bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Fast And Efficient Simulation Tool For The Voltage Handling Capability Of High Voltage Devices
Authors: Stefanov E. , Charitat G. , Nolhier N. , Spiesser Ph. 
Published: April 2011

AbstractThe user-oriented simulator POWER2D for studying the voltage handling capability of power semiconductor devices is presented. The simulation is based on the Poisson's equation solution for an arbitrary shaped 1D, 2D, and cylindrical 3D high voltage semiconductor structures. Very fast solution of the potential is obtained for a high level of applied bias, based on incomplete LU decomposition preconditioned biconjugate gradient method, and combined with a multi-damping scheme for the Newton linearization of the non-linear algebraic equations. An original algorithm is developped ensuring a very fast and automatic search of the breakdown via the ionization integrals calculus. The predicting capability of the program is illustrated for different termination techniques showing good agreement with the experiment.
Development Of Diamond Based Power Microelectronics
Authors: Davidson J. L. , Kang W. P. , Gurbuz Y. , Kerns D. V. , Davis L. , Holmes K. , Jiang L. , Pulugurta Venkata , Anurat W. , Howell M. 
Published: April 2011

AbstractDiamond based power device structures such as resistor, capacitor, Schottky diode, p-n diode, thyristor, and field emitters are being investigated. Diamond resistors similar to standard thick film components in form and dimension were fabricated of polycrystalline diamond film. Using PECVD (plasma-enhanced chemical vapor deposition) processing to achieve diamond dielectric layers, high power, high energy density capacitors have been built. Despite grain boundaries and defects of polycrystalline diamond film, electronic devices such as field-effecttransistors and Schottky diodes have been developed. We have fabricated micro-patterned microtip arrays with this versatile new diamond technology as electron emitters. This paper will review diamond technology and results of this work.
A Study of the CdS/CuIn(Ga)Se2 Interface in Thin Film Solar Cells
Authors: Ramanathan Kannan , Wiesner Holm , Asher Sally , Niles David , Webb John , Keane James , Noufi Rommel 
Published: April 2011

AbstractIn this paper we describe our research efforts directed towards the understanding of the CdS/CuInGaSe2junctions and, specifically, the interaction of the chemical bath with the CuInGaSe2 (CIGS). We find that Cd and S diffuse into the absorber during the CdS growth. Heating the absorbers in Cd partial baths resuled in a significant improvement in the ZnO/CIGS device properties. Photoluminescence measurements indicate that the effect of Cd is very similar to that of CBD CdS.
Very high hole concentrations in C-doped InGaAs using new sources with APOMVPE
Authors: Tandon A. , Cohen R. M. 
Published: April 2011

AbstractNew sources have been used to grow the first carbon doped, highly p-type InxGa1-xAs (0.2>x>0.7) epilayers on InP substrates by atmospheric pressure organometallic vapor phase epitaxy (APOMVPE). Excellent morphology was obtained simultaneously with high hole concentrations at growth temperatures near 450 °C. High hole concentrations of 1.6×1019 – 8.7×1019 cm−3 (the highest reported to date for APOMVPE), and the corresponding room temperature hole mobilities of 65 – 25 cm2/s, respectively, have been obtained from Hall measurements. X-ray diffraction is consistent with excellent crystal quality. Annealing at temperatures of T=400–500 °C in the presence of either nitrogen or hydrogen was found to change the carrier concentration by only 0–15%. However, after annealing at T=650 °C, irreversible changes occurred in the InGaAs. After a high temperature anneal, reversible order of magnitude changes in the hole concentration was obtained upon further annealing at low temperatures, depending upon the ambient. These results conclusively show that hydrogen does not passivate C acceptor ions in InGaAs. Since changes in the carrier concentration become substantial and reversible only after high temperature annealing, the results strongly suggest that a structural change occurred in the crystal at high temperatures. We consider it likely that this structural change is the precipitation of carbon out of a supersaturated solid solution, and that hydrogen atoms associated with these precipitates act as donors which compensate the hole concentration.
Optical Characterization of Ultrathin Silicon Substrates
Authors: Globus T. , Jones S. H. , Digges T. 
Published: April 2011

