bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Temperature Synthesis of MO2C/W2C Superlattices via Ultra-Thin Modulated Reactants
Authors: Johnson Christopher D. , Johnson David C. 
Published: April 2011

AbstractWe report here a synthesis method of preparing carbide superlattices using ultra-thin modulated reactants. Initial investigations into the synthesis of the binary systems, Mo2C and W2C using ultra-thin modulated reactants revealed that both can be formed at relatively low temperature(500 and 600°C respectively). DSC and XRD data suggested a two step reaction pathway involving interdiffusion of the initial modulated reactant followed by crystallization of the final product, if the modulation length is on the order of 10 Å. This information was used to form Mo2C/W2C superlattices using the structure of the ultra-thin modulated reactant to control the final superlattice period. Relatively large superlattice modulations were kinetically trapped by having several repeat units of each binary within the total repeat of the initial reactant. DSC and XRD data again are consistent with a two step reaction pathway leading to the formation of carbide superlattices.
Pressureless Co-Sintering of Al2O/ZrO2 Multilayers and Bilayers
Authors: Cai Peter Z. , Green David J. , Messing Gary L. 
Published: April 2011

AbstractVarious types of damage were observed in pressureless-sintered Al2O3/ZrO2 symmetric laminates (multilayers) and asymmetric laminates (bilayers) fabricated by tape casting and lamination. These defects included channel defects in ZrO2-containing layers, Al2O3 surface defects parallel to the layers, decohesion between the layers, and transverse damage within the Al2O3 layer in the bilayers. Detailed microscopic observation attributed the defects to a combined effect of mismatch in both sintering rate and thermal expansion coefficient between the layers. Crack-like defects were formed in the early stages of densification, and these defects acted as pre-existing flaws for thermal expansion mismatch cracks. Curling of the bilayers during sintering was monitored and the measured rate of curvature change, along with the layer viscosities obtained by cyclic loading dilatometry, was used to estimate the sintering mismatch stresses. The extent of damage could be reduced or even eliminated by decreasing the difference in layer sintering rate. This was accomplished by reducing the heating rates or by adding Al2O3 in the ZrO2 layers.
Influence of Cu Deposition Conditions on The Microstructure and Adhesion of Cu/Cr Thin Film To Polyimide Film
Authors: Joh Cheol-Ho , Kim Young-Ho 
Published: April 2011

AbstractsThe microstructure of Cu thin films in various deposition conditions and the influence of their microstructure on the adhesion strength between Cu/Cr films and polyimides were studied. Cr films (50 nm thick) and Cu films (500 or 1000 nm thick) were deposited on polyimide films by DC magnetron sputtering. The Ar pressure during Cu deposition was controlled to 5, 50, and 100 mtorr. The microstructure was characterized using SEM and TEM. The adhesion strength between Cu/Cr and polyimide was measured using a modified Tpeel test. Plastic deformation of the peeled metal was qualitatively measured using the XRD technique. The Cu film sputtered at 5 mtorr has a dense and uniform structure, while lowdensity regions or open boundaries between columns exist in the film deposited at higher pressure. As sputtering pressure increases, open boundaries are observed more frequently. The peel adhesion strength of Cr film to polyimide increases with Cu sputtering pressure. The adhesion change of Cu/Cr film can be interpreted as the difference in plastic deformation. Open boundaries in the Cu film seem to play an important role in increasing the amount of plastic deformation in the metal film during peeling.
In Situ Electron Spectroscopic Identification of Carbon Species Deposited by Laser Ablation
Authors: Samano E. C. , Soto Gerardo , Gamietea Arturo , Cota Leonel 
Published: April 2011

AbstractThin carbon films were grown on Si (111) substrates by ablating a graphite target utilizing an excimer pulsed laser in a UHV Riber © LDM-32 system. Two kinds of films were produced, a highly oriented pyrolytic graphite (HOPG) type and a diamond-like carbon (DLC) type. A relationship of the films microstructure with laser power density and substrate conditions was observed. The HOPG films were homogeneous but the DLC films were heterogeneous, as shown by micrographs. The thin films are monitored and analyzed in situ during the first stages of the deposition process. The monitoring was done by RHEED and the characterization by several surface spectroscopic techniques, AES, XPS and EELS. The formation of a SiC interface was observed for both films due to the reaction of the first carbon species with the substrate surface.
Detection of Similar Elastic Properties Using a Magnetic Force Controlled Afm
Authors: Yamamoto Shin-Ichi , Yamada Hirofumi , Jarvis Suzanne P. , Motomatsu Makoto , Tokumoto Hiroshi 
Published: April 2011

