bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Method Of Measuring Hydrogen Diffusivity By Hydrogen Permeation Technique II: Experimental Studies
Authors: Zheng Yong-Ping , Zhang Tong-Yi 
Published: April 2011

ABSTRACTIn order to verify the results predicted by the model in Part I of this work [1], permeation experiments were conducted at room and high temperatures on fully-annealed-commerciallypure iron with two kinds of surface treatment, one group with plasma cleaning and presputtering and the other without it. The experimental results show that the diffusivity evaluated by the new model is independent of sample thickness and surface treatment, while the diffusivity evaluated by the time-lag model varies two orders of magnitude. The experimental results confirm that a fine surface treatment yields a low energy barrier for desorption. The energy barrier for either group is higher than the activation energy of diffusion. Consequently, the ratio of drift velocity through surface to that in bulk increases with increasing temperature and makes the time-lag method appropriate at elevated temperatures.
Determination of Hydrogen in Metals, Semiconductors, and Other Materials by Cold Neutron Prompt Gamma-Ray Activation Analysis
Authors: Paul R. L. , Lindstrom R. M. 
Published: April 2011

ABSTRACTCold neutron prompt gamma-ray activation analysis has proven useful for nondestructive measurement of trace hydrogen. The sample is irradiated in a beam of neutrons; the presence of hydrogen is confirmed by the emission of a 2223 keV gamma-ray. Detection limits for hydrogen are 3 mg/kg in quartz and 8 mg/kg in titanium. We have used the technique to measure hydrogen in titanium alloys, germanium, quartz, fullerenes and their derivatives, and other materials.
Hydrogenation of Undoped and Nitrogen Doped Cdte and ZnSe Grown by Molecular Beam Epitaxy
Authors: Hirsch L. S. , Setzler S. D. , Ptak A. J. , Giles N. C. , Myers T. H. 
Published: April 2011

ABSTRACTHydrogen incorporation in both undoped and nitrogen-doped CdTe and ZnSe is investigated. Evidence for a strong nitrogen-hydrogen interaction is presented. Preliminary data indicate that the growth of CdTe and ZnSe under an atomic hydrogen flux results in a significant concentration of paramagnetic defects possibly accompanied by enhanced auto-doping from residual impurities.
Optical Absorption Study of Hydrogen In Zn-Doped Si
Authors: Suezawa M. 
Published: April 2011

ABSTRACTWe studied the interaction between hydrogen (H) and Zn or Zn-related defects in Zn-doped Si crystals from the measurements of optical absorption spectra of hydrogen bound to Zn or Znrelated defects. We doped Si crystals with Zn by annealing the crystals in Zn vapor at 1200°C followed by quenching. After Zn-doping, we doped specimens with H by annealing them in a hydrogen atmosphere followed by quenching. We measured optical absorption spectra of the above specimens at about 6 K by means of FT-IR spectrometry. Many optical absorption peaks were observed; some are due to electronic transitions and some are due to vibrational transitions of H vibration. Hydrogen atoms are known to passivate Zn acceptors since the optical absorption intensity associated with electronic transitions become much weaker after hydrogenation. Absorption peaks associated with H vibration are known to be related to complexes composed of one Zn atom and two hydrogen atoms. We concluded this from studies on the effect of co-doping with H and deuterium and the effect of Zn isotopes on the optical absorption spectra due to H.
Hydrogen and Hydrogen-Related Defects in CVD Diamond
Authors: Rutledge K. M. McNamara 
Published: April 2011

ABSTRACTHydrogen is a detrimental impurity in many chemical vapor deposited (CVD) materials, particularly those involved in electronic or optical applications. For example, active hydrogen defects have been observed in materials such as silicon, Si, gallium arsenide, GaAs, and diamond, C, thin films. Hydrogen and its related defects can be identified, quantified, and observed using magnetic resonance techniques. These techniques allow a unique quantitative, non-destructive view of hydrogen in the solid-state. Nuclear magnetic resonance (NMR) is used to study hydrogenated defects directly, while electron paramagnetic resonance (EPR) is used to observe hydrogen associated with paramagnetic defects. These observations can enhance our understanding of the effects of hydrogen incorporation on the properties of such materials.
The Influence of Surface Morphology and Oxide Microstructure on the Nucleation and Growth of Uranium Hydride on Alpha Uranium
Authors: Hanrahan R. J. , Hawley M. E. , Brown G. W. 
Published: April 2011

