bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidation Effects During the Formation of Buried Sb Dopant Profiles in Silicon Using Pulsed Laser Epitaxy
Authors: Carolissen Randall J. , Pretorius R. 
Published: March 2011

ABSTRACTSevere oxidation inhibited epitaxy when buried Sb profiles in single crystal silicon were formed from evaporated layers irradiated in atmosphere with a pulsed Q-switched ruby laser. Oxygen concentrations as high as 5×1017atoms/cm2 (equivalent to 105nm SiO2) were measured. However, structures prepared without the Sb layer and irradiated under identical conditions, showed no oxidation. Oxidation of Sb as a source of the measured oxygen was ruled out, while the total heating time during laser irradiation is so short (nano- to milliseconds) that normal oxidation kinetics cannot account for the amount of SiO2 measured. Irradiations in vacuum and in a helium ambient showed that the oxygen responsible for these effects is supplied from the ambient in which irradiations are carried out. Also no oxidation was observed when structures, prepared on a substrate heated to 350°C, were irradiated in atmosphere. A model to account for these oxidation effects is proposed.
Localized States in Electron-Irradiated GaAs
Authors: Kouimtzi S. D. , Melidis C. , Achtlleos C. 
Published: March 2011

ABSTRACTBand tailing produced by electron irradiation of n-type GaAs at helium temperatures is studied. It has been observed that conductance in the band tailing occurs via localized states as evidenced by the observation of a conductance having a frequency dependence of the form σ⊥ωs where ≈ 1.Sufficient degree of damage induces variable range hopping, σ ∝ exp (-b/Tl/4) in a defect band. The frequency dependence of the conductivity in this band is very weak.
Dependence of Buried CoSi2 Resistivity on ION Implantation and Annealing Conditions1
Authors: Namavar Fereydoon , Kalkhoran N. M. , Manke J. M. , Luo L. , McGinn J. T. 
Published: March 2011

ABSTRACTWe have investigated the dependence of electrical and material properties of buried CoSi2 layers on Co+ implantation and annealing conditions. The results indicated that the electrical resistivity and crystalline quality of the implanted buried CoSi2 layers depend strongly on the implantation temperature. CoSi2 layers with the lowest resistivity and best crystalline quality (Xmin as low as 3.6%) were obtained from samples implanted at 300°C-400°C. Implantation at higher temperatures (e.g., 580°C) produced cobalt disilicide layers with significantly higher electrical resistivity and a Xmin of about 10.7%.
Temperature Effects in Ion Beam Mixing of Oxide-Oxide Interfaces
Authors: Joslin D. L. , Romana L. J. , White C. W. , McHargue C. J. , Thévenard P. A. , Honon L. L. 
Published: March 2011

ABSTRACTIon beam mixing of thin oxide films, Cr2O3 and ZiO2, on sapphire substrates has been studied. The systems were chosen according to their solubilities in α-Al2O3: Cr2O3 is completely soluble, while ZrO2 is insoluble. Mixing experiments were performed on 50 nm-thick Cr2O3 and ZrO2 films deposited on αAl2O3 by radio frequency (rf) sputter deposition. The specimens were bombarded with Cr+ at an energy of 160 keV to a fluence of 4×1016 ions-cm−2. Implantations were performed at 25 and 860°C. Rutherford backscattering spectroscopy was performed to analyze any interface modifications due to the bombardment. No detectable mixing was observed in either system for irradiations performed at 25°C, but a small amount of ballistic mixing was observed in both systems at 860°C.
Optical and Infrared Spectroscopy of Laser Irradiated BI Implanted SiO2 Glasses
Authors: Magruder R. H. , Henderson D. O. , Morgan S. H. , Zuhr R. A. 
Published: March 2011

ABSTRACTOptical and infrared reflection spectra for Bi-implanted high-purity silica are reported as a function of dose and 5eV laser irradiation. The extinction coefficient per ion and the reflectance spectra are dose dependent. Subsequent effects of laser irradiation are dependent upon Bi content and total number of laser pulses. Changes reported are attributed to two photothermal processes. One involving diffusion and desorption of Bi ions and annealing of defects, while the second is dominated by annealing.
Collisional Energy Deposition Threshold for Extended Damage Depths in Ion-Implanted Silicates
Authors: Arnold G. W. , Battaglin G. , Boscolo-Boscoletto A. , Caccavalle F. , De Marchi G. , Mazzoldi P. 
Published: March 2011

