bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microstructural Behavior of Poly-Si Implanted with Oxygen
Authors: David Theodore N. , Huang WenLing M. , Crozier Peter A. 
Published: March 2011

ABSTRACTPoly-Si layers are used for various applications in integrated-circuit manufacturing technology. In most cases, the microstructure of the layers can have a significant impact on performance of the structures. In the present study, poly-Si layers implanted with 1E14 and 1E16 oxygen cm-2 were characterized using transmission electron-microscopy (TEM). Layers implanted with 1E16 cm-2 oxygen had exhibited lower variations in sheet-resistance for a given variation in post-implant anneal temperature. The microstructural behavior of the films was therefore of interest. TEM characterization showed differences in the microstructure of poly-Si implanted with 1E14 and 1E16 oxygen cm-2. Layers implanted with 1E14 doses showed a columnar grain-structure similar to as-deposited poly-Si layers. Grain-sizes were quite uniform and relatively small. Layers implanted with 1E16 doses showed a strongly defected grain-structure quite different from as-deposited poly-Si layers. The columnar structure had been largely destroyed. Grain-sizes were less uniform, with primarily large grains but also small grains being present. There are indications that the 1E16 samples had been amorphized by the implant and recrystallized by the anneal, but it is not clear from these samples whether this is the cause for the variation in resistance-behavior (between IE 14 and IE 16 samples). TEM micrographs are indicative of the presence of oxygen-bubbles in both sets of implanted specimens. The bubbles arise due to the oxygen implant. There is no noticeable correlation between poly-Si grain-boundaries and the bubbles.
The Structure and Properties of Grain Boundaries in Ni3Al
Authors: Mills M. J. , Goods S. H. , Foiles S. M. 
Published: March 2011

ABSTRACTThe mechanical behavior of polycrystalline intermetallic compounds are often strongly influenced by the properties of the interfaces present. A classic example of this is the intergranular fracture exhibited by polycrystalline Ni3Al, and the dramatic increase in ductility upon the addition of small amounts of boron. It has been proposed that boron may promote the transmission of slip across grain boundaries by inducing the formation of a local region of compositional disorder. The results of experimental efforts to characterize the effect of boron on the structure and chemistry of these grain boundaries are summarized. Recent high resolution transmission electron microscopy studies using oriented bicrystals are described which indicate that there is no apparent change in the compositional ordering to within 0.5 nm from the boundary. These experimental results are compared with the results of atomistic calculations which have been used to examine the effect of stoichiometry and boron content on the energy and degree of ordering of these boundaries. The proposed mechanisms of intergranular fracture in Ni3Al are discussed based on this experimental and theoretical work.
Phase Transitions at Internal Interfaces
Authors: Rottman Craig 
Published: March 2011

ABSTRACTInterfaces often undergo phase transitions even though nothing special is happening to the bulk solid. These transitions are possible in any internal interface, such as a grain boundary, an interphase boundary, a stacking fault, or an antiphase boundary. As for bulk solids, interface transitions may be defined from a thermodynamic point of view. When distinct interfacial phases coexist, interfacial phase diagrams are useful in visualizing thermodynamic data. Various classes of these transitions will be discussed in general and then illustrated with examples from recent work on models and experimental systems.
Atomic Structure of the SnO2(110) Surface
Authors: Godin T. J. , Lafemina John P. 
Published: March 2011

ABSTRACTUsing a tight-binding, total-energy model, we examine atomic relaxations of the ideal stoichiometric and reduced tin oxide (110) surfaces. In both cases we find a nearly bond-length conserving rumple of the top layer, and a smaller counter-relaxation of the second layer. These calculations show no evidence of surface states in the band gap for either surface.
Grain-Boundary-Mediated Failure in Polycrystals
Authors: Nichols C. S. , Smith D. A. 
Published: March 2011

ABSTRACTIt is well known that the atomic structure of an interface has some influence on its properties and thus on the properties of a poly crystalline ensemble as a whole. However, with the enormously large number of interface structures possible and no cohesive framework within which to understand them, it seems a hopeless task to search for structure-property relationships for all interfaces. Rather, we have adopted the viewpoint that interfaces may be grossly categorized into low-misorientation angle/special boundaries and random boundaries with a subsequent two-state division in their properties. We will discuss a simple methodology for examining stress-voiding and electromigration failures in thin metallic interconnects that takes the differing abilities of the interface classes to contribute to failure into account. We thus provide one of the first attempts to account consistently for the atomic structure of an interface and the macroscopic behavior observed in a poly crystalline system.
Hydrogen Segregation To Interfaces
Authors: Marwick A. D. , Liu Joyce C. , Krakow W. , Thompson R. D. 
Published: March 2011

