bluuebunny/crossref_metadata_2025 huggingface dataset:
Adverse Effects of First‐Degree AV‐Block in Patients with Sinus Node Dysfunction: Data from the Mode Selection Trial
Authors: HOLMQVIST FREDRIK , HELLKAMP ANNE S. , LEE KERRY L. , LAMAS GERVASIO A. , DAUBERT JAMES P.
Published: May 2014

Background

Patients with a pacing indication and first‐degree atrioventricular (AV)‐block pose a clinical challenge. The prognostic impact of first‐degree AV‐block in patients with sinus node dysfunction and the impact of pacing in this setting are not known.

Methods

In the Mode Selection Trial (MOST), 2,010 patients with sinus node dysfunction were randomized to either dual‐chamber (DDD‐R) or ventricular (VVI‐R) pacing and followed for a median of 33 months. We report on clinical outcomes in patients with first‐degree AV‐block (PR interval > 200 ms) compared with patients who had a normal PR interval at baseline.

Results

Patients with first‐degree AV‐block (n = 378) were older (median [Q1, Q3]; 76 [70, 82] years vs 73 [66, 79] years, P< 0.0001), more often male (57% vs 49%, P = 0.0049), and had more comorbidity, such as hypertension (66% vs 60%, P = 0.034) and heart failure (24% vs 17%, P = 0.0050) than patients with normal AV‐conduction (n = 1,159). In multivariable analyses, patients with first‐degree AV‐block were at greater risk of death, stroke, or heart failure hospitalization (hazard ratio [HR] 1.31, 95% confidence interval [CI] 1.06–1.61, P = 0.013). A trend towards a higher incidence of atrial fibrillation was seen (HR 1.24, 95% CI 0.98–1.55, P = 0.069). No significant interactions between pacing arm and prolonged versus normal PR were found for any endpoint, and hazard ratios were consistent across subgroups.

Conclusions

First‐degree AV‐block is associated with more advanced disease but is still an independent predictor of poor clinical outcome. Neither DDD‐R nor VVI‐R pacing, as employed in MOST, eliminate the negative effects associated with first‐degree AV‐block.
Azospirillum brasilense ameliorates the response of Arabidopsis thaliana to drought mainly via enhancement of ABA levels
Authors: Cohen Ana C. , Bottini Rubén , Pontin Mariela , Berli Federico J. , Moreno Daniela , Boccanlandro Hernán , Travaglia Claudia N. , Piccoli Patricia N.
Published: May 2014

Production of phytohormones is one of the main mechanisms to explain the beneficial effects of plant growth‐promoting rhizobacteria (PGPR) such as Azospirillum sp. The PGPRs induce plant growth and development, and reduce stress susceptibility. However, little is known regarding the stress‐related phytohormone abscisic acid (ABA) produced by bacteria. We investigated the effects of Azospirillum brasilense Sp 245 strain on Arabidopsis thaliana Col‐0 and aba2‐1 mutant plants, evaluating the morphophysiological and biochemical responses when watered and in drought. We used an in vitro‐grown system to study changes in the root volume and architecture after inoculation with Azospirillum in Arabidopsis wild‐type Col‐0 and on the mutant aba2‐1, during early growth. To examine Arabidopsis development and reproductive success as affected by the bacteria, ABA and drought, a pot experiment using Arabidopsis Col‐0 plants was also carried out. Azospirillum brasilense augmented plant biomass, altered root architecture by increasing lateral roots number, stimulated photosynthetic and photoprotective pigments and retarded water loss in correlation with incremented ABA levels. As well, inoculation improved plants seed yield, plants survival, proline levels and relative leaf water content; it also decreased stomatal conductance, malondialdehyde and relative soil water content in plants submitted to drought. Arabidopsis inoculation with A. brasilense improved plants performance, especially in drought.
Impact of a change in antibacterial prophylaxis on bacteremia and hospitalization rates following outpatient autologous peripheral blood stem cell transplantation for multiple myeloma
Authors: Kim J.H. , Goulston C. , Zangari M. , Tricot G. , Boyer M.W. , Hanson K.E.
Published: May 2014

Background

Levofloxacin is routinely used for the prevention of invasive bacterial infections during autologous peripheral blood stem cell transplantation (APBSCT). However, increasing rates of bacterial sepsis were noted at our institution among multiple myeloma (MM) patients undergoing outpatient APBSCT with melphalan‐based chemotherapy and levofloxacin prophylaxis. We assessed the impact of a change in antibacterial prophylaxis from oral levofloxacin (Period 1) to sequential oral levofloxacin followed by ertapenem (Period 2).

Methods

Electronic medical records were reviewed to identify MM patients who underwent APBSCT in the outpatient clinic between October 2007 and April 2012.

Results

Over a 4.5‐year period, 165 outpatient APBSCTs were eligible for the analysis. Fewer overall bacteremias occurred during Period 2 as compared with Period 1 (0.5 cases per 100 person‐days vs. 2.4 cases per 100 person‐days, P < 0.001). In addition, fewer patients were hospitalized for neutropenic fever while receiving sequential prophylaxis (45.7% vs. 75.7% of outpatient APBSCT recipients during Periods 2 and 1, respectively; P < 0.001). In Kaplan–Meier analysis, receipt of sequential prophylaxis (Period 2) was significantly associated with overall bacteremia‐free survival within 30 days after the APBSCT (P < 0.001). No significant differences were seen in the number of patients developing Clostridium difficile infection or ertapenem‐resistant gram‐negative bacteremia between study periods.

