bluuebunny/crossref_metadata_2025 huggingface dataset:
Stresses in Thin Film Multilayer Interconnect Structures
Authors: Bruck S. M. , Knorr D. B.
Published: March 2011

The difference in coefficient of thermal expansion (CTE) between substrate, polymer, and metal leads to complicated stress fields in multilevel interconnect structures that can potentially compromise reliability. This study uses a materials set representative of the General Electric High Density Interconnect (HDI) multichip module technology to monitor the stress level in the thin film layers of metal and polymer. A Kapton HN® film is bonded to a substrate with heat and pressure using a thin layer of Ultem 1000® thermoplastic as an adhesive. Mechanical test structures consist of single or multilayer thin films fabricated on oxidized silicon or alumina substrates. Layers consist of Ultem, Ultem/Kapton, metal (Ti/Cu/Ti), and Ultem/Kapton/metal. The composite stress due to fabrication and thermal cycling between ambient and 275°C is determined by substrate deflection. The initial stress in the polymer materials is due to the thermal excursion during fabrication. Initial metal stress is intrinsic but becomes extrinsic upon thermal cycling. The composite stress in multilayer structures shows a contribution from each individual layer. The relatively low processing temperature minimizes the magnitude of the stress.
Characterization of Fluorinated Polyimide Films
Authors: Nagarkar Pradnya V. , Lu Jiong Ping , Volfson David , Jensen Klavs F. , Senturia Stephen D.
Published: March 2011

X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) have been used to characterize the polyimide film based on 4,4′ hexafluoro-isopropylidene -bis pthalic anhydride (HFDA) and 4,4′ -bis (4-aminophenoxy) biphenyl (APBP). Films of varying thicknesses made from diluted precursors were studied by IR and XPS. An elemental analysis and a tentative peak assignment for C 1s in XPS is presented. The HFDA-APBP thick films are stoichiometric in composition and binding energies are in good agreement with data on hexafluorodianhydride-oxydianiline (HFDA-ODA). For thinner films, certain chemical modifications were observed at high cure temperatures.
Formation Kinetics and Thin Film Stress of Tin Containing Intermetallic Compounds
Authors: Chan Chin-Jong , Chang Jei-Wei , Chin Leo A.
Published: March 2011

Thin film reactions and its influence on mechanical stress have been investigated in Cr/Cu/Sn and Cr/Ni/Sn multilayer structures. Thin film stresses of different intermetallic compounds in each material system were evaluated using substrate bending technique. Stress state in the thin film structures was round directly related to formation kinetics and thermal properties of intermetallics. In Cu-Sn system, a large internal stress increase in tension was generally observed after being heat treated at high temperatures. In Ni-Sn systems, formation of intermetallics is a relatively slow reaction at elevated temperatures as compared to that of Cu-Sn samples. Contrary to that of Cu-Sn system, formation of Ni-Sn intermetallics causes a decrease in stress in the thin film structure. The correlation of thin film stress state and the structure evolution at the interface is studied and discussed in details.
Development of New Polymeric Materials for Linear Waveguides
Authors: Kim H. K. , Kahn S. , Mates T. , Barclay G. , Ober C. K.
Published: March 2011

We have evaluated the use of either poly(phenylene) prepared via spin-coatable polymeric precursors or fluorinated polysilynes for optical waveguides. Poly(phenylene) precursors were converted into poly(phenylene) by either curing at 300 °C or by deep-UV exposure in the presence of a photoacid generator. The poly(phenylene)s have a number of desirable properties for optical waveguide applications including good near IR transmission, low dielectric constant, thermal and environmental stability and ease of pattern fabrication using microlithographic techniques. Copolysilynes were spin-coated onto various types of substrates and then exposed by deep-UV radiation. Upon exposure of deep UV irradiation in the presence of air, they undergo photooxidative crosslinking to give insoluble glass-like materials. This photo-oxidation process is accompanied by a large decrease in refractive index from n=1.61 to n= 1.485. The photooxidation results suggest that their potential applications are as photoresists and optical waveguides.
Stress Measurement Using a Bilayer Metal-Ceramic Strip
Authors: Kapur Shukla , Flaltz Philip L.
Published: March 2011

Residual stresses that develop in metal/ceramic bonded systems due to thermal expansion mismatch have been calculated using finite element modelling and measured experimentally using a simple bilayer strip. Bending in the strip occurs during cooling due to the stress asymmetry. Residual stresses are calculated by measuring the deflection of the strip and the temperature at which the strip is flat. Various compositions of both copper and nickel pastes, with and without glass and other second phase additions were evaluated on glass-ceramic. The effects of further processes, e.g. thermal cycling, brazing and plating, are also reported in this work.
The use of Microindentations to Measure the Mechanical Protection Provided by Polymeric I.C. Buffer Coatings
Authors: Gealer C.A. , Jeng Y.H. , Sundahl R.C. , Kinsman K.R. , Gaudette J.M.
Published: March 2011

A technique combining the use of microhardness indentations and an aluminum etch decoration process has been developed to measure the relative ability of polymer coatings to protect an integrated circuit (I.C.) device surface from mechanical damage. A threshold for inducing a crack in a passivated silicon surface was measured by applying a grid of indentation loads and measuring the load at which the aluminum etchant revealed damage in the passivation. A polyimidesiloxane and two polyimide materials, with widely different elastic moduli, were tested.

