bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabrication and Characterization of High Aspect Ratio Conducting Polymer Fibers
Authors: Saez Miguel A. , Montemayor Lauren , Pillai Priam Vasudevan , Hunter Ian W 
Published: August 2010

AbstractElectroactive conducting polymers are currently studied for use in smart textiles that incorporate sensing, actuation, control, and data transmission. The development of intelligent garments that integrate these various functionalities over wide areas (i.e. the human body) requires the production of long, highly conductive, and mechanically robust fibers. This study focuses on the electrical, mechanical and electrochemical characterization of high aspect ratio polypyrrole fibers produced using a novel, custom-built fiber slicing instrument. In order to ensure high conductivity and mechanical robustness, the fibers are sliced from tetra-ethylammonium hexafluorophosphate-doped polypyrrole thin films electrodeposited onto a glassy carbon crucible. The computer-controlled, four-axis slicing instrument precisely cuts the film into thin, long fibers by running a sharp blade over the crucible in a continuous helical pattern. This versatile fabrication process has been used to produce free-standing fibers with square cross-sections of 2 μm × 3 μm, 20 μm × 20 μm, and 100 μm × 20 μm with lengths of 15 mm, 460 mm, and 1,200 mm, respectively. An electrochemical dynamic mechanical analyzer built in-house for nano- and microfiber testing was used to perform stress-strain and conductivity measurements in air. The fibers were found to, on average, have an elastic modulus of 1.7 GPa, yield strength of 37 MPa, ultimate tensile strength of 80 MPa, elongation at break of 49%, and an electrical conductivity of 12,700 S/m. SEM micrographs show that the fibers are free of defects and have cleanly cut edges. Preliminary measurements of the fibers’ strain-resistance relationship have resulted in gage factors suitable for strain sensing applications. Initial tests of the actuation performance of fibers in neat 1-butyl-3-methylimidazolium hexaflourophosphate have shown promising results. These monofilament fibers may be spun into yarns or braided into 2- and 3-dimensional structures for use as actuators, sensors, antennae, and electrical interconnects in smart fabrics.
Nb2O5-based solar fabrics
Authors: Le Viet Anh , Jose Rajan , Ramakrishna Seeram 
Published: August 2010

AbstractPhoto active fibers containing dye anchored Nb2O5 nanorods, hole conduction and electron conduction materials were synthesized by the electrospinning technique. A 1.92 cm2 piece of fabric, composed of randomly aligned nanorods, was tested as a photovoltaic device under standard illumination conditions. The solar fabric exhibited an open circuit voltage (Voc) of ˜0.67 V, a short current density (JSC) of 4.77×10-4 mA/cm2, a fill factor (FF) of ˜15%, and an overall photovoltaic conversion efficiency (η) of 4.5×10-7%. This article presents for the first time the application of Nb2O5 in solar fabric.
Chemical Transport Deposition of Purified Poly-Si Films from Metallurgical-grade Si Using Subatmospheric-pressure H2 Plasma
Authors: Yasutake Kiyoshi , Ohmi Hiromasa , Kakiuchi Hiroaki 
Published: August 2010

AbstractPurified Si film is prepared directly from metallurgical-grade Si (MG-Si) by chemical transport using subatmospheric-pressure H2 plasma. The purification mechanism is based on the selective etching of Si by atomic H. Since most metals are not etched by H, this process is efficient to reduce metal impurities in Si films. It is demonstrated that the concentrations of most metal impurities (Fe, Mn, Ti, Co, Cr, Ni, etc.) in the prepared Si film are in the acceptable range for applying it to solar-grade Si (SOG-Si) material, or below the determination limit of the present measurements. On the other hand B and P atoms, which make volatile hydrogen compounds such as B2H6 and PH3, are difficult to eliminate by the present principle. From the infrared absorption measurements of the etching product produced by the reaction between H2 plasma and MG-Si, it is found that the main etching product is SiH4. Therefore, a remote-type chemical transport process is possible to produce SiH4 gas directly from MG-Si. Combining other purifying principle (such as a pyrolysis filter), this process may have an advantage to eliminate B2H6 and PH3 from the produced SiH4 gas.
A SAXS Study of Hydrogenated Nanocrystalline Silicon Thin Films
Authors: Kiriluk Kristin , Williamson Don , Bobela David , Taylor Craig , Yan Baojie , Yang Jeff , Guha Subhendu , Madan Arun , Zhu Feng 
Published: August 2010

