bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical work load factors and carpal tunnel syndrome: a population-based study
Authors: Shiri R , Miranda H , Heliövaara M , Viikari-Juntura E
Published: May 2009

Objective:

Carpal tunnel syndrome (CTS) is the most common nerve entrapment syndrome. Studies on selected occupational populations suggest an association of CTS with forceful repetitive work and vibration. Only few population-based studies have addressed the role of physical load factors in CTS. The aim of this study was to investigate the relations between exposures to a single or a combination of physical work load factors and CTS.

Methods:

The target population consisted of people aged 30 years or older residing in Finland during 2000–2001. Of the 7977 eligible subjects, 6254 (78.4%) were included in the study. Occupational physical load factors were assessed by interview and CTS by physical examination.

Results:

The prevalence of possible or probable CTS was 2.1% in men and 5.3% in women. Work tasks with vibrating tools (adjusted odds ratio (OR) 1.9, 95% CI 1.2 to 2.9) and handgrip with high forces (OR 1.7, 95% CI 1.2 to 2.5) were related to an increased prevalence of CTS. There werejoint effectsbetween work tasks requiring handgrip with high forces and the use of vibrating tools (adjusted OR 3.3, 95% CI 2.0 to 5.4), between forceful activities (handgrip with high forces or handling of loads) and repetitive movements of the hands (OR 2.1, 95% CI 1.5 to 2.9), and between repetitive movements of the hands and the use of vibrating tools (OR 2.8, 95% CI 1.6 to 4.8). Only exposure in the most recent job was associated with CTS.

Conclusions:

Work tasks demanding handgrip with high forces or the use of vibrating tools are associated with CTS. The association is stronger if these work tasks are accompanied by repetitive movements of the hand or wrist.
EFFICIENT ROUTING STRATEGY ON SCALE-FREE NETWORKS
Authors: YU GANG , WANG XIAN-PENG , LU HONG-TAO
Published: May 2009

With the development of information technology, networks become a crucial part in modern society. Therefore, the improvement in routing strategy of networks is of great importance and significance. For the purpose of improving the efficiency of network traffic, we propose a new routing strategy with two tunable parameters based on local information of network. In our strategy, we include the static information, node degree, and dynamic information, buffer queue length, to guide the selection of the next transmission node. Since the importing of buffer queue length information, packets can be distributed more evenly in the network, which can reduce the congestion possibility of network. In addition, for the sake of evaluation of a routing strategy, we propose four criterions to assess the performance of network. Based on the four criterions, we first compare the experimental results of our strategy with the original strategy only including node degree information and then give some insights of our new strategy according to the simulation results.
INTERACTING BOSONIC ATOMS WITH RANDOM POTENTIAL IN OPTICAL LATTICES
Authors: LIU WEI , ZHU JIAN-YANG
Published: May 2009

In this paper, we study the ultracold atoms in optical lattice with a weak random external potential by an extended Bose–Hubbard model. When the on-site interaction is strong enough, the model can be mapped to the XXZ model. Then the mean-field theory is applied and we get the zero- and finite-temperature phase diagrams in different optical parameters. The differences between the systems with and without disorder were found, and the Bose-glass phase may exist in the system with disorder.
A DEPLETION DETECTION ARCHITECTURE BASED ON MAGNETORESISTIVE SENSORS FOR BIOAPPLICATION
Authors: ZHENG FEIYAN , WANG HAOCAI , ZHANG LI
Published: May 2009

This paper presents a novel architecture for a bio-detection system to reuse magnetoresistive sensors and improve its repeatability. The architecture is composed of two fixed magnetoresistive sensors, a movable biochip, a microfluidic device and two current straps. On the action of a magnetic field gradient generated by current strap, functional magnetic particles pass along the channel. Some particles are bound by a special reaction to the biochip surface, and magnetoresistive sensors on the two ends measure the number of particles of original state and subsequencial state. The signal difference of two magnetoresistive sensors reflect the number of the depletion magnetic particles captured by the biochip.
FAILURE LIMIT INVESTIGATION FOR THE SPLINE AIDED SOLUTION TECHNIQUE
Authors: AL-OBAIDI HASSAN N. , MAHDI ALI S. , KADHEM WASAN J.
Published: May 2009

A formal investigation describing the failure limit of the spline aided solution technique has been carried out. The influence of spline width on trajectory assigning accuracy at different axial positions is discussed in detail. Additionally this influence has been investigated widely concerning the accuracy of aberration calculations for two different cases. In the first one, spline width was made variable for both trajectory and aberration calculations. The second one analyzed the case in which this width varies only for aberration determination. Results clearly show that spline width is the only parameter that affects calculations. Generally, the technique's accuracy is found to be proportional to the quadratic spline width and hence accurate results can be reached as long as the spline width is small.
PRESSURE EFFECTS ON Mg70Zn30 SUPERCONDUCTOR
Authors: VORA ADITYA M.
Published: May 2009

Theoretical computation of the pressure dependence of superconducting state parameters of binary Mg 70 Zn 30 is reported using model potential formalism. Explicit expressions have been derived for the volume dependence of the electron–phonon coupling strength λ and the Coulomb pseudopotential μ* considering the variation of Fermi momentum kF and Debye temperature θD with volume. The well-known Ashcroft's empty core (EMC) model pseudopotential and five different types of the local field correction functions viz. Hartree (H), Taylor (T), Ichimaru–Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) have been used for obtaining pressure dependence of transition temperature TC and the logarithmic volume derivative Φ of the effective interaction strength N0V for metallic glass. It has been observed that the μ* curve shows a linear nature and an elbow is formed in the Φ graph.
EFFECT OF TANTALUM ON FERROELECTRIC PHASE TRANSITION BEHAVIOR OF SrBi4Ti4O15 SINTERED DISCS
Authors: MADHAVI K. , KUMAR G. S. , PRASAD G.
Published: May 2009