AbstractWe have investigated regional variations of elastic properties using a magnetic force controlled AFM. A piece of small magnet was fixed at the end of the backside of the AFM cantilever so as to apply forces directly to the tip through the external magnetic field of an electromagnet. By modulating the applied forces to the tip and measuring the resulting amplitude of oscillation, a sensitive measurement of the local contact stiffness can be made. We have applied this technique to phase-separated films of polystyrene/polymethylmethacrylate (PS-PMMA) which have almost identical Young's moduli.
Finite Element Modeling of Grain Aspect Ratio and Strain Energy Density in a Textured Copper Thin Film
Authors: Vinci R. P. , Bravman J. C. 
Published: April 2011

AbstractWe have modeled the effects of grain aspect ratio on strain energy density in (100)-oriented grains in a (111)-textured Cu film on a Si substrate. Minimization of surface energy, interface energy, and strain energy density (SED) drives preferential growth of grains of certain crystallographic orientations in thin films. Under conditions in which the SED driving force exceeds the surface- and interface-energy driving forces, Cu films develop abnormally large (100) oriented grains during annealing. In the elastic regime the SED differences between the (100) grains and the film average arise from elastic anisotropy. Previous analyses indicate that several factors (e.g. elimination of grain boundaries during grain growth) may alter the magnitude of the SED driving force. We demonstrate, using finite element modeling of a single columnar (100) grain in a (111) film, that changes in grain aspect ratio can significantly affect the SED driving force. A minimum SED driving force is found for (100) Cu grains with diameters on the order of the film thickness. In the absence of other stagnation mechanisms, such behavior could cause small grains to grow abnormally and then stagnate while large grains continue to grow. This would lead to a bimodal grain size distribution in the (100) grains preferred by the SED minimization.
Mechanical Properties of CuNi Films
Authors: Brückner W. , Macionczyk F. , Reiss G. 
Published: April 2011

AbstractThe mechanical properties of resistive CuNi films sputtered on both silicon wafers and flexible Kapton foils are important for reliability and lifetime of resistors. Studies of stress-temperature dependence and stress relaxation, stress-strain measurements and scanning scratch tests were performed to investigate film stresses, elastic properties, plastic flow, stress for crack initiation and film adhesion. The growth and annealing stresses were found to be tensile and can be seen as the reason for resistance degradation by stress relaxation due to plastic flow. The strains for crack initiation of 0.2 % to 0.7 % depending on film thickness and annealing restrict the application in resistors on flexible substrates. The film adhesion can be improved by a NiCr base-layer.
Indentation Modulus and Hardness in Heteroepitaxial AlxGa1-xP Films
Authors: Roos B. , Santana C. J. , Abernathy C. R. , Jones K. S. 
Published: April 2011

AbstractAlxGa1-xP layers (0 ≤ x ≤ 0.7), with thicknesses of ≤ 1 μm were grown on Si (100) wafers by metal-organic molecular beam epitaxy (MOMBE) at 450 °C. Transmission electron micrographs of the single crystal films revealed that the microstructure contains stacking faults and microtwins especially near the interface as well as both threading and misfit dislocations. Hardness and elastic modulus were measured using a Nanotest 500 indenter, which can probe the film properties without influence from the substrate.The hardness H varies linearly according to (11.8 - 2.3x) GPa. The absence of alloy hardening is due to the fact that there is no difference in atomic size of Al and Ga. The indentation modulus E/(1-v 2) decreases monotonically from 136 GPa for GaP to 129 GPa for Al0.7Ga0.3P and bows only slightly (about 2 %) below the straight line of linear interpolation.
Origins of Residual Stress in Mo and Ta Films: the Role of Impurities, Microstructural Evolution, and Phase Transformations
Authors: Parfitt L. J. , Karpenko O. P. , Rek Z. U. , Yalisove S. M. , Bilello J. C. 
Published: April 2011

