bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomically Layered Structures for Perpendicular Magnetic Information Storage
Authors: Lairson Bruce M. , Visokay M. R. , Sinclair R. , Brennan S. M. , Clemens B. M. , Perez J. , Baldwin C. 
Published: April 2011

ABSTRACTLayered structures can possess a high volumetric density of interfaces, which can result in novel magnetic properties. We report magnetic characteristics of two types of atomically layered structures, (001) oriented intermetallics with the CuAu(I) crystal structure and (111) oriented artificial multilayers. C-axis oriented superlattices of PtFe, PtCo, PdFe and PdCo with the layered CuAu(I) structure, possess large magnetic anisotropies and novel magneto-optic properties relative to the corresponding random alloys. These films are produced by annealing, with tetragonality and magnetic anisotropy developing in a fashion which depends on the initial bilayer period and annealing parameters. (111) oriented artificially grown Pd/CoCr multilayers are reported for perpendicular magnetic recording applications. Using a perpendicular contact probe transducer, the multilayers exhibit two times the readback signal of CoCr media. The multilayers can be made with low roughness suitable for contact recording, and can generate narrow readback pulses with large amplitude. Many aspects of Pd/Co performance, such as overwrite, can be predictably optimized for a given set of transducer properties. The reported results show that compositionally modulated structures can be made which have a wide variety of useful properties for perpendicular hard disk and magneto-optic recording.
On the Perpendicular Magnetic Anisotropy of Pt/Co Multilayers: Structure-Property Relationships
Authors: Bertero G. A. , Sinclair R. 
Published: April 2011

ABSTRACTA series of Pt/Co multilayers were sputter-deposited under various deposition conditions to promote structural changes resulting in marked differences in both the perpendicular anisotropy and magnetic coercivity. High resolution transmission electron microscopy was used in combination with other analytical techniques to study the structure of these films. It was found that the most important feature controlling the magnitude of the anisotropy is the interface sharpness. Conversely properties such as the quality of the (111) texture, grain shape or the defect structure, were found to be of secondary importance. The magnetic coercivity ranged from 0.6 to 7 kOe depending on the sputtering conditions and was found to depend strongly on the grain boundary structure rather than on the grain size.
Magnetic X-Ray Circular Dichroism in Fe Co Pt Multilayers
Authors: Tobin J. G. , Jankowski A. F. , Waddill G. D. , Sterne P. A. 
Published: April 2011

ABSTRACTMagnetic x-ray circular dichroism in x-ray absorption has been used to investigate the ternary multilayer system, Fe Co Pt. Samples were prepared by planar magnetron sputter deposition and carefully characterized, using a variety of techniques such as grazing-incidence and high-angle x-ray scattering, Auger depth profiling and cross-section transmission electron microscopy. As previously reported, the Fe9.5Å Pt9.5Å exhibits a large dichroism in the Fe 2p absorption. Interestingly while the Co9.5Å Pt9.5Å has no measurable dichroism, the Fe4.7Å Co4.7Å Pt9.5Å sample has a dichroism at both the Fe 2p and Co 2p absorption edges. These and other results will be compared to slab calculation predictions. Possible explanations will be discussed.
Texture and Grain Size of Permalloy Thin Films Sputtered on Silicon With Cr, Ta and SiO2 Buffer Layers
Authors: Galtier P. , Jerome R. , Valet T. 
Published: April 2011

ABSTRACTWe have investigated the structural properties of Ni80Fe20 thin films sputtered on silicon with Cr, Ta and SiO2 buffer layers using transmission electron microscopy. We observe a decrease of the grain size when Ta and SiO2 underlayers are used instead of Cr. Permalloy films deposited on Ta layers are strongly (111) textured while those grown on Cr and SiO2 are mostly randomly oriented. The results are discussed with respect to the nanostructure of both Ta, Cr and SiO2 underlayers and in relation to the variation of the magnetic softness observed in this system.
Microraman Study of PbTiO3 Thin Film Prepared by Sol-Gel Technique
Authors: Ching-Prado E. , Reynés-Figueroa A. , Katiyar R. S. , Majumder S. B. , Agrawal D. C. 
Published: April 2011

