bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Mo Crystallinity on Diffusion through the Si-on-Mo Interface in EUV Multilayer Systems
Authors: Bruijn S. , van de Kruijs R.W.E. , Yakshin A.E. , Bijkerk F.
Published: March 2009

Thermally induced diffusion through the Si-on-Mo interface of multilayers with either
amorphous or polycrystalline Mo layers has been investigated using grazing incidence and wide angle
x-ray reflectometry. Diffusion through the Mo-on-Si interface was reduced by applying a diffusion
barrier, allowing us to probe the diffusion at the opposite, Si-on-Mo interface.We found that diffusion
through this interface is much slower for polycrystalline Mo than for amorphous Mo layers. The
reason for this difference might be the larger defect concentration in amorphous Mo as compared to
crystalline Mo.
Elastic Behavior of the Ti-13Nb-13Zr Alloy Obtained by Anelastic Spectroscopy
Authors: Florêncio Odila , Silva Paulo Sergio , Ribeiro Rosane , Muñoz Chaves Javier Andres , Sá F.H. , Melo Fábio X. , Schneider Sandra G.
Published: March 2009

Measurements of anelastic relaxation (internal friction and frequency) as a function of temperature were carried out in samples of Ti-13Nb-13Zr using two experimental apparatus: Flexural Vibration of the first tone of samples in Acoustic Elastometer System (Vibran Technology®) operating in a kilohertz bandwidth, and Torsional Vibration of the samples in Kê-type Torsion Pendulum operating in a hertz bandwidth. Experimental spectra of anelastic relaxation were determined in the temperature range from 300 K to 450 K for a heating rate of 1K/min under pressure of 10-5 Torr, in both apparatus. The results show a relaxation structure strongly dependent on the microstructure of the material. The dynamical elastic modulus (E) of Ti-13Nb-13Zr alloy can be determined by flexural vibrations by frequency (f) measurements (f  E1/2). The anelastic relaxation spectrum of Ti-13Nb-13Zr alloy was a function of temperature obtained by torsional vibrations, not revealing the presence of interstitial solutes in solid solution in the temperature range of measurements.
Effect of Polymeric Milling Media on the Mechanosynthesis and Structural Properties of Nanocrystalline Hydroxyapatite
Authors: Shokuhfar Ali , Nasiri-Tabrizi Bahman , Gashti Omid , Ebrahimi-Kahrizsangi Reza
Published: March 2009

Mechanochemical process in polymeric vials has been carried out successfully to produce nanocrystalline hydroxyapatite (HAp) through two different reactions R1 and R2. Morphological properties and structural evaluation of obtained materials are studied by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM). The obtained data show that the increase in milling time leads the increasing in lattice strain and decreasing in crystallite size. The average crystallite size of HAp is below 20 and 23 nm for R1 and R2 reactions, respectively. Based on XRD patterns and SEM/TEM micrographs, the possible formation mechanism of nanocrystalline hydroxyapatite by mechanochemical process in polymeric milling media is confirmed. Final results indicate that the nanocrystalline hydroxyapatite with low chemically stable contaminations and suitable morphology can be produced in Polyamide6 vials similar to stainless steel vials, therefore it seems that using polymeric vials could lead to a new way for the mass production of nanocrystalline hydroxyapatite with high performance, low contamination and cost and also suitable morphology.
An Upper Bound Solution Analysis of Equal Channel Angular Pressing
Authors: Wei Wei , Chen Guang
Published: March 2009

The purpose of this study is to obtain an upper bound solution of ECAP at 0 = ψ and
φ=90 deg, which aims at analysis of the relations between ECAP upper bound pressure and the die angles of φ and ψ. The results show that the value of pressing load and the equivalent strain, e ε , decreases as the angle ψ increases at φ=90 deg, but the equivalent strain, e ε , decreases rapidly and no less than 0.90. The measured maximum load required for ECAP is in good agreement with the values obtained from the upper bound solution.
Hydrothermal Synthesis of Zn-Al-O Composite Nanorods
Authors: Shen S.C. , Hidajat K. , Yu L.E. , Kawi S.
Published: March 2009

This paper reported that nanorods of Zn-Al-O composites could be synthesized through hydrothermal process and followed by solid reaction during calcination. The nanorods composites showed high thermal stability up to 900 °C without observed sintering between individual nanoparticles.
Synthesis and Characterization of Nano-Composite Lead-Free Solder
Authors: Lin D.C. , Kuo C.Y. , Srivatsan T.S. , Petraroli M. , Wang G.X.
Published: March 2009

A series of experiments conducted on a lead-free eutectic solder (Sn-3.5%Ag) have shown that addition of trace amounts of nanometer-sized particles does have an influence on mechanical properties of materials. In this study, three different types of nanoparticles (copper, nickel and iron) were chosen as the reinforcing candidate. For each particulate reinforcement the reflow process was performed under identical cooling conditions. Addition of trace amounts of nano-particles alters the kinetics governing solidification of the composite solder paste while concurrently exerting an influence on microstructural development, particularly the formation and presence of second phases in the solidified end product. The nano-sized powder particle-reinforced composite solder revealed an increase in microhardness compared to the unreinforced monolithic counterpart.
Creation of High Performance Mg Based Composite Containing Nano-Size Al2O3 Particulates as Reinforcement
Authors: Hassan S.F. , Gupta Manoj
Published: March 2009