Conclusion

In conclusion, sequential prophylaxis may effectively prevent episodes of bacteremia and hospitalizations in neutropenic MM outpatient APBSCT recipients. Prospective studies that involve larger numbers of MM patients with extended periods of follow‐up are ultimately required to define the safety and efficacy of sequential antibacterial prophylaxis.
Use of episcleral cyclosporine implants in dogs with keratoconjunctivitis sicca: pilot study
Authors: Barachetti Laura , Rampazzo Antonella , Mortellaro Carlo M. , Scevola Stefania , Gilger Brian C.
Published: May 2014

Purpose

To describe the use, tolerability, and efficacy of episcleral silicone matrix cyclosporine (ESMC) implants in dogs with keratoconjunctivitis sicca (KCS).

Methods

Retrospective study.ESMCimplants (1.9 cm length, 30% wt/wtCsAin silicone; with approximately 12 mg ofCsAloaded into them) were used in dogs withKCSresponsive to topicalCsA(good candidate,GC) or not responsive (poor candidate,PC). Ocular surface inflammation scores, Schirmer tear test (STT) values, and ocular discharge quantity were evaluated and compared.

Results

Twenty‐seven eyes (15 dogs) received anESMCimplant forKCS; 15 eyes were consideredGC, and 12 were consideredPC. BothGCeyes andPCeyes showed a significant increase inSTTvalues (increase of 7.7 and 8.5 mm/min;P = 0.023 andP = 0.003, respectively) after placement ofESMCimplants (mean follow‐up 18 ± 2 and 10.4 ± 15 months, respectively). Clinical signs improved significantly in both groups during the same follow‐up, with reduction in conjunctival hyperemia (P < 0.001), corneal neovascularization (P = 0.004), corneal opacity (P = 0.003), and ocular discharge (P = 0.002).ESMCimplants were well tolerated by all dogs, but two eyes lost the device at 12‐months and 1‐week follow‐up, respectively.

Conclusions

Results from this study suggest that theEMSCimplants were well tolerated and efficacious in dogs withKCSresponsive to topicalCsAas well as dogs with poor response to topical therapy. Further study is needed to determine the duration of efficacy and optimal dose ofCsA.
Tuberculosis and TNF-inhibitors: history of exposure should outweigh investigations
Authors: Reichmann Michaela T , Marshall Ben G , Cummings Fraser , Elkington Paul T
Published: May 2014

A 39-year-old Indian man was diagnosed with ulcerative colitis on colonic biopsy and started on mesalazine, prednisolone and azathioprine. However, the colitis remained active and required antitumour necrosis factor (TNF) treatment with infliximab. Prior to starting infliximab, his chest X-ray was normal and QuantiFERON interferon γ release assay for tuberculosis (TB) was negative. However, his wife had been treated for pulmonary TB 11 years previously when they were cohabiting. On attending for his third dose of infliximab, he was feverish and tachycardic, and was admitted for investigation. Chest X-ray on admission showed changes consistent with miliary TB, and thoracic CT confirmed extensive miliary nodules with supraclavicular and mediastinal lymphadenopathy. Abdominal CT showed multiple mesenteric lymph nodes. Subsequent bronchoalveolar lavage, neck lymph node aspirate and colonic biopsies all culturedMycobacterium tuberculosis. In retrospect, a clear history of close household TB exposure should have precipitated consideration of TB chemoprophylaxis prior to anti-TNF treatment.
Congenital ductus arteriosus aneurysm: an unusual cause of transient neonatal hypertension
Authors: Murki Srinivas , Deshbhatla Sai Kiran , Sharma Deepak , Rao Nageshwar , Verma Sudeep
Published: May 2014

Case 1: A term male child was re-admitted on day 10 of life due to acute onset of respiratory distress. Physical examination revealed tachypnoea, tachycardia and blood pressure (BP) above the 95th centile in all four limbs. Cardiovascular examination revealed a short systolic murmur on the sternal border. Abdomen showed hepatomegaly of 3 cm below the costal margin. Chest X-ray showed a cardiothoracic ratio of 0.65 with normal vascularity. Ultrasound and Doppler of the kidneys and brain were normal. The high parasternal view showed a large ductus arteriosus aneurysm (DAA) of 2.0×2.5 cm. The baby was managed with inotropes and antihypertensives. CT angiogram showed 1.6×0.6 cm thrombosed DAA, which was extending from the posterior descending aorta to the ampulla. With the resolution of aneurysm BPs normalised and antihypertensives were stopped at 6 weeks of age.Case 2: A premature male neonate weighing 1.2 kg was admitted to the neonatal intensive care unit for respiratory distress syndrome. On the 4th day of life during routine measurement of vitals, the BP was consistently above 95th centile in all four limbs. Blood tests revealed thrombocytopenia that persisted inspite of single donor transfusions. The evaluation for sepsis was negative. The ultrasound and Dopplers of the kidneys and brain were all normal. A transthoracic echocardiogram showed a large DAA measuring 5×1.8 mm. Hypertension was managed with antihypertensives. Serial transthoracic echocardiogram showed organising DAA. CT angiogram showed 6 mm×2 mm thrombosed DAA. As the arterial BP normalised, antihypertensives were stopped on day 15 of life. The baby was discharged on day 29 of life and on follow-up BP remained normal.
Conservative management of bilateral choanal atresia? Bilateral choanal atresia diagnosed in a 5-year-old girl
Authors: Cadd Brandon , Talwar Rishi , Bajaj Yogesh
Published: May 2014

