bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of Buried CoSi2 Layers in Si(100) by Molecular Beam Allotaxy
Authors: Mantl S. , Bay H.L. , Michel I. , Mesters S. , Trinkaus H. 
Published: September 2012

ABSTRACTBuried single crystalline CoSi2 layers in Si(100) have been grown using molecular beam allotaxy. In this paper, we investigated the diffusive interaction of two buried silicide precipitate layers, one with a small Co peak concentration of 10 at% and another one with 26 at%. Annealing causes first local coarsening in each layer, and then dissolution of the thinner precipitate layer. The accumulation of the Co atoms at the thicker layer is described by a simple model for the diffusional redistribution.
Fractals in Porous Media: From Pore to Field Scale
Authors: Sahimi Muhammad , Rassamdana Hossein , Mehrabi Alireza 
Published: September 2012

AbstractTwo applications of fractal concepts to problems involving porous media are discussed. One of them occurs at the pore level and involves the formation of large molecular aggregates as the result of injecting a fluid into an oil reservoir, or because of compositional changes in the oil. Formation of such aggregates and their precipitation on the pore surfaces cause severe problems for enhanced recovery of oil, and also many processes which use porous catalysts. We argue that these molecular structures are similar to diffusion-limited cluster-cluster aggregates, and small-angle neutron scattering data support our argument. The second application involves field-scale distributions of the porosity and permeability of oil reservoirs. We show that, contrary to the recent assertions that such distributions are described by fractional Brownian motion or fractional Gaussian noise with positive correlations (persistence), they are described by Lévy distributions withnegativecorrelations (anti-persistence).
Two-Length-Scale Structure in Some Computer-Generated Aggregates Grown by Diffusion-Limited Aggregation
Authors: Schmidt Paul W. , Pipitone Giuseppe , Floriano M. A. , Caponetri E. , Triolo R. 
Published: September 2012

AbstractThe properties of some aggregates “grown” on a computer by diffusion-limited aggregation have been investigated. Calculations showed that the intensity of the small-angle x-ray and neutron scattering from the aggregates was proportional to q−D for qL ≫ 1, where D > 0, L is a length that characterizes the large-scale structure of the aggregate, q = 4πλ−1 sin(θ/2), γ is the wavelength, and θ is the scattering angle. The magnitude of the exponent D was appreciably smaller than the fractal dimensions that many simulations have shown to be typical of the mass fractal aggregates grown by diffusion-limited aggregation. The calculations suggest that the aggregates have structure on two different characteristic-length scales.
A Theory for Growing Interfaces in Laplacian Fields: A Many-Body Formulation and Statistical Analysis
Authors: Blumenfeld Raphael 
Published: September 2012

AbstractI formulate a theory for the growth of an interface in a Laplacian field. The problem is mapped to a many-body system and the process is shown to be Hamiltonian. The corresponding set of dynamical equations is analysed and surface effects are introduced as a term in the Hamiltonian that gives rise to a repulsion between the quasi-particles and the interface. The theory accommodates anisotropic surface effects. The underlying Hamiltonian allows a statistical-mechanical analysis of the limit distribution of the quasi-particles. Noise can be naturally incorporated in this formalism. Finally the distribution of the particles is translated into the statistics of the interface, which leads to predictions on the morphology. The main thrust of this approach is in finding a statistical mechanical approach to this nonequilibrium process.
From Facets to Fractals - Growth Morphologies in Molecular Crystals of Carbon Tetrabromide (Cbr4) and Fullerene C60
Authors: Xiao Rong-Fu 
Published: September 2012

AbstractWe have experimentally studied the growth morphologies of carbon tetrabromide CBr4 and fullerene C60crystals in their orientationally disordered solid phases. Very rich growth morphologies have been observed from these crystals, ranging from facets to dendrites and to fractals. In the vapor growth of CBr4crystals, we found that the growth morphologies depend not only on temperature and supersaturation, but also sensitively on the total pressure of the inert gas in the growth chamber. With increasing total pressure, under otherwise the same growth conditions, crystals with initially smooth surfaces evolve into dendritic structures. For fullerene C60, the growth morphologies from solution are mainly fractals with strong anisotropy in the individual crystals. The growth morphologies from vapor are normally faceted and the growth proceeds via a layer-by-layer mode.
Reail Space Renormalization Group for Self Organized Criticality in Sandpile Models
Authors: Zapperi S. , Vespignanit A. , Pietronero L. 
Published: September 2012