ABSTRACTWhile the bulk kinetics of the uranium-hydrogen reaction are well understood, the mechanisms underlying the initial nucleation of uranium hydride on uranium remain controversial. In this study we have employed environmental cell optical microscopy, Scanning Electron Microscopy (SEM) and Atomic Force Microscopy, (AFM) in an attempt to relate the structure of the surface and the microstructure of the substrate with the susceptibility and site of hydride nucleation. Samples have been investigated with varying grain size, inclusion (carbide) concentration, and thermal history. There is a clear correlation to heat treatment immediately prior to hydrogen exposure. Susceptibility to hydride formation also appears to be related to impurities in the uranium. The oxidized surface is very complex, exhibiting wide variations in thickness and topography between samples, between grains in the same sample, and within individual grains. It is, however, very difficult to relate this fine scale variability to the relatively sparse hydride initiation sites. Therefore, the surface oxide layer itself does not appear to control the sites where hydride attack is initiated, although it must play a role in the induction period prior to hydride initiation.
Monte Carlo Atomistic Simulation of Polycrystalline Aluminum Deposition
Authors: Rubio J. Emiliano , Jaraíz Martín , BaiIón Luis A. , Barbolla Juan , López M José , Gilmer George H. 
Published: April 2011

ABSTRACTA new atomistic scheme for simulating polycrystalline thin film deposition based on a Monte Carlo approach has been developed. Simulations of polycrystalline aluminum deposition and annealing at different temperatures are presented. The time evolution of the film morphology for those temperatures is discussed. During deposition, columnar growth is observed at low temperatures. Grain growth takes place mainly during annealing. Faceting and selection of preferred crystal orientations (texture) is observed.
Morphology of NISI Film on Si(100): Role of the Interface Strain
Authors: Maillard-Schaller Eliane , Boyanov B. I. , English S. , Nemanich R. J. 
Published: April 2011

ABSTRACTThe role of strain on the thermal stability of NiSi has been studied by deposition and annealing of Ni on strained and relaxed Si(100) n-type substrates. Strained Si substrates have been produced by depositing a pseudomorphic silicon film on top of a 3000 Å thick relaxed Si0.8Ge0.2film. Raman spectroscopy has proved the top silicon film to be strained. The presence of the characteristic hatch-cross pattern has been confirmed by Atomic Force Microscopy (AFM). Scanning electron microscopy (SEM) and Photoelectron emission microscopy (PEEM) show that the islanding of the NiSi film appears at lower temperature on the bulk silicon substrate (600°C) than on the strained silicon substrate (700°C). The improved thermal stability of NiSi on strained Si can be explained by the difference in relative interface energy of NiSi on strained and relaxed silicon. The thermal expansion coefficient of Ni being 3 times larger than that of Si, NiSi is in compression on Si at 500°C already. The correlation of this compression state with the lattice parameters of bulk and strained Si (100) produces an increased NiSi islanding probability on bulk Si (100) with respect to strained Si.
Solution Delivery for Copper CVD Using Cu(HFAC)2 Reduction
Authors: Zeng C. , Borgharkar N. S. , Griffin G. L. , Fan H. , Maverick A. W. 
Published: April 2011

ABSTRACTWe have developed a solution delivery technique for performing copper CVD using the reduction of Cu(hfac)2 [where H(hfac) = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionel. We have obtained deposition rates of up to 3.6 mg cm−2 hr−1 (ca. 60 nm min−1) for a deposition temperature of 300 °C and reactor conditions of 40 Torr H2, 12 Torr isopropanol, and 1 Torr Cu(hfac)2. The increased rates are several times faster than growth rates observed using conventional Cu(hfac)2 sublimation with pure H2 as the carrier gas. We compare growth rates and film microstructure using TiN- and WNx-coated substrates. We also give preliminary results showing how the partial pressures of H2, i-PrOH, and Cu(hfac)2 each influence the deposition rate.
Effect of Oxygen on the Degradation of Ti-Si-N Diffusion Barriers in Cu Metallization
Authors: McArthur W. F. , Ring K. M. , Morgan B. , Hurst Q. , Serber D. , Clark A. , Kavanagh K. L. 
Published: April 2011

