bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymerization of Fullerene in Solution with Free Electron Laser Irradiation
Authors: Iwata Nobuyuki , Iio Yasunori , Ando Shigo , Nokariya Ryo , Yamamoto Hiroshi 
Published: April 2011

ABSTRACTThe free electron laser (FEL) of 450 or 500 nm was irradiated onto the pressed C60powder in vacuum. The grains with μm-order were observed showing the colors of blue, purple, yellow, and white in optical microscope images. The Ag(2) derived mode around 1460 cm−1in Raman spectra was observed from the grain, indicating the polymerization. The 100 μm-length grain was obtained just after dissolving the FEL irradiated specimens into the toluene and evaporating it. In order to expand the scale of C60polymer grains and to obtain an amorphous C60polymer, the FEL irradiation was carried out in solution to reduce the directivity for polymerization. Although polymerization was not promoted in C60precipitation in supersaturated solution due to low density of C60, the precipitation grown with the liquid-liquid interfacial precipitation (LLIP) method showed the 1454 cm−1Ag(2) derived mode in addition to the peaks around 1460 cm−1in toluene. In m-xylene with LLIP method, in a whole area of C60pillar-grains, polymerization was confirmed by the Raman analysis.
An AlGaAs/InGaAs HEMT Grown on Si Substrate with Ge/GexSi1-x Metamorphic Buffer Layers
Authors: Chang Edward , Lin Yueh-Chin , Hsiao Yu-Lin , Hsieh Y.C. , Chang Chia-Yuan , Kuo Chien-I , Luo Guang-Li 
Published: April 2011

ABSTRACTAn AlGaAs/InGaAs HEMT grown on Si substrate with Ge/GexSi1−x buffer is demonstrated. The Ge/GexSi1−x metamorphic buffer layer used in this structure was only 1.0 μgm thick. The electron mobility in the In0.18Ga0.82 As channel of the HEMT sample was 3,550 cm2/Vs. After fabrication, the HEMT device demonstrated a saturation current of 150 mA/mm and a maximum transconductance of 155 mS/mm. The well behaved characteristics of the HEMT device on the Si substrate are believed to be due to the very thin buffer layer achieved and the lack of the antiphase boundaries (APBs) formation and Ge diffusion into the GaAs layers.
Epitaxial Growth of Single Crystalline Ge Films on GaAs Substrates for CMOS Device Integration
Authors: Chin Hock-Chun , Zhu Ming , Samudra Ganesh , Yeo Yee-Chia 
Published: April 2011

ABSTRACTWe report a novel chemical vapor deposition (CVD) process for epitaxial growth of Ge film on GaAs substrate. The resultant layer exhibits device level quality, as shown by high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, high-resolution X-ray diffraction (HRXRD). In addition, atomic force microscopy (AFM) scanning indicates low RMS surface roughness of 5 Å. Secondary ion mass spectrometry (SIMS) reveals negligible out-diffusion of Ga and As into the Ge epilayer. By employing silane passivation, Ge p-MOSFET with TaN/HfO2 gate stack was fabricated on Ge/GaAs heterostructure for the first time, showing excellent output and pinch-off characteristics. A GaAs channel n-MOSFET was also fabricated, using similar SiH4 treatment during gate stack formation. These results reveal a potential solution to integrate Ge p-channel and GaAs n-channel MOSFET for advanced CMOS applications.
Effect of Au Nanocrystals Embedded in Conductive Polymer on Non-volatile Memory Window
Authors: Seung Hyun Min , Lee Jong Dae , Han Byeong-Il , Lee Gon-Sub , Park Jea-Gun 
Published: April 2011