ABSTRACTA PbTiO3 thin film prepared on silicon substrate by sol-gel technique has been studied by micro-Raman spectroscopy. The spectra, in comparison to the single crystal work, show high background in the low frequency region and Raman lines are broader, thus revealing the polycrystalline nature of the film. The frequencies of the Raman bands in the film are clearly shifted to lower frequencies compared to the corresponding ones in the single crystal or powder forms. This phenomenon is similar to the hydrostatic pressure effect on the Raman lines of PbTiO3 single crystal. The film, therefore, has grains under stress. This stress is caused by non-equilibrium defects and diffusion at the interface. Measurements at different film positions showed variation in the frequency and width of the Raman bands which are associated with the stress and grain size inhomogeneities. The measured shift in the Raman frequencies suggest grain sizes ≤l μm. XRD indicates grain size around 22 nm.
Micro-Mechanical Characterization of Tantalum Nitride Thin Films on Sapphire Substrates
Authors: Venkataraman Shankar K. , Nelson John C. , Moody Neville R. , Kohlstedt David L. , Gerberich William W. 
Published: April 2011

ABSTRACTThe adhesion of Ta2N thin films – often used as thin film resistors – to sapphire substrates has been studied by continuous microindentation and microscratch techniques. Ta2N films, 0.1-0.63μm in thickness, were sputter deposited onto single crystal substrates. Continuous microscratch experiments were performed by driving a conical diamond indenter simultaneously into and across the film surface until stresses high enough to delaminate the film were developed. Continuous microindentation experiments were performed to induce film spallation by normal indentation. From both of these experiments, interfacial fracture toughness was determined as a function of film thickness. The interfacial fracture toughness obtained from continuous microscratch experiments is 0.53±0.17 MPa√m, independent of film thickness. This observation indicates that there is almost no plastic deformation in the film prior to fracture so that a ‘true’ interfacial fracture toughness is measured. For the 0.63 µm thick film, continuous microindentation data yielded a fracture toughness of 0.61 ±0.08 MPa√m, which matches closely the value obtained from the microscratch test. Hence, the continuous microscratch and microindentation techniques are viable methods for determining the interfacial fracture toughness in such bi-material systems.
Raman Characterization of Polycrystalline Silicon: Stress Profile Measurements
Authors: Benrakkad M. S. , Perez-Rodriguez A. , Jahwari T. , Samitier J. , Lopez-Villegas J. M. , Morante J. R. 
Published: April 2011

ABSTRACTRaman spectroscopy is applied for the analysis of polysilicon films deposited on SiO2 sacrificial layers. Different deposition technologies and processing parameters have been studied. The features of the first order Si Raman signal (shape, width and position of maximum) are analyzed in order to evaluate the stress average value in the scattering volume. MicroRaman measurements performed at different points on the edge of the samples allows the estimation of the stress gradient through the polysilicon layers. These measurements are correlated with the structure obtained by using micromachined test structures.
Tribological Properties of Laser Deposited SiC Coatings
Authors: Zehnder T. , Blatter A. , Burger J. , Julia-Schmutz C. , Christoph R. 
Published: April 2011

ABSTRACTWe studied on a nanometer scale the tribological properties of thin silicon carbide films on Si(100) wafers and stainless steel. The coatings were fabricated from a sintered SiC target by pulsed ArF laser deposition at substrate temperatures between 20 °C and 1000 °C. Amorphous films resulted at low deposition temperatures while nanocrystalline structures developed at high deposition temperatures. An atomic force/lateral force microscope was employed to characterize the film topography and the friction behavior. The microhardness was determined from measurements utilizing a depth-sensing nanoindentation instrument. The SiC films on Si(100) exhibit a smooth surface with an average roughness Ra of a few nanometer, the amorphous films being even an order of magnitude smoother. No appreciable differences were found in microhardness and friction coefficient between amorphous and nanocrystalline films. On stainless steel, amorphous SiC coatings were obtained for deposition temperatures up to 500 °C. Their surface relief portrayed the grain boundaries of the underlying steel substrate, reflecting the ballistic nature of the deposition process. No stoichiometric films were obtained above 500 °C as the silicon from the growing film quickly dissolved in the steel substrate.
Mean Field Analysis of Orientation Selective Grain Growth Driven By Interface-Energy Anisotropy
Authors: Floro J. A. , Thompson C. V. 
Published: April 2011