Choanal atresia (CA) is an obliteration or blockage of the posterior nasal aperture, limiting or obstructing the nasal airway to the nasopharynx. The presentation of unilateral CA commonly occurs at a later age than those children affected by bilateral CA (BCA) and can often persist undiagnosed into adulthood. BCA, on the other hand, typically presents with respiratory obstruction within the first few days of life, or desaturations with or without cyanosis when feeding or during exertion and traditional teaching is that this is a life-threatening emergency. We present the case of a 5-year-old girl referred to our department with nasal obstruction, snoring and some mild rhinorrhoea. After investigation she was found to have a mixed bony and membranous BCA and no other craniofacial abnormalities. The BCA was subsequently repaired using urethral dilators and a drill and the child is currently asymptomatic of any restenosis. This case prompts discussion of the various presentations and options in management of CA as well as allowing us an opportunity to discuss the literature on the subject.
Cold-water immersion and iced-slush ingestion are effective at cooling firefighters following a simulated search and rescue task in a hot environment
Authors: Walker Anthony , Driller Matthew , Brearley Matt , Argus Christos , Rattray Ben
Published: May 2014

Firefighters are exposed to hot environments, which results in elevated core temperatures. Rapidly reducing core temperatures will likely increase safety as firefighters are redeployed to subsequent operational tasks. This study investigated the effectiveness of cold-water immersion (CWI) and iced-slush ingestion (SLUSH) to cool firefighters post-incident. Seventy-four Australian firefighters (mean ± SD age: 38.9 ± 9.0 years) undertook a simulated search and rescue task in a heat chamber (105 ± 5 °C). Testing involved two 20-min work cycles separated by a 10-min rest period. Ambient temperature during recovery periods was 19.3 ± 2.7 °C. Participants were randomly assigned one of three 15-min cooling protocols: (i) CWI, 15 °C to umbilicus; (ii) SLUSH, 7 g·kg−1 body weight; or (iii) seated rest (CONT). Core temperature and strength were measured pre- and postsimulation and directly after cooling. Mean temperatures for all groups reached 38.9 ± 0.9 °C at the conclusion of the second work task. Both CWI and SLUSH delivered cooling rates in excess of CONT (0.093 and 0.092 compared with 0.058 °C·min−1) and reduced temperatures to baseline measurements within the 15-min cooling period. Grip strength was not negatively impacted by either SLUSH or CONT. CWI and SLUSH provide evidence-based alternatives to passive recovery and forearm immersion protocols currently adopted by many fire services. To maximise the likelihood of adoption, we recommend SLUSH ingestion as a practical and effective cooling strategy for post-incident cooling of firefighters in temperate regions.
On the mathematical theory of post-Darwinian mutations, selection, and evolution
Authors: De Angelis E.
Published: May 2014

This paper is devoted to the modeling, qualitative analysis and simulation of Darwinian selection phenomena and their evolution. The approach takes advantage of the mathematical tools of the kinetic theory of active particles which are applied to describe the selective dynamics of evolution processes. The first part of the paper focuses on a mathematical theory that has been developed to describe mutations and selection processes. The second part deals with different modeling strategies and looks ahead to research perspectives.
URINE FLOW DYNAMICS THROUGH THE URETHRA IN PATIENTS WITH BLADDER OUTLET OBSTRUCTION
Authors: ISHII TAKURO , NAYA YUKIO , YAMANISHI TOMONORI , IGARASHI TATSUO
Published: May 2014

Voiding dysfunction is a common disease among the elderly male population. However, few studies have elucidated the flow dynamics of the disease mechanism. We attempted to clarify the fluid dynamics of urine in the prostatic urethra (PU) in patients with bladder outlet obstruction (BOO), a common disease associated with voiding dysfunction. A model of normal PU and three phase models following the BOO progression were prepared using 3D CAD software tracing cystourethroscopic images. In fluid dynamics computation, the normal detrusor pressure was applied to the bladder side in each model. Results of fluid simulation were compared for flow trajectory line, fluid energy dynamics using Bernoulli's principle and pressure loss coefficient. In the BOO model, a large vortex was observed adjacent to the bladder outlet (BO) with increased hydraulic energy loss during the passage through the tract. In contrast, opening of the BO eliminated the vortex with reduction of hydraulic energy loss. These results corresponded with clinical data measured by catheterized pressure sensors inserted into the urethra, and those of urethral diameter measured by urethrography. Fluid dynamics simulation using CAD models can clarify the mechanism of voiding dysfunction in a less invasive and more acceptable way in patients with BOO.
Fluorescence properties of full-color-emitting BCNO phosphors synthesized under different oxygen pressure
Authors: Zhang Feng , Zhang Weifeng , Li Guoqiang , Wang Yachun , Yuan Hua
Published: May 2014

The colorful BCNO phosphors comprised of boron, carbon, nitrogen, and oxygen atoms have been novelty synthesized by varying the environmental oxygen pressure without changing the compositions of the raw materials such as boric, urea, and poly-ethylene glycol. X-ray diffraction (XRD), fourier-transformed infrared (FTIR), and photoluminescence (PL) spectra were employed to characterize the effect of environmental oxygen pressure on the structure and PL properties of the synthesized phosphors. The results of their PL properties indicates that the emission color of these BCNO phosphors has been easily tailored for a large-range from violet to near-red regions through variations of the environmental oxygen pressure as prepared under the excitation of 365 nm. This provides a new approach to tailor the emitting colors.
(Invited) Impact of Surface Chemistry on the Electrochemical Performance of Perovskite Cathodes
Authors: Backhaus-Ricoult Monika , Work Kimberley , Adib Kaveh , Gregoratti Luca , Amati Matteo
Published: May 2014