AbstractWe have introduced a new renormalization group approach that allows us to describe the critical stationary state of sandpile models (Phys. Rev. Lett. 72, 1690 (1994)). We define a characterization of the phase space in order to study the evolution of the dynamics under a change of scale. We obtain a non trivial actractive fixed point for the parameters of the model that clarifys the self organized critical nature of these models. We are able to compute the values of the critical exponents and the results are in good agreement with computer simulations. The method can be naturally extended to several other problems with non equilibrium stationary state.
Ion Beam Modification of Cluster-Covered Silicon Surfaces
Authors: Gulko O. V. , Zinke-Allmang M. T. 
Published: September 2012

AbstractClusters of independently tailored areal density and size distribution were grown on semiconductor surfaces in ultra-high vacuum and used as masks for selective ion beam modification. First studies were undertaken to characterize the vertical interface between areas exposed to low energy ion beams and areas covered by clusters (crystalline silicon). Selective etching was employed to create a patterned surface as a substrate for heteroepitaxial growth of thick Ge layers to test defect density reduction due to finite size growth areas. The quality of the overlayers is discussed.
Formation and Characteristics of CoSi2 Layers Synthesized by Mevva Implantation
Authors: Wong S. P. , Peng Qicai , Cheung W. Y. , Guo W. S. , Xu J. B. , Wilson I. H. , Hark S. K. , Morton R. , Lau S. S. 
Published: September 2012

AbstractIon beam synthesis of CoSi2 layers in Si by MEVVA (Metal Vapor Vacuum Arc) implantation has been performed under various conditions. The formation and characteristics of these CoSi2 layers have been studied by XTEM, RBS, AFM, X-ray diffraction, ellipsometry, electrical and Hall effect measurements. It was found that a higher substrate temperature during implantation results in an as-implanted Co distribution closer to the surface and hence the formation of a shallower CoSi2 layer after annealing. Buried CoSi2 layers of good crystal quality and low resistivity CoSi2 can be formed by MEVVA implantation and annealing under appropriate conditions. A strong temperature dependence of the Hall coefficient showing a large peak at around 100K was observed for the CoSi2 layers formed in p-type Si substrates but not in n-type substrates. The properties and their dependence on the processing conditions, in particular, the substrate temperature during implantation, are presented and discussed.
Plasma Doping and Plasma-Less Doping of Semiconductor
Authors: Mizuno Bunji , Takase Michihiko , Nakayama Ichiro , Ogura Mototsugu 
Published: September 2012

AbstractNew doping processes which can alternate the ion implantation to achieve the ultra shallow junction are reviewed. Mainly two ways have been proposed. One uses plasma and the other uses vapor phase reaction. 0.17μm Surface Channel (SC) - PMOSFET's have been successfully fabricated by especially plasma doping method.
Range and Damage Distribution in Cluster Ion Implantation
Authors: Yamada I. , Matsuo J. , Jones E. C. , Takeuchi D. , Aoki T. , Goto K. , Sugii T. 
Published: September 2012

AbstractCluster ion implantation is an attractive alternative to conventional ion implantation, particularly for shallow junction formation. It is easy to obtain high-current ion beams with low equivalent energy using cluster ion beams. The implanted boron distribution in 5keV B10H14 implanted Si is markedly shallower than that in 5keV BF2 ion implanted Si. The implanted depth is less than 0.04 μm, indicating that cluster ion implantation is capable of forming shallow junctions. The sheet resistance of 3keV B10H14 implanted samples falls below 500 Ω/sq after annealing at 1000°C for 10s. Shallow implantation can be realized by a high energy cluster beam without space-charge problems in the incident beam. Defect formation, resulting from local energy deposition and multiple collisions, is unique for cluster ions. The thickness of the damaged layer formed by cluster ion bombardment increases with the size of the cluster, if implant energy and ion dose remain constant. This is one of the nonlinear “cluster effects,” which may allow some control over the implant damage distributions that accompany implanted ions, and which have been shown to have a great effect on dopant redistribution during annealing
Electrical Resistivity of Copper Films by Partially Ionized Beam Deposition
Authors: Han S. , Yoon K. H. , Kim K. H. , Jang H. G. , Choi S. C. , Jung H. J. , Koh S. K. 
Published: September 2012

