bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication and Characterization of Color Phosphors Prepared Electrophoretically for 4-inch Full Color Fed Application
Authors: Hong J. P. , Jang J. E. , Jin Y. H. , Kim J. W. , Choi J. H. , You Y. C. , Park N. S. , Kim J. M.
Published: April 2011

Color phosphors have been deposited on indium-tin glasses by utilizing an electrophoretic process for the application to prototype 4-inch full color FED devices. The deposition suspension is prepared with color phosphors of l-3um size, isopropanol, charger and binder. Various parameters, such as deposition time and applied voltages, are systematically performed to this end. As a result, each phosphor exhibited uniform thickness of about 6–10um over the whole plate. Electrical properties of the deposited phosphors are investigated and compared both in the vacuum chamber and in fully-sealed 4” FED conditions. In addition, they are extensively characterized by the SEM and 3-dimentional analysis. Experimental results confirm that the phosphor quality in real FED devices is significantly affected by deposition conditions.
The Dependence of Phase Separation of PDLC on the sample preparation Conditions of TFT LCD Panel
Authors: Noh C. H. , Park K. S. , Sakong D. S.
Published: April 2011

The electro-optical property of PDLC had been improved by optimizing synthetic conditions such as control of crosslinking density of polymer and formulation. The PDLC materials had low driving voltage, high contrast ratio and high reliabilities for the long-term operation. But there remained some problems for applying to TFT LCD panel. The panel structure of TFT LCD was different from that of the transparent ITO glass because TFT LCD panel had many opaque parts such as transistor elements, metal electrodes and black matrix. Opaque parts of TFT panel shielded UV light and resulted in quite - different phase separation behaviors of PDLC prepared from the transparent ITO glass cell.

The sample preparation conditions in TFT panel had to be changed to obtain similiar electro-optical property with ITO glass cell. Changes of UV intensity and photoinitiator species of the PDLC TFT panel were effective to obtain good results. Contrast of the panel and physical property of the liquid crystal could be improved to the level of ITO glass panel.
Substrate Issues for Advanced Display Technologies
Authors: Moffatt-Fairbanks Dawne M. , Tennent David L.
Published: April 2011

The glass substrate plays a crucial role in the successful performance of advanced flat panel displays (FPDs). These FPD technologies include active-matrix liquid crystal displays (AMLCD) and Plasma Displays (PDP). Although these displays are different in the way in which they operate, there are several common substrate requirements, all of which are determined by the process for making the entire display. These include issues relating to substrate size, thermal shrinkage, high temperature stability, and substrate surface quality.

While AMLCD technology is moving toward larger sizes, PDPs are currently large size displays, requiring large glass substrates. The primary issue in using larger substrates is minimizing distortion of the glass during high temperature processes, both viscous sag and shrinkage. These are related to the high temperature thermal stability which, in turn, is largely determined by the strain point and thermal history of the substrate. Finally, thickness uniformity and surface flaws are critical to the performance of the final display.

Coming's Code 1737 glass substrate meets the requirements for AMLCDs and has become the industry standard. Corning/Saint-Gobain Code CS25 glass is a new glass that has significant benefits over soda-lime glass for PDP applications. This paper will discuss these two glasses in terms of the above-mentioned issues.
Noise and Operational Characteristics of Magnetometers Made from Superconducting-Normal-Superconducting Josephson Junctions
Authors: Reagor D. , Mombourquette C. , Decker J. , Fan Y. , Hawley M. , Houlton R. , Jia Q. X.
Published: April 2011

We have fabricated numerous magnetometers using our high temperature superconducting (HTS) Josephson junctions. These Josephson junctions are fabricated in a superconducting-normal-superconducting ramp edge configuration1 with silver doped YBa2Cu3O7 (YBCO) for the superconducting electrodes and PrBa2Cu3O7, (PBCO) for the normal layer. Small inductance quantum interference devices (SQUEDs) made from this junction technology have a transfer function exceeding 150 microvolts per flux quanta and a flux noise of 5×10−6flux quanta per root hertz. In addition, we have established that these junctions have identical electrical characteristics after either a year of storage or repeated thermal cycling. We have also examined the trade-off of 1/f noise versus thermal noise that is obtained as we vary the critical current of the devices.

The SQUID magnetometers were made using galvanically coupled input coils. These devices exhibit excellent operational characteristics in the geomagnetic field. They functioned in an unshielded environment for more than 24 hours and operated in a moving dewar (without any feedback fields to compensate the changing applied field) - both without flux trapping. Noise characteristics under these conditions are presented.
Structural Inhomogeneities and Resistivity in Radiation Damaged LA2/3(CA,SR)1/3MNO3-δ Pulsed Laser Deposited Thin Films
Authors: Stroud R. M. , Browning V. M. , Byers J. M. , Chrisey D. B. , Fuller-Mora W. W. , Grabowski K. S. , Horwitz J. S. , Kim J. , Knies D. L. , Osofsky M. S.
Published: April 2011

