79 results on '"J. Bruley"'
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2. Double spin-torque magnetic tunnel junction devices for last-level cache applications
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G. Hu, C. Safranski, J. Z. Sun, P. Hashemi, S. L. Brown, J. Bruley, L. Buzi, C. P. D'Emic, E. Galligan, M. G. Gottwald, O. Gunawan, J. Lee, S. Karimeddiny, P. L. Trouilloud, and D. C. Worledge
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- 2022
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3. The teaching of TEM by telepresence microscopy over the internet
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E Voelkl, L F Allard, J Bruley, V J Keast, and D B Williams
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- 2022
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4. In-situ Plasma Conditioning of InGaAs / High-κ Interface Layers for Defect Density Control Compatible with Scalable FinFET Integration
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J. Rozen, Y. Ogawa, M. Hatanaka, T. Ando, E. Cartier, M.M. Frank, M. Hopstaken, J. Bruley, K.-T. Lee, J.-B. Yau, Y. Sun, R.L. Bruce, C. D'Emic, X. Sun, K. Suu, R.T. Mo, E. Leobandung, and V. Narayanan
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In situ ,Materials science ,business.industry ,Interface (computing) ,Scalability ,Optoelectronics ,Plasma ,business - Published
- 2018
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5. Dual-Lens Electron Holography for Junction Profiling and Strain Mapping of Semiconductor Devices
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A. Domenicucci, Yun-Yu Wang, and J. Bruley
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Electron mobility ,Materials science ,General Computer Science ,business.industry ,Holography ,Field of view ,Semiconductor device ,Electron holography ,law.invention ,Optics ,Semiconductor ,law ,Electron optics ,business ,Image resolution - Abstract
Electron microscopes have been used extensively to look at structure at the nanometer scale. Most of the information obtained from electron microscopes is amplitude information. Yet, the phase information of electron microscopy, which can be obtained from off-axis electron holography, provides unique information on electronic structure and structural changes in a wide variety of materials.For the semiconductor industry, junction profiling and strain mapping in Si at high spatial resolution provide information that is critical for further scaling of semiconductor devices. Because of the complex process conditions involved to control the junction position relative to the gate position, determination of junction position at high spatial resolution can help to reduce the cost and cycle time of development. Bright-field holography can measure the phase change of electrons traversing the materials, which is directly related to the mean inner potential of Si, indicating the junction position at the nanometer scale. Furthermore, in recent years stressors have been incorporated into devices to change the semiconductor lattice constant in the channel region and thereby enhance hole and electron mobility. Like the junction definition, the extra processing steps involved to add strain in a device have increased development and manufacturing costs. One way to minimize development cycle time is to monitor, at a nanometer scale, changes in channel deformation resulting from process changes. In 2008, Hytch et al. reported that dark-field holography can provide a promising path to nanometer scale strain mapping [1]. Cooper et al. reported using dark-field holography to measure strain related to different process conditions [2, 3].The requirements of electron holography to inspect the current generation of semiconductor devices are: (1) a fringe width (fringe overlap) in the range of about 100 to 800 nm for an adequate field of view (FOV), (2) fringe spacing between 0.5 and 10 nm for meaningful spatial resolution, (3) visibility of the fringe contrast (10–30%) for useful signal-to-noise ratio, and (4) adjust-ability of both the FOV and the fringe spacing relative to the sample. In previous papers and patent disclosures, we reported that we had developed a dual-lens electron holography method on a JEOL instrument to meet the above requirements, and later we implemented the same method on FEI instruments to provide a similar operational range for electron holography [4–6]. This dual-lens operation allows electron holography to be performed from low to high magnification and provides the FOV and fringe spacing necessary for two-dimensional (2D) junction profiling and strain measurements for devices with various sizes.In this article, we describe the electron optics for this method. We also describe several examples of junction profiling and strain mapping to show how to use dual-lens electron holography to resolve semiconductor device issues at high spatial resolution.