ABSTRACTAbnormal grain growth is characterized by the lack of a steady state grain size distribution. In extreme cases the size distribution becomes transiently bimodal, with a few grains growing much larger than the average size. This is known as secondary grain growth. In polycrystalline thin films, the surface energy γs and film/substrate interfacial energy γi vary with grain orientation, providing an orientation-selective driving force that can lead to abnormal grain growth. We employ a mean field analysis that incorporates the effect of interface energy anisotropy to predict the evolution of the grain size/orientation distribution. While abnormal grain growth and texture evolution always result when interface energy anisotropy is present, whether secondary grain growth occurs will depend sensitively on the details of the orientation dependence of γi.
Energies and Atomic Structures of Grain Boundaries in Silicon: Comparison Between Tilt and Twist Boundaries
Authors: Kohyama M. , Yamamoto R. , Watanabe Y. 
Published: April 2011

ABSTRACTThe energies and atomic structures of tilt and twist boundaries in Si have been examined by using the tight-binding electronic theory, and the reason why twist boundaries are seldom found in polycrystalline Si has been investigated. About the frequently observed {122} Σ=9 and {255} Σ=27 tilt boundaries, the configurations without any coordination defects consistent with the electron microscopy observations have relatively small interfacial energies with small bond distortions. About the <111> Σ=7, <011> Σ=3 and <001> Σ = 5 twist boundaries, the configurations contain larger bond distortions or more coordination defects, and much larger interfacial energies than those of the tilt boundaries. The <001> twist boundaries have very complex structures as compared with the other twist boundaries, which can be explained by the morphology of the ideal surfaces. The stability of the tilt boundaries in Si can be explained by the viewpoint of the stable structural units consisting of atomic rings.
Polycrystalline Grain Structure of Sputtered Aluminum Nitride Films
Authors: Matsuda Asher T , Liaw H. Ming , Cronin Wayne A , Tompkins Harland G , Fejes Peter L , Evans Keenan L 
Published: April 2011

ABSTRACTReactively-sputtered, polycrystalline thin film aluminum nitride (AlN) is an attractive material for use in acoustic wave devices, for which it requires a strong preferred orientation, similar to that found in epitaxial films. This investigation evaluated the grain structure including preferred orientation, grain size, and surface morphology of sputtered A1N films. The characterization techniques utilized included x-ray diffraction (XRD), secondary ion mass spectroscopy (SIMS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). The results revealed two types of grain structure: 1) a single-grain columnar structure that is perfectly oriented in the [001] direction throughout the entire film thickness and 2) a multiple-grain columnar structure that possesses a strong [001] orientation at the bottom of the film and a tilted [001] combined with other orientations at the top of the film. Strong correlations between orientation and surface morphology, oxygen content, and grain size were observed, namely higher degrees of c-axis orientation correlated with lower mean surface roughness values, reduced oxygen concentration, and narrower grains.
On the Relationship between Calculations and Measurements of the Free Volume of Grain Boundaries
Authors: Mehta S. C. , Smith D. A. 
Published: April 2011

ABSTRACTGrain boundary free volume, simply defined as the difference between the volume of a bicrystal and that of a single crystal containing an equal number of atoms, provides a good measure of average grain boundary coordination. Free volume is useful because (a) computer calculations suggest that the grain boundary free volume scales with the grain boundary energy and (b) experimental measurement of free volume may be relatively easier and more direct than that of grain boundary energy. The objective of this paper is to compare the predictions from computer models of grain boundary free volume with experimental measurements.
Characteristics of Sub-micron Polysilicon Thin Film Transistors
Authors: Olasupo Kola R , Hatalis Professor M. K. 
Published: April 2011