Surface chemistry and reactivity of electrodes in electrochemical devices play a key role for electrochemical performance and cell durability. In this work, we use spatially resolved scanning photoelectron microscopy and electrochemical measurements to study in situ the surface chemistry of perovskite catalysts in SOFC cathode model cells during high temperature operation at 500-550°C in oxygen containing environment (10-6mbar) at OCV or under oxygen flux. Oxygen ion flux and electric field cause dynamic changes of catalyst and electrolyte surface chemistry, including redox reaction, surface segregation and long range surface diffusion. In LSM cathodes, oxidizing environment was found to promote transition metal-rich cathode surface termination with high surface oxygen content and a variety of oxygen surface species, while reducing environment produced surface segregation of strontium and low level of surface oxygen. The electrochemical response provided the rate-determining reaction steps of the operating model cell and could directly be compared to the spectroscopic observations.
(Invited) Impact of Size Scale on Electro-Chemo-Mechanical Coupling Properties in MIECs: Bulk and Thin Film (Pr,Ce)O2-δ
Authors: Bishop Sean R. , Chen Di , Sheth Jay , Misture Scott , Sheldon Brian W. , Kim Jae Jin , Tuller Harry L.
Published: May 2014

The point defect induced strain and stress in thin films was analyzed using in situ wafer curvature and in-situ XRD measurements. The strains and stresses were modeled using a previously well-developed and experimentally validated point defect equilibria model. Values for the chemical expansion coefficient and Young’s modulus for bulk ceramics were successfully used to predict stress and strain behavior of the corresponding thin films.
Influence of Surface/Interface on the Performance of MIEC Cathode for SOFC
Authors: Sato Hiroki , Yashiro Keiji , Sasaki Mie , Hashimoto Shin-ichi , Nakamura Takashi , Amezawa Koji , Kawada Tatsuya
Published: May 2014

La0.6Sr0.4CoO3 (LSC40) has been studied as an SOFC cathode. It is reported that the oxygen reduction reaction was enhanced at hetero-interface of LSC40 and La1.5Sr0.5CoO4 (LSC155). Relationship between the electrode performance and the surface chemistry was elucidated to find out the mechanism of the hetero-interface effect. Thin film electrodes of LSC40, LSC155, and double-layer electrode of LSC155-on-LSC40 were fabricated by pulsed laser deposition. The electrode performance was measured by impedance measurement. LSC40 electrode degraded during the measurement, and enrichment of strontium was observed at the surface of the degraded LSC40 by EDX analysis. On the other hand, the segregation of strontium was suppressed on the double-layer electrode, whose electrode performance was relatively higher than that of LSC40 single-phase electrode. It implies that the layered LSC155 may suppress the electrode degradation.
(Invited) In Situ Optical and Electrochemical Studies of SOFC Carbon Tolerance
Authors: Reeping Kyle W. , Halat David M. , Kirtley John D. , McIntyre Melissa D. , Walker Robert A.
Published: May 2014

Correlating real time, in situ spectroscopic observations with electrochemical performance provides insight into the ability of solid oxide fuel cells (SOFCs) to function sustainably despite adverse operating conditions. Experiments described in this work monitored the performance of SOFCs constructed with two different electrolyte materials: 8% yttria stabilized zirconia (YSZ) and 10% scandia stabilized zirconia (ScSZ). Both types of SOFCs were operated with CH4 as a fuel and carbon accumulation was monitored by in situ vibrational Raman scattering. SOFC performance was characterized using both linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Data showed that despite the more favorable conductivity properties of ScSZ, neither the rate nor the type of carbon formed is affected by electrolyte composition.
Improved Grain Boundary Conductivity By Post Annealing: Minimizing Vacancy Depletion through Non-Equilibrium Distribution of Immobile Species
Authors: Zhang Lei , Zhu Liangzhu , Liu Feng , Virkar Anil V.
Published: May 2014

A one dimensional model has been used to study the thermodynamics of defects in ionic crystals. It is found that space charge layer near grain boundary contributes to grain boundary resistance. Quenching less mobile ions to a distribution equilibrated at higher annealing temperatures increases point defect concentrations, which leads to a smaller grain boundary resistance. EIS measurement confirmed the model, and it is found that post annealing at higher temperatures helps to improve ionic transport through grain boundary.
New Approach of Data Mining from the Complex Impedance Plane: Parameters You Have Always Wanted to Have
Authors: Macak Jan M. , Patil Deepak , Fraenkl Max , Zima Vitezslav , Shimakawa Koichi , Wagner Tomas
Published: May 2014

We report on the new data mining approach based on Random walk theory. Through the full analysis of complex impedance spectra including electrode polarization effect, we derived the number of moving ions and the diffusion coefficient. These useful numbers were extracted without using an equivalent electric circuit. Our approach has the potential to find a widespread use in various electrochemical fields, such as in batteries, solar cells, fuel cells and semiconductor industry in general. In this paper, we show results for a case example of an ionic conductor – Ag-doped chalcogenide glass. However, this approach can be exploited for any semiconducting or ionic conductor materials, either in amorphous or crystalline form.
Modeling Power Production in a Tubular Carbon Fuel Cell
Authors: Johnson David U. , Mitchell Reginald E. , Gür Turgut M.
Published: May 2014

Carbon fuel cells (CFCs) offer promising technological opportunities for efficient and clean conversion of carbonaceous fuel (coal, biomass, waste, etc.) into electricity. In this study, we report the results of a finite-element model used to predict the performance of a solid oxide-based tubular air carbon fuel cell (ACFC). The comprehensive model couples mass and energy transport with electrochemistry and ion transport, and uses experimentally derived parameters to simulate anode and cathode kinetics as well as carbon bed chemistry. The model is used to map out power density and cell efficiency as a function of bed height, tube spacing and cell voltage. The model results can be used to aid design and operational decisions. As expected, calculations of ACFC performance indicate the typical tradeoff between power density and cell efficiency under both varying geometry as well as varying cell voltage. Calculated results demonstrate that a power density of 170 mW/cm2 can be attained with a cell efficiency in excess of 50%.
The Role of Nonstoichiometry on the Electrocatalytic Properties of TiO2-δ towards the Conversion of Carbon Dioxide to Fuels
Authors: Sharma Pranav P. , Ke Fu-Sheng , Zhou Xiao-Dong
Published: May 2014