AbstractRecently, non-volatile polymer memories have been researched as a next generation of non-volatile memory because of its simple structure and easy fabrication process. We found that two types of non-volatile polymer memory have different I-V behavior. First Polymer non-volatile memory with metal / oxide / polymer / metal structure But Polymer non-volatile memory embedded Au Nano-crystal shows different I-V behavior. Polymer non-volatile memory shows NDR(Negative Differential Resistance) Region after threshold voltage and low to high current path at increasing positive and negative bias. We can observe NDR(Negative Differential Resistance) Region on Polymer non-volatile memory embedded Au Nano crystal. We fabricated devices three different type to confirm difference Polymer non-volatile memory with metal / polymer / metal structure, metal / oxide / polymer / metal structure and Au nano-crystal embedded Polymer non-volatile memory. First we fabricated Polymer non-volatile memory with metal / PVK(Poly-n-vinyl carbarzole) / metal structure. first type of device shows ohmic I-V behavior. Second type of polymer non-volatile memory has oxide layer between metal and polymer layer. Oxide layer made by O2 plasma treatment(100W RF power, 100SCCM O2 gas flow) after metal layer deposited. Second type of device has same structure as first device except oxide layer. Second type of device shows I-V behavior similar to Resistive Memory. Resistive non-volatile memory shows low to high current path at increasing positive bias and high to low current path at increasing negative bias. I-V behaviors of second device due to effect of oxide layer between metal and polymer layer. Third type of polymer non-volatile memory we embed Au nano-crystal layer in polymer layer. Au nano-crystal layer embedded by curing process. We deposit 5nm Au layer after spin coated PVK(Poly-n-vinyl carbarzole) layer and curing at 300¡É. We can observe NDR(Negative Differential Resistance) Region and different I-V behaviors with other type of device. Finally we fabricated polymer non-volatile memory embedded au nano-crystal by dispersion method to confirm effect of au nano-crystal. We report difference I-V behaviors polymer non-volatile memory with metal / polymer / metal structure and polymer non-volatile memory embedded au nano-crystals
Organic Field Effect Transistors Having Hundreds of Nanometers Long Channels
Authors: Shang Liwei , Liu Ming , Tu Deyu , Zhen Lijuan , Liu Ge , Liu Xinghua 
Published: April 2011

AbstractThis work studied systemically the device characteristics when the OFETs' channels turn into hundreds of nm. Standard planar OFETs have been fabricated using electronic beam lithography. Copper phthalocyanine is used as the semiconductor materials. When reduce the L to about 300 nm will lead an abrupt degradation of device performance. The ratio of Ion/Ioff turns from several hundreds into couple of tens. And when change the L to about 100 nm, the mobility turns from 10−2 cm2/Vs into 10m5 cm2/Vs, and the threshold voltage turns from about 12 V into 36 V. These abrupt changes are due to the changes of interface between active layer and insulator layer caused by the reducing the L to close to the grain size.
Synthesis of Functional Materials by Means of Nitriding in Salts of Al2O3–Al, Al2O3–Ti and Al2O3–Fe Cermets
Authors: Miranda-Hernández José G. , Refugio-Garcia Elizabeth , Rocha-Rangel Enrique 
Published: April 2011

ABSTRACTIn this work the synthesis of functional gradient materials (FGMs) through the nitriding in salts of previously fabricated cermets is carried out. The matrix for the preparation of the FGMs is made of an Al2O3-based cermet with a fine and homogeneous dispersions of metallic particles of Al, Ti and Fe, the final content of the metallic particles in the cermets is of 10 vol. %. These materials are synthesized by powders techniques, considering as variable of study the reinforcement metal in the cermet, previous to sinter, cylindrical samples of the corresponding cermet are uniaxially compacted using 200 MPa. Subsequently, all sintered cermets are characterized by microstructural observations with the help of light microscopy. Obtained cermets are then submitted to a nitriding process by immersion in ammoniac salts. The objective is to attain a compositional gradient of metal-nitrides at the surface. This is done through a chemical reaction between the metallic particles at the cermets' surface and the nitrogen released by the ammonia salts. Functional materials are obtained such as; Al2O3–Al–AlN and Al2O3–Ti–TiN.
Alumina Extraction from Mexican Fly Ash
Authors: López-Cuevas Jorge , Long-González David , Gutiérrez-Chavarría Carlos A. , Rodríguez-Galicia José L. , Pech-Canul Martín I. 
Published: April 2011

ABSTRACTTwo alternative chemical methods are studied for the extraction of Al2O3 from Mexican Fly Ash (FA). Reaction of FA with H2SO4 at high temperature allows extracting ∼37% of the total Al2O3 contained in the FA as Al2(SO4)3, regardless of H2SO4 concentration, treatment time and temperature employed. This is partly due to the high chemical resistance of mullite (Al6Si2O13) contained in the FA. In contrast, reaction of FA with a CaCO3-Na2CO3 mixture at 1300°C/1h, followed by lixiviation with a Na2CO3 aqueous solution and precipitation of bohemite [AlO(OH)] by addition of either H2O2 or NH4HCO3, allows extracting ∼80% of the total Al2O3 contained in the FA as θ-alumina, after calcination of bohemite at 1200°C/1h.
Hot deformation behavior of low carbon advanced high strength steel (AHSS) microalloyed with boron
Authors: Mejía I. , González-Sala S. , Cabrera J.M. 
Published: April 2011