ABSTRACTAmorphous Ti-Si-N thin films are effective barriers to Cu diffusion in integrated circuits that use Cu interconnects. These films are believed to fail as diffusion barriers due to crystallization and subsequent diffusion of Cu along grain boundaries. We prepare thin films of Ti-Si-N by RF magnatron co-sputtering of Ti and Si in Ar/N2. Ti-Si-N films with Si concentrations of 6 to 22% have resistivities <500μΩ-cm. In previous reports we have shown that Si pn-junction diodes metallized with 20nm Ti40Si15N45/Cu do not fail (increased reverse leakage current) until 600%C. When annealed, these films crystallize to yield TiN and Si3N4. In this work we have studied the effect of oxygen on the degradation of the barrier via TEM, diode I-V measurements, and RBS. Oxygen incorporated into the film deposition process improves the barrier effectiveness as measured by diode I-V reverse leakage current. We find no correlation between the amount of O2in the process gas feed stream and the film composition with O resonance analysis (RBS) or crystallinity (TEM).
TEM Observations on the Evolution of Grain Structure in Pressurized Al-0.5Cu Thin Films
Authors: Yang H.D. , Kim C.-U. , Saran M. , Le H.A. 
Published: April 2011

AbstractThis paper reports the observations of the grain-refining mechanism found in Al-0.5Cu thin films that are subjected to hydrostatic compressive pressure during the annealing process. The films are deposited on Si substrates and subsequently placed under 60 MPa Ar gas pressure at 400°C. Transmission electron microscopy on these films reveals that plastic deformation occurs by dislocation slip and induces a refined grain structure. Polygonization is the primary mechanism for grain refining, resulting in the formation of sub-grain boundaries.
Bulge Test Investigation of The Influence of Moisture on Mechanical Properties of Thin Polymer Layers
Authors: Nakladal A. , Buchhold R. , Köhler R. , Gerlach G. , Stavrev M. , Wenzel C. , Baumann K. , Nowak B. 
Published: April 2011

AbstractThin polymer layers gain importance as interlevel dielectrics in microelectronic devices. One major drawback of this class of material is instability of mechanical properties under changing climatic condition. The paper deals with evaluation of the bulge test as complementary method for investigation of humidity induced alterations of mechanical properties. It describes measurement of intrinsic as well as humidity induced stress in polymer layers. The given results agree very well with those obtained by substrate bending. Furthermore, bulge testing proved the assumption of earlier work, that change of mechanical stress is due to a humidity induced swelling process that can be described phenomenologically by expansion coefficient and a biaxial Young's modulus independent from relative humidity. Results are given and discussed for two types of polyimide.
Failure of micron scale Single Crystal Silicon bars due to torsion developed by MEMS micro instruments
Authors: Saif Taher , MacDonald N. C. 
Published: April 2011

AbstractWe present an experimental study on a single crystal silicon (SCS) bar subjected to pure torsion using MEMS micro instruments. The bar is in the form of a pillar, anchored at one end to the silicon substrate. It is attached to a lever arm at the other end. The pillar has a minimum cross sectional area at its mid height. The cross section coincides with the (100) plane of SCS. Torsion is generated by applying two equal forces on the lever arm on either side of the pillar. Two micro instruments apply the forces. Each consists of an electrostatic actuator and a component that calibrates it. The actuator generates high force (≈ 200 µN at 50 V) and is capable of developing large displacements (≈ 10 μm). Calibration involves determination of the force generated by the actuator at an applied voltage, as well as the linear and higher order spring constants of its springs. Each microinstrument is thus calibrated independently.With the application of forces by the two micro instruments, a torque is generated which twists the pillar. The angle of twist at different applied voltages are recorded using an angular scale. The corresponding torques are determined from the calibration parameters of the actuators. Torque is applied until the pillar fractures. Two such sample pillars, samples 1 and 2, are tested. There cross sectional areas are 1 and 2.25 µm2. We find that both the pillars behave linearly until failure. The stresses prior to fracture are evaluated based on anisotropic theory of elasticity. Samples 1 and 2 fail at shear stresses of 5.6 and 2.6 GPa respectively. The fracture surfaces seem to coincide with the (111) plane of SCS.
Investigation of The Mechanical Properties and Adhesion of P.V.D. Tungsten Films on Si and Silicon Compounds by Bulge and Blister Tests
Authors: Dupeux Michel , Bosseboeuf Alain , Buttard Denis 
Published: April 2011

