bluuebunny/crossref_metadata_2025 huggingface dataset:
Corrosion of Aluminum Interconnect Passivated with Polyimide or Silicon Nitride
Authors: Comizzoli R. B. , Opila R. L. , Wong Y. H.
Published: March 2011

Polyimides have been considered the most promising organic polymers for use as an inner-layer dielectric or over-metal passivation layer on ICs. These polymers have certain processing advantages over traditional inorganic dielectrics such as SiO2 or Si3N4. However, polyimide (PI) must meet the stringent standards that inorganic materials have met, including good adhesion to the substrate and resistance to diffusion of water. Failure to meet these standards may result in increased aluminum corrosion rate and consequent degraded reliability.
Adhesion of Copper to Polytetrafluoroethylene
Authors: Kim Yong-Kil , Chang Chin-An , Schrott A. G. , Andreshak J. , Cali M.
Published: March 2011

An enhancement of the adhesion between copper and polytetrafluoroethylene (PTFE) has been studied. Thin-films of copper were electron-beam deposited on the surface of the polymer substrates. Peel test measurements showed that, without any treatment of the substrates, the adhesion was poor with a peel strength of 1–2 g/mm. A pronounced enhancement of the adhesion has been obtained when the fluorocarbon substrates were treated by either an ultraviolet (UV) irradiation, an ion-beam presputtering prior to the metal deposition, or heat treatments after the deposition. Among the treatments employed, the ion-beam sputtering was the most effective in improving the adhesion. The roles of the treatments and possible reasons for the enhanced adhesion are discussed in conjunction with the studies of interface morphology and chemistry using Scanning Electron Microscopy, Rutherford Backscattering Spectroscopy, and X-ray Photoelectron Spectroscopy.
The Aspects of Thermal Anneal to Intrinsic Stress and Microstructiire of Multilayer Thin Films
Authors: Yang C. H. , Chen P.C.
Published: March 2011

Adhesion degradation mechanism at the interface of a multilayer thin film was studied as a function of annealing temperature. The multilayer thin films employed for current investigation of the temperature effect were constructed by sputtering 500 Å Cr and 10K Å Cu on both sides of kapton. A steady decrease of adhesion strength was found as a result of increasing the annealing temperature from 150°C to 350°C. Thin film and interfacial properties in association with degradation of adhesion were characterized by several techniques, including intrinsic stress measurement, Auger, TEM and SIMS. Siveral changes were observed by elevating the annealing temperature. It was found that the intrinsic stress in each layer changed. Both Cu and Cr grain size increased with the annealing temperature. The interface at kapton and metal became more defined. The Cu atoms were found to become mobile and diffused into Cr and kapton layer after a 350 degree annealing. In addition, a change of molecular orientation and chemistry in kapton near the interface was observed by SIMS and XPS studies. A combination of these factors resulted in a decline of adhesion strength.
XPS Study of Polyimide H-Film After Heat Treatment and Laser Processing
Authors: Nagarkar P.V. , Sichela E.K. , Doll G.L.
Published: March 2011

An x-ray photoelectron spectroscopy (XPS) study of laser treated and heat treated Kapton®indicates that both the treatments result in depleting the carbonyl groups from the sample and leave behind a conducting residue that still contains significant amounts of oxygen and nitrogen. The rapid changes in surface composition coincide with a substantial decrease in the electrical resistivity of the polyimide samples.
Dielectric, Conducting, and Photonic Polymers for Devices in Multichip Packaging
Authors: Mcdonald John F. , Vlannes Nickolas P. , Wnek Gary E. , Lu Toh-Ming
Published: March 2011

Polymeric materials have traditionally enjoyed widespread use in the electronics industry. Recent advances in the identification and synthesis of polymers with unusual electrical and optical properties have opened new opportunities for technological applications. Some of these novel properties are summarized in this paper with an emphasis on how these properties may be usefully exploited in the area of multichip packaging.
Materials Problems Affecting Reliability and Yield of Wire Bonding in VLSI Devices
Authors: Harman George G. , Wilson Charles L.
Published: March 2011

Materials problems have always been a significant cause of wire bond failures in microelectronics. However, modern VLSI materials, processing, and packaging methods combined often result in new or masked versions of old failure mechanisms. This paper describes the classical Au-Al intermetallic compound problem as described by a new two-dimensional finite element diffusion model and demonstrates that diffusion in poor welds is more rapid than in bulk couples. Failures resulting from modern bonding material couples (e.g., Cu-Au, Al-Ag, etc.) can result in bond failures superficially resembling Au-Al type failures. Failures resulting from bonds made to contaminated gold electroplated films are described, and a new failure model resulting from hydrogen in these films is shown.
A Model of Thermal Stress Development in Microelectronic Components
Authors: Scott Geoffrey C. , Astfalk Greg
Published: March 2011

A model to characterize the development of thermal stresses in printed wiring board (PWB)-mounted multilayer ceramic capacitors (MLCC's) is presented. The model is developed analytically using uncoupled, quasi-static thermoelastic theory. Both the actual 2D geometry and mechanical and thermal properties of real MLCC-PWB structures are incorporated in the model. A particular method for solving the model equations is presented and implemented. Preliminary numerical results indicate that the values and spatial patterns of stress are in agreement with data available in the experimental literature.
Mechanisms for Conduction Pathway Formation in Polymer Encapsulants
Authors: Anderson J. E. , Hoffmann D. A. , Frank C. W. , Bousse L. J.
Published: March 2011