AbstractCopper films on Si(100) were prepared by partially ionized beam at 0 kV and 3 kV acceleration voltages in order to investigate effects of ion energy on electrical property with thickness. X-ray diffraction(XRD) pattern analysis was used to investigate crystallinity of the copper films, microstructure by Scanning electron microscope(SEM) and surface roughness by atomic force microscopy(AFM). The crystallinity of the copper films grown at the 3 kV was more (111) textured than that at the 0 kW. The copper films grown at the both condiitions had nearly same grain size below a thickness of 1000 Å. The 1800 Å Cu film grown at the 3 kV was 3 times rough than that at the 0 kV. The resistivity of copper films increased due to surface and grain boundary scattering, and the change of resistivity was discussed in terms of surface roughness, grain size and film density assisted by average depositing energy.
Charge State Defect Engineering of Silicon During Ion Implantation
Authors: Brown R. A. , Ravi J. , Erokhin Y. , Rozgonyi G. A. , White C. W. 
Published: September 2012

AbstractThe effects of in situ interventions which alter defect interactions during implantation, and thereby affect the final damage state, have been investigated. Specifically, we examined the effects of internal electric fields and charge carrier injection on damage accumulation in silicon. In the first part of this work, we implanted H or He ions into diode structures which were either reverse or forward biased during implantation. In the second part, we implanted B or Si ions into plain silicon wafers whilst illuminating them with UV light. In each case, the overall effect is one of damage reduction. Both the electric field and charge carrier injection effects may be understood as resulting from changes in defect interactions caused in part by changes to the charge state of defects formed during implantation.
Modeling of Extended Defects in Silicon
Authors: Law M. E. , Jones K. S. , Earles S. K. , Lilak A. D. , Xu J-W. 
Published: September 2012

AbstractTransient Enhanced Diffusion (TED) is one of the biggest modeling challenges present in predicting scaled technologies. Damage from implantation of dopant ions changes the diffusivities of the dopants and precipitates to form complex extended defects. Developing a quantitative model for the extended defect behavior during short time, low temperature anneals is a key to explaining TED. This paper reviews some of the modeling developments over the last several years, and discusses some of the challenges that remain to be addressed. Two examples of models compared to experimental work are presented and discussed.
He Implanted Channel Waveguides of New Design for Efficient Blue Laser Light Generation
Authors: Beckers L. , Bauer St. , Buchal Ch. , Fluck D. , Pliska T. , Günter P. 
Published: September 2012

AbstractWe present a new mask design and implantation scheme, which uses one single ion implantation step of 2 MeV He ions at a dose of 7–1014 to 3–1015 He/cm2 to form channel waveguides in single crystalline KNbO3. The special processing of the photoresist mask enables the formation of channel waveguides with a trapezoidal-shaped cross section, providing for the first time simultaneous confinement of both TE and TM modes in a permanent KNbO3 channel waveguide. 2.6 mW second-harmonic blue light at 441 nm was generated in a 5.8 mm long guide for a fundamental power of approx. 200 mW.
Identification of Hydrophilic Group Formation on Polymer Surface During Ar+ Ion Irradiation in O2 Environment
Authors: Cho Jun-Sik , Choi Won-Kook , Kim Sung-Ryong , Jung Hyung-Jin , Koh Seok-Keun 
Published: September 2012

AbstractAr+ ion irradiation on low density polyethylene (LDPE), and polystyrene (PS) was performed in an O2 environment in order to improve wettability of polymers to water and to identify the formation of hydrophilic groups originated from chemical reactions on the surface of polymers. Doses of a broad Ar+ ion beam of 1 keV energy were changed from 5 × 1015 to 1 × 1017 /cm2 and the rate of the oxygen gas flowing near the sample surface was varied from 0 to 7 mi/min. The contact angle of polymers was not reduced much by Ar+ ion irradiation without oxygen gas. However, it dropped largely to a minimum of 35 ° and 26 ° for At+ ion irradiation in the presence of flowing oxygen gas on LDPE and PS, respectively. From x-ray photoelectron spectroscopy analysis, it was observed that hydrophilic groups were formed on the surface of polymers through an ion-assisted chemical reaction between the ion-induced unstable chains and oxygen. The newly formed hydrophilic group was identified as -(C=O)- bond and -(C=O)-O- bond. The contact angle of polymer was greatly dependent on the hydrophilic group formed on the surface.
Plasma and Ion Beam Tools for Enhanced Battery Electrode Performance
Authors: Anders A. , Kong F. , Chen Y. , Monteiro O. R. , McLarnon F. R. , Brown I. G. 
Published: September 2012