AbstractWe have used small-angle x-ray scattering (SAXS) in conjunction with X-ray diffraction (XRD) to study the nanostructure of hydrogenated nanocrystalline silicon (nc-Si:H). The crystallite size in the growth direction, as deduced from XRD data, is 24 nm with a preferred [220] orientation in the growth direction of the film. Fitting the SAXS intensity shows that the scattering derives from electron density fluctuations of both voids in the amorphous phase and H-rich clusters in the film, probably at the crystallite interfaces. The SAXS results indicate ellipsoidal shaped crystallites about 6 nm in size perpendicular to the growth direction. We annealed the samples, stepwise, and then measured the SAXS and ESR. At temperatures below 350◦C, we observe an overall increase in the size of the scattering centers on annealing but only a small change in the spin density, which suggests that bond reconstruction on the crystallite surfaces takes place with high efficacy.
The Grain Size Distribution in Crystallization Processes With Anisotropic Growth Rate
Authors: Lokovic Kimberly S. , Bergmann Ralf B. , Bill Andreas 
Published: August 2010

AbstractThe grain size distribution allows characterizing quantitatively the microstructure at different stages of crystallization of an amorphous solid. We propose a generalization of the theory we established for spherical grains, to the case of grains with ellipsoidal shape. We discuss different anisotropic growth mechanisms of the grains in thin films. An analytical expression of the grain size distribution is obtained for the case where grains grow through a change of volume while keeping their shape invariant. The resulting normalized grain size distribution is shown to be affected by anisotropy through the time-decay of the effective growth rate.
Sub-gap Photoconductivity in Germanium-silicon Films Deposited by Low Frequency Plasma
Authors: Kosarev Andrey , Avila Francisco 
Published: August 2010

Abstract(GexSi1-x:H) films are of much interest for many device applications because of narrow band gap and compatibility with films deposited by plasma. However, electronic properties of GexSi1-x:H films for high Ge content x > 0.5 have been studied less than those of Si films. In this work, we present a study of sub-gap photoconductivity (σpc) in GexSi1-x:H films for x = 1 and x = 0.97 deposited by low frequency plasma enhanced chemical vapor deposition (LF PECVD) with both various H-dilution (RH) during growth (non-doped films) and boron (B) incorporation in the films. Spectra of sub-gap photoconductivity σpc(hν) were measured in the photon energy range of hν = 0.6 to 1.8 eV. σpc(hν) spectra were normalized to constant intensity. For hν < Eg two regions in σpc(hν) can be distinguished: “A”, where σpc is related to transitions between tail and extended states, and “B”, where photoconductivity is due to defect states. σpc(hν) in ”A” region showed exponential behavior that could be described by some characteristic energy EUPC similar to Urbach energy EU in spectral dependence of optical absorption. EUPC > EU was observed in all the films studied. This together with higher relative values (i.e. normalized by the maximum value at hν = Eg) for photoconductivity comparing with those for α means that mobility-lifetime product (μτ) depends on photon energy μτ = f(hν) that was determined from α(hν)and σpc(hν). μτ(hν) increases by factor of 20 to 40 depending on the sample with reducing hν from 1.1 to 0.7 eV. In some samples, this dependence was monotonous, while in others demonstrated maxima related to both interference and density of states. Effects of both RH and boron incorporation have been found and are discussed.
Thermoelectric properties of doped and undoped mixed phase hydrogenated amorphous/nanocrystalline silicon thin films
Authors: Kakalios James , Adjallah Yves , Blackwell Charlie 
Published: August 2010

AbstractThe Seebeck coefficient and dark conductivity for undoped, and n-type doped thin film hydrogenated amorphous silicon (a-Si:H), and mixed-phase films with silicon nanocrystalline inclusions (a/nc-Si:H) are reported. For both undoped a-Si:H and undoped a/nc-Si:H films, the dark conductivity is enhanced by the addition of silicon nanocrystals. The thermopower of the undoped a/nc-Si:H has a lower Seebeck coefficient, and similar temperature dependence, to that observed for undoped a-Si:H. In contrast, the addition of nanoparticles in doped a/nc-Si:H thin films leads to a negative Seebeck coefficient (consistent with n-type doping) with a positive temperature dependence, that is, the Seebeck coefficient becomes larger at higher temperatures. The temperature dependence of the thermopower of the doped a/nc-Si:H is similar to that observed in unhydrogenated a-Si grown by sputtering or following high-temperature annealing of a-Si:H, suggesting that charge transport may occur via hopping in these materials.
Mechanism for Improved Quality B12As2 Epitaxial Films on (0001) 4H-SiC Substrates by Tilting toward [1-100] Direction
Authors: Zhang Yu , Chen Hui , Dudley Michael , Zhang Yi , Edgar James , Gong Yinyan , Bakalova Silvia , Kuball Martin , Zhang Lihua , Su Dong , Kisslinger Kim , Zhu Yimei 
Published: August 2010

