaling of FDSOI below the 14nm node: SiGe channel and source/drain of high-Ge content, influence of the surface orientation and channel direction, as well as the gate last integration.