Tantalum modified strontium bismuth titanate ceramic discs with general formula SrBi 4 Ti (4-5x) Ta 4x O 15 with x = 0, 0.1, 0.2 and 0.3 have been prepared through solid state reaction method. The samples are poled and dielectric constant, loss and AC conductivity measurements are done in the temperature region (30–600°C). Ta 5+ doping brought out interesting changes in dielectric phase transition behavior of the samples. Dielectric loss and conductivity measurements indicate the presence of charged defects. The results indicate changes in the distortion of the lattice. The distortion is calculated from the changes in the Curie temperature. AC conductivity results are understood in terms of the unoccupied sites and oxygen vacancies that are present in the samples.
THE COST OF ENVIRONMENTAL IMPACT ASSESSMENT (EIA) IN SOUTH AFRICA
Authors: RETIEF FRANCOIS , CHABALALA BENNETT
Published: May 2009

The wide adoption of EIA internationally is implicitly or explicitly based on the assumption that the benefits of EIA outweigh the costs. However, there has been surprisingly little empirical research conducted on the "cost" of EIA. The latter has been mostly because of the difficult methodological challenges it presents, which include the difficulties associated with clarifying terminology and disentangling what is meant by "cost". South Africa has been a leading developing country in terms of the introduction of EIA. However, almost a decade of mandatory EIA practice has raised serious questions about unjustified and unnecessary time delays and monetary costs and a desperate need for improved efficiency and effectiveness. In light of the latter the urgent need to gain a better understanding of the "cost" of EIA is evident. This paper presents preliminary results of an empirical study on the "direct EIA cost" in relation to "overall project cost" in South Africa. The data was obtained from a detailed survey of 148 EIAs conducted in the Free State, North West and the Northern Cape Provinces. The research suggests that the average direct cost of EIA within this region of South Africa is particularly low compared to international EIA systems. However, as a percentage of total project cost, EIA in South Africa compares with the higher spectrum of international practice. The latter suggests that within the South African context a large number of EIAs are being conducted for relatively small scale projects and that the main cost burden is placed on small and medium economic enterprise. In conclusion the overall profile of EIA cost in the South African context is described in relation to four broad project categories. To take the debate forward and to allow for regional comparative analysis, it is proposed that the research be expanded to include other provinces.
Lipid Signaling in Pathogenic Fungi
Authors: Rhome Ryan , Del Poeta Maurizio
Published: May 2009

Lipid signaling in pathogenic fungi has been studied to determine the role of these pathways in fungal biology and human infections. Owing to their unique nature, they may represent targets for future antifungal treatments. Farnesol signaling was characterized as a quorum-sensing molecule, with exposure inhibiting filamentation. Research has shown involvement in both the Ras1-adenylate cyclase and MAP kinase pathways. In species of Aspergillus, farnesol exposure induces apoptosis-like changes and alterations in ergosterol synthesis. Eicosanoid production has been characterized in several pathogenic fungi, utilizing host lipids in some cases. The role in virulence is not known yet, but it may involve modulation of host lipids. Sphingolipid signaling pathways seem to center around the production of diacylglycerol in the formation of inositol phosphorylceramide. Diacylglycerol activates both melanin production through laccase and transcription of antiphagocytic protein, both of which are involved in virulence.
'Core-shell' Cathode Materials for Lithium-ion Batteries Prepared via Mechanochemical Route
Authors: Kosova Nina V. , Devyatkina Evgeniya T. , Kaichev Vasily V. , Slobodyuk Arseny B.
Published: May 2009

Solid state mechanical activation method was applied for surface modification of LiCoO2 by simple oxides (Al2O3, TiO2, MgO and Li2O•2B2O3) and of LiMn2O4 by LiMO2 (M=Co, Ni). Pristine materials were ground with correspondent precursors and then heat treated at different temperatures. As prepared materials were studied by XRD, 6,7Li and 27Al MAS NMR spectroscopy, XPS, SEM and electrochemical tests. It has been shown that electrochemical properties of coated cathodes strongly depend on the composition and the thickness of coating layer.
Effect of Electrolyte Compositions on the Corrosion Behavior of Oxide Films on AZ91D Magnesium Alloy Prepared by Micro-Arc Oxidation
Authors: Ryu Hyun Sam , Hong Seong-Hyeon
Published: May 2009

In order to increase corrosion resistance, a protective ceramic films were prepared by micro-arc oxdiation (MAO) of AZ91D magnesium alloys (AZ91D)in an aluminate electrolyte containing potasium hydroxide, potassium fluoride, or sodium hydroxide, and the influence of theses electrolyte additives on corrosion behavior was elucidate.A porous films were formed, mainly consisting of MgAl2O4. The MAO films formed in KF-containing electrolyte consisted of porous outer layer and dense inner layer, but in KOH- or NaOH- electrolyte, no dense inner layer was extinctly observed. The corrosion resistance of MAO films was performed by EG&G potentiostat/galvanostat model 273 in 3.5 wt% NaCl solution, and the corrosion resistance of MAO films were found to be strongly dependent on electrolyte components. All MAO samples have thigher corrosion potential, lower corrosion density and higher polarization resistance than uncoated sample. Particullary, MAO films formed in KF-containing eletctrolyte exhibited a wide passivation region and the best corrosion resistance.
Corrosion Propagation Behavior of Magnesium Alloys under Atmospheric Conditions
Authors: Takigawa Shunsuke , Muto Izumi , Hara Nobuyoshi
Published: May 2009