The relationship between structural distortions and resistivity in pulsed laser deposited La2/3Ca1/3MnO3 (LCMO) and La2/3Ca1/3MnO3 (LSMO) thin films was investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM) and resistivity measurements. The growth defects inherent to annealed films were characterized, and then additional defects were introduced by radiation damage. Epitaxially grown films on (100) LaA1O3 substrates exhibited three primary types of growth defects: interface strain, column boundary mismatch, and column rotation. High resolution TEM measurements show well-ordered regions of film that offer low resistance paths for current flow around growth defects. A series of annealed samples were irradiated with 6 Mev Si+3 ions to produce 0.006 to 0.024 displacements per atom (dpa) in LCMO films, and 0.028 to 0.14 dpa in LSMO films. The peak resistance temperature (Tp) was found to depend strongly on defect concentration, varying from 235K ± 15K for the unirradiated LCMO films to 95K for 0.018 dpa. At 0.024 dpa, the LCMO film was insulating at all temperatures. LSMO films showed a downward shift in Tp from 300K for an unirradiated film to 250K for 0.028 dpa, and complete insulating behavior for 0.14 dpa.
The Effects of Strain on The Magnetic Anisotropy of Doped Manganite Thin Films
Authors: Suzuki Y. , Tsai C. , Hwang H. Y. , Cheong S-W. , Van Dover R. B.
Published: April 2011

We show the importance of the role of strain in doped manganite perovskite materials by revealing the dominance of stress anisotropy effects over magnetocrystalline anisotropy effects in the magnetic anisotropy of these films. In order to measure magnetic anisotropy in the plane of the films, remnant magnetization was measured as a function of in-plane angle. The (110) La0.7Sr0.3MnO3 films reveal a twofold symmetry while the (100) films have fourfold symmetry. Temperature dependence of the magnetic anisotropy of La0.7Sr0.3MnO3 films reveals decreasing anisotropy as the Curie temperature is approached.
Mocvd of Polycrystalline and Epitaxial Complex Oxides by Liquid Delivery
Authors: Roeder J. F. , Bilodeau S. M. , Carl R. J. , Baum T. H. , Van Buskirk P. C. , Woolcott R. R. , Kingon A. I.
Published: April 2011

A unique approach to MOCVD of complex oxides enables deposition of a number of materials of technological importance through the use of liquid delivery of metalorganic precursors. Methodologies for control of composition and exploration of. process space are compared for two film systems, one in a relatively mature state of development ((Ba,Sr)Ti03), the other in an early state of development (Ni-ferrite). In both cases, composition was controlled by mixing metalorganic precursors dissolved in solvents using a liquid delivery system. Films with excellent crystalline quality were deposited in both cases. Polycrystalline BST films displayed properties suitable for DRAM applications: charge storage densities > 80 fF/μm2 and leakage current density < 10−8 A/cm2 for films as thin as 15 nm. Growth mechanisms and rates were determined for the single component oxides of the ferrite films. Epitaxial NiFe204 films were deposited on MgO single crystal substrates at 650°C; x-ray rocking curves yielded FWHM values of 0.046°, commensurate with the substrate.
Magnetic and Crystalline Microstructure of SrRuO3 Thin Films
Authors: Marshall A. F. , Klein L. , Ahn C. H. , Dodge S. , Reiner J. , Antognazza L. , Mieville L. , Kapitulnik A. , Geballe T. H. , Beasley M. R.
Published: April 2011

The relationship between the magnetic and crystalline microstructure of SrRu03 thin films is analyzed using transmission electron microscopy. Regions with a stripe magnetic domain structure in different orientations are observed in Lorentz imaging mode when the specimens are zero-field-cooled through the ferromagnetic transition temperature, Tc ≈ 150K. The different orientations of the stripe regions correspond to different crystallographic domains as determined by electron diffraction and magnetic image contrast; all of the six possible orientations of the orthorhombic SrRuO3 structure grown epitaxially on a SrTiO3 cubic substrate are identified. The results show that the uniaxial anisotropy indicated for these multi(crystal)domain films is the same as that determined for single crystal films by bulk magnetization measurements, and is therefore primarily magnetocrystalline in nature.
The Effect of Miscut Angle and Miscut Direction of Vicinal (001) SrTiO3 Substrates on The Domain Structure of Epitaxial SrRuO3 Thin Films
Authors: Gan Q. , Rao R. A. , Eom C.B
Published: April 2011

We have grown epitaxial thin films of isotropie metallic oxide SrRuC>3 on both exact and vicinal (001) SrTiO3 substrates with miscut angle (α) up to 5.0° and miscut direction (β) up to 37° away from the in-plane [010] axis. The effects of both α and β on the epitaxial growth and domain structure of epitaxial SrRuC>3 thin films were studied by x-ray diffraction and atomic force microscopy (AFM). On vicinal SrTiO3 substrates with a large miscut angle (α = 1.7°, 2.0°, 4.1°, and 5.0°) and miscut direction close to the [010] axis, single crystal epitaxial (110)° SrRuO3 thin films were obtained. [The superscript o refers to the Miller indices based on the orthorhombic unit cell.] Decreasing the substrate miscut angle or aligning the miscut direction close to the [110] axis (β = 45°) resulted in an increase of 90° domains in the plane. The films grown on vicinal substrates displayed a significant improvement in crystalline quality and in-plane epitaxial alignment as compared to the films grown on exact (001) SrTiO3 substrates. AFM revealed that as the miscut angle increased the growth mechanism changed from two dimensional nucleation to step flow growth.
Fe3O4/MgO Superlattices Grown on MgO(OOl) and Fe/MgO(001) by Molecular Beam Epitaxy
Authors: Chern G. , Chang C. L. , Chean Y. R.
Published: April 2011