Crystalline titanium oxide (TiO2) exhibits unique photocatalytic, optical, and electrical properties largely due to its three ubiquitous phases (e.g. rutile, anatase and brookite) and a wide range of nonstoichiometry. It is known that reduced titanium dioxides (TiO2-x and TiO) are active towards water oxidation. In this presentation, we will report our recent studies of using TiO2-x and TiO as the electrocatalysts to convert carbon dioxide to fuels by incorporating the electrocatalysts into a proton conducting membrane based full electrochemical cell. Nonstoichiometric Ti3O5 is prepared by reducing TiO2 at 900°C in hydrogen environment at ambient pressure. Ti3O5 is observed to exhibit a much higher Faradaic efficiency towards the formation of CO and formate, in comparison to both TiO and TiO2.
Charge Trapping Characterization of LaLuO3/p-Si Interfaces at Cryogenic Temperatures
Authors: Tyagulskyy Igor Petrovitch , Tiagulskyi Stanislav Igorovitch , Nazarov Aleksey Nickolaevitch , Lysenko Vladimir Sergeevitch , Hurley P. K. , Cherkaoui K. , Monaghan S.
Published: May 2014

The paper focuses on the experimental investigation of charge trapping and emission from shallow traps in the transition layer of the LaLuO3/p-Si structures in the temperature range 6-40K. The techniques of thermally activated charge release, isothermal transient emission currents were used to characterize shallow holetraps. Activation energies and densities of shallow hole traps have been determined.
(Invited) Replacement Metal Gate/High-k Last Technology for Aggressively Scaled Planar and FinFET-Based Devices
Authors: Veloso Anabela , Lee Jae Woo , Simoen Eddy , Ragnarsson Lars-Åke , Arimura Hiroaki , Cho Moon Ju , Boccardi Guillaume , Thean Aaron , Horiguchi Naoto
Published: May 2014

This work reports on aggressively scaled replacement metal gate, high-k last (RMG-HKL) planar and FinFET-based devices using a novel effective work function (EWF) engineering approach which relies on controlled diffusion mechanisms in the gate stack and enables wide VT modulation [>500 mV ΔVT in narrow-fin (WFin≥5 nm), triple-gate FinFETs], with no EOT nor JG penalty, improved mobility and reliability, excellent mismatch performance, up to ~6.3× reduced noise, and minimized parasitic gate resistance. Additionally, we present a thorough evaluation of the impact of post high-k deposition thermal (PDA) and plasma (SF6) treatments for planar vs. FinFET devices with different Si crystal orientations, providing a deeper insight into underlying degradation mechanisms. SF6 enables improved mobility and reduced interface trapped charge density (Nit), helping to mitigate the impact of fin patterning and fin sidewall crystal orientations, while allowing a simplified dual-EWF metal CMOS scheme suitable for both device architectures. PDA results in substantially improved reliability behavior due to bulk defects reduction.
(Invited) Charge Trapping Type SOI-FinFET Flash Memory
Authors: Liu Yongxun , Nabatame T , Matsukawa T , Endo K , O'uchi S , Tsukada J , Yamauchi H , Ishikawa Y , Mizubayashi W , Morita Y , Migita S , Ota H , Chikyow T , Masahara M
Published: May 2014

The charge trapping (CT) type tri-gate (TG) silicon on insulator (SOI) FinFET flash memories with different gate and blocking layer materials have successfully been fabricated, and their electrical characteristics including short-channel effect (SCE) immunity, threshold voltage (Vt) variability and memory property have comparatively been investigated. It was experimentally found that a large memory window is obtained in the physical vapor deposited (PVD) titanium nitride (TiN) metal gate flash memories than the n+-poly-Si gate ones owing to the higher work function of PVD-TiN metal gate, which is effective to suppress electron back tunneling during erase operation. It was also confirmed that the better SCE immunity and a significant improvement in memory window are observed by introducing a high-k Al2O3 blocking layer into the PVD-TiN metal gate flash memories. Moreover, it was found that the Vt variations before and after a program/erase (P/E) cycle are independent of the gate and blocking layer materials.
(Invited) Sputtered Metal Oxide Broken Gap Junctions
Authors: Campbell Stephen , Johnson Forrest , Karthikeyan Sreejith , Song Sang-Ho , Liptak Richard , Benton Brian
Published: May 2014

Broken gap metal oxide tunnel junctions have been created by sputtering. Using a ceramic ZnO-SnO2 target and a reactively sputtered copper target we deposited ZnSnO3 and Cu2O for the n-type and p-type layers, respectively. AlCuO2 can also be used for the p-type layer. It shows better thermal uniformity and improved optical transmittance, but somewhat higher specific junction resistance. The band structure of the respective materials have theoretical work functions which line up with the band structure for a tandem solar cell and quantum dot LED applications. As-deposited films demonstrated a dependence of the I-V profile with post-deposition rapid thermal anneal. Total junction specific contact resistances under 1 ohm-cm2 have been achieved.
Raman Characterization of Poly-Si Channel Materials for 3D Flash Memory Device Applications
Authors: Yoo Woo Sik , Ishigaki Toshikazu , Ueda Takeshi , Kang Kitaek , Sheen Dong Sun , Kim Sung Soon , Ko Min Sung , Shin Wan Sup , Kwak Noh Yeal , Lee Byung Seok
Published: May 2014

