bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retarding Field Analyzer for Ion Energy Distribution Measurement Through a Radio‐Frequency or Pulsed Biased Sheath
Authors: Gahan David , Dolinaj Borislav , Hayden Chanel , Hopkins Michael B. 
Published: June 2009

AbstractA compact, floating retarding field energy analyzer for measurement of ion energy distributions impacting an electrode through a radio‐frequency or pulsed bias sheath in a plasma discharge is presented. The analyzer is designed to sit on the electrode surface, in place of the substrate, and wide‐band low pass filters allow it to float at the electrode potential. This avoids the need for modification of the electrode. The capabilities of the analyzer are demonstrated through ion energy distribution and electron energy distribution measurements at the electrode surface in an inductively coupled plasma reactor. For a sinusoidal radio‐frequency driving signal applied to the electrode the analyzer is shown to resolve ions with different mass. When the radio‐frequency power to the plasma pulsed the analyzer is used to resolve the ion energy distributions at different times in the pulse. The high energy tail of the electron energy distribution reaching the electrode surface is also measured. A comparison with a Langmuir probe shows exceptional agreement in the energy region where both devices overlap.
Multiphysics Coupling Simulation of Silicon Nitride CVD Using an RLSA Source
Authors: Brcka Jozef , Kang Song‐Yun 
Published: June 2009

AbstractThe plasma produced by a radial line slot antenna (RLSA) source is discussed based on a simulation using a multiphysics coupled 2D fluid model. The technological aspects in a silicon nitride chemical vapor deposition (CVD) process using a disilane and ammonia mixture are addressed. The model includes the incompressible Navier–Stokes module (INSM), the multiple convection and diffusion transport modules (CDTM), the convection and conduction heat transport (CCHT) for gas and electron temperature, and the transverse electromagnetic (TEM) wave propagation for a planar microwave source structure coupled to the plasma. The dominant precursors, deposition rate and mechanisms, and performance of the CVD process in terms of the film properties are investigated. The ionic and radical component 2D distributions are calculated and the simulation results are correlated with experimental data. The significant impact of the surface reactions with the involvement of H, NH, and NxHy radicals and ions is established.
Monte Carlo Simulation of Electrons' and Ions' Trajectories in Magnetron Sputtering Systems
Authors: Holik Miroslav , Bradley James , Bellido‐Gonzalez Victor , Monaghan Dermot 
Published: June 2009

AbstractA 3D simulation system has been developed to study electron and ion densities and other plasma parameters in circular and rectangular magnetron sputtering systems. Typically, 105 particles of each species are tracked simultaneously for a time period when the plasma parameters' distributions get stabilised. During this period, the particles undergo Lorentz force and different kinds of collisions. The collisions are generated by Monte Carlo method using null‐collision technique.
Repair and online mechanical integrity monitoring
Authors: Ternowchek Sam , Deonarine Sheldon 
Published: June 2009

AbstractDescribed in this article are a series of cracks found in a vessel during a routine inspection. The welding methods and procedures used to address unique problems associated with the repair of these cracks are described. After the repairs were completed and inspected, an online Acoustic Emission (AE) system was installed to monitor the mechanical integrity of the vessel while in operation. The system presents data locally for use by operations personnel as well as remotely, via the internet, for detailed analysis by engineers.A major benefit of online monitoring is that it can show an association between defect growth and operating conditions should process information be recorded by the system. AE data, therefore, can help optimize the operating conditions to minimize or eliminate defect growth and equipment damage.Until recently, online AE monitoring was confined to a few, specialized applications such as high energy piping in refineries and power plants. The advent of better computers and software, high speed internet connections, and more reliable instrumentation has made remote monitoring a reality. The AE specialist can now operate the AE system and evaluate online data remotely and report results by web site or e‐mail.The AE system has also been of use as a process monitor in addition to the vessel integrity monitor. It provides an ongoing condition assessment of the vessel. Gasket leaks on start up and valve leakage are some of the problems that have been identified with the online AE system. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2010
Suppressed surface‐recombination structure and surface passivation for improving current gain of 4H‐SiC BJTs
Authors: Nonaka Kenichi , Horiuchi Akihiko , Negoro Yuki , Iwanaga Kensuke , Yokoyama Seiichi , Hashimoto Hideki , Sato Masashi , Maeyama Yusuke , Shimizu Masaaki , Iwakuro Hiroaki 
Published: June 2009

