bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amorphous Phase Formation and Recrystallization in Ion-Implanted Silicides
Authors: Hewett C.A. , Suni I. , Lau S.S. , Hung L.S. , Scott D.M. 
Published: March 2011

ABSTRACTIon implantation induced phase transformations and recrystallization during post-annealing in CoSi2, CrSi2, and Pd2Si are studied. All three silicides are found to reorder at about 1/3 the melting point of the silicide. We speculate that ion-implanted silicides recrystallize by the same mechanism and that amorphous phases produced by implantation are unstable rather than metastable.
High Current Density Implantation and Ion Beam Annealing in Si
Authors: Holland O. W. , Narayan J. 
Published: March 2011

ABSTRACTAnnealing of amorphous layers in Si by high flux, selfion irradiation will be discussed. The mechanism for the lattice recovery is presented and related to the structure of the residual damage. It will be shown that highly supersaturated, alloyed regions, free from extended defects, result from the annealing process.
Formation of Oxide Layers by High Dose Implantation into Silicon
Authors: Gill S.S. , Wilson I. H. 
Published: March 2011

ABSTRACTSingle crystal silicon was implanted with 80, 120, 160 and 240 keV oxygen ions. Rutherford backscattering (RBS) analysis was used to obtain the implanted oxygen profile and the oxygen to silicon ratio in the implanted layer for doses in the range 1016 to 1.5 × 1018 O2+ cm−2 for room temperature implants. The depth and the thickness of the buried oxide layer has been measured as a function of implantation energy and oxygen dose. Chemical formation of stoichiometric SiO2 was confirmed by infra-red (IR) spectroscopy. Both RBS and IR indicate that once a surface oxide layer is formed for very high dose levels, the layer thickness decreases with increasing implanted dose beyond a critical dose level.
Characterization of Ion Implanted Silicon by Spectroscopic Ellipsometry and Cross Section Transmission Electron Microscopy
Authors: Mcmarr P. J. , Vedam K. , Narayan J. 
Published: March 2011

ABSTRACTThis paper deals with the application of spectroscopic ellipsometry (SE) and cross-section transmission electron microscopy (XTEM), to the characterization of damaged surface layers in ion implanted Si single crystal. Si samples of 2–6Ω·cm resistivity and <100> orientation were implanted with 28Si+ ions in the dose range of 1.0 × 1016–1.5 × 1016 ions/cm2 using ion energies of 100 and 200 keV. Ion current densities were varied from 6 to 200 μA/cm2. Depth profiles of the implanted samples were evaluated from the spectroscopic ellipsometry data. These calculated profiles were compared with the TEM micrographs of the cross sections of the samples. Excellent agreement is obtained between the two characterization techniques. The characteristics of the depth profiles of the samples, as established by the two techniques, is shown to be the result of annealing occuring during implantation.
Ion Implantation Damage in CdS Crystals Using RBS/Channeling and Tem
Authors: Parikh N.R. , Thompson D.A. , Burkova R. , Raghunathan V.S. 
Published: March 2011

ABSTRACTImplantation damage in single crystal of CdS produced by 60 keV Bi+ and 45 keV Ne+ at 50 K and at 300 K has been studied. Measurements of Cd disorder and dechanneling behaviour have been made by means of RBS/channeling for He ions ranging in incident energy from 1.0 to 2.8 MeV either along <0001> or <1120> axial channeling directions. The amount of disorder measured were two orders of magnitude lower than the calculated Cd disorder. Damage when analysed along the <0001> axis is larger than when analysed along the <1120> axis.Xmim values for the implanted crystals decreases as the EO increases, when analysed along <0001> direction. TEM observations of Bi implanted samples show that the dislocation loops of b = 1/3 <1120> are produced. Attempts have been made to correlate the RBS/channeling results with the defect strictures observed in microscopy.
A Channeling Study on Mg Implanted InSb Single Crystals
Authors: Alberts H.W. 
Published: March 2011