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- 2014
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6. Variable Magnification Electron Holography for 2-D Mapping of Semiconductor Devices
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A. Domenicucci, M. Kawasaki, Michael A. Gribelyuk, J. Bruley, John G. Gaudiello, and Yun-Yu Wang
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Variable (computer science) ,Optics ,Materials science ,General Computer Science ,business.industry ,Magnification ,Semiconductor device ,business ,Electron holography - Abstract
The exit electron wave from transmission electron microscopy (TEM) specimens contains both amplitude and phase information. In routine TEM imaging, only amplitude information is recorded on the recording devices (film or CCD camera) and phase information of the electron wave function normally is canceled out. In 1947, Dennis Gabor proposed off-axis electron holography, a method of interference imaging in which the phase and amplitude components of the electron beam are obtained to correct spherical aberration of the transmission electron microscope to improve spatial resolution. In that process, the electron beam is split into the two beams: the un-scattered electron beam (i.e. the reference wave) and the image beam (or object wave) diffracted by the specimen and exiting the bottom of the specimen surface.
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- 2004
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7. Aggressive SiGe Channel Gate Stack Scaling by Remote Oxygen Scavenging: Gate-First pFET Performance and Reliability
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M. M. Frank, E. A. Cartier, T. Ando, S. W. Bedell, J. Bruley, Y. Zhu, and V. Narayanan
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Electrical and Electronic Engineering ,Electronic, Optical and Magnetic Materials - Published
- 2012
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8. Electron energy-loss near-edge structure - a tool for the investigation of electronic structure on the nanometre scale
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David B. Williams, J. Bruley, Andrew J. Scott, Vicki J. Keast, and Rik Brydson
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Histology ,Chemistry ,Density of states ,Measure (physics) ,Nanometre ,Electron ,Electronic structure ,Atomic physics ,Spectroscopy ,Image resolution ,Engineering physics ,Spectral line ,Pathology and Forensic Medicine - Abstract
Electron energy-loss near-edge structure (ELNES) is a technique that can be used to measure the electronic structure (i.e. bonding) in materials with subnanometre spatial resolution. This review covers the theoretical principles behind the technique, the experimental procedures necessary to acquire good ELNES spectra, including potential artefacts, and gives examples relevant to materials science.
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- 2001
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9. The nitrogen aggregation sequence and the formation of voidites in diamond
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J. Bruley and I. Kiflawi
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Molecular nitrogen ,Annealing (metallurgy) ,Chemistry ,Mechanical Engineering ,Mineralogy ,Diamond ,chemistry.chemical_element ,General Chemistry ,engineering.material ,Crystallographic defect ,Nitrogen ,Natural diamonds ,Electronic, Optical and Magnetic Materials ,Crystallography ,Octahedron ,Materials Chemistry ,engineering ,Electrical and Electronic Engineering ,Chemical composition - Abstract
High-temperature annealing of type IaB diamonds containing platelets caused the conversion of the platelets to dislocation loops and the formation of octahedral shaped defects [T. Evans, I. Kiflawi, W. Luyten, G. Van Tendeloo, G.S. Woods, Proc. R. Soc. Lond. A 449 (1995) 295]. The chemical composition of these octahedral defects was investigated, and they were found to contain molecular nitrogen, thus showing them to be the same as the voidite defects observed in natural diamonds. This demonstrates the last stage of the sequence of the aggregation of nitrogen in diamonds. The amount of nitrogen in the ‘man-made’ voidites was found to be similar to the amount of nitrogen in the platelets before their conversion to dislocation loops. Also, a possible mechanism for the formation of B centres from A centres is discussed.
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- 2000
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10. An EELS study of segregation-induced grain-boundary embrittlement of copper
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J Bruley, Vicki J. Keast, and David B. Williams
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Materials science ,Polymers and Plastics ,Doping ,Metallurgy ,Metals and Alloys ,chemistry.chemical_element ,Intergranular corrosion ,Copper ,Spectral line ,Electronic, Optical and Magnetic Materials ,Brittleness ,chemistry ,Impurity ,Chemical physics ,Ceramics and Composites ,Grain boundary ,Embrittlement - Abstract
Grain-boundary segregation is a necessary, but not always sufficient, criterion for intergranular embrittlement of many metals and alloys. The reason why certain segregants induce embrittlement while others are harmless remains unclear, but it has been theorized that segregation may be responsible for local changes in the atomic bonding which, in turn, may produce brittle failure. Recent developments in electron energy-loss spectrometry in the analytical electron microscope permit correlation to be made between the presence of certain segregants and changes in the bonding of the atoms on the grain boundary. Because the effects in the energy-loss spectrum are small, the spatial-difference method (equivalent to a first-difference spectrum) is sometimes used to discern the spectral intensity changes. It is important to ensure that this method of processing the data does not induce the changes in the spectrum that are usually associated with changes in bonding, and this can be demonstrated by experimental comparison of energy-difference and spatial-difference spectra. Using direct measurement, as well as spatial-difference techniques, it is demonstrated that Bi and Sb, well-known embrittlers of Cu, induce consistent changes in the bonding of Cu, while Ag, a similar segregant which does not embrittle Cu, produces no detectable changes in the bonding.
