bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Plasma Density and Energy on the Characteristics of Amorphous Silicon Films Prepared by ECR Microwave Plasma CVD
Authors: Tanaka Masahiro , Watanabe Kunihiko , Todoroki Satoru , Suzuki Kazuo 
Published: March 2011

ABSTRACTThe influence of magnetic field on Plasma parameters of ECR plasma were measured by the Langmuir probe technique. And it was shown that the plasma parameters can be controlled by magnetic field. Amorphous silicon films were prepared by ECR plasma CVD method under various magnetic field conditions for the purpose to investigate the effect of plasma density and energy on the property of amorphous silicon films. High plasma density improved the photoconductivity of amorphous silicon but the optical gap and activation of dopant depended on the substrate temperature rather than plasma density.
Synthesis of Al and Al2O3 Coatings by Ion Beam Assisted Deposition
Authors: Kalnas C. E. , Parfitt L. J. , Mashayekhi A. , Jones J. W. , Was G. S. , Hoffman D. W. 
Published: March 2011

ABSTRACTFilms of Al and Al2O3 were formed by physical vapor deposition (PVD) and ion beam assisted deposition (IBAD) onto (100) Si, glass and graphite substrates. Ion to atom arrival rate (R) ratios for IBAD varied from 0.004 to 0.1 and film thicknesses varied from 150 to 1000 nm. The O/Al ratio of oxide films and the oxygen content of Al films decreased with increasing R ratio. Al incorporation into both types of films increased with R ratio up to a value of ∼4 at% at R=0.1. Al films were crystalline with a strong (111) fiber texture becoming more pronounced with increasing R ratio. Film morphology is characterized by large columnar grains at R=0, with a breakup of the columnar structure by R=0.04. Al2O3 films are amorphous under all deposition conditions. Average film stress for PVD Al2O3 films is tensile with a value of 0.68 GPa, becoming compressive at ∼1.3 eV/atom and saturating at a value of ∼-0.65 GPa at R=0.04. Indentation experiments of Al2O3/(100)Si with a 300 g Vickers indenter showed that the changes in crack length are consistent with a model in which the residual film stress is controlling.
Ion-Assisted Deposition of CaF2 Films on (111) Si
Authors: Cook J.G. , Moeller H. , Das S.R. , Zhongming Li 
Published: March 2011

ABSTRACTCaF2 films have been deposited by evaporation onto H-passivated (111) Si in the presence of an rf discharge. The discharge is seen to promote epitaxy. Emission spectroscopy reveals strong CaF2 bands and a weak Ca line, indicating that deposition is largely molecular but that some breakup of the CaF2 molecules occurs in the discharge. Electrical and optical properties of these films were substantially better than those of sputter-deposited films.
MeV Ion Implantation in Electronic Materials
Authors: Todurello T. A. 
Published: March 2011

ABSTRACTUsing MeV ions for the modification of electronic materials offers a number of advantages: minimizing surface damage; implantation into completed devices – for example, through contacts or photoresist layers; producing controlled radiation damage for flux pinning where the ions pass completely through the sample and thus do not modify its chemical nature; and enhancing the electronic excitation of the target material versus collisional damage, as in adhesion enhancement processes. In all cases, however, one requires a detailed understanding of the new damage mechanisms that occur and how they can be modified in a controlled way by annealing. In this report I shall present examples from a number of our experiments: resistivity and index of refraction modification in semiconductors; adhesion enhancement; mixing of multilayer structures; and modification of the electronic properties of insulators and superconductors.
Adhesion Enhancement Produced by MEV Ions
Authors: Sugden Stephen , Sofield Carl J. , Murrell Martin P. 
Published: March 2011

ABSTRACTIonising radiations have been observed to produce significant improvements in thin film adhesion by several experimental groups. We present the results of an exhaustive and conclusive series of experiments on the effect of clean processing and heavy ion irradiation on the adhesion of metal films to substrates of silicon and tantalum. The experiments were performed in a unique research-scale Ultra High Vacuum Cluster tool, to gain control of the all important surface and interface compositions.Our results show that adhesion is greatest for films deposited on atomically clean surfaces. Such films adhere better than conventionally deposited films subjected to a post deposition irradiation treatment. Clean processed samples show no benefit from subsequent radiation processing. Our results are consistent with the radiation enhanced adhesion phenomenon being due to the radiolysis of interfacial contaminant layers, producing an interface with lower interfacial energy and hence better bonding. Where adhesion enhancement is observed, the process is consistent with a semi-empirical model of the process using an activation energy of some 5 eV per atom.
XPS Study of Chemical Interactions in Ion-Implanted Silica Glasses
Authors: Bertoncello Renzo , Glisenti A. , Granozzi G. , Battaglin G. , Cattaruzza E. , Mazzoldi P. 
Published: March 2011