ABSTRACTProton and α-particle channeling were used to study the radiation damage caused by the implantation of 160 keV Mg ions in InSb. The implantations took place at various substrate temperatures ranging from room temperature to temperatures just below the melting point and doses ranging from 5.1013 to 1.1016 Mg+ cm−2. The isochronal annealing of the room temperature implanted crystals started at 200°C and damage could not be completely removed even at temperatures just below the melting point. For crystals implanted at elevated substrate temperatures no annealing effects during implantation occured up to 400°C. Above 400°C a sharp reduction of damage indicates that the rate of formation of more complex defect configurations during the implantation process becomes smaller than the annihilation rate of the vacancy-interstitial pairs. A non-linear dependence exists between the degree of radiation damage in the InSb lattice and the implanted dose.
A Comparative Study of Near-Surface Effects Due to Very High Fluence H+ Implantation In Single Crystal FZ, CZ, and Web SI
Authors: Choyke W.J. , Irwin R.B. , Mcgruer J.N. , Townsend J.R. , Doyle N.J. , Hall B.O. , Spitznagel J.A. , Wood S. 
Published: March 2011

ABSTRACTCrystals of float-zone, Czochralski, and Web Si having widely differing oxygen concentrations were imrplanted at 300°K with large fluences of hydrogen. Experiments using RBS/channeling, profilometry and microscopy are reported. For room temperature implants the step-height h, the distribution of displaced atoms ND(x) and the total number of displaced atoms/cm2 (aD) are all essentially independent of the oxygen convent of the Si.
Damage Distribution Studies in Proton-Implanted GaAs
Authors: Jenkinson H. A. , O'Tooni M. , Zavada J. M. , Haar T. J. , Larson D. C. 
Published: March 2011

ABSTRACTSamples of n+-GaAs implanted with 300 keV protons have been examined using high resolution electron microscopy, capacitance-voltage profilometry, and infrared reflectance. In contrast to previously reported results, electron microscopic examination of the as-implanted samples revealed the presence of dislocation loops and/or precipitates both near the wafer surface and at the bottom of the implanted layer. These results are corroborated by electrical and optical measurements.
Behavior of Implanted α-Al2O3 in an Oxidizing Annealing Environment
Authors: Farlow G. C. , White C. W. , Mchargue C. J. , Appleton B. R. 
Published: March 2011

ABSTRACTThe transition metal ions Fe, Mn, Ni, Ti, and Cr as well as the group III-A ion Ga were implanted in a random direction close to the c-axis of α-Al2O3 single crystals. These were subsequently annealed in flowing oxygen at temperatures between 600 and 1500°C. The impurity and damage distributions were determined by He backscattering and channeling techniques. The normally trivalent ions, Fe, Ga, and Cr show strong tendency to become incorporated into substitutional sites, whereas the normally divalent ions, Cu and Mn show no such tendency, even at high temperatures. Most of the impurities tend to move toward the surface with only Fe, Ga, and Cr showing tendency towards bulk diffusion. In all cases the Al sublattice recovers at lower temperatures than the oxygen sublattice.
Implantation-Induced Conductivity of Polymers
Authors: Wasserman B. , Braunstein G. , Dresselhaus M.S. , Wnek G.E. 
Published: March 2011

ABSTRACTIon implantation causes an increase by ~14 orders of magnitude in the electricalconductivity of normally insulating polymers such as polyacrylonitrile (PAN), poly(2,6 dimethyl phenylene-oxide) (PPO), and poly (pphenylene sulfide) (PPS), after ion implantation with Br at fluences of 3 × 1015 ions/cm2. The temperature dependence of the dc conductivity was measured in the range 23 〈 T 〈 293 K and results show an exponential law σ ~ exp(−To/T)a) for PAN, PPO and PPS with α =1/2, suggesting a one-dimensional hopping mechanism. The temperature dependence of the thermoelectric power (TEP) identifies the sign of the dominant carrier type. The TEP exhibits linear metallic behavior, with small magnitudes (~3μV/K), and shows Br implantation to yield p-type material in PPS and n-type material in PAN with extremely low values of mobility (〈 10−3 cm2/V sec) and correspondingly very high values of the carrier concentration estimated to be 5 × 1022 cm-3. Results are also reported for the frequency dependence of the AC conductivity and of similarly implanted PPS and PAN samples.
Comparison of Conductivity Produced in Polymers and Carbon Films by Pyrolysis and High Energy Ion Irradiation
Authors: Venkatesan T. , Dynes R. C. , Wilkens B. , White A. E. , Gibson J. M. , Hamm R. 
Published: March 2011

