bluuebunny/crossref_metadata_2025_split huggingface dataset:
Beryllium Oxide Dielectric Heat Sinks for Electronic Devices
Authors: Hessinger P. , Strott A. , Haura B. 
Published: September 2009

Beryllium oxide is unique among precision ceramic products in that it has a high electrical resistivity and low dielectric loss combined with a thermal conductivity equal to that of aluminum. Because of this advantageous combination of properties, it has found increased use as a dielectric heat sink which can insulate electronic devices electrically, and at the same time remove substantial quantities of heat from them to a chassis heat sink.
High-purity beryllia insulators are produced by ceramic fabrication techniques such as cold-pressing, slip-casting, and extrusion, followed by sintering at temperatures above 1500 C. By the application of precision fabricating techniques, close dimensional tolerances and high surface smoothness can be obtained for maximum compatibility with metal components.
The application of a 0.030 in. beryllia dielectric heat sink beneath a power transistor has, for example, reduced the thermal resistance by a factor of 10 from that obtained when using a thin mica or anodized aluminum insulator. Tests conducted to date have indicated a potential increase of device power operating levels with little or no corresponding increase in junction temperature, or an increased life and reliability for the device by conductive cooling with beryllia.
Influence of Sharp Notches on the Stress-Rupture Characteristics of Several Heat-Resisting Alloys
Authors: Brown W. F. , Jones M. H. , Newman D. P. 
Published: September 2009

Stress-rupture tests were carried out on a number of low-alloy steels, ferritic stainless steels and austenitic alloys. Both unnotched and sharply notched bars were tested at various temperatures. The ductilities were determined for both the unnotched and notched specimens.
It was found that all alloys tested were subject to notch weakening. The time and temperature range of this weakening effect and its magnitude varied greatly with the alloy composition. Tests carried out at 900, 1000, 1100, and 1200 F on a low alloy chromium-molybdenum-vanadium steel indicated the notch sensitivity to be time-temperature dependent. The general trends of the data conform to the conception that a precipitation reaction is responsible for the notch sensitivity.
No definite conclusions regarding notch-rupture sensitivity can be made by an examination of the data for the unnotched bars except possibly when this quantity is extremely low. The notch apparently can reduce the ductility of an otherwise ductile metal to the point where there is insufficient plastic flow to eliminate the initial stress concentration.
Retrograde Intraflagellar Transport Mutants Identify Complex A Proteins With Multiple Genetic Interactions inChlamydomonas reinhardtii
Authors: Iomini Carlo , Li Linya , Esparza Jessica M , Dutcher Susan K 
Published: September 2009

AbstractThe intraflagellar transport machinery is required for the assembly of cilia. It has been investigated by biochemical, genetic, and computational methods that have identified at least 21 proteins that assemble into two subcomplexes. It has been hypothesized that complex A is required for retrograde transport. Temperature-sensitive mutations in FLA15 and FLA17 show defects in retrograde intraflagellar transport (IFT) in Chlamydomonas. We show that IFT144 and IFT139, two complex A proteins, are encoded by FLA15 and FLA17, respectively. The fla15 allele is a missense mutation in a conserved cysteine and the fla17 allele is an in-frame deletion of three exons. The flagellar assembly defect of each mutant is rescued by the respective transgenes. In fla15 and fla17 mutants, bulges form in the distal one-third of the flagella at the permissive temperature and this phenotype is also rescued by the transgenes. These bulges contain the complex B component IFT74/72, but not α-tubulin or p28, a component of an inner dynein arm, which suggests specificity with respect to the proteins that accumulate in these bulges. IFT144 and IFT139 are likely to interact with each other and other proteins on the basis of three distinct genetic tests: (1) Double mutants display synthetic flagellar assembly defects at the permissive temperature, (2) heterozygous diploid strains exhibit second-site noncomplemention, and (3) transgenes confer two-copy suppression. Since these tests show different levels of phenotypic sensitivity, we propose they illustrate different gradations of gene interaction between complex A proteins themselves and with a complex B protein (IFT172).
Quantitative Genetic Bases of Anthocyanin Variation in Grape (Vitis viniferaL. ssp.sativa) Berry: A Quantitative Trait Locus to Quantitative Trait Nucleotide Integrated Study
Authors: Fournier-Level Alexandre , Le Cunff Loïc , Gomez Camila , Doligez Agnès , Ageorges Agnès , Roux Catherine , Bertrand Yves , Souquet Jean-Marc , Cheynier Véronique , This Patrice 
Published: September 2009