This article concerns physicochemical mechanisms leading to formation of local heterogeneous structures in bulk polymers. Previous experimental work suggests that such heterogeneities are related to ionic conduction and electrochemical attack on encapsulated microelectronics. Six mechanisms are discussed: (a) Macrosyneresis; (b) Osmotic swelling; (c) Liquid-liquid phase separation; (d) Microsyneresis; (e) Polymer fracture during solvent sorption/desorption; (f) Polymer-substrate interactions.
Preparation of Spherical Titania Particles from Inorganic Precursor by Homogeneous Precipitation
Authors: Kato A. , Takeshita Y. , Katatae Y.
Published: March 2011

Spherical titania particles can be prepared in a short time period from an aqueous solution of TiOSO4 by homogeneous precipitation using urea at 70–90°C. Although the hydrolysis of TiOSO4 continues to a considerable extent even in the absence of urea, the presence of urea is essential for the formation of spherical particles. The average particle size produced was l–4μm and changed mainly with the concentration of TiOSO4. As-synthesized powders are amorphous hydrates of titania containing sulfate group and crystallize by calcination into anatase(>500°C) and rutile(>900°C). In calcination, the particles shrink, but hold their original spherical shapes.
Sol-Gel Networks: Fundamental Investigations of the Chemistry of Sol-Gel Silicate Glasses and Poly(Siloxane) Toughened Silicates
Authors: Spinu M. , Mcgrath J. E.
Published: March 2011

The low-temperature sol-gel process opens a number of new materials possibilities for generation of glasses with predetermined properties by the incorporation of organic modifiers into the network. Polysiloxanes are potentially interesting organic modifiers for toughening and possibly surface-modifying the silicate networks. Some fundamental studies of the hydrolysis and condensation processes in a tetramethylorthosilicate (TMOS) system, in the absence of added catalyst, have been conducted using 1H and 29Si NMR. The effects of some of the reaction parameters and processing conditions for the subsequent conversion of the gel to monolithic dried gels by heat treatment have been investigated by techniques such as thermal analysis and mass spectroscopy. Procedures which employ mild pressures have been established that permit the generation of monolithic products which show greatly reduced cracking tendencies. Finally, methoxy functionalized poly(dimethylsiloxane) oligomers that can react into the sol-gel network have been prepared. The intermediates are commercially accessible and the process is scaleable. Utilization of a catalyst-free system eliminates the tendency of the siloxane modifier to undergo undesired rearrangements that are known to occur in the presence of strong acids or bases.
Barriers to the Nucleation of Methyl Groups on the Diamond (111) Surface
Authors: Valone Steven M.
Published: March 2011

Questions about the mechanism of diamond film growth by low-pressure, plasma-assisted chemical vapor deposition methods have persisted for some time now. As an attempt to explore one aspect of the problem, we examine the energetics of several adsorbed diamond (111) surfaces. The adsorbates are mixtures of methyl groups and hydrogen atoms. The model for these systems is the molecular orbital hamiltonian of Dewar and coworkers.

From these calculations we find that H adsorbtion is preferred due both to bond energy and steric effects. Thus, nucleation of a cluster of three or more methyl groups, as assumed in earlier work, is energetically very demanding.
Processing of SiC-Whisker Reinforced Si3N4
Authors: Hoffmann M. J. , Nagel A. , Petzow G.
Published: March 2011

Cold isostatic pressed (CIP) and slip cast Si3N4 composite materials containing up to 20 vol.% SiC-whiskers were densif led by pressureless
sintering and post-HIPing. The slips were characterized by viscosimetry and showed no influence of whisker loading on the rheology of the highly concentrated aqueous suspensions up to 15 vol.! whiskers. During casting the whiskers were preferentially aligned parallel to the mould surface and the CIPed samples showed a 3-dimensional random whisker distribution. The influence of the whisker length and orientation on the densification behaviour was studied in a high-temperature dilatometer. While the CIPed samples exhibit an isotropic shrinkage behaviour, the slip cast samples showed a strong shrinkage anisotropy with a maximum linear shrinkage of 21% perpendicular and only 7% parallel to the whisker plane for the samples with 20 vol.% whiskers. With increased whisker loading, the sintered densities decreased from 0.99 to 0.88 fractional density. The poor sinterability of the composites was attributed to the sintering stresses around the non-sintering SiC- whiskers and the formation of a whisker network which inhibits further shrinkage in the final stage of sintering. Thermodynamic calculations show the optimum fabrication conditions for SIC-whisker reinforced Si3N4-composites.
Structural Transitions induced by Colloidal Interactions in Ceramic Dispersions
Authors: Rajagopalan Raj
Published: March 2011

A discussion of the formation of periodic colloid structures, liquid-like ordering, and compact and fractal aggregates caused by colloidal forces in ceramic dispersions is presented. Construction of phase diagrams based on simple forms of repulsive potentials is often not adequate, and it is important to include appropriate attractive interactions in the theoretical analyses. Examples of radial distribution functions, osmotic prsueadphase diagrams are given for dispersions interacting through Derjaguin-Landau-Verwey-Overbeek potentials. Densification of colloidal aggregates dlue to positional relaxation and the effects of such densification on the structure of the aggregates are discussed.
Flow of Dispersions Near Close Packing
Authors: Marshall L. , Zukoski C. F.
Published: March 2011

The flow of hard sphere-like suspensions near close packing is explored. The change in viscosity with stress and volume fraction shows that at volume fractions above 0.5 shear thickening occurs and that the characteristic shear rates for shear thinning and shear thickening decrease rapidly above this volume fraction. The creep compliance is well characterized by a stretched exponential relaxation time spectrum above volume fractions of 0.52. These results suggest that the limiting volume fraction where the zero shear rate viscosity diverges is determined by a liquid/glass phase transition very similar to that predicted for hard sphere liquids.
Electronic Properties of some Ternary and Quaternary Oxides of the VIII B and I B Transition Elements: Application to High TcSuperconductivity
Authors: Pouchard M. , Grenier J-C. , Doumerc J-P. , Demazeau G. , Chaminade J-P. , Wattiaux A. , Dordor P. , Hagenmuller P.
Published: March 2011

In the scope of the Goodenough model, a brief review of the electronic properties of some 3d transition elements (M = Fe, Co, Ni and Cu ) is given; the main relevant electronic and structural parameters are emphasized. Then a special attention is focussed on N/(N−1) and N/(N−2) electron mixed valence compounds.