To investigate corrosion mechanisms of magnesium alloys under atmospheric conditions, field exposure tests were performed. In a marine environment, magnesium alloys experienced localized corrosion, including pitting and filiform corrosion. To reproduce such actual atmospheric corrosion in a laboratory experiment, we employed a wet-dry cyclic test at a constant dew point. From the results of the wet-dry cyclic tests, the propagation mechanism of localized corrosion on magnesium alloys has been discussed. Localized corrosion occurred during the wetting period, and the corroded sites thus formed were repassivated during the drying period. In the next wetting period, new localized corrosion took place, but the repassivated sites were not reactivated. The repassivated sites have higher corrosion resistance than the non-corroded part of the surface because of the barrier effect of the corrosion products. In the case of AZ91D, Al enrichment in the surface region of the metal matrix is responsible for this corrosion resistance.
Effect of the Ammonia Nitrogen on Corrosion Behavior of Steel in 3.5% NaCl
Authors: Wang Xiutong , Hou Baorong
Published: May 2009

The land-sourced pollutants including industry wastewater and sewage bring to the coast zone sea pollution. The pollutants in the seawater can aggravate or reduce the corrosion of the steel. Among them the ammonia nitrogen is an important factor. In this paper the effect of the ammonia nitrogen on corrosion in 3.5% NaCl solution was discussed. Two types of steel were selected for the research. Scanning electron microscopy and electrochemical technology was used to investigate the effect.
Mn(IV) and Mn(III) Cycling in Microbiologically Influenced Corrosion
Authors: Strom Matthew J. , Dexter Stephen C.
Published: May 2009

The formation of biofilms on metal surfaces has been reported to cause sustainable increases in the corrosion currents. This is accomplished through the alteration of the surface chemistry upon biofilm formation. Many mechanisms have been proposed for this aspect of microbiologically influenced corrosion. One of these mechanisms is the cycling of manganese at the metals surface. This study identifies two reactions that take place as a result of biofilm formation. These reactions are indicative of the reduction of Mn(IV) to Mn(III) and the reduction of Mn(III) to Mn(II). Of these two reactions, the reduction of Mn(IV) to Mn(III) may be responsible for the previously reported sustainable increases in the cathodic current because of its persistence over multiple polarizations. The results also suggest that organic ligands, capable of stabilizing Mn(III) in the environment, may be present in marine biofilms of Delaware Bay.
Photoluminescence Quantum Efficiency of Self Assembled Germanium Nanocrystals
Authors: Lockwood David J. , Rowell Nelson , Berbezier Isabelle , Ronda Antoine
Published: May 2009

Germanium nanocrystals (NCs) were formed by in-situ thermal annealing of an amorphous Ge layer deposited by molecular beam epitaxy on a thin SiO2 layer on Si(001). The Ge NCs were then capped in situ with a thin layer of amorphous Si to prevent oxidation. For samples with average NC diameters ranging from 2.5 to 60 nm, the NC photoluminescence (PL) appeared primarily as a wide near-infrared band peaked near 800 meV. Using both the k•p and tight binding theoretical models, we have analyzed the PL spectrum in terms of the NC size distribution required to reproduce the observed asymmetric band shape, which includes, for the smaller diameter NCs, a band gap enlargement due to quantum confinement. The peak energy of the PL band reflects the average NC size and its shape depends on the NC size distribution. The observed size distribution determined from transmission electron microscopy analysis allowed the determination of the nonlinear increase in the PL quantum efficiency with decreasing NC diameter. Alternatively, given a good theoretical description of the system, it is thus possible to evaluate the size distribution of semiconductor NCs from their PL energy dependence.
Copper Decoration Combined with Preferential Etching for Delineation of Crystal Defects in SOI and sSOI Materials
Authors: Idrisi Hanan , Pejic Marijana , Uzelli Fatma , Kolbesen Bernd
Published: May 2009

Preferential etching with a dilute Secco etch is the routinely applied procedure for the delineation of crystal defects in Silicon-On-Insulator (SOI)- and strained Silicon-On-Insulator (sSOI)-materials. Its capability can be improved with a preceding copper decoration step. However, a shortcoming of copper decoration may be the formation of artefacts resulting in a deceptively high defect density. Optimized copper decoration conditions are presented. Furthermore, a combination of copper decoration with preferential etching was attempted to delineate all defect types in sSOI materials.
Ultra Compact FDSOI Transistors including Strain and Orientation: Processing and Performance
Authors: Fenouillet-Beranger Claire , Pham Nguyen Loan , Perreau Pierre , Denorme Stephane , Andrieu Francois , Faynot Olivier , Tosti Lucie , Brevard Laurent , Buj Christel , Weber Olivier , Gallon Claire , Fiori V. , Boeuf Frederic , Cristoloveanu S. , Skotnicki Thomas
Published: May 2009

The different ways to boost the devices performance, by using local strain approach and crystalline orientations, are investigated. We focus on the CESL (Contact Etch Stop Layer) induced mechanical stress and on the specific technological features of FDSOI (Fully-Depleted). The impact of device geometry, buried oxide layer (BOX) and elevated source/drain is studied by using finite element mechanical simulations. The significant amount of stress transferred to the channel, observed by mechanical simulation, has been validated by systematic measurements. An important mobility improvement has been achieved for short gate length which is a mandatory condition for advanced CMOS low-power applications.
Mechanisms that Explain Short-Channel Effects of Sub-50-nm-Channel Ultra-Thin Symmetric Double-Gate SOI MOSFET
Authors: Omura Yasuhisa , Tahara Yuki
Published: May 2009