ABSTRACTThis research work deals the influence of boron content on the high temperature deformation behavior of a low carbon advanced high strength steel (AHSS). For this purpose high temperature tensile and compression tests are carried out at different temperatures and constant true strain rates by using an Instron testing machine equipped with a radiant cylindrical furnace. Tensile tests are carried out at different temperatures (650, 750, 800, 900 and 1000°C) at a constant true strain rate of 0.001 s-1. Uniaxial hot compression tests are also performed over a wide range of temperatures (950, 1000, 1050 and 1100°C) and constant true strain rates (10-3, 10-2 and 10-1 s-1). In general, experimental results of hot tensile tests show an improvement of the hot ductility of the AHSS microalloyed with boron, although poor ductility at low temperatures (650 and 750°C). The fracture surfaces of the AHSS tested at temperatures showing the higher ductility (800, 900 and 1000°C) indicate that the fracture mode is a result of ductile failure, whereas in the region of poor ductility the fracture mode is of the ductile-brittle type failure. On the other hand, experimental results of hot compression tests show that both peak stress and peak strain tend to decrease in the AHSS microalloyed with boron, which indicates that boron generates a sort of solid solution softening effect in similar a way to other interstitial alloying elements in steel. Likewise, hot flow curves of the AHSS microalloyed with boron show an acceleration of the onset of dynamic recrystallization (DRX) and a delay of the recrystallization kinetics. Results are discussed in terms of boron segregation towards austenitic grain boundaries and second phase particles precipitation during plastic deformation and cooling.
Nanostructures Detected by Conductvity Spectroscopy
Authors: Funke K. , El—egili K. , Reichelt R. , Amrein M. , Cramer C. 
Published: April 2011

ABSTRACTMeasurement of frequency dependent ionic conductivities is shown to be a simple and effective means for the detection and characterization of nanostructures in solid electrolytes. As an example, the conclusions drawn from the conductivity spectrum of a silveriodide/silver-borate glass are compared with scanning electron and scanning tunneling micrographs. The results consistently prove the existence of nanoscale heterogeneities about 25 nm in diameter.
Low Voltage Point Projection Microscopy and Time of Flight Stm - Two New Microscopies
Authors: Spence J.C.H. , Qian W. , Lo W. , Mo S. , Knipping U. , Zhang X. 
Published: April 2011

ABSTRACTThe design of a low voltage point-projection field-emission transmission electron microscope is described and images showing 0.7nm resolution at 100 volts are given. A scheme for low voltage reflection electron holography from bulk samples in UHV is outlined. A new STM is described which allows atomic clusters to be transferred onto the tip, then introduced into a time-of-flight analyser for species identification.
Trends in Atomic Resolution Electron Microscopy
Authors: Smith David J. , Mccartney M.R. 
Published: April 2011

ABSTRACTStructural information on the atomic scale is readily accessible from thin samples using the technique of high-resolution electron microscopy. Electron micrographs recorded under well-defined operating conditions can be directly interpreted in terms of atomic arrangements around defects of interest such as dislocations and interfaces. Digital image recording with slow-scan CCD cameras and quantitative comparisons with image simulations based on structural models are starting to lead to improved accuracy and reliability in structure determinations. Techniques based upon holographic methods are utilizing the superior illumination coherence of the field emission electron source to enhance resolution beyond the conventional extended Scherzer limit. Innovative methods for combining image and diffraction pattern information are also leading to improved levels of resolution for periodic objects. Care is needed to ensure that electron irradiation damage and surface cleanliness do not impose unnecessary restrictions on the details that can be extracted from recorded micrographs. It is proposed that the complex wavefunction emerging from the exit-surface of the sample should be considered as a basis for comparing the differences between experimental micrographs and image simulations.
Geometric Characterization of Electromigration Voids
Authors: Kime Yolanda J. , Grach Peter 
Published: April 2011

ABSTRACTThe areas, perimeters, lengths, and widths of 998 electromigration induced voids on 38 test stripes have been measured by SEM and digital image analysis. Virtually all of the voids occurred along the passivation-conductor interface on the side of the stripe. Plots of number of voids or total void area versus time to failure do not extrapolate to zero voids at zero time to failure which suggests there is a certain number of active nucleation sites predisposed to voiding.
Electromigration Damage in Conductor Lines: Recent Progress in Microscopic Observation and Mechanistic Modelling
Authors: Arzt E. , Kraft O. , MÖckl U.E. 
Published: April 2011