The growth and structural characterization of Fe3O4/MgO superlattices on MgO(001) and Fe-coated MgO(001) are compared. Long modulated coherence and sharp interface are revealed by X-ray diffraction and reflection high energy electron diffraction (RHEED). For the superlattice grown directly on MgO(001), high crystalline quality is comparable to the previous report on the oxide superlattice system. For the superlattice grown on Fe/MgO(001), both chemical and lattice spacing modulations are maintained which is different from the polycrystlline structure of the Fe3O4/NiO grown on Ni-based system. This superiority of the growth on Fe-coated surface results from both the smaller lattice mismatch and the oxidation state of Fe relative to MgO. The changes of the RHEED intensity during the growth of these superlattices are also measured. The evolution of the oxide interface during the growth of Fe3O4/MgO is quantitatively presented.
Adsorption-Controlled Growth of Ferroelectric PbTiO, and Bi4Ti3O12 Films for Nonvolatile Memory Applications by MBE
Authors: Theis C. D. , Yeh J. , Hawley M. E. , Brown G. W. , Schlom D. G.
Published: April 2011

Epitaxial PbTiO3 and Bi4Ti3O12 thin films have been grown on (100) SrTiO3 and (100) LaAlO3 substrates by reactive molecular beam epitaxy (MBE). Titanium is supplied to the film in the form of shuttered bursts each containing a one monolayer dose of titanium atoms for the growth of PbTi03 and three monolayers for the growth of Bi4Ti3O12. Lead, bismuth, and ozone are continuously supplied to the surface of the depositing film. Growth of phase pure, c-axis oriented epitaxial films with bulk lattice constants is achieved using an overpressure of these volatile species. With the proper choice of substrate temperature (600 – 650 °C) and ozone background pressure (PO3 = 2×10−5 Torr), the excess of the volatile metals and ozone desorb from the surface of the depositing film leaving a phase-pure stoichiometric crystal. The smooth PbTiO3 surface morphology revealed by atomic force microscopy (AFM) suggests that the PbTiO3 films grow in a layer-by-layer fashion. In contrast the Bi4Ti3O12 films contain islands which evolve either continuously or around screw dislocations via a spiral-type growth mechanism.
Effect of Electron Incidence in Epitaxial Growth of CeO2(110) Layers on Si(100) Substrates
Authors: Inoue Tomoyasu , Yamamoto Yasuhiro , Satoh Masataka
Published: April 2011

With the aim of lowering epitaxial growth temperature, the effect of electron incidence is studied in the epitaxial growth of CeO2(110) layers on Si(100) substrates by electron-beam evaporation in an ultrahigh vacuum. Two growth methods are employed: evaporation under substrate bias application and electron-beam assisted evaporation. In evaporation at positive substrate bias, electrons and anions from an evaporation source are attracted to the substrate surface, resulting in successful epitaxial temperature lowering. It is clarified that facilitation of the epitaxial growth is attributed only to electron incidence. The electronic current component is measured to be on the order of 10−4 A, about half of the total current. In using electron-beam assisted evaporation for higher current (10−3 A), electron-beam irradiation is demonstrated to have a much greater effect in both the growth temperature lowering and the crystalline quality improvement. The epitaxial growth facilitation effect increases with electron energy in both evaporation methods. It is clarified that the epitaxial growth temperature is lowered to 720°C, i. e., epitaxial growth temperature lowering of ∼100°C compared with the conventional growth method, both by evaporation with substrate bias at +240 V and 240 eV-electron-beam assisted evaporation, wherein the latter produces higher crystalline quality layers.
Imaging of Multilayers with Fresnel Contrast by Transmission Electron Microscopy
Authors: Galtier P. , Valet T.
Published: April 2011

Diffraction contrast and high resolution imaging, which are generally used to visualize multilayers, fail when they are applied to study metallic multilayers (MLs) composed of elements with close atomic number. In such a case (i.e. Co/Cu multilayers) neither the absorption nor the structure can give enough contrast between elements to observe the details of the multilayer stacking. This is illustrated in Figure 1.a which shows a bright field image of (NiFe/Cu/Co/Cu)x8 multilayers deposited on Si. Thus, although the existence of a multilayer structure is clearly demonstrated by both small angle X-ray diffraction and electron diffraction ‘, this does not appear clearly in the images in diffraction contrast. In such systems, if the crystals in the layers are not in strong diffracting condition, absorption is the predominant cause of contrast, and since the constituent elements have extremely close Z, the absorption will be identical for all the layers leading to little or not contrast. However, the contrast can be enhanced by defocusing the objective lens of the microscope leading to the appearance of Fresnel fringes at the interface between the layers (Figure l.b). In this study we investigate the field of application of this contrast mode to extract both qualitative and quantitative information in metallic multilayers. We show that the fine details of the Fresnel fringes can be described quantitatively in order to assess the thickness and waviness of the layers, and the interface sharpness.
Effects of Arriving Atom Kinetic Energy on the Structure and Magnetic Properties of Thin Sputter-Deposited Films
Authors: Wilson R. J. , Minvielle T. J. , Hildner M. L. , White R. L.
Published: April 2011

Thin multilayer films are of growing importance as magnetic sensors. One key parameter in their performance is the interlayer magnetic coupling field which can vary in both sign and strength. Experiments performed to explore the effects of sputter deposition methods on the coupling fields observed for Co/Cu multilayers and spin valves on single crystal substrates are described. Scanning Tunneling Microscopy is used to qualitatively understand the large differences in observed coupling fields.
Magnetic Properties and Structure of Metallic Multilayers Investigated by NMR
Authors: Panissod P. , Mèny C. , Wójcik M. , Jedryka E.
Published: April 2011