AbstractPlasma and ion beam methods such as gas and metal ion implantation, plasma immersion ion implantation (PIII), and metal plasma immersion ion implantation and deposition (MePIIID) are introduced as powerful tools to modify the properties of battery electrodes. Three kinds of rechargeable electrochemical cells have been investigated: the lead-acid cell, the nickel alkaline-electrolyte cell, and the lithium cell. It was experimentally shown that (i) metal ion implantation of Ti, V, Cr, Ni, and W into lead and lead-antimony electrodes reduced the corrosion current by more than one order of magnitude, (ii) cobalt ion implantation into nickel electrodes enhanced the interconversion of Ni(OH)2 to NiOOH and the associated cycle life, (iii) nitrogen-PIII resulted in the formation of a nitrided lithium layer on lithium which stabilized the surface against corrosion, (iv) MePIIID with a tungsten plasma reduced the pitting corrosion of aluminum, a current collector for a lithium battery.
Carbon Nitride Films Formed using Sputtering and Negative Carbon Ion Sources
Authors: Murzin I. H. , Tompa G. S. , Wei J. , Muratov V. , Fischer T. E. , Yakovlev V. 
Published: September 2012

AbstractWe report the results of using sputtering and negative carbon ion sources to prepare thin films of carbon nitride. In this work, we compare the structural, tribological, and optical properties of the carbon nitride films that were prepared by two different ion assisted techniques. In the first approach we used a magnetron gun to sputter deposit carbon in a nitrogen atmosphere. The second method utilized a beam of negatively charged carbon ions of 1 to 5 μA/cm2 current density impinging the substrate simultaneously with a positive nitrogen ion beam produced by a Kaufman source. We were able to synthesize microscopically smooth coatings with the carbon to nitrogen ratio of 1 : 0.47. These films possess wear rates lower than 5×10−7 mm3/Nm and friction coefficients in the range of 0.16 to 0.6. Raman spectroscopy revealed that the magnetron sputtered films are more structurally disordered than those formed with the negative carbon ion gun. FTIR showed the presence of the C≡N stretching mode in both types of films. Finally, spectroscopic ellipsometry produced films with dielectric constants as low as 2.3 in the photon energy range from 1.2 to 5 eV.
Dose Rate Effects During Damage Accumulation in Silicon
Authors: Caturla M.-J. , Rubia T. Diaz de la 
Published: September 2012

AbstractWe combine molecular dynamics and Monte Carlo simulations to study damage accumulation and dose rate effects during irradiation of Silicon. We obtain the initial stage of the damage produced by heavy and light ions using classical molecular dynamics simulations. While heavy ions like As or Pt induce amorphization by single ion impact, light ions like B only produce point defects or small clusters of defects. The amorphous pockets generated by heavy ions are stable below room temperature and recrystallize at temperatures below the threshold for recrystallization of a planar amorphous-crystalline interface. The damage accumulation during light ion irradiation is simulated using a Monte Carlo model for defect diffusion. In this approach, we study the damage in the lattice as a function of dose and dose rate. A strong reduction in the total number of defects left in the lattice is observed for lower dose rates.
HRLEED and STM Study of Misoriented Si (100) with and without a Te Overlayer
Authors: Yala Salima , Montano Pedro A. 
Published: September 2012

AbstractThe growth of high quality Te on misoriented Si(100) is important as an intermediate phase for epitaxial growth of CdTe. The misorientation angle plays a key role in the growth quality of CdTe/Si(100); this incited our curiosity to investigate the effect of the misorientation angle on the topography of the surface structure of Si(100). Our main goal is to show the relation between the misorientation angle, the terrace width and the step height distributions. HRLEED ( High Resolution Low Energy Electron Diffraction ) provides information in reciprocal space while STM gives real space topographic images of the surface structure. STM and HRLEED measurements were performed on Si(100) with misorientation angle υ= 0.5°, 1.5° and 8° towards the ]110] direction and υ= 4° towards the ]130] direction. Except for the 8° misorientation in which case a regular step array with diatomic step height was observed, for the other misorientations the terrace width was variable. The average terrace width decreased with increasing misorientation angle. A mixture of diatomic and monatomic step heights was observed on the 0.5° and 1.5° misoriented Si(100) samples. It proves that one can not assume purely monatomic step height for low misorientation angles. Our results do not agree with the belief that at low miscut angle A and B terraces are equal and that as the misorientation angle increases the B terrace tends to be wider than the A terrace. In fact, pairing of terraces was not observed at all. Te was deposited at a substrate temperature of 200 C. We observed a significant reduction in the terrace widths for all miscut angles.
Microstructural Studies of Co Silicide Layers Formed on SiGe and SiGeC
Authors: Jin S. , Bender H. , Donaton R.A. , Maex K. , Vantomme A. , Langouche G. , Amour A.St. , Sturm J.C. 
Published: September 2012

