bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent Developments in SiC Homoepitaxy Using Dichlorosilane for High Power Devices
Authors: Chowdhury Iftekhar , Chandrasekhar MVS , Klein Paul B , Caldwell Joshua D , Sudarshan Tangali 
Published: August 2010

AbstractThick and high quality 4H-SiC epilayers have been grown in a vertical hot-wall chemical vapor deposition system at a high growth rate on (0001) 80off-axis substrates. We discuss the use of dichlorosilane as the Si-precursor for 4H-SiC epitaxial growth as it provides the most direct decomposition route into SiCl2, which is the predominant growth species in chlorinated chemistries. The RMS roughness of the films ranged from 0.5-2.0 nm with very few morphological defects (carrots, triangular defects, etc.) being introduced, while enabling growth rates of 30-100 μm/hr, 5-15 times higher than most conventional growths. A specular surface morphology was attained by limiting the hydrogen etch rate until the system was equilibrated at the desired growth temperature. Site-competition epitaxy was observed over a wide range of C/Si ratios, with doping concentrations as low as 2x1014cm-3being recorded. X-ray rocking curves indicated that the epilayers were of high crystallinity, with linewidths as narrow as 7.8 arcsec being observed, while microwave photoconductive decay (μPCD) measurements indicated that these films had high injection (ambipolar) carrier lifetimes in the range of 2 μs. These films also appeared to be free of polytype inclusions.
Single-crystal Silicon Carbide: A Biocompatible and Hemocompatible Semiconductor for Advanced Biomedical Applications
Authors: Saddow Stephen E. , Coletti Camilla , Frewin Christopher , Schettini Norelli Castro , Oliveros Alexandra , Jaroszeski Mark 
Published: August 2010

AbstractCrystalline silicon carbide (SiC) and silicon (Si) biocompatibility was evaluatedin vitroby directly culturing three skin and connective tissue cell lines, two immortalized neural cell lines, and platelet-rich plasma (PRP) on these semiconducting substrates. The experiments were performed specifically for the three adopted SiC polytypes, namely 3C-, 4H- and 6H-SiC, and the results were compared to those obtained for Si crystals. Cell proliferation and adhesion quality were studied using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays and fluorescent microscopy. For the neural cells studied AFM was also used to quantify the filopodia and lamellipodia extensions on the surface of the tested materials. Fluorescent microscopy was also used to assess platelet adhesion to the semiconductor surfaces where significantly lower values of platelet adhesion to 3C-SiC was observed compared to Si. The reported results show that SiC is indeed a more biocompatible substrate than Si. While there were some differences among the degree of biocompatibility of the various SiC polytypes tested, SiC appears to be a highly biocompatible materialin vitrothat is also somewhat hemocompatible. This extremely intriguing result appears to put SiC into a unique class of materials that is both bio- and hemo-compatible and is, to the best of our knowledge, the only semiconductor with this property.
Interconnect Technologies for Heterogeneous 3D Integration : CMOS and MEMS
Authors: Yang Hyung Suk , Bakir Muhannad 
Published: August 2010

AbstractMicroelectromechanical Systems (MEMS) market is a rapidly growing market with a wide range of devices. Most of these devices require an interaction with an electronic circuit, and with the increasing number of high performance MEMS devices that are being introduced, a demand for integrating CMOS and MEMS using high-density and low-parasitic interconnects have also been on the rise.Unfortunately, conventional methods of integrating CMOS with MEMS cannot provide the high density and low-parasitic interconnections required by modern high performance MEMS devices, and at the same time provide the flexibility required to accommodate new devices that are made using new materials and highly innovative fabrication processes.Heterogeneous 3D integration of MEMS and CMOS has the potential to provide both the performance and the integration flexibility; however there are two interconnect challenges that need to be addressed. This paper outlines the details of these interconnect challenges and introduces two interconnect technologies, Mechanically Flexible Interconnects (MFI) and Through-Silicon Via (TSV), developed specifically to address these challenges.
Fluxless Bonding Using Vacuum Ultraviolet and Formic Acid for 3D Interconnects
Authors: Sakuma Katsuyuki , Unami Naoko , Shoji shuichi , Mizuno Jun 
Published: August 2010