ABSTRACTAn almost unexplored research field of the ion implantation processes is related to chemical modifications induced in a target by chemically reactive ions. This kind of chemistry is somewhat similar to the “hot atom” chemistry, where chemical transformations are produced by recoil atoms originating from nuclear reactions or radiative decay. XPS technique can provide unique informations on the chemical modifications produced by such processes. XPS results will be reported on silica glasses implanted with titanium, silver and tungsten ions in a dose range from l×1016 to 5×1016 ions cm−2, at energies ranging from 15 keV to few hundreds of keV. Most of samples were also subjected to a second implant with N ions. Radiation damage and chemical effects have been discriminated. Chemical compound formation as well as precipitation of the implanted species have been observed. Interestingly, evidences for reactions between chemical species obtained by the first implant and nitrogen (subsequently implanted) will be reported.
Ultra-Low Damage Chemical Etching of GaAs with a Novel Ion Beam Source
Authors: Beckman Judith , Jackman Richard B. 
Published: March 2011

ABSTRACTA novel ion beam source has been successfully used in both a CAIBE and RIBE configuration, with chlorine as the chemically active gas, to achieve GaAs etching a rates of around 0.1 µm/hour. The energy of species within the beam from the source is estimated at 10 - 25eV. Under these conditions it can be expected that little or no penetration into the GaAs lattice occurs and that the principle origin of lattice disruption, prior to etching, is chemical; a low damage GaAs etching process results. The source, however, gives rise to a coating, derived from the source liner, which must be washed from all etched samples. The presence of such a coating is likely to be the origin of the slow etch rate achieved. After removal of the coating, smooth, mirror like etched surfaces are apparent. These surfaces perform very well when Schottky diodes are constructed from them showing no deviation from the behaviour of control samples.
Surface Modification of Uranium Alloys by Ion Implantation and Ion Mixing - Effects on Corrosion Behavior
Authors: Ayral A. , Crusset D. , Raboisson G. 
Published: March 2011

ABSTRACTIon implantation and ion mixing are applied to improve the corrosion behavior of two uranium alloys: UV0.2 and UTi0.75, in three specific media: hydrogen, humid air and salt fog. This experiments shows particularly that high dose nitrogen implantation might be effective for both corrosive environment, hydrogen and humid air. Ion mixing of aluminum coatings on UTi0.75 alloy induces microcracks in these films and reduce their protective characters in salt fog medium.
Reactive Magnetron Sputtering: In Situ Analyses of Particle Fluxes and Interactions with the Growth Surface
Authors: Abelson J. R. , Doyle J. R. , Mandrell L. , Maley N. 
Published: March 2011

ABSTRACTReactive magnetron sputtering (RMS) is a versatile technique for the production of alloy thin film coatings such as hydrides, nitrides, oxides, etc. RMS provides control over (i) film stoichiometry, via the partial pressure of “reactive” gas (H2, N2, etc.) injected, and (ii) film microstructure, via the bombardment of the growing surface by fast neutral or accelerated ionic species. However, few details are known about the fluxes reaching the film surface, and their reactions with it.This paper reports comprehensive measurements for the RMS growth of hydrogenated amorphous silicon (a-Si:H). The analysis techniques are in situ double modulation mass spectroscopy, plasma probes, isotope replacement experiments, and Monte-Carlo simulations of sputtered particle transport. We determine (i) the composition, energy and angular distributions of the incident flux, (ii) the H coverage of the growing surface, and (iii) the release of H2 from the growing film. For conditions which produce electronic quality a-Si:H, the total H flux arriving at the substrate varies between 0.5–2 times the depositing Si flux; about half of the H flux reflects. The growth surface has excess H varying between 0.5–2 × 1015/cm2, and this surface H coverage is linearly related to the bulk H incorporation. We also find evidence that film density varies with the energy of the arriving sputtered Si atoms.
Amorphization of Thin Multilayer Films by Ion Mixing and Solid State Reaction
Authors: Van Rossum M. , Shreter U. , Johnson W. L. , Nicolet M-A. 
Published: March 2011

