bluuebunny/crossref_metadata_2025_split huggingface dataset:
Removal of Plasma-Etch-Induced Polymers from Submicron Via Holes by Excimer Laser Ablation
Authors: Lu Y. F. , Lee Y. P. , Zhou M. S. 
Published: April 2011

AbstractA relatively new approach in removing the sidewall and bottom polymers resulting from reactive ion etching of via holes, using a non-contact dry excimer laser cleaning technique has been investigated. Pulsed excimer laser ablation at 248 nm has been found to be capable of removing the via-etch-induced polymers at fluences limited by the damage threshold of the underlying Al-Cu metal film with TiN anti-reflective coating of 250-280 mJ cm-2. A fluence window of 150-200 mJ cm-2 for efficient laser cleaning is also determined from the ablation rate data using the relation in the limit of Beer's law absorption. Experimental results have also shown that the ablation rate when irradiating at an angle is not only comparable to that at vertical incidence, but even register higher values for most of the ablation rate data obtained. An optimum incident angle for laser cleaning of 45° can be determined from the results.
New Ceramic Cluster Materials by Laser Ablation and Reaction
Authors: Froben Friedrich W. , Lu Yimin 
Published: April 2011

AbstractLaser ablation of metals and reaction with hydrocarbon produces clusters of metal carbides. Metal precursors are from group IVb to VIb of the periodic system. The mass distribution is analysed by TOF in the gas phase. The clusters are deposited on carbon and investigated by TEM and STM. The materials are very hard and very flat and include Ti-C, Zr-C, V-C, Nb-C, and TaC.
Spectroscopic Study of Pulsed Laser Induced Plasma from Aluminum Surface
Authors: Lu Y. F. , Tao Z. B. , Hong M. H. , Chan D.S.H. , Low T.S. 
Published: April 2011

AbstractOptical emission spectrum of aluminum plasma induced by a 1064 nm Nd:YAG laser is investigated by an Optical Multichannel Analyzer (OMA). Spectroscopic study shows that more number of Al, Al+, and Al++ spectral lines can be observed with increasing the incident laser fluence. Al, Al+, Al++ spectral lines are also observed successively with high fluence. The atomic spontaneous radiation is analyzed to interpret the calibrated plasma spectrum. The laser energy threshold for the appearance of excited Al, Al+, and Al++ spectral lines are about 0.8, 1.0 and 1.5 J/cm2 respectively. Assuming LTE (Local Thermodynamic Equilibrium) conditions, the plasma density is derived to be in the range of 0.7×1017 to 2×1017 cm-3 from the profiles of Al+ (358.7 and 286.1 nm) spectral lines with different gated times and incident laser fluences. The plasma temperature is also estimated to be 4000 ~ 8000 K, from relative intensities of two different Al I spectral lines (309.2 and 396.2 nm) with different fluence.
From Solid State Diffusion to Configurational Kinetics
Authors: Martin G. , Athènes M. , Desgranges C. , Nastar M. , Soisson F. 
Published: April 2011

ABSTRACTA single model is proposed to describe the cohesive energy and the vacancy jump frequencies as a function of the alloy configuration at the atomic level. The very same model therefore yields both equilibrium and kinetic properties, close and far away from equilibrium. The model is handled at two levels of approximation: Monte Carlo techniques and mean-field type approximations. The model yields equilibrium properties (including the transport coefficients and complex diffusion mechanisms in ordered compounds close to equilibrium) as well as the kinetic path for phase separation, with or without ordering. This allows to identify specific effects of the vacancy diffusion mechanism on the kinetic path for alloy decomposition. Here, we summarise the main results of the above approach.
Crystalline Structure Around the Single Vacancy in Silicon: Formation Volume and Stress Effects
Authors: Antonelli A. , Kaxiras Efthimios , Chadi D. J. 
Published: April 2011

ABSTRACTThe crystalline structure surrounding a single neutral vacancy in silicon is investigated through extensive first-principles total-energy calculations. The results indicate the existence of two distinct distortions of the lattice around the vacancy with essentially the same formation energies at zero pressure, but, however, with different formation volumes. The effect of hydrostatic and biaxial stresses on the relative concentration of each distortion is discussed, suggesting experimental ways to investigate the crystalline structure around the single vacancy and its role as a mediator of atomic diffusion in silicon.
Interdiffusion Behavior of Si/Si1−x Gex. Layers in Inert and Oxidizing Ambients
Authors: Griglione Michelle , Anderson Tim , Haddara Yaser , Law Mark , Jones Kevin 
Published: April 2011