Finally some particular features of copper are discussed and their relevance to high Tc superconductors is pointed out:

-the srong covalency of Cu-O bondings involving a possible delocalization of the hole between trivalent copper and oxygen,

-the existence of low and high spin electronic configurations for CuIII,

-the disproportionation of Cu2+and its role in the formation of hole pairs,

Cu-O distances very close for the three successive oxidation states of copper favouring the disproportionation process.
Annealing and Strain Effects on Tl-Ba-Ca-Cu-O Crystals and Ceramics
Authors: Venturini E. L. , Morosin B. , Ginley D. S. , Kwak J. F. , Schirber J. E. , Baughman R. J. , Graham R. A.
Published: March 2011

Superconducting transition temperatures (Tc'S) in the Tl-Ba-Ca-Cu-O system are shown to be a function of processing for both single crystals and bulk ceramics. Crystals with the identical structural phase and nominal composition but slightly different lattice constants can have significant differences in Tc. We report the effects of high temperature annealing in vacuum or flowing oxygen on Tc for single crystal plates of two common phases with nominal stochiometries Tl2Ba2Ca1Cu2O8 and Tl2Ba2Ca2Cu3O10. Contradictory results on nominally similar crystals suggest that strain, Tl content and TI/Ca site disorder are as important as the oxygen stoichiometry in determining Tc This interpretation is supported by complementary annealing studies in bulk ceramic, including a powder where Tc increased by 5 K following high-pressure shock loading which introduced substantial residual strain.
Synthesis and Properties of the High Tc Bi-Pb-Sr-Ca-Cu-O Superconductors
Authors: Endo Utako , Koyama J. , Kawai T. , Okazaki N. , Kitazawa K. , Matsui Y.
Published: March 2011

A single high Tc phase of Bi-Pb-Sr-Ca-Cu-O superconductor was obtained by following proper synthetic conditions:(a)addition of Pb, (b)proper starting composition, (c)codecomposition method, (d)sintering under low oxygen partial pressure and (e)long sintering. The composition analysis showed that every atomic site might be occupied by some element and there might not be defects or excess atoms in the structure. The hole donor in these samples is considered to be Pb on the Bi site and hole concentration seems to be, to some extent, controlled by the Pb content. A phase with four CuO2 layers have possibly grown on the surface of the grains of thi high Tc phase.
Structural and Electronic Relationships in the High-Temperature Copper-Based Superconductors
Authors: Torardi C.C. , Jung D. , Kang D.B. , Ren J. , Whangbo M.-H.
Published: March 2011

Atomic displacements from the ideal rock-salt positions in the Tl-, Bi-, and Pb-O layers of the Cu-based high-Tc super-conductors affect the electronic nature of these oxides. When distortions in the Bi-O layers of Bi2Sr2CaCu2O8 are considered, the bottom of the Bi 6p band is found to lie more than 1 eV above the Fermi level. Displacements in the double Tl-O layers of Tl2Ba2Can−1CunO2n+4 places the bottom of the Tl 6s bands significantly below the Fermi level showing that electrons can be removed from the x2-y2 bands of the CuO2 layers. However, this is not the case for the thallium-oxygen single layers of Tl2Ba2Can−1CunO2n+3. Correlations between the superconducting transition temperatures, Tc, and the in-plane Cu-O bond lengths, rCu−O', of the Tl- and Bi- based copper-oxide super-conductors reveal Tc vs rCu−O characteristics similar to those found for La2−xSrxCuO4.
Barium Potassium Bismuth Oxide Synthesis and Physical Properties
Authors: Ott K. C. , Hundley M. F. , Kwei G. H. , Maley M. P. , McHenry M. E. , Peterson E. J. , Thompson J. D. , Willis J. O.
Published: March 2011

A series of compounds Ba1−xKxBiO3 have been prepared and characterized over the range of compositions ranging from x = 0.3 to 0.5. A neutron powder diffraction analysis has been carried out for the composition x = 0.4 at room temperature and at 10 K. Examination of the superconducting properties as a function of x indicates superconductivity occurs over a narrow range of compositions close to x = 0.4, with Tc of 29 K. Specific heat measurements indicate conventional electron-phonon interactions may play a role in promoting superconductivity in Ba.6K.4BiO3. Magnetization loops and examination of the time dependent magnetization indicate that Ba.6K.4BiO3 has a low value of Jc due to very weak pinning.
Some Aspects of the Nonstoichiometric and Thermodynamic Behavior of the YBa2Cu3Oz System
Authors: Tetenbaum M. , Curtiss L. , Czech B. , Tani B. , Blander M.
Published: March 2011