For poly Si channel applications used in three-dimensional (3D) flash memory devices, amorphous Si films deposited on thin SiO2 on Si wafers were converted to poly Si by solid-phase crystallization in the temperature range of 600 ~ 1050oC under Ar, N2 and forming gas (N2 96% + H2 4%) ambients. Annealing temperature and process ambient gas dependence of the poly conversion process was studied. The degree of amorphous to poly conversion and grain size distribution of poly Si were investigated using Raman spectroscopy. Six different Raman excitation wavelengths, with different probing depths, were tested to observe the uniformity of amorphous to poly Si conversion in the depth direction. No significant excitation wavelength dependence of the Raman spectra was observed from the converted poly Si, implying fairy homogeneous conversion throughout the thickness of film.
(Invited) Challenges in Contact Technologies for Planar/Non-Planar Si Technologies
Authors: Adusumilli Praneet , Alptekin Emre , Breil Nicolas
Published: May 2014

This article explores challenges to fabricating contacts to CMOS devices as the industry transitions from planar to non-planar device geometries. Traditional challenges such as contacted gate pitch scaling, parasitic capacitance & resistance as well as newer challenges due to an increase in process & integration complexity are reviewed and highlighted.
(Invited) Significant Enhancement of High-Ns
Electron Mobility in Ge n-MOSFETs with Atomically Flat Ge/GeO2 Interface
Authors: Lee Choonghyun , Nishimura Tomonori , Lu Cimang , Zhang Wenfeng , Nagashio Kosuke , Toriumi Akira
Published: May 2014

The rapid degradation of high-Ns
electron mobility in Ge n-MOSFETs is still one of the greatest concerns in Ge CMOS technology. Although there are many possible origins so far considered, the degradation mechanism is still unclear in spite of its importance. In this work, we clarify wafer-related origins for electron mobility degradation in Ge n-MOSFETs. High-Ns
electron mobility is dramatically improved thanks to (i) atomically flat Ge surface formation, followed by (ii) layer-by-layer oxidation. (iii) Oxygen-related neutral impurities in Ge substrates could be another origin of the mobility reduction on Ge wafers. By successfully eliminating these scattering sources in Ge n-MOSFETs, we demonstrate intrinsically high electron mobility in a wide range of Ns
.
(Invited) Thin Film Technologies for Micro/Nano Systems; A Review
Authors: van Zeijl Henk W.
Published: May 2014

The role of thin films in the manufacturing of physical and chemical sensors, actuators, microelectronics and large area electronics is reviewed. Either structural or sacrificial; thin films plays a key role in defining the critical dimensions in a micro system. For structural films, the device performance is to a greater extend determined by the film properties. New film properties enables new devices. The drive to further miniaturize micro/nano systems will further broaden the applications and push the technology of thin films.
Precise Chemistry Control Using Cyclic Stripping Voltammetry for Improved through Silicon via Fill
Authors: Shen Hong , Uzoh Cyprian , Dinan Thomas
Published: May 2014

This paper discusses using cyclic stripping voltammetry (CVS) and cyclic pulse stripping voltammetry (CPVS) to control a TSV via fill chemistry. With the tight process window of this specific chemistry, a slight imbalance of the additive results in a shift of the via fill from a complete bottom up fill to a complete conformal fill. This requires an accurate correlation of the CVS responses for process control and reproducibility.
High Sensitivity, Positive Tone, Low-k Polynorbornene Dielectrics
Authors: Mueller Brennen K , Schwartz Jared , Sutlief Alexandra , Kohl Paul A
Published: May 2014

A highly light sensitive, positive tone, low-k dielectric has been developed with excellent lithographic, mechanical, and electrical properties. The photolithographic solubility switching mechanism is based on well-studied, chemically amplified chemistry. The dielectric is composed of a polynorbornene backbone with pendent fluoroalcohol and tert-butyl ester functional groups. The effects of the photoacid generator and monomer ratio on lithographic, mechanical, and electrical properties are studied. The sensitivity (D100 = 8.09 mJ/cm2) and contrast (γ ≥ 14.2) are an order of magnitude higher than existing positive tone dielectrics. The dielectric can be cross-linked via a Fischer esterification after patterning. For one monomer composition (60% fluoroalcohol), the modulus and hardness were measured to be 2.99 GPa and 0.252 GPa, respectively. The dielectric constant for this composition was found to be 2.78.
(Invited) Simulation of GaN Device Reliability
Authors: Law Mark E , Patrick Erin , Horton David
Published: May 2014

TCAD has been a useful tool for device design for decades. Reliability of devices, particularly in novel technologies, like GaN/AlGaN HEMT’s is a problem that is not well supported by existing TCAD tools. This paper describes a reliability simulation capability and provides examples demonstrating its usefulness for investigation device failure.
(Invited) Large Area Semipolar GaN Grown on Foreign Substrates
Authors: Scholz Ferdinand , Caliebe Marian , Meisch Tobias , Alimoradi-Jazi Maryam , Klein Martin , Hocker Matthias , Neuschl Benjamin , Tischer Ingo , Thonke Klaus
Published: May 2014

By nucleation of GaN stripes on the c-plane-like side facets of trench-patterned sapphire wafers and their subsequent coalescence, we have realized various semipolar planar GaN layers by metalorganic vapor phase epitaxy. A variation of the miscut of r-plane sapphire wafers did not lead to improved (11-22) GaN layers despite the slight off-orientation between the GaN (11-22) plane and the sapphire r-plane. For (20-21) GaN grown on s-plane sapphire, we only obtained nicely coalesced layers after overgrowth by hydride vapor phase epitaxy (HVPE). However, increased parasitic oxygen incorporation was observed in HVPE growth of such semipolar layers. On the other hand, the Mg incorporation was reduced by about a factor of 8 on (11-22) planes as compared to the polar c-plane.
(Invited) Microstrucutural Characterizaton of Stressed AlGaN/GaN HEMT Devices
Authors: Holzworth Monta Ray , Whiting Patrick , Pearton Stephen J. , Lu L. , Kang Tsung-Sheng , Ren Fan , Patrick Erin , Law Mark E , Jones Kevin Scott
Published: May 2014