AbstractThe polysilicon thin film transistor has been actively studied for the large area display applications like active matrix liquid crystal displays and for load cell in static random access memories. Due to low effective carrier mobility in polysilicon, the circuit speed is limited. Since the circuit delay time is directly proportional to the square of the channel length, short channel TFTs will be advantageous for high speed applications. In this work, we have studied the current voltage characteristics of an inverted sub-micron P-channel polysilicon thin-film transistor with self-aligned LDD structure to obtain a well-controlled channel and drain offset lengths. The particular features we examined are the leakage current and mobility. The leakage current and the ON current were found to be in the picoamp and micro-amp range respectively for devices having channel length in the range of 1.0μm to 0.35μm. Even very small devices having L&W = 0.35μm × 0.35μm exhibited characteristics similar to wider devices. The on/off current ratio was in the order of 105 before hydrogenation.
Flat Panel Display Substrates
Authors: Moffatt Dawne M. 
Published: April 2011

AbstractThe performance of advanced flat panel displays is intrinsically linked to critical properties of the substrate material. In the manufacture of active-matrix liquid crystal displays (AMLCDs) and some emissive displays, there are certain process steps that require extreme conditions such as strong chemical washes and temperatures in excess of 600°C. As a result, the glass substrate used in these displays must be able to withstand these environments without degradation of its properties. It has become apparent that the flat panel display (FPD) manufacturers will benefit from substrates with improved acid durability, higher temperature capability, and thermal expansion coefficients consistent with other display materials.This paper focuses on one of the less-understood features of the glass substrate: the expansion characteristics as a function of temperature. Thermal expansion is important as it affects the compatibility of the glass with display materials, which, in the case of AMLCDs and some silicon-microtip field emission displays (FED), require an expansion close to that of silicon. In addition, thermal breakage during processing is directly proportional to the expansion coefficient.This study focused on the thermal expansion characteristics of two different FPD substrate glasses. The first one is code 7059, manufactured by Corning Incorporated and currently the standard in AMLCDs. A new substrate composition, Corning code 1737, with enhanced durability, temperature capability, and expansion tuned to the AMLCD applications will also be discussed.
Characterization Of Inorganic Contamination In Liquid Crystal Display Materials Using Total Reflection X-Ray Fluorescence (TXRF)
Authors: Hockett R. S. , Metz J. M. 
Published: April 2011

AbstractThis work is a feasibility study for using Total reflection X-Ray Fluorescence (TXRF) to characterize inorganic contamination at the surface of, and in, liquid crystal display materials as a function of their processing. Five samples were taken from process steps called: Cr black mask, Cr pattern, RGB pattern, topcoat, and ITO, all on glass substrates. TXRF, a glancing angle XRF technique, is sensitive to inorganic elements and can be used to detect inorganic contamination at surfaces. In addition, increasing the glancing angle can lead to penetration of thin films, and thereby to some qualitative depth information for the detected elements. Elements detected in this study included: Al, Si, S, Cl, In/Sn, Ca, Ba, Cr, Fe, Cu, Ni and Zn.
Effects of N2 Plasma Treatment on SiO2 Gate Insulator in a-Si:H Thin Film Transistor
Authors: Kim Sung Chul , Bae Sung Sig , Oh Eui Yeol , Kim Jeong Hyun , Lee Jong Wan , Kim Cha Yeon , Kim Donggil 
Published: April 2011

AbstractWe fabricated the high performance a-Si:H TFT using the N2 plasma treated APCVD SiO2 as a gate insulator. The effects of N2 plasma treatment on the APCVD SiO2 were investigated by XPS and SIMS measurements. And the formation of the oxynitride interface layer between a-Si:H and APCVD SiO2 was found in the a-Si:H TFT. From our experimental results, It may be concluded that most nitrogen atoms, which were incorporated by the exposure of SiO2 layer to N2 plasma, exist, not bonded to other atoms, near the surface of the SiO2 layer and during the sequential deposition of a-Si:H on the N2 plasma treated APCVD SiO2 layer Si-N bonds are formed, resulting in the oxynitride layer in the interface region. This explains the high performance a-Si:H TFT with the N2 plasma treated APCVD SiO2 gate insulator.
a-Si TFT Technologies for AM-LCDS
Authors: Ibaraki Nobuki 
Published: April 2011