Magnesium based composite with 2.5 weight percentage of nano-sized Al2O3 particulates reinforcement was fabricated using powder metallurgy technique. Al2O3 particulates with an equivalent size of 50-nm were used as reinforcement. Microstructural characterization of the materials revealed recrystallization and grain refinement due to the presence of nano-Al2O3. Mechanical properties characterization revealed that the presence of nano-Al2O3 particulates as
reinforcement lead to a significant increase in hardness, elastic modulus, 0.2% yield strength and UTS and ductility of pure magnesium. The results revealed that the specific tensile properties of these materials are superior when compared to high strength magnesium alloy AZ91 reinforced with much higher weight percentage of SiC. An attempt is made in the present study to correlate the effect of nano-sized Al2O3 particulates as reinforcement with the microstructural and mechanical
properties of magnesium.
Mechanical Properties of ECAE Nanocrystalline Copper and Nickel
Authors: Bansal S. , Saxena A.M. , Hartwig T. , Tummala Rao R.
Published: March 2009

Bulk nanocrystalline copper and nickel (average grain size ~ 50 nm) with high purity and density were synthesized by equichannel angular extrusion (ECAE). Both nanohardness and microhardness measurements revealed a significant increase in hardness of the bulk sample. The tensile strength of these materials has been found to be 5-6 times higher than conventional forms and our experiments show that Cu is extremely stable up to temperatures of 100 oC and Ni to temperatures of 250 oC. The fracture toughness, measured by the value of JIC for nc-copper and nickel have been found to be 21.66 KJ/m2 and 12.13 KJ/m2, respectively which are high for these strength levels.
Microstructure of Nanocrystalline Nickel Deposit Pulse-Plated on Depleted Uranium Surface
Authors: Wang Qing Feng , Zhang Peng Cheng , Wang Xiao Hong , Ren Da Peng , Lang Ding Mu , Zhang Yan Zhi
Published: March 2009

Microstructure of nickel deposit ,which was prepared with pulse-plating technology on depleted uranium surface, has been studied by X-ray diffractometry（XRD）,Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The results indicate that the crystallographic structure of the deposit is face centered cubic; the deposit has a highly preferred orientation of (200), the relative orientation density of (200) is 3.44; the average grain size is about 45.5nm. The deposit is fine and has multi-crystal nature as well as crystallographic defects as dislocation, stacking and twin. It’s feasible to prepare nanocrystalline nickel deposit on depleted uranium surface with pulse plating technology.
Effect of Pretreatment of Synthetic and Natural Carbons as Starting Materials for Carbon Nanotubes
Authors: Buang N. , Aziz M. , Sanip S. , Tee J.C. , Abidin Z.H.Z , Ismail Ahmad Faris
Published: March 2009

Carbon are well known as active materials for energy storage and conversion. They are preferred because carbon materials have high electrical conductivity, low cost, high surface area, porosity, formability and possess good chemical and electrochemical resistivity. The most recently discovered novel carbon material is the carbon nanotubes, having unique geometrical structure and stable mechanical and chemical properties. The starting materials for carbon nanotubes production widely used are high purity graphite. Thus, two types of carbons were studied and thermal treatments were conducted at temperatures ranging from 600 – 800 °C for several hours. The effect of the pretreatment upon their morphology and surface area were looked into. It was found that significant changes occurred for the natural carbons while the synthetic carbons showed little or no changes at the particular temperature range. The thermal treatment has resulted in the exposure of fresh edge planes and microparticles as well as changes in the specific surface area and enhances their adsorption properties.
A Study of the Effect of Polymer Matrix on the Ultrasonic Propagation in Silver Nanoparticles
Authors: Rajagopalan S. , Sharma S.J. , Nanotkar V.Y.
Published: March 2009

In the present work, ultrasonic velocity measurements have been carried out in solutions of silver nanoparticles in the polymer matrix of poly(sodium, 4-styrene
sulphonate) using Sing-Around technique, operated at 2 MHz.. The ultrasonic velocity of propagation shows an abnormal behaviour, indicating the existence of the phase separations in nano-colloidal solution. The effect of polymer is observed to be predominant in the phase separation at the lower concentrations of polymer in the mixture. At higher concentrations of the polymer in the mixture the phase separation seems to subside at higher temperature.
Gold Nanoparticles on Polymeric Micro Beads: A One-Pot Synthesis and Characterization by X-Ray Absorption Near Edge Structure (XANES) Spectroscopy
Authors: Kumar Challa S.S.R. , Aghasyan Mher , Modrow Hartwig , Hormes Josef , Tittsworth Rolland
Published: March 2009

Cetyl trimethyl ammonium bromide (CTAB) stabilized gold(III) salt in chloroform was reduced using NaBH4 in the presence of commercially available methanethiol-polyphoResinTM to obtain polystyrene micro beads with gold nanoparticles on their surface. X-ray Absorption Near Edge Spectra (XANES) of Au and S revealed S-Au bonding state. TEM studies coupled with Selected Area Electron Diffraction(SAED) patterns revealed the morphology of the Au nanoparticles on the surface of the micro beads.
Investigation into the Effects of Transformer Oil on Fluoro Poly(ether imide)s and their Nanocomposites Films
Authors: Sarathi R. , Deepa S. , Mishra A. , Vora Rohitkumar H.
Published: March 2009

