bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-Rate Etching of Mn-Zn Ferrite by Laser-Induced Chemical Reaction in CC12F2 Atmosphere
Authors: Lu Y. F. , Takai M. , Nagatomo S. , Namba S. 
Published: March 2011

AbstractMaskless dry etching of Mn-Zn ferrite in dich1orodif1uoromethane (CC12F2) by Ar+-ion laser (514.5 nm-line) irradiation has been investigated to obtain high etching rates and aspect-ratios of etched grooves. The etching reaction was found to be thermochemical and caused by Cl radicals thermally decomposed from CCl2F2 gas. High etching rates of up to 360 μm/s, which is about one order of magnitude higher than that in a CCl4 gas and even higher than that in a H3PO4 solution, have been achieved. A high aspect-ratio of up to 12 was obtained. Definite gas pressure and dwell time are necessary to fabricate a smooth groove.
Effects of Processing Parameters on the Laser Deposition of High Temperature Superconducting Thin Films
Authors: Nogar N. S. , Castain R. , Dye R. C. , Foltyn S. , Muenchausen R. E. , Wu X. D. 
Published: March 2011

AbstractY2O3 pressed powders were ablated by pulses from a XeCl excimer laser, operating at 308 nm, 150 mj/pulse, ≈15 nsec/pulse and 20 Hz. Emission spectra from Y∗ and YO∗ were recorded as a function of ambient oxygen pressure in the range 10−5 − 4×10−1 Torr, at a laser fluence of ≈ 4 J/cm2. A kinetic model is developed to describe the results, and the application to production of laser-deposited high-temperature superconductor thin films is discussed.
Implantation of 1.5 MeV Ag+ Ions in Silica Glass
Authors: Fukumi K. , Chayahara A. , Hayakawa J. , Satou M. 
Published: March 2011

AbstractAg+ ions were implanted in silica glass at an acceleration energy of 1.5MeV. It is found that Ag atoms are present in both the metallic and ionic states. Ag atoms in the metallic state increase when the Ag atom concentration increases. It is shown that the structure of damaged glass recovers monotonically from the surface to the inside of the glass. The state of the Ag atoms does not depend on the glass structure damaged by ion implantation.
High Dose Ion Implantation for the Synthesis of Si1−xGex Alloys
Authors: Howard D. J. , Paine D. C. , Stoffel N. G. 
Published: March 2011

AbstractHigh dose ion implantation followed by solid phase epitaxy has been investigated for use in the synthesis of defect-free graded alloys of Si1−xGex. Two implanted alloy systems were studied: (i) 200 keV 74Ge into <001> Si to form Si-rich alloys and (ii) 150 keV 29Si into <001> Ge to form Ge-rich alloys. After regrowth by solid phase epitaxy the Ge-rich alloys are strained in tension while the Si-rich alloys are in compression and, as a result, strain relaxation is anticipated above a critical dose. We report that solid phase epitaxy at 550°C following implantation of Si into <001> Ge at an energy of 150 keV allowed the defect-free regrowth of alloys with peak concentrations of 11 ± 2 at. % Si (fluence of 7.7 × l016/cm2). Ge was implanted at 200 keV into <001> Si to a peak concentration of 7 at. % (fluence of 3.6 × l016/cm2) and was regrown without the introduction of defects whereas samples implanted to a peak concentration of 13 at. % (fluence of 5.3 × l016/cm2) contained a high density of stacking faults. These experimental observations are compared to theoretical predictions that are based on the strain energy approach.
Characteristics of 56 Mev Oxygen Implantation into Si and III-V Semiconductors
Authors: Pearton S. J. , Jalali B. , Poate J. M. , Fox J. D. , Kemper K. W. , Magee C. W. , Jones K. S. 
Published: March 2011

AbstractHigh energy (56 MeV) oxygen implants into Si, GaAs and InP give rise to sharp, non-Gaussian depth profiles with the distributions skewed towards greater depths. This skewness is probably the result of channeling, and it is a common feature of MeV implants into semiconductors. The ratio of the peak concentration in the depth profile to the concentration at the surface is ≥103 for each material, and the full width at half maximum of each profile is ∼2 μm. The experimental projected ranges for the oxygen are ∼31 μm in GaAs, ∼36 μm in InP and ∼46 μm in Si. These are ∼10% larger than the values predicted by the PRAL code. The photoluminescence intensity from the top 1 μm from the surface of both GaAs and InP is reduced by more than an order of magnitude for 56 MeV oxygen implants at a dose of 1.3 × 1015 cm−2, due to point defect introduction in this region. Potential applications for these high energy implants in electronic and photonic device fabrication will be discussed.
Characterization of Ion-Implanted Aluminum and Iron by Spectroscopic Ellipsometry
Authors: Brodkin J. S. , Franzen W. , Culbertson R. J. , Williams J. M. 
Published: March 2011