AbstractP.V.D. tungsten films deposited on silicon wafers (covered or not with a P.E.C.V.D. silicon oxide, nitride or oxynitride sublayer) were submitted to bulge and blister tests. The mechanical equilibrium and geometry of the bulged tungsten membranes is compared to various models. From this analysis, values of the residual stresses and the Young's moduli in the films are derived, and found to be consistent with previous values deduced from curvature radius measurements or other mechanical test methods, as functions of the deposition conditions. Decohesion of the films from their substrates is easily observed on the W / SiO2 / Si membranes, and the film / sublayer interfacial fracture energy is estimated about 1 J/m2. This energy increases when the sublayer is changed from SiO2 to silicon oxi-nitride and to nitride. The W / Si membranes show a much stronger adhesion than the abovementioned ones and could not be debonded before bursting.
Transversal Type Piezoelectric Resonator Using ZnO Thin Film on Micro-Fabricated Elinver (Fe-Ni-Cr-Ti) Alloy
Authors: Yoshino Y. 
Published: April 2011

AbstractA transversal type 3.58MHz piezoelectric resonator has been fabricated using piezoelectric ZnO thin film on ELINVER (Fe-Ni-Cr-Ti ) alloy. The ZnO/ELINVER structure piezoelectric resonator has been designed to have 2 ppm temperature coefficient of frequency (TCF) per degree from -20 degrees to 80 degrees centigrade. The temperature coefficient of ELINVER alloy can be controlled to cancel the TCF of ZnO thin film by heat annealing. The ZnO thin film on ELINVER alloy shows c-axis orientation. The c-axis orientation of the ZnO thin film is strongly influenced by the surface roughness of the ELINVER alloy. The wet etching process has been adopted to shape the resonator made from ELINVER alloy substrate. The cross section of the resonator is a structure tapered about 10 degrees, created using different sized photo masks on each side of the ELINVER surface. The tapered cross section of the transversal type resonator greatly improves the frequency characteristics of the resonator. The electrical characteristics of the resonator after the improvement include a resonance frequency of 3.58MHz trimmed by a YAG laser, and resonance resistance of about 200 Ω. The temperature coefficient of frequency is about 1.5 ppm per degree at a temperature range of-20 degrees to 80 degrees centigrade.
Application of Energy-Filtering Transmission Electron Microscopy on Advanced IC Device Processing
Authors: Yin K. M. , Chang L. , Chen F. R. , Kai J. J. , Chang H. L. 
Published: April 2011

AbstractEnergy-filtering TEM is applied to characterize the microstructures in ULSI devices. Three cases are shown for EFTEM applications: interfacial reactions in Al metallization, phase identification after arcing in Al metallization, and ONO structure.
A Study of Substrate Orientation Dependence of the Solid-Phase Epitaxial Growth of Amorphised GaAs
Authors: Belay K. B. , Llewellyn D. J. , Ridgway M. C. 
Published: April 2011

AbstractIn-situ transmission electron microscopy (TEM) has been utilized in conjunction with conventional ex-situ Rutherford backscattering spectrometry and channeling (RBS/C), in-situ time resolved reflectivity (TRR) and ex-situ TEM to study the influence of substrate orientation on the solid-phase epitaxial growth (SPEG) of amorphised GaAs. A thin amorphous layer was produced on semi-insulating (100), (110) and (111) GaAs substrates by ion implantation of 190 and 200 keV Ga and As ions, respectively, to a total dose of 1e14/cm2. During implantation, substrates were maintained at liquid nitrogen temperature. In-situ annealing at ∼260°C was performed in the electron microscope and the data obtained was quantitatively analysed. It has been demonstrated that the non-planarity of the crystalline-amorphous (c/a)-interface was greatest for the (111) substrate orientation and least for the (110) substrate orientation. The roughness was measured in terms of the length of the a/c-interface in given window as a function of depth on a frame captured from the recorded video of the in-situ TEM experiments. The roughness of the c/a-interface was determined by the size of the angle subtended by the microtwins with respect to the interface on ex-situ TEM cross-sectional micrographs. The angle was both calculated and measured and was the largest in the case of (111) plane. The twinned fraction as a function of orientation, was calculated in terms of the disorder measured from the RBS/C and it was greatest for the (111) orientation.
Anisotropy of NH4Ap Crystal X-Ray Susceptibility for Bragg Reflection Near Ck Absorption Edge
Authors: Okotrub A. V. , Belikova G. S. , Turskaya T. N. , Mazalov L. N. 
Published: April 2011