In the present work, the fluoro polyimide films were aged in the transformer oil and the characteristic changes in the film and the transformer oil are analyzed through physico-chemical diagnostic studies. The WAXD and FTIR studies showed that no characteristic change in the material due to thermal aging of the material. The FTIR spectra of the corona aged specimen indicate the formation of new functional groups. The fluorescence spectra of the aged transformer oil suggest
dissolvement of heavy ions in the clay material.
Investigation of Amorphous Silicon-Carbon Films Deposited by Filtered Vacuum Cathodic Arc
Authors: Zhang P. , Tan W.M. , Tay B.K.
Published: March 2009

Amorphous silicon-carbon films have been successfully deposited by the filtered cathodic vacuum arc techniques. One set of films was deposited from varying silicon-carbon composition in the targets and another set of films was deposited at different various substrate bias voltages from 5 at.% silicon target. The properties of the film were investigated by using atomic force microscopy (AFM), Raman spectroscopy, x-ray photoelectron spectroscopy (XPS) and contact angle
measurement.
The first set of the samples exhibit atomic smooth surface morphology with RMS roughness below 0.26 nm. The silicon composition in the films determined by XPS varies from 0 to 61 at.%. The Raman results show that at low silicon composition, the G peak position of C-C bond shifts to a low
wavenumber, that demonstrates the silicon atom predominantly substitutes for the carbon atom. As the silicon composition increase, the G peak disappeared and a strong broad peak corresponding to the amorphous silicon carbide cluster appears around 800 cm-1.
For the second set, the Raman results show the ID/IG ratio increased from 0.24 to 0.67 with using the high bias voltages during the deposition. That indicates the disorder of C-C bond within the films increased. While, both the silicon concentration in the films and contact angles remain relatively constant with the change of bias voltage.
Scalable Production of Carbon Encapsulated Ni Nanoparticles by Water Arc Discharge: Structural and Magnetic Properties
Authors: Ang K.H. , Alexandrou I. , Mathur N.D. , Lacerda R. , Bu I.Y.Y. , Amaratunga G. , Haq S.
Published: March 2009

An electric arc discharge in de-ionised water between a solid graphite cathode and an anode made by compressing Ni and C containing powders in a mass ratio of Ni:C = 7:3 was used here to prepare carbon encapsulated Ni nanoparticles in the form of powder suspended in water. The morphology of the produced material was analysed using high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The magnetic properties of the samples were determined using a Princeton vibrating sample magnetometer (VSM). Collection of the powder
produced from different depths in the water container has proved to be an effective method for obtaining samples with narrow particle size distribution. Further material purification by dry NH4 plasma etching was used to remove the amorphous carbon content of the samples. XRD and HRTEM analysis showed that the material synthesized is fcc Ni particles with mean particle size ranging from 14 to 30 nm encapsulated in 2 to 5 graphitic cages. The data suggests that the process
reported has the ability to mass-produce carbon encapsulated ferromagnetic nanoparticles with desired particle size distribution, and hence with controlled size-dependent magnetic properties.
Softmagnetic Nanocomposite with Silicon Polymer Matrix and Powdered Co68Fe4Mo1Si13,5B13,5
Authors: Dobrzański Leszek Adam , Nowosielski Ryszard , Wysłocki J.J. , Przybył A. , Konieczny J.
Published: March 2009

Structure, magnetic and mechanical properties of the nanocrystalline composite material of the SILAME® type were tested. The composite material was obtained by solidification of the nanocrystalline powder obtained in the high energy grinding of the initially crystallized Co68Fe4Mo1Si13,5B13,5 amorphous strip with the silicon polymer. The metallic powder was mixed with the silicon polymer in a different weight ratio and next the effect of Co68Fe4Mo1Si13,5B13,5 powder weight ratio on the magnetic and physical properties of the composite was investigated.
A High-Resolution Amperometric Acetylcholine Sensor Based on Nano-Assembled Carbon Nanotube and Acetylcholinesterase Thin Films
Authors: Xue Wei , Cui Tianhong
Published: March 2009

We demonstrate a carbon nanotube based high-resolution biosensor for acetylcholine sensing. Carbon nanotubes are deposited on a silicon wafer in a repeated fashion with layer-by-layer nano self-assembly technique. With nano-assembled acetylcholinesterase molecules on the surface, the carbon nanotube biosensor is capable of detecting acetylcholine at an ultra-low concentration of 100 pM. The sensitivity of the acetylcholine sensor is measured as 7.2 µA/decade. The real-time measurement shows the response time of the biosensor is approximately 6 sec. Both the carbon nanotube film and the acetylcholinesterase film are crucial in the sensing process. Due to its high resolution, fast response, small size, and low cost, the carbon nanotube biosensor has tremendous potential for applications in medical research and clinical diagnosis.
Hydrogen Bonding: A Bottom-Up Approach for the Synthesis of Films Composed of Gold Nanoparticles
Authors: Chirea Mariana , Pereira Carlos M. , Silva Fernando
Published: March 2009

Citrate gold nanoparticles of 13.5 nm average diameters have been synthesized by
Turkevich method and further functionalized by place exchange reaction using mercaptosuccinic
acid (MSA), 1,4-benezenedimethanethiol (1,4BDMT) or mercaptoundecanoic acid (MUA) as the
incoming ligands. In the first case, the functionalization of the gold clusters with MSA yielded
solution of blue color and large aggregates on carbon grids. Moreover, after filtration and drying,
any film formed by hydrogen bonding, could not be removed from the filter, being embedded into
the filter texture. The second ligand used for the place exchange reaction, the 1,4BDMT, determined
the change of the solution color from red to dark purple, and generation of a purple powder but no
film formation. In the third case, the purification and drying of the MUA functionalized gold
clusters yielded films of purple color with homogenous composition, robustness, soft topographies
and remarkable optical properties which were dependent on their thicknesses. The Au-MUA NP
films obtained are new, being generated by hydrogen bonding and having features which makes
them very attractive for the fabrication of optoelectronic devices. The long alkyl chained thiol
proved to be the adequate ligand for film synthesis.
Surface Engineering of CuIn0.75Ga0.25Se2 Thin Films
Authors: Ahmed E. , Ahmed Waqar
Published: March 2009