AbstractThe change in the optical constants of aluminum alloy and iron samples caused by implantation with nitrogen and chromium ions has been investigated by spectroscopic ellipsometry. The objective is to develop a method for simple, non-destructive characterization of ion-implanted metals.
Suppression of Crystal Nucleation in Amorphous Si Thin Films by High Energy Ion Irradiation at Intermediate Temperatures
Authors: Im James S. , Shin Jung H. , Atwater Harry A. 
Published: March 2011

AbstractIn situ electron microscopy has been used to observe crystal nucleation and growth in amorphous Si films. Results demonstrate that a repeated intermediate temperature ion irradiation/thermal annealing cycle can lead to suppression of nucleation in amorphous regions without inhibition of crystal growth of existing large crystals. Fundamentally, the experimental results indicate that the population of small crystal clusters near the critical cluster size is affected by intermediate temperature ion irradiation. Potential applications of the intermediate temperature irradiation/thermal anneal cycle to lateral solid epitaxy of Si and thin film device technology are discussed.
Lattice Disordering, Phase Transition, and Substrate Temperature Effects in MeV-ION-Implanted III-V Compound Semiconductors
Authors: Xiong Fulin , Tsai C. J. , Vreeland T. , Tombrello T. A. 
Published: March 2011

AbstractAn experimental study of lattice disordering, the crystalline-to-amorphous (c-a) phase transition, and substrate temperature effects in MeV-ion-implanted III-V compound semiconductor crystals is presented. A comparison has been made between the GaAs and InP systems, which have been implanted with 2 MeV oxygen ions at either room temperature (RT) or near liquid nitrogen temperature (LT). A strong in situ dynamic annealing has been found in the RT implanted GaAs, and the LT implanted GaAs exhibits heterogeneous (at the end-of-range of the ions) and homogeneous (at the subsurface region) c-a phase transitions. In InP crystals, in situ annealing is much less pronounced in RT implantation, and dose-dependent damage nucleation and layer-by-layer amorphization take place. LT implantation results in lattice disordering and phase transition with a critical dose at least one order lower than that for GaAs. The mechanisms and kinetics of lattice disordering by ion irradiation are also discussed.
Atomistic Simulation of Radiation-Induced Amorphization of the B2 Ordered Intermetallic Compound NiTi
Authors: Sabochick Michael J. , Lam Nghi Q. 
Published: March 2011

AbstractAmorphization of the B2 intermetallic compound NiTi under electron irradiation has been investigated using molecular dynamics. The effect of irradiation was simulated using two processes: 1) Ni and Ti atoms were exchanged, resulting in chemical disorder, and 2) Frenkel pairs were introduced, leading to the formation of stable point defects and also chemical disorder upon mutual recombination of interstitials and vacancies. After ∼0.1 exchanges per atom, the first process resulted in an energy increase of approximately 0.11 eV/atom and a volume increase of 1.91%. On the other hand, after introducing ∼0.5 Frenkel pairs per atom, the second process led to smaller increases of 0.092 eV/atom in energy and 1.43% in volume. The calculated radial distribution functions (RDFs) were essentially identical to each other and to the calculated RDF of a quenched liquid. The structure factor, however, showed that long-range order was still present after atom exchanges, while the introduction of Frenkel pairs resulted in the loss of long-range order. It was concluded that point defects are necessary for amorphization to occur in NiTi, although chemical disorder alone is capable of storing enough energy to make the transition possible.
Copper Laser Induced Chemical Vapor Deposition of al Films
Authors: Yankova M. I. , Shanov W. , Ivanov B. 
Published: March 2011

