bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ordered Structures of Zn1−xFexSe Epilayers Grown on InP and GaAs Substrates
Authors: Park K. , Wei H.- Y. , Salamanca-Riba L. , Jonker B. T. 
Published: March 2011

AbstractWe present evidence for two types of ordered structures, CuAu-I and CuPt, in Zn1−xFexSe (x≈ 0.4) epilayers grown by molecular beam epitaxy. These ordered structures are observed in both electron diffraction patterns and cross-sectional high-resolution lattice images. The CuAu-I ordered structure occurs in Zn1−xFexSe epilayers grown on (001) InP substrates, while the CuPt-type occurs in epilayers grown on (001) GaAs substrates. The ordered structure of Zn1−xFexSe grown on InP substrates consists of alternating ZnSe and FeSe layers along the [001] growth direction and the [110] direction. In contrast, the ordered structure of Zn1−xFexSe grown on GaAs substrates consists of alternating ZnSe and FeSe layers along the < 111 > directions. We have also investigated the role of the misfit strain associated with the lattice mismatch between the epilayers and the substrates on the type of ordered structure.
Nucleation and Growth Model for Metal-On-Fcc(100) Metal Deposition
Authors: Bartelt M. C. , Evans J. W. 
Published: March 2011

AbstractWe present results of Monte Carlo simulations of irreversible diffusion-mediated nucleation and growth of square islands during deposition. This model mimics metal-on-fcc(100) metal epitaxy at lower temperatures. Our analysis focuses on the scaling of the island size and separation distributions, and their evolution with coverage. The depletion in the density of nearby island pairs is shown to produce a “Henzler ring” structure in the diffraction intensity profile.
Low Temperature Si Homoepitaxy: Effects of Impurities on Microstructure
Authors: Adamst D. P. , Eaglesham D. J. , Yalisove S. M. 
Published: March 2011

AbstractHydrogen is shown to influence the surface roughness during low temperature Si MBE. Small partial pressures (1 × 10-7 Torr) of deuterium, introduced during Si growth at 310°C, are sufficient to increase the surface width to ∼30 Å before breakdown of epitaxy. This work is consistent with previous studies of the dependence of epitaxial thickness on hydrogen partial pressure and supports a model in which surface roughening leads to the breakdown of epitaxy.
Competing Kinetic and Thermodynamic Processes in the Growth and Ordering of Ga0.5In0.5P
Authors: Kurtz Sarah R. , Olson J. M. , Arent D. J. , Kibbler A. E. , Bertness K. A. 
Published: March 2011

AbstractThe band gap of Ga0.5In0.5P is studied as a function of growth temperature, growth rate, and substrate misorientation. As each of these parameters is independently varied the band gap first decreases, then increases, resulting in “U” shaped curves. Each “U” shaped curve shifts if any other growth parameter is varied. The data presented here can be divided into two regions of parameter space. In the low temperature, low substrate misorientation, high growth rate region, the band gap is shown to decrease with increasing growth temperature, decreasing growth rate, and increasing substrate misorientation. In the high temperature, high substrate misorientation, low growth rate region, the opposite trends are observed. The implications of these data on the ordering mechanism are discussed.
Formation of Intrinsic Defects at MBE-Grown GaAs/AlAs Interfaces
Authors: Krispin P. , Hey R. , Kostial H. , Höricke M. 
Published: March 2011

AbstractWe report on a detailed investigation of MBE-grown isotype silicon-doped heterostructures by capacitance/voltage (C/V) technique and deep-level transient spectroscopy (DLTS). A sequence of electrically active defects is found. By depth profiling of the density of the dominant levels it is demonstrated that the corresponding defects are concentrated at the GaAs-on-AlAs (inverted) interface. By comparison with studies on irradiation-induced levels in LPE- or VPE-grown AlGaAs we conclude that the defects at the GaAs/AlAs interface are most probably linked to different charge states of the arsenic vacancy VAs and VAs−ASi pairs.
Growth Morphology of InN Thin Films by Scanning Tunneling and Atomic Force Microscopies and X-Ray Scattering
Authors: Bryden Wayne A. , Hawley Marilyn E. , Ecelberger Scott A. , Kistenmacher Thomas J. 
Published: March 2011