ABSTRACTMany properties of implanted fused silica (e.g., surface stress, hardness) exhibit maximum implantation-induced changes for collisional energy deposition values of ∼1020 keV/cm3. We have observed a second critical energy deposition threshold value of about 1022 keV/cm3 in stress and hardness measurements as well as in many other experiments on silicate glasses (leaching, alkali depletion, etching rate, gaseous implant redistribution). The latter show evidence for damage depths exceeding TRIM ranges by about a factor of 2. For crystalline quartz, a similar threshold value value has been found for extended damage depths (greater than TRIM) for 250 kev ions (H-Au) as measured by RBS and interference fringes. This phenomenon at high damage deposition energy may involve the large stress gradients between damaged and undamaged regions and the much increased diffusion coefficient for defect transport.
Plastic Deformation and Micro-Fracture in SiO2 Induced by Electron Beam Irradiation
Authors: Ajayan P. M. , Iijima Sumio 
Published: March 2011

ABSTRACTWe present here experimental results using transmission electron microscopy (TEM) and real time video recordings, of the many dynamic structural instabilities in amorphous silica structures during intense electron beam irradiation. It is observed that while the silica layers on oxidized silicon particles sinter when irradiated uniformly, they undergo necking and extensive plastic deformation when the beam is focused in the neck regions. Extremely thin silica fibers (less than five nanometers in diameter and microns in length) can be produced by the deformation of such necks between particles. The thin fibers and the sharp tips developed from the failure of such structures are seen to spheroidize and blunt when exposed to the electron beam. The instabilities are thought to arise from irradiation induced charging of the insulator surface which expands to reduce the density of accumulated surface charges.
Pulsed Laser Annealing of Buried Damage in Ion Implanted Diamond
Authors: Prawer Steven , Jamieson D. N. , Dooley S. P. , Spizzirri P. , Ghiggino K. P. , Kalish R. 
Published: March 2011

ABSTRACTDamaged layers, buried underneath the surface of type IIa diamond slabs by 2.8 MeV C+ ion implantation have been subjected to irradiation with 14 ns pulses from a focused Nd-Glass laser. At high powers, ablation of the implanted surface was observed. However, the correct choice of laser power and wavelength results in annealing of the implanted layer without any disruption to the surface morphology. Annealing was confirmed by optical measurements showing a decrease in the GR-1 absorption band, and by channelled Rutherford Backscattering Spectroscopy on the small 10μm diameter laser irradiated spots. The results suggest that an undamaged diamond cap can be utilized to promote damage annealing of diamond by pulsed laser beams, for which the annealing in other materials has been shown to proceed via the melt. The surface cap is believed to aid in the production of extremely high internal pressures in the damaged layer during the laser pulse which prevents graphitization and promotes diamond regrowth.
Hardening in AlN Induced by Point Defects
Authors: Suematsu H. , Mitchell T. E. , Iseki T. , Yano T. 
Published: March 2011

ABSTRACTPressureless-sintered AlN was neutron irradiated and the hardness change was examined by Vickers indentation. The hardness was increased by irradiation. When the samples were annealed at high temperature, the hardness gradually decreased. Length was also found to increase and to change in the same way as the hardness. A considerable density of dislocation loops still remained, even after the hardness completely recovered to the value of the unirradiated sample. Thus, it is concluded that the hardening in AlN is caused by isolated point defects and small clusters of point defects, rather than by dislocation loops.Hardness was found to increase in proportion to the length change. If the length change is assumed to be proportional to the point defect density, then the curve could be fitted qualitatively to that predicted by models of solution hardening in metals. Furthermore, the curves for three samples irradiated at different temperatures and fluences are identical. There should be different kinds of defect clusters in samples irradiated at different conditions, e.g, the fraction of single point defects is the highest in the sample irradiated at the lowest temperature. Thus, hardening is insensitive to the kind of defects remaining in the sample and is influenced only by those which contribute to length change.
Phase Transformations by Yttrium Implantation into Pure Aluminum
Authors: Ning X. G. , Ji C. Z. , Ye H. Q. 
Published: March 2011