As a probe of the short range chemical and topological order, NMR is useful for structural investigations of magnetic multilayers (interface structure and composition, bulk phases and defects, strains). The magnetic character of the raw data makes it also possible to study local magnetic properties of these composite systems, and to correlate them with local structural features. The hyperfine field is the first output of an NMR experiment which gives a direct insight on the local magnetization in ferromagnets. NMR is also sensitive to the restoring torque exerted on the electronic moment by the local magnetic anisotropy and/or exchange and dipolar couplings. Combined with the fact that the various parts of a sample (atomic planes involved in the interfaces, bulk phases and bulk defects) can be discriminated in the spectra, the magnetic information contained in the data allows to probe quantitatively or, at least, to place on a relative scale, the different magnetic responses of the different parts of a sample. We present here the relevant results which we have obtained in the course of our investigations of Co based multilayers and spin valves (interface magnetic profiles, inhomogeneities of magnetic anisotropy and of magnetic coupling).
Fabrication of Micron Scale Magnetic Nickel Features by Selective Area Organometallic Chemical Vapor Deposition
Authors: Welipitiya D. , Borca C. N. , Dowben P. A. , Gobulukoglu I. , Jiang Hong , Robertson B. W. , Zhang Jiandi
Published: April 2011

We demonstrate that it is possible to deposit a wide range of magnetic features, using photoassisted and electron radiation induced selective area organometallic chemical vapor deposition. Large arrays of identical micron to nano scale Ni features were deposited by these methods. Their magnetic properties were studied by alternating gradient force magnetometry as well as magnetic force microscopy. Our morphological and magnetic measurements show that the structures are spatially well defined, and the magnetic properties are related to the structural shapes of the features.
Magnetic Anisotropy and Rotational Hysteresis Loss in Epitaxial TbFe2(110) Films
Authors: Wang Chuei-Tang , Khanna Gaurav , Clemens Bruce M. , White Robert L.
Published: April 2011

The effect of in-plane strain on the magnetic anisotropy of [110]-oriented epitaxial TbFe2 films was studied. DC magnetron cosputtering was used to grow epitaxial TbFe2(110) films on A12O3(1120) substrates with an epitaxial Nb(110) buffer layer. Torque magnetometry showed that the films had uniaxial anisotropy, and the torque curves were used to determine the magnetic anisotropy constants of the films by analyzing the rotational hysteresis loss. Film strain was measured using synchrotron radiation. The film strain and anisotropy measurements confirm that the uniaxial anisotropy results from tensile strain in the TbFe2(110) films. This agrees with theoretical calculations of magnetic anisotropy which show that tensile strains can induce a uniaxial anisotropy in TbFe2(110) films.
Magnetic Domain Imaging with a Photoemission Microscope
Authors: Schneider C.M. , Frömter R. , Ziethen C. , Swiech W. , Brookes N.B. , Schönhense G. , Kirschner J.
Published: April 2011

Photoelectron emission microscopy (PEEM) has proven to be a versatile analytical technique in surface science. When operated with circularly polarized light in the soft x-ray regime, however, photoemission microscopy offers a unique combination of magnetic and chemical information. Exploiting the high brilliance and circular polarization available at a helical undulator beamline, the lateral resolution in the imaging of magnetic domain structures may be pushed well into the sub-micrometer range. Using a newly designed photoemission microscope we show that under these circumstances not only domains, but also domain walls can be selectively investigated. The high sensitivity of the technique yields a sizable magnetic contrast even from magnetic films as thin as a fraction of a single monolayer. The combination of chemical selectivity and information depth is successfully employed to investigate the magnetic behavior of buried layers and covered surfaces. This approach offers a convenient access to magnetic coupling phenomena in magnetic sandwiches.
Angle- and Temperature- Dependent Magnetic Circular Dichroism in Gd(0001) Core-Level Photoemission
Authors: Morais J. , Denecke R. , Ynzunza R. X. , Menchero J.G. , Liesegang J. , Fadley C. S.
Published: April 2011

Recent results on the dependence of the magnetic circular dichroism on the angle and temperature for thick (100 ML) films of Gd(0001) are presented. Strong dichroic effects were observed in 4d core-level photoemission for the magnetized films, which showed excellent agreement with an atomic many-particle description recently published [1]. The angular dependence of the magnetic dichroism has been discussed taking into account photoelectron diffraction effects. In addition, an indication of a higher surface Curie temperature has been observed in the temperature- dependent measurements.
Spin Reorientation in Fe/Cu(100) and Cu/Fe/Cu(100)
Authors: Mentz E. , Bauer A. , Weiss D. , Kaindl G.
Published: April 2011

In-situ scanning tunneling microscopy (STM). magneto-optical Kerr effect (MOKE) and Kerr microscopy are used to investigate the relations between structure, morphology, and magnetism in low-temperature (LT) grown Fe/Cu(100) films. At the spin reorientation thickness of ≈ 3.8 monolayers (ML) Fe/Cu(100) the coexistence of in-plane and out-of-plane magnetized domains is observed. For Fe thicknesses between 3.8 and 6 ML Fe/Cu(100). an irreversible spin reorientation from in-plane to out-of-plane can be induced by annealing up to 420 K. Annealing of LT-grown Fe/Cu(100) films is proposed to provide smooth surfaces for Cu/Fe/Cu(100) sandwich preparations.
Fe-Cr-N Based Nanocrystalline Soft Magnetic Thin Films
Authors: Zhu W. , Tiefel T. H. , Jin S. , Van Dover R. B. , Korenivski V.
Published: April 2011