AbstractWe have developed a novel surface treatment process using vacuum ultraviolet (VUV) light with a wavelength of 172 nm and formic acid vapor. A previous study showed that the VUV process can help remove the organic contaminants on the bonding surfaces and improve the shear strength. This new work focuses on studying the effects of VUV/O3and formic acid treatments. The formic acid (HCOOH) vapor removes the metal oxides from the surfaces before the bonding process. Evaporated Cu/Sn and immersion Au were used for the bonding micro-bumps and bonding pads in our evaluations. Different cleaning conditions with VUV/O3, formic acid vapor, or both were compared and evaluated. X-ray Photoelectron Spectroscopy (XPS) was used to study the surface elemental composition of the micro-bumps and pad surfaces before and after the cleaning process. The photoelectron spectra of C1s, Sn3d, and Au4f were obtained with XPS. The XPS results showed the atomic carbon concentrations were significantly decreased by the VUV/O3treatment process, while the Sn and Au concentrations were increased by the VUV/O3and formic acid treatment because of the removal of the organic contaminants and metal oxides from the surfaces. The bonding strength of the Cu/Sn bumps was evaluated using a shear test tool. The results shows that the combination of VUV/O3and formic acid treatment obtains the highest average shear strength among the treatments tested, with a shear strength almost 2.5 times stronger than the untreated samples.
A Three Dimensional Self-folding Package (SFP) for Electronics
Authors: Gracias David , Cho Jeong-Hyun , Hu Steve 
Published: August 2010

AbstractWe describe the concept of a 3D self-folding package (SFP) for sensors and electronic devices. The strategy is based on a self-assembly strategy wherein 2D panels interconnected with hinges spontaneously fold-up when they are released from the substrate; self-folding can be triggered by temperature or selected chemicals. The strategy enables packaging of devices in porous polyhedral geometries that can either be untethered or substrate-bound. Self-folding can enable packaging of devices in small 3D form factors and may enable efficient cooling due to porosity. The utilization of this self-folding platform to enable 3D packaging of cantilever sensors and magnetic field sensitive strain gauges is summarized.
Small Organic Molecules for Electrically Re-writable Non-volatile Polymer Memory Devices
Authors: Salaoru Iulia , Paul Shashi 
Published: August 2010

AbstractThe usage of organic materials in the manufacture of electronic polymer memory devices is on the rise. Polymer memory devices are fabricated by depositing a blend (an admixture of organic polymer, small molecules and nanoparticles) between two metal electrodes. The primary aim is to produce devices that exhibit two distinct electrical conductance states when a voltage is applied. These two states can be viewed as the realisation of non-volatile memory. This is an interesting development; however, there are a number of theories that have been proposed to explain the observed electrical behaviour. We have proposed a model that is based on electric dipole formation in the polymer matrix. Here, we investigate further the proposed model by deliberately creating electric dipoles in a polymer matrix using electron donors (8-Hydroxyquinoline, Tetrathiafulvalene and Bis(ethylenedithio)tetrathiafulvalene) and electron acceptors (7,7,8,8-Tetracyanoquinodimethane, Tetracyanoethylene and Fullerene) small molecules.Two types of structures were investigated (i) a metal/blend of polymer and small molecules/metal (MOM), device and (ii) a metal/insulator/blend of small molecules and polymer/semiconductor (MIS) architecture. A blend of polymer and small organic molecules was prepared in methanol and spin-coated onto a glass substrate marked with thin aluminium (Al) tracks; a top Al contact was then evaporated onto the blend after drying - this resulted in a metal-organic-metal structure. The MIS structures consisted of an ohmic bottom Al contact, p-type Si, a polymer blend (two small organic molecules and insulating polymer), followed by polyvinyl acetate and finally a top, circular Al electrode. In-depth FTIR studies were carried out to understand the observed electrical behaviour. An electrical analysis of these structures was performed using an HP4140B picoammeter and an HP 4192A impedance analyser at a frequency of 1 MHz.
High-temperature Process Endurance of Oxide/Electrode Stacking Structure for Resistance Random Access Memory
Authors: Shima Hisashi , Nakano Takashi , Akinaga Hiro 
Published: August 2010