Threshold voltage behaviors of the short-channel ultra thin symmetric double-gate (SDG) SOI MOSFET having a thin SOI body are simulated using the hydrodynamic transport model. We first propose models of threshold voltage and surface potential at the threshold that triggers the conventional drain-induced barrier lowering (DIBL) effect. From detailed analyses of device operations, it is demonstrated that the drain-induced potential rising (DIPR) effect at the middle of the SOI body plays an important role in determining the short-channel effects of SDG SOI MOSFET having a thin and low-doping body.
Gate Stack Influence on GIFBE in nFinFETs
Authors: Martino Joao A. , Rodrigues Michele , Mercha Abdelkarim , Simoen Eddy , Veloso Anabela , Collaert Nadine , Jurczak Malgorzata , Claeys Cor
Published: May 2009

The aim of this work is to study for the first time the gate induced floating body effect (GIFBE) of triple gate nFinFETs devices with different gate stack options for working function (WF) engineering. Based on electrical characterizations it is shown that the presence of a cap layer like Dy2O3 increases EOT and reduces the gate effective WF which decrease VFB and VT. As a consequence the transconductance also decreases and a positive shift of the onset of the GIFBE is observed both at room and at high temperature.
Analytical Modeling of Double Gate Graded-Channel SOI Transistors for Analog Applications
Authors: Ferreira Francisco A. , Cerdeira Antonio , Flandre Denis , Pavanello Marcelo
Published: May 2009

In this work we present the development of an analytical model for double gate (DG) Silicon-on-Insulator (SOI) nMOSFET transistor with graded-channel (GC), valid from weak inversion to strong inversion. Atlas numerical two-dimensional simulations and experimental results are used to validate the proposed model. Good agreement between simulated, modeled and experimental results is demonstrated.
Low-Temperature Measurements on Germanium-on-Insulator pMOSFETs: Evaluation of the Background Doping Level and Modeling of the Threshold Voltage Temperature Dependence
Authors: Van Den Daele William , Augendre Emmanuel , Romanjek Krunoslav , Le Royer Cyrille , Clavelier Laurent , Damlencourt Jean-Francois , Guiot Eric , Ghyselen Bruno , Cristoloveanu S.
Published: May 2009

Fully depleted GeOI (Germanium on Insulator) pMOSFETs with HfO2/TiN gate stack and Si-passivation are studied at low temperature. The impact of the starting Ge material and N-type channel doping on threshold voltage is examined. As there is no evidence of a background doping in Ge ﬁlms, the typical parasitic conduction and threshold voltage shift in p-channel GeOI MOSFETs are due to interface states. An extended model predicting the threshold voltage temperature dependence in GeOI transistors is proposed.
The Wave SOI MOSFET: A New Accuracy Transistor Layout to Improve Drain Current and Reduce Die Area for Current Drivers Applications
Authors: Gimenez Salvador P.
Published: May 2009

This paper proposes a new transistor layout, called here simply as Wave, that can be used for any technology, to improve the current driver and enhanced layout packing with respect to Multifinger and Waffle structures, regarding the same geometric factor. Discussions about this novel layout approach are performed regarding matching, avalanche and electro static discharge. To verify the benefits of the Wave structure, a comparison with a Multifinger and Waffle is carried out. Defining a figure-of-merit as integration factor [(W/L)/A], the Wave features a better efficiency than Multifinger and Waffle layouts, as 35.9 % and 28.1%, respectively. The Wave approach allows a saving of 26.1 % and 21.8% in the power SOI MOSFET size as compared to Multifinger and Waffle layouts.
Optimization of Blue/UV Sensors Using PIN Photodiodes in Thin-Film SOI Technology
Authors: Bulteel Olivier , Flandre Denis
Published: May 2009

The design and fabrication of high efficiency UV detectors for biomedical or environmental applications is very challenging. The goal of this work is to demonstrate the ability of SOI technology to implement such optical sensors. In this paper, we propose a structure of PIN photodiode implemented in a silicon thin film of a SOI wafer with an additional anti-reflection coating in silicon nitride. The simulation and the characterization of this device fit very well together. We also propose improved structures for this photodiode in SOI and in silicon-on-nothing technologies. For all the structures we study the appropriate thicknesses of the anti-reflection coating that could maximize the optical responsivities of the devices. Finally, we present two applications of our photodiodes proving their efficiency in biomedical field, such as DNA concentration measurement over a large range of characterization
Analytical Model for Conduction Band Nonparabolicity to Transport Analysis of Nano-Scale SOI MOSFET
Authors: Omura Yasuhisa
Published: May 2009

This paper reconsiders the mathematical formulation for the conventional nonparabolic band model, and discusses how the nonparabolicity of the conduction band impacts the effective masses of electrons that are confined within the barriers. To support this consideration, this paper proposes an analytical expression for the conduction-band effective mass of electrons including the term of band nonparabolicity.
Optimizing Spacer-to-Straggle Ratio in Underlap Double Gate MOSFETs for Low Voltage Analog and Digital Circuits
Authors: Kranti Abhinav , Rashmi R. , Armstrong G. Alastair
Published: May 2009

In this work, we report on the significance of non-overlap channel architecture in nanoscale double gate (DG) FETs to improve performance of low-voltage analog and digital circuits. It is shown that the low-voltage operation of a cascoded Operational Transconductance Amplifier (OTA) and 6-T SRAM cell can be considerably enhanced using underlap gate-source/drain design. The present work provides new opportunities for realizing future low-voltage analog and digital circuits with underlap DG FETs.
Harmonic Distortion Analysis of SOI Triple Gate FinFETs Applied to 2-MOS Balanced Structures
Authors: Doria Rodrigo T. , Martino Joao A. , Cerdeira Antonio , Pavanello Marcelo
Published: May 2009