ABSTRACTIn this paper an overview of recent developments in understanding electromigration damage mechanisms is given. Based on our detailed studies, both ex-situ and in-situ, of damage in unpassivated near-bamboo lines, we develop a theoretical electromigration damage map. It explains why “slit-like” failure becomes predominant for narrow lines and low current densities. The mechanism of slit formation is discussed in the light of new analytical and numerical simulations of pore shape changes, which take stress effects into account. Possible implications for the rational design of improved metallization alloys are suggested.
Real-Time Thermo-Mechanical and Adhesive Property Evaluation of Thin Films and Multi-Layers
Authors: Rogers John A. , Nelson K. A. 
Published: April 2011

ABSTRACTWe describe an experimental method useful for in-situ real-time evaluation of viscoelastic, thermal and adhesive properties of thin films and multi-layer structures. We demonstrate how the technique is used to quantify the elastic moduli, and in-plane thermal diffusivity. We also show how it can be used to “spot check” for dis-bonds and to generate dis-bond “maps”.
Adhesion Strength of Cu/Polyimide Interfaces by Micro-Wedge Scratching
Authors: Wang F. , Nelson J.C. , Huang H. , Swisher R. L. , Gerberich W.W. 
Published: April 2011

ABSTRACTThe micro-wedge scratch technique was applied to characterize interfacial properties of copper fine lines on PMDA-ODA polyimide. A 20 pm wide, 0.1 μm radius wedge-shapeddiamond tip was used to mechanically debond Cu fine lines from polyimide substrate. Copper fine lines varies from 0.2 to 0.4 μm thick, and from 1.μm to 100 μm wide. Both cohesive and adhesive delaminations were obtained. Loaddisplacement curves were recorded and the scratch morphologies were observed by SEM. From a first order calculation, the fracture toughness of the polyimide and interfacial strength of Cu-PI were obtained.
Epitaxy of YBa2Cu3O7-xon Silicon on Sapphire: Possibilities and Limits
Authors: Copetti C. A. , Wang F. , Schubert J. , Schulz H. , Zander W. , Buchal Ch. 
Published: April 2011

AbstractWe present investigations of YBa2Cu3O7-x, thin films deposited on Silicon on Sapphire (SoS) substrates by pulsed laser deposition and dc sputtering. A compound buffer system consisting of YSZ and CeO2 is used for improved YBa2Cu3O7-x growth characteristics. The critical thickness of YBa2Cu3O7-x on CeO2/YSZ/SoS is determined to be 280 nm.
Epitaxial Oxide Films
Authors: Geballe Theodore H. 
Published: April 2011

AbstractSome perspective concerning the capabilities and potential of epitaxial oxide films is gained by comparison with the field of semiconductor epitaxy. The specific epitaxial behavior of MgO, (ZrY)O2, and the layered cuprates is discussed. A suggestion is given for a method of searching for higher temperature superconductors by the use of epitaxial indusions in layered structures.
Structure and Magnetic Properties of Epitaxial NiFe2O4 Films
Authors: Dover R. B. van , Venzke S. , Gyorgy E. M. , Siegrist T. , Phillips J. M. , Marshall J. H. , Felder R. J. 
Published: April 2011

AbstractWe have made NiFe2O4 films by rf sputtering using the 90 °off-axis geometry. Films grown at 600°C on SrTiO3 and Y.15Zr.85O2 substrates are single crystals with (100) and (110) texture, respectively, but exhibit a very large and unexpected random anisotropy. A postdeposition air anneal at ˜1000°C has little effect on the crystallinity of the films but almost completely eliminates the random anisotropy; the remaining anisotropy is consistent with expected (bulk) values. A decrease of the saturation magnetization, indicating degradation, was observed for films on SrTiO3 (but not Y.15Zr.85O2) annealed at 1300°C.
Common Themes in ther Epitaxial Growth of Oxides on Semiconductors
Authors: Tarsa E. J. , Mccormick K. L. , Speck J. S. 
Published: April 2011