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- 1999
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11. Measurement of the localized electronic structure associated with bismuth segregation to copper grain boundaries
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David B. Williams, Vicki J. Keast, and J Bruley
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Materials science ,Acoustics and Ultrasonics ,Electron energy loss spectroscopy ,Analytical chemistry ,chemistry.chemical_element ,Condensed Matter Physics ,Threshold energy ,Molecular physics ,XANES ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Bismuth ,Absorption edge ,chemistry ,Grain boundary ,Absorption (electromagnetic radiation) ,Spectroscopy - Abstract
Grain boundaries in copper doped with small amounts of bismuth have been examined by spatially resolved electron energy loss spectroscopy (EELS). The electron energy loss or x-ray absorption near edge structure (ELNES or XANES) yields information on the bonding state of the probed atoms. A white line was detected near the threshold energy of the bulk absorption edge when the electron probe is located within 1 nm of the grain boundaries. This spectroscopic feature provides direct evidence that the grain boundary influences the local electronic structure and may have implications on how Bi embrittles the grain boundaries in Cu. Effects are only observed in those boundaries where the presence of Bi was confirmed using energy dispersive x-ray EDX spectroscopy. Furthermore, no evidence was found to indicate, within detection sensitivity limits, any co-segregation of oxygen to these boundaries.
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- 1996
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12. Nitrogen determination and characterization in natural diamond platelets
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P. J. Fallon, L. M. Brown, J. Bruley, and J. C. Barry
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Physics and Astronomy (miscellaneous) ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,Diamond ,Crystal structure ,engineering.material ,Condensed Matter Physics ,Nitrogen ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry ,Transmission electron microscopy ,law ,engineering ,General Materials Science ,Electron microscope ,Spectroscopy ,High-resolution transmission electron microscopy ,Carbon - Abstract
The {100} platelets in natural type IaA/B diamonds have been examined by spatially resolved electron-energy-loss spectroscopy and high-resolution transmission electron microscopy (HRTEM). Nitrogen concentrations were determined for platelets of four different stones. The nitrogen concentration was observed to vary from diamond to diamond and to be less than required by previous nitrogen platelet models, but more than required by a pure carbon platelet model. A new model for the platelet, which agrees with the present and previous data, has been developed. Image simulations from the model are shown to correspond to HRTEM 〈110〉 images of the platelets.
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- 1995
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13. Modelling the bonding at metal-ceramic interfaces using PEELS in the STEM
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Rik Brydson, J. Bruley, Manfred Rühle, Christina Scheu, and H. Müllejans
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Valence (chemistry) ,Chemistry ,Spatially resolved ,Electron energy loss spectroscopy ,Analytical chemistry ,Metal ceramic ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Reaction interface ,Chemical bond ,Transmission electron microscopy ,Chemical physics ,Instrumentation ,Electron microscopic - Abstract
A strategy for the elucidation of bonding at metal-ceramic interfaces is presented. Specific reference is drawn to (scanning) transmission electron microscopic (STEM) studies on metal-alumina interfaces. The use of spatially resolved electron energy loss spectroscopy (EELS) in the determination of local coordinations and valence states at interfaces is discussed. When such results are combined with EELS or energy dispersive X-ray (EDX) compositional linescans, high-resolution imaging and surface analytical techniques, important information may be derived about chemical bonding mechanisms which may ultimately determine property-processing relationships.