AbstractThe combination of QTL mapping studies of synthetic lines and association mapping studies of natural diversity represents an opportunity to throw light on the genetically based variation of quantitative traits. With the positional information provided through quantitative trait locus (QTL) mapping, which often leads to wide intervals encompassing numerous genes, it is now feasible to directly target candidate genes that are likely to be responsible for the observed variation in completely sequenced genomes and to test their effects through association genetics. This approach was performed in grape, a newly sequenced genome, to decipher the genetic architecture of anthocyanin content. Grapes may be either white or colored, ranging from the lightest pink to the darkest purple tones according to the amount of anthocyanin accumulated in the berry skin, which is a crucial trait for both wine quality and human nutrition. Although the determinism of the white phenotype has been fully identified, the genetic bases of the quantitative variation of anthocyanin content in berry skin remain unclear. A single QTL responsible for up to 62% of the variation in the anthocyanin content was mapped on a Syrah × Grenache F1 pseudo-testcross. Among the 68 unigenes identified in the grape genome within the QTL interval, a cluster of four Myb-type genes was selected on the basis of physiological evidence (VvMybA1, VvMybA2, VvMybA3, and VvMybA4). From a core collection of natural resources (141 individuals), 32 polymorphisms revealed significant association, and extended linkage disequilibrium was observed. Using a multivariate regression method, we demonstrated that five polymorphisms in VvMybA genes except VvMybA4 (one retrotransposon, three single nucleotide polymorphisms and one 2-bp insertion/deletion) accounted for 84% of the observed variation. All these polymorphisms led to either structural changes in the MYB proteins or differences in the VvMybAs promoters. We concluded that the continuous variation in anthocyanin content in grape was explained mainly by a single gene cluster of three VvMybA genes. The use of natural diversity helped to reduce one QTL to a set of five quantitative trait nucleotides and gave a clear picture of how isogenes combined their effects to shape grape color. Such analysis also illustrates how isogenes combine their effect to shape a complex quantitative trait and enables the definition of markers directly targeted for upcoming breeding programs.
Dissection of Genetic Factors Modulating Fetal Growth in Cattle Indicates a Substantial Role of the Non-SMC Condensin I Complex, Subunit G (NCAPG) Gene
Authors: Eberlein Annett , Takasuga Akiko , Setoguchi Kouji , Pfuhl Ralf , Flisikowski Krzysztof , Fries Ruedi , Klopp Norman , Fürbass Rainer , Weikard Rosemarie , Kühn Christa 
Published: September 2009

Abstract
The increasing evidence of fetal developmental effects on postnatal life, the still unknown fetal growth mechanisms impairing offspring generated by somatic nuclear transfer techniques, and the impact on stillbirth and dystocia in conventional reproduction have generated increasing attention toward mammalian fetal growth. We identified a highly significant quantitative trait locus (QTL) affecting fetal growth on bovine chromosome 6 in a specific resource population, which was set up by consistent use of embryo transfer and foster mothers and, thus, enabled dissection of fetal-specific genetic components of fetal growth. Merging our data with results from other cattle populations differing in historical and geographical origin and with comparative data from human whole-genome association mapping suggests that a nonsynonymous polymorphism in the non-SMC condensin I complex, subunit G (NCAPG) gene, NCAPG c.1326T&gt;G, is the potential cause of the identified QTL resulting in divergent bovine fetal growth. NCAPG gene expression data in fetal placentomes with different NCAPG c.1326T&gt;G genotypes, which are in line with recent results about differential NCAPG expression in placentomes from studies on assisted reproduction techniques, indicate that the NCAPG locus may give valuable information on the specific mechanisms regulating fetal growth in mammals.
Cross-Species RNAi Rescue Platform in Drosophila melanogaster
Authors: Kondo Shu , Booker Matthew , Perrimon Norbert 
Published: September 2009