AbstractA review of the growth of oriented oxides on Si and Ill-V semiconductors provides insight into some of the common themes of oxide/semiconductor epitaxy. The nature and success of the epitaxy can be attributed to four primary factors: (i) semiconductor surface preparation; (ii) oxide/semiconductor reaction thermodynamics; (iii) surface and interfacial polarity; and (iv) structural matching (lattice matching, thermal expansion, and symmetry). Semiconductor surface preparation governs the initial stages of epitaxy for systems such as MgO/GaAs and In2O3/InAs. In these cases, the epitaxial development depends on the presence or absence of a native oxide layer prior to growth. Chemical reaction can also influence the epitaxial process, as is illustrated in the growth of gadolinium oxide on Si. In general, the initial stages of epitaxy reflect a thermodynamic competition between the formation of the desired oxide phase, oxidation of the semiconductor, and formation of intermediate phases such as silicides and silicates. An analysis of possible reactions is presented for selected binary and ternary oxides with Si and GaAs. Surface and interfacial energy can also play an important role in determining the morphology and orientation of oxides having polar low-index faces, as illustrated in the growth of fluorite and related bixbyite oxides such as CeO2, In2O3and Y2O3. The epitaxial relationships between the oxide and semiconductor may be rationalized in terms of either direct lattice matching or higher order epitaxy.
Investigation of Titanium Silicide Formation Using Secondary Ion Mass Spectrometry
Authors: Wee Andrew T.S. , Huan Alfred C.H. , Thian W.H. , Tan K.L. , Hogan Royston 
Published: April 2011

ABSTRACTSecondary ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS) are used to investigate Ti silicide formation mechanisms on a series of Ti on Si thin films annealed in ultrahigh vacuum (UHV) at different temperatures and durations. The competition between oxygen diffusion and the silicide formation reaction (the socalled “snowplough” effect) is observed directly, as well as a Ti-Si-O layer. The results from these controlled experiments are compared with those from Ti silicide films formed under rapid thermal annealing (RTA) conditions in a production furnace, with and without a TiW barrier layer.
Speckle Techniques for Noncontact Temperature Measurement
Authors: Burckel D. , Zaidi S. H. , Lang M. K. , Frauenglass A. , Brueck S. R. J. 
Published: April 2011

ABSTRACTTwo complementary speckle techniques for the measurement of temperature from the rough back surface of Si wafers during rapid thermal processing are demonstrated. Electronic speckle pattern interferometry is a full field intensity cross-correlation technique that provides a two-dimensional map of the surface temperature. Measurements are presented that demonstrate a resolution of ∼ ±2°C. A new speckle technique, sub-feature speckle interferometry is introduced. This technique provides a much more rapid and precise averaged temperature measurement by monitoring the strain between two points with interferometric precision usually associated with moird interferometry or holography rather than speckle. Preliminary measurements are presented that demonstrate the capability of the technique.
Selective Epitaxial Silicon and Selective Titanium Silicide in an Industrial Integrated Cluster Tool
Authors: Regolini J. L. , Margail J. , Morin C. , Gouy-Pailler P. 
Published: April 2011

ABSTRACTIntegrated processes for IC manufacturing are today of prime importance for obtaining such high performance results as uniformity on large diameter wafers, reproducibility, throughput and reliability. Using an industrial integrated cluster reactor we have obtained selective epitaxial Si and selective TiSi2 deposition. This is a 200 mm reactor in which epitaxial silicon has been obtained with <1% (1σ) thickness uniformity and <2% over a 25 wafer batch. Full selectivity of Si on oxide has been obtained below a 20 Torr working pressure using the DCS/H2 gas system. No loading effect has been detected. The main characteristics of this system are described with the most relevant results like: sharp interfaces obtained in Si0.7Ge0.3/Si multilayer structures grown at 650°C, abruptly doped epitaxial layers and residual defect density.TiSi2 has been selectively obtained with minimum substrate consumption using the H2/SiH4 (or DCS)/TiC14 chemistry. The elevated source & drain has also been successfully tested by selective Si epitaxy followed by “in situ” selective TiSi2 deposition to compensate for substrate consumption.
Optical, Electrical, and Mechanical Characterization of Rapid Thermal Oxidation
Authors: Yarling C. B. , Keenan W. A. 
Published: April 2011

ABSTRACTIn this study, 6-150mm p-type <100> wafers were cleaned, laser-scribed, and pre-process measured for stress. The wafers were then processed in a tungsten-halogen lamp RTP system with a target Rapid Thermal Oxidation (RTO) thickness of 100Å. Three categories of whole-wafer measurement techniques were used to characterize these wafers: optical, electrical, and mechanical. Optical inspection techniques included spectroscopic reflectometry (reflectivity), and a combination of beam profile reflectometry and beam profile ellipsometry (thickness). Electrical techniques included C-V plotting with a mercury probe (oxide thickness from Cmax, breakdown voltage, and interface trap density) as well as laser-induced photo-current scanning (minority carrier lifetime, minority-carrier diffusion-length). Mechanical inspection included wafer warpage and stress measurements as well as optical imaging inspection using the magic mirror method (damage and defects). Wafer measurements from these instruments (i.e., contour and 3-d maps) are used to characterize integrity of the RTO process.