Defects produced from the application of electrical stress to AlGaN/GaN high electron mobility transistors were studied. The defects observed include micron-length cracking of the AlGaN and GaN layers, a reaction of the native oxide interfacial layer between the gate contact and AlGaN epilayer resulting in a band defect, and an electrochemical pitting reaction between the gate contact and AlGaN epilayer. These defects were characterized using a combination of surface etching chemical deprocessing, top-down scanning electron microscopy, and cross sectional transmission electron microscopy. The cracks in the AlGaN and GaN layers are shown to lengthen under application of electrical stress. The band defects appear to coincide with a large increase in gate leakage current associated with the critical voltage during electrical stressing. However, continued electrical stressing past the critical voltage results in pitting of the AlGaN epilayer under and near the gate contact. Simulations of the electric field lines from these pitted devices match the defect morphology across a range of different stress conditions and device structures and geometries.
Effect of Gamma Irradiation on DC Performance of Circular-Shaped AlGaN/GaN High Electron Mobility Transistors
Authors: Hwang Ya-Hsi , Hsieh Yueh-Ling , Lei L , Li Shun , Ren Fan , Pearton Stephen J. , Yadav Anupama , Schwarz Casey , Shatkhin Max , Wang L , Flitsiyan Elena , Chernyak Leonid , Baca Albert G , Allerman A , Sanchez Carlos A , Kravchenko I. I.
Published: May 2014

The effect of low dose gamma irradiation on DC performance of circular-shaped AlGaN/GaN high electron mobility transistors weas investigated. The drain saturation current (IDS) increased 11.44% after irradiation with a dose of 700 Gy. Sheet resistance (Rs) was measured from transfer line method and it decreased 3.6% after irradiation. By extracting the resistance between source and drain in the drain I-V curve and combining with TLM data, mobility was found to increase 34.53% after irradiation. The mobility increase may come from the donor-type defects or the strain relaxation effect. Gate lag measurement was also performed and 5% current dispersion was found after irradiation with the dose of 700 Gy, indicating there were more defects generated after irradiation.
Low Current Collapse and Low Leakage GaN MIS-HEMT Using AlN/SiN as Gate Dielectric and Passivation Layer
Authors: Liu Shih Chien , Wong Yuen-Yee , Lin Yueh-Chin , Chang Edward Yi
Published: May 2014

An effective passivation and gate insulator with low current collapse and improved dynamic ON-state resistance (R
ON) for GaN MIS-HEMT is demonstrated in this work. The structure of passivation and gate insulator is fabricated by 4-nm SiN as the first passivation layer and 1-nm AlN. The bilayer AlN/SiN structure integrates the advantages of SiN and AlN. SiN passivation has been proved to effectively reduce GaN surface states. AlN has high bandgap of ~6.2 eV which can suppress leakage current. Hence, the unfavorable effects such as trapping effect and leakage current which will induce current collapse and are effectively suppressed by using AlN/SiN bilayer thin film. A GaN MIS-HEMT with AlN/SiN passivation and gate dielectric exhibits improved I‒V characteristics, low leakage current, low current collapse, and improved dynamic R
ON at high quiescent drain bias of 100 V.
Analysis of V-Shaped Pits Originated from Threading Dislocation in III-Nitrides Compound for Light Emitting Diodes
Authors: Ok Yulho , Kim Sunwoon , Kim In , Cho Hyungkoun
Published: May 2014

In this paper, problems of v-shaped pits originated from threading dislocation that can occur during the fabrication of light emitting diode and ways to solve these problems were introduced. First of all the electrical properties were measured by observable point of a v-shaped pit, then a form of v-shaped pit was separated according to the electrical properties. We found a correlation between the electrical properties and the form of v-shaped pit. Furthermore we knew that the particular form of v-shaped pit led to a leakage current. Consequentially, the improvement of these leakage current from v-shaped pits was proposed.
Low Thermal Budget Au-Free Hf-Based Ohmic Contacts on InAlN/GaN Heterostructures
Authors: Liu Yi , Kyaw Lwin Min , Bera Milan Kumar , Singh Sarab Preet , Ngoo Yi Jie , Lo Guo Qiang , Chor Eng Fong
Published: May 2014

We report Au-free Hf/Al/Ta ohmic contacts on InAlN/GaN-on-Si with low contact resistance (Rc) of 0.59 Ω.mm and contact resistivity (ρc) of 6.7×10-6 Ω.cm2 achieved using a low annealing temperature (600 oC). The dominant carrier transport mechanism is found to be electron thermionic field emission, as revealed by current-voltage-temperature measurements. Hf/Al/Ta ohmic contacts possess good surface morphology and edge acuity, and have a smooth interface with InAlN/GaN. Based on SIMS studies, formation of HfN is believed to be the reason for the formation of ohmic contacts. Preliminary thermal aging test shows that Hf/Al/Ta contacts on InAlN/GaN are stable at 350 oC in air for more than 200 hours.
Influence of Al2O3 Gate Dielectric on Transistor Properties for IGZO Thin Film Transistor
Authors: Kurishima Kazunori , Nabatame Toshihide , Shimizu Maki , Aikawa Shinya , Tsukagoshi Kazuhito , Ohi Akihiko , Chikyo Toyohiro , Ogura Atsushi
Published: May 2014