ABSTRACTThe electrical properties of pyrolyzed polymers have been studied recently.1,2 It has been shown that organic, polymeric3 and non-polymeric4 films can be made conductive (ρ ~ 10−3Ωcm) by ion beam irradiation. Common to all of the films was the presence of carbon as a constituent element and both pyrolysis and ion beam irradiation3 was shown to increase the relative carbon content of the films. The ion beam irradiated organic films 3,4 exhibited a temperature dependence of their resistivity of the form ρ(T) = ρ∞e−(TЛ)*, where ρ is the ion-induced resistivity, ρ∞ and T0 are constants and T is the temperature. At very high doses of irradiation (1017cm−2Ar+@ 2MeV) the film resistivity was temperature independent. Very similar transport properties were observed in the pyrolyzed polymers1 as well, though the lowest resistivities achieved were higher than the resistivity values observed in the ion irradiated3 polymer films. In both the pyrolysis and ion-irradiation experiments the temperature dependence has been explained by a model due to Sheng and Abeles,5 which involves charge transport by hopping between conducting islands embedded in an insulating matrix. Such striking similarities between two distinctly different modes of energy deposition in the films, prompted us to compare the effects of pyrolysis and ion irradiation in different carbon containing films. We compared both a polymer (HPR-204°) and a film of electron beam evaporated carbon film. While in the former case one would observe chemical degradation as well as structural modification, by studying pure carbon films the physical nature of the processes could be clarified. We report metallic carrier densities in both films and evidence for significant structural rearrangement. We conclude that pyrolysis and ion beam irradiation have similar effects on both polymer and carbon films.
Channeling Studies of Thermal Regrowth in Ion Damaged Graphite
Authors: Venkatesan T. , Elman B. S. , Braunstein G. , Dresselhaus M. S. , Dresselhaus G. 
Published: March 2011

ABSTRACTThe crystallization of disordered surface layers on highly oriented pyrolytic graphite (HOPG) have been studied by Rutherford backscattering spectrometry (RBS) and channeling techniques. Disordered layers (~1000–3000Å thick) are produced on the surface of HOPG by the implantation of various ions. The disordered layers are regrown by thermal annealing of the samples in an inert environment. Isochronal anneals reveal two distinct regrowth processes: one, a rapid process of low activation energy (Ea ~ 0.15 eV) which is observed primarily in regions where the disorder is sufficient to prevent the channeling of the ions but insufficient to totally destroy the graphitic structure. This low activation energy may indicate annealing of the damage by migration of interstitials where the interstitials are the knock-on carbon atoms produced by the primary ions. A regrowth process with higher activation energy (Ea ~ 2.0 eV) occurs primarily in regions where the disorder is close to the saturation-disorder produced by ion implantation. Both the regrowth processes are epitaxial in nature and the epitaxial nature of the process may explain the much lower activation energy for 3D AB stacking as measured in ion implanted graphite when compared with results on the bulk graphitization of pyrocarbons.
High Temperature Implantation in Graphite
Authors: Braunstein G. , Elman B.S. , Dresselhaus M.S. , Dresselhaus G. , Venkatesan T. 
Published: March 2011

ABSTRACTIn previous studies it was found that when highly oriented pyrolytic graphite (HOPG) is implanted at room temperature, the damage caused by the implantation could be completely annealed by heating the sample to temperatures higher than ∼ 2500°C. However at these high temperatures, the implanted species was found to diffuse out of the sample, as evidenced by the disappearance of the impurity peak in the Rutherford backscattering (RBS) spectrum. If, on the other hand, the HOPG crystal was held at a high temperature (≥ 600°C) during the implantation, partial annealing could be observed. The present work further shows that it is possible to anneal the radiation damage and simultaneously to retain the implants in the graphite lattice by means of high temperature implantation (Ti ≥ 450°C) followed by annealing at 2300°C.
Transport Properties and Electron Microscopy Studies of Ion Implanted Graphite
Authors: Chieu T.C. , Elman B.S. , Salamanca-Riba L. , Endo M. , Dresselhaus G. 
Published: March 2011

ABSTRACTGraphite fibers with high structural perfection and small diameters (∼1 μm) provide a sensitive medium to study the effect of ion implantation on the transport properties of graphite and to observe the defect structure associated with the implantation process. Graphite fibers prepared from the thermal decomposition of benzene and subsequent heat treatment to high temperatures (∼2900°C) have been shown to achieve the high structural perfection necessary to carry out such experiments. Implantation-induced changes in the fiber resistivity are reported and are found to be larger at low temperature, as expected on the basis of residual resistance arguments. Using the lattice fringe imaging technique of high resolution electron microscopy, the implantation-induced defect structure can be observed directly. The results show local expansion of the interlayer graphite planes, with an interlayer separation ranging up to 3.9 Å in the implanted region, compared with ∼3.4 Å for the well-ordered layers beyond the ion penetration depth.
Dynamic Recoil Mixing for the Production of Silicon Nitride Films
Authors: Kheyrandish H. , Colligon J.S. , Hill A.E. 
Published: March 2011