AbstractIn this paper we present results for the absorption coefficient and refractive index spectra of p-and n-type silicon membranes doped with phosphorous or boron at different levels. These results cover the wide energy range from 0.5 eV up to 2.5 eV, thus including effects of subgap defect and impurity absorption, and the range of possible transitions to higher conduction band minima. The results have been obtained by utilizing both a conventional transmission and reflection measurement technique at small values of transmittance, and a recently developed optical interference spectroscopy characterization technique. The results in the visible and near infrared regions from the two techniques have been compared, and the range of transmission where the conventional technique is applicable have been determined. The preliminary analysis of these data indicate that a new information regarding the Si electronic band structure can be extracted.
Plasma Deposition and Interface Control in Low Temperature Processing of Thin Film Solar Cells
Authors: Jagannathan B. , Anderson W. A. 
Published: April 2011

AbstractPlasma deposition of thin silicon films with a variable microstructure and controlled interface formation techniques are being developed for thin film silicon/polycrystalline silicon solar cells. Low hydrogen content amorphous (a-Si) or microcrystalline silicon (μ c-Si) films were obtained by controlling the H2 dilution of 2% SiH4/He in a microwave ECR discharge. The films were characterized for structural and electro-optic properties. Junction creation for solar cells was investigated by depositing single or multilayers of the film silicon onto crystalline silicon (c-Si). Effort to improve carrier transport and photovoltaic (PV) properties was pursued through interface modifications effected by varying the microstructure of the layer in contact with the substrate. Cells with 7% conversion efficiency (No A/R) were obtained for an a-Si/c-Si heterojunction configuration. Improved carrier transport and PV properties (9% ef ficient) were achieved by inserting a thin μ c-Si layer in the above structure.
Nanocrystalline Silicon/Amorphous Silicon Dioxide Superlattices
Authors: Fauchet Philippe M. , Tsybeskov Leonid , Zacharias Margit , Hirschman Karl 
Published: April 2011

AbstractThin layers made of densely packed silicon nanocrystals sandwiched between amorphous silicon dioxide layers have been manufactured and characterized. An amorphous silicon/amorphous silicon dioxide superlattice is first grown by CVD or RF sputtering. The a-Si layers are recrystallized in a two-step procedure (nucleation + growth) to form layers of nearly identical nanocrystals whose diameter is given by the initial a-Si layer thickness. The recrystallization is monitored using a variety of techniques, including TEM, X-Ray, Raman, and luminescence spectroscopies. When the a-Si layer thickness decreases (from 25 nm to 2.5 nm) or the a-SiO2 layer thickness increases (from 1.5 nm to 6 nm), the recrystallization temperature increases dramatically compared to that of a single a-Si film. The removal of the a-Si tissue present between the nanocrystals, the passivation of the nanocrystals, and their doping are discussed.
Si Surface Preparation with Si Beam Irradiation on the Growth of III-V on Si
Authors: Kawanami H. , Baskar K. , Sakata I. , Sekigawa T. 
Published: April 2011

AbstractThe preliminary results of the effects of the Si beam irradiation for the Si surface preparation on the growth of GaAs on Si by MBE are reported. The effects are combined with thermal cyclic anneal (TCA). A slight improvement in the crystalline quality is observed on the photoluminescence spectra of the films grown with Si irradiation. In our experimental conditions, Si irradiation during the Si surface preparation has not indicated large effects on the FWHM of XRD. It is also indicated that initial substrate surface treatment affects the quality of thicker film through TCA treatment. Higher substrate temperature during Si beam irradiation is expected to indicate positive Si beam irradiation effects.
Electroluminescent Devices Based On Polycrystalline Silicon Films For Large-Area Applications
Authors: Koshida N. , Takizawa E. , Mizuno H. , Arai S. , Koyama H. , Sameshima T. 
Published: April 2011

AbstractIt is shown that porous polycrystalline Si (PPS) diodes operate as light-emitting diodes (LEDs) with efficiencies comparable to conventional porous silicon (PS) diodes fabricated on singlecrystalline substrates. Judging from the electroluminescence (EL) characteristics such as emission spectra, diode current dependence of EL intensity, and its temperature dependence, the common EL mechanism seems to exist in PPS and PS diodes. Observed similarity in the photoluminescence (PL) properties between PPS and PS is consistent with this hypothesis. The capability of a poly-Si thin film transistor as a driver of PPS-LED is also demonstrated.
A Led Based on Porous Polycrystalline Silicon
Authors: Huang W. N. , Tong K. Y. , Chan P. W. 
Published: April 2011