AbstractIn this work, 4H-SiC substrates intentionally misoriented from the (0001) plane toward [1-100] direction are shown to eliminate rotational twinning in icosahedral boron arsenide (B12As2, abbreviated here as IBA) epitaxial films. Previous studies of IBA on other substrates, including (100), (110), (111) Si and (0001) 6H-SiC, produced polycrystalline and twinned epilayers. Comparisons of IBA on on-axis and off-axis c-plane 4H-SiC by synchrotron white beam x-ray topography (SWBXT), and high resolution transmission electron microscopy (HRTEM) confirm the single crystalline and much higher quality of the films on the latter substrates. Furthermore, no intermediate layer between the epilayer and substrate was observed for IBA on off-axis 4H-SiC. Steps formed on the off-axis 4H-SiC substrate surface before deposition cause the film to adopt a single orientation, a process that is not seen with substrates with either no misorientation, or those tilted toward the [11-20] direction. This work demonstrates that c-plane 4H-SiC with 7° offcut toward (1-100) is potentially a good substrate choice for the growth of high-quality, untwinned B12As2 epilayers for future device applications.
Investigation of SiO2 Cap for Al Implant Activation in 4H-SiC
Authors: Zhao Feng , Islam Mohammad m , Chandrasekhar MVS , Sudarshan Tangali 
Published: August 2010

AbstractThe effect of using SiO2 capping layer during Al implant activation anneal on the performance of 4H-SiC P-i-N diodes has been investigated. Two sets of 4H-SiC pin diode samples, one with SiO2 cap and another with graphite cap, were annealed under high temperatures of 1500°C for activation after Al implantation at 650°C to form the p-type active region and the JTE region. The surface stoichiometry of annealed SiC was examined by x-ray photoelectron spectroscopy (XPS). Various material and device parameters including surface roughness, sheet resistance, minimum forward leakage current and maximum breakdown voltage have been extracted for comparison. The results show that SiO2 cap effectively protects the SiC surface during high temperature implant annealing.
Improved Inversion Channel Mobility in Si-face 4H-SiC MOSFETs by Phosphorus Incorporation Technique
Authors: Okamoto Dai , Yano Hiroshi , Kotake Shinya , Hirata Kenji , Hatayama Tomoaki , Fuyuki Takashi 
Published: August 2010

AbstractWe propose a new technique to fabricate 4H-SiC metal–oxide–semiconductor field-effect transistors (MOSFETs) with high inversion channel mobility. P atoms were incorporated into the SiO2/4H-SiC(0001) interface by post-oxidation annealing using phosphoryl chloride (POCl3). The interface state density at 0.2 eV from the conduction band edge was reduced to less than 1 × 1011 cm−2eV−1 by the POCl3 annealing at 1000 °C. The peak field-effect mobility of 4H-SiC MOSFETs on (0001) Si-face processed with POCl3 annealing at 1000 °C was approximately 90 cm2/Vs. The high channel mobility is attributed to the reduced interface state density near the conduction band edge.
The Mechanism of Haze and Defectivity Reduction in a New Generation of High Performance Silicon Final Polishing Slurries
Authors: White Michael L , Romine Richard , Jones Lamon , Ackerman William 
Published: August 2010

AbstractThe mechanism of haze reduction during silicon polishing using a new generation of additives has been explored. These additives are thought to decrease haze by adsorbing to the wafer surface and increasing the activation energy of the reaction between the silanolates on the silica particle surface with the surface silicon. This leads to greater selectivity between the peaks and valleys resulting in a net decrease in surface roughness.
Non-selective, High Removal Rates STI Slurries Based on Lewis Acids Abrasives/Cationic Copolymers
Authors: White Daniela , Parker John C , Nagarajan R 
Published: August 2010

AbstractIn this presentation we will discuss polishing performance and related mechanistic aspects of several low solids, low or high pH slurries based on Lewis acids abrasives (TiO2, ZrO2, CeO2), activated by cationic homopolymers, and copolymers with acrylic functionality. In a typical example, a formulation containing 0.5% ZrO2 interacting with 75 ppm cationic copolymer, at pH = 4, resulted in a SiO2 removal rate increase of 34% and a nitride removal rate increase of 97%, as compared with the control lacking the cationic copolymer. We will provide a complex variety of analytical evidence and particle and wafers surface measurements (FT-IR, GPC, surface energy) in order to support our mechanistic hypotheses. We will show with this unique system that 1:1 selectivities of oxide and nitride can be achieved with high removal rates.
Mechanistic Investigations of Ruthenium Polishing Enabled by Heterogeneous Catalysis With Titania-based Slurries
Authors: White Daniela , Parker John C , Nagarajan R 
Published: August 2010