ABSTRACTBragg reflection (001) of high-quality crystal of ammonium acid phthalate (2d = 52.28 A˚) is investigated in the region of CK absorption edge. First order reflection for this crystal is forbidden. Due to anisotropic additions, it appears only near CK edge. Two-crystal optical scheme was used for the measurement of the crystal reflectivity. As shown, the change of crystal azimuth in X-ray spectrometer leads to ability to control the resolution. Rotation effects of X-ray beam polarization on 90° angle is considered for the forbidden reflection.
Maximum at ALS: A Powerful Tool to Investigate Open Problems in Micro and Optoelectronics
Authors: Lorusso G. F. , Solak H. , Singh S. , Batson P. J. , Underwood J. H. , Cerrina F. 
Published: April 2011

ABSTRACTWe present recent results obtained by MAXIMUM at the Advanced Light Source (ALS), at the Lawrence Berkeley National Laboratory. MAXIMUM is a scanning photoemission microscope, based on a multilayer coated Schwarzschild objective. An electron energy analyzer collects the emitted photoelectrons to form an image as the sample itself is scanned. The microscope has been purposely designed to take advantage of the high brightness of the third generation synchrotron radiation sources, and it installation at ALS has been recently completed. The spatial resolution of 100 nm and the spectral resolution of 200 meV make our instrument an extremely interesting tool to investigate current problems in opto- and microelectronics. In order to illustrate the potential of MAXIMUM in these fields, we report new results obtained by studying the electromigration in Al-Cu lines and the Al segregation in AIGaN thin films.
Synchrotron Radiation Diffraction Imaging Study of the Magnetoacoustically Induced X-Ray Focusing Effect in FeBO3
Authors: Matsouli I. , Kvardakov V. V. , Espeso J. I. , Chabert L. , Baruchel J. 
Published: April 2011

ABSTRACTSynchrotron radiation diffraction imaging (‘topography’) was used at the ESRF to visualize ultrasonic standing waves in a magnetoacoustically excited FeBO3 crystal. Images were recorded at long sample-to-film distances (up to 1.5 m) without substantial loss of resolution. The resonant patterns reveal that the crystal acts as a pulsed X-ray focusing lens and strongly depend on both the amplitude of the magnetic field and the sample-to-detector distance. Different resonant frequencies can also lead to more complicated images due to interference effects of several vibrating modes present in the crystal. A model is proposed followed by a numerical integration which predicts the focusing of the X-ray beam and demonstrates the agreement between theory and experiment. This effect could be used to simultaneously monochromatize and focus the X-ray beam.
X-Ray Diffuse Scattering Investigation of Defects in Ion Implanted and Annealed Silicon
Authors: Chang C. H. , Beck U. , Metzger T. H. , Patel J. R. 
Published: April 2011

ABSTRACTTo characterize the point defects and point defect clusters introduced by ion implantation and annealing, we have used grazing incidence x-rays to measure the diffuse scattering in the tails of Bragg peaks (Huang Scattering). An analysis of the diffuse scattered intensity will allow us to characterize the nature of point defects or defect clusters introduced by ion implantation. We have also observed unexpected satellite peaks in the diffuse scattered tails. Possible causes for the occurrence of the peaks will be discussed.
Pulsed Laser Deposition of (Ba,Sr)TiO3 Ferroelectric thin Films
Authors: Horwitz J.S. , Chang W. , Carter A.C. , Pond J.M. , Kirchoefer S.W. , Chrisey D.B. , Stroud R.M. , Levy J. , Hubert C. 
Published: April 2011

AbstractSingle phase, (100) oriented Ba0.5Sr0.5TiO3 (BST) thin films have been deposited onto (100) LaAlO3, SrTiO3, and MgO substrates using pulsed laser deposition (PLD). Interdigitated capacitors patterned on top of the ferroelectric film have been used to measure the dielectric constant and dissipation factor of these films as a function of DC bias and temperature at 1 MHz and as a function of DC bias and frequency (1 to 20 GHz) at room temperature. At room temperature, the capacitance can be reduced by as much as a factor of 4 using an electric field of ≤ 80 kV/cm. The dielectric properties (% tuning and dielectric loss) of the ferroelectric film is sensitive to both the deposition and post processing conditions. Optical imaging of the ferroelectric films using confocal scanning optical microscopy (CSOM) shows reproducible polarization fluctuations over sub-micrometer length scales. Dielectric loss in the ferroelectric film is reduced through a combination of post deposition processing and donor/acceptor doping of the films. A zero field tan5 = 0.01 - 0.005 has been measured for BST films which show significant tuning at microwave frequencies.