We have investigated the soft magnetic properties of new Fe-Cr-Ta-N and Fe-Cr-Hf-N alloy films. Thin films with compositions in the range of Fe-2∼8%Cr-0∼l%Ta (or Hf)-5∼10%N (in atomic %) were prepared by reactive sputtering in a nitrogen-containing atmosphere. The films, most likely nanocrystalline, exhibit excellent soft magnetic properties in the as-deposited condition without any post-deposition heat treatment, e.g., Hc∼l-2 Oe and 4πMs∼15–20 kG. The magnetic properties are highly anisotropie in the film plane as the easy-axis M-H loop is square and the hard-axis loop is linear and closed, with the anisotropy field Ha=20–100 Oe. The films exhibit excellent high frequency behavior even in the GHz frequency range which is attributed to the combination of high 4πMs and relatively high Ha.
Structural and Magnetoresistance Studies of Ni/Co Multilayers
Authors: Freitag J.M. , Ström-Olsen J.M. , Altounian Z. , Cochrane R.W.
Published: April 2011

A study of ferromagnetic/ferromagnetic Ni/Co multilayers grown by DC magnetron sputtering with component layer thicknesses between 40 and 5 Å is presented. Structural characterization by small-angle x-ray reflectivity reveals high-quality layered structures with a well-defined composition modulation along the film growth direction. Quantitative interpretation of the superlattice structure parameters, including interface roughness and intermixing, has been performed by modelling the x-ray reflectivity data. Measurements of the magnetotransport properties of these multilayers indicate that the magnetoresistance (MR) effect, Ap ∼ 0.35 μΩ-cm, is roughly constant over the entire compositional range. We attribute the origin of this effect to anisotropie magnetoresistance (AMR). The MR ratio Ap/p, which is as high as 3.0% in a SiO2/(Ni40Å/Co5Å)×6 multilayer with saturation field ∼ 80 Oe, is therefore more strongly dependent on the zero-field resistivity. By fitting a semi-classical model of conduction in multilayers to the resistivity thickness variation, we extracted the mean free paths for conduction in each of the constituent layers as well as the contribution of interfacial scattering in the superlattice structure.
Effects of Symmetry on Circular and Linear Magnetic Dichroism in Angle-Resolved Photoemission Spectra of Gd/Y(0001) and Fe-Ni/Cu(001)
Authors: Goodman K.W. , Tobin J.G. , Schumann F.O. , Willis R.F. , Gammon J.W. , pappas D.P. , Kortright J. , Denlinger J.D. , Rotenberg E. , Warwick A. , Smith N.
Published: April 2011

We have observed circular and linear magnetic dichroisms in angle-resolved photoemission spectra of 50-monolayer Gd films grown on Y(0001) and 6-monolayer Fe-Ni alloy films grown on Cu(001). The 4/level of Gd and the Fe 3p level of the Fe-Ni alloy were measured. A different geometry was used for the magnetic circular dichroism than was used to measure the magnetic linear dichroism. The geometries were chosen so that the magnetic circular dichroism is predicted to be closely related to the magnetic linear dichroism for four-fold symmetric Fe-Ni/Cu(001) but not for three-fold symmetric Gd-Y(0001). Experimental results are presented.
Magnetic Microscopy of Fe/Mn/Fe Layers
Authors: Hopster H. , Iwasaki Y. , Barthel J. , Maiken E.B. , Miller B.P. , Kondis J. , Yu Y.
Published: April 2011

Abstract Manganese layers were deposited on polycrystalline Fe-based soft magnetic films. The magnetic domain structure of thin Fe overlayers on top these Mn films was measured by secondary electron microscopy with polarization analysis. The Fe layers show spin polarization only beyond a certain critical thickness of about 20 Å. Beyond this thickness the domain structure of the substrate starts to appear in the Fe overlayer. This delayed onset of ferromagnetic order in the Fe layers is attributed to frustration of ferromagnetic order due to the strong coupling to the antiferromagnetically ordered Mn. With increasing Fe film thickness (between 20–30 Å) the magnetization increases and shows the same domain pattern as the substrate. We find that for all Mn thicknesses studied (up to 170 Å) the Fe overlayer domain structure reproduces the substrate domain structure and the magnetization is always aligned parallel with the substrate magnetization.
Scanning Auger Microscopy Characterization of Magnetic Hard Disc
Authors: Harris D. W. , Neiman D. L. , Huang J.
Published: April 2011

Applications of Zalar rotation and field emission Auger (FE-AES) analysis in various magnetic hard disc problems will be presented. These applications include thin layer structure characterization, low concentration contaminant (0.1–0.5 atomic percent) detection at deeper interfaces (greater than 1000Å), and small particle (-∼1000Å) contaminant identification.
The Processing and Characterization of Hybrid Silica-Based Xerogel Films
Authors: Chow Loren A. , Yu Ted , Dunn Bruce S. , Tu K. N. , Chiang Chien
Published: April 2011