ABSTRACTPhase transformations by yttrium implantation into pure aluminum using 60kV ions and 3×1017 ions/cm2 dose have been studied by transmission electron microscopy (TEM). YAl3(12R) particles with an average size of 0.3μm were formed in the modified aluminum surface, which transformed into YFe3·5Alx (predominantly) and YAl3(8H) phase particles with 2 μm average diameter after being annealed at 600°C for one hour. The Fe ions were introduced by ion sputtering from the iron screws of the specimen holder, a previously unnoticed effect during heavy metal ion implantation for surface modification of materials. Electron diffraction experiments indicated that the YFe3·5Alx was a new phase and belongs to the orthorhombic system with a C-face-centered lattice (a=c=0.887nm, b=1.024nm). The reciprocal lattice of the YFe3·5Alx phase is related to that of the YFe4Al8 magnetic phase. The microstructure of the modified aluminum surface was also investigated by high-resolution TEM.
RBS/Channeling Diffusion Studies of High Energy Au Implanted Mg Single Crystals
Authors: Da Selva R. C. , Da Silva M. F. , Thomé L. , Melo A. A. , Soares J. C. 
Published: March 2011

ABSTRACTRBS/channeling analyses of high energy Au implantation into Mg are presented. The diffusion behaviour of Au was studied and the occurrence of essentially two distinct regimes were observed: the segregation regime at lower temperatures correlated with the damage introduced by the high energy implantation and the higher temperature regime as a normal thermally activated process of back-diffusion.
Analysis of Experiments in Helium Microbeam Mixing
Authors: Davis John B. , Benenson R. E. , Peak David 
Published: March 2011

ABSTRACTWe have continued to investigate ion-beam mixing in bilay-er targets irradiated by 2-MeV He+ microbeams at room temperature. Although we have previously reported a linear dependence of interface width on dose for Cu/Al targets 1, more extensive results have not supported this conclusion, within statistical uncertainty, it appears that the interface width in Cu/Al (1) is proportional to the square root of dose, at constant dose rate, (2) is larger in Al than in Cu, for the same dose, (3) is proportional to the 1/4 power of dose rate, and (4) is absent at liquid nitrogen temperature. Calculations of the expected interface growth rate from a radiation-enhanced diffusion model have provided order-of-magnitude agreement with observed rates. Additionally, intermixing of Cu and Al outside the damaged area may indicate significant transverse diffusion of vacancies.
Radiation Enhanced Tracer Diffusion in Intermetallic Alloys
Authors: Lee Y. S. , Averback R. S. , Flynn C. P. 
Published: March 2011

ABSTRACTRadiation enhanced diffusion in the intermetallic alloy Cu3Au was measured directly for the first time. Ni and Pd tracer impurities were used to probe the diffusion of atoms occupying Cu and Au sublattice site's, respectively. Measurements were performed temperatures both above and below the ordering temperature, of TC =390°C The ability to grow high quality Cu3Au films by MBE with buried marker layers in the form of either (Cu2Ni)Au or Cu3(AuPd), made these measurements possible. Under irradiation with 0.75MeV Ar+ ions, the diffusion of Ni is approximately equal to that of Pd above Tc, but smaller below Tc. In the absence of irradiation, the thermal diffusion coefficients reveal a similar trend. Activation energies for RED for the two species are similar both above and below Tc whereas, in absence of irradiation, the activation enthalpies below Tc are different. These results are interpreted on the basis of lattice order.
The Effect of Ion Irradiation on Inert Gas Bubble Mobility
Authors: Alexander Dale E. , Birtcher R. C. 
Published: March 2011

ABSTRACTThe effect of Al ion irradiation on the mobility of Xe gas bubbles in Al thin films was investigated. Transmission electron microscopy was used to determine bubble diffusivities in films irradiated and/or annealed at 673K, 723K and 773K. Irradiation increased bubble diffusivity by a factor of 2–9 over that due to thermal annealing alone. The Arrehnius behavior and dose rate dependence of bubble diffusivity are consistent with a radiation enhanced diffusion phenomenon affecting a volume diffusion mechanism of bubble transport.
Structure Transformations of the Decagonal and Icosahedral Phases in Quaternary Alloys.
Authors: Perez R. , Reyes-Gasga J. , Jose-Yacaman M. 
Published: March 2011