AbstractBoth the sign and magnitude of residual stress can vary with the thickness of sputter deposited films. The origins of this behavior are not well understood. In this work, we consider the correlation between the residual stress behavior and the depth dependence of impurities in thin (2.5 nm - 150 nm) sputtered Mo and Ta films. We also consider the effects of phase transformations and microstructural changes on the stress behavior. Films were deposited onto Si substrates with native oxide. The residual stress observed in the Mo films varied from highly compressive at 2.5 nm film thickness to ∼ 0 ˜ 10 nm thickness. Ta films also exhibited a high compressive stress, which relaxed from highly compressive to tensile between 10 nm and 50 nm film thickness. Impurities in the films may originate from the sputtering targets, the background gases, and the substrate surfaces. Auger Electron Spectroscopy (AES) results showed the presence of O and C contamination near the film/Si interface; these impurities contributed to the compressive stresses in the thinner films. As anticipated, both Mo and Ta films exhibited grain growth as a function of film thickness, which may have contributed to the relaxation in the compressive stress. The Mo films were entirely bcc. The Ta films showed a transformation from the amorphous phase to the β crystalline phase between 2.5 nm and 20 nm film thickness, which contributed to the relaxation in stress observed in that thickness regime.
Fracture of Thin Tantalum Nitride Films on Ain Substrates
Authors: Moody N. R. , Medlin D. , Norwood D. P. 
Published: April 2011

AbstractNanoindentation, continuous nanoscratch testing, and transmission electron microscopy were used in this study to determine the structure-property relationships of thin tantalum nitride resistor films on aluminum nitride substrates. The films were sputter-deposited to a nominal thickness of 200 nm during one production run and then tested at room temperature. Most films were uniform in structure and thickness, consisting of fine equiaxed crystallites along the film-substrate interfaces and long columnar grains further away from the interface. However, one film varied greatly in thickness across the substrate. It had large crystallites along the film-substrate interface and clusters of columnar grains. Most importantly, it contained a far greater amount of porosity than the other films. The high porosity content led to significantly lower elastic moduli and hardness values than the low porosity films and a much greater susceptibility to fracture.
Ordered Structure in Lead Magnoniobate (PMN) by Resonant X-Ray Scattering
Authors: Gosula V. , Chen Haydn , Teslic S. , Egami T. , Vakhrushev S. 
Published: April 2011

AbstractHalf integer superlattice reflections characteristic of ordered structure in PMN (Pb(Mg1,3Nb2,3)O3) single crystal have been measured using resonant synchrotron x-ray scattering near the Pb LIII absorption edge. These superlattice peaks have been previously reported in PMN by electron diffraction, and were interpreted in the context of a two phase Nb/Mg ordering model to explain its relaxor ferroelectric behavior. Nevertheless, the microscopic origin of the superlattice peaks is controversial. Previous results have shown that the Nb atom contributes heavily to the superlattice peaks. However, the effective scattering factor for these peaks is significantly smaller than in the case of complete ordering. In addition, there is strong evidence that lead participates in the ordering.
X-Ray Absorption Fine Structure Applied to the Study of Systems with Lattice Instabilities
Authors: Leon J. MUSTRE DE , Conradson S. D. , Tyson T. , Bishop A. R. , Salkola M. , Espinosa F.J. , Peña J. L. 
Published: April 2011

AbstractWe present a simplified model of electrons and phonons in a three-site cluster as a paradigm of a system exhibiting a lattice instability. We point out the utility of X-ray absorption fine structure (XAFS) in the study of materials where the coupling between electrons and phonons leads to the appearance of such lattice instabilities. As examples of these systems, we present X-ray absorption fine structure (XAFS) measurements on magnetic manganese oxide materials and II-VI semiconductors. Both of these systems exhibit local lattice instabilities which are reflected in the transport properties. In the case of the manganese oxide La0.67Ca0.33MnO3 we observe a change in the Mn-O local structure accompanying the ferromagnetic and metal-insulator transitions. For In doped CdTe we observe the appearance of a lattice distortion centered at the Cd atoms as the In concentration is increased. This distortion is associated with the trapping of free charge carriers, leading to the saturation of the conductivity as the In concentration increases.
Microbeam XAFS Investigations on Fluid Inclusions
Authors: Mayanovic Robert A. , Anderson Alan J. , Bajt Saša 
Published: April 2011