AbsiractThe evolution of the growth morphology of thin films of InN on (00.1) sapphire and on (00.1) sapphire prenudeated by a layer of AIN have been followed as a function of the thickness of the InN overlayer. The InN thin films and the AIN nucleation layers were deposited by reactive magnetron sputtering and first characterized by X-ray scattering, profilometry, and electrical transport. These AIN-nucleated InN films displayed heteroepitaxial grains, and high Hall mobility -even in the limit of InN overlayer on the order of 20-40Å. In parallel, InN films of varying thickness were grown directly onto (00.1) sapphire. These films showed a mixture of textured and heteroepitaxial grains, and lower Hall mobility. Atomic force and scanning tunneling microscopy studies have focussed on the morphology of the InN films with thicknesses: (a) much smaller than the AIN nucleation layer; and, (b) near the morphological transition that occurs at ∼1μm and has been attributed to the crossover from a 2D to a 3D growth mechanism. Additional correlations of X-ray structural coherence with growth mode are also examined.
Effects of Hyperthermal Carbon Subimplantation Doping on the Raman Spectra of Gaas
Authors: Fons P. , Makita Yunosuke , Kimura Shinji , Iida Tsutomu , Yamada Akimasa , Shibata Hajime , Obara Akira , Tsai Yushin , Uekusa Shin-Ichiro 
Published: March 2011

ABSTRACTThe structural effects of low-energy (30-500 eV), mass separated C12 Ion doping of GaAs simultaneous with conventional solid source MBE growth have been studied using room-temperature raman scattering, Hall-effect, transmission electron microscopy and 2K photoluminesence measurements for GaAs epitaxy temperatures of 550 ºC. Results indicate good acceptor activation without detectable residual damage is achieved for ion energies ≤ 240 eV, while at EIon = 500 eV, residual damage is present with a corresponding reduction in electrical activation. Low-energy TRIM calculations indicate that the damage is related to the increased depth distribution of vacancies and interstitials created during the higher (500 eV) implantation process which can not be annealed out at growth temperatures. Constant energy (100 eV) film growth experiments for a range of implantation currents (45 pA/cm2 - 45 nA/cm2) and growth temperatures of 550 and 550 ºC, show LO Raman peak broadening and mode hardening for currents ≥15 nA while maintaining very high C acceptor activation. This is interpreted as residual stress due to small amounts of interstitial C in the highest doped films. Both Hall mobility measurements and photoluminesence show no evidence of C dopant compensation.
Extended Damage Depth Determinations in AR- and H-Implanted Silica Glass
Authors: Arnold G.W. , Battaglin G. , Mazzoldi P. 
Published: March 2011

ABSTRACTDamage depths for Ar-implanted fused silica have been examined by Rutherford backscattering (RBS) and elastic recoil detection (ERD) ion-beam analysis. H incursion (6 at. %) from ambient atmospheres to twice TRIM values was found for damage depths which intersected the surface. H implants were used to decorate Ar damage for deeper Ar implants. The incursion of H for high-fluence implants is important for optoelectronic applications.
Dynamic Annealing and Amorphous Phase Formation in Si, GaAs and AlGaAs Under Ion Irradiation
Authors: Williams J.S. , Tan H.H. , Goldberg R.D. , Brown R.A. , Jagadish C. 
Published: March 2011

ABSTRACTIon damage processes and amorphous phase formation are compared in Si, GaAs and Alx Ga1-x As materials in the critical regime where dynamic defect annealing is strongly competing with ion damage production. It is shown that the nature of residual damage is very strongly dependent on temperature, ion dose and dose rate in this critical regime for both Si and GaAs and that the amorphous phase can be “nucleated” by high levels of extended defects. In Alx Ga1-x As, the amorphous phase is increasingly more difficult to nucleate with increasing Al concentration at LN2 temperature but can be nucleated at sufficiently high implantation doses for all Al concentrations. No dose rate effect is observed for Alx Ga1-x As. This behaviour is discussed in terms of the availability of mobile defects and bonding configurational changes during irradiation.
RBS Study of the Diffusion of Implanted Au and Pb in α-Zr
Authors: R.S. Cesar , Silva Da , Zawislak Fernando C. 
Published: March 2011

ABSTRACTThe diffusion and solubility of Au and Pb in α-Zr are measured in the temperature ranges of 773-973 K and 773-1023 K, respectively, using the Rutherford backscattering technique. Au and Pb have been implanted in samples of Zr having different amounts of Fe as impurity. The results indicate that both solutes follow a substitutional extrinsic diffusion process enhanced by the fast diffusing Fe impurity, and that the solid solubility of Au and Pb in Zr is of ≈lat% in the measured range of temperature.
Diffusion of Ion Implanted Ruthenium and Osmium IN GaAs and InP
Authors: Kuttler M. , Knecht A. , Bimberg D. , Kräutle H. 
Published: March 2011