This work presents an evaluation of the non-linearities exhibited in 2-MOS resistive structures composed by triple gate FinFETs with several fin widths down to 30 nm. The harmonic distortion has been analysed in terms of its third order component (HD3) as a function of the gate voltage, the input amplitude voltage and the fin width. The linearity has also been analysed with respect to the on-resistance, which constitutes a key parameter in such circuits. Along the harmonic distortion evaluation, the non-linearity causes are pointed out. At lower gate voltages, wider devices present smaller HD3 with respect to the narrower ones, while the contrary occurs at higher gate voltages.
Fabrication of Thick-film Silicon-on-Insulator by Separation by Implanted Oxygen Layer Transfer
Authors: Wei Xing , Wu Ai Min , Zhang Bo , Zhang Miao , Wang Xi , Lin Chenglu
Published: May 2009

In this paper, two approaches combined the Separation by IMplanted OXygen (SIMOX) layer transfer (SLT) process with Si epitaxy are proposed to fabricate thick-film Silicon-on-Insulator (SOI). Spectroscopic ellipsometry indicates thick-film SOI wafers with the top Si layers of 1430.86 {plus minus} 19.8 nm and 1476.44 {plus minus} 18.5 nm are achieved. Atomic-scale sharp interfaces between the top Si layer and buried oxide layers are observed by high-resolution transmission electron microscopy. Using atomic force microscopy, surface morphology of the SOI wafer is also investigated.
Pseudo-Mosfet Analysis of Proton Irradiated and Annealed SOI Wafer
Authors: Jung Sung-Hoon , Kim Jae-Min , Jung Lak-Myung , Lee Yong-Hyun , Cristoloveanu S. , Bae Young Ho
Published: May 2009

The total dose irradiation effect on the SOI wafer is analyzed at the material level by pseudo-MOSFET technique. The proton irradiation induces positively charged traps in the buried oxide (BOX) and amphoterically charged traps at the film-BOX interface. The amphoteric interface trap charges contribute to the shift in threshold and flatband voltages by accentuating or attenuating the effect of the positive fixed charge in the BOX. The inherent ambipolar pseudo-MOSFET characteristics reveal both NMOS and PMOS properties, making it possible to identify and separate the charges that contribute to the shift of the turn-on voltage. The negatively charged acceptor-like states are located in the upper part of bandgap whereas the positively charged donor-like states are situated in the lower part of bandgap. These interface trap states can be removed by low-temperature annealing, so that only the oxide trapped charges continue to govern the turn-on voltage shift.
Liquid/liquid Electrochemistry in Electroanalysis: Fundamentals Revisited
Authors: Vanysek Petr , Novák Vítězslav
Published: May 2009

The interface between two polarized liquids has applications in electroanalytical chemistry as a practical transducer arrangement. With same importance, such interface is studied with great interest by theoretical chemist and physicists to garner information about the fine structure of such interface. In our work we touch both of these aspects. In order to correlate the x-ray experimental work we determined Gibbs energies of transport for one supporting electrolyte and present a systematic method for determination of such parameters.
Modeling Non Equilibrium Potentiometry to Understand and Control Selectivity and Detection Limit
Authors: Lewenstam Andrzej , Sokalski Tomasz , Jasielec Jerzy , Kucza Witold , Filipek Robert , Wierzba Bartlomiej , Danielewski Marek
Published: May 2009

In most interpretations of ion-sensor response phase boundary potentials are used. They assume electroneutrality and equilibrium or steady-state, thus ignore electrochemical migration and time-dependent effects. It is in conflict with many experimental reports on ion-sensors, in which both kinetic (time-dependent) discrimination of ions to improve selectivity, and non-equilibrium transmembrane ion-transport for lowering detection limits, are deliberately used. The Nernst-Planck-Poisson (NPP) equations are used to model the non-equilibrium response. In the NPP model, electroneutrality and steady-state/equilibrium assumptions are abandoned and directly predicting the selectivity and the low detection limit variability over time, and the influence of other parameters, e.g. ion diffusibility, are possible. The NPP allows for solving the inverse problem i.e. to optimize sensor properties and measurement conditions via target functions and hierarchical modeling. The conditions under which experimentally measured selectivity coefficients are true (unbiased) and detection limits are optimized are demonstrated, and practical conclusions relevant to bioassays are derived.
The Use of Different Transduction Principles for Qualitative and Quantitative Chiral Gas Analysis
Authors: Hierlemann Andreas , Kurzawski Petra , Schurig Volker
Published: May 2009

Different chiral cyclodextrin derivatives, dissolved in a polysiloxane matrix, have been used as enantioselective sensitive coatings on a three-transducer microsystem including a calorimetric, a mass-sensitive and a capacitive chemical sensor. Upon exposure to chiral analytes, such as methyl lactate and methyl-2-chloropropionate, all three transducers showed a distinct chiral discrimination of these analytes. It was shown that the absorption and desorption kinetics of the two enantiomers of, e.g., methyl-2-chloropropionate are sufficiently different to produce sensor signal features that enable an accurate determination of the enantiomeric purity and of the enantiomeric composition of the chiral analyte or mixture under investigation.
Generating and Using Data of Higher Dimension for Gas-Phase Chemical Sensing
Authors: Raman Baranidharan , Hertz Joshua , Benkstein Kurt , Meier Douglas , Mungle Casey , Semancik Steve
Published: May 2009