Hybrid organic-inorganic xerogel films were deposited as porous thin films by spinning the precursor sol on silicon substrates. Films of various compositions were prepared using combinations of the following precursors: methyltrimethoxysilane, dimethoxydimethylsilane and tetramethoxysilane (TMOS). The hybrid films exhibited excellent gap-filling capabilities (0.45 micron trenches). Thermal desorption experiments indicate that heating to ∼130 C removes moisture and volatile organic constituents present in the as-cast film. Curing was found to increase the adhesion between the xerogel and the silicon substrate. Moisture was found to be responsible for an increase in the dielectric constant. That is, in ambient, the dielectric constant for a cured film was found to be 4.4; but in a dry atmosphere, it decreased to 2.5. Current-voltage measurements show the cured hybrid film possesses a breakdown field of 3.4 MV/cm.
Low-K Dielectric Material Chemical Mechanical Polishing Process Monitoring using Acoustic Emission
Authors: Tang Jianshe , Unger Carsten , Moon Yongsik , Dornfeld David
Published: April 2011

Low-k dielectric material removal rate, which is significantly affected by process factors such as polishing load, wafer carrier rotation, platen rotation speed and pad age, is one of the critical issues in CMP planarization of a dielectric film when concerning productivity, throughputs and stabilization of the process, especially when trying to achieve a target polishing thickness. Scratching is another critical issue in low-k dielectric filmi CMP planarization due to the lower hardness relative to silicon dioxide. This research relates to a methodology for in-situ monitoring of the low-k dielectric material CMP planarization process, specifically for monitoring material removal rate and scratch occurrence, using acoustic emission (AE) sensing technology.

Systematic investigations of CMP process variables on AE signals were carried out in this research. The sensitivity of AE to polishing load, polishing speed, wafer surface roughness (wafer pattern density) and pad roughness were verified. The results showed that, under steady state, the AE rms signal increases with increasing polishing load, polishing speed, slurry particle size, wafer surface roughness and pad roughness.

Based on the research in tribology and other application fields of loose abrasive machining such as lapping and polishing, scratching was known to be caused by the presence of particles which are much larger than average slurry particles. It has been proven that scratching can be avoided or reduced by timely cleaning the slurry supply system. Therefore, to avoid scratching, one strategy is to develop an in-situ method for detecting larger particles involved in CMP process. In this paper, the high sensitivity of AE signals to the presence of larger particles during CMP was experimentally verified.
The Effect of Deposition Conditions on the Properties of Vapor-Deposited Parylene AF-4 Films
Authors: Plano M. A. , Kumar D. , Cleary T. J.
Published: April 2011

One potential low dielectric constant material for ULSI multilevel interconnect applications is parylene AF-4, an organic polymer more formally known as Poly (α, α, α’, α’ - tetrafluoro-p-xylylene). In this study parylene AF-4 films were vapor-deposited on silicon wafers by pyrolytic decomposition of the cyclic dimer, cyclodi(α, α, α’, α’ - tetrafluoro-p-xylylene) using four different deposition conditions. Two different wafer temperatures and two different vaporizer temperatures were used, while the chamber pressure was kept constant. High vaporizer temperature and low wafer temperature give the highest deposition rates. It was found that the surface roughness of films of similar thickness showed a dependence on the deposition conditions. The films deposited at a low vaporizer temperature exhibit a smooth surface (RMS ∼ 4 nm) while those deposited at high vaporizer temperature have a rougher surface (RMS ∼ 16 nm). However, other properties of the films remained very similar. The FTIR spectra and refractive indices, both TE and TM, were measured for the films deposited using the four different deposition processes and showed no dependence on deposition conditions. These results indicate that the change in surface roughness is not due to a large difference in the chemical bonding among the films deposited using the four processes. Also, both weight loss and thickness loss of the films were measured after thermal cycling the films to 450°C and no significant differences were observed. This result indicates that the observed increase in surface roughness with increased vaporizer temperature cannot be related to a change in dimer incorporation in the films. Further experiments are planned to investigate the role of the initiation stage of the polymerization on film surface morphology.
Low Dielectric Constant Fluorine Doped Teos Films
Authors: Rana Viren V. S. , Bhan Mohan , Gupta Anand , Hong Soonil , Lee Peter
Published: April 2011

The fluorine doped TEOS films obtained using an inorganic gaseous dopant source (SiF4) and an organic liquid dopant source (TEFS) are described. The stability of fluorine in these films is strongly dependent on process conditions. The limit of stability for the most stable films is described. The gap fill capability of these films was found to depend strongly on the type of the fluorine precursor.
Sidewall Quality and Step Coverage of Thin Fluorosilicate Glass Films
Authors: Weise Mark T. , Selbrede Steven C.
Published: April 2011

The quality of TEOS fluorosilicate glass (FSG) films deposited on deep silicon trenches was investigated by etching the films with 100:1 HF. The etch rate of the top and sidewall surfaces was measured by SEM as a function of FSG fluorine content. The FSG wet etch rate was correlated to the refractive index, stress and fluorine content. The sidewalls were found to etch slower than the top surfaces, suggesting a lower fluorine content on the sidewalls. Additionally, the step coverage of TEOS oxide improved significantly as fluorine content was increased.
The Influence of Fluorine Desorption from ECR-CVD SiOF Film
Authors: Usami Tatsuya , Ishikawa Hiraku , Gomi Hideki
Published: April 2011

The influence of fluorine desorption from SiOF films deposited by biased ECR-CVD was studied. It was found that desorbed F atoms from the SiOF film react with Ti suicide film resulting in forming SiF4 gas. The evolution of SiF4 gas caused the peel-off of the films.
A Detailed Procedure for Reliable Preparation of Tem Samples Using Fib Milling
Authors: Su D. H.-I , Shishido H. T. , Tsai F. , Liang L. , Mercado F. C.
Published: April 2011