AbstractA technical trend for a-Si TFTs is their application to large-size, high-pixel density AMLCDs such as XGA, EWS, and HDTV. In order to realize these LCDs, the TFT device characteristics must be improved. Future technologies, which will be necessary to fabricate TFTs with improved characteristics are as follows,(1) Fully self-aligned TFT technology: A SA-TFT structure reduces the feedthrough voltage caused by parasitic capacitance due to gate/source overlap. This results in an improved picture quality and a higher aperture ratio. Fabrication of such a structure would require ion doping technology.(2) Ion doping technology: This non-mass-separated implantation technique has large area doping capability and much higher doping speed compared to conventional ion implantation technique. The major problems with the ion doping technique is the implantation of unwanted species which deteriorate the quality of source/drain and channel regions of TFTs.
Solid-State Luminescent Color Displays
Authors: Pope Edward J. A. 
Published: April 2011

AbstractBy the end of 1994, flat-panel displays for lap-top computers and televisions will exceed $4.0 billion in total sales. Currently, most such displays are based entirely upon an advanced liquid crystal technology requiring several precisely aligned LC layers. A new technology for flat-panel displays, based upon the solid-state luminescence of sol-gel derived microspheres has been proposed. Silica gel-derived microspheres can be prepared at near ambient temperatures, doped with either optically-active organic dye molecules or lanthanide ions. Microspheres doped to give red, blue, and green luminescence can be arranged in a pixel pattern to form the basis of a display screen. A single monochrome LC layer is used to modulate the excitation light, or pump source, that activates the fluorescence of each pixel.
Vector E-Field Probe for Testing Industrial Applicators.
Authors: Roussy Georges , Thiebaut Jean-Marie , Agbossou Kodjo , Dichtel Bernard 
Published: April 2011

ABSTRACTUsing the modulated scatterer technique allows us to measure the electromagnetic field in an applicator. The design of a new sensor modulated at 25 Hz is described. The operating conditions and the performance are presented.The sensor can be used for measuring high microwave electric fields up to 10 kV/m in an industrial applicator supplied by any industrial magnetron.
Dielectric Metrology VIA Microwave Tomography: Present and Future
Authors: Bolomey J.Ch. , Joachimowicz N. 
Published: April 2011

ABSTRACTUntil now, the measurement techniques used for the dielectric characterization of materials require severe limitations in terms of sample shape, size and homogeneity. This paper considers the dielectric permittivity measurement as a non-linear inverse scattering problem. Such an approach allows to identify the quantities to be measured and suggests possible experimental arrangements. The problem is shown to be significantly simplified if the shape of the material is known and if some a priori knowledge of the averaged value of the permittivity in the material under test is available. Two test cases have been selected to illustrate the state of the art in solving such inverse problems. The first one consists of a two-dimensional configuration which is applicable to cylindrical objects, and the second one to a vector three-dimensional configuration applicable, for instance, to cubic samples. The main limitations of such an inverse scattering approach are discussed and expected improvements in the near future are analysed.
Novel Routes to Microwave Processing of Ceramic Materials
Authors: Willert-Porada M. 
Published: April 2011

ABSTRACTMaterial parameters important for microwave processing are identified in case of powder synthesis from precursor compounds and in case of sintering Al2O3- as well as SiC-matrix ceramics. By varying the spatial distribution of the precursor in microwave transparent materials, different pyrolysis temperatures are obtained, which can be attributed to different heating rates due to selective microwave heating. The microwave sintering behavior of oxide ceramics is strongly influenced by the specific surface area of the powder and by aliovalent dopants. In contrast, for covalent ceramics, like SiC+TiC, no experimental evidence for similar effects was obtained.
Microwave Absorption in NaCl Crystals with Various Controlled Defect Conditions
Authors: Meng Binshen , Booske John , Cooper Reid , Freeman Sam 
Published: April 2011

ABSTRACTA thorough understanding of fundamental microwave absorption mechanisms in ionic crystalline solids is important for microwave sintering of ceramics, as well as the design of high speed electronic packaging, advanced radomes, etc. Of particular importance to these applications are how the density and type of crystalline defects affect the dominant microwave absorption mechanisms. We have designed experiments to measure microwave absorption in NaCl samples with controlled variations in defect conditions(pure, point defects, dislocations and grain boundaries) at different temperatures (20–400 °C) and frequencies (2–20 GHz). Initial results are reported and discussed.