ABSTRACTWe have compared the formation of amorphous alloys from Ni-Hf multilayer films by ion mixing and solid state diffusion. We find that ion mixing and solid state reaction produce significant differences in the composition range of the amorphous phase inside the mixed samples. Moreover, the thermochemical parameters which are of primary importance for the solid state reaction also influence the behavior of the Ni-Hf system under ion mixing.
Ion Mixing Kinetics of Thin Layered Films in the Fe-Al System
Authors: Grilhe J. , Riviere J.P. , Delafond J. , Jaouen C. 
Published: March 2011

ABSTRACTEvaporated bilayers and multilayers of Fe and Al have been studied during ion beam mixing with Xe ions using in-situ electrical resistivity measurements. Experiments have been performed in the composition range 40 – 58 at.% Al and at both temperatures 77 K and 300 K. A semi-empirical model is proposed to explain the observed kinetics. At low doses, a square root dependence of the mixed volume fraction on dose is found at 77 K but not at 300 K. The results are discussed by comparison with the different models proposed for ion beam mixing.
Modulated Structures in Ion Implanted Al-Fe System
Authors: Jata K.V. , Janoff D. , Starke E.A. 
Published: March 2011

ABSTRACTThe results of transmission electron microscopy studies of iron implantation into high purity aluminum foils are described. For both 50 and 100 + 50 keV incident ion energies, modulated structure has been detected in the as-implanted foils. Upon annealing at 793 K the modulated structure decomposes into the Al matrix and Al3Fe precipitates for the 50 keV implantation. A similar annealing treatment for the 100 + 50 keV implantation indicates that the modulated structure is more stable, although some Fe3Al precipitation occurs.
The Dependence of Ion Beam Mixing on Projectile Mass
Authors: Averback R. S. , Thompson L. J. , Rehn L. E. 
Published: March 2011

ABSTRACTIon beam mixing in Pt-Si bilayered samples was measured during irradiation with projectiles ranging in mass from 4 amu (He) to 131 amu (Xe) at 10 K, 300 K and 373 K. Using deposited damage energy as a basis for comparing the different irradiations, it was found that the beavier ions were more efficient than the lighter ones for inducing mixing. Moreover, it was observed that the mixing was essentially independent of temperature below 373 K. These results are interpreted on the basis that the mixing is caused by the stimulated motion of defects during the cooling phase of energetic cascades.
The Influence of Implantation Conditions and Target Orientation in High Dose Implantation of Al+ into Si
Authors: Nam-Avar F. , Budnick J. I. , Fasihuddin A. , Hayden H. C. , Pease D. A. , Otter F. A. , Patarini V. 
Published: March 2011

ABSTRACTWe report the preliminary results of a study to determine the dependence of the near surface composition and structure on total dose, dose rate, vacuum condition and substrate orientation for Al implantation into Si (111) and Si (100) with doses up to 2 × 10l8 ions/cm2. Our studies include the results of Rutherford Back Scattering (RBS), Auger Electron Spectroscopy (AES) and x-ray diffraction measurements on samples implanted with a 100 keV energy in a diffusion pumped vacuum (DPV) system (10−6 Torr) with and without a LN2 trap and in an ultra high vacuum (UHV) system (2–4) x 10−8 Torr.Results of high dose rate (50 μA/cm2 ) implantation into Si (111) in an untrapped DPV system indicate that Al segregates with a preferred (111) orientation. For a dose of 1 × 1018 ions/cm2 the surface is Al-rich to a depth of 2500Å while for lower doses the surface is silicon-rich. A carbon build-yp occurred for samples prepared by low dose rate (5 μA/cm2 ) implantation. However, no Al segregation could be observed for doses of less than 1018 ions/cm2 . A similar behavior has been observed for Si (100) except that Al segregation occurs with a polycrystalline structure. Moreover, the segregated Al is present at depths greater than the projected range.When implantation was carried out in a DPV system with a LN2 trap, no carbon peaks could be observed by RBS regardless of the dose rate. For these conditions, as well as for the implantation of Al in an UHV system, we find Al segregation with a polycrystalline structure independent of the dose rates and target orientations we used. Al is observed at a depth greater by a factor of two than the expected value from the Rpcalculations. The Al depth penetration increases with the dose of implantation.
Characterization of Ion Implantation Damage in Capless Annealed GaAs
Authors: Kanber H. , Feng M. , Whelan J. M. 
Published: March 2011