ABSTRACTInterdiffusion of Si/Si0.85Ge0.15 heterojunctions subjected to annealing in inert and oxidizing ambients was investigated as a function of temperature (900 to 1200 °C) and time, allowing comparison between intrinsic diffusion and diffusion under interstitial injection. The Ge diffusivity was extracted using the process simulation program FLOOPS. A time-independent diffusivity was observed for all temperatures. The calculated Ge diffusivity in oxidizing ambient was comparable to that in inert ambient indicating that the interstitial concentration plays a minimal role in interdiffusion. A fractional interstitial component, f1, equal to 0.10 is estimated for annealing temperatures in the range 900 to 1100 °C, while f1 increases to approximately 0.17 at 1200 °C. This may indicate a change in diffusion mechanism at a temperature greater than 1100 °C
Ultra Shallow Junction Formation by B+/BF2+ Implantation at Energy of 0.5 KEV
Authors: Kase M. , Kikuchi Y , Niwa H. , Kimura T. 
Published: April 2011

ABSTRACTThis paper describes ultra shallow junction formation using 0.5 keV B+/BF2+ implantation, which has the advantage of a reduced channeling tail and no transient enhanced diffusion. In the case of l × 1014 cm−2, 0.5 keV BF2 implantation a junction depth of 19 nm is achieved after RTA at 950°C.
A Quasi-2d Model for Reverse Short Channel Effect
Authors: Zhu Huilong 
Published: April 2011

ABSTRACTA new physically-based model for reverse short channel effects has been developed. This kinetic model considers three species: neutral interstitial, immobile dopant and mobile interstitial-dopant pairs. To consider ion-implantation damage and stress effects on the Si/SiO2 interface, a non-uniform sink strength at the Si/SiO2 interface for interstitials has been assumed. ALAMODE, a PDE solver, was used to solve the model. Lateral boron distributions of NMOS devices in the channel near the Si/SiO2 interface have been simulated. Significant boron pile-up was found at the gate edges which is in quantitative agreement with the doping profiles extracted from experimental C-V data. The mechanism of the B diffusion in the channel region is discussed.
Activation Enthalpy of Sb Diffusion in Biaxially Compressed SiGe Layers
Authors: Kuznetsovt A. Yu. , Cardenast J. , Svenssont B. G. , Larsen A. Nylandsted , Hansen J. Lundsgaard 
Published: April 2011

ABSTRACTEnhanced Sb diffusion in biaxially compressed Si1-x-Gex layers is observed. Assuming the prefactors to be stress independent the Sb diffusion coefficients in biaxially compressed Si0.9Ge0.2 and Si0 8 Ge0.2 were extracted as 0.4 × 102 exp[− (3.98(eV) ± 0.12)/kT] and 1.3x 102 exp[− (3.85(eV) ±0.12)/kT] cm2 /s, respectively. The activation volume of Sb diffusion in Si1-xGex (x ≤ 0.2) is estimated to be close to ω, where ω is the volume corresponding to a silicon lattice site.
Lateral Ordering of Self-Assembled Ge Islands
Authors: Zhu Jian-Hong , Brunner K. , Abstreiter G. 
Published: April 2011

AbstractTwo-dimensionally ordered arrays of Ge islands are realized by molecular beam epitaxy on vicinal Si(001) surfaces with regular ripples. Deposition of a 2.5 nm Si0.55Ge0.45/10 nm Si multilayer on vicinal Si(001) surfaces gives rise to the formation of regular ripples with a typical period of 100 nm, due to step-bunching. The ripples lead to the long-range line-up of the Ge islands along their direction, while the strong repulsive interaction between the dense Ge islands determines their relative arrangement on different step bunches of a ripple. The ordering pattern can be controlled by the Ge coverage as well as the direction of the ripples. The Ge islands show a narrow size distribution with the lateral size limited by the ripple periodIn contrast, when deposited directly on well-prepared biatomic-stepped vicinal Si(001) surfaces under the same growth conditions, only weak ordering of Ge islands along the step direction is achieved. No ordering of Ge islands has been observed, when a flat Si(001) surface is employed, where no obvious step-bunching occurs.The results promise efficient control on the position and size of self-assembled and selfordered Ge islands by the steps prepared on vicinal surfaces.
Photoluminescence In Strain Compensated Siisigec Multiple Quantum Wells
Authors: Hartmann R. , Gennser U. , Grützmacher D. , Sigg H. , Müller E. , Ensslin K. 
Published: April 2011