Abstract4H‐SiC bipolar junction transistors (BJTs) are one of the promising candidates for next‐generation power devices. 4H‐SiC BJTs have the advantages of low on‐resistance and high temperature capability. On the other hand, high common emitter current gain is required from a practical use point of view because BJTs are current‐controlled devices. In order to improve the current gain of 4H‐SiC BJTs, we have concentrated on suppressing surface recombination on the SiC surface, which is a critical limiting factor of the current gain and can be suppressed by reducing carrier density and/or trap density. We have proposed novel 4H‐SiC bipolar junction transistors with suppressed surface‐recombination structure: SSR‐BJTs that have the SiC surface with low carrier density, characterized by a lightly doped n‐type layer (LDN layer) and a highly resistive p‐type region (HRP region). In addition, surface passivation suitable for reducing surface traps has been investigated by applying a new characterization method of surface‐recombination current in which the sp · Ls value, a product of a surface‐recombination velocity (sp) and a surface‐diffusion length (Ls), is derived from an analysis of forward I–V characteristics of SiC pn diodes. We have experimentally demonstrated that the sp · Ls value is a practical indicator to evaluate surface passivation. By using the characterization, an effective passivation method with the combination of a pyrogenic oxidation, a post‐oxidation anneal in H2 ambient, and an anneal in NH3 ambient has been developed. SSR‐BJTs with a variety of device structures and process conditions have been fabricated to investigate their characteristics. A fabricated SSR‐BJT showed a recorded maximum current gain of 134 at room temperature with a specific on‐resistance of 3.2 mΩ cm2 and a blocking voltage VCEO of 950 V. The SSR‐BJT kept a current gain of 60 °C at 250 °C with a specific on‐resistance of 8 mΩ cm2. These results have demonstrated the outstanding current‐gain capability of the SSR‐BJTs compared to conventional BJTs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Amorphisation and sub‐100‐nm exfoliation of hydrogen‐ion‐implanted silicon
Authors: Moutanabbir O. , Terreault B. , Giguère A. 
Published: June 2009

AbstractThe basic physics and the chemical role of H in amorphisation and exfoliation of H‐ion‐implanted silicon were investigated by Raman scattering and transmission electron microscopy. We found that a continuous, thermally stable, 50‐nm‐thick amorphous layer formed upon implantation of 5‐keV H ions at 150 K. Such amorphisation is contrary to earlier theoretical predictions but gives support to recent molecular dynamics calculations. After high temperature annealing, H‐saturated mono‐ and di‐vacancies became dominant in the Si‐H Raman spectrum. (001) platelets and microcracks apppeared in the c‐Si beyond the a‐Si layer, leading to the exfoliation of a 90‐nm thick layer. Deuterium implantation leads to the formation of a thicker (∼100 nm) amorphous layer but inhibits exfoliation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micropipes in silicon carbide crystals
Authors: Gutkin Mikhail Yu. , Sheinerman Alexander G. , Argunova Tatiana S. 
Published: June 2009

AbstractWe provide a brief review of our recent experimental observations, theoretical and computer models aimed at describing the interaction and transformations of micropipes – dislocated cylindrical pores – in growing bulk crystals of silicon carbide. We describe theoretically the interactions of micropipes with each other as well as with the free surface of the growing crystal. As a result, we explain the experimental observations of ramifying micropipes and calculate the conditions for micropipe split and possible further overgrowth. We also provide the results of our computer simulation of the evolution of a random ensemble of micropipes in the course of the growth of bulk SiC crystals. The simulation has confirmed the presence of both planar and twisted configuration of micropipes observed by means of synchrotron radiation X‐ray phase sensitive radiography. Finally, we consider the elastic interaction of micropipes with inclusions of minority polytypes in SiC bulk crystals. We demonstrate that micropipes are attracted to the minority polytype boundaries and can form pores that grow along these boundaries. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of the strain‐relaxation induced defect creation on the leakage current of embedded Si1–xGex source/drain junctions
Authors: Gonzalez Mireia Bargallo , Simoen Eddy , Vissouvanadin Bertrand , Eneman Geert , Verheyen Peter , Loo Roger , Claeys Cor , Machkaoutsan Vladimir , Tomasini Pierre , Thomas Shawn 
Published: June 2009