AbstractThe systematic investigation on the thermal stability of the CoO layer was carried out for various electrode materials. When Pt with higher oxygen potential (Gibbs free energy change of the oxidation reaction) compared to Co is used as electrodes, the resistance of the Pt/CoO/Pt devise was severely decreased by the post deposition annealing (PDA) process and the resistance switching into the high resistance state was observed in the first voltage sweep. This indicants that the reducing Ar ambient induces the quite local reduction of CoO. The reduction of the CoO layer is also expected even with the Co electrode, which is reasonably attributed to the oxygen concentration gradient at the Co/CoO interface in the Co/CoO/Pt device. With the Ti electrode having a much lower oxygen potential than Co, the reduction of CoO by Ti is also indicated electrically in the Pt/CoO/Ti device. On the other hands, W electrodes which is thought to have the solid-solution oxygen can stabilize the CoO layer during PDA although W is more affinitive with oxygen compared with Co. It can be pointed out the oxygen delivery at the electrode/oxide layer interface is a critical factor in designing the thermally stable stacking structure for resistance random access memory.
Electrical Characteristics of Crystalline Gd2O3 Film on Si (111): Impacts of Growth Temperature and Post Deposition Annealing
Authors: Niu Gang , Vilquin Bertrand , Baboux Nicolas , Saint-Girons Guillaume , Plossu Carole , Hollinger Guy 
Published: August 2010

AbstractThis work reports on the epitaxial growth of crystalline high-k Gd2O3 on Si (111) by Molecular Beam Epitaxy (MBE) for CMOS gate application. Epitaxial Gd2O3 films of different thicknesses have been deposited on Si (111) between 650°C~750°C. Electrical characterizations reveal that the sample grown at the optimal temperature (700°C) presents an equivalent oxide thickness (EOT) of 0.73nm with a leakage current density of 3.6×10-2 A/cm2 at |Vg-VFB|=1V. Different Post deposition Annealing (PDA) treatments have been performed for the samples grown under optimal condition. The Gd2O3 films exhibit good stability and the PDA process can effectively reduce the defect density in the oxide layer, which results in higher performances of the Gd2O3/Si (111) capacitor.
Study of Tunability of BST With Different Structures for Microwave Applications
Authors: El-Shaarawy Heba Badr El-Din , Pacchini Sebastien , Ouagague Badreddine , Payan Sandrine , Rousseau Anthony , Maglione Mario , Plana Robert 
Published: August 2010

AbstractThis paper addresses the characterization of the ferroelectric Ba0.6Sr0.4TiO3 on different substrates using three different microwave components. First, at low frequencies, metal-insulator-metal (MIM) capacitors are used to investigate the variation of the BST dielectric constant and loss tangent for different biasing voltages. BST shows a variation for the dielectric constant from 380 to 130, recording a tunability range of 66 %, and loss tangent of 0.027 to 0.005. In the range of frequency from 1 to 40 GHz, coplanar waveguides (CPW) are used to investigate the effective dielectric constant of BST on four different substrates, HR silicon substrates covered by silicon dioxide, silicon covered by silicon dioxide and silicon nitride, magnesium oxide (MgO (100)), and R-plane sapphire (Al2O3) substrate, all covered with 350 nm BST layer. The effective dielectric constant over silicon substrates covered by silica and BST is 7.2, 6.3 for Al2O3 substrates and 5.8 for MgO; and for the loss tangent, Al2O3 and MgO give about 0.03, while silicon substrates suffer higher values of 0.08 to 0.25. Finally, to study the tunability of microwave structures on the investigated substrates, interdigital capacitors (IDC) are fabricated and measured for different biasing voltages ranging from 0 to 55 V. IDCs over MgO show a tunability of 8.3%, while IDCs over sapphire show 20%.
Percolation Conduction of Nanoclusters Films for Nano-devices
Authors: Kang Il-Suk , Ahn Chi Won 
Published: August 2010

AbstractElectrical conduction of metal nanoclusters by percolation is a very interesting area in nano-device. For more functional nano-sensors consisting of multiple nanocluster blending film, various metals, such as Cu and Ni nanocluster films were fabricated using inert-gas condensation method. The percolation threshold of the films was measured. In addition, for the operation of sensors using these nanocluster films in air, aging experiments of the percolated films in air were carried out. While the percolation threshold was in connection not with the material species but with the area coverage of nanocluster films, the conductive characteristics according to the aging temperature depended on the material species. Reversible and irreversible conduction behaviors of nanocluster films were investigated with nanoscale microstructures using electron microscopes.
Multifunctional Nanoparticles for Targeted Imaging and Therapy of Cancer
Authors: Koo Lee Yong-Eun , Kopelman Raoul 
Published: August 2010