AbstractPrevious studies on electroluminescence in porous silicon were based on crystalline wafers. In this paper, we shall report the characteristics of a LED based on porous effects in a cast polycrystalline silicon substrate. A layer of porous region was first formed on a cast polycrystalline silicon substrate by anodization, followed by the deposition of a semitransparent Au layer. Under forward bias, the LED emits stable yellowish white light (with the presence of bright spots) for currents above 20 mA/cm2. From the electroluminescence spectra measured, we suggest that the emission is due to the recombination of electron-hole pairs in a microplasma region. We propose a model where the microplasma is present in the depletion region of the heterojunction formed between the bulk polysilicon and the surface porous polysilicon. The defects and grain boundaries in a polycrystalline material facilitate the formation of such microplasma. The heterojunction model will also be used to explain the current characteristics of the LED. The effect on the LED characteristics due to indium coating on the porous substrate prior to Au deposition was studied, and the results agree with the heterojunction model. Our work shows that cast polycrystalline silicon substrates have potential for LED fabrication in cheap and large area applications.
Electroluminescence study of Si-Si1-xGex/Si1-yCy-Si p-i-n diode structures
Authors: B. Joelsson Kenneth , Ni Wei-Xin , Du Chun-Xia , V. Hansson Göran 
Published: April 2011

AbstractThe electroluminescence from p-i-n diode structures with Si1-yCy/Si1-xGex layers in the depletion region has been studied. Emission attributed to an overlap of the wavefunction associated with electrons confined in the Si1-yCy layer and the wavefunction associated with holes confined in the Si1-xGe, layer has been observed. For low injection currents, emission due to recombination occurring in the Si1-xGex layer is more dominant. For structures with higher C concentration, the interface related emission can persist up to higher temperatures.
Lattice Sites and Stability of Implanted Er in FZ and CZ Si
Authors: Wahl U. , Correia J. G. , Langouche G. , Vantomme A. , collaboration Isolde 
Published: April 2011

AbstractWe report on the lattice location of 167Er in Si measured by conversion electron emission channeling. In both FZ and CZ Si, a high fraction of Er (>65%) occupies near-tetrahedral interstitial (T) sites directly following 60 keV room temperature implantation at doses of 6× 1012 cm−2 For higher doses, the as-implanted near-T fractions of Er visible by emission channeling are smaller, due to the beginning of amorphization. Following the recovery of implantation damage at 600°C, more than 70% of Er is found on near-T sites in both FZ and CZ Si. In FZ Si, Er exhibits a remarkable thermal stability and only prolonged annealing for several hours reduces the near-T fraction. On the other hand, annealing of CZ Si at 900°C for more than 10 minutes results in the majority of Er probes in sites of very low symmetry or disordered surroundings.
Photoluminescent Silicon in Nanoporous Aluminium Oxide
Authors: Heilmann Andreas , Jutzi Peter , Klipp Andreas , Kreibig Uwe , Neuendorf Rolf , Sawitowski Thomas , Schmid Günter 
Published: April 2011

AbstractThermal decomposition of a metastable silane in nanoporous alumina leads to the formation of luminescent silicon nanostructures. While varying the pore size of the transparent membranes the luminescence can be shifted from 504 nm up to 537 nm by building up a sheet-like structure of siloxene on the inner pore surface.
Electronic Structures of Halogenated Polysilanes
Authors: Motoyama Hideshi , Takeda Kyozaburo , Shiraishi Kenji 
Published: April 2011

AbstractThe electronic structures of halogenated polysilanes (PSi), whose side chains are replaced by halogen (X) atoms, have been theoretically investigated based on the firstprinciples calculations. It was found that non-bonding (n) electrons localizing at the X atom produce an important orbital mixing with the u valence electrons delocalized in the direction of the PSi skeleton (a-n mixing). This a-n mixing splits the top of the valence bands, and creates unoccupied states in the band gap. This valence-band-splitting effectively narrows the band gap to the visible range, and the unoccupied state in the band gap has the potential to be an electron acceptor. Moreover, we also investigated several replacement patterns as well as the kind of replaced halogen species (X=F, Cl, Br, I). The dispersion and energy position of the unoccupied state(s) can be artificially tuned by these chemical modifications. Thus, halogenation can change PSi into optelectronic polymers with visible photoluminescence.
Active Silicon Integrated Optical Circuits
Authors: Bestwick Tim D. 
Published: April 2011