AbstractDifficulties and challenges have been widely encountered in the chemical mechanical planarization (CMP) of noble metals used as diffusion barrier films due to hardness, chemical inertness and toxic oxidation products, in particular for Ru polishing. A commercial CMC Ru polishing slurry that successfully addressed the safety concerns was based on a high pH (8.4) polymer-treated-alumina-based multi-additive slurry containing complexing reagents (carboxylic acids and salts), corrosion inhibitors, surfactants, and hydrogen peroxide as a mild, non-aggressive oxidizer. Recently, our efforts had been redirected towards the development of a new generation of low pH barrier slurries based on an entirely new concept employing unique Lewis acid type abrasives. This class of materials is well known to be highly reactive in dielectrics polishing (ceria, zirconia, titania), but far less is known about their interactions with Ru, Cu or Ta.In this presentation, we will elaborate the unexpected discovery that hard, chemically inert, noble metals such as ruthenium can be polished easily by virtually abrasive-free and/or oxidizer-free TiO2 based slurries. Of particular importance is the finding that the polymorphic phase of TiO2 (anatase or rutile), its surface chemistry (functional groups, Lewis acid/base character), pH induced surface modification and reactivity, can all mediate the abrasive particle's adsorption properties, catalytic activity and ultimately, its slurry polishing performance.
Organometallic Chemical Liquid Deposition (OMCLD) of Cu/SiO2 Films for 3D Filling in Microelectronic Applications
Authors: Fau Pierre , Piettre Kilian , Latour Virginie , Margeat Olivier , Barrière Clément , Colliere Vincent , Anceau Christine , Quoirin Jean Baptiste , Chaudret Bruno 
Published: August 2010

AbstractThe copper precursor N,N'-diisopropylacetamidinate has been decomposed at low temperature (80-110°C) in a liquid process under a moderate H2 pressure. Depending on the choice of the solvent, the process leads to a colloidal solution of well controlled copper nanoparticles or the deposition of composite Cu-SiO2 films on the surfaces. The latter layer is highly adhesive to silica surface, behaves as an active seed layer for electroless copper deposition and allows a conformal covering inside deep trenches.
Copper-sulfide Passivation Capping for Cu Interconnects
Authors: Cohen Uri 
Published: August 2010

AbstractCopper-sulfide is proposed as a selective self-aligned passivation capping film on Cu lines, to improve the lines immunity against electromigration. Copper-sulfide is tenacious, having excellent adhesion (chemically bonded) to the underlying copper lines and strong adhesion to the overlying dielectric capping barrier. Contrary to other passivation schemes, Cu sulfidation is 100% selective. The sulfidation can be done by a wet or a dry process. A very thin copper-sulfide film (of about 25-100Å) will be required, and no significant increase of RC delay is expected.
Direct Measurement of Hot-spot Temperature in Flip-chip Solder Joints With Cu Columns Under Current Stressing using Infrared Microscopy
Authors: Chen Chih , Liang Yu Chun , Yao D. J. 
Published: August 2010

AbstractIn this study, the temperature map distribution in the Sn3.0Ag0.5Cu solder bump with Cu column under current stressing is directly examined using infrared microscopy. It is the radiance changes between the different materials of the surface that cause the unreasonable temperature map distribution. By coating a thin layer of black optical paint which is in order to eliminate the radiance changes, we got the corrected temperature map distribution. Under a current stress of 1.15 × 104 A/cm2 at 100℃C, the hot-spot temperature is 132.2℃ which surpasses the average Cu column temperature of 129.7℃C and the average solder bump temperature of 127.4 ℃. Thermomigration in solder may still occur under a large current stressing.
Theoretical Characterization of a Nanocrystal Layer for Nonvolatile Memory Applications
Authors: Leroy Yann , Armeanu Dumitru , Cordan Anne-Sophie 
Published: August 2010