The ability of a coating to protect the chip surface was found to increase with increasing compliance of the film. The materials with the higher threshold loads had lower elastic moduli and allowed greater indenter penetration depth for a given load. Our finite element mechanical model supports the hypothesis that the stress generated by the indenter tip is absorbed and distributed by the lower modulus materials. The stress is transferred to the passivated silicon in the case of the higher modulus film, leading to damage at lower loads.
Area Array Solder Joints for Passive Alignment
Authors: McGroarty John , Yost Boris , Børgesen Peter , Li Che-Yu
Published: March 2011

Passive alignment techniques using area array solder joints are currently under investigation as a cost effective method of achieving electro-optical interconnects in electronic packages. Several investigators have developed models that describe the shapes of and forces produced by the liquid solder drops during reflow. These models are reviewed to provide a scientific basis for the application of such techniques.
Polymeric Materials Requirements for the GE High-Density Interconnect Process
Authors: Cole H.S. , Gorowitz B. , Gorczyca T. , Wojnarowski R. , Lupinski J.
Published: March 2011

In the GE High-Density Interconnect Process, thermoplastic polyetherimide adhesives with selectively variable glass transition temperatures (Tg's) are used as chip attach and overlay adhesive. Alternating layers of patterned metal and dielectric are then applied to fabricate the interconnect structure. Upper layer dielectrics are formed using a modified siloxane-polyimide that can be processed at temperatures below 200 °C. The unique materials requirements and materials development issues associated with this approach are discussed.
Strength Loss in Recycled Fibers and Methods of Restoration
Authors: Minor James L. , Atalla Rajai H.
Published: March 2011

The reduced interfiber bonding capability and reduced conformability of recycled fibers compared to virgin wood pulp fibers is caused by the drying phase of the first papermaking cycle. Changes in the fiber result in stiffness. This effect is more pronounced in chemical pulps than in high lignin content mechanical pulps. This chapter describes methods for restoring some or all the interfiber bonding. In an attempt to develop a “dry” newspaper recycling process, the water-intensive repulping and paper-forming steps were replaced with dry-fiberizing, air-forming, gas-phase ozone and ammonia treatments, and pressdrying. The tensile strength of the dry-recycled paper approached that of the original newsprint.
Old Newspapers: Opportunities and Challenges in Using a Fiber Resource
Authors: Cunningham H. Wilson
Published: March 2011

Newsprint represents a readily identifiable and valuable fiber source. Although the use of old newspapers fibers to make new newsprint is increasing, this activity must compete with the export market and other established usages like paperboard, insulation and speciality product manufacturing.
Ink and Speck Dispersion and Removal
Authors: Doshi Mahendra R. , Klungness John H.
Published: March 2011

Advances in printing technology have posted serious problems for the deinking industry. When ink is fused, as in laser printing and the photocopy process, when water resistant binders are included in coatings or ink formulations, and when varnishes are applied to printed papers, conventional methods fail to disperse inks and specks. The objective of this article is to review different approaches available for removing these inks and specks. Copying processes, coatings, and varnishing processes are discussed prior to discussing deinking and speck removal processes.

Deinking ideally involves intense mechanical, chemical, and thermal action needed to detach non-dispersible inks from fibers. The detached ink is then removed by screens, cleaners, washing, and the flotation process. If higher brightness and cleanliness are desired, high-consistency dispersion, together with bleaching or the use of agglomerating chemicals (for photocopy-laser toners), may have to be considered. For coating specks, increasing the pH. increased pulping time, and removal by cleaners are typically used to reduce the number and size of specks. Varnish specks can be more difficult to remove than coating specks, as they are resistant to chemical treatment and are not easily removed by centrifugal cleaners. Flotation removal holds promise for removing varnish specks if particle size is controlled.
Dry-Process Hardboards from Recycled Newsprint Paper Fibers
Authors: Krzysik Andrzej M. , Youngquist John A. , Muehl James M. , Rowell Roger M. , Chow Poo , Shook Steven R.
Published: March 2011

Dry-process hardboard represents a favorable option for recycling old newspaper fibers. However, dry-process boards tend to be less dimensionally stable than boards processed by other methods. Our objective was to determine the effects of various wood fiber (WF) to old newspaper (ONP) ratios (100:0, 50:50, and 0:100 WF/ONP) on the mechanical strength and water resistance of dry-process hardboards made from these fibers. Untreated and acetylated hardboards were made with 3 or 7 percent resin and 0.5 percent wax. Boards were tested for static bending and tensile strength properties and water resistance. As expected, increasing the resin level from 3 to 7 percent generally improved all measured properties. Acetylation substantially improved the water resistance of all boards; increasing the amount of ONP caused a corresponding deterioration in both mechanical properties and water resistance.
Compatibilization of Biomass Fibers with Hydrophobic Materials
Authors: Krishnan Mohan , Narayan Ramani
Published: March 2011