ABSTRACTArsenic and argon implantation damage is characterized by Rutherford backscattering in GaAs undoped VPE buffer layers grown on Cr-O doped semi-insulating substrates and capless annealed in a H2 −As4 atmosphere provided by AsH3. The damage detected in the RBS channeled spectra varies as a function of the ion mass, the implant depth and the annealing temperature of the stress-free controlled atmosphere technique. This damage is discussed in terms of the stoichiometric disturbances introduced by the implantation process. The as-implanted and annealed damage characteristics of the Ar and As implants are correlated to the electrical activation characteristics of Si and Se implants in GaAs, respectively.
Ion Implantation of Polymers
Authors: Dresselhaus M.S. , Wasserman B. , Wnek G.E. 
Published: March 2011

ABSTRACTIon implantation provides a mechanism for radically modifying the electronic and transport properties of a variety of polymers that are normally insulating. By using masks and tailoring the implanted species and ion energies, conducting paths in an insulating medium can be fabricated between specific reference points, an application of obvious relevance to the microelectronics industry. Specific results are reported for modification of the structure, electrical conductivity, thermoelectric-power, optical transmission and electron spin resonance for several polymers under a variety of implantation conditions. The temperature and frequency dependence of the conductivity suggest a onedimensional variable range hopping mechanism for conduction along the polymer chains. Comparison is made between implantation in the 200 keV and 2 MeV energy ranges.
Structure/Majority Carrier Relationships in Ion-Implanted Polymer Films
Authors: Wnek G. E. , Wasserman B. , Loh I.-H. 
Published: March 2011

ABSTRACTIon implantation of selected polymer films leads to the formation of semiconductive (σ ~ 10−4 S/cm) derivatives, which are presumably partially carbonacėous products derived from gross structural rearrangements. In support of this contention we find that Br-implanted polyacrylonitrile, PAN, exhibits a narrow ESR signal with a g-value of 2.0033, consistent with the presence of free radicals delocalized within a П-electron system. Thermopower measurements reveal that the sign of the majority carrier is dependent upon the molecular structure of the parent polymer.For example, implantation of PAN with Br+ affords n-type derivatives while under similar conditions poly(p-phenylene sulfide), PPS, and poly(2,6-dimethylphenylene-oxide), PPO, yield p-type semiconductors. It is suggested that the majority carriers arethe ions (carbenium ions or carbanions) which are best stabilized by the parent polymerstructure, remnants of which presumably exist after implantation. Resonance and/or inductive effects are invoked to explain the data. For example, the rather electron-rich backbone of PPQ is expected to stabilize holes more effectively than electrons, and the observed p-type behavior is consistent with this prediction.
Two-Dimensional Ordering of Ion Damaged Graphite
Authors: Elman B.S. , Dresselhaus S. , Braunstein G. , Dressflhaus G. , Venkatesan T. , Wilkens B. , Gibson J.M. 
Published: March 2011

ABSTRACTPost implantation annealing of ion-damaged, highly oriented pyrolytic graphite (HOPG) has been studied by Raman spectroscopy, the ion channeling technique and Transmission Electron Microscopy. Complementary information obtained by these methods provides confirmation for the completion of the first step of graphitization of iondamaged graphite at annealing temperatures of ~2300°C. This is manifested by the formation of carbon planes with two dimensional ordering but no correlation in the third (c-axis) dimension.
Maskless Patterning of Cr Films Using Focused Ion Beams
Authors: Gamo K. , Moriizumi K. , Matsui T. , Namba S. 
Published: March 2011

ABSTRACTCharacteristics of maskless patterning of Cr films using focused Sb+ ion implantation have been investigated. Dose and depth dependence of the etching rate of Sb-implanted layers during plasma etching using CCl4 were measured. Sb profiles were also measured by Rutherford backscattering techniques. It was found that a sharp threshold dose exists to form an etch-resistant layer by Sb implantation. It was also found that a latent image of an Sb implanted pattern at a dose ≥3.8×1015/cm2 was developed by the plasma etching, and that Cr patterns with a thickness of a few hundred nanometers were formed by the present maskless patterning technique.
Ion Irradiation Smoothing and Film Bonding for Laser Mirrors
Authors: Pronko P. P. , Mccormick A. W. , Ingram D. C. , Rai A. K. , Woollam J. A. , Appleton B. R. , Poker D. B. 
Published: March 2011