AbstractTransmission electron microscopy is used to investigate the structural development as a function of the annealing temperature of Co-silicides prepared on SiGe and SiGeC. The transition temperature from Co(SiGe) into Co(SiGe)2 is higher for SiGeC than for SiGe.
Monitoring of Dopant Activation in Sub-Surface P-Type Si Using the Surface Charge Profiling (SCP) Method
Authors: Roman P. , Staffa J. , Fakhouri S. , Ruzyllo J. , Kamieniecki E. 
Published: September 2012

AbstractIn this study the SCP (Surface Charge Profiling) method, based on non-contact, small-signal ac-SPV measurement is used to study thermal activation of boron in the near surface region of p-type Si wafers. Boron tends to form pairs with impurities such as hydrogen, iron and copper in the near surface region of Si substrates which render it inactive. During device processing, activation of boron may take place resulting in uncontrolled variations in active boron concentration in the near surface region.In this work, both boron doped, polished CZ wafers and wafers with boron doped epitaxial layers are studied. In the former case, the concentration of active boron in the near surface region was initially up to an order of magnitude less than the bulk concentration determined from four-probe measurements, but increased with the temperature of an anneal in ambient air and approached the bulk value. In contrast, the wafers with epitaxial layers showed no consistent variations of surface dopant concentration with temperature. These results confirmed previous findings that the near surface region of the polished wafers is contaminated with metals introduced during polishing operations. The SCP method was found to be very effective in monitoring variations in active boron concentration in the near-surface region.
Box Model of Radionuclide Dispersion and Radiation Risk
Estimation for Population in Case of Radioactivity Release from Nuclear
Submarine #601 Dumped in the Kara Sea
Authors: Yefimov E. I. , Pankratov D. V. , Ignatiev S. V. 
Published: September 2012

ABSTRACTA relatively simple model is suggested for radionuclide dispersion and
assessment of additional population dose and radiation risk for radionuclide
release from the nuclear submanne (NS) #601 with Pb-Bi coolant that was
dumped in the Kara Sea.
Glass-Ceramic Waste Forms for Immobilizing
Plutonium
Authors: O'Holleran T. P. , Johnson S. G. , Frank S. M. , Meyer M. K. , Noy M. , Wood E. L. , Knecht D. A. , Vinjamuri K. , Staples B. A. 
Published: September 2012

ABSTRACTResults are reported on several new glass and glass-ceramic waste
formulations for plutonium disposition. The approach proposed involves
employing existing calcined high level waste (HLW) present at the Idaho
Chemical Processing Plant (ICPP) as an additive to: 1) aid in the formation
of a durable waste form and 2) decrease the attractiveness level of the
plutonium from a proliferation viewpoint. The plutonium, PuO2,
loadings employed were 15 wt% (glass) and 17 wt% (glass-ceramic). Results in
the form of x-ray diffraction patterns, microstructure and durability tests
are presented on cerium surrogate and plutonium loaded waste forms using
simulated calcined HLW and demonstrate that durable phases, zirconia and
zirconolite, contain essentially all the plutonium.
Direct Conversion of Halogen-Containing Wastes to Borosilicate
Glass
Authors: Forsberg C. W. , Beahm E. C. , Rudolph J. C. 
Published: September 2012

ABSTRACTGlass has become a preferred waste form worldwide for radioactive wastes;
however, there are limitations. Halogen-containing wastes can not be
converted to glass because halogens (chlorides, fluorides, etc.) form
poor-quality waste glasses. Furthermore, halides in glass melters often form
second phases that create operating problems. A new waste vitrification
process, the Glass Material Oxidation and Dissolution System (GMODS),
removes these limitations by converting halogen-containing wastes into
borosilicate glass and a secondary, clean, sodium-halide stream.