AbstractThe effect of strain compensation on the band gap and band alignment of Si/SiGeC MQWs is studied by photoluminescence (PL) spectroscopy. Evidence for type-I band alignment of strain reduced SiGeC MQWs is found. Values for the conduction and valence band offsets are given. A band gap reduction for exactly strain compensated SiGeC compared to compressive SiGeC is observed. This behavior is interpreted in terms of strain induced splitting and confinement shifts of the quantum well states. A good agreement between the model and the PL data is obtained.
Influence Of Growth Conditions On The Thermal Quenching Of Photoluminescence From Sige/Si Quantum Structures
Authors: Buyanova I. A. , Chen W. M. , Ni W.-X. , Hansson G. V. , Monemar B. 
Published: April 2011

AbstractIn this work we study effects of growth temperature and use of surfactant during growth on thermal quenching of photoluminescence (PL) from SiGe/Si quantum wells (QWs) grown by molecular beam epitaxy (MBE). We show that although all investigated structures demonstrate intense and sharp excitonic emissions from the SiGe QWs at liquid helium temperature, thermal quenching of this PL critically depends on the growth conditions. In particular, the use of low (⁤ 550°C) growth temperatures or employing Sb as a surfactant during high temperature (620°C) growth considerably degrades the PL thermal quenching behaviour by introducing some competing quenching processes with low activation energies of about 5 meV. The optimum growth conditions judging from the PL thermal behaviour are realised during high temperature growth without surfactant (620°C). Even higher growth temperature is shown to be required during surfactant mediated growth to improve the thermal quenching behaviour. From optically detected magnetic resonance (ODMR) studies, the competing quenching processes are attributed to a thermal activation of non-radiative defects introduced during either low-temperature MBE growth or during surfactant-mediated growth.
A Novel Layer-By-Layer Hetero-Epitaxy Of Germanium On Silicon (100) Surface
Authors: Sugahara S. , Matsuyama M. , Hosaka K. , Ikeda K. , Uchida Y. , Matsumura M. 
Published: April 2011

AbstractLayer-by-layer hetero-epitaxy of Ge has been successfully demonstrated on the Si(100) surface by combining the initial IML-Ge film growth on the Si surface and the successive Ge atomic-layer-epitxy (ALE), for the first time. The former was achieved using the substrate temperature modulation with alternate exposures of GeCL4 and atomic H, and the later was established by cyclic exposures of (CH 3)2GeH2 and atomic H under isothermal conditions. XPS measurements confirmed a discrete and uniform increase in the grown Ge film thickness with one monolayer/cycle step up to the critical Ge thickness, and no C contamination at the Ge/Si interface. Critical exposure for the saturated Ge adsorption was different from that for the homo-ALE on the bulk Ge surface.
Metalorganic Molecular Beam Epitaxy of GaAsP for Visible Light-Emitting Devices on Si
Authors: Yoshimoto M. , Saraie J. , Yasui T. , HA S. , Matsunami H. 
Published: April 2011

AbstractGaAs1–xPx (0.2 <; x < 0.7) was grown by metalorganic molecular beam epitaxy with a GaP buffer layer on Si for visible light-emitting devices. Insertion of the GaP buffer layer resulted in bright photoluminescence of the GaAsP epilayer. Pre-treatment of the Si substrate to avoid SiC formation was also critical to obtain good crystallinity of GaAsP. Dislocation formation, microstructure and photoluminescence in GaAsP grown layer are described. A GaAsP pn junction fabricated on GaP emitted visible light (˜1.86 eV). An initial GaAsP pn diode fabricated on Si emitted infrared light.
Fabrication of Integrated Ferrite/Semiconductor Circulators
Authors: Oliver S. A. , How H. , Shi P. , Hu W. , Kozulin I. , McGruer N. E. , Zavracky P. M. , Vittoria C. 
Published: April 2011

AbstractIntegrated planar circulator circuits operating at frequencies near 10 GHz have been fabricated using transferred film techniques. A 100 micrometer thick film of single-crystal yttrium iron garnet was transferred onto a metallized silicon die using a bond and lap-back process. The alloy bond layer was formed through a low-temperature solid-liquid interdiffusion process using films of indium and gold. This bond layer proved of sufficient strength to permit removal of the gadolinium gallium garnet substrate through grinding, but chemical analysis of the bond shows that interdiffusion occurs between the bond and metallization layers. These integrated gamet/silicon circulator circuits show good device performance.
In Situ Monitoring of III-V Processing
Authors: Terry F. L. 
Published: April 2011