Composites of biomass fibers with hydrophobic polymers like polypropylene (PP) represent material systems with poor or no interfacial adhesion because of the inherent incompatibility between the respective components. Block and graft copolymers can function as compatibilizers to improve interfacial adhesion and provide composites with an improved and unique balance of properties. Various approaches to improving interfacial adhesion with an emphasis on our work on the compatibilization of biofibers (lignocellulosics) with polypropylene is presented. The biofiber-reinforced polypropylene composite was prepared by reactive extrusion. The compatibilizer which is the graft copolymer produced by reaction of maleated polypropylene with the cellulosic component of the biofiber, was generated insitu during reactive extrusion processing. Maleated polypropylene (MAPP) was produced by the peroxide catalyzed grafting of maleic anhydride (MA) on polypropylene (PP) in the extruder. It was subsequently alloyed with the biofiber by use of a catalyst to form covalent bonds between the components. Alternatively, all the processing steps i.e. maleation, graft formation and the alloying were done in a single extruder run. The chemistry occurring during the two reactive extrusion processing modes and its effect on the properties of the resultant materials is discussed.
Comparative Studies of Ancient Mortars From Giza, Egypt, and Nevali ÇOri, Turkey
Authors: Reller A. , Wilde P.-M. , Wiedemann H.G. , Hauptmann H. , Bonani G.
Published: March 2011

Mortars collected from the Cheops pyramid, the Sphinx and the Chephren pyramid, all at Giza, Egypt, have been compared with recently found mortars of a cult building of the aceramic neolithic at Nevali üori (south east of Urfa, province Hilvan, Turkey), probably one of the earliest sites of civilization. As methods of investigation thermal analysis, X-ray diffraction as well as analytical scanning and transmission electron microscopy have been used. The egyptian mortars have been found to be primarily made up of gypsum, anhydrite and calcite. The comparative results with mortar of the recently detected temple site at Nevali Con, Turkey, give evidence that the burning or otherwise chemical treatment of limestone as crucial ingredient for the fabrication of mortar has been performed at a very early period (10'000 - 8000 B.C.). In order to further confirm the described findings 14C dating measurements have been carried out. The results of the described studies raise many questions concerning early civilizations and their knowledge of technologies as well as the transfer mechanisms of this knowledge.
Theories of Corrosion as Applied to Preservation of Archaeological Ceramics
Authors: Schulz R.L. , Clark D.E. , Folz D.C.
Published: March 2011

An understanding of corrosion processes is beneficial in the preservation of ancient ceramic artifacts. A wealth of information is available on this topic in the materials science and engineering literature. Significant contributions to the corrosion literature have been made over the last 15 years due to the extensive research performed on nuclear wasteform systems. This paper will review the current state of understanding of aqueous corrosion of glasses. We will discuss how this information can be applied to some of the current issues in preservation of archaeological ceramics.
The Consolidation and Desalination of Ceramic Impregnated with Sodium Sulphate
Authors: Paterakis Alice B.
Published: March 2011

A calcareous and non-calcareous clay were fired to 900 degrees Celsius and subsequently impregnated with a solution of Na2SO4. These test samples were then impregnated with one of three consolidants: Acryloid B72, Tetraethyl Orthosilicate (TEOS), Methyl Triethoxysilane (MTS). Desalination tests using the static immersion and stirred solution methods were made to determine the effect of consolidation on the rate and extent of salt extraction. Desalination was monitored by Ionic Conductivity, Atomic Emission Spectroscopy and Ion Chromatography analysis of the extraction solutions.
A Strategy for Planning and Protecting Immovable Heritage: Lessons From Natural Disaster Planning
Authors: Thiel Charles C.
Published: March 2011

Immovable cultural properties, whether buildings, archeological sites, museums or libraries, are at substantial risk in the event of armed conflict. In many ways, natural disasters pose many of the same threats to such structures as does war. Earthquakes impose horizontal loads on structures, their weak direction, tornadoes and hurricanes impose large substantial over pressures on walls and roves, just as ground shock and air blast from explosions do. Fire spreads when there is both fuel and ignition, regardless of whether the ignition is purposeful or accidental. A clear message from the natural hazards literature is that you cannot do anything during the emergency period that you have not carefully thought through before the emergency. This paper reviews approaches to protection of cultural properties and the existing Hague Convention. It is proposed that a concerted effort be mounted by the professional conservation community to: 1) prepare guides on how to identify and document cultural properties important to the community; 2) descriptive manuals on how to protect cultural properties using easily available materials and techniques; 3) distributed them to the local communities likely to be impacted; and 4) provide limited technical resource teams to stabilize or repair after hostilities.
Rock Varnish Cation-Ratios May not be a Reliable Method for Dating Lithic Artifacts
Authors: Bierman Paul , Harry Karen
Published: March 2011

Previous research suggested that the chemical composition of rock varnish, a micrometer thick Si/AI/Mn/Fe coating, changed predictably through time and so could be used as a chronometer. In particular, the cation ratio, (Ca+K)/Ti, was posited to decrease as the varnish aged. However, many earlier varnish studies were not well documented and were based on chemical analyses now shown to be inaccurate. This paper describes a test and the first direct comparison between two different analytic methods used previously to “cation-ratio date” archeologic and geologic materials. It provides methodology sufficiently detailed for replication of analytical and sampling techniques.