In this paper we investigated transistor properties of indium-gallium-zinc oxide (IGZO) thin film transistors (TFT) with Al2O3/SiO2 dielectric. The saturation field-effect mobility (msat) of TFTs with Al2O3 decreased about 10 % irrespective of the Al2O3 thickness. Furthermore, the threshold voltage (Vth) value of TFT with Al2O3 shifts toward positive direction about 0.5 V. We found that the SiO2/Al2O3 stack structure contains fixed charge of about -1.1 × 1011 /cm2 and dipole moment of about 0.4 V at Al2O3/SiO2 interface, and negligible fixed charge in Al2O3 layer. These indicate that the origin of the msat degradation and positive Vth shift are dominantly due to the fixed charge at IGZO/Al2O3 interface and dipole moment at Al2O3/SiO2 interface, respectively.
(Invited) The Use of Graphene as a Solid State Diffusion Barrier
Authors: Morrow Wayne K , Gila Brent P , Pearton Stephen J.
Published: May 2014

In this study we tested the effectiveness of graphene as a solid state diffusion barrier for titanium, which forms a strong bond with graphene and copper, which is weakly bonded to graphene. E-beam deposited titanium films on silicon were annealed with and without graphene barrier layers to determine if graphene will prevent a titanium silicide layer from forming. In addition copper on silica was studied with a graphene barrier to determine if the graphene would prevent copper diffusion into the underlying substrate. For titanium, the graphene layer is sacrificial and prevents or inhibits silicide formation. In the case of copper, surface diffusion of copper clusters on graphene is the failure mechanism and not diffusion through the graphene barrier.
(Invited) Improving the Performance of Quantum Dot Light-Emitting Diodes through Nanoscale Engineering
Authors: Pietryga Jeffrey M. , Bae Wan Ki , Park Young-Shin , Robel Istvan , Klimov Victor I.
Published: May 2014

Despite tremendous progress since the first demonstration of QD-based light-emitting diodes (QD-LEDs) there is substantial room for improvement in performance, particularly at high current densities. Here we analyze the role of Auger recombination in the performance of QD-LEDs by conducting a systematic characterization of device performance in conjunction with time-resolved spectroscopic studies of photoexcited carriers directly within the device structure. We use a series of structurally engineered core/shell QDs that exhibit very similar single-exciton properties, but distinctly different rates of non-radiative Auger recombination to show that both QD-LED efficiency and the onset for efficiency roll-off are strongly influenced by Auger recombination. Finally, we demonstrate that device efficiency can be improved by either reducing Auger recombination rates, or by improving charge-injection balance, both of which can be accomplished through engineering of the QD structure.
(Invited) Advances in Silicon Nanophotonics
Authors: Franzó Giorgia , Irrera Alessia , Miritello Maria , Boninelli Simona , Iacona Fabio , Priolo Francesco
Published: May 2014

Silicon nanophotonics is emerging as an important platform for a variety of applications. While several Si photonic devices have been fabricated the main problem stands with an efficient silicon light source. In this manuscript we briefly review recent advances in the field focusing, as an example, to two main cases: silicon nanowires and photonic nanocavities.
Investigation of e-h Trapping Efficiency in Eu3+ Doped YPO4 Using VUV Spectroscopy
Authors: Wallace Maxwell K , Diaz Anthony L
Published: May 2014

Absorption of Vacuum Ultraviolet (VUV) radiation creates excited electron – hole (e – h) pairs in phosphors that can either be trapped by bulk defect states, surface defects, Ln3+ activators, or recombine by host emission. The fraction of e – h captured by Ln3+ is defined as the transfer efficiency, nt. Host – to – activator energy transfer efficiencies were determined for micro- and nano-crystalline Y1-xPO4:Eux
3+ (0.0025 < x < 0.10) using excitation and reflectance spectroscopy. For YBO3:Eu3+ nano – particles, more e – h pairs are lost to the surface relative to the corresponding micron particles. Our work on YPO4:Eu3+ nano – particles reveals a similar result. However, for both compounds, no conclusion could be made about the effect of particle size on the bulk transport of e – h pairs.
(Invited) 3D Packaging Technologies and Applications, Latest Challenges and Supply Chain Activities
Authors: Beica Rozalia , Buisson Thibault , Pizzagalli Amandine
Published: May 2014

Semiconductor industry, for more than four decades, has rigorously followed Moore's Law in scaling down the CMOS technologies. Although several new materials and processes are being developed to address the challenges of future technology nodes, in the coming years they will be limited with respect to functionalities that future devices will require. As a consequence a clear trend of moving from CMOS to package and system architecture can be observed. Three-dimensional (3D) technology using the well-known Through Silicon Via (TSV) interconnect is one the emerging solutions, considered today the most advanced technology, that could enable various heterogeneous integration. 3D Integration is not limited to the CMOS scaling in itself, it is rather based on bringing more functionalities by stacking different type of devices (Logic, Memory, Analog, MEMS, Passive components) while reducing the form factor of the packaging. This functional diversification is also known as More-than-Moore.
Integrated CMOS-MEMS Technology and Its Applications
Authors: Machida Katsuyuki , Konishi Toshifumi , Yamane Daisuke , Toshiyoshi Hiroshi , Masu Kazuya
Published: May 2014

The paper reports a feature and techniques to resolve requirements of integrated CMOS-MEMS technology. The multiphysics simulation platform for this technology has been developed to understand simultaneously both the mechanical and electrical behaviors of MEMS stacked on LSI. An equivalent circuit of a MEMS accelerometer has been developed with an electrical circuit simulator. We review the technology for CMOS-MEMS accelerometer with a wide detection range. Using the simulation platform above, we investigated the capacitive CMOS-MEMS sensor to a MEMS accelerometer implemented by the post-CMOS process onto CMOS circuit. As a result, it is confirmed that integrated CMOS-MEMS technology will shed light on a solution of More than Moore technical trends.