AbstractFabrication of high performance III-V devices and integrated circuits depends on careful control of layer thicknesses and compositions in the as-grown epitaxial layers and in the etching of these layers. The relatively high value of compound semiconductor devices (compared with high-volume Si devices) makes the use of advanced process control (with expensive in situ sensors) potentially advantageous. Considerable attention has been given to the problems of realtime feedback control of MBE growth systems. In this paper, I will discuss experiences with use of both in situ and ex situ monitors for controlling reactive ion etching (RIE) of III-V materials. Specific examples from an electron cyclotron resonance (ECR) RIE base contact etch from an AlInAs/GalnAs HBT process will be given. The relative merits of reflection-based wafer sensors vs. process state sensors (optical emission spectroscopy and mass spectroscopy) will be discussed. The unique opportunities and problems associated with the III-V materials and required etch processes will be contrasted to implementation of advanced wafer state endpoint detection schemes in Si and flat panel display processes. Specific problems and solutions from our research which I will discuss include chamber seasoning effects on the drift of optical emission based endpoint detection schemes and signal processing techniques for accounting for this drift, modeling of the optical dielectric function of the compounds of interest vs. composition, and the effects of surface roughness on optical thickness measurements.
In Situ Control of Wet Etching Using Spectroscopic Ellipsometry
Authors: Cho Sang-Jun , Snyder P. G. 
Published: April 2011

AbstractEtching of a GaAs/Al0.3Ga0.7As/GaAs heterostructure in a nonselective etch solution of 25:1:75 (citric acid: H2O2:H2O) was studied in-situ using real time spectroscopic ellipsometry (RTSE). Etch rates for GaAs and AIGaAs of 15.3 nm/min and 17.6 nm/min, respectively, were determined by numerically fitting RTSE data. RTSE was successfully used to stop the etch after removal of the thin GaAs cap, while removing very little of the underlying AlGaAs layer. In addition, etch depth into the AIGaAs layer was accurately controlled, using RTSE to stop the etch with 100 nm remaining. Finally, RTSE data for wet etching of a patterned sample (75% coverage with photoresist) showed similar behavior to that for the unpattemed sample.
Mobility characterization of p-type and n-type strained sil-x-yGexcy/Si Epilayer hall devices
Authors: Petersoa Jeff J. , Hunt Charles E. , Zappe Stefan F. , Obeneier Ernst , Westhoff Richard , Robinson McDonald 
Published: April 2011

AbstractMobilities in Si1-x-yGex Cy layers were measured using mesa etched Van der Pauw structures for alloy layers with 0 < x < 0.30 and 0 < y < 0.02 and doping levels of 1015 < N < 1018 cm-3. Mobilities in Si1-x-yGex Cy layers with x = 0.27 were found to approach Si mobilities for both μn and μp.While electron mobilities in phosphorous-doped SiGeC decrease with doping concentration, hole mobilities in boron-doped SiGeC increase with doping level, indicating ionized impurity scattering is not dominant for μp over the temperature range studied.
Kinetic Monte Carlo Simulation of Dislocation Dynamics
Authors: Lin Karin , Chrzan D. C. 
Published: April 2011

AbstractA kinetic Monte Carlo simulation of dislocation motion is introduced. The dislocations are assumed to be composed of pure edge and screw segments only, and are assumed to be confined to a fixed lattice. The stress and temperature dependence of the dislocation velocity is studied. It is also noted that the simulated dislocations display kinetic roughening.
Shock Wave Response of Materials at Different Length Scales
Authors: Gupta Y.M. 
Published: April 2011

AbstractAfter a brief introduction to shock wave propagation in solids, recent experimental developments to understand the real time response of shocked materials at various length scales are outlined. Results from two representative studies are summarized: xray diffraction to examine elastic-plastic deformation in shocked LiF crystals; and picosecond optical absorption to examine structural transformation in shocked CdS crystals. Issues related to examining material processes at different length scales in shock wave experiments are discussed briefly.
Modeling of Segregation and Microstructural Evolution near Grain Boundary in FE-CR-NI Alloy Under Irradiation
Authors: Sakaguchi N. , Watanabe S. , Takahashi H. 
Published: April 2011