ABSTRACTIn order to achieve a better understanding of hydrogen segregation to interfaces, a combination of techniques is being used in which hydrogen is deliberately introduced into planar interfaces between thin films, then the segregation measured using highenergy ion-beam profiling techniques. Results are given for heterophase interfaces produced by epitaxial deposition on silicon: The AI/Si (111) and CoSi2/Si (001) interfaces. A preliminary study of Au tilt boundaries in thin-film bicrystals shows the presence of a large amount of hydrogen, ∼1016 atoms/cm2, in the boundary after plasma hydrogenation, but also the presence of C impurity (∼ 1.6 × 1015 atoms/cm2 ) and Ag. We conclude that some of the hydrogen in the boundary may have been chemically bound to the carbon.
An Atom Probe Field Ion Microscope Investigation Of The Role Of Boron In Precipitates And At Grain Boundaries In NiAl
Authors: Jayaram Raman , Miller M. K. 
Published: March 2011

ABSTRACTThe high resolution analytical technique of Atom Probe Field Ion Microscopy (APFTM) haseen used to characterize grain boundaries and the matrix of a stoichiometric NiAl alloy doped with 0.04 (100 wppm) and 0.12 at. % (300 wppm) boron. Field ion images revealed boron segregation to the grain boundaries. Atom probe elemental analysis of the grain boundaries measured a boron coverage of up to 30% of a monolayer. Extensive atom probe analyses also revealed a fine dispersion of nanoscale boride precipitates in the matrix. The boron segregation to the grain boundaries was found to correlate with the observed suppression of intergranular fracture. However, the decrease in ductility of boron-doped NiAl is attributed in part to the precipitation hardening effect of the boride phases.
Environment Sensitive Embedding Energies of Impurities, and Grain Boundary Relaxation in Iron
Authors: Krasko Genrich L. 
Published: March 2011

ABSTRACTImpurities, such as H, P, S, B, etc, have a very low solubility in iron, and therefore prefer to segregate at the grain boundaries (GBs). In order to analyze the energetics of the impurities on the iron GB, the LMTO calculations were performed on a simple 8-atom supercel 1 emulating a typical (capped trigonal prism) GB environment. The so-called “environment-sensitive embedding energies” were calculated for H, B, C, N, O, Al, Si, P, and S, as a function of the electron charge density due to the host atoms at the impurity site. It was shown that, at the electron charge density typical of a GB, B and C have the lowest energy among the analyzed impurities, and thus would compete with them for the site on the GB, tending to push the other impurities off the GB. The above energies were then used in a modified Finnis-Sinclair embedded atom approach for calculating the equilibrium interplanar distances in the vicinity of a (111) σ3 tilt GB plane, both for the clean GB and that with an impurity. These distances were found to be oscillating, returning to the equilibrium spacing between (111) planes in bulk BCC iron by the 10th-12th plane off the GB plane. H, B, C, N and O actually dampen the deformation wave (making the oscillation amplitudes less than in the clean GB), while, Al, Si, P and S result in an increase of the oscillations. The effect of B, C, N and O may be interpreted as cohesion enhancement; this conclusion supports our earlier first-principles results [1] on B and C.
Xafs Studies of Cr-Si-O Interfaces with Al and Polyimide by using Synchrotron Radiation
Authors: Ogata Kiyoshi , Nakano Asao , Narizuka Yasunori , Watanabe Takayoshi , Yamazaki Tetsuya 
Published: March 2011