Our analyses of rock varnish from a prehistoric chert quarry in California show that the two principal methods used to “cation-ratio date” rock varnish generate consistently different elemental abundances and are therefore not comparable. Neither analytic method produced a significant time-dependent trend in varnish chemistry, suggesting rock varnish cation ratios are not a reproducible and thus probably not a reliable way to date lithic artifacts.
Chinese Budhi ST Brconzes in the Freer Gallery of Art: Physical Features and Elemental Composition
Authors: Eit Paul J , Douglas Janet G.
Published: March 2011

Technical studies were performed on one hundred and seven Chinese copper-alloy sculptures dating from the fifth to the nineteenth centuries A. D. in the collection of the Freer Gallery of Art. X-radiography, stereomicroscopy and metallography were used to determine various physical features; atomic absorption spectroscopy was used to characterize the metal composition. All sculptures were determined to be cast by the lost wax method, and details were tooled by engraving and chasing. Metallographic examination and microprobe analysis showed that the gilding technique used was mercury gilding. Bronzes from the Northern Wei to the Song dynasty are similar in their physical characteristics and alloy type, leaded tin bronze. Beginning in the Ming dynasty, an increase in the amount of zinc is found, both as an impurity in tin bronzes and as a brass alloy constituent.
The Effects of Temperature and Relative Humidity on the Mechanical Properties of Modern Painting Materials
Authors: Erlebacher Jonah D. , Brown Eric , Mecklenburg Marion F. , Tumosa Charles S.
Published: March 2011

The mechanical properties of strength, modulus, and elongation to break were studied for artists' acrylic and alkyd paints under varying conditions of temperature and relative humidity (RH). In the ambient environment, 23° C, 50% RH, acrylic paints are very flexible and are able to sustain large deformations (>50%). Alkyd paints are much stiffer and stronger, and they cannot sustain deformations nearly as dramatic as the acrylics. Acrylic paints at 5% RH are stiffer and stronger than at 50% RH and their ability to stretch is lessened. At temperatures below 15° C at 50% RH, the strength and stiffness of acrylic paints begin to rise rapidly. Some were found to be brittle at 5° C, and by −3° C, all were brittle. At a lower RH, some acrylic paints became brittle at a temperature near 11° C. These temperatures and relative humidities may be found in the transport environment of art objects, and may render them subject to possible damage.
The Moisture Buffering Capability of Museum Cases
Authors: Daniel Vinod , Maekawa Shin
Published: March 2011

Hygrometric half-lives and air exchange rates of four commonly used types of museum cases: Solander boxes, portfolio boxes, music boxes, and document boxes were measured. This paper will present the experimental results and illustrate the effect of the construction materials and closure characteristics on the moisture buffering capability of museum cases.
Analysis of Use Wear on Ceramic Potter's Tools
Authors: Henrickson Robert C.
Published: March 2011

Analyses of the distribution and nature of abrasion on ceramic rings from the third millennium B.C. portion of the Godin III pottery assemblage in western Iran (2600-1400 B.C.) indicate that it represents use wear. Residual scars on pottery vessels and reconstruction of vessel forming sequences support identification of these rings as potter's tools. They provide interconnections among varied sizes of Buff Common ware vessels made using different forming and finishing methods. This strengthens the inference of workshop production by specialist potters who make the full range of Buff Common ware vessels.
A New Look at Stone Drills of the Indus Valley Tradition
Authors: Kenoyer J. Mark , Vidale Massimo
Published: March 2011

Drilling technology of the Indus Valley Tradition was highly specialized and various types of chert and jasper were used to drill different types of materials. Earlier studies used primarily macroscopic observations to define features such as the manufacturing technique of drills, the raw materials and the mechanics of drilling. These generalizations can be revised given the discovery of important workshop areas and the availability of SEM, XRD and electron microprobe analysis. This paper will summarize the current state of. drilling research and define two categories of drills that were used in antiquity; tapered cylindrical drills and constricted cylindrical drills. Directions for future research on the relationship between drilling and other contemporaneous technologies are discussed.
A Third Millennium B.C. Glazed Quartz Bead From Tell Es-Sweyhat, Syria
Authors: Vandiver Pamela B. , Fenn Mark , Holland T.A.
Published: March 2011

The probable composition of a weathered, blue-green glaze on a ground quartz bead was reconstructed. The bead was excavated from Operation 5 at Tell es-Sweyhat, Syria, in 1991 and is dated to the last quarter of the third millennium B.C. Special sample handling was required by the poor state of preservation of the glaze. Microprobe analyses and replicate melts showed that the composition was 60% SiO2, 20% CuO and 20% flux, probably as soda, potassia or a combination. This composition is unusual for ancient glasses and glazes because of its high copper oxide content, which may indicate a link with copper or malachite technology. Very few glass and glaze compositions are known from the third millennium B.C., and none of these has such a high copper concentration, nor are there examples reported from the mid-second millennium B.C. with one exception of glazed tiles from Kerma in Sudan. This rare and unusual composition suggests that there may have been several paths to the development of glasses and glazes. Some of these paths were successful, and some others, as this one, did not continue and were “dead-end” technologies.
The Roman Ceramics of Salobrena (Granada-Spain) and their Raw Materials
Authors: Andres Ana M De , MuÑOZ Isabel
Published: March 2011