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- 1995
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14. Spatially resolved electron energy-loss studies of metal-ceramic interfaces in transition metal/alumina cermets
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J. Bruley, Julie A. Yeomans, X. Sun, P. A. Trusty, Rik Brydson, H. Müllejans, and Manfred Rühle
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Histology ,Materials science ,Analytical chemistry ,chemistry.chemical_element ,Cermet ,Hot pressing ,Pathology and Forensic Medicine ,Crystallography ,chemistry ,Transition metal ,Chemical bond ,Aluminium ,visual_art ,visual_art.visual_art_medium ,Ceramic ,Dissolution ,Diffusion bonding - Abstract
Summary Composites consisting of an alumina matrix and 20 vol.% transition metal (Ni or Fe) particles, prepared by hot pressing powder blends, have been studied using spatially resolved transmission electron energy-loss spectroscopy (EELS), and, to a lesser extent, by high-resolution electron microscopy (HREM). Particular attention was paid to the elucidation of the chemical bonding mechanisms at the metal-ceramic interface; EELS spectra from interfacial regions being obtained via a spatial difference technique. From both qualitative and quantitative interpretation of EELS near-edge structures, as well as observed HREM images, the data appear to be consistent with the presence of an Al-terminated alumina at the interface and the formation of direct transition metal – aluminium bonds in Al(O3M) (M = Ni or Fe) tetrahedral units, possibly as a result of the dissolution and interfacial reprecipitation of Al during processing. These results correlate well with similar model studies on diffusion-bonded Nb/Al2O3 interfaces and may, in the light of recent theoretical electronic structure calculations, have implications for the resultant interfacial bond strength in such materials.
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- 1995
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15. Structural and spectroscopic investigation of (111) twins in barium titanate
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Drago Kolar, W. Mader, Manfred Rühle, Aleksander Rečnik, and J. Bruley
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Valence (chemistry) ,General Chemical Engineering ,Analytical chemistry ,General Physics and Astronomy ,Molecular physics ,Spectral line ,chemistry.chemical_compound ,chemistry ,Oxidation state ,Transmission electron microscopy ,Ionization ,Barium titanate ,Spectroscopy ,Crystal twinning - Abstract
The coherent (111) twin boundary in BaTiO3 has been investigated using quantitative high-resolution transmission electron microscopy and spatially resolved electron-energy-loss spectroscopy (EELS). Lattice images under different defocusing conditions were obtained and compared with simulated images for different structural models. An excellent match between calculated and observed images was obtained only for the model where the Ba-O3 plane constitutes the twin boundary. The oxidation state of Ti at twin boundaries was interrogated by studying the near-edge structure of the L23 ionization edge of Ti using spatially resolved EELS. The difference between spectra taken from the bulk and those including the boundary indicates the presence of Ti in a reduced oxidation state at the boundary. The charge is compensated by oxygen vacancies Vo in the twin plane, which is therefore composed of Ba-O3-x[Vo]x instead of Ba-O3.
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- 1994
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16. Investigations of the chemistry and bonding at niobiumsapphire interfaces
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J. Bruley, Werner Mader, Joachim Mayer, Rik Brydson, H. Müllejans, Manfred Rühle, G. Gutekunst, and D. Knauss
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Materials science ,Band gap ,Mechanical Engineering ,Niobium ,chemistry.chemical_element ,Condensed Matter Physics ,Molecular physics ,Chemical bond ,chemistry ,Mechanics of Materials ,visual_art ,Monolayer ,visual_art.visual_art_medium ,Sapphire ,General Materials Science ,Ceramic ,Diffusion bonding ,Metallic bonding - Abstract
Spatially resolved electron energy-loss data have been recorded at the interface between niobium and sapphire (α-Al2O3), a model metal/ceramic couple. The spatial-difference technique is used to extract interface specific components of the energy-loss near-edge structure (ELNES), which are dependent on the chemistry and bonding across the interface. Multiple scattering calculations of aluminum, oxygen, and niobium clusters were performed to simulate the measured Al L2,3 ELNES. Two samples fabricated by different techniques were examined. The first interface was made by diffusion bonding pure crystals. Its interface spectrum is identified with tetrahedral coordination of the Al ions at the interface. The calculations match the experimental edge structures, supporting the notion of aluminum to niobium metal bonding and concurring with a structural model in which the basal plane of sapphire at the interface is terminated by a full monolayer (i.e., 67% excess) of aluminum. The second sample was produced by molecular beam epitaxy. The spectrum of this interface is consistent with an atomistic structure in which the interfacial basal plane of sapphire is terminated by oxygen. An unoccupied band of states within the band gap of Al2O3 is observed, signifying chemical bonding between metal and ceramic.