ABSTRACTIrradiation with high energy heavy ion beams has been investigated as a technique for improving the quality of highly reflecting metallic surfaces to be used as laser mirrors. Properties such as reflectivity, corrosion resistance, film bonding, and threshold to laser surface damage have been examined. Modifications of composition and microstructure of the material associated with the heavy ion irradiation have been measured with RBS, TEM, SEM, Auger, and ESCA. Reflectivity and extinction coefficient measurements were made using ellipsometry techniques. Observations indicate that keV heavy ion irradiations in the fluence range of 1015 to 1016 cm−2 produce significant surface smoothing. Additionally, MeV implants of heavy ions into films of Cu, Ag, Au and Al deposited on molybdenum substrates resulted in improvements to both tarnish resistance and structural bonding integrity.
Radiation Enhanced Diffusion in Ion-Implanted Glasses and Glass/Metal Couples
Authors: Arnold G. W. 
Published: March 2011

ABSTRACTIon implantation causes alkali migration to the surface in alkali silicate glasses. Rutherford backscattering spectrometry was used to follow this depletion. Room temperature implantations of 5×1016 250 keV Xe/cm2 in 12M20·88SiO2 (M = Li,Na,K,Rb,Cs) removes approximately equal numbers (within a factor of 2) of alkali from the glass. Low temperature (77K) implants significantly reduce the alkali loss. These results imply a radiationenhanced diffusion mechanism in which the alkali interchanges with the products of the collision cascade, with the kinetics being limited by the radiation damage components. The results for mixed-alkali glasses ((12−x)M2O·xCs20·88Si02) give further evidence for this process. In glass/'metal couples, radiation enhanced diffusion allows the interchange of glass network components with deposited metals. Rutherford backscattering spectrometry was used to follow the interchange of silicate and phosphate glass components with metal ions near the heavy-ion implanted interface between glass substrate and metal (Al,Zr) films.
The Characterization of Nitrogen Implanted WC/Co
Authors: Oblas Daniel W. 
Published: March 2011

ABSTRACTAlthough the mechanical properties of nitrogen implanted cemented carbides show significant improvements in performance over unimplanted specimen, the chemical or physical mechanisms giving rise to these improvements are not well understood. Furthermore, the mechanical properties of the implanted samples under thermal stress may not be stable. This study presents analytical results obtained for a series of nitrogen implanted cemented carbides that were subsequently characterized by Auger Electron Spectrometry (AES) and Thermal Desorption Mass Spectrometry (TDMS). Results show that, in the fluence range of 0.5 to 2.5×1017 N2/cm2, peak nitrogen concentration is linear and reaches a maximum concentration of 25 a/o for the highest fluence and 180 keY energy. During vacuum heating, the implanted nitrogen is evolved rapidly between 600–700°C, which corresponds to an activation energy of approximately 7 kcal/mole (.30 ev). A small quantity of nitrogen is still present after heating to 1000°C, at an estimated average concentration of 3 a/o with little diffusional broadening as a result of post-implant heating.
Processing Steels for Tribological Applications by Titanium Implantation
Authors: Singer I.L. , Jeffries R.A. 
Published: March 2011

ABSTRACTTitanium implantation into steels has been shown to produce superior tribological surfaces. The fluence required to produce a wear resistant surface increases from 2 to 5×1017 Ti/cm2 as the energy increases from 50 to 200 keV/ion. On curved surfaces (e.g., bearings, cutting tools, etc.) higher fluences are necessary due to effects of implantation at angles off normal incidence (i.e. the combined effects of higher sputtering rates, decreased range, and changes in the carburization process associated with duty cycles). Significant improvements in friction and wear have also been observed for surfaces which have been abraded by 600 and 120 grit SiC prior to implantation. Optimal benefits of Ti-implantation are associated with the formation of a modestly thick (>20nm) fully carburized layer.
Ion Mixing in the Ni-Sn System
Authors: Calliari L. , Gratton L.M. , Guzman L. , Principi G. , Tosello C. 
Published: March 2011

ABSTRACTNickel substrates were coated with a thin Sn film and implanted with 100 keV Xe+ to fluences between 3 and 7.1015 ions/cm2. Surface chemistry changes were monitored using Auger and Mfssbauer spectroscopies. By comparing between profiles of un-implanted and implanted specimens, it was found that ion implantation through the film caused Ni to move into the Sn film and Sn to penetrate into the Ni substrate. The Mdssbauer analysis disclosed the presence of new surface phases. A substantial increase in the tarnishing resistance of Ni was found by using this treatment.