AbstractThe focused output from a copper laser (λ = 510nm) has been used for direct writing of Al on silicon substrates by pyrolitical decomposition of trimethilaluminum (TMA). These results demonstrate that direct writing can be accomplished at room temperature by a single-step deposition process induced by a single light source. For a laser power density between 5 and 50 kW cm−2, the widths of the stripes varied between 60 and 200 μm with corresponding thickness between 0.5 and 0.8 μm. The width of the stripes proved to be independent of the scanning velocity, Vs, within the range 50 μm s−1 < Vs < 300 μm s−1. The analysis included scanning electron microscopy (SEM) to study the film morphology, a step profiler to evaluate the thicknesses and the profiles of the stripes, and energy dispersive spectroscopy (EDS) to provide their chemical compositions.
Optical Effects Induced by the Multilayer Nature of SOI Films During Transient Thermal Processing with a Radiant Line Heat Source.
Authors: Wong Peter Y. , Miaoulis Ioannis N. , Zavracky P. 
Published: March 2011

AbstractRadiation heat transfer has been found to have the greatest Impact on the quality of the thin recrystalllzed silicon film during zone-melting recrystallizatlon (ZMR) processing. This study focused on the radiation effects during ZMR with an Infrared radiant line heat source such as a graphite strip heater. The multilayer nature of the capped sllicon-on-tnsulator (SOI) structure Induces complex optical effects which affect the temperature distribution during processing. A two dimensional numerical model of the ZMR process has been developed using a finite difference scheme. The effect of the radiant line heat source’s emission into the wafer has been modeled with a matrix method using Fresnel coefficients. A numerical parametric study was conducted to observe the effects of varying the thickness of the different layers In a capped SOI wafer on the maximum temperature and melt width attained. Results indicate that the variation of either the capping or insulating silicon oxide layer causes significant fluctuations of the reflectivity and temperature profile of the film. Increasing the thickness of the Si layer results in a nearly linear increase in temperature and melt width after complete melting. Layering schemes that are sensitive to small variations In thickness that may result in large changes in reflectivity were Identified.
The Effect of Photoexcitation on Formation of Radiation Defects in Si
Authors: Mordkovich V. N. , Danilin A. B. , Erokhin Yu. N. , Boldyrev S. N. 
Published: March 2011

AbstractPhotoexcitation of the Si electronic subsystem during ion implantation was found to be able to control radiation damage accumulation. Conditions when additional light illumination during ion bombardment suppresses radiation defect formation are determined. The model of effect observed taking into account recombination of nonequilibrium electron and holes is proposed. Coefficient between the change in amount of damage accumulated and the rate of nonequilibrium charge carriers generation is estimated.
UV Laser Ablation of Ferroelectrics
Authors: Haglund R. F. , Arps J. H. , Tang K. , Niehof A. , Heiland W. 
Published: March 2011

AbstractWe have investigated laser ablation of excited atoms from the ferroelectrics LiNbO3 and KNbO3 at 308 nm. Comparisons of the yields for O*, K* and Nb* from pure and undoped KNbO3 show the effects of changing intensity, surface condition and irradiation time on the yield of excited atoms. Below about 20 GW cm−2, the mechanisms for production of excited atoms differ among the various species; above that intensity, the production of a dense electron-hole plasma appears to impart a collective character to the ablation mechanism.
Optical Monitoring of Y-Ba-Cu-O Ion Beam Sputtering
Authors: Klein J.D. , Yen A. 
Published: March 2011

AbstractEmission spectra resulting from ion beam sputtering an Y-Ba-Cu-O target were observed as a function of beam voltage and time using an optical multichannel analyser. The observed spectra were clean with several peaks attributed to each of Y, Ba, and Ar. A well defined O peak and a weak CuO peak were available for comparison. The intensities of the cation peaks were linear with respect to beam voltage above 450 V. Presputtering of a previously stored target was characterized by the diminishment of an initially large H peak as the cation peaks emerged.
KrF Excimer Laser Direct Writing of Titanium Lines: Modeling and Application to the Fabrication of Ti:Linbo3 Waveguides
Authors: Meunier M. , Lavoie C. , Boivin S. , Izquierdo R. , Desjardins P. , Najafi S. I. 
Published: March 2011

AbstractThe deposition of titanium lines by KrF excimer laser direct writing on lithium niobate (LiNbO3) has been investigated. A detailled study of the line profile has been performed since this is critical in the fabrication of Ti:LiNbO3 optical waveguides. We show that at a low power density E, the maximum thickness t is proportional to E, while increasing E leads to the diffusion of Ti into LiNbO3 resulting in a saturation and even a decrease in thickness. Preliminary results on Ti:LiNbO3 optical waveguides show that their characteristics are similar to those made by conventional methods.
Similarities and Differences in the Mechanisms of High and Low Energy Ion Mixing
Authors: Cheng Yang-Tse , Simko Steven J. , Militello Maria C. , Dow Audrey A. , Auner Gregory W. , Alkaisi M. H. , Padmanabhan K. R. 
Published: March 2011