In this paper the effects of post-deposition annealing followed by hydrogen ionimplantation
on the properties of CuIn0.75Ga0.25Se2 thin films have been investigated. The samples
were grown by flash evaporation onto glass substrates heated at temperature between room
temperature and 200°C. Selected samples were subsequently processed under several sets of
conditions, including vacuum, selenium, inert (argon) and forming gas (a 9:1 mixture of N2:H2)
followed by hydrogen ion-implantation. A high resolution near-infrared photoacoustic spectrometer of
the gas-microphone type was used for room temperature analysis of non-radiative defect levels in the
as-grown, annealed and hydrogen implanted thin films. The absorption coefficient has been derived
from the PA spectra to determine the gap energy and to establish the activation energies for several
defect-related energy levels. The changes observed in the PA spectra following annealing and ionimplantation
has been directly correlated with the compositional and structural properties of the
samples.
Metallic Tin-Filling Effects on Carbon Nanotubes Revealed by Atomically Resolved Spectro-Microscopies
Authors: Maccallini E. , Kalantzopoulos G. , Tsoufis T. , Agostino R.G. , Chiarello G. , Formoso V. , Caruso T. , Policicchio A. , Gournis D. , Colavita E.
Published: March 2009

The identification of features in the Local Density of States (LDOS) of carbon nanotubes
(CNTs) obtained by Scanning Tunneling Spectroscopy (STS) is of great importance in order to
understand their properties. In this work, Single- and Multi-Wall Carbon Nanotubes are compared
with Multi-Wall CNTs filled with tin nanowires (Sn@CNTs) in order to investigate the effect on
morphological and electronic properties of the CNTs metallic filling. The LDOS of CNTs, together
with topology changes, is investigated by using spatially resolved STM/STS at room temperature
and in air and compared to the LDOS of highly oriented pyrolitic graphite (HOPG). The LDOS of
CNTs is dominated from different electronic states filling the C 2pσ-2pσ* band gap. The
appearance of those states is linked to the diameter and the defects of the CNTs. In fact, Snnanowires
encapsulation induces changes in the structure of the CNTs and the appearance of
electronic states in the LDOS inside the band gap. A more extensive description of the samples is
obtained depicting the morphological features and the vibrational structure on wider areas using
Scanning Electron Microscopy (SEM) and Raman spectroscopy, respectively.
Energy Band Gap Studies of CdS Nanomaterials
Authors: Patidar Dinu , Rathore K.S. , Saxena N.S. , Sharma Kananbala , Sharma T.P.
Published: March 2009

The CdS nanoparticles of different sizes are synthesized by a simple chemical method. Here, CdS nanoparticles are grown through the reaction of solution of different concentration of CdCl2 with H2S. X-ray diffraction pattern confirms nano nature of CdS and has been used to determine the size of particle. Optical absorption spectroscopy is used to measure the energy band gap of these nanomaterials by using Tauc relation. Energy band gap ranging between 3.12 eV to 2.47 eV have been obtained for the samples containing the nanoparticles in the range of 2.3 to 6.0 nm size. A correlation between the band gap and size of the nanoparticles is also established.
Aspect Ratio Evaluation of Carbon Nanotubes Grown on Calcium Carbonate Substrate for Different Temperatures and Precursor Flow Times
Authors: Pati K.N. , Solanki Chetan S.
Published: March 2009

Carbon Nanotubes (CNTs) are excellent material with a variety of physical, electrical, and mechanical properties. The average aspect ratio is evaluated for samples synthesized at different temperature and time of precursor flow. The experiments were conducted on calcium carbonate (CaCO3) substrate with iron-cobalt (Fe-Co) as a catalyst. Acetylene (C2H2) was used as a precursor gas and argon (Ar) as a carrier gas. The experiments were performed at temperatures ranging from 600 0C to 900 0C in step of 100 0C with time of precursor flow varying from 15 minutes to 75 minutes in the step of 15 minutes. The partial pressure of C2H2 and Ar kept constant during synthesis of CNT. The mass flow rate of C2H2 and Ar were 2 liters/hour and 60 liters/hour respectively during synthesis of CNT. The characterization of CNT was done with SEM, EDX, and TEM microscopes. Average aspect ratio of CNT is estimated using image analysis software. Most of nanotubes grown present an average diameter of 40 nm. The minimum and maximum diameter found are12.5 nm and 106 nm respectively. It is observed that average aspect ratio ranges from 25 to 58.
Study of the Silanization Process in CNFs: Time, Temperature, Silane Type and Concentration Influence
Authors: Palencia Cristina , Rubio F. , Merino Cesar , Rubio Juan , Oteo J.L.
Published: March 2009