ABSTRACTThe redistribution of the dopants Ru and Os implanted into GaAs and InP as well as the structural properties of the hosts are investigated in dependence of the annealing procedure. Results of Rutherford backscattering and secondary-ion-mass-spectroscopy experiments are presented. The RBS results of Os in GaAs annealed at 850°C indicate that an amount of about 1018 cm-3 Os is on substitutional sites. Two different diffusion processes are observed: an uphill diffusion in the amorphized region and a Fick-type diffusion in the tail of the depth profiles. The diffusion coefficients for Ru in GaAs at 850°C and Os in InP at 750°C are estimated to 4*10-14 cm2s-1 and 8*10-15 cm2s-1, respectively.
Induced Crystallization in CW Laser-Irradiated Sol-Gel Deposited Titania Films
Authors: Exarhos Gregory J. , Hess Nancy J. 
Published: March 2011

ABSTRACTIsothermal annealing of amorphous TiO2 films deposited from acidic sol-gel precursor solutions results in film densification and concomitant increase in refractive index. Subsequent heating above 300°C leads to irreversible transformation to an anatase crystalline phase. Similar phenomena occur when such amorphous films are subjected to focused cw laser irradiation. Controlled variations in laser fluence are used to density or crystallize selected regions of the film. Low fluence conditioning leads to the evolution of a subtle nanograin-size morphology, evident in AFM images, which appears to retard subsequent film crystallization when such regions are subjected to higher laser fluence. Time-resolved Raman spectroscopy has been used to characterize irradiated regions in order to follow the crystallization kinetics, assess phase homogeneity, and evaluate accompanying changes in residual film stress.
Atomic Transport by Ballistic Atomic Mixing Effect in Bilayer Structure
Authors: Chae K.H. , Choi J.M. , Jung S.M. , Song J.H. , Woo J.J. , Whang C.N. 
Published: March 2011

ABSTRACTA dynamic Monte-Carlo simulation (MCS) program, containing not only collisional mixing but also sputtering effects, has been used to elucidate the dynamic mixing processes and the atomic transport of constituents in Al-Pd bilayer systems. MCS results reveal that the preferential inward displacement of the top layer element dominates, and that there is an enhancement of the inward displacement when the heavier element is in the top layer. The inward displacement is controlled by both of an anisotropic and isotropic atomic transport. The anisotropic term is caused by the primary recoil of atoms, which has a characteristic of φ(ion dose) dependence, and the isotropic term is associated with the random cascade motion, which has a dependence. However the outward displacement is governed by only the isotropic motion, thus the inward displacement always dominates over the outward motion, which leads to a preferential displacement of top layer element to the bottom layer.
The Effects of Amorphous Layer Regrowth on Carbon Activation in GaAs and InP
Authors: Moll A.J. , Ager J.W. , Yu K.M. , Walukiewicz W. , Haller E.E. 
Published: March 2011

ABSTRACTThe effect of the Ga dose on the activation of implanted carbon in GaAs is determined. The free hole concentration is found to depend on the depth of the amorphous layer created by the Ga co-implant. Initial results on C implantation in InP indicate the behavior of C is very different in InP when compared to GaAs. The role of precipitation in reducing the activation of C in both GaAs and InP is discussed.
Binding of Copper and Nickel to Cavities in Silicon Formed by Helium Ion Implantation
Authors: Myers S.M. , Follstaedt D.M. , Bishop D.M. 
Published: March 2011

ABSTRACTCavities formed in Si by He ion implantation and annealing are shown be strong traps for Cu and Ni impurities. Experiments utilizing ion-beam analysis and transmission electron microscopy indicate that Cu is trapped at the internal surfaces of cavities up to ≈1 monolayer coverage with a binding energy of 2.2±0.2 eV relative to solution. This is greater than the heat of solution from the precipitated Cu3Si phase, determined to be 1.7 eV in agreement with earlier work. Copper at cavity-wall sites is reversibly replaced by H during heating in H2 gas, indicating the relative stability of the two surface terminations. Initial results for Ni impurities indicate that trapping at cavities is again energetically preferred to suicide formation. The saturation coverage of Ni on the internal surfaces, however, is an order of magnitude smaller for Ni than Cu, consistent with published studies of external-surface adsorption. These results suggest that cavity trapping may getter metallic impurities in Si more effectively than methods based on suicide precipitation.
Channeling Phenomena of Direct Si-Implantation to Liquid-Glass Encapsulation Czochralski GaAs Crystal Wafers Through Observation of Threshold Voltages
Authors: Saito Yasuyuki , Fukuda Katsuyoshi 
Published: March 2011