AbstractThe purpose of this paper is to evaluate the role of the strain‐relaxation processes on the leakage current of embedded SiGe S/D junctions. Current‐voltage (I‐V) and capacitance‐voltage (C‐V) characteristics were measured to further investigate the relaxation degree of embedded SiGe S/D junctions in the regime where partial relaxation by misfits dislocations is assumed, yielding a reduction of the leakage current density. Further, the impact of the ion implantation‐related defects on the electrical performance is discussed. The analysis is complemented with structural characterization based on High Resolution Transmission Electron Microscopy (HRTEM) and Nomarski microscopy. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anisotropy of crack and dislocation formation in GaAs
Authors: Ratschinski Ingmar , Heyroth Frank , Fränzel Wolfgang , Leipner Hartmut S. 
Published: June 2009

AbstractThe dependence of cracking at Vickers indentations in (100) GaAs was investigated for different dopings by electron microscopy. Depending on the load, the formation of cracks was studied. In semiinsulating carbon‐doped GaAs, a clear anisotropy in the cracking pattern exists with cracks running preferentially along the ± [011] directions. In contrast, in n‐type as well as in p‐type GaAs little or no anisotropic crack pattern can be recognized. The formation and propagation of cracks does not correlate with the formation of the dislocation rosette. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time‐resolved measurements of dislocation‐related photoluminescence bands in silicon
Authors: Steinman E. A. , Kenyon A. J. , Tereshchenko A. N. 
Published: June 2009

AbstractDislocation related luminescence (DRL) in Si was analyzed using time‐resolved techniques. A set of samples exhibiting different spectral features in the range of the D1 band was prepared by plastic deformation and subsequent thermal treatment. For all samples the sequence of time constants texc < tD4 < tD1 < tD2 has been observed where texc, tD4, tD1, and tD2 denote the time decay constants for the TO phonon replica of the Si bound exciton (TO BE) and D4, D1, and D2 DRL bands, respectively. It should be noted that the relation between decay times of the D1 and D2 bands remained same for all sub‐bands in the D1 family. Our results imply that transitions of similar nature are responsible for the bands. On the other hand, the lack of correlation between D1/D2 decay times and contamination levels suggests that intrinsic properties of dislocations are responsible for the corresponding transitions. We analyzed this observation in comparison with previous results and propose a model of recombination between two shallow and one deep level for D1/D2 bands. Differences in decay times are attributed to different spatial separation of shallow traps from a common deep trap. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Correlation of electrical and luminescence properties of a dislocation network with its microscopic structure
Authors: Mchedlidze Teimuraz , Wilhelm Thomas , Arguirov Tzanimir , Trushin Maxim , Reiche Manfred , Kittler Martin 
Published: June 2009

AbstractThe direct bonding of Si wafers reproducibly forms dislocation networks (DN) with a microscopic structure defined by the mutual crystallographic orientation between the pair of wafers used for the bonding procedure. This allows studying the electrical and optical properties of specific dislocations. In the present work three different DN structures were investigated using transmission electron microscopy (TEM), photoluminescence (PL) and deep level transient spectroscopy (DLTS). The results show close correlation between the structural, electrical and optical properties of dislocations and opens a possibility to identify structural peculiarities of the dislocations responsible for the high intensity of photoluminescence. Namely, the obtained results suggest that PL at ∼0.8 eV is related to screw dislocations in DN. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Proton backscattering by point and extended defects in ion‐implanted Si
Authors: Sobolev Nikolay , Sakharov Vladimir , Serenkov Igor , Kalyadin Anton , Vdovin Vladimir 
Published: June 2009