Functionalization of CNFs with silane coupling agents (SCAs) has been studied in this work. APS silane has been used in order to study the influence of temperature and reaction time on the silanization process. Thermal analysis and surface area measurements have revealed that reaction times higher than 1 min. and temperature reaction higher than 25°C do not increase the amount of adsorbed silane on CNFs surface. Silanization process carried with different SCAs (APS, AMO, DMO and GMO) has allowed the study of the concentration and silane structure influence. It has been observed that differences in SCA adsorption are related to the silane structure. Aminosilanes APS and AMO show a very similar behaviour because they have the same functional group. However, the diaminosilane DMO shows lower interaction with CNFs surface due to the length of the diamine chain, that avoid further silane adsorption on the coated CNFs surface. The epoxysilane GMO shows a similar behaviour to other SCAs at low concentrations, while for high silane concentrations epoxysilane GMO forms multilayers.
Gold Particle Size Determination on Au/TiO2-CeO2 Catalysts by Means of Carbon Monoxide, Hydrogen Chemisorption and Transmission Electron Microscopy
Authors: Guzmán C. , Del Angel Gloria , Gómez Ricardo , Galindo F. , Zanella R. , Torres G. , Ángeles-Chávez C. , Fierro J.L.G.
Published: March 2009

Au/TiO2 and Au/TiO2-CeO2 catalysts were prepared by the sol-gel method and carbon monoxide, hydrogen chemisorption and TEM spectroscopy have been exploited to determine the size of gold particles. The gold nanoparticles (8.1 to 2.1 nm) were deposited by using the deposition-precipitation method. The XRD characterization shows the presence of anatase as the TiO2 crystalline phase; while by XPS spectroscopy, the presence of Au°, Au2O3, Ce3+ and Ce4+ species co-existing in the Au/TiO2-CeO2 catalysts is shown. The characterizations by TPD-CO as well as by TPD-H2 (temperature programmed desorption) showed that on catalysts containing cerium, the gold particle size can be determined with great accuracy by using these chemisorption methods. The gold particle size calculated from either the CO or H2 thermodesorption values is in good agreement with that obtained by High Resolution Transmission Electron Microscopy (HRTEM) and Scanning Transmission Electron Microscopy (STEM) analyses. It was proposed that the TPD-CO and/or TPD-H2 techniques could be helpful for the characterization of the gold particles by TEM; especially when the high contrast in the pictures of the supports containing CeO2 prevents the particle size from being determined.
Density Functional Study of the Structural Properties of Copper Iodide: LDA vs GGA Calculations
Authors: Hernández-Cocoletzi Heribert , Cocoletzi Gregorio H. , Rivas-Silva J.F. , Flores A. , Takeuchi Noboru
Published: March 2009

We have performed first principles total energy calculations to investigate the structural properties of copper iodide (CuI) in its sodium chloride, cesium chloride, zincblende and wurtzite structures. Calculations are done using the density functional theory. We employ the full potential linearized augmented plane wave method as implemented in the wien2k code. The exchange and correlation potential energies are treated in the generalized gradient approximation (GGA), and the local density approximation (LDA). Optical absorption experiments and x-ray diffraction measurements have shown that zincblende is the ground state of CuI. Our calculations find that in the GGA formalism wurtzite and zincblende have similar total energies, while in the LDA formalism the lowest minimum corresponds to zincblende. Results show that the energy difference between the wurtzite and the zincblende structures, as calculated within the GGA formalism is 2 meV, and within the LDA formalism, is 31 meV. These results may suggest a coexistence of both wurtzite and zincblende structures in the ground state of CuI. Structural parameters are correctly reproduced by the GGA calculations. We obtain that under the application of external pressure the atomic configuration may transform into the NaCl structure. At higher pressures it is possible to have a phase transition to the CsCl geometry.
Investigation of the Microstructure of SiC-Zn Nanocomposites by Microscopic Methods: SEM, AFM and TEM
Authors: Swiderska-Sroda Anna , Kozubowski J.A. , Maranda-Niedbala A. , Grzanka Ewa , Palosz Bogdan F. , Presz A. , Gierlotka Stanislaw , Stelmakh Svetlana , Kalisz Grzegorz , Herlin-Boime Nathalie , Lathe C.
Published: March 2009

SiC-Zn nanocomposites with about 20% volume fraction of metal were fabricated by
infiltration process under the pressure of 2-8 GPa and at the temperature of 400_1000oC. SiC nanopowders used in the experiments formed loosely agglomerated chains of single crystal nanoparticles. The dimension of the agglomerates was in the micrometer range, the mean grain size was up to tens of nanometers. Microstructural investigations of the nanocomposites were performed
at a different resolution levels using scanning, transmission electron microscopy and atomic force microscopy techniques (SEM, TEM, AFM, respectively). SEM observations indicate a presence of nano-dispersed, uniform (on the micrometer scale) mixture of two phases. TEM observations show that distribution of SiC and Zn nanocrystallites is uniform on the nanometer scale. High-resolution TEM images demonstrate an existence of thin (on the order of tens of Angstroms) Zn layers
separating SiC grains. AFM images of the mechanically polished samples show a smooth surface with the roughness on the order of the SiC grain size (10-30 nm). After ion etching of some samples the AFM topographs show surface irregularities: periodically spaced hillocks 50-100 nm in height. The size of the SiC grains remains equal to that of the initial powder crystallites. The size of the Zn grains varies in the range of 20-100 nm depending on the initial SiC grain size and the composite fabrication conditions.
Particle Adhesion on Tool Kit Part: Case Study for Ceramic Material
Authors: Blanc S. , Préauchat B. , Veillerot Marc
Published: March 2009