Methods to acquire and analyze rich data streams from sensors are helpful, if not required, to track chemical components within complex gas-phase environments. We describe a MEMS-based microsensor technology that populates multi-element arrays with multiple sensing materials and also cycles the temperatures of the elements as a function of time. Various processing methods have been applied to the resulting databases in order to recognize and classify target analytes in dynamic background conditions.
The Metal Organic Films for Tailorable Chemical Sensing on Microcantilevers
Authors: Houk Ronald J. , Lee Jin-Hwan , Allendorf Mark , Hesketh Peter
Published: May 2009

A new generation of versatile microcantilever sensors with tailorable nanoporous metal-organic frameworks (MOFs) has been successfully demonstrated. Two metal-organic frameworks (MOFs), HKUST-1 and MOF-508 were characterized to demonstrate new stress-induced sensing mechanism. The microcantilever sensors were fabricated on silicon-on-insulator (SOI) wafers with 1 µm thickness of the final beam. The results exhibited extraordinary sensitivity, and a selective reversible response for chemical detection (1). Metal-organic frameworks (MOFs) are attracting attention as the ideal material for sensing applications because of their nanoporosity, ultrahigh surface area, and the fact that they can be tailored for adsorption of specific analytes (1). In this work, HKUST-1 was prepared and characterized to demonstrate that different MOFs can detect multiple analytes with microcantilever array (2). The elastic properties of MOFs were measured by nano-indentation test (MTS Nano-Indentor XP) and Raman microscope (Renishaw) was used to characterize coated MOFs-thin films on gold compared with MOFs powders.
Electrochemically Prepared Beta Microirradiators
Authors: Steeb Jennifer , Josowicz Mira , Janata Jiri
Published: May 2009

Here we report the fabrication of two types microirradiators, consisting of recessed disk and protruding wire with low beta-energy radionuclide Ni-63 electrodeposited onto 25 μm diameter Pt wire. Ni-63 is confined to a small surface area of the microelectrode; hence, this tool provides a means of delivery of localized, large dose density of beta radiation to the object, but a minimal dose exposure to the user. The activity levels of Ni-63 emitted from the recessed disk and protruding wire are of 0.25 and 1 Bq, respectively. The corresponding beta particles flux levels emitted from the recessed disk and protruding wire are of 51 and 11 kBq/cm2, respectively. These values, measured experimentally using liquid scintillation counting, fit very well the expected values of activity for each microirradiator, calculated considering the self-absorption effect, typical for low energy beta particles. In order to determine the optimal configuration the dose rates for varying distances from the object were calculated.
Millisecond Annealing Junctions for Near-Scaling-Limit Bulk CMOS Using Raised Source/Drain Extensions
Authors: Hane Masami
Published: May 2009

This paper reviews an effective way to pursue further scaling of planar-bulk CMOSFETs featuring "effectively" shallow junctions in selective epitaxial growth of the raised source/drain extension(RSDext) regions processed with high-temperature millisecond annealing (MSA).
Boron Diffusion Behavior During the Formation of Shallow p+/n Junction Using the Combination of Ge Pre-amorphization Implantation, Pre-Annealing RTA and Post-Annealing Non-Melt Excimer Laser(NLA) Processes
Authors: Binti Aid Siti Rahmah , Matsumoto Satoru , Suzuki Toshiharu , Fuse Gensyu , Nakazawa Toshihiro
Published: May 2009

In this paper, we studied the behavior of boron diffusion during the formation of shallow p+/n junction. The combination of Ge-PAI with low-energy boron implantation, pre-annealing RTA and post annealing NLA processes lead to the ultra-fast-diffusion of boron which increase the junction depth of the annealed samples.
Ultra-Shallow Junction Formation by Plasma doping and Excimer Laser Annealing
Authors: Jung Lak-Myung , Do Seung-Woo , Kim Jae-Min , Kong Seong Ho , Nam Ki-Hong , Lee Yong-Hyun
Published: May 2009

Plasma doping (PLAD) process using PH3 plasma is presented to fabricate n+/p ultra shallow junction at room temperature. Directly after the PLAD, a pre-annealing has been conducted for 5 min at 500 {degree sign}C in thermal furnace. ArF excimer laser annealing (ELA) process was then followed with an increment of 20 mJ/cm2 in the laser energy ranging from 400 to 500 mJ/cm2. When the laser energy density was larger than 460 mJ/cm2, a reduced sheet resistance was observed. In order to examine the crystalline defects generated during PLAD, the transmission electron microscopy (TEM) and double crystal X-ray diffraction (DXRD) measurements have been made. With optimized PLAD and ELA conditions, junction depth of 30 nm and sheet resistance of 151.6 Ω/□ could be obtained.
The Evaluation of State-of-the-Art Front-End Structures by the Differential Hall Effect Continuous Anodic Oxidation Technique
Authors: Prussin Simon A. , Reyes Jason
Published: May 2009

The differential Hall effect CAOT permits rapid, accurate measurements of mobility, resistivity, and carrier concentration. This permits us to extract defect scattering contributions to the mobility for comparison of doping and annealing techniques. The co-implantation of C with P was evaluated and showed that besides restricting the diffusion of P, the carrier concentration was significantly reduced. The application of DHE CAOT to the evaluation of doped polysilicon films permitted the evaluation of carrier concentration and mobility profiles. The latter has been correlated to grain size.
Opportunities and Challenges for Germanium and Silicon-Germanium Channel p-FETs
Authors: Bedell Stephen W. , Daval Nicolas , Fogel Keith , Shimizu Ken , Ott John , Newbury Joseph , Sadana Devendra
Published: May 2009