ABSTRACTThe structure change of a Cr-Si-O thin film with regard to heat-treatment was investigated not only by the transmission XAFS method but by the surface sensitive XAFS method using synchrotron radiation. As a result of transmission XAFS, the Cr-Si-O thin film as sputtered has an amorphous structure like a mixture of SiO2, Cr and CrSix. After heat-treatment to 650 K, Si-Cr bonds decreased and Si-O and Cr-Cr bonds increased. CrSix is unstable in the system. The interfacial studies by the surface XAFS method showed i) at the interface with polyimide, there is a thin layer which is dominantly made of Cr2O3 and ii) at the interface with Al, Cr atoms are mainly coordinated to Cr. Analyses by the XAFS method gave consistent results with chemical analyses by x-ray photoelectron spei roscopy and observation by transmission electron microscopy.
Using Ultrathin-Film, Modulated Composites to Control the Reaction Mechanism of Ternary Compound Formation
Authors: Fister Loreli , Johnson David C. 
Published: March 2011

ABSTRACTA predictable, controllable approach to the synthesis of ternary compounds through known intermediates is presented. Thin and ultrathin film superlattices were made in the Mo-Se, Cu-Se and Mo-Cu systems. Differential scanning calorimetry, low- and high-angle x-ray diffraction were used to assess the interdiffusion and nucleation reactions between elemental layers in these one-dimensional crystals. The experimental parameter modulation distance was used to influence the interfacial reactions. The results from each binary system were then used to predict the reaction pathway in the synthesis of a ternary compound, Cu2Mo6Se8. Superlattices with two different lengthscales were investigated. In the first, only one intermediate, MoSe2 which typically crystallizes at ∼200'C, is observed prior to the crystallization of Cu2Mo6Se8. In the second, no crystalline intermediates are observed below 6000 C.
Formation And Stability Of Nanocrystalline Nb-Cu Alloys
Authors: Abe Yoshio R. , Holzer J. C. , Johnson W. L. 
Published: March 2011

ABSTRACTNanocrystalline Nb100−xCux (0 ≤ x ≤ 30) alloys of 8 – 25 nm grain size are synthesized with the mechanical alloying technique. Differential scanning calorimetry reveals two separate stages of grain growth. In the first stage, the grain growth is associated with migration of solute Cu atoms to grain boundaries. Grain growth stops as the grain boundaries are saturated with Cu. The second reaction takes place either when the threshold for the nucleation of an Fcc Cu phase in the grain boundary is overcome by thermal activation, or when segregating Cu atoms in the grain boundary are driven by diffusion to the growing Cu grains, and the Cu concentration in the grain boundary drops. This increases the grain boundary energy, and initiates a second stage of rapid grain growth.
Interface Electronic And Magnetic Structures Of Layered Fe In Contact With MgO
Authors: Kim Young Keun , McHenry Michael E. , Oliveria Manuel P. , Eberhart Mark E. 
Published: March 2011

ABSTRACTA model based on the state-of-the-art, first-principles layer Korringa-Kohn-Rostoker (LKKR) method has proven to be very effective in describing the electronic and magnetic structure of metal/ceramic interfaces. We have performed self-consistent field computations incorporating spin polarization both for Fe/MgO superlattice (bulk technique) and for MgO/Fe/MgO sandwich (layer technique) systems. Muffin-tin potentials were employed for both materials in our computations. Iron layer was embedded in MgO, the host material, to have a [110](100)Fe / [100](100)MgO contact configuration. A large enhancement of magnetic moments has been found at the interface.
Hrem Study On The Interfacial Structure In Oxygen-Defective CaMnO3−x System
Authors: Shibahara H. , Taguch H. 
Published: March 2011

ABSTRACTElectron diffraction and high resolution electron microscope observation for CaMnO3−x (x=0. 02 and 0. 05) showed unique features of the ordered structure. A coherent intergrowth of several phases with a long period in CaMnO3−x composed of extended perovekite units was observed. The relation in crystallography in the family of ordered perovskite related oxides in CaMnO3−x, which could help towards an understanding of magnetic properties and catalytic action of CaMnO3−x, is discussed.
High Resolution Electron Microscopy Studies On The Microstructure Of β-Si3N4w/Al Interfaces In A β-Si3N4w/6061Al Composite
Authors: Ning X. G. , Pan J. , Hu K. Y. , Ye H. Q. 
Published: March 2011