Although many publications have discussed focused ion beam (FIB) preparation of TEM samples, few have presented a detailed, step-by-step milling procedure. This is a summary of techniques that evolved over the past 3 years in our laboratory. In addition to describing more traditional mechanical pre-thinning techniques, we introduce a method to pre-thin samples down to thicknesses of the order of 20 μm within 1 hour using a wafer dicing saw. We then discuss different ways to handle mechanically difficult samples such as those prone to delaminate. Our approach to FIB milling is designed to minimize the effects of ion-beam spreading which is responsible for most of the failures to prepare good FIBTEM samples. The technique is presented in a step-by-step fashion including a simple yet reliable method to terminate FIB milling. Examples are shown to illustrate applications to different types of problems including - precision cross-sectioning of integrated circuit (IC) devices, cross-sectioning of samples prone to delamination, and cross-sectioning of specific defect sites. Finally, we discuss the effect of artifacts in the quality of TEM samples.
Focused Ion Beam Milling and Micromanipulation Lift-Out for Site Specific Cross-Section Tem Specimen Preparation
Authors: Giannuzzi L. A. , Drown J. L. , Brown S. R. , Irwin R. B. , Stevie F. A.
Published: April 2011

A site specific technique for cross-section transmission electron microscopy specimen preparation of difficult materials is presented. Focused ion beams are used to slice an electron transparent sliver of the specimen from a specific area of interest. Micromanipulation lift-out procedures are then used to transport the electron transparent specimen to a carbon coated copper grid for subsequent TEM analysis. The experimental procedures are described in detail and an example of the lift-out technique is presented.
A New Procedure for Making Tem Specimens of Superconductor Devices
Authors: Huang Y. , Merkle K. L.
Published: April 2011

A new procedure is developed for making TEM specimens of thin film devices. In this procedure the sample is flatly polished to an overall “ion-mill-ready” thickness so that any point in the 2-D sample plane can be thinned to an electron-transparent thickness by subsequent ionmilling. Using this procedure small regions of interest can be easily reached in both cross-section and plan-view samples. This is specially useful in device studies. Applications of this procedure to the study of superconductor devices yield good results. This procedure, using commercially available equipment and relatively cheap materials, is simple and easy to realize.
An Updated Ion Polishing System for Tem Specimen Preparation of Materials
Authors: Alani R. , Mitro R. J. , Swann P. R.
Published: April 2011

The construction and performance of an improved ion milling instrument are described. The updated instrument is based upon an earlier version fixed low angle ion milling system. The updated system employs two improved guns having the ability of independent variable milling angle adjustment, while operating at high voltage in the vacuum system. The milling rate of these ion guns is typically ≈ 90μm/hr/gun pair for copper at 5keV and 10°. Designed to compliment the variable angle ion gun is a new specimen holder which permits low angle double sided milling. The combination of these two features offers numerous single or double sided milling conditions to facilitate the production of higher quality TEM specimens in less time. The range of ion gun angles encompassed is 0° to 10° for single-sided milling and 0° to ± 10° for double-sided milling. The instrument also incorporates an electronic mechanism to generate directional sector milling which benefits primarily the production of cross sectional TEM specimens and heat sensitive materials since the ion guns are turned off for a portion of time during each revolution. Another new feature of the instrument is chemical ion milling which facilitates the preparation of certain compound semiconductors. The ability of this improved ion milling instrument for rapid ion polishing and improved specimen quality is demonstrated by a number of TEM images of metals, ceramics and semiconductors.
Subcritical Bifurcation from Planar to Cellular Interface in Al – 0.5 wt.% Cu Directionally Solidified
Authors: Fornaro O. , Palacio H. , Biloni H.
Published: April 2011

Samples of the Al – 0.5wt.% Cu system were directionally grown under controlled conditions, to study the role played by the instabilities in the process relatives to the microstructure selection for a given values of interface velocity, and thermal gradient. Using an interface quenching technique and metallographic analysis in longitudinal and transversal cuts of the samples, we determine the transition mechanisms between the different stages of the growth, and associate them to the stability of the solidification front. We study the planar to a cellular transition in different conditions, and although the solidification parameters are in good agreement with the perturbations theory, when analyzing the amplitude of the perturbations during the planar to a cellular transition, the same theory is not able to predict certainly the critical wavelength in this case. Also, we found a subcritical behavior during the transition from a planar to a cellular interface for the diluted Al – Cu system, detecting a hysteresis behavior for the amplitude of the perturbations when it is increasing and then decreasing the interface velocity, through the threshold.
Shape Evolution and Splitting of a Single Coherent Particle
Authors: Zhang J. D. , Li D. Y. , Chen L. Q.
Published: April 2011

The morphology and its evolution of a single coherent precipitate was investigated using the Cahn-Hilliard equation and Khachaturyan's continuum elasticity theory for solid solutions. A cubic solid solution with negative elastic anisotropy and isotropic interfacial energy was considered. The lattice mismatch between the precipitate and the matrix was assumed to be purely dilatational and its compositional dependence obeys the Vegard's law. Both two- and three-dimensional systems were studied. The Cahn-Hilliard equation was numerically solved using a semi-implicit Fourier-spectral method. It was demonstrated that, with increasing elastic energy contribution, the equilibrium shape of a coherent particle gradually changes from a circle to a square in two dimensions, and from a sphere to a cube in three dimensions, and the composition profile becomes increasingly inhomogeneous within the precipitate with the minimum at the center of the particle, consistent with previous theoretical studies and experimental observations. It was also shown that, with sufficiently large elastic strain energy contribution, a coherent particle may split to four particles from a square, or eight particles from a sphere, during its evolution to equilibrium. For both two and three dimensions, the splitting starts by nucleating the matrix phase at the center of the particle.
Three-Dimensional Simulations of Phase Separation in Model Binary Alloy Systems with Elasticity
Authors: Orlikowski D. , Sagui C. , Somoza A. S. , Roland C.
Published: April 2011