In the first part of this paper, the main steps to consider in the build up of a particle measurement method on tool kit parts with a DIW/US protocol have been described. Through that methodology, measurement protocols achieving compromises between cleaning efficiency and minimal substrate erosion can be set up for tool parts. The adhesion problem of particles on a real rough substrate is then discussed solving DLVO theory equations considering physical and chemical analysis on surface and residual particles.
Cu Spin Cleaning Evaluation by SOR X-Ray Fluorescence Analysis
Authors: Hayashi Hidekazu , Tsugane Ken , Kagoshima Yasushi , Koyama Takahisa , Watanabe Masaharu , Kozuki Yasushi
Published: March 2009

Cu contamination control is critically important in Cu interconnect device manufacturing lines. The frontside gas protected spin cleaning enables the effective removal of the Cu contaminant from the backside and bevel of a wafer. A small area on the bevel was measured for cleaning efficiency using SOR (Synchrotron Orbital Radiation) X-ray fluorescence. The atomic level Cu removal was detected
on the bevel surface with the barrier metal Ta existing wafers. The high energy SOR X-ray analysis makes it possible to measure the Cu contamination, where conventional methods do not work.
High-k Gate Dielectrics on Silicon and Germanium: Impact of Surface Preparation
Authors: Beverina Alessio , Frank M.M. , Shang H. , Rivillon S. , Amy F. , Hsueh C.L. , Paruchuri V.K. , Mo R.T. , Copel M. , Gusev E.P. , Gribelyuk M.A. , Chabal Y.J.
Published: March 2009

We review the impact of semiconductor surface preparation on the performance of metal-oxidesemiconductor field-effect transistor (MOSFET) gate stacks. We discuss high-permittivity dielectrics such as hafnium oxide and aluminum oxide on silicon and on the high carrier mobility substrate germanium. On Si, scaling of the gate stack is the prime concern. On Ge, fundamental issues of chemical and electrical passivation need to be resolved. Surface treatments considered include oxidation, nitridation, hydrogenation, chlorination, and organic functionalization.
Effects of Patterns on Corrosion in Cu CMP
Authors: Han Ja Hyung , Koo Ja Eung , Hong Duk Ho , Park Byung Lyul , Kim Seong Il , Cho In-Soo , Eom Dae Hong , Park Jin Goo , Busnaina Ahmed A.
Published: March 2009

Corrosion on specific Cu patterns was evaluated during Cu CMP. The corrosion was observed at isolated patterns and outer edge area of pad surrounded by oxide field after polishing and showed dependency on process. Two different commercial slurries were chosen and used for polishing after characterizing electrochemical and frictional properties. Stress simulations were conducted on these patterns. Higher stress was calculated on these patterns. The process temperature and friction behavior of Cu affected the magnitude of corrosion on Cu on these patterns.
Texture Control in Manufacturing of ULSI Devices
Authors: Kozaczek Kris J.
Published: March 2009

The rapid adoption of damascene copper processing has brought about an increased need to understand and control microstructure in the barrier, seed and electroplated copper layers during manufacture. We will discuss an in-line, x-ray diffraction based metrology for rapidly characterizing thin film polycrystalline microstructures on 300 mm silicon wafers in terms of crystallographic texture, phase composition, and film thickness. The microstructure control plays an increasingly important role in improving the performance and reliability of ULSI devices that use the damascene copper technology at 0.13-µm node and below. The problems related to delamination, stress voiding, and electromigration failures could be mitigated by the selection of proper materials, processing methods, and manufacturing tools. The optimum process would result in a tailored microstructure of barrier/seed/electroplated copper aggregate. At the same time, the microstructure could be used as an internal sensor, sensitive to process excursions and providing guidance for the corrective actions. The texture and crystallographic phase data can be used as a direct measure of the deposition process in terms of film quality, reproducibility, and stability over time. The spatial distribution of crystallographic texture and phase can be measured on a single wafer in order to check wafer uniformity. More importantly, the same measurements can be carried out at predetermined intervals on wafers from a single deposition tool, and the results used to create a database that can be applied to trend charting and tool qualification. Examples of microstructure control in damascene copper processing include: process development and qualification, process control and stability, deposition tool qualification, and on-line R&D. Examples of texture control will refer to materials and processes typical of damascene copper technology for ULSI. A typical processing route includes the PVD deposition of a barrier layer and copper seed layer, followed by copper electroplate (EP), anneal, and chemical-mechanical planarization (CMP). All the processing steps affect the texture of annealed copper, and therefore affect directly the performance of interconnects.
On the Calculation of the Eshelby Tensor and the Beauty of our Nature
Authors: Matthies Siegfried , Vinel G.W.
Published: March 2009

The calculation of the Eshelby tensor occupies the dominant part of time in modern selfconsistent schemes modeling texture developments. A further time-reduction can be got representing the denominator in the explicit expression of the integrand of the Eshelby integral by finite series, leading to known library integrals. The possibility to get fast converging series depends on the degree of anisotropy of the stiffness tensor C. As universal (any symmetries) parameter, in order to classify the degree of anisotropy of a given C-data set, the variance s0 of the normalized determinant D0(C,r) of the Christoffel matrix is suggested. s0 can exactly be determined without great effort. For typical C-sets time reducing factors in the order of 2 – 8 have been got. Beyond this special result the anisotropy parameter 0 £ s0 < 1 seems to be of general importance. 3d-figures of D0(C,r) show characteristic (and sometimes unexpected ‘beautiful’) individual faces of the elastic properties of monocrystalline or textured polycrystalline substances.
β Microtexture Analysis in Correlation with HCP Textured Regions Observed in a Forged Near Alpha Titanium Alloy
Authors: Bocher Philippe , Jahazi Mohammad , Germain Lionel , Wanjara Priti , Gey Nathalie , Humbert Michel
Published: March 2009