AbstractHigh energy ion mixing occurs when an ion beam of a few hundred keV bombards an interface under the surface. Low energy ion mixing arises when an ion beam of a few keV bombards an interface near the surface during, for example, sputter depth profiling and low energy ion assisted deposition. At low temperatures, the rate of both high and low energy ion mixing can be influenced by thermodynamic parameters, such as the heat of mixing and the cohesive energy of solids. These effects are demonstrated by ion mixing experiments using metallic bilayers consisting of high atomic number elements. A model of diffusion in thermal spikes is used to explain this similarity. Low energy ion mixing can also be strongly affected by surface diffusion and the morphological stability of thin films. These effects are illustrated using results obtained from sputter depth profiling of Ag/Ni bilayers at elevated temperatures. High energy ion mixing at low temperatures can be influenced by the anisotropic momentum distribution in a collision cascade as seen from a set of marker experiments to determine the dominant moving species in high energy ion mixing. These similarities and differences between high and low energy ion mixing illustrate the diversity of ion-solid interactions.
Schottky Properties of Tungsten Compounds Refractory Contacts on n-GaAs Fabricated by Ion Beam Assisted Deposition
Authors: Park C. S. , Lee J. S. , Lee J. W. , Kang J. Y. , Lee J. Y. 
Published: March 2011

AbstractA low energy ion beam assisted deposition (IBAD) technique has been developed to fabricate refractory W-Si-N films for the application to gate electrode of GaAs metal-semiconductor field effect transistors( MESFETs ). Thermal stability of the IBAD refractory metal/n-GaAs interface was investigated by examining the microstructure and Schottky diode characteristics. The Schottky barrier heights of 0.71, 0.84, and 0.76 eV were obtained after thermal annealing at 850°C for the W/, WN0.27/, and WSi0.3N0.4/GaAs diodes, respectively, and these values are comparable to those of the best results published with conventional reactive sputtering. While some crystalization of the deposit and reaction between film and substrate at the interface were observed with TEM for the W/ and WN/GaAs contacts annealed at 800°, the WSiN film remained amorphous and showed clear interface with the GaAs substrate without significant morphological change. The WS0.3N0.4/GaAs diode showed good thermal stability of Schottky barrier heights with only 20 meV variation in the temperature range between 700 and 850°C, and that is proposed to be due to the stable microstructure.
Quantitative Studies on the Evolution of the Polysilicon/Silicon Interfacial Oxide Upon Annealing
Authors: Ajuria Sergio A. , Reif Rafael 
Published: March 2011

ABSTRACTPolysilicon/silicon interfacial oxides are shown by cross-sectional Transmission Electron Microscopy studies to agglomerate upon annealing. In addition to presenting highlights of microscopy results, we report on electrical characterization data obtained from Cross-Bridge Kelvin Resistors. Resistor data not only support a model for agglomeration proven on microscopy data, but also allow for a quantitative macroscopic understanding of the agglomeration of polysilicon/silicon interfacial oxides over a wide range of times and temperatures.
Lpcvd Polycrystalline Silicon Thin Films: The Evolution of Structure, Texture and Stress
Authors: Krulevitch P. , Nguyen Tai D. , Johnson G. C. , Howe R. T. , Wenk H. R. , Gronsky R. 
Published: March 2011

ABSTRACTAn investigation of undoped LPCVD polycrystalline silicon films deposited at temperatures ranging from 605 to 700 C and silane pressures from 300 to 550 mTorr revealed large variations in stress with processing conditions and a correlation between stress and texture. TEM and HRTEM analysis show that morphology differences also exist. At lower temperatures (≈605 C) and higher pressures (≈400 mTorr), the films appear to deposit in an amorphous state and crystallize during the deposition to form microstructures characterized by equi-axed grains, tensile residual stress, and a texture with {110} and {11/} (/=2 or 3) components. Higher temperatures (between 620 and 650 C) produce films that nucleate at the Si02 interface, creating a {110} oriented columnar microstructure. At 700 C, the grains are still columnar, but the dominant texture is {100}. Films deposited at temperatures greater than 620 C exhibit compressive stress, and some contain regions of hexagonal silicon. This paper proposes possible causes of the varying stresses, textures, and microstructures in the films.
The Nucleation and Epitaxial Growth of Au and Ag on Thin Silicon Studied With a Scanning Transmission Electron Microscope
Authors: Xu Peirong , Miller Peter , Silcox John 
Published: March 2011