AbstractActive Silicon integrated Optical Circuits (ASOC™) is a technology based on single-mode rib waveguides formed on silicon-on-insulator that is being used to manufacture commercial integrated optics components. Silicon waveguides have excellent properties for many applications in the 1.3 and 1.55 micron telecommunications bands including relatively low loss. An important aspect of ASOC™ technology is the development of a set of waveguide-based elements that can be assembled into practical integrated optics devices. The fundamental waveguide elements include bends, couplers and fiber-waveguide interfaces, and additional elements include doped structures and waveguide gratings. Discrete lasers and photodetectors are also incorporated into ASOC™ technology to form hybrid devices. The technology is being used to manufacture devices for applications in telecomunications and optical sensing, the first major product being a two-wavelength single-fiber bi-directional optical transceiver.
Generating an Intracellular Diffusion Map by Two-Photon Fluorescence Correlation Spectroscopy
Authors: So P. T. C. , Duggar K. , Berland K. M. , Gratton E. 
Published: April 2011

AbstractA new technique for determining cellular viscosity has been developed based on two-photon excitation and fluorescence correlation spectroscopy. We have applied this method to map intracellular diffusion coefficient of small molecules at selected cytoplasmic locations of mouse fibroblast cells. The cytoplasmic diffusion rate is one tenth of that in an aqueous environment.
Structure and Forces in Transfection Related Surfactant Systems
Authors: Campbell Samuel E. , Park Chad K. , Lasic Dan D. , Israelachvili Jacob N. 
Published: April 2011

AbstractExperiments have been performed on the cationic bilayer and liposome-forming surfactant DODAB, a successful DNA transfection agent. The surface forces apparatus (SFA) was utilized to measure the long-range colloidal and short-range adhesion forces between Langmuir-Blodgett bilayers exposing DODAB in the outer monolayers. Forces were measured in aqueous solutions of varying salt concentrations between 1 and 10 mM, with and without single-stranded DNA added to the solution. These represent the first measurements of the forces between surfactant/DNA assemblies. At low salt concentrations without DNA, the interbilayer forces are repulsive due to their electrostatic interaction, in agreement with DLVO theory. In contrast, in the presence of DNA which adsorbs to the bilayer surfaces, the forces between the bilayers changed to an enhanced and longer ranged repulsive steric-electrostatic interaction. At shorter range. the DNA can be excluded from the gap leading to an enhanced adhesion at contact accompanied by lipid rearrangement.
On Motion of Adhering Vesicles
Authors: Durand I. , Misbah C. 
Published: April 2011

AbstractWe study theoretically phospholipid vesicle locomotion caused by adhesion. The problem is solved numerically, and an analytical solution is obtained in a perturbative scheme. The analytical result reproduces the numerical one. We provide an expression for the drift velocity as a function of relevant parameters when only local dissipation is present. We briefly discuss the transition from sliding to rolling when hydrodynamics are included. We mention situations where the vesicle may itself establish an adhesion gradient. We propose some simple experimental protocols.
Reptation of Microtubules in F-Actin Networks : Effects of Filament Stiffness and Network Topology on Reptation Dynamics
Authors: Shah Jagesh V. , Flanagan Lisa A. , Bahk David , Janmey Paul A. 
Published: April 2011

AbstractThe thermally driven motions of fluorescently labeled microtubules embedded in a network of filamentous actin polymers are analysed as the diffusion of a rod-like polymer within a virtual tube formed by the surrounding semiflexible actin filaments. The apparent diffusion constant parallel to the tube scales with the inverse of the microtubule length and the magnitude is consistant with diffusion through a medium with a viscosity of approximately 10 centipoise. Introduction of crosslinks between the actin filaments does not alter the diffusion of the microtubules in the actin network.
Quantal Motor Action in Muscle Contraction
Authors: Pollack G. H. , Blyakhman F. , Shklyar T. , Tourovskaia A. , Tameyasu T. , Yang P. 
Published: April 2011