ABSTRACTAn investigation of the phase transformations experienced by the decagonal and icosahedral phases in two different quaternary -alloys is carried out. The transformation in the decagonal phase of Al-Cu-Co-Si alloy is induced by the electron radiation in a transmission electron microscope. However, in the icosahedral phase of Al-Cu-Co-Fe alloy this transformation is induced by annealing. Electron diffraction patterns obtained from both phases suggest that the deformation mechanism involved in these kind of transitions is related with twinning
Interdiffusion and Grain-Boundary Migration in Au/Cu Bilayers During Ion-Irradiation
Authors: Alexander Dale E. , Rehn L. E. , Baldo Peter M. 
Published: March 2011

ABSTRACTIon irradiation and annealing experiments have been conducted on Au/Cu bilayer films to evaluate the effect of irradiation on diffusion-induced grain boundary migration (DIGM). The Au films were prepared with a large-grained microstructure with grain boundaries perpendicular to the film surface and extending through the film thickness. Irradiations were conducted with 1.5 MeV Kr at 228°C. Rutherford backscattering spectrometry of the samples revealed that interdiffusion was substantially enhanced in the irradiated area relative to the unirradiated area. Both irradiated and annealed-only areas were characterized by a nearly uniform composition of 14 at.% and 7 at.% Cu respectively through the entire thickness of the underlying Au film. Small probe X-ray energy dispersive spectroscopy showed significant lateral compositional homogeneities in both irradiated and annealed areas. These two results are consistent with previous observations of DIGM in the Au/Cu system, suggesting that this previously unexamined interdiffusion mechanism contributes to ion beam mixing.
Ion Induced Grain Growth in Pd
Authors: Lilienfeld D. A. , Bøorgesen P. , Meyer P. 
Published: March 2011

ABSTRACTIon irradiation induced grain growth size distributions in Pd are examined at low temperatures. Two features are observed: 1) A majority of the grains saturate in size. 2) Some grains achieve sizes much larger than the average grain size and continue to grow with ion dose. However, by careful choice of ion mass and ion dose, it is possible to produce a sample possessing a monomodal grain size. This process will have applications in producing thin films of nanocrystalline materials.
Stress and Phase Changes in Ion-Assisted Evaporation of Thin Tantalum Films
Authors: Roy R. A. , Catania Philip 
Published: March 2011

ABSTRACTIon-assisted evaporation was used to study the stress and phase changes in thin Ta films. Using a series of ion energies from 63 to 500 eV, the stress in 100 nm thick films was changed from tensile to compressive by increasing the argon ion flux incident on the growing films. The resulting films were characterized primarily by x-ray diffraction and electrical resistivity measurements, as well as RBS. The resistivity in all sets of films shows a large decrease with increasing argon ion flux. The x-ray diffraction results are somewhat more complex, but suggest that increasing ion flux does change the amount of alpha phase present.
Epitaxy and Chemical Reactions During Thin Film Formation from Low Energy Ions New Kinetic Pathways, New Phases and New Properties
Authors: Herbots Nicole , Hellman O. C. , Vancauwenberghe O. 
Published: March 2011

ABSTRACTThree important effects of low energy direct Ion Beam Deposition (IBD) are the athermal incorporation of material into a substrate, the enhancement of atomic mobility in the subsurface, and the modification of growth kinetics it creates. All lead to a significant lowering of the temperature necessary to induce epitaxial growth and chemical reactions. The fundamental understanding and new applications of low temperature kinetics induced by low energy ions in thin film growth and surface processing of semiconductors are reviewed. It is shown that the mechanism of IBD growth can be understood and computed quantitatively using a simple model including ion induced defect generation and sputtering, elastic recombination, thermal diffusion, chemical reactivity, and desorption. The energy, temperature and dose dependence of growth rate, epitaxy, and chemical reaction during IBD is found to be controlled by the net recombination rate of interstitials at the surface in the case of epitaxy and unreacted films, and by the balance between ion beam decomposition and phase formation induced by ion beam generated defects in the case of compound thin films. Recent systematic experiments on the formation of oxides and nitrides on Si, Ge/Si(100), heteroepitaxial SixGe1−x/Si(100) and GaAs(lOO) illustrate applications of this mechanism using IBD in the form of Ion Beam Nitridation (IBN), Ion Beam Oxidation (IBO) and Combined Ion and Molecular beam Deposition (CIMD). It is shown that these techniques enable (1) the formation of conventional phases in conditions never used before, (2) the control and creation of properties via new degrees of freedom such as ion energy and lowered substrate temperatures, and (3) the formation of new metastable heterostructures that cannot be grown by pure thermal means.
Low Temperature Silicon Epitaxial Growth by Plasma Enhanced Chemical Vapor Deposition From SiH4/He/H2
Authors: Lin Yung-Jen , Shieh Ming-Deng , Lee Chiapying , Yew Tri-Rung 
Published: March 2011