Nineteen roman ceramic sherds found near Salobreña (Granada, Spain), in the western coast of the Mediterranean Sea, as well as different ceramic clays from the surroundingsare studied. Both clays and ceramic sherds are characterizad by X-ray diffraction and spectrometry, differential thermal analysis, and scanning electron and optical microscopies. A good number of the ceramic pieces, among which some “Terrae Sigillatae”, have a composition similar to that of the local clays and, thus, have been probably manufactured at Salobreña. Only a few of them have a foreign origin. For most of them, the firing temperature was about 800-850 °C, although some have been produced at 900-1000 °C, and some others at 1000-1100 °C. It is concluded that Salobreña appearsto have been an important settlement just in the third century of the Christian era.
A Preliminary Scientific Study of Traditional Korean Celadons and their Modern Developments
Authors: Koh Choo C.K.
Published: March 2011

In studying celadons culture of Korea scientifically 81 sherds from nine different kiln sites of different periods are analyzed for their macroscopic, compositional and microstructural characteristics. The raw materials used for modern reproduction are analyzed for their chemical and mineralogical composition and compared with those of traditional pieces.
Archaeological Bitumen: Indentification, Origins and Uses of an Ancient Near Eastern Material
Authors: Connan Jacques , Deschesne Odile
Published: March 2011

Prior to their modern invention, the use of petroleum products (bitumen, asphalt, etc.) was common in the prehistory of the Near East. In Mesopotamia where they are plentiful, often occurring at the surface of the ground, these products have been utilized in diverse ways: for construction and caulking of buildings, as a waterproofing agent, and even as a medicine to remedy coughing. Archaeologists have questioned the location of principal sites exploited in antiquity and the ways that these products have been used. As the result of a close collaboration between petroleum specialists and archaeologists, this article explains how geochemical analysis has enabled identification of the provenance of bitumen utilized at Babylon in Iraq, how the inhabitants of Susa in Iran used bitumen, its preparation and also its fabrication as an artificial material which has proven to be as durable as stone.
Preliminary Technical Study of Medieval Limoges Enamels
Authors: Dandridge Pete , Wypyski Mark T.
Published: March 2011

Enamels from Northern Spain, Central France, and Limoges, dating from the 10th century to the mid 13th century, were analyzed by energy dispersive x-ray spectrometry and x-ray diffractometry to determine their overall compositions, and the opacifiers and colorants used. The compositions suggest the re-use of Roman tesserae. Calcium and lead antimonates were found as the predominant opacifiers; however, tin oxide and lead-tin yellow were also found in some of the enamels, either singly or in combination with the antimonates. One of the enamels from Limoges varied from the others in that the enamels had overall compositions similar to Islamic or Venetian glasses, and contained only tin oxide as an opacifier.
Loss of Infrared Linear Dichroism in Collagen Fibers as a Measure of Deterioration in Skin and Semi-Tanned Leather Artifacts
Authors: Young Gregory S.
Published: March 2011

Polarized radiation is used in a Fourier transform infrared (FTIR) microspectroscopic technique to detect molecular conformational change in collagen fibers resulting from deterioration. Absorbance spectra of single fibers are produced with polarization oriented first parallel (A‖) and then perpendicular (A⊥) to the fiber axis. The amide Ill band (1230- 1300 cm−1) shows strong positive dichroism, with up to six times greater absorbance occurring with parallel polarization. Losses of dichroism result from breakdown in the molecular structure of collagen. Integrations of the amide III bands are used in ratios, A‖/A⊥;, which provide a measure of the degree of molecular order. Ratios for degraded and undegraded material are compared to produce semi-quantitative information about deterioration.
Pore Potential and Durability of Limestone at the Sphinx
Authors: Gauri K.L. , Yerrapragada Srinivas S.
Published: March 2011

In mercury porosimetry of limestone two hystereses are generated. A PV-- diagram for initial intrusion and extrusion reveals one hysteresis as entrapment of mercury in large cavities that are connected to the exterior through narrow channels. The other hysteresis is a loop (HL) enclosed between the extrusion and reintrusion curves which indicate narrow channels. An HL is unique to a stone.

The thermodynamic work (W) calculated as ΣPV, is W1, WE, WRE, WHy, and WT for the initial intrusion, extrusion, reintrusion, the hysteresis loop, and the entrapment, respectively. The pore-potential (U) defined as

regulates the volume and rate of movement of water through the pores which in turn determines the stone's durability. Microporous stones are highly susceptible to weathering and have a large value for WHy. WHy. in association with the WT can be related to the durability factor (DF) as

The DF values, thus obtained, accurately reflect the observed condition of the strata of the Sphinx.
Electron Microscopy Studies of the Chronological Sequences of Teotihuacan Plaster Technique
Authors: Magaloni Diana , Falcon T. , Cama J. , Siegel R. W. , Lee R. , Pancei R. , Banos L. , Castano V
Published: March 2011

Over 108 samples of mural paintings from Teotihuacán, México, were studied by scanning electron microscopy, optical microscopy and X-ray diffractometry. The results show a sequence in the techniques employed to produce the mural painting's supporting plasters -made of lime and different sands. The technical stages found can be used as archaeological data to help understand the continuous evolution of 800-year mural paintings. The consequences of our study are discussed in detail.
Computer Simulation of Scattered Ion and Sputtered Species Effects in Ion Beam Sputter-Deposition of High Temperature Superconducting Thin Films
Authors: Krauss Alan R. , Auclello Orlando
Published: March 2011