AbstractIt is becoming clear that quantal behavior is a central feature of contractile systems. Steplike behavior has been demonstrated in the kinesin - microtubule system and in the myosin - actin filament system-both on molecular scale. We show here that step-like features appear also in the single intact sarcomere. We studied single sarcomeres of single bumblebee myofibrils. Motorimposed ramp length changes on activated myofibrils resulted in sarcomere-length changes that were stepwise. Computer analysis of the stepwise shortening patterns revealed a step-size distribution containing multiple peaks. The peaks were separated by 2.7 nm per half-sarcomere which is the linear actin-subunit spacing. Thus, translation steps are an integer multiple of the actin-subunit spacing. This result parallels the one observed in the kinesin-tubulin spacing where step size is a multiple of the tubulin-subunit spacing. In the muscle system, however, the steps are preserved on a macroscopic scale, implying high synchrony. The quantal steps are easily explained by a model in which the actin filament propels itself over stationary cross-bridges: if actin binds to the cross-bridges between steps, then the observed quantal result is inevitable.
Fermi-Level Effect on Group III Atom Interdiffusion in III-V Compounds: Bandgap Heterogeneity and Low Silicon-Doping
Authors: Chen C.-H. , Gösele U. , Tan T. Y. 
Published: April 2011

ABSTRACTHeavy n-doping enhanced disordering of GaAs based III-V semiconductor superlattice or quantum well layers, as well as the diffusion of Si in GaAs have been previously explained by the Fermi-level effect model with the triply-negatively-charged group III lattice vacancies identified to be the responsible point defect species. These vacancies have a thermal equilibrium concentration proportional to the cubic power of the electron concentration n, leading to the same dependence of the layer disordering rate. In this paper, in addition, we take into account also the electric field effect produced by the material bandgap heterogeneity and/or hetero-junctions. In heavily n-doped or long time annealing cases, this effect is negligible. At low n-doping levels and for short annealing times, the layer disordering rate can be enhanced or reduced by this effect. Available experimental results of low Si-doped and very short-time annealed samples have been satisfactorily fitted using the Fermi-level effect model.
Defect Reactions Induced by Reactive Ion Etching
Authors: Zhao Song , Kimerling Lionel C. 
Published: April 2011

ABSTRACTReactive ion etching (RIE) causes substrate surface contamination, substrate damage, and induces defect reactions to produce carrier traps at depths into μm range. We have developed a model describing the indiffusion of interstitials and the subsequent reactions in the defect reaction region to predict the defect depth profiles. We formulate the reaction kinetics as a series of 1-D coupled interstitial diffusion-reaction partial differential equations (PDEs) with a moving boundary. The predicted defect depth profiles are consistent with those measured in the photoluminescence (PL) experiments. We conclude that the defect depth profiles are determined by interstitial diffusion coefficient (Di), etch rate (υE), etch time (tE), defect reaction rate (K), and background dopant and impurity concentrations ([C], [B] and [O]) in the Si substrate. The μm range defect depth profiles can be explained as: (i) fast diffuser Si self-interstitial (Sii) indiffusion to a μm depth range of (Di/K)1/2 limited by [C] and [B]; (ii) the generation of carbon and boron interstitials (Ci and Bi) through the Watkins replacement reactions, and (iii) the formation of Ci- and Bi-related defect pairs through diffusion limited pairing reactions. Ci and Bi indiffusion are limited by υE and extremely shallow (Di/υE) during a typical RIE process with υE≈1000Å/min and tE≈10min. The indiffusion of vacancies (V), contamination from the etching plasma and enhanced diffusion effects are also considered in the model.
Chemical Kinetics Models for Semiconductor Processing
Authors: Coltrin Michael E. , Meeks Ellen , Grcar Joseph F. , Houf William G. , Kee Robert J. , Randall Creighton J. 
Published: April 2011

ABSTRACTChemical reactions in the gas-phase and on surfaces are important in the deposition and etching of materials for microelectronic applications. A general software framework for describing homogeneous and heterogeneous reaction kinetics utilizing the Chemkin suite of codes is presented. Experimental, theoretical and modeling approaches to developing chemical reaction mechanisms are discussed. A number of TCAD application modules for simulating the chemically reacting flow in deposition and etching reactors have been developed and are also described.