The nonstoichiometric and thermodynamic behavior of the YBa2Cu3Ox system as a function of oxygen partial pressure and temperature is being investigated by means of a coulometric titration technique. The oxygen content of the superconductor can be varied coulometrically by well-defined small amounts and the equilibrium partial pressures determined from the EMF. The oxygen stoichiometry in YBa2Cu3Ox as a function of oxygen partial pressure shows a change of curvature around x = 6.55–6.75 and an inflection around x ≅ 6.65 at temperatures between 400–500°C. These new low temperature data are consistent with the presence of a miscibility gap at lower temperatures, which is similar to that postulated in several theoretical papers.
Oxygen Nonstoichiometry and Related Problems of High-TcOxide Superconductors Investigated by Thermogravimetry
Authors: Kishio K. , Hasegawa T. , Suzuki K. , Kitazawa K. , Fueki K.
Published: March 2011

Thermogravimetry (TG) is a sensitive and powerful tool for investigation of oxygen nonstoichiometry and related properties in mixed-valence oxide systems and has been extensively applied to a series of high-Tcoxide superconductors. Nonstoichiometry, phase stability ranges, and oxygen diffusion as investigated mainly through the TG technique in several systems of high-Tcoxides are reviewed.
Preparation and Characterization of Ion Beam Assisted Aluminum Oxide Films
Authors: Hirvonen James K. , Tetreault T.G. , Parker G. , Revesz P. , Land D. , Price J. , Simons D. , Stern S.
Published: March 2011

The ion beam assisted deposition (IBAD) technique has been employed to make aluminum oxide optical coatings. Deposition variables include aluminum oxide evaporant to oxygen ion beam flux ratios, substrate temperature, and ion energy. Characterization included optical ellipsometry, ion beam analysis, and adhesion tests. Films deposited with the aid of ions exhibited the highest refractive indices and best adhesion to their substrates.
Ion-Beam Synthesis of Buried Yttrium Silicide
Authors: Alford T.L. , Barbour J.C.
Published: March 2011

Buried single-crystal YSi1.7 layers have been synthesized using high fluence implants of 330 keV yttrium ions into (111) Si held at 450°C followed by post-implant anneals of 1000°C . Rutherford backscattering spectrometry showed that an implant fluence of 3.6 X 1017 Y/cm2 forms a continuous layer of uniform thickness. Whereas, implant fluences of 1 — 2 x 1017 Y/cm2 form a thin continuous YSi1.7 layer with what are believed to be Y-silicide precipitates above and below the YSi1.7 layer. Strains resulting from the YSi1-7 layers were evaluated from x-ray rocking curves using a double crystal diffractometer.
Formation of Buried Oxynitride Layer into Silica Glass using Ion Beam
Authors: Oyoshi Keiji , Tagami Takashi , Tanaka Shuhei
Published: March 2011

Both silicon and nitrogen implanted silica glasses were characterized by SIMS, XPS and SEM. Bubbles appeared in the implanted region at the high dose implantation (the silicon to nitrogen dose ratio is 0.75 and the total dose is 4×10 ions/cm2). Suppression methods of bubble formation were discussed concerning about the nitrogen implantation.
Effect of Implantation Conditions on the Microstructure of High-Current, Oxygen Implanted Silicon-on-Insulator Material
Authors: Visitsemgtrakul S. , Cordts B.F. , Krause S.
Published: March 2011

Conventional and high resolution electron microscopy were used to study structural development in silicon-on-insulator material produced by oxygen implantation at temperatures of 525 to 700°C, doses of 0.3 to 1.8 × 1018 cm-2, and current densities of 1 and 10 mA/cm2. Implantation temperature has the strongest effect on the microstructure and defect formation, both in as-implanted and annealed material. In the top silicon layer of as-implanted SIMOX, oxygen bubbles form near the surface when the wafer temperature is ≥ 550°C. A new type of defect, the multiply faulted defect (MFD), has been observed at the upper edge of the implantation region with a density of 108 cm-2 in the samples implanted at the temperature of ≥ 600°C. As dose increases from 0.3 to 1.8 × 1018 cm-2, the bubbles grow larger and the trails of bubbles lengthen while the character and density of MFDs remain the same. A continuous buried oxide layer forms at doses ≥ 1.5 × 1018 cm2. No significant difference in structure is observed when a current-density increases from 1 to 10 mA/cm2.
Mechanism of Ion-Induced Solid-Phase Crystallization and Amorphization
Authors: chaki T.k.
Published: March 2011

A mechanism is proposed to explain ion-induced solid-phase epitaxial growth (SPEG). It is argued that radiation-enhanced diffusion in amorphous solid is the cause of ion-induced SPEG at relatively low temperatures. The atoms in the amorphous solid near the crystalline/amorphous interface adjust their positions to lattice sites due to a free energy decrease associated with the transformation from amorphous to crystalline solid. An expression for the velocity of ion-induced SPEG is derived. At low temperatures and high irradiation dose rates, a large number of atoms in the lattice gets displaced and the free energy of the crystalline solid can increase to such a value that the crystalline/amorphous interface may remain stationary. It is shown that the dose rate at which the interface remains stationary increases with the temperature, following an Arrhenius dependence.
Adhesion Studies of Au Films on GaAs using Ion-Assisted Deposition Techniques
Authors: Kellock A.J. , Bardin T.T. , Wang P-W. , Baglin J.E.E. , Pronko J.G.
Published: March 2011

A series of experiments have been performed to examine the ability of ion beam assisted thermal deposition to produce good adhesion of Au metallization on GaAs <100> substrates. A study of the influence of Ar ion-assisted thermal deposition of the Au films as well as in situ pre-sputtering of the GaAs surface with low-energy Ar ions prior to thermal deposition, shows that strong adhesion can be achieved without resorting to chemical cleaning. The substrate temperature and the relative flux of Ar ions to incident Au atoms were varied in order to correlate these parameters with film adhesion. The interfaces of films processed under these various conditions were examined by XTEM, RBS and XPS. Orientation texture was studied by x-ray diffraction (XRD).
Ar+ Induced Interfacial Mixinc in the Pd/Cu Bilayer System
Authors: Kim H.K. , Song J.H. , Kim S.K. , Jeong K. , Whang C.N. , Smith R.J.
Published: March 2011