We report on large-scale three-dimensional simulations of phase separation in model binary alloy systems in the presence of elastic fields. The elastic field has several important effects on the morphology of the system: the ordered domains are subject to shape transformations, and spatial ordering. In contrast to two-dimensional system, no significant slowing down in the growth is observed. There is also no evidence of any “reverse coarsening” of the domains.
Stress-Driven Collective Nucleation of Dislocation Loops
Authors: Sun Y. Q. , Hazzledine P. M. , Dimiduki D. M.
Published: April 2011

This paper presents an analysis of the collective nucleation of glide dislocation loops under the bias of a high shear stress. It introduces the concept of an ‘induced’ stress field associated with the planar distribution of glide dislocation loops. It shows that, due to the ‘induced’ field, glide dislocations nucleate in a collective, self-catalytic fashion at critical stresses and temperatures.
Kinetics of Ordering in Cu3Au
Authors: Lang H. , Pfeiler W.
Published: April 2011

L12-long-range ordering (LRO) was studied by residual resistometry in Cu3Au. Variations of LRO-parameter were produced by isochronal and isothermal heat treatments for different initial states of order. By comparison of order-order and disorder-order relaxations, the contributions to ordering of atomic jumps within ordered domains and of antiphase boundaries were separated. Analysing isothermal annealings yielded ordering energies of vacancies involved.
Nucleation & Growth of Precipitates in Transformations Driven by Diffusion
Authors: Clavaguera N. , Clavaguera-Mora M.T.
Published: April 2011

A theoretical analysis of the transformation kinetics which accounts for nuclei, either prequenched or created homogeneously, and whose growth are controlled by diffusion is presented. The change in growth habit intervening during the transformation is analysed in terms of the evolution of the free energy difference between the precipitate and the matrix at the interface, ΔG1. In the Avrami formalism, this quantity accounts for the competition between interface and diffusion controlled growth whereas the nucleation events are driven by the free energy difference between the precipitate and the bulk matrix. Competition and selection of precipitate phases in highly undercooled melts using the CALPHAD approach for the evaluation of the free energies and the changes in diffusivity with concentration are analysed. Experimental vs. calculated data are discussed in some rapidly solidified metallic systems.
Precipitation Kinetics in an Air-Cooled Aluminum Alloy: A Comparison of Scanning and Isothermal Calorimetry Measurement Methods
Authors: Smith George W.
Published: April 2011

The purpose of this work is to study precipitation kinetics in air-cooled aluminum alloy 339 by both differential scanning calorimetry (DSC) and differential isothermal calorimetry (DIC) and thereby establish the equivalence of the two methods. To accomplish this, precipitation time constants, τ and activation energies, Eact, were determined by both techniques. Kissinger analysis of the DSC data yielded Eact and τ values. Using DIC we measured precipitation time constants, Arrhenius plots of which gave Eact. Activation energies and τ values from both methods agree provided DSC temperature scan rates are slow compared to the instrumental lag time. Thus, DSC and DIC have been shown to be equivalent (at least for this test case).
Underpotential – Overpotential Phase Transformation Phenomena in Copper Deposition Processes on Glassy Carbon
Authors: Arzhanova T. A.
Published: April 2011

The initial stages of copper electrodeposition on glassy carbon were studied from a solution of 1 M CuSO4 in 0.5 M H2SO4 by the methods of potentiostatic current transients and pulse experiments. The experimental data were analyzed according to the theory of potentiostatic current transients for three-dimensional multiple nucleation with diffusion controlled growth. The theory was found to be in good agreement with experimental data for instantaneous copper nucleation in the cathodic overpotential range η = −0.18 – −0.40 V. It is shown that in case of progressive nucleation at η ≤ −0.16 V, this theory can be used only for trend analysis of copper nucleation process parameters. An important influence of the initial state of glassy carbon surface on the nucleation rate was found determined by the underpotential. It is shown that the dependence of nucleation rate on the underpotential is inadequate and is determined by cathodic overpotential.
Characterization of Composite Ceramic High Level Waste Forms
Authors: Frank S. M. , Bateman K. J. , DiSanto T. , Johnson S. G. , Moschetti T. L. , Noy M. H. , O'Holleran T. P.
Published: April 2011

Argonne National Laboratory has developed a composite ceramic waste form for the disposition of high level radioactive waste produced during electrometallurgical conditioning of spent nuclear fuel. The electrorefiner LiCl/KCl eutectic salt, containing fission products and transuranics in the chloride form, is contacted with a zeolite material which removes the fission products from the salt. After salt contact, the zeolite is mixed with a glass binder. The zeolite/glass mixture is then hot isostatic pressed (HIPed) to produce the composite ceramic waste form. The ceramic waste form provides a durable medium that is well suited to incorporate fission products and transuranics in the chloride form. Presented are preliminary results of the process qualification and characterization studies, which include chemical and physical measurements and product durability testing, of the ceramic waste form.