Abstract
RNAi-mediated gene knockdown in Drosophila melanogaster is a powerful method to analyze loss-of-function phenotypes both in cell culture and in vivo. However, it has also become clear that false positives caused by off-target effects are prevalent, requiring careful validation of RNAi-induced phenotypes. The most rigorous proof that an RNAi-induced phenotype is due to loss of its intended target is to rescue the phenotype by a transgene impervious to RNAi. For large-scale validations in the mouse and Caenorhabditis elegans, this has been accomplished by using bacterial artificial chromosomes (BACs) of related species. However, in Drosophila, this approach is not feasible because transformation of large BACs is inefficient. We have therefore developed a general RNAi rescue approach for Drosophila that employs Cre/loxP-mediated recombination to rapidly retrofit existing fosmid clones into rescue constructs. Retrofitted fosmid clones carry a selection marker and a phiC31 attB site, which facilitates the production of transgenic animals. Here, we describe our approach and demonstrate proof-of-principle experiments showing that D. pseudoobscura fosmids can successfully rescue RNAi-induced phenotypes in D. melanogaster, both in cell culture and in vivo. Altogether, the tools and method that we have developed provide a gold standard for validation of Drosophila RNAi experiments.
Infrared Ellipsometry Investigation of Hydrogenated Amorphous Silicon
Authors: Gaspari Franco , Shkrebtii Anatoli , Tiwald Tom E. , Fuchser Andrea , Ahmed Shafiq Muhammad , Kosteski Tome , Leong Keith , Kherani Nazir 
Published: September 2009

AbstractHydrogenated amorphous silicon (a-Si:H) has been extensively investigated experimentally in the infrared spectral region via techniques such as Fourier Transform Infrared (FTIR) and Raman spectroscopy. Although spectroscopic ellipsometry has been proven to be an important tool for the determination of several parameters of a-Si:H films, including dielectric constant, surface roughness, doping concentration and layer thickness, the spectral range used in these studies has rarely covered the infrared region below 0.6 eV, and never over the complete spectral region of interest (0.04 – 0.3 eV).
We have measured for the first time the dielectric function of a-Si:H films grown by the
saddle field glow discharge technique by spectroscopic ellipsometry in the energy range from 0.04 eV to 6.5 eV, thus extending the analysis into the far infrared region. The a-Si:H films were deposited on germanium substrates for the ellipsometry studies, and on crystalline silicon substrates for the comparative FTIR analysis. Preparation parameters were chosen to obtain films with different hydrogen content. In this paper, we present the results of the ellipsometry analysis, evaluate different fitting techniques, and compare the results with the corresponding FTIR spectra. The similarities and differences between the spectra are discussed in terms of the a-Si:H properties.
Effect Of Trapping On Dielectric Conduction Mechanisms Of ULK/Cu Interconnects
Authors: Verrière Virginie , Guedj Cyril , Roy David , Blonkowski Serge , Sylvestre Alain 
Published: September 2009

AbstractTrapping in low-κ dielectric for interconnects was highlighted by voltage shift in IV current-voltage measurements. It is shown that effects of trapping can impact the extraction of conduction mechanisms. Capacitance measurements made on these materials reveal that trapping is at the origin in the increase of capacitance. The creation of dipoles because of this trapping explains this increase in the value of capacitance.
Dual Damascene Reactive Ion Etch Polymer Characterization through X-Ray Photoelectron Spectroscopy for 65 nm and 45nm Technology Nodes
Authors: Choi Samuel , Dziobkowski Chet , Tai Leo 
Published: September 2009

AbstractAt 65nm and beyond technology nodes, copper interconnect formation in dual damascene integration is continually challenged from a polymer management perspective. Highly polymeric plasma chemistry is required to reduce line edge roughness, shape physical profile, and control critical dimension across a 300mm wafer. But too much fluorocarbon deposition on a wafer results in poor defects yield.In this paper, X-ray photoelectron spectroscopy (XPS) characterization technique is used to quantify and to optimize a metal line reactive ion etch process to increase electrical opens yield. A reduction of 2 at.% in carbon mass results in a Do (defects/cm2) improvement from > 2.0 to less than 1.0. This result is realized without a shift to the trench physical profile which is important for reliability performance. Moreover, with a shorter turnaround time of XPS characterization compared to electrical hardware splits, quicker yield learning cycle is realized for both RIE process and module integration.
Characterization of Plasma Damage in Low-k Films by TVS Measurements
Authors: Ciofi Ivan , Baklanov Mikhail R. , Calbo Giovanni , Tőkei Zsolt , Beyer Gerald 
Published: September 2009