The electrical behavior of SiGe and pure Ge channel p-FET devices will be presented and discussed in this paper. By fabricating short channel SiGe, relaxed Ge and strained Ge channel devices with scaled high-κ/metal gate stacks, we demonstrate three main advantages of using these types of devices: i) more aggressive TINV scaling of the gate dielectric due to lower temperature processing, ii) band gap engineering to allow better control of threshold voltage and possibly iii) lower external resistance due to the higher B activation in these materials. The main drawback inherent to relaxed Ge and biaxially strained Ge and SiGe channels is that the ability to have improved transport properties without the need for external stressors always seems to come with a large penalty in off state leakage. The ION and IOFF in these devices are compared to recent work by others and a general trend is observed.
Influence of Interfacial Oxygen and Carbon on Misfit Dislocation Generation in SiGe Epitaxial Layers
Authors: Fukuda Masahiro , Shimamune Yosuke , Tanahashi Katsuto , Ikeda Keiji , Nishikawa Masatoshi , Maekawa Hirotaka , Tamura Naoyoshi , Mori Toshifumi , Shimizu Atsuo , Kase Masataka
Published: May 2009

The influence of interfacial oxygen (O) and carbon (C) at the SiGe epi/Si interface on misfit dislocation generation and their impact on embedded SiGe device performance were studied. It is found that the interfacial O and C increased the dislocation nuclei, and degraded the channel hole mobility, resulting in the degradation of its device performance. We concluded that it is indispensable to realize not only the low temperature SiGe growth but also the low temperature in-situ precleaning to improve device performance. By using the low temperature SiGe process at 550{degree sign} C including in-situ precleaning and SiGe growth, high device performance such as saturation drain current (Ion) of 765 μA/μm were achieved at off current (Ioff) of 100 nA/μm at drain bias (VDD) = 1.0 V by suppressing of dislocation generation.
On the Origin of Anomalous VTH Shift in high-k MOSFETs
Authors: Toriumi Akira , Kita Koji
Published: May 2009

Metal/high-k gate stack technology is now about to enter production. However, there are so many issues that have not been understood yet. VTH control is the most serious concern for high performance and low power CMOS applications. In this paper, our understanding of anomalous VTH shift observed in high-k gate stacks is presented from the viewpoint of dipole formation at high-k/SiO2 interface.
Engineering Band-Edge High-κ/Metal Gate n-MOSFETs with Cap Layers Containing Group IIA and IIIB Elements by Atomic Layer Deposition
Authors: Jagannathan Hemanth , Edge Lisa F. , Jamison Paul , Iijima Ryosuke , Narayanan Vijay , Paruchuri Vamsi K. , Clark Robert , Consiglio Steven , Wajda Cory , Leusink Gert
Published: May 2009

This paper presents studies performed in engineering high-k metal gate stacks by using capping layers containing Group IIA and IIIB elements. Both high-k gate dielectric (HfO2) and capping materials, namely, the oxides of barium, lanthanum and yttrium are deposited by atomic layer deposition (ALD) to offer superior process control and flexibility. Position specific insertion of cap layers into the gate stack is studied and the device tradeoffs are highlighted. The magnitude of Vt shift is correlated to the electronegativity of the cap layer species and its relative position in the gate stack. For a given cap position, BaO provides the maximum Vt shift, followed by La2O3 and Y2O3 caps. Ozone based ALD processes are shown to adversely impact Tinv scaling due to the re-growth of the interface layer between the high-k and the silicon substrate. Significant improvements in Tinv scaling are obtained by migrating to a water based ALD process.
Three-Dimensional Atom-Probe Tomographic Studies of Nickel Monosilicide/Silicon Interfaces on a Subnanometer Scale
Authors: Adusumilli Praneet , Murray Conal E. , Lauhon Lincoln J. , Avayu Ori , Rosenwaks Yossi , Seidman David N.
Published: May 2009

Three-dimensional atom-probe tomography was utilized to study the distribution of M (M = Pt or Pd) after silicidation of a solid-solution Ni0.95M0.05 thin-film on Si(100). Both Pt and Pd segregate at the (Ni1-xMx)Si/Si(100) heterophase interface and may be responsible for the increased resistance of (Ni1-xMx)Si to agglomeration at elevated temperatures. Direct evidence of Pt short-circuit diffusion via grain boundaries, Harrison regime-B, is found after silicidation to form (Ni0.99Pt0.01)Si. This underscores the importance of interfacial phenomena in stabilizing this low-resistivity phase, providing insights into the modification of NiSi texture, grain size, and morphology caused by Pt. The relative shift in work function between as-deposited and annealed states is greater for Ni(Pt)Si than for NiSi as determined by Kelvin probe force-microscopy. The nickel monosilicide/Si heterophase interface is reconstructed in three-dimensions and its chemical roughness is evaluated.
Properties of ErSi(2−x) Contacts Formed on Si(1−x)C(x) Epitaxial Layers
Authors: Alptekin Emre , Ozturk Mehmet , Misra Veena , Cho Yonah , Kim Yihwan , Chopra Saurabh
Published: May 2009