Ion beam sputter-deposition is a technique currently used by many groups to produce single and multicomponent thin films. This technique provides several advantages over other deposition methods, which include the capability for yielding higher film density, accurate stoichiometry control, and smooth surfaces. However, the relatively high kinetic energies associated with ion beam sputtering may lead to difficulties if the process is not properly controlled. Computer simulations have been performed to determine net deposition rates, as well as the secondary erosion, lattice damage, and gas implantation in the films, associated with primary ions scattered from elemental Y, Ba and Cu targets used to produce high temperature superconducting Y-Ba-Cu-O films. The simulations were performed using the TRIM code for different ion masses and kinetic energies, and different deposition geometries. Results are presented for primary beams of Ar+, Kr+ and Xe+ incident on Ba and Cu targets at 0° and 45° with respect to the surface normal, with the substrate positioned at 0° and 45°. The calculations indicate that the target composition, mass and kinetic energy of the primary beam, angle of incidence on the target, and position and orientation of the substrate affect the film damage and trapped primary beam gas by up to 5 orders of magnitude.
Fabrication of P-Type Cuinse2 Thin Film by MBD Using ECR Excited Nitrogen Ion Source
Authors: Nishitani M. , Negami T. , Terauchi M. , Wada T. , Hirao T.
Published: March 2011

Polycrystalline CuInSe2 thin films were prepared by coevaporation of the elements under the irradiation of nitrogenions excited by ECR plasma. Nitrogen atoms were doped uniformly in the obtained CuInSe2 films according to the SIMS analysis. The films showed p-type conduction even in the slightly In-rich region where the coevaporation films without the irradiation of nitrogen ions showed n-type conduction. These results show that p-type CuInSe2 thin films even in the slightly In-rich region can be fabricated by the irradiation of ECR excited nitrogen ions during its ternary coevaporation process.
Defect Structure of SiON Films Prepared by ECR Plasma CVD Method
Authors: Izumi T. , Matsumori T. , Kitagawa M. , Hirao T.
Published: March 2011

The defect structure of silicon oxynitride films prepared by the ECR Plasma CVD method have been studied by ESR(electron spin resonance) method. The ESR analysis revealed the presence of three paramagnetic defects,that is, Si dangling bonds(g=2.0055 ΔHpp=8 Oe), Si dangling bonds with N atom neighbors(g=2.004, ΔHpp=12 Oe) and E-center(g=2.0016, ΔHpp=4 Oe). These centers strongly depend on the deposition conditions, such as gas flow rate, and microwave powers. The defect density is minimum for the deposition condition of SiON films, under the gas flow O2 /(N2 +02)ratio of 1/3, gas pressure of 8.3x10−4Torr and microwave power of 50OW.
Compositional Determinations of Oxide-Nitride-Oxide Stacked Dielectric
Authors: Waytena G.L. , Hren J. , Weiss J.K. , Rez P. , Fountain G.G. , Hattangady S.V.
Published: March 2011

Electron holography, and high spatial resolution (17Å) computer controlled Parallel Electron Energy Loss Spectrometry (PEELS) were used to probe the structure of and chemical profile across a thin silicon Oxide-Nitride-Oxide (ONO) layered structure of nominal width 10Å-50Å-10Å. We found that the layer widths are on the average 13Å-28Å-18Å, the first oxide layer was discontinuous, and the second oxide layer contained nitrogen. The nitride layer had a silicon to nitrogen concentration ratio of 1.0 ± 0.1. These results show, for the first time, the power of holography in characterizing thin, light element, amorphous layers and the importance of computer controlled parallel energy loss line scans for obtaining analytical information at the highest spatial resolution with minimum dose.
Low Energy Si Bombardment Effects on Epitaxial Si Growth
Authors: Kitabatake Makoto , Greene J. E.
Published: March 2011

Molecular dynamics simulations were used to follow low-energy ion/surface interactions in Si MBE including kinetic energy redistribution in the lattice as a function of time, projectile and lattice atom trajectories, and the nature, number, and depth of residual defects. The simulations were carried out using the Tersoff many-body potential for Si. Irradiation events were initiated with 10 and 50 eV Si atoms incident normal to the Si(001)2xl surface at an array of points in the primitive surface unit cell. Epitaxy, exchange reactions, and defect (vacancy and interstitial) formations were observed. Quasidynamic simulations suggested that the interstitials preferentially diffuse toward the surface and are annealed out over times corresponding to monolayer deposition at typical Si MBE growth temperatures.
Characterization of In Situ P-Type and N-Type Doped Si and GeXSi1−X Films Grown by Low Temperature Remote Plasma Chemical Vapor Deposition
Authors: Thomas S. , Irby J. , Kinosky D. , Qian R. , Iqbal I. , Mahajan A. , Banerjee S. , Tasch A. , Magee C.
Published: March 2011

Low temperature Si and Si1−xGex epitaxy is one of the major thrusts in the trend towards low temperature Si processing for future generation ULSI circuits and novel Si-based devices. A remote plasma-enhanced chemical vapor deposition (RPCVD) technique has been developed to achieve Si homoepitaxy and Si1−xGex heteroepitaxy at low temperatures (≤450'C). P-type films have been grown by introducing 90 ppm or 5000 ppm B2H6/He into the system during the growth process to achieve in situ electrically active boron doping. A mesa diode structure with minimal thermal budget in the fabrication process has been employed to evaluate the properties of the boron-doped Si and Si1−xGex films grown at 450°C by RPCVD. Leakage current densities are reduced for diodes grown at 14–18 W (40–50 Å/min. growth rates) compared to similar devices grown at 6.6 W (5 Å/min.). N-type films have been grown by the introduction of 50 ppm PH3/He. Secondary ion mass spectroscopy (SIMS) has been employed to analyze the boron and phosphorus incorporation efficiencies and doping profiles under different conditions. Boron and phosphorus doping profile transitions as sharp as 50–100 Å/decade have been achieved. Transmission electron microscopy (TEM) has been used to investigate the microstructure of the B-doped films.
The Role of Ion Beam Assisted Surface Chemistry in Etching: Adsorption and Reactions of ALKYL Halides
Authors: Marshall Duncan , Jackman Richard B.
Published: March 2011