ABSTRACTThreshold voltages of Si-implanted gallium arsenide (GaAs) MESFETs depend on not only wafer crystallographic characteristics, but also MESFET fabrication processes. When the position of the orientation flat was changed to improve mechanical shock tolerance, it was found that Vth varied on the wafers due to a crystallographic orientation effect on the Si implantation. Thus, we investigated Vth distributions on wafers of several different Si implantation orientations. It was confirmed that Vth largely varies according to Si-implantation orientations.
Structure and Electrical Properties of Yttria Stabilized Zirconia by Iron Ion Implantation
Authors: Guomei Wang , Zuyuan Qu 
Published: March 2011

ABSTRACTFe ions were implanted into yttria stabilized zirconia with doses of 5×1015 -2×1017 ions/cm2 at an energy of 140 KeV. The effects of Fe-implanted zirconia and post-implantation thermal annealing on electrical properties and structure of an implanted layer were studies by electric measurement, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). It was found that the resistivity for the as-implanted sample decreased greatly with increasing ion dose, and at high dose the resistivity decreasing gradually. After annealing at 1200°C in N2 environment, the resistivity relative to that for the as-implanted sample had clearly marked decreases. Results of the XRD and XPS measurements showed that the implanted Fe ion was mainly in a charge state of Fe2+ and the sections of Fe2+ were incorporated into the ZrO2 lattice, forming a FeZrO3 compound. Finally, the conductivity mechanisms were discussed briefly.
Effects of annealing and cobalt implantation on the optical properties of βFeSi2.
Authors: Finney M S , Yang Z , Harry M A , Reeson K J , Homewood K P , Gwilliam R M , Sealy B J 
Published: March 2011

ABSTRACTIn this paper optical absorption and photoluminescence (PL) techniques are used to study the optical properties of βFeSi2 layers fabricated by Ion Beam Synthesis (IBS). The way in which the band-gap varies when a small dose of Co is added before Fe implantation is also investigated. Our results indicate that the band-gap for βFeSi2 is direct with a value of O.87eV. When a sufficiently high dose (1×1016cm-2) of Co is implanted prior to Fe we see the appearance of an additional band-gap after annealing at 1173K which we attribute to the formation of a ternary CoxFeySiz, phase. We also show that by placing the sample in a hydrogen plasma it is possible to raise the temperature at which PL occurs in βFeSi2 to ~ 200K.
Thermal Surface Treatment Using Intense, Pulsed Ion Beams
Authors: Stinnett R. W. , Buchheit R. G. , Greulich F. A. , Hills C. R. , Kilgo A. C. , Mclntyre D. C. , Greenly J. B. , Thompson M. O. , Johnston G. P. , Rej D. J. 
Published: March 2011

ABSTRACTSurface treatment experiments using intense pulsed ion beams have demonstrated new capabilities for materials surface treatment. These experiments have confirmed corrosion resistance, surface hardening, amorphous layer and nanocrystalline grain size formation, metal surface polishing, controlled melt of ceramic surfaces, surface cleaning and oxide layer removal by rapid melting and resolidification. Deposition of beam energy in a thin surface layer allows melting of the layer with relatively small energies (1-10 J/cm2) and allows rapid cooling (109-1010 K/sec) and resolidification of the melted layer by thermal diffusion into the underlying substrate. At higher intensities (≥20 J/cm2), this technology can provide rapid ablation of material from targets followed by rapid, congruent deposition of polycrystalline thin films on substrates. This technology uses high energy pulsed (40–400 ns) ion beams to directly deposit energy in the top 2–20 micrometers of the surface of materials.
Ion Beam Assisted Deposition- R&D to Production
Authors: Hirvonen James K. 
Published: March 2011

ABSTRACTIon Beam Assisted Deposition (IBAD) involves vacuum deposition processes which incorporate concurrent energetic ion bombardment and material deposition. The effects of the ions are to promote adhesion, densify the films, and to help chemically incorporate reactive ions into the coatings. Examples of IBAD studies that have progressed from R&D to production status are presented with a discussion of the technical and marketing factors influencing their commercial acceptance.
Tantalum Ion Implantation into Cu-12Nb for Electromagnetic Railgun Technology
Authors: Otooni M.A. , Brown Ian , You Xiang , Foner S. 
Published: March 2011