AbstractThe backscattering of 230‐keV protons, the depth dependences of the full width at the half minimum (FWHM) of proton angular scans and TEM were used to study the structural perfection of Si single crystals implanted with Er and Si ions at doses lower and higher than the respective amorphization thresholds. Implantation of 2‐MeV Er ions at a dose of 5x1013 cm–2 was found to produce high concentrations of point defects without amorphization of the Si layer. After the implantation of 100‐keV Si ions at a dose of 1x1017 cm–2 exceeding the amorphization threshold by two orders of magnitude, we observed a high density of extended defects but no amorphization. The dechanneling by point and extended defects was found to have different dependences (decreasing and increasing, respectively) of the scan FWHM on the scan depth. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of steps on dislocations in CVD diamond grown on {001} substrates
Authors: Martineau Philip , Gaukroger Mike , Khan Riz , Evans Dave 
Published: June 2009

AbstractSingle crystal CVD synthetic diamond samples grown on (001) substrates have been studied using X‐ray topography, photoluminescence imaging, cathodoluminescence imaging and transmission electron microscopy. X‐ray section topographs sampling a plane very close to the surface of a (010) cross‐sectional slice show contrast that is closely correlated with photoluminescence image contrast relating to differences in incorporation of point defects on step risers and terraces during growth. The point defect content is too low to influence X‐ray topography contrast and therefore the correlation suggests a difference between the dislocation content for terrace and riser growth. Dislocations imaged in cathodoluminescence have been observed to follow paths that are strongly influenced by step flow during growth. Transmission electron micrographs show [001] dislocations with sections of <110> 60° or edge dislocations in configurations consistent with formation as a result of step flow growth. It is proposed that a passing riser can cause dislocations to switch from [001] to [101] line direction when this minimises the increase in the energy associated with the dislocation as riser growth proceeds. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antidiarrhoeal and spasmolytic activities of the methanolic crude extract ofAlstonia scholarisL. are mediated through calcium channel blockade
Authors: Shah Abdul Jabbar , Gowani Saqib Ali , Zuberi Akber Jalil , Ghayur Muhammad Nabeel , Gilani Anwarul Hassan 
Published: June 2009

AbstractThis study was aimed to provide a pharmacological basis to the medicinal use ofAlstonia scholarisas an antidiarrhoeal and antispasmodic by usingin vivoandin vitrotechniques. In thein vivostudy the crude extract ofAlstonia scholaris(As.Cr), which tested positive for the presence of alkaloids, provided 31–84% protection against castor oil‐induced diarrhoea in mice at 100–1000 mg/kg doses, similar to loperamide. In isolated rabbit jejunum preparation, the As.Cr caused inhibition of spontaneous and high K+(80 mm)‐induced contractions, with respective EC50values of 1.04 (0.73–1.48) and 1.02 mg/mL (0.56–1.84; 95% CI), thus showing spasmolytic activity mediated possibly through calcium channel blockade (CCB). The CCB activity was further confirmed when pretreatment of the tissue with the As.Cr (0.3–1 mg/mL) caused a rightward shift in the Ca++concentration‐response curves similar to verapamil, a standard calcium channel blocker. Loperamide also inhibited spontaneous and high K+precontractions as well as shifted the Ca++CRCs to the right. These results indicate that the crude extract ofAlstonia scholarispossesses antidiarrhoeal and spasmolytic effects, mediated possibly through the presence of CCB‐like constituent(s) and this study provides a mechanistic base for its medicinal use in diarrhoea and colic. Copyright © 2009 John Wiley & Sons, Ltd.
A DFT study on the hydrolysis mechanism of NH‐tautomeric antitumors of [HL][trans‐RuCl4L(dmso‐S)]
Authors: Chen Jin Can , Chen Lan Mei , Liao Si Yan , Zheng Kang Cheng , Ji Liang Nian 
Published: June 2009