AbstractIn this paper, we discuss the use of x-ray absorption fine structure (XAFS) techniques for the determination of structure of metal complexes in fluid inclusions heated to elevated temperatures. Analysis of Zn K-edge XAFS spectra measured from a single hypersaline fluid inclusion in quartz shows that the ZnCl42- complex is dominant at all temperatures up to and including 430 °C. The Zn-Cl bond length was found to decrease uniformly with temperature, up to nearly 2% at 430 °C in comparison to the value at 25 °C. The Zn-Cl mean-square relative displacement increased linearly with temperature, from a value of 0.0043 Å2 at 25 °C to 0.0089 Å2 at 430 °C.
X-Ray Absorption at Si K-Edge for Novel Compounds in the Ternary System Si-C-N
Authors: Kroll P. , Greiner A. , Riedel R. , Bender S. , Franke R. , Hormes J. , Pavlychev A. A. 
Published: April 2011

AbstractWe present results of Si K-edge XANES-investigations for novel Si-C-N containing solid phases prepared by annealing of Si(NCN)2 at temperatures between room temperature (RT) and 1600°C. The chemical equivalence of the NCN-group arid oxygen as a ligand of silicon is confirmed. The spectra show the presence of an intermediate crystalline phase and its decomposition. Furthermore the recrystallisation of a Si3N4/SiC composite material and its dependence on temperature can be seen.
Complete k-Space Visualization Of X-Ray Photoelectron Diffraction
Authors: Denlinger J. D. , Rotenberg Eli , Kevan S. D. , Tonner B. P. 
Published: April 2011

AbstractA highly detailed x-ray photoelectron diffraction data set has been acquired for crystalline Cu(001). The data set for bulk Cu 3p emission encompasses a large k-space volume (k=3–10 Å-1) with sufficient energy and angular sampling to monitor the continuous variation of diffraction intensities. The evolution of back-scattered intensity oscillations is visualized by energy and angular slices of this ‘volume’ data set. Large diffractyyion data sets such as this will provide rigorous experimental tests of real-space reconstruction algorithms and multiple-scattering simulations.
Application of Mxcd to Magnetic Thin-Film Sensors
Authors: Bedrossian P. J. , Tobin J. G. , Jankowski A. F. , Waddill G. D. , Anthony T. C. , Brug J. A. 
Published: April 2011

AbstractWhile Magnetic X-ray Circular Dichroism (MXCD) has been applied extensively to the extraction of elemental magnetic moments in various magnetic multilayers, the configuration of actual devices imposes certain constraints on the application of MXCD to devices. Using a set of real, thin-film spin valve devices with varying Cu spacer layer thicknesses, we demonstrate the correlation between MXCD and magnetoresistance measurements on those devices as well as the restrictions on the interpretation of MXCD data imposed by both the device topology and the formulation of realistic error estimates.
Generation and Suppression of Stacking Faults in Gap Layers Grown on Si(100) Substrates by Molecular Beam Epitaxy and Migration Enhanced Epitaxy
Authors: Takagi Y. , Yonezu H. , Samonji K. , Tsuji T. , Ohshima N. 
Published: April 2011

AbstractWe have investigated the generation process of crystalline defects in GaP layers grown on Si substrates (GaP/Si) by molecular beam epitaxy (MBE) and migration enhanced epitaxy (MEE). Transmission electron microscopy observations revealed that a regular network of misfit dislocations was generated in GaP/Si by MEE. On the other hand, threading dislocations as well as interfacial misfit dislocations were observed in GaP/Si by MBE. Moreover, stacking faults were generated in high density at the hetero-interface of GaP/Si by MBE. The density of stacking faults was drastically reduced by MEE.
Carrier Transport in Ordered and Disordered In0.53Ga0.47As
Authors: Ahrenkiel R. K. , Ahrenkiel S. P. , Arent D. J. , Olson J. M. , Wanlass M. 
Published: April 2011

AbstractGa0.47In0.53As films are grown by metal-organic chemical vapor deposition (MOCVD) on InP substrates and are lattice-matched to the latter. Studies have shown that by varying growth temperature and lattice orientation, some ordering of the metal sublattice is produced. In this work, we studied the excess carrier lifetimes in ordered and disordered films using an ultra-high frequency photoconductive decay measurement technique (UHFPCD). Excitation was provided by a Q-switched YAG laser (1.064 μs wavelength) with pulses of about 5 ns full width half maximum (FWHM). The transient photoconductive decay (PCD) signals varied markedly with the degree of ordering of the specific film. As description of the experimental results of these UHFPCD measurements follow.
MOCVD growth of ZnCdSe on InP (001) substrates
Authors: Won Hon-Kit , Hark S. K. 
Published: April 2011