ABSTRACTAnalysis of fired rails from electromagnetic railgun indicates gross surface melting near the breach end of the rails. This effect is most likely caused by joule heating and arc erosion. To improve the mechanical behavior of the rail material, alloys of copper, such as Cu-0.6 Nb, has been used in the past with moderate success. More recently another alloy of copper, Cu-18 Nb, has become available. Preliminary metallurgical research in the thermomechanical properties of this latter alloy indicates it could be a candidate for application in EM gun systems. In this effort we have attempted to study the influence of ion implantation on the thermomechanical properties of Cu-12Nb alloy. In a series of experiments, Ta ions have been implanted at an energy range of 100–180 KeV and a dose of 5 × 1016 cm-2. Several analytical techniques such as Rutherford Back Scattering (RBS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), arc erosion, and microhardness measurements have been done. It has been shown that although there is an improvement in the microhardness of the implanted materials, the ion implantation saturation dose cannot exceed 5 × 1016 cm-2. Furthermore, the RBS data indicate that the implanted Ta resides mostly at a depth of about 200–300 Å from the surface. Results from the SEM analysis of unimplanted Cu-12Nb indicate the Nb has an acicular morphology and is randomly distributed. Results from microhardness measurements of the implanted materials indicate that implantation enhances the microhardness. In another experiment, such as implantation of Ta in an already TiN coated surface, we observed a similar increase in the microhardness value. We speculate that the microhardness improvement of Cu-18Nb or the Ta implanted TiN surface is due to induce compressional stresses near the lenticular (filament) Nb fibers in the Cu-18Nb composite.
The Use of Negative Ions in Ion Implantation with Tandem High Energy Accelerators
Authors: O'Connor John P. , Tokoro Nobuhiro 
Published: March 2011

ABSTRACTSince the introduction of the G1500 ion implanter, the use of tandem accelerators in production ion implantation systems has become well established. However, the beam currents which are attainable at present at low energies (< 200 keV) are suitable for only low and low-end medium dose implants. An approach to increase low energy beam currents in d.c. tandem accelerators is presented. Specifically, the use of negative ions which have been generated in the injector are transported to the end station and implanted into the wafers. In this work, beam current measurements performed using the G1500 system are presented for the typical semiconductor dopants. System changes which are necessary to accomplish implants with negative ions are discussed. A comparison of sheet resistances and uniformities measured with both positive and negative ions at the same energy and from the same G1500 system are presented. SIMS profile measurements of implants with both positive and negative ions at the same energy are also presented.
Ion Beam Synthesis of Buried COXNi1-xSi2 Layers in Silicon
Authors: Wu M.F. , De Wachter J. , Van Bavel A.-M. , Pattyn H. , Langouche G. , Vanhellemont J. , Bender H. , Temst K. , Wuyts B. , Bruynseraede Y. 
Published: March 2011

ABSTRACTHeteroepitaxial CoxNi1-xSi2 layers with good crystalline quality have been formed by ion beam synthesis. Rutherford Backscattering (RBS) - Channeling, Auger Electron Spectroscopy (AES), Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) have been used to study the buried layers. For a sample with x=0.66, we found that this ternary suicide layer contains 11% type B and 89 % type A orientation. The TEM investigation reveals that the type B component is mainly located at the interfaces with a thickness of a few monolayers. XRD studies show that the strain of the type B component is smaller than that of the type A component, and this is probably the reason for such a unique distribution of the type B component in the epilayer.
Electrical and Optical PROPERTIES OF Co ALLOYED ß-FeSi2 Formed by Ion Beam Synthesis
Authors: Panknin D. , Henrion W. , Wieser E. , Voelskow M. , Skorupa W. , Vöhse H. 
Published: March 2011

ABSTRACTBy subsequent implantation of iron and cobalt into silicon buried layers of semiconducting ß-(Fe1-xCo1-x)Si2 are formed. The band gap energy as well as the spreading resistance decrease with increasing cobalt content. The microstructure of the suicide layers is characterized by XTEM images.
Formation of CoSi2 Wires by Maskless Implantation with the Focused Ion Beam
Authors: Teichert J. , Bischoff L. , Hesse E , Panknin D. , Skorupa W. 
Published: March 2011

ABSTRACTThe maskless ion implantation with the focused ion beam as a new method for ion beam synthesis of cobalt suicide wires is presented. In order to perform the implantation a special achromatic mass separator was implemented into the ion column, liquid alloy ion sources for cobalt ions were developed and a substrate heating was built. Ion implantation was performed with 30 keV Co+ and 60 keV Co++ ions. The dose dependence for room temperature implantation and the influence of the substrate temperature were investigated.