ABSTRACTIn Dynamic Recoil Mixing (DRM) a film of constant thickness is sputtered on to a substrate by using a broad low energy (lkeV) ion beam and is subsequently bombarded by a high energy (10 key) ion beam. During the bombardment process a dynamic balance is maintained between the backsputtering and the deposition of the film, thus providing an ‘unlimited’ source of the dopant material. In this way very high surface dopant concentrations may be achieved which otherwise cannot be reached by more conventional ion beam mixing techniques. Furthermore, by choosing reactive ion species, films of novel chemical compositions may be produced. This technique has been employed to produce silicon nitride films on polished commercial mild steel samples. Measurements of knoop hardness of these films indicate an increase of over 200% whilst the wear and friction properties have shown considerable improvement. Conventionally sputtered silicon films of similar thickness, recoil mixed silicon using argon, or implantation of 10 keV argon and nitrogen to similar doses, indicate only a modest change in tribological characteristic compared to the reactive mixed films.
Structure of Al-N Films Deposited by a Quantitative Dual Ion Beam Process
Authors: Hentzell H.T.G. , Harper J.M.E. , Cuomo J.J. 
Published: March 2011

ABSTRACTWe describe the structure of Al-N films deposited with N/Al ratios varying from 0 to 1. A dual ion beam system supplies the Al flux by inert ion sputtering, and the N flux by low energy (100–500 eV) N2+ ion bombardment of the growing film. For N/Al < 1, a cermet structure forms with large Al grains mixed with AlN. Above the composition N/Al = 1, excess N is rejected from the AlN. The AlN films show a pronounced change in preferred orientation from c-axis perpendicular to the film surface, to c-axis parallel to the film surface with increasing N2+ energy
Carrier Lifetime Reduction by Ion Implantation into Silicon
Authors: Mdgro-Campero A. , Love R.P. 
Published: March 2011

ABSTRACTIon implantation is emerging as a versatile tool for the control of carrier lifetime in silicon. We present results on the use of argon and proton implantations to reduce lifetime. Particle energies used imply submicron penetration depths into the silicon. We find that within the first micrometer from the surface, the generation lifetime can be reduced by several orders of magnitude, and varies inversely with dose. A change in doping concentration was found only at the highest dose used (1014 cm−2). Effects of the implantations on surface generation velocity and oxide charges were also studied.
Effects of Ion Implantation on the Rolling Contact Fatigue of 440C Stainless Steel
Authors: Kustas F. M. , Misra M. S. , Sioshansi P. 
Published: March 2011

ABSTRACTCylindrical 440C stainless steel specimens implanted with N and Ti were examined for their fatigue resistance and wear behavior by rolling contact fatigue (RCF) testing. The results obtained from RCF testing showed a 40% increase in the B-10 fatigue lifetime for N implanted and a 17% increase for Ti implanted 440C specimens compared to baseline, unimplanted 440C. Quantitative surface analysis by Auger Electron Spectroscopy (AES) was performed to determine the effects of process parameter optimization and ion beam masking on the elemental concentration profiles.
Dose Dependence of Ion Beam Mixing of Au on Amorphous and Single Crystalline Si and Ge
Authors: Poker D. B. , Holland O. W. , Appleton B. R. 
Published: March 2011

ABSTRACTThe rate of ion induced mixing of 700 Å Au layers vapor deposited on amorphous and single crystalline Si substrates held at room temperature was measured as a function of dose using 300 key Si, 350 keV Ar, and 525 keV Kr ion beams.Mixing profiles were measured at various fluences by Rutherford backscattering techniques and were found to be consistent with mixed layers whose thicknesses increased with ion dose. Mixing compositions, which were stoichiometric over the entire mixed region at Au-28.5 at.% Si, were found to be independent of ion species or implant fluence. For all ion species the dose dependence of mixing was closer to linear than the square root power law reported previously [1]. In addition, the mixing rate for Au on single crystalline substrates was significantly higher than Au n substrates amorphised by Si (self-ion) implantation at liquid nitrogen temperature. No difference was found between the mixing rates when the amorphous substrates were prepared by room temperature implantation. Preliminary results indicate similar behavior for the Au/Ge couple.
Applications of Ion-Implanted Covalent Polymers
Authors: Weber David C. , Bernett Marianne K. , Ravner Harold 
Published: March 2011