Ion beam mixing of a Pd/Cu bilayer is studied using irradiation with 80 keV Ar+ ions at room temperature. RBS analysis shows that intermixing has occurred across the Pd/Cu interface, and that the mixing amount increases with increasing ion dose, which agrees well with a model for radiation enhanced diffusion. It is found that the Cu3Pd phase grows in a layer-by-layer manner.
Lead inclusions in aluminium
Authors: Johnson E. , Gråbaek L. , Bohr J. , Johansen A. , Sarholt-Kristensen L. , Andersen H.H.
Published: March 2011

Ion implantation at room temperature of lead into aluminium leads to spontaneous phase separation and formation of lead precipitates growing topotactically with the matrix. Unlike the highly pressurised (∼ 1–5 GPa) solid inclusions formed after noble gas implantations, the pressure in the lead precipitates is found to be less than 0.12 GPa.

Recently we have observed the intriguing result that the lead inclusions in aluminium exhibit both superheating and supercooling [1]. In this paper we review and elaborate on these results. Small implantation-induced lead precipitates embedded in an aluminium matrix were studied by X-ray diffraction. The (111) Bragg peak originating from the lead crystals was followed during several temperature cycles, from room temperature to 678 K. The melting temperature for bulk lead is 601 K. In the first heating cycle we found a superheating of the lead precipitates of 67 K before melting occurred. During subsequent cooling a supercooling of 21 K below the solidification point of bulk lead was observed. In the subsequent heating cycles this hysteresis at the melting transition was reproducible. The full width of the hysteresis loop slowly decreased to 62 K, while the mean size of the inclusions gradually increased from 14.5 nm to 27 nm. The phenomena of superheating and supercooling are thus most pronounced for the small crystallites. The persistence of the hysteresis loop over successive heating cycles demonstrate that its cause is intrinsic in nature, and it is believed that the superheating originates from the lack of free surfaces of the lead inclusions.
Charge States of Heavy Ions with Energy in the MeV Range in Crystalline Semiconductor Targets
Authors: Mazzone A.M.
Published: March 2011

In this work a formalism for the evaluation of electronic losses of heavy ions with energy of few MeV in crystalline semiconductor targets is presented. The stopping values are used in a Monte Carlo simulation to calculate the ion range in silicon and in gallium arsenide for a random orientation of the target and under channelling conditions.
Internal Blackbody Emission Interferometry for Measurement of Crystallization Kinetics and Optical Properties of Amorphous Si and Ge
Authors: Roth J. A. , Olson G. L.
Published: March 2011

The spectral emissivity of a semi-transparent thin film on a heated substrate varies with film thickness due to optical interference within the layer. This leads to oscillations in the emitted blackbody radiation intensity when the film thickness changes with time. We show how measurements of these oscillations have been used to determine the crystallization kinetics and optical constants of ion-implanted amorphous Si and Ge layers undergoing solid phase epitaxial crystallization. A comparision of emission and reflectivity data illustrates that the emission behavior can be understood in terms of a straightforward optical model.
Focused 0.5 MeV Ion Beam Line with Low Aberration Quadrupole Magnets
Authors: Inoue K. , Takai M. , Ishibashi K. , Kawata Y. , Suzuki N. , Namba S.
Published: March 2011

A microbeam line with precisely designed quadrupole magnets has been developed and installed at the Research Center for Extreme Materials, Osaka University. For the purpose of applying the beam line to microbeam RBS/channeling, the damage in <100>Si due to the irradiation of probe beams was studied as a function of incident ion dose from 1015 to 1018 /cm2 with a flux of 8 × 104 nA/cm2. It was found that the dose for channeling measurements should be less than several 1017 /cm2.
RBS Analysis of Elements in the Fingernai
Authors: Madakson Peter
Published: March 2011

Fingernails from several sources were studied to determine elemental compositions. The common elements were found to be H, C, N, O, Ca and Fe. The elements Si, Bi, S, Mo, Ti, Zn, Pb, P and Nd were found on some of the nails; these are considered to result from environmental contamination, food and water intake. The compositions of H, C, N and O correlate with those in the hemoglobin molecule and, they do not vary significantly with time. This suggests that they are associated with dead blood cells. The other common elements, such as Ca and Fe, show variations in composition with time, probably because their amount in the body is determined by food and water intake. Fingernails from female sources have a higher concentration of Ca than those from male sources. Also, the concentration of Ca is generally higher on the outer than the inner surface of the nail, probably to provide a stronger bony structure and mechanical strength on the outside.
Characterization of Pulsed Laser Beam Mixed AuTe/GaAs Ohmic Contacts
Authors: Wuyts K. , Silverans R.E. , Van Hove M. , Van Hove Van Rossum
Published: March 2011

The formation of pulsed laser processed AuTe/n—GaAs ohmic contacts was investigated using I—V measurements, Rutherford Backscattering, and Mössbauer spectroscopy. Ohmic contact resistances comparable to those of furnace processed AuTe and AuGe/GaAs contacts were measured; however, a much thinner intermixed layer was obtained by the laser processing. No evidence for the formation of a n++—GaAs layer could be derived from the experimental data. The results are more consistent with the model explaining the ohmic conduction mechanism by the formation of a graded heterojunction structure.
Melting of Ion Implanted and Relaxed Amorphous Silicon
Authors: Grimaldi M.G. , Baeri P. , Baratta G.
Published: March 2011