Erbium silicide (ErSi2−y) formation was investigated on Si1−xCx epitaxial layers grown on Si substrates. The silicide ﬁlms were formed by rapid thermal annealing of sputter deposited erbium layers. The sheet resistance of the silicide ﬁlms formed on Si1−xCx epitaxial layers was found to be equal to or less than the sheet resistance of the ﬁlms formed on Si epitaxial layers. At 600{degree sign}C, an average resistivity of 114 was obtained. The silicide grains were found to be epitaxially aligned to the substrate along the (100) orientation regardless of the carbon concentration. Compositional analysis of the ﬁlms indicated carbon accumulation at the ErSi2−y/Si1−xCx interface with no carbon incorporation in the silicide. The ﬁlms formed on Si1−xCx epitaxial layers exhibited smooth surface morphology free of pinholes contrary to the silicides formed on Si. The electron Schottky barrier height of ErSi2−y/Si1−xCx diodes was found to reduce by 80meV with 1.2%C.
Development toward Wafer-Scale Graphene RF Electronics
Authors: Moon Jeong , Curtis D , Hu M , Wong D , Campbell Paul , Jernigan Glenn , Tedesco Joseph L. , VanMil Brenda , Myers-Ward R. L. , Eddy Charles , Gaskill D. K. , Robinson Joshua , Fanton Mark , Asbeck P
Published: May 2009

We will present recent development of graphene FET technology on a wafer scale, including epitaxial graphene growth, device fabrication and characterization. The epitaxial growth of graphene on 2-inch wafers were fabricated via graphitization of Siface SiC(0001) substrates. The sheet electron carrier density of these layers were typically 10-13 cm2 at room temperature and had mobility of ~ 1500 cm2 V-1 s-1 or higher. Graphene FETs were fabricated with source and drain non-alloyed ohmic metal schemes. Metal gates were used on top of atomic-layer-deposited high-k (Al2O3) gate dielectric layer. DC and RF performance of the world's first epitaxial graphene RF FETs is presented.
Surface Microscopy Characterizations of Large Size Graphene Films Grown by Surface Segregation on Ni and Transferred to Si/SiO2 Substrate
Authors: Pandey Deepak , Prakash Gyan , Yu Qingkai , Cao Helin , Jauregui Luis , Pei Steven , Chen Yong P.
Published: May 2009

We report surface microscopy characterizations of large size graphene films (up to mm) grown on polycrystalline Ni foils and transferred to Si/SiO2. Wrinkles in such films are studied by both atomic force microscopy (AFM) and scanning tunneling microscopy (STM). Local graphitic lattice structures of the films are imaged with atomic-resolution STM and compared with those of the highly ordered pyrolytic graphite (HOPG).
Epitaxial Graphene: Designing a New Electronics Material
Authors: De Heer Walter A. , Berger C. , Wu X. S. , Sprinkle M. , Hu Y. , Ruan M. , Conrad E. , Orlita M. , Potemski M.
Published: May 2009

Epitaxial graphene (EG) is a new material that consists of one or more graphene layers that are grown on single crystal silicon carbide. EG research has for the past 6 years focused on material production and processing. High quality material can now be produced and processing methods are promising. Progress is reviewed here with an emphasis on the recently discovered multilayered epitaxial graphene (MEG) which is multilayered yet exhibits the properties of a single layer. The status of this rapidly developing field is briefly reviewed with an emphasis on properties and effects that are relevant for electronics applications.
Large-grained and Highly-ordered Graphene Synthesized by Radio Frequency Plasma-enhanced Chemical Vapor Deposition
Authors: Woo Yunsung , Kim Dong-Chu , Jeon Dae-Young , Chung Hyun-Jong , Shin Sung-Mo , Li Xiang-Shu , Kwon Young-Nam , Seo David H , Shin Jaikwang , Chung U-In , Seo Sunae
Published: May 2009

We have synthesized a very thin graphite film on polycrystalline Ni foil using radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) at relatively low temperature. Structural analysis through electron diffraction and Raman spectroscopy demonstrated that the PECVD grown graphite film consists of large grains sized over tens of microns and is highly ordered structure exhibiting Bernal stacking despite of low synthetic temperature of 850oC. Accordingly, the high carrier mobility of 4,500 cm2/Vsec was obtained at room temperature from a monolayer of PECVD grown graphene, which is higher than any reported value of CVD-grown graphene.
Epitaxial Graphene Growth on SiC Wafers
Authors: Gaskill D. K. , Jernigan Glenn , Campbell Paul , Tedesco Joseph L. , Culbertson James , VanMil Brenda , Myers-Ward R. L. , Eddy Charles , Moon Jeong , Curtis D , Hu M , Wong D , McGuire C , Robinson Joshua , Fanton Mark , Stitt T. , Stitt T. , Snyder David , Wang X. , Frantz Eric
Published: May 2009

An in vacuo thermal desorption process has been accomplished to form epitaxial graphene (EG) on 4H- and 6H-SiC substrates using a commercial chemical vapor deposition reactor. Correlation of growth conditions and the morphology and electrical properties of EG are described. Raman spectra of EG on Si-face samples were dominated by monolayer thickness. This approach was used to grow EG on 50 mm SiC wafers that were subsequently fabricated into field effect transistors with fmax of 14 GHz.
Low Temperature Graphene Growth
Authors: Kumar Shishir , McEvoy Niall , Lutz Tarek , Keeley Gareth , Whiteside Nicholas , Blau W. , Duesberg Georg S.
Published: May 2009

We demonstrate the growth of graphene films on nickel substrates by chemical vapour deposition using acetylene at temperatures as low as 750 {degree sign}C, opening a viable route for its scalable production. Raman spectroscopy was used to confirm defect-free mono and multilayer graphene at and above this temperature, and of defective graphene at lower temperatures. Atomic force microscopy and scanning electron microscopy performed directly on the films give an indication of graphene flake size, morphology and also the topography on substrate. An unexpected dependence of graphene thickness on precursor dwell time is reported. This together with low temperature growth suggests deficiencies in existing growth models and hints at a more complicated growth mechanism.