ABSTRACTSilicon epitaxial growth on silicon wafers were investigated by using plasma enhanced chemical vapor deposition from SiH4/He/H2. The epitaxial layers were growm at temperatures of 350°C or lower. The base pressure of the chamber was greater than 2 × 10−5 Torr. Prior to epitaxial growth, the wafer was in-situ cleaned by H2 baking for 30 min. The epi/substrate interface and epitaxial layers were observed by cross-sectional transmission electron microscopy (XTEM). Finally, the influence of the ex-situ and in-situ cleaning processes on the qualities of the interface and epitaxial layers was discussed in detail.
Growth And High Resolution Tem Characterization of GexSi1−x/Si Hetero-Structures by Remote Plasma-Enhanced Chemical Vapor Deposition
Authors: Qian R. , Chung I. , Kinosky D. , Hsu T. , Irby J. , Mahajan A. , Thomas S. , Banerjee S. , Tasch A. 
Published: March 2011

ABSTRACTRemote Plasma-enhanced Chemical Vapor Deposition (RPCVD) has been used to grow GexSi1−x/Si heteroepitaxial thin films at low temperatures (∼450°C). In situ RHEED has been used to confirm that smooth, single crystal heteroepitaxial films can be grown by RPCVD. Plan-view and cross-sectional TEM have been employed to study the microstructure of the heteroepitaxial films. Lattice imaging high resolution TEM (HRTEM) has shown perfect epitaxial lattice alignment at the heterojunction interfaces. GexSi1−x/Si films which exceed their CLT's appreciably show dense Moiré fringes under plan-view TEM. The spacings between the fringes have been used to estimate the relaxed lattice constants. In addition to the inhomogeneous strain observed in-XTEM, Selected Area electron Diffraction (SAD) analysis of the interfaces displays two split patterns. The spacings between the diffraction spots have been used to calculate the lattice constants in the epitaxial films in different crystal directions, which agree very well with the prediction by Vegard's law as well as the estimate from plan-view TEM analysis. HRTEM analysis also reveals the crystallographic nature of the interfacial misfit dislocations in the relaxed films.
Growth Mechanism and Film Properties in Pulsed Laser-Plasma Deposition
Authors: Metev S. , Meteva K. 
Published: March 2011

ABSTRACTIn the paper the results of a theoretical investigation of the growth process of laser-plasma deposited thin films are discussed. A kinetic approach has been used to establish direct relation between experimental conditions (laser flux density, substrate temperature) and film properties (thickness, structure). The results of some experimental investigations of the deposition process are presented confirming the general conclusions of the developed theoretical model.
Synthesis and Characterization of PbO Films Grown by Pulsed Laser Deposition.
Authors: Zabinski J. S. , Donley M. S. , Dyhouse V. J. , Moore R. , McDevitt N. T. 
Published: March 2011

ABSTRACTLead monoxide (PbO) is a potential solid lubricant for use at elevated temperatures in oxidizing environments. The objective of this research was to grow thin films of PbO by Pulsed Laser Deposition (PLD). Film stoichiometry, crystallinity, and chemistry were adjusted by varying substrate temperature and O2 partial pressure during deposition and the effects of changes in film properties on friction coefficients and wear lives were investigated. Chemistry and crystallinity were evaluated using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and glancing angle X-ray diffraction (XRD). Friction coefficients and wear lives were measured in dry nitrogen and at room temperature using a ball-on-flat tribometer. Films deposited at room temperature retained the crystal structure of the target material, but were oxygen deficient. The O/Pb ratio was increased by raising the O2 partial pressure and by increasing the substrate temperature during deposition; the crystal structure and orientation changed with stoichiometry. Friction coefficients ranged from 0.20 – 0.45 and the wear lives were typically less than those obtained from MoS2 films.