The difference in the melting temperature of ion implanted and relaxed amorphous silicon has been measured. Pulsed laser irradiation (λ=347 nm, τ=30 ns) has been used to induce surface melting in the amorphous layer and time resolved reflectivity to detect the melting onset. The threshold energy density for surface melting in the relaxed amorphous was found 15.9±.3% higher than that in the unrelaxed one. The estimate of the variation of the thermal parameters in amorphous silicon upon relaxation allowed a determination of ΔTM=45±10 K between relaxed and unrelaxed amorphous silicon.
Subnanosecond Time-Resolved Electron Diffraction from Thin Crystalline Gold Films
Authors: Chen Hsiu-Cheng , Mourou Gerard A. , Knox Robert S.
Published: March 2011

A 100-ps-resolution electron pulse was used to study a 25-nm thick gold single crystal irradiated by a synchronized infrared optical pulse. The change in electron diffraction intensity following laser heating (the Debye-Waller effect) was measured as a function of delay time. The relaxation of a crystal lattice distortion in the surface region appears to explain an observed oscillation in time of the scattered electron intensity. This novel technique provides a sensitive structure probe for short-time dynamics and is, we believe, the fastest lattice temperature probe.
Parametric Study of Zone-Melting-Recrystallization Processing of Silicon on Insulator Structures
Authors: Lipman Joseph , Miaoulis Ioannis N. , Im James S.
Published: March 2011

The effects of four thermal parameters on the temperature distribution during Zone-Melting-Recrystalllzation processing of Slllcon-On-Insulator devices with graphite strip as the heat source were investigated numerically. Results indicate that the convective heat losses, the variability of the thermal conductivity of silicon as a function of temperature, and the multilayer nature of the structure do not affect the temperature distribution significantly. However, the velocity of the graphite strip can significantly affect the temperature distribution. The temperature profile remains the same for graphite strip velocities below 0.03 cm/sec. The relationship between required graphite strip temperature and velocity of the strip for film melting to occur is presented in graphical form.
Effects of Laser Surface Melting on Structure Character and Erosion Resistance of Plasma Sprayed Ceramic Coatings
Authors: Sun Jia-Shu
Published: March 2011

In this work the effects of laser melting on the micro-morphology, structures and solid particle erosion behaviors of plasma spray alumina, alumina-titania and zirconia coatings have been studied. The results have indicated that laser melting has modified the micro-mophologies and structures of coatings, eliminated the porosity of sprayed coatings and increased the erosion resistance of ceramic coatings. The erosion mechanisms of ceramic coatings have been investigated.
Crystalline Polyimide Thin Film Deposition by Ionized Cluster Bean
Authors: Cho S.J. , Choe H.S. , Jang H.G. , Iim S.S. , Whang C.N.
Published: March 2011

Polyimide thin films are deposited by the ionized cluster beam deposition( ICBD ) technique. Polymerization and crystallization of polyimide were investigated using TEN, IR, and the electronic structure of the polyimide film was investigated using XPS. Films deposited at optimum ion acceleration voltage showed strong preferential crystal orientation. Crystalline polyimide film was obtained at ion acceleration voltage of 700 V.
Ion Beam Modification of High-Tc Superconductors
Authors: Meyer O. , Geerk J. , Kroner T. , Li Q. , Linker G. , Strehlau B. , Xi X.X.
Published: March 2011

Ion irradiation and implantation experiments of high temperature superconductors (HTSC) thin films resulted in many interesting effects. Among those are: (i) the superlinear increase of the resistivity, p, with ion fluence, φ, leading to a metal to insulator transformation, (ii) the large recovery above 150 K of the radiation induced changes of ρ and Tc observed in low temperature irradiation experiments, and (iii) the large structural changes such as the increase of the c-axis lattice parameter with φ, the radiation induced orthorhombic to tetragonal phase transition, and the amorphization. Displaced oxygen atoms play an important role for the observed property changes.
The Importance of Self-Sputtering by Low Energy Ions in Partially Ionized Beam Deposition
Authors: Bai P. , SteinbrÜChel CH. , Lu T.-M.
Published: March 2011

In ion-assisted deposition techniques such as partially ionized beam deposition, ions derived from the depositing material itself concurrently bombard the surface during thin film growth. The ion percentage in the deposition beam ranges from less than 0.1% to 100% (Ion Beam Deposition) with the ion energy varying between a few eV and several keV. When the sputtering yield of the self-sputtering is greater than one, there is a critical ion percentage, for a given ion energy, above which no net deposition can be obtained. The self-sputtering yield is shown to have a square root dependence on the ion energy above the threshold energy by fitting the experimental data obtained from the literature. The critical ion percentage for Al, Cu, Au, Ag, and C is then calculated and plotted as a function of the ion energy so that deposition and no-deposition regions are illustrated in terms of the ion energy and ion percentage.
Electron Beam Induced Oxygen Disordering in Yba2cu307-X Superconductors
Authors: Basu S. N. , Roy T. , Mitchell T. E. , Nastasi M.
Published: March 2011