AbstractWe evaluated Triangular Voltage Sweep (TVS) measurements as a technique to characterize plasma damage in low-k films. Blanket wafers with low-k films of different porosity and k value were prepared. Our samples included an SiOC:H material with 7% porosity and k value of 3.0, deposited on 200mm wafers, and two SiOC:H materials with 25% porosity and k value of 2.5, deposited on 300mm wafers. Before deposition, a thin layer of dry thermal oxide (2 – 5 nm) was grown on the n-type wafers to stabilize the silicon interface. After deposition, low-k films were exposed to N2/H2 plasma for different times in order to induce different degree of plasma damage. Untreated low-k films were always included as a reference. For electrical measurements, metal dots were deposited on pieces to fabricate Metal-Insulator-Semiconductor capacitors.TVS measurements were performed at 190°C on the different samples. On samples exposed to N2/H2 plasma, we detected a current peak in the TVS trace, whose magnitude increased with exposure time to plasma. No peaks were detected on untreated films. This indicates that TVS measurements are sensitive to plasma damage. Furthermore, TVS results correlated well with FTIR spectra that showed increasing damage and H2O uptake with increasing exposure time to plasma. We conclude that TVS measurements are suitable for characterizing the degree of plasma damage in low-k films and complement well materials analysis, because with the help of TVS a link to leakage properties can be made. As an application, we used TVS measurements for evaluating restoration of plasma damaged low-k films by long N2-bake at high temperature. Wafer pieces from each sample were baked at 350°C for 4h30min in N2 atmosphere. A few pieces were measured immediately after baking. The remaining pieces were either left exposed to ambient for a few days or dipped in deionized H2O for a few hours to evaluate recovery of hydrophobic properties. The different treatments (N2-bake, exposure to ambient, H2O dipping) were always performed on blanket wafer pieces. Metal dots for electrical measurements were only deposited after the treatment. CV and FTIR measurements were performed before and after treatments to evaluate change in k-value and material structure, respectively. Our data show that long N2-bake at high temperature can partially restore damaged low-k films. The magnitude of the damage-related TVS peak was significantly reduced after heat treatment and remained stable even after H2O dipping. CV measurements performed on baked pieces after 6 days of exposure to ambient showed a reduced k-value. Consistently, FTIR spectra showed a significant reduction of H2O content soon after baking. The materials remained stable over several days and only minor reincorporation of H2O occurred after exposure to ambient or H2O dipping. Therefore, long N2-bake at high temperature can partially restore leakage (TVS), k-value (CV) and hydrophobic properties (FTIR) of damaged low-k films.
Coupled Finite Element–Potts Model Simulations of Grain Growth in Copper Interconnects
Authors: Radhakrishnan Bala , Sarma Gorti 
Published: September 2009

AbstractThe paper addresses grain growth in copper interconnects in the presence of thermal expansion mismatch stresses. The evolution of grain structure and texture in copper in the simultaneous presence of two driving forces, curvature and elastic stored energy difference, is modeled by using a hybrid Potts model simulation approach. The elastic stored energy is calculated by using the commercial finite element code ABAQUS, where the effect of elastic anisotropy on the thermal mismatch stress and strain distribution within a polycrystalline grain structure is modeled through a user material (UMAT) interface. Parametric studies on the effect of trench width and the height of the overburden were carried out. The results show that the grain structure and texture evolution are significantly altered by the presence of elastic strain energy.
Electronic Transport Properties of Cu/MnOx/SiO2/p-Si MOS Devices
Authors: Dixit Vijay Kumar , Neishi Koji , Koike Junichi 
Published: September 2009