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- 1994
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17. Recent Attempts to Detect Magnesium in a Heavily Doped Sapphire Bicrystal by Spatially Resolved Electron Energy-Loss Spectroscopy
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Manfred Rühle, J. Bruley, Hans-Joachim Kleebe, and Thomas Höche
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Materials science ,Electron energy loss spectroscopy ,Spinel ,Doping ,Close-packing of equal spheres ,Analytical chemistry ,Mineralogy ,engineering.material ,Absorption edge ,Monolayer ,Materials Chemistry ,Ceramics and Composites ,engineering ,Grain boundary ,Spectroscopy - Abstract
Needle-shaped spinel precipitates in a matrix of heavily MgO-doped α-AI2O3 bicrystal containing a near Σ= 11 tilt boundary were examined by spatially resolved electron energy-loss spectroscopy. The Mg content was consistent with the precipitate being an alumina-rich spinel of composition MgO Σ(Al2O3)2. The Al and Mg K and L2.3 absorption edge structures were recorded. No evidence could be found for preferential Mg segregation to the tilt boundary. Using the precipitates as a calibration standard, a limit of detection equivalent to about 0.01 monolayer is deduced. Comparison of the Al-L2.3 edge recorded at the Σ= 11 boundary to that of the same boundary in undoped material suggests that the local structure is independent of Mg doping. The lack of Mg segregation to the Σ= 11 boundary is perhaps attributable to the low energy and close packing of this interface.
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- 1994
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18. TEM study of the structure and chemistry of a diamond/silicon interface
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Rishi Raj, Yujiun Tzou, Manfred Rühle, Frank Ernst, and J. Bruley
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Materials science ,Silicon ,Mechanical Engineering ,Material properties of diamond ,chemistry.chemical_element ,Diamond ,Substrate (electronics) ,Chemical vapor deposition ,engineering.material ,Condensed Matter Physics ,Nanocrystalline material ,Amorphous solid ,chemistry ,Chemical engineering ,Mechanics of Materials ,engineering ,General Materials Science ,High-resolution transmission electron microscopy - Abstract
The interface between diamond and silicon, fabricated by growing diamond films on (001) silicon by microwave plasma assisted chemical vapor deposition (MPACVD), was characterized by high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS). Two types of interface morphology were identified. Type A interfaces contain an amorphous transition layer composed of silicon, carbon, and oxygen; the diamond overgrowth on this layer consists of nanocrystalline grains with random orientations. Type B interfaces consist of large diamond grains having special orientations with respect to the silicon substrate, without an obvious presence of a glassy phase and with a much lower oxygen content than type A interfaces.
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- 1994
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19. Improvements in detection sensitivity by spatial difference electron energy-loss spectroscopy at interfaces in ceramics
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H. Müllejans and J. Bruley
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Chemistry ,business.industry ,Electron energy loss spectroscopy ,Diamond ,Electron ,engineering.material ,Molecular physics ,Atomic and Molecular Physics, and Optics ,Spectral line ,Electronic, Optical and Magnetic Materials ,Optics ,Impurity ,Scanning transmission electron microscopy ,engineering ,Grain boundary ,Sensitivity (control systems) ,business ,Instrumentation - Abstract
Many problems in materials science require that a small amount of an impurity is detected, for example the segregation of such an impurity to an internal interface. For such inhomogeneous specimens two electron energy-loss spectra can be recorded: one from the interface and one from the nearby matrix. The second spectrum serves as a reference and can be subtracted from the first to remove the background and to reveal the excess of an element at the internal boundary. This method is labelled “spatial difference”. In this paper spatial difference is compared to other methods of background removal in electron energy-loss spectra. After a general discussion of the methods their detection sensitivity is compared quantitatively by calculating the signal-to-noise ratio with a simple numerical model. The results are compared to experimental results for the detection of Ca at grain boundaries in alumina and N inclusions in diamond. It is found that spatial difference has the highest signal-to-noise ratio in these model experiments and therefore improves the detection sensitivity as compared to the other methods. Spatial difference of inhomogeneous specimens in a scanning transmission electron microscope is straightforward. A clear advantage of the spatial difference involves the study of near-edge structure of the impurity element, yielding information on the atomistic structure and chemical bonding of internal interfaces.
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- 1994
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20. HREM and AEM studies of Yb2O3-fluxed silicon nitride ceramics with and without CaO addition
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Manfred Rühle, J. Bruley, and Hans-Joachim Kleebe
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Materials science ,Mineralogy ,Intergranular corrosion ,Microstructure ,Amorphous solid ,law.invention ,chemistry.chemical_compound ,Silicon nitride ,chemistry ,law ,visual_art ,Materials