Thin foils of bulk YBa2Cu3O7–x (YBCO) superconductors were subjected to electron irradiation in a Transmission Electron Microscope (TEM). The resulting disordering of the oxygen atoms and vacancies in the Cu-0 planes was monitored by measuring the splitting of the (110) diffraction spots in the [001] diffraction pattern. Samples were irradiated at 83K with 100, 150, 200 and 300kV electrons. The 100kV electrons did not cause any disordering, even after prolonged irradiation. The results of the higher energy irradiations showed an excellent fit to a disordering model, indicating a lack of radiation assisted reordering at 83K. This was further confirmed by the insensitivity of the disordering to the dose rate of 300kV electrons at 83K. However, at 300K, an increase in the dose rate of 300kV electrons increased the disordering rate, indicating that radiation assisted reordering was occuring at that temperature.
In-Situ Study of Radiation Damage in V2os Induced by Low Energy Electrons
Authors: Ai R. , Fan H.-J. , Stair P.C. , Marks L.D.
Published: March 2011

Radiation damage in V2Os induced by electrons in the energy range 0-3 keV has been studied by high resolution electron microscopy, X-ray photoelectron spectroscopy and mass spectrometry. Different phase transformations were observed when V205 was irradiated by electrons of different energies. The damage kinetics and the role of electron radiation enhanced diffusion were investigated. It was found that nucleation and growth of lower oxides was driven by electron radiation enhanced diffusion.
Dopant Site Location in Dual-Implanted Gap using {111} Planar Channeling
Authors: Parikh N.R. , Kao C.T. , Lee D.R. , Muse J. , Swanson M. L. , Haynes T.E. , Venkatasubramanian R. , Timmons M.
Published: March 2011

Previous studies have indicated that dual implantation can efficiently introduce group IV dopant onto selected sub-lattice sites in m-V compound semiconductors, thus enhancing electrical activation. We studied this phenomenon in GaP using Rutherford Backscattering Spectroscopy (RBS) to determine the lattice location of Sn atoms. We used single crystals of GaP (100) which had been implanted at 400° C with120 Sn+ following previously implanted69 Ga+ or 31P+. Energies were selected for euivalent projected ranges, and all species were implanted with doses of 1 × 1015 atoms/cm2 . Asymmetry in the angular scan of the {111} planar channel was then used to determine the sub-lattice location of the implanted Sn. RBS results indicated that for all implants Sn atoms were substituting Ga and P sites eually. However, Hall effect measurements gave p type conduction for GaP implanted with Sn alone, while those with prior implants of Ga or P resulted in n-type conduction. RBS and Hall effect results are explained by a vacancy complex model.
Low-Energy Implantation of Si and Sn into GaAs
Authors: Rubart W.S. , Jones K.S. , Seiberling L. , Sadana D.K.
Published: March 2011

(100) GaAs was implanted with 29Si+ at energies of 10keV or 20keV and 119Sn+ at an energy of 60keV. The doses used for the Si+ implants were from 1 × 1013 crrr2 to 1 × 1016 cm-2, whereas the Sn+ doses ranged from 1.5×1012 cm-2 to 1.5×1015 cm-2. Implanted samples were rapidly thermal annealed (RTA) in either an argon or arsine ambient at 950°C or 900°C for 12 seconds. Transmission electron microscopy (TEM) results indicate that the annealing ambient has a dramatic effect on the defect annealing kinetics for 10keV implants but not the 20keV Si+ implants. For the 10keV implants reducing arsenic loss via use of an arsine ambient or a Si3N4 cap results in a dramatic decrease in the dislocation loop density. The defect morphology is not related to the as implanted morphology (amorphous or crystalline) but is related to the species. Hall effect measurements revealed an increase in the mobility by a factor of 1.5 times for high dose Si+ and Sn+ implanted samples when RTA was carried out in an arsine instead of an argon ambient. This is despite little or no change in the extended defect morphology or carrier concentration, indicating that the point defect concentration influences the mobility.
Density Measurements of Ion Implanted Amorphous Silicon
Authors: Custer J. S. , Thompson Michael O. , Jacobson D. C. , Poate J. M. , Roorda S. , Sinke W. C. , Spaepen F.
Published: March 2011

The density of amorphous Si was measured. Continuous and buried amorphous Si films were produced by 0.5-8 MeV Si implantation through a steel contact mask. Surface steps of amorphous Si stripes with initial thicknesses from 0.9 to ∼ 5.0 μm were measured using a surface profilometer. For implants up to 5 MeV, the amorphous Si is constrained laterally by the surrounding crystal and deforms plastically. The density of amorphous Si deduced from the surface step heights is 4.91 × 1022 cm-3, 1.7 ± 0.1 % less than the density of crystal Si (5.00 × 1022 cm-3).
Avoiding Transient Diffusion of Boron in Si(100)
Authors: Schreutelkamp R.J. , Lu W.X. , Saris F.W. , Janssen K.T.F. , Ottenheim J.J.M. , Kaim R.E. , Westendorp J.F.M.
Published: March 2011

The diffusion of boron ions implanted in Si(100) during high temperature treatment has been studied by means of Secondary Ion Mass Spectrometry. The boron ions were implanted at energies of 5 and 10 keV along random direction and along [100]. The implantation dose amounted to 1×1013/cm2. During annealing an enhanced diffusion of boron is observed in the tail region of the implantation profiles. In all cases the enhanced diffusion is completed after Rapid Thermal Annealing at 900°Cfor 10”. The enhanced diffusion is largest for the channeled ion implantations. Channeling analysis shows that the transient diffusion is not correlated with the annihilation of defects near the projected range. Therefore, the observed diffusion tail is attributed to rapidly diffusing interstitial boron. Post-amorphization of boron implanted silicon with Si+ ions is used to prevent transient diffusion. Thus a very sharp pn-junction is obtained at a depth of 03 jim and the effective number of charge carriers equals the implanted dose after annealing at 550°Cfor 5hrs and 1000°Cfor 10”.
Characteristics of Metal/P+-Gaas Schottky Barrier Junction Formed by Focused-Ion-Beam Implantation
Authors: Watanabe N. , Tsukamoto T. , Okunuki M.
Published: March 2011