The form of ideal surface chemistry that is necessary for chemically assisted ion beam etching (CAIBE), with particular reference to in-situ processing is considered. Whilst to date CAIBE has been almost exclusively carried out with chlorine, distinct advantages exist if a compound that which displays spontaneous reactivity which is limited to one or two monolayers can be used. The role of alkyl halides in this scenario has been investigated through the use of surface spectroscopic probes to investigate the microscopic chemical and ion beam assisted reactivity that may be achieved. Dichloroethane has been found to display promising behaviour.
Synthesis of Cupric Oxide Films using Mass-Separated Low-Energy O+ Beams
Authors: Kita R. , Hase T. , Itti R. , Sasaki M. , Morishita T.
Published: March 2011

We report the epitaxial growth of CuO thin films prepared by lowenergy and high-density O+ ion beams mass-separated from an oxygen plasma. We have successfully produced O+ beams of 50 μA/cm2 while maintaining an ambient pressure of 3×10−9 Torr during the growth. CuO grows on MgO(100) with epitaxial relationship of (111)CuO // (100)MgO and [110]CuO // [110]MgO at room temperature and even under conditions where the flux density of O+ beams is at least one order of magnitude lower than the minimum flux density of O2 required to form CuO.
Advanced Ion Beam Material Processing Projects in Japan
Authors: Yamada Isao
Published: March 2011

R&D projects of ion beam systems and ion beam process technology have been conducted under the National Research and Development Program known as the “Large-Scale project”. The project includes development of five large-scale ion beam systems and their application for surface modifications. Under another program called the National Research Facility Development Project, the Ion Engineering Center Corporation has been established in order to promote industrial applications of ion beam processes. This paper reviews those projects and recent progress on development of large-scale ion beam systems and related materials processing technology. Major research projects which have been funded by the Ministry of Education for ion beam related researches are also reviewed.
Atomic and Molecular Beam Studies of Etching and Related Surface Chemistries
Authors: Coburn J.W.
Published: March 2011

Results will be presented using a new ultrahigh vacuum system designed to investigate the complex surface chemistries prevailing in plasma-assisted etching processes which use more than one halogen or halogen-hydrogen gas mixtures. In this new apparatus, two separate controllable beams of atoms can be directed onto a surface and energetic ion bombardment of the surface can be introduced. Neutral species evolved or reflected from the surface are monitored with modulated beam mass spectrometry. Etch rates as small as 10−3 Å/sec can be detected. The chemical systems which have been used are Si-F-Cl, Si-F-H and Si-CI-H and some unexpected phenomena observed with these systems will be described. Some catalytic reactions have also been observed with these gases in the presence of polycrystalline Ni and Pd surfaces and another example of an oscillatory surface reaction has been found.
Edge-On Ion Irradiation of Electron Microscope Specimens
Authors: Otero Mauro P. , Allen Charles W.
Published: March 2011

A special technique is described for in situ transmission electron microscope (TEM) experiments involving simultaneous ion irradiation, in which the resultant phenomena are observed as in a cross-section TEM specimen. That is, instead of ion-irradiating the film or foil specimen normal to the major surfaces and observing in plan view (i.e., in the same direction), the specimen is irradiated edge-on (i.e., parallel to the major surfaces) and is observed normal to the depth direction with respect to the irradiation. The results of amorphization of Si, irradiated in this orientation by 1 or 1.5 MeV Kr, are presented and briefly compared with the usual plan view observations. The limitations of the technique are discussed and several experiments which might profitably employ this technique are suggested.
Amorphization of PLZT Material by 1.5 MeV Krypton Ion Irradiation with In Situ TEM Observation
Authors: Wang L.M. , Wu A.Y. , Ewing R.C.
Published: March 2011

PLZT 9/65/35 single crystals were irradiated with 1.5 MeV krypton ions at 25–450°C in the HVEM-Tandem Facility at Argonne National Laboratory. In-situ TEM was performed during irradiation in order to determine the critical amorphization dose. At room temperature, the material was completely amorphized after a dose of only 1.9×1014 ions/cm2, less than one fifth of the critical amorphization dose for silicon (1×1015 ions/cm2). The critical amorphization dose for the PLZT material increased with increasing irradiation temperature. At 450°C, amorphization was not observed after a dose of 1.1×10 15ions/cm2.
Optical Technique for Characterization of High Energy Ion Implanted Materials
Authors: Aizenberg Gustavo E , Swart Pieter L , Lacquet Beatrys M
Published: March 2011

A new method for the characterization of high energy ion-implanted materials has been developed. The refractive index and thickness of the amorphous layer produced by ion-implantation as well as the recrystallized layer formed by annealing of the ionimplanted samples can be determined by means of this non-destructive optical technique.