ABSTRACTAn UHV Scanning Transmission Electron Microscope (STEM) has been used to study the nucleation and epitaxial growth of Au and Ag deposited at room temperature on H-passivated thin silicon (111) and (100) substrates. Direct observations of the initial stages of overlayer growth were made using bright field (BF) and annular dark field (ADF) imaging modes. Gold was found to grow on silicon in a quasi-continuous layer mode, while 3D island growth with density as high as 4×1012/cm2 was observed in Ag/Si systems. Electron diffraction studies reveal a good epitaxial relationship for Ag films grown both on silicon (111) and (100) substrates. Diffraction also indicates that Au (111) grows on the silicon (111) surface but the grains may be azimuthally rotated.
Thin Film Growth and Magnetic Properties for Fe/GaAs(100).
Authors: Andrien Bruce A. , Miller David R. 
Published: March 2011

ABSTRACTThin Fe films, 1 nm to 90 nm, have been grown on GaAs (100) substrates in ultra high vacuum, base pressure = 2×l0−8 Pa. The growth of the films has been followed with Auger electron spectroscopy and a recently developed in-situ UHV M/H hysteresis loop tracer. The Auger signal provides an indication as to when the Fe covers the GaAs substrate or when it clusters into three dimensional islands. The magnetic hysteresis loop tracer provides the coercivity and the saturation magnetic moment, from which the saturation magnetization or average film thickness can be obtained. The coercivity of thin films is sensitive to structure, strain, and to the grain size, in analogy to its sensitivity to particle size for small particles. The data show that the coercivity, Hc, as a function of film thickness, is very sensitive to the annealing procedures and to the resulting morphology, continuous versus local clustering of the iron film. Under proper conditions a clear maximum in Hc versus film thickness is observed for these films near 5 nm thickness, in analogy to three dimensional small particle curves.
Investigation of Diamond Particles Grown by Microwave Plasma CVD on Tungsten Wire Tips.
Authors: Stuart Sue-Anne , Prawer Steven , Hoffman Alon , Moodie Alec , Weiser Paul 
Published: March 2011

ABSTRACTLarge diamond particles up to 30μm in diameter have been deposited on W wire tips using Microwave Plasma Chemical Vapour Deposition. Raman, SEM and TEM investigations were all carried out on a single particle. Large growth steps were observed on (100) facets but were absent on the (111) facets. Raman measurements indicated greater crystalline quality for (100) than (111) facets. TEM revealed the (111) facets to be covered with small islands of diamond about 10Å high. The dominant defect was found to be stacking faulting on the {111} planes which gives rise to some hexagonal spacings in the electron diffraction pattern. The results suggest that growth in the <111> and <100> directions are driven by different mechanisms.
Influence of Silicon Substrate Ion Implantation on the Subsequent Microstructure Evolution in Cobalt Silicide Films
Authors: Xiao Z. G. , Honeycutt J. W. , Rozgonyi G. A. 
Published: March 2011

ABSTRACTThe influence of amorphization of the Si substrate by Ge+ implantation on the microstructural evolution of CoSi2 thin films has been investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and four-point-probe measurement. While the silicide films formed on unimplanted or recrystallized Si were similar in formation kinetics, microstructure and resistivity, unique features were found for silicide films formed on amorphized Si. The phase transformation to CoSi2 on amorphized Si was considerably accelerated, the silicide grain size was smaller, and the CoSi2/Si interface was much smoother on the amorphized Si. Direct evidence of grain boundary diffusion induced silicide/Si interface roughness was obtained. The origin of the difference in both the microstructure and kinetics on different Si substrates is explained by the latent energy stored in amorphous Si, increasing the silicide nucleation rate. Weak XRD peaks and different texture were found for the CoSi2 formed on amorphized Si. The facts that the dominant diffusing species during CoSi2 formation is Co, and the new phase was developed in an amorphous medium are thought to be responsible for these phenomena.
X-Ray Diffraction From Surfaces and Interfaces: Atomic Structure and Morphology
Authors: Vlieg E. , Robinson I.K. , van der Veen J.F. 
Published: March 2011

ABSTRACTThe emergence of synchrotron radiation sources has greatly stimulated the use of X-ray scattering in surface science. The absence of multiple-scattering effects allows a straightforward data analysis. In addition to determining geometric structures, it is also possible with X-ray scattering to obtain information on various types of surface disorder. The large penetration depth enables the investigation of interfaces.