AbstractOn the road to miniaturization, nanocrystal layers are promising as floating gate in nonvolatile flash memories. Although much experimental work has been devoted to the study of these new memory devices, only few theoretical models exist to help the experimentalists to understand the physical phenomena encountered and explain the behavior of the device.We have developed a model based on the geometrical and physical properties of the elementary structure of a nanocrystal flash memory,i.e.one nanocrystal embedded in an oxide between the channel and the gate electrodes. To obtain a fine analysis of the observed phenomena, several specific hypotheses have been taken into account. Concerning the channel, the contribution of the subbands is explicitly included. In the case of an electrode with a quasi-continuum of energy levels, we replace the continuum by equivalent sets of 2D subbands in order to be able to isolate the energy range that really contributes to the charging/discharging of the nanocrystal. The properties of the materials (bulk band structure, dielectric permittivity, …) can be easily set as well as the geometrical specifications of the elementary structure (nanocrystal radius, tunnel and control oxyde thicknesses, …).The behavior of a layer of nanocrystals is described according to a statistical approach starting from single nanocrystal results. This method allows us to take into account the fluctuations of geometrical parameters. Thus we are able to simulate various types of materials for the nanocrystals (Si, Ge, …), the oxide layer (SiO2, HfO2, …) and the electrodes, for both a single nanocrystal and layers of nanocrystals.
Analysis on Resistance Change Mechanism of NiO-ReRAM Using Visualization Technique of Data Storage Area With Secondary Electron Image
Authors: Kinoshita Kentaro , Makino Tatsuya , Takatoshi Yoda , Kazufumi Dobashi , Satoru Kishida 
Published: August 2010

AbstractBoth a low resistance state and a high resistance state which were written by the voltage application in a local region of NiO/Pt films by using conducting atomic force microscopy (C-AFM) were observed by using scanning electron microscope (SEM) and electron probe micro analysis (EPMA). The writing regions are distinguishable as dark areas in a secondary electron image and thus can be specified without using complicated sample fabrication process to narrow down the writing regions such as the photolithography technique. In addition, the writing regions were analyzed by using energy dispersive X-ray spectroscopy (EDS) mapping. No difference between the inside and outside of the writing regions is observed for all the mapped elements including C and Rh. Here, C and Rh are the most probable candidates for contamination which affect the secondary electron image. Therefore, our results suggested that the observed change in the contrast of the second electron image is related to the intrinsic change in the electronic state of the NiO film and a secondary electron yield is correlated to the physical properties of the film.
Fabrication and Current-Voltage Characteristics of Ni Spin Quantum Cross Devices with P3HT:PCBM Organic Materials
Authors: Kaiju Hideo , Kondo Kenji , Basheer Nubla , Kawaguchi Nobuyoshi , White Susanne , Hirata Akihiko , Ishimaru Manabu , Hirotsu Yoshihiko , Ishibashi Akira 
Published: August 2010

AbstractWe have proposed spin quantum cross (SQC) devices, in which organic materials are sandwiched between two edges of magnetic thin films whose edges are crossed, towards the realization of novel beyond-CMOS switching devices. In SQC devices, nanometer-size junctions can be produced since the junction area is determined by the film thickness. In this study, we have fabricated Ni SQC devices with poly-3-hexylthiophene (P3HT): 6, 6-phenyl C61-butyric acid methyl ester (PCBM) organic materials and investigated the current-voltage (I-V) characteristics experimentally and theoretically. As a result of I-V measurements, ohmic I-V characteristics have been obtained at room temperature for Ni SQC devices with P3HT:PCBM organic materials, where the junction area is as small as 16 nm × 16 nm. This experimental result shows quantitative agreement with the theoretical calculation results performed within the framework of the Anderson model under the strong coupling limit. Our calculation also shows that a high on/off ratio beyond 10000:1 can be obtained in Ni SQC devices with P3HT:PCBM organic materials under the weak coupling condition.
Ferroelectric and Ferromagnetic Properties of Co-doped BiFeO3 Thin Films
Authors: Barrionuevo Danilo G , Singh Surinder P , Katiyar Ram S , Tomar Maharaj S. 
Published: August 2010

AbstractMaterials which possess electrical and magnetic coupling are of great interest for novel devices. Bi(Fe1-xCox)O3 (BFCO) material system was synthesized by solution route for various compositions and thin films were prepared by spin coating on Pt (Pt/Ti/SiO2/Si) substrates. Structural properties of the films were investigated by x-ray diffraction and Raman spectroscopy. X-ray diffraction patterns confirms intense (110) in BiFeO3 and Bi(Fe1-xCox)O3 with rhombohedra distorted perovskite structure without impure phase. Bi(Fe1-xCox)O3 films show week ferroelectric polarization and ferromagnetism at room temperature. Ferroelectric and ferromagnetic coupling could be attributed to the elimination of oxygen vacancies and increased stress in the crystal structure by partial replacement of Fe2+ ion by Co2+ ion.