AbstractThe idea of making biocompatible multifunctional nanoparticles, combining therapy, imaging and targeting, was aimed at cancer from the start a dozen years ago. This presentation will emphasize targeted theranostic nanoparticles, where “theranostic” literally means combining therapy and diagnostics, but more generally may mean a combination of imaging/visualization with therapy/surgery. Specific examples will cover (1) imaging (MRI, CT and optical methods), (2) therapy (chemo, photodynamic, radiation) and (3) guided surgery (using intra-operative imaging and therapy). Progress on brain and on head and neck cancer will be reported.
Realization of silicon nanopillar arrays with controllable sidewall profiles by holography lithography and a novel single-step deep reactive ion etching
Authors: Hung Yung-Jr , Lee San-Liang , Thibeault Brian J. , Coldren Larry A. 
Published: August 2010

AbstractA simple and efficient approach for fabricating silicon nanopillar arrays with a high aspect ratio and controllable sidewall profiles has been developed by using holographic lithography and a novel single-step deep reactive ion etching. During the etching process, scalloping of the sidewalls can be avoided while reserving the high mask selectivity and high etching rate. Besides, the sidewall angle of resultant patterns can be adjusted by tuning the composition of the gas mixture of single-step DRIE process. We further fabricate a tapered silicon nanopillar array and observe its photonic bandgap property. We believe that the good optical performance of this tapered silicon nanopillar array realized by the proposed approach shows the promising of this process for various applications.
EFM Study on Ge Island: Carrier Charge and Storage Effect
Authors: Lin Zhen , Brunkov Pavel , Ma Xueying , Bassani Franck , Bremond Georges 
Published: August 2010

AbstractIn this paper, individual Ge nano island on top of a silicon dioxide layer of thermally grown on a n+ type doped silicon (001) substrate have been studied. The charging ability of an individual Ge island was evaluated by EFM two-pass lift mode measurement. Such Ge nano island becomes an iso-potential and behaves as a conductive material after being charged. These charges were directly injected and were trapped homogenous in the isolated Ge island. It is also shown that the dominant charge decay mechanism during discharging of nc-Ge is related to the leakage of these trapped charges. Further more, the retention time of these trapped charges was evaluated and the electrostatic force was also studied by using different tip bias during scan. Such a study should be very useful to the Ge-nc in memory applications.
Ultrahigh-pressure study on the magnetic state of iron hydride using an energy domain synchrotron radiation 57Fe Mössbauer spectrometer
Authors: Mitsui Takaya , Hirao Naohisa 
Published: August 2010

AbstractPressure induced magnetic phase transition of iron hydride was investigated with an in-situ Mössbauer spectrometer using synchrotron radiation (SR). The spectrometer is composed of a high resolution monochromator, an X-ray focusing device, a variable frequency nuclear monochromator and a diamond anvil cell. The optical system, advantages of the spectrometer and the observed high pressure magnetic phases of iron hydride are described.
Study of Nano-cluster Formation in Fe-18Cr ODS Ferritic Steel by Atom Probe Tomography
Authors: Kalokhtina Olena , Radiguet Bertrand , de Carlan Yann , Pareige Philippe 
Published: August 2010

AbstractA high chromium ferritic Oxide Dispersion Strengthened steel was produced by mechanical alloying of Fe-18Cr-1W-0.3Ti-0.3Ni-0.15Si and 0.5% Y2O3 (wt.%) powders in industrial attritor, followed by hot extrusion at 1100°C. The material was characterized by Atom Probe Tomography on each step of manufacturing process: as-milled powder and in final hot extruded state. In addition, to get information on clustering kinetics the powder was also characterized after annealing at 850°C during 1 hour. Atom Probe Tomography revealed that the oxide dispersion strengthened steel Fe-18Cr contains nanometer scale yttrium- and oxygen-enriched nanoclusters in as-milled state. Their evolution is shown after subsequent annealing and hot extrusion. More well defined nanophases also enriched in Ti are observed. A mechanism of their formation is proposed. Mechanical alloying results in supersaturated solid solution with presence of small Y- and O-enriched clusters. Subsequent annealing stimulates incorporation of Ti to the nucleii that were previously formed during mechanical alloying.
Probing the isothermal δ→α' martensitic transformation in Pu-Ga with in situ x-ray diffraction
Authors: Jeffries Jason R. , Blobaum Kerri J.M. , Schwartz Adam J. , Cynn Hyunchae , Yang Wenge , Evans William J. 
Published: August 2010