AbstractThe hydrolysis process of Ru (III) complex [Htrz][trans‐RuCl4(1‐H‐1,2,4‐triazole)(dmso‐S)] 1, a potential antitumor complex similar to the well‐known anticancer agent [ImH][trans‐RuCl4(Im)(dmso‐S)] (NAMI‐A), has been investigated by using density functional theory (DFT) method, and the solvent effect was also considered and calculated by conductor‐like polarizable calculation model (CPCM). Meanwhile, the hydrolysis process of the NH‐tautomeric isomer, [Htrz][trans‐RuCl4(4‐H‐1,2,4‐triazole)(dmso‐S)] 2, was also modeled and predicted by the same methods. The structural characteristics and the detailed energy profiles for the hydrolysis processes of two isomers have been obtained. The analysis of thermodynamic and kinetic characteristics of hydrolysis reaction suggests the following: for the first hydrolysis step, the Complex 1 has lower hydrolysis rate than the reported anticancer drug NAMI‐A, and the result is in accordance with experimental one. However, Complex 1 has obviously higher hydrolysis rate than its isomer Complex 2, and the result was reasonably explained in theory. For the second hydrolysis step, the formation of cis‐diaqua species is thermodynamic preferred to that of trans isomers. In addition, the trend in nucleophilic attack abilities (A) of hydrolysis products by pertinent biomolecules was revealed and predicted. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Membrane permeation continuous‐flow isotope ratio mass spectrometry for on‐line carbon isotope ratio determination
Authors: Tremblay Patrice , Savard Martine M , Smirnoff Anna , Paquin Real 
Published: June 2009

AbstractGaseous membrane permeation (MP) technologies have been combined with continuous‐flow isotope ratio mass spectrometry for on‐line δ13C measurements. The experimental setup of membrane permeation‐gas chromatography/combustion/isotope ratio mass spectrometry (MP‐GC/C/IRMS) quantitatively traps gas streams in membrane permeation experiments under steady‐state conditions and performs on‐line gas transfer into a GC/C/IRMS system. A commercial polydimethylsiloxane (PDMS) membrane sheet was used for the experiments. Laboratory tests using CO2 demonstrate that the whole process does not fractionate the C isotopes of CO2. Moreover, the δ13C values of CO2 permeated on‐line give the same isotopic results as off‐line static dual‐inlet IRMS δ13C measurements. Formaldehyde generated from aqueous formaldehyde solutions has also been used as the feed gas for permeation experiments and on‐line δ13C determination. The feed‐formaldehyde δ13C value was pre‐determined by sampling the headspace of the thermostated aqueous formaldehyde solution. Comparison of the results obtained by headspace with those from direct aqueous formaldehyde injection confirms that the headspace sampling does not generate isotopic fractionation, but the permeated formaldehyde analyzed on‐line yields a 13C enrichment relative to the feed δ13C value, the isotopic fractionation being 1.0026 ± 0.0003. The δ13C values have been normalized using an adapted two‐point isotopic calibration for δ13C values ranging from −42 to −10‰. The MP‐GC/C/IRMS system allows the δ13C determination of formaldehyde without chemical derivatization or additional analytical imprecision. Copyright © 2009 John Wiley & Sons, Ltd.
Biodiversity‐ecosystem function research: Insights gained from streams
Authors: Lecerf A. , Richardson J. S. 
Published: June 2009

AbstractIn this review, we address the extent to which stream ecology has contributed to biodiversity‐ecosystem function (BEF) theory and empirical testing. BEF research first targeted the implications of the ongoing loss of biodiversity for ecosystems and humans. Terrestrial ecology has played a leading role in this field, whereas the contribution of riverine science to the debate has been more limited. Nevertheless, a considerable merit of stream ecology has been to consider a wide range of ecological groups (riparian litter producers, aquatic micro‐fungi, macroinvertebrates, and fishes). Through a meta‐analysis of these unique data, we show that the relative importance of species numberversusassemblage composition increases as we go towards higher trophic levels. Whether this pattern is general or specific to stream ecosystems needs to be evaluated through cross‐ecosystem comparisons looking more closely at mechanistic processes. It is evident from stream studies that trophic and non‐trophic (e.g. facilitation) interactions govern the functional consequences of biodiversity. These studies also indicate that richness‐function relationships are altered by a multitude of factors, such as evenness, non‐taxonomic diversity (genetic/phenotypic diversity), species extinction order, the environmental context, as well as experimental setups. This review highlights the relevance of stream ecology to BEF research. Copyright © 2009 John Wiley & Sons, Ltd.