For frequencies where the carriers do not respond, the measured reflectance is bilinear transformed, and further digital signal processing yields information about thickness and refractive index of the abovementioned layers. When working at optical frequencies where the carriers can respond to the electromagnetic field the physical position of the peak concentration follows directly from the processed reflectance data. Simulated and experimental data have been analyzed. The position of the boundaries between the amorphous, recrystallized and substrate zones, as well as the position of the carrier concentration peak can be determined for various steps of annealing. The algorithm has the advantage of being simple and time efficient.
Radiolytic Modification of Gas Sensor Surface Chemistry
Authors: Sofield C J , Guppy R M , Merdrignac O M , Moseley P T , Moore V J , Peat R
Published: March 2011

The surfaces of thin films of tin dioxide prepared by radio frequency sputtering have been driven to react with nitrogen by exposure to a proton beam in an atmosphere containing nitrogen gas. Such modification of the composition of the free surfaces of the films modifies their gas response characteristics substantially.

The effects of modifying the surface of tin dioxide by exposure to proton beams in air have been demonstrated for thin films prepared both by tputtering and by dip coating with a sol.
The Effect of Atomic Mixing on the Depth Profiles of Metal Markers in Silicon
Authors: King B. V. , Tonn D. G. , Tsong I.S.T. , Leavitt J. A.
Published: March 2011

Atomic mixing effects of sputter depth-profiles are modeled by a diffusion theory with a depth-dependent diffusion constant D. The model is compared to SIMS depth profiles, using 5 keV Ar+ bombardment of dilute thin-film multilayers of Al, Ag, Ti and Mo in silicon. The experimental values of D can be explained by cascade mixing and radiation enhanced diffusion within the cascade for Al, Ag and Ti markers but not for the Mo marker.
Microstructural Developments During Implantation of Metals
Authors: Potter D. I. , Ahmed M. , Lamond S.
Published: March 2011

The chemical and microstructural changes caused by the direct implantation of solutes into metals are examined. The particular case involving Al+-ion implantation into nickel is treated in detail. Chemical composition profiles measured using Auger spectroscopy and Rutherford backscattering, and average near-surface chemical composition measured using an analytical electron microscope, are compared with model calculations. The microstructures that develop during implantation are investigated using transmission electron microscopy. For low fluences implanted near room temperature, these microstructures contain dislocations and dislocation loops. Dislocation loops, dislocations, and voids result from implantations at temperatures near 500°C. Higher fluences at these elevated temperatures produce precipitates when the composition of implanted solute lies in a two-phase region of the phase diagram. Implanted concentrations corresponding to intermetallic compounds produce continuous layers of these compounds. Room temperature, as compared to elevated temperature, implantation may produce the same phases at the appropriate concentrations, e.g. β'-NiAl, or different phases, depending on the relative stability of the phases involved.
The Development of the Amorphous Phase in NiTi During Heavy Ion or Electron Bombardment
Authors: Brimhall J. L. , Kissinger H. E. , Pelton A. R.
Published: March 2011

A supralinear dose dependence for the amorphous transformation was observed in NiTi during bombardment with 2.5 MeV Ni+ ions. These results are consistent with a mechanism that requires cascade overlap to obtain a critical defect density for the amorphous transformation. Direct amorphization in the cascades was not resolvable. The temperature dependence of the minimum dose required for complete amorphous transformation had the same form as that observed for amorphization of silicon. Amorphization caused by electron bombardment required a higher dose than by ion bombardment. Different degrees of homogeneity of the damage state between ions and electrons can explain the dose dependence on particle type.
Hvem and Internal Oxidation Studies of Lithiated Nickel
Authors: Seshan K. , Baldo P. , Wiedersich H.
Published: March 2011

Pure, polycrystalline nickel samples were implanted with lithium to doses up to 5 × 1017 lithium ions per square centimeter, at a temperature of 500°C, such that the implantation damage would anneal. These samples were then prepared for electron microscopy and examined at 1 MeV, in the Argonne National Laboratory HVEM facility. It was observed that compared to pure nickel, the lithium implanted nickel showed a different radiation damage behaviour. A plausible explanation for the difference in behaviour is presented in this paper.

The lithium implanted nickel, in the high dose samples, also showed an unusual form of precipitation. Electron microscopy revealed the precipitates to have truncated octahedral shapes with {111} planes for sides and {100} planes truncating the corners. They resemble voids and helium bubbles in nickel. The precipitates appear to be associated with dislocations. The lithium implanted nickel was internally oxidized in order to obtain evidence for the presence of lithium. Electron diffraction analysis of the internally oxidized lithiated nickel showed the presence of a topo-taxial compound being formed, with an ordered NaCl-structure. Possible interpretations of this diffraction pattern are discussed.
Epitaxial Crystallisation of Doped Amorphous Silicon
Authors: Elliman R.G. , Johnson S.T. , Short K.T. , Williams J.S.
Published: March 2011

This paper outlines a model to account for the influence of doping and electronic processes on the solid phase epitaxial regrowth rate of ion implanted (100) silicon. In addition we present data which illustrates good quality epitaxial crystallisation of silicon at 400°C induced by He+ ion irradiation. We tentatively suggest that electronic energy-loss processes may be responsible for this behaviour.