ABSTRACTThe whisker/matrix interfaces in a β-Si3N4w/60 61Al composite were structurally characterized by high resolution transmission electron microscopy (HRTEM). It was shown that there was a nearly amorphous layer (2–3 nm thickness) at a whisker/matrix interface. The magnesium segregation at the whisker/Al interface was revealed by electron dispersive analysis of x-ray (EDAX). MgO and MgAl2O4 nanocrystal particles were formed at the whisker/matrix interface due to the Mg segregation there during the manufacturing of the composite. The Mg2Si particles preferred to precipitate at the whisker/Al interface when the composite was processed with T6 heating treatment. There were specific orientation relationship of the MgAl2O4 or Mg2Si particles with the β-Si3N4 whiskers.
Study Of Interfaces In XDTM Al/TiCp Metal Matrix Composites
Authors: Mitra R. , Chiou W. A. , Weertman J. R. , Fine M. E. , Aikin R. M. 
Published: March 2011

ABSTRACTThe metal-ceramic interface in an XDTM Al/TiCp metal matrix composite has been characterized in as-extruded, recrystallized, and high temperature heat-treated conditions. In both the as-extruded and recrystallized composite, the interface is atomically abrupt. Localized orientation relationships exist between Al and Tic that lead to some degree of coherency at the interface. Recrystallization produces semicoherent interfaces by formation of subgrains in the Al adjacent to the Tie particles. Few interfaces show cracking, even after extensive deformation. Lack of cracking together with the direct contact down to atomic level, observed between the two phases are evidence for excellent bonding between the carbide particles and the aluminum matrix. Heat treating samples at 913 k for 24 hours produces reaction products like Al3Ti and Al4C3. These reactions are explained on the basis of thermodynamic data.
Interface And Near-Interface Microstructure Of Discontinuous Reinforced Metal Matrix Composites
Authors: Lucas James P. , Yang Nancy Y. C. , Stephens John J. 
Published: March 2011

ABSTRACTInterfacial microstructure can have a significant influence on the microfracture processes of discontinuous reinforced metal matrix composites (DMMCs). The fracture properties, however, are largely influenced by the microfracture and deformation mechanisms associated with the matrix microstructure and with the interface microstructure. Also, it is known that the paniculate morphology and distribution can modify the deformation process by influencing the stress state that develops in the matrix materials near the reinforcement. Along with the matrix microstructure, characterizing the role of the interfacial and the near-interfacial microstructure is essential for a broader understanding of fracture behavior in DMMCs. To characterize the microstructure of cast DMMCs, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and electron microprobe (EMP) examinations were conducted at the interface and in regions near the particulate/matrix interface. Materials studied consisted of cast Al-4.5Cu and Al-7Si matrix alloy systems with B4C and SiC reinforcement. In general, the interfacial and matrix microstructure of Al-4.5Cu/SiC and Al-4.5 CuB4C composites exhibited little variance, i.e. the reinforcement type had no apparent effect on the resultant microstructures. For the Al-7Si system, however, significant microstructural variance was observed both in the matrix and interfacial regions. In the Al-7Si/B4C composite, an extensive reaction zone was found at the B4C interface. Interfacial compounds observed in Al-7SiC/B4C were Ti(O,B), Si, and MgB6 precipitates. In the near-interface region compounds such as Alx(B, C, 0)y, AlxMg(1−x)B2, and Al4C3 were found. In sharp contrast to Al-7SiC/B4C, an extensive interfacial reaction zone was not revealed for Al-7Si/SiC MMC. Only isolated, extremely fine second phase precipitates were observed on SiC paniculate interfaces. Fracture surface evidence suggested that both the matrix and the interface microstructure influenced deformation and microfracture mechanisms in DMMCs.
Lomer Dislocations in (0 0 1) GaSb/GaAs Heterostructure.
Authors: Rocherj André M. , Kang Joon M. , Ponchet Anne 
Published: March 2011

ABSTRACTThe (001) GaSb/GaAs heterostructure reveals a nearly complete relaxation of the misfit strain. This relaxation is connected to the highly regular network of Lomer dislocations which is a consequence of island growth conditions.
Stress and Microstructure in Lpcvd Polycrystalline Silicon Films: Experimental Results and Closed Form Modeling of Stresses
Authors: Krulevitch P. , Johnson G. C. , Howe R. T. 
Published: March 2011