AbstractA series of ZnCdSe epitaxial films containing various amounts of Cd were grown on InP (001) substrates using DEZn, DMCd and DESe in the temperature range of 350 to 450°C. The composition and structure of the films were studied by EDX and high resolution X-ray diffraction techniques. It was found that Cd rich films were obtained at low while Zn rich films at high growth temperatures. Double-crystal rocking curves of the films showed that the Cd rich films have substantially fewer defects than similar films grown on GaAs. This improvement in structure is attributed to the closer match of the lattice parameters of lnP and ZnCdSe. The independent determination of composition and structure allowed us to measure the degree of relaxation of the films. We found that even for films whose thickness far exceeds the critical thickness, complete relaxation is not achieved.
Preparation of pzt thin films on Pt/Ti/SiO2 and Pt/SiO2 Substrates by ECR Plasma Enhanced DC Magnetron Multi-target Reactive Sputtering
Authors: Kim Sung-Tae , Kim Hyun-Ho , Lee Moon-Yong , Lee Won-Jong 
Published: April 2011

AbstractPerovskite-phase lead zirconate titanate (PZT) thin films were fabricated at 4751C by the electron cyclotron resonance (ECR) plasma enhanced DC magnetron multi-target reactive sputtering method on Pt/Ti/SiO2/Si and Pt/SiO2/Si substrates. Stoichiometric perovskite PZT films were readily obtained on Pt/Ti/SiO2/Si substrates because Ti atoms which were out-diffused to the Pt surface facilitated Pb incorporation by forming lead titanate at the early stage of deposition process. Activation of oxygen by ECR plasma facilitated the oxidation reaction and Pb incorporation into the film. Thus perovskite-phase PZT can be obtained on the Pt/SiO2/Si substrate.
Diffusion Barrier Reliability with Respect to the Role of Tin Stoichiometry Between Al Metallization and Si Substrate
Authors: Tseng Han-Yu , Christou Aris , Young Dan , Tessner Ted , Orloff Jon 
Published: April 2011

AbstractIn this study, the relation between interdiffusion in Al/ TiN thin film couples and diffusion barrier stability has been investigated. The TiN diffusion barrier was deposited by reactive sputtering in an Ar-N2 gas mixture. The stoichiometry of TiN was achieved by varying the nitrogen-to-argon ratio in the sputtering gas. Interdiffiusion occurred after annealing for 30 minutes at 475°C and 575°C. Diffusion processes and interfacial reactions with respect to TiN stoichiometry were investigated via Auger Electron Spectroscopy (AES) depth profiling and X-ray diffraction (XRD). The barrier reliability with respect to the stoichiometry changes was established; nitrogen-deficient TiN films result in a high degree of interdiffiusion and decomposition at annealing temperatures of 475°C and 575°C. AI3Ti and AlN intermetallic compounds were formed at the interfaces. The sheet resistance of Al films was measured by four-point probe method. Resistance increases for all the annealed films were due to interdiffusion between Al and TiN. The degree of interdiffusion was analyzed by using AES and XRD.
(100) Oriented Platinum thin Films Deposited by Dc Magnetron Sputtering On SiO 2/Si Substrates
Authors: Park Dong-Yeon , Lee Dong-Su , Kim Min Hong , Park Tae-Soon , Woo Hyun-Jung , Yoon Euijoon , Chun Dong-ll , Ha Jowoong 
Published: April 2011

AbstractPlatinum(Pt) films were sputter-deposited on Si02/Si substrates under the mixed gas atmosphere of Ar and O2. Under certain deposition conditions, the films were oriented such that the (100) direction is normal to the substrate surface. The formation of the (100) texture was affected by the gas pressure and film thickness. After annealing at 650 °C for 1 hour, (100) oriented Pt films with the resistivity of pure Pt were obtained. The annealed Pt films all passed a tape adhesion test and had no defects such as hillocks or pinholes. The experimental results from this work are presented.