AbstractWe have investigated the solute segregation and simultaneous evolution of extended defects in an Fe-Cr-Ni alloy during irradiation by computer simulation. It sheds a light on the accomplishment of performing “the combined total calculation” or “the muliscale modeling” which deals with both radiation-induced segregation and various kinds of internal sink evolution. The formation of dislocation-free zone (DLFZ) was predicted in the vicinity of a grain boundary. It indicated that DLFZ formation is controlled by solute diffusional process via point defects diffusion near the grain boundary and the activation energy obtained by the width of DLFZ corresponds to the half of the value of the radiation-enhanced solute diffusivity.
Kinetic Lattice Monte Carlo Simulations of Cascade Aging in Iron and Dilute Iron-Copper Alloys
Authors: Wirth B. D. , Odette G. R. 
Published: April 2011

AbstractNeutron hardening and embrittlement of pressure vessel steels is due to a high density of nm scale features, including copper-manganese-nickel rich precipitates and what are generally believed to be defect cluster-solute complexes. It has been postulated that the sub nanometer defect cluster-solute complexes form directly in displacement cascades. Cluster-complexes that are thermally unstable mediate the effect of flux on embrittlement kinetics. Larger cluster-complexes, that are relatively thermally stable for irradiation times up to 1 Gs, cause embrittlement in low copper steels. Robust characterization of these two types of so-called matrix defects has been an elusive goal. In this work, Kinetic Lattice Monte Carlo (KLMC) simulations of the long term evolution of the vacancy-rich cascade core regions were carried out for both pure iron and dilute iron-copper alloys at the nominal irradiation temperature of 563°K up to times when the vacancy clusters completely dissolve. Energetics were based on lattice embedded atom method potentials. Special time scaling and pulse annealing techniques were used to deal with the enormous range of inherent time scales involved, viz., rapid free vacancy jumps to slow emission from large complexes. Three-dimensional clusters rapidly form, containing a wide range of vacancies, as well as copper atoms in alloys. Small complexes are very mobile and growth takes place primarily by coalescence. The vacancy clusters ultimately dissolve at times from less than 0.1 to more than 100 MS. These simulations support the hypotheses that cascade cluster-complexes constitute both thermally stable and unstable matrix defect features.
Irradiation-Enhanced Diffusion in Metallic Glasses
Authors: Schuler T. , Scharwaechter P. , Frank W.F.J. 
Published: April 2011

AbstractThe influence of irradiation with particles (H+, He+, 15N+) on the self-diffusion in relaxed metallic glasses (59Fe in Fe91Zr9, 59Fe in Co58Fe5Ni10Si11B16, 95Zr in Fe24Zr76) has been investigated by means of the radiotracer technique using ion-beam sputtering for serial sectioning of the specimens. Combination of the results of these experiments with accompanying molecular-dynamics simulations not only leads to an understanding of a novel phenomenon of irradiation-enhanced diffusion observed on these materials, but also confirms and refines our previous view that, in the absence of irradiation, diffusion in relaxed metallic glasses occurs by collective diffusion mechanisms not involving intrinsic point defects as diffusion vehicles.
Structural Analysis of a Completely Amorphous 238Pu-Doped Zircon by Neutron Diffraction
Authors: Fortner Jeffrey A. , Badyal Yaspal , Price David C. L. , Hanchar John M. , Weber William J. 
Published: April 2011

AbstractThe structure of a completely amorphous zircon was determined by time-of-flight neutron diffraction at Argonne's Intense Pulsed Neutron Source (IPNS). The sample of metamict zircon (ZrSiO4), initially doped to 8.85 weight percent 238pu, had been completely amorphized by alpha-recoil damage since its synthesis in 1981 at the Pacific Northwest National Laboratory (PNNL). The measured diffraction structure factor, S(Q), indicated a completely amorphous sample, with no signs of residual zircon microcrystallinity. The pair distribution function obtained indicated that the structure was that of an oxide glass, retaining the Si–O, Zr–O, and O–O bond lengths of crystalline zircon.
Cathodoluminescence Microanalysis of Electron Irradiation Damage in Wide Band Gap Materials
Authors: Kalceff M.A. stevens , Phillips M.R. , Toth M. , Moon A.R. , Jamieson D.N. , Orwa J.O. , Prawer S. 
Published: April 2011

AbstractCathodoluminescence (CL) microanalysis (spectroscopy and microscopy) in an electron microscope enables both pre-existing and irradiation induced local variations in the bulk and surface defect structure of wide band gap materials to be characterized with high spatial (lateral and depth) resolution and sensitivity. CL microanalytical techniques allow the in situ monitoring of electron irradiation induced damage, the post irradiation assessment of damage induced by other energetic radiation, and the investigation of irradiation induced electromigration of mobile charged defect species. Electron irradiated silicon dioxide polymorphs and MeV H+ ion implanted Type Ila diamond have been investigated using CL microanalytical techniques.