ABSTRACTCharacterization of undoped polycrystalline silicon films indicates that correlations exist between stress and microstructure. Films of thickness between 0.5–3.6 μm were deposited onto SiO2-covered single crystal silicon wafers between 605 and 700°C using low pressure chemical vapor deposition (LPCVD). The average in-plane film stress and the stress gradient through the film thickness were determined from wafer curvature measurements, and film microstructure was studied with cross-sectional TEM. Films deposited near 605°C exhibit overall tensile stresses that result from an amorphous to crystalline phase change. At deposition temperatures exceeding 630°C, a columnar grain structure evolves out of a transition region of small grains at the SiO2 interface. The columnar films are compressive, with the source of compression linked to the region of small grains. Stress is modeled using a closed form solution ihat considers a linearly elastic contracting ellipsoidal inclusion near the surface of a half space. Several applications of the stress model are discussed.
Stresses in UHV Planar Magnetron Sputtered Films
Authors: Hudson C , Somekh R. E. 
Published: March 2011

ABSTRACTA method has been developed to measure the stress in films which have been sputtered using a planar magnetron in a small-scale UHV chamber. The stress has been measured for diffent materials as a function of the sputtering gas pressure P and the substrate-target distance d. It is found that the stress in films of the same material deposited at different values of d is dependent only on the pressure-distance product (Pd), except at short (less than about 30mm) distances. The value of Pd required to produce a stress-free film is found to increase with the more extreme ratios between the atomic masses of the film material and the sputtering gas for the case of metals. However, the required Pd product is higher for the case of amorphous semiconductors. The stress in alloy films is also investigated.
Finite Element Analysis of the Mechanical Performance of Benzocyclobutene Structures in Multichip Modules.
Authors: Shaffer E. O. , Townsend P. H. , Radler M. J. , Carriere C. J. 
Published: March 2011

ABSTRACTPolymeric materials are used as interlayer dielectrics for multichip modules. One of the central challenges for these structures is management of the large stresses induced by the differences in the thermal properties of the inorganic component structures and the organic film during processing.Finite clement analysis has been used to model the stresses in the dielectric material in practical structures used in multilayer microelectronic architecture, such as interlayer vias and the associated internal metal patterns. Calculations have been performed on the stress field at the corner of square vias in benzocyclobutcne based interlayer dielectrics and related polymeric materials. The effects of the thermal and mechanical properties of the polymeric coating on the stress fields in metal patterns have been calculated and provide insight for design and process optimization.
Measurement of Residual Stress-Induced Bending Moment of P+ Silicon Films
Authors: Chu W. H. , Mehregany M. , Ning X. , Pirouz P. 
Published: March 2011

AbstractThis paper presents results from measurements of residual stress-induced bending moment of heavily-boron-doped (p+) silicon films. Microfabricated free-standing cantilever beams of p+ silicon were fabricated by using anisotropie etching of (100) silicon wafers in ethylene-diamine and pyrocatechol. The p+ etch stops forming the cantilevers were created by diffusion from a solid source at 1125°C for one and two hour time durations. The nonuniform residual stress distribution through the thickness of the p+ silicon cantilevers resulted in a deflection of the beams. The as-diffused p+ silicon films had a residual stress distribution through the film thickness which resulted in negative bending moments. Thermal oxidation subsequent to the diffusion step modified the residual stresses near the top surface or, perhaps, plastically deformed the near surface region of the p+ thin film. As a result, thermally oxidized p+ silicon films exhibited a positive bending moment. Measurements of the deflection curves of the beams in conjunction with beam theory were used to calculate the residual stress-induced bending moments.
Characterization of Stress and Texture in Rtcvd Poly-Si Layers by X-Ray Diffraction
Authors: Bársony István , Klappe Jos G.E. , Ryan Tom W. 
Published: March 2011

ABSTRACTThe properties of polycrystalline silicon layers deposited by RTCVD have been studied by texture, stress and electrical analyse. The intrinsic layers intended for applications in integrated IC processing are very much textured with the preferred orientation depending on deposition temperature and atmosphere. Very low residual film stress in the order of 10 dyn/cm2 was detected, and a transition from compressive to tensile stress with increasing deposition temperature around 800°C was observed. This was associated with the development of the columnar structure by the (110) orientation becoming dominant at the expense of the (100) texture. Also the effect of post-deposition anneal ambience on the grain structure has been studied. Grain size and grain-boundary trapping in after doped layers have been evaluated in P-implanted RTA activated layers.