AbstractThe time-temperature-transformation (TTT) curve for the δ → α′ isothermal martensitic transformation in a Pu-1.9 at. % Ga alloy exhibits an anomalous double-C curve. Recent work suggests that an ambient temperature conditioning treatment enables the lower-C curve. However, the mechanisms responsible for the double-C are still not fully understood. When the δ → α′ transformation is induced by pressure, an intermediate γ′ phase is observed in some alloys. It has been suggested that transformation at upper-C temperatures may proceed via this intermediate phase, while lower-C transformation progresses directly from δ to α′. To investigate the possibility of thermally induced transformation via the intermediate γ′ phase, in situ x-ray diffraction at the Advanced Photon Source was performed. Using transmission x-ray diffraction, the δ → α′ transformation was observed as a function of time and temperature in samples as thin as 30 μm. The intermediate γ′ phase was not observed at -120°C (upper-C curve) or -155 °C (lower-C curve). Results indicate that the bulk of the α′ phase forms relatively rapidly at -120 and -155 °C.
Probing Radiation Damage in Plutonium Alloys with Multiple Measurement Techniques
Authors: McCall Scott K. , Fluss Mike , Chung Brandon W. 
Published: August 2010

AbstractA material subjected to radiation damage will usually experience changes in its physical properties. Measuring these changes in the physical properties provides a basis to study radiation damage in a material which is important for a variety of real world applications from reactor materials to semiconducting devices. When investigating radiation damage, the relative sensitivity of any given property can vary considerably based on the concentration and type of damage present as well as external parameters such as the temperature and starting material composition. By measuring multiple physical properties, these differing sensitivities can be leveraged to provide greater insight into the different aspects of radiation damage accumulation, thereby providing a broader understanding of the mechanisms involved. In this report, self-damage from α-particle decay in Pu is investigated by measuring two different properties: magnetic susceptibility and resistivity. The results suggest that while the first annealing stage obeys second order chemical kinetics, the primary mechanism is not the recombination of vacancy-interstitial close pairs.
Electronic Structure, Photoemission and Superconductivity in PuCoGa5
Authors: Shick Alexander , Khmelevskyi Sergii , Havela Ladislav 
Published: August 2010

AbstractWe study theoretically the electronic structure and photoemission spectra of PuCoGa5 making use of the LDA+Hubbard I approximation implemented in the full-potential LAPW basis, including self-consistency over the charge density. The calculations show relative reduction of the f-states spectral weight at the Fermi energy. There is fairly good agreement between calculated photoemission spectra and experimental results. We demonstrate that an account of Pu f-electron Coulomb correlations does not modify significantly the Fermi surface topologies but leads to substantial reduction of the f-character for the electronic states at the Fermi energy. These findings can be important for the theory of superconductivity in PuCoGa5 and related compounds.
Geo-descriptive Modeling of Water Conducting Features Characterized in Sedimentary Formations in Horonobe Area of Japan
Authors: Hatanaka Koichiro , Doo-hyun Lim , Ishii Eiichi 
Published: August 2010

AbstractA three-dimensional (3-D) discrete fracture network (DFN) geo-descriptive model is developed for water conducting features (WCFs) in the sedimentary formations of Horonobe underground research laboratory (URL) in Japan. Fracturing and faulting system in/around the URL area, which is the main investigation area of the Horonobe URL project, is characterized by taking into account borehole geophysical logging data, regional geologic/structural data, and fracture/fault data (orientation, intensity, size) obtained from the surface-based investigations. Volumetric fracture intensity potential is estimated by the correlation and the multi-linear regression analysis of observed data, and is used as one of controls for 3-D DFN model. A regional scale 3-D geo-descriptive DFN model is constructed based on the analyzed fracturing system identified for the WCFs. The current 3-D geo-descriptive model could be utilized explicitly to derive performance assessment (PA) parameters for the hypothetical repository of the high-level radioactive wastes in Japan, and to assist optimization of the safe repository design.