The presence of hcp regions with grains having relatively close orientations has been reported in commercial near alpha titanium billets (IMI 834, Ti 6246, etc). The size of these textured regions (called macrozones) is significantly larger than the average grain size of the microstructure observed after thermomechanical processing. The elongated shape of these large hcp regions suggests that they are eventually related to large prior b grains that pancaked during the ingot break down process. In this contribution, Orientation Image Microscopy was used to study the relationship between the hcp local microtexture heterogeneities and the prior b orientations. Specifically, the orientations of the primary (equiaxed) ap grains and the secondary (lamellar) as colonies produced after the transformation of the b phase were discriminated from OIM maps. Furthermore, from the as inherited OIM map, it was possible to reconstruct the corresponding b OIM map over large regions. The analysis showed that the large hcp macrozones observed in the as
received material are not related to corresponding bcc macrozones. However, within an hcp macrozone, various clusters of b grains with similar orientations can be found. In such coherent regions, randomly orientated b grains were also observed, which could be related to microstructural changes during deformation (continuous dynamic recrystallization) as suggested by hot deformation
results.
The Influence of Texture and GBCD on Stress Corrosion and Intergranular Corrosion in 2024 Aluminum Alloy
Authors: Wu Bao Lin , Shi Ji Hhong , Zhang Yu Dong , Wang Yi Nong , Zuo Liang , Esling Claude
Published: March 2009

The recrystallization texture, grain boundary character distribution (GBCD) and their influence on the stress corrosion cracking and intergranular corrosion of 2024 aluminum alloy were investigated. Results showed that the texture of Specimen A1 is characterized by the retained coldrolling texture; while Specimen A3 has strong recrystallized cube texture and high frequencies of CSL grain boundaries (especially S7), which shows high stress corrosion and intergranular
corrosion resistance.
Effect of the 0.1% Sc Addition on the Texture Development and Mechanical Properties in Al-Zn-Mg-Cu-Mn Alloy
Authors: Park No Jin , Jin S.J. , Jea C.W. , Lim Seong Taek , Lee Yong Yun , Chung Dong-Seok
Published: March 2009

After extrusion, cold rolling and T-6 treatment, microstructure, texture development, and deep drawability of Al-5.09%Zn-1.83%Mg-0.32%Cu-0.25%Mn-alloy with 0.1% Sc are studied. After T-6 treatment, recrystallized equiaxed grains with an average grain size of 1~2㎛ are obtained. During extrusion the very strong <111>-fiber + medium sharp <100>-fiber + weak <210>-fiber texture is developed, which influences the formation of rolling texture. The texture, after 80% cold rolling, can be described by the strong {112}<111>(Cu) + {123}<634>(S) component in the cross section of the extruded rod, the strong b-fiber + weak {110}<001>(Goss) components in the longitudinal section, and the strong {110}<112>(Bs) + weak {001}<100>(Cube) components in the transverse section. The types of rolling texture are not changed after the T-6 treatment, but the maximum density of ODF is higher. The calculated mean r-values, rm, and the planar anisotropy, Dr, are relatively high, which are dependent on the texture.
Dislocation Activity and Slip Analysis Contributing to Grain Boundary Sliding and Damage during Thermomechanical Fatigue in Dual Shear Lead-Free Solder Joint Specimens
Authors: Telang Adwait U. , Bieler Thomas R.
Published: March 2009

To investigate the effect of external loads arising from differential thermal expansion between a substrate and a surface mount component, specimens with a simulated surface mount component (nickel) on a copper substrate having a 1 mm2 joint area and solder thickness of about 100 µm were prepared to induce extrinsic shear in joints undergoing thermomechanical fatigue (TMF) cycling. The specimens were fabricated stress free and later clamped to a copper block to cause a significant reversal in sign of the shear imposed on the solder joint during TMF cycling for 20 minutes at 150°C and 3.5 hr at -15°C. The evolution of surface damage and microstructure was examined using SEM and Orientation Imaging Microscopy (OIM). The joints were almost single crystals. However, the orientations of the tin in each joint is different, leading to different resolved stresses on a given slip system. The joint with the largest resolved shear aligned with the crystal caxis showed the most damage. Low angle tilt boundaries developed, and sliding was observed on boundaries near 7 and 14° that have a coincident site lattice. Schmid factor analysis was carried out in regions that showed ledges or grain boundary sliding. Slip on (110) planes correlated well with some of the ledges.
The Goss Texture Formation in Silicon Steels – Growth Selection or Oriented Nucleation?
Authors: Zaefferer Stefan , Chen Nan
Published: March 2009

The formation of the Goss texture in electrical steels is one of the most distinct phenomena of texture research. Nevertheless, disregarding 60 years of research the mechanisms which let only Goss-oriented grains grow abnormally during a secondary recrystallisation annealing are still not completely understood. The present paper reviews some of the mechanisms of growth selection and oriented nucleation and discusses them in the light of observations made by the authors. We conclude that no mechanism proposed so far is able to explain all experimental observations. This points out the need for the search for a different mechanism.
Texture and Microstructure Imaging by the Moving Area Detector Method
Authors: Preusser Andrea , Klein Helmut , Bunge Hans Joachim
Published: March 2009