AbstractAn ultrathin barrier layer of MnOx was grown using metal organic chemical vapor deposition (MOCVD) at an interface between Cu and SiO2 dielectric. The electronic transport properties of Cu/MnOx/SiO2/p-Si metal oxide semiconductor (MOS) devices showed leakage current density within the range of 10-8-10-7A/cm2 up to an electric field of 4MV/cm. The current density remained within the same range after bias temperature aging test at 3MV/cm for 6×103s at 550K. The capacitance-voltage curves of the MOS device having the MnOx layer grown at 473K do not show significant shift of flat band voltage after thermal annealing at 673K for 3.6×103s as well as after bias temperature aging test at 1MV/cm, 550K for 2.4×103 s. These results indicate that the ultrathin layer of MnOx is stable under the above conditions and prevents sufficiently Cu ion diffusion into the SiO2 dielectric.
A Novel X-ray Diffraction –based Technique for Complete Stress State Mapping of Packaged Silicon Dies
Authors: Raghothamachar Balaji , Sarkar Vishwanath , Noveski Vladimir , Dudley Michael , Sharan Sujit 
Published: September 2009

AbstractFundamental understanding of the silicon stresses and their changes with traditional wire-bonded and flip chip packages is critical to address the performance and reliability improvements in new technologies. Recently we have developed a novel technique for non-destructive measurements of complete strain state (and thereby the stress state) of the single crystal (bulk Si) by tracing the relative change in direction of an x-ray beam diffracted from a stressed crystal. This is based on the relationship between the stress state in a crystal and the local lattice plane orientation. Experimentally, this can be achieved by using a large area synchrotron white beam in conjunction with a precision grid of x-ray absorbing material placed in the path of the beam. The grid breaks the X-ray beam into an array of micro-beams that are diffracted by the single crystal sample to produce an integrated x-ray topograph on which the inverse grid image is distorted due to changes in the paths of diffracted microbeams i.e. an x-ray reticulograph is created. The distortions are a result of the variations in the diffracting lattice plane orientation produced by strain present in the crystal. By measuring this distortion on multiple topographs through the electronic package and applying the ray tracing principle, the entire strain state of the silicon can be calculated and mapped for the entire sample. We have carried out stress mapping of the silicon device in the package by applying this non-destructive and non-invasive technique.
Local Bonding Asymmetries in Ge-As-Se Glasses
Authors: Mammadov Eldar , Taylor Craig , Baker David , Bobela David , Reyes Arneyl , Kuhns Philip , Mehdiyeva Salima 
Published: September 2009

AbstractHigh magnetic fields up to 22 T have been applied to determine the local bonding asymmetries in the Ge2As2Se7 and Ge2As2Se5 glasses by 75As NMR. The results are analyzed using computer simulations of the line-shape. The asymmetry parameter η of the electric field gradient at arsenic sites in Ge2As2Se7 is found to be about 0.2, indicating that the dominant arsenic structural units in the composition are nearly axially symmetric pyramids. In the Ge2As2Se5 glass, however, the 75As NMR spectrum exhibits no well-resolved structure, revealing the existence of highly asymmetric sites. The experimental data are fitted using the previously obtained distribution of quadrupole coupling constants from pulsed 75As NQR experiments. These NMR simulations assume a broad distribution of the asymmetry parameter. The results are in agreement with the NQR studies in the same compositions.
Two-Junction GaAs/Ge Cells With Three Terminals for PV and CPV Applications
Authors: Emziane Mahieddine 
Published: September 2009

AbstractThe present investigation deals with a two-junction device having GaAs as the top cell and Ge for the bottom cell on a Ge substrate. Compared with the conventional two-terminal device configuration, three terminals avoid the loss due to current mismatching between the cells, and the resistance loss originating from the tunnel junction between the cells. Device structures were investigated and optimized with regard to the thicknesses and doping levels of both top and bottom active junctions that lead to the highest device performance. Due to the split of the incident solar spectrum between GaAs and Ge cells, the latter only receives the light to which the former is transparent (mainly in the near infrared) and therefore behaves differently from a single-junction Ge cell. Optimal current-voltage and power-voltage characteristics were generated for individual cells together with the corresponding device PV parameters. The predictions show that an extended spectral coverage is achieved leading to an enhanced overall power output from the devices. The potential applications of these devices in conventional as well as concentrator PV were assessed and discussed as a function of the simulated concentration ratio of the incident light under AM1.5 illumination conditions. We have shown that a relatively thin double-junction GaAs/Ge device can achieve a remarkably high power output.