Beryllium (Be) depth profiles, carrier profiles, ideality factors (deviation from thermionic emission and diffusion theory) and Schottky barrier heights of Al/p+-GaAs Schottky diodes were investigated by using focused ion beam (FIB) and de-focused ion beam (DFIB) of 40keV Be+, with dose range from 5.0×1012ions/cm2 to 3.4×1014ions/cm2. Differences of the depth profiles between FIB implantation and DFIB implantation were observed, and it was confirmed that depth profiles of the ion implantations were affected by current densities of the ion probes. The other side, it was recognized that the ideality factors and the Schottky barrier heights of the Schottky diodes were depended on effect of thermionic field emission.
Rapid Thermal Annealing of Si+ and P+ Dually Implanted InP
Authors: Honglie Shen , Genqing Yang , Zuyao Zhou , Shichang Zou
Published: March 2011

150keV Si* ions and 160keV P* ions were implanted at 200°C with doses ranging from 5x1013 to 1x1015/cm2 to study the effect of dual implantations on the electrical properties of Fe doped InP. Samples encapsulated with Si3N4 films of about 1000Å were annealed in a halogen tungsten lamp RTA system under flowing N2 at different temperatures from 700 to 900°C for 5s. It has been found that Si*+P* dual implantations into InP can result in an enhanced activation, particularly significant at high dose of implantation. The maximum dopant activation and average electron mobility for Si*+P* dual implants at a dose of 1×1015/cm2 are 70% and 750cm2/vs, which corresponds to a peak electron concentration of 5×1019/cm3 while that for Si* single implant at the same dose are 29% and 870cm2/vs, which corresponds to a peak electron concentration of 1.2×10 19/cm3. The improvement of the electrical properties is discussed in terms of amphoteric behavior of silicon in InP.
Oxidation Behavior of Pure Titanium Surfaces Coated with Boron Compounds
Authors: Elena M. , Guzman L.A. , Tomasi A. , Gialanella S. , Scardi P.
Published: March 2011

Boron nitride and titanium-boron multilayers (some of which were implanted with nitrogen- or argon ions) have been deposited on pure titanium substrates with an RF sputtering technique. The high temperature (850 °C) behavior of these samples in an oxidizing atmosphere has been studied. While the boron nitride coatings decompose rapidly, with boron diffusing to the surface, an important role for nitrogen has been evidenced. The concentration of nitrogen found at the interface, forming a diffusion barrier, can account for a certain degree of protection.
Martensitic transformations in ion implanted stainless steels
Authors: Johnson Erik
Published: March 2011

Using ion implantation it is possible to induce a variety of phase transformations in the surfaces of stainless steels. The implanted layer can be either amorphized, undergo an fee (γ) => bec (α') martensitic transformation, or compounds can be formed between implanted atoms and target atoms. Stress provides a dominant contribution to the driving forces for amorphization and martensitic transformations. Implantation-induced alloying is important for obtaining the right composition in the implanted layer, whereby the transformation conditions can be optimized. Amorphization is best achieved by implantation of metalloids or other conventionally known glass forming elements. Martensitic transformations in austenitic steels are most easily induced after implantations with noble gases — including helium, where highly pressurized noble gas inclusions are formed. Implantations at high fluences with compound forming species such as nitrogen, boron or phosphorus, will often produce an implanted layer with a structure resembling a ceramic glazing which, depending on the implant species, will be amorphous or crystalline.

In order to understand and predict changes in the surface properties of implanted stainless steels, a detailed knowledge of the implantation induced microstructures is essential. The implanted surface will often have a multiphase structure giving only moderate improvements in corrosion properties, and in particular, resistance to pitting corrosion will often be reduced or only slightly improved. Surface hardness will, on the other hand, in many cases be increased, and large improvements will often be observed in wear and friction properties of the implanted surfaces. Under conditions where formation of a homogeneous surface layer is facilitated, the fatique life of implanted samples may also be extended.
Hardness-Damage Correlations in Ta Implanted Single Crystal Ni3Al
Authors: Was Gary S. , Mantl Siegfried , Oliver Warren
Published: March 2011

Implantation of Ta into single crystal Ni3Al was conducted to determine whether this would be an effective means of producing surface hardening in monolithic alloys. Ta was implanted at 400 keV to doses of 0.7, 3.6 and 25.2 × 1015 cm2 along the <100> axis of a <100> crystal of Ni3A1 at room temperature. Composition vs depth profiles were determined by RBS and lattice location of Ta was determined by channeling angular yield scans about the <100> axis. The hardness of the surface was measured by ultra-low load indentation. Results show that implantation softens the surface and that the Ta is randomly distributed between Ni and A1 sites. Annealing at 1000°C/1h significantly reduces the damage and causes preferential occupation of A1 sites by Ta. It also results in a slight increase in surface hardness. Further annealing at 1200°C/0.25 h increases the surface hardness substantially. The results indicate that the as-implanted surface is softened by disordering and subsequent diffusion of Ta to A1 sites causes hardening of the surface.
Ion Beam Induced Conductivity Changes in Glassy Carbon
Authors: McCulloch D. , Prawer S.
Published: March 2011

Ion beam irradiation of Glassy Carbon is shown to increase its resistivity by up to eight orders of magnitude. These changes in resistivity are correlated with results obtained from Raman spectroscopy and Reflection High Energy Electron Diffraction. At high doses of C implantation there is convincing evidence that ion beam irradiation partially graphitizes the surface of Glassy Carbon.