Additional to the position of any volume element of a (poly)-crystalline material its crystal orientation must also be known. Both together are described in the six-dimensional orientation-location space. The paper describes the most frequent structures of materials in this space and how these can be imaged with the "Moving Area Detector Method" using hard synchrotron X-rays. This technique is equally well suited for basic reseach in materials science as well as for non-destructive testing of technological parts or even complex structural components.
Microstructure and Texture in Copper Sheets after Reverse and Cross Rolling
Authors: Ostafin M. , Pospiech Jan , Schwarzer Robert A.
Published: March 2009

The objectives of this investigation are structural effects in electrolytic copper sheets which are caused by the change of the direction of rolling. Unidirectional, reverse as well as cross-rolling at 90° respectively at 45° to the precedent rolling direction have been applied down to final deformations as low as 80% reduction in thickness. Texture has been determined by ACOM (Automated Crystal Orientation Measurement, “Automated EBSD”) in the SEM and by X-ray pole figure measurement. The main benefits of ACOM are a high spatial resolution which enables the investigation of texture gradients from the mid plane to the surface of the sheet, and the visualization of the microstructure by crystal orientation mapping. In addition to local texture, statistical distributions of misorientations across grain boundaries and of S grain boundaries have been derived from the individual grain orientation data.
The change of the path of plastic deformation induces a destabilization of the substructure which is formed during the primary step of unidirectional rolling. A distinct change of texture is found depending on the deformation process. In cross rolling, the b fiber changes into the unstable b90 fiber which almost disappears with progressive deformation along the new rolling direction.
Texture and Microstructure Evolution during Cold Swaging and Recrystallization of Oligocrystalline INCOLOY® MA 956
Authors: Hupalo Marcio Ferreira , Padilha Angelo Fernando , Sandim Hugo Ricardo Zschommler
Published: March 2009

Cold swaged and annealed samples of INCOLOY MA 956 (UNS S67956) were investigated using light optical microscopy (LOM), transmission electron microscopy (TEM), X-ray diffraction (XRD), electron backscattered diffraction (EBSD), and Vickers microhardness testing. The as-received oligocrystalline material presented a strong <111>-texture parallel to the longitudinal direction of the bar. This texture results from secondary recrystallization promoted by zone annealing. The microstructure in the deformed state was found to be very inhomogeneous. Deformation bands were observed in all grains. The extent of deformation banding varied from grain to grain in terms of morphology and spacing. The deformation substructures were found to be very different in each grain. A sharp <110>-fiber texture was developed during plastic deformation becoming more pronounced with increasing strain. Intense recovery during annealing has been observed in this alloy. Recrystallization did not change the texture significantly.
Texture Gradient in ECAP Copper Measured by Synchrotron Radiation
Authors: Skrotzki Werner , Scheerbaum N. , Oertel C.G. , Brokmeier Heinz Günter , Suwas Satyam , Tóth László S.
Published: March 2009

Copper of 4N purity was deformed at room temperature by equal channel angular pressing (ECAP) using three passes of route A. The local microstructure and texture were investigated by orientation imaging microscopy and high-energy synchrotron radiation, respectively. The microstructure consists of elongated grains which are inclined to the extrusion direction. The texture is characterized by typical shear components of fcc metals which deviate from their ideal positions. The inclination of the grain long axis and the texture components with respect to the extrusion direction depends on the distance from the top of the extruded bar and changes from pass to pass. Reasons for the texture gradient are discussed.
Strain Localization Observed during Shearing of Some Aluminium Alloys and Texture Softening Predicted by FC Taylor and Advanced Lamel Model
Authors: Hu Xiahua , Gaspérini Monique , van Houtte Paul
Published: March 2009

In-situ SEM shearing tests were performed on samples from the heavily cold rolled (Extrahard) aluminium alloys, where the parallelepiped test sample was cut as to let shear direction (SD) have an angle α with the rolling direction (RD). This shear angle ranges from 0o to 165o with an interval of 15o. These include three heavily cold rolled non heat-treatable aluminium alloys AA1200, AA3004 and AA5182. During these tests, strain localization (macro-shearbands) was bserved. This phenomenon is found to be anisotropic and depends on the angle α. The strain localization or macro-shearbands are believed to be related with strain softening, where the flow stress decreases with strain. According to the crystal plastic theory, the strain softening is considered as resulting from the joint effects of texture and evolution of microstructure, in particular the dislocation patterns. Focusing on texture softening, simple and advanced Taylor type micro-mechanical simulations (Full-constraint Taylor (FC Taylor) and Advanced Lamel models (Alamel)) are performed to calculate the texture and average Taylor factor evolution with the increment of shear strain, on the basis of the measured rolling textures. After the simulations, the shear strain at which texture softening happens is recorded for each alloy and each shear angle. For alloys AA3004 and AA5182, it is found the texture-softening trend is similar to the experimental observations, which showed that the strain localization starts at smaller strains at shear angles of around 30-60o and 120-150o, finally leading to early failure. On the contrary, for alloy AA1200, the calculated average Taylor factor evolution does not resemble the flow behaviour. Furthermore the conclusions for alloys AA3004 and AA5182 are only qualitative, as the value of texture-softening strains predicted by simulation seems different from the observations. This shows that the importance of other effects such as possible microstructural softening mechanisms, especially the one due to the change of strain path (rolling/shear). Then for future models, it will be necessary to incorporate both the texture effects and microstructural effects comprehensively in order to precisely predict the strain localization behaviour of materials.