ABSTRACTMaterials presently used for packaging precision instrument bearings contain minor amounts of antistatic agents, shown earlier to be potential contaminants to both bearing surfaces and lubricants. One method to eliminate the antistatic additives is to use electroactive polymers. The materials with the most promise for this application are the F ion implanted polyacetylene and polyparaphenylene. The characteristics and behavior of the polymers will be presented.
Energy Dependence of Compound Growth in Au-Al and Cu-Al Bilayer Systems During Ion Beam Mixing
Authors: Campisano S.U. , Techang Chu , Cannavo ' S. , Rimini E. 
Published: March 2011

ABSTRACTThe kineticsof phase formation and growth in Au-Al and Cu-Al thin film bilayers under ion beam bombardment was investigated in detail for the dependence on the beam energy. The experimental data can be interpreted within the radiation enhanced diffusion description, taking into proper account the target configuration, the growth of a new phase and the deposited energy density distribution.
Synthesis, Structure, and Characterization of La1−xBax (0 ≤ x ≤ 1)
Authors: Sunstrom Joseph E. , Kauzlarich Susan M. 
Published: March 2011

ABSTRACTThe compounds La1−xBaxTiO3 (0 ≤ × ≤ 1) have been prepared by arc melting stoichiometric amounts of LaTiO3 and BaTiO3. Single phase samples can be made for the entire stoichiometry range. The polycrystalline samples have been characterized by thermal gravimetric analysis, X-ray powder diffraction, and temperature dependent magnetic susceptibility. This series of compounds has been studied as a possible candidate for an early transition metal superconductor.
New Group 2 Compounds Useful for Preparation of thin films of Electronic Ceramics
Authors: Rees William S. , Dippel Kerstin A. , Carris Michael W. , Caballero Celia R. , Moreno Debra A. , Hesse Werner 
Published: March 2011

ABSTRACTWe have prepared examples of several new classes of group 2 compounds, including ether- and amine-substituted metallocenes, inter- and intra-molecular Lewis base stabilized bis(β-diketonates), and clam-shell oligioether bis(alkoxides), and investigated their use as potential sources in the preparation of ceramic materials from molecular precursors. Examinations have included vapor pressure measurements, hydrolytic, oxidative, thermal and photolytic stability, vapor phase, solution and solid state structures, and evaluation for potential CVD growth of thin films of electronic ceramics. Results to date indicate that intramolecular stabilization is more advantageous than intermolecular stabilization for achievement of optimal CVD source criteria, and that completion of the coordination sphere around the metal atom requires tuning of both ligand spatial and electronic requirements.
Reaction Kinetics for the Hydrolysis of Titanium Isopropoxide Carboxylate Complexes
Authors: Gagliardi Charles D. , Dunuwila Dilum , Van Vlierberge-Torgerson Beatrice A. , Berglund Kris A. 
Published: March 2011

ABSTRACTTitanium alkoxides modified by carboxylic acids have been widely studied as the molecular precursors to ceramic materials. These alkoxide complexes have also been very useful in the formation of stable, porous, optically clear films having many novel applications such as chemical sensors, catalytic supports, and ion-exchange media. To improve the processing of these materials, it is essential to better understand the kinetics of the chemical transformations which occur.The kinetics of the hydrolysis reaction are studied for selected carboxylic acids using Raman spectroscopy to probe the chemistry of the process. The study has a special emphasis on the titanium isopropoxide-valeric acid system due to the superior quality of these films over other carboxylates. Greater knowledge of the hydrolysis kinetics allows increased control over the quality of the film materials and should be of general interest to those working with modified metal alkoxides.
Usaxs and X-Ray Microscopy Investigations on Silica and Precursors of Zeolites
Authors: Beelen Theo P. M. , Dokter Wim H. , van Garderen Harold F. , van Santen Rutger A. , Browne Mike T. , Morrison Graeme R. 
Published: March 2011

ABSTRACTCombination of SAXS and USAXS measurements provide an extended q-range (0.006–3.0 nm-1) to study fractal growth of both aging silica gel as well as precursors of zeolite-A. Mass (silica) and surface (zeolite) fractals are observed. Scanning transmission X-ray microscopy (STXM) proves to be an extremely useful technique to obtain direct images of wet samples in the 0.1–100 micron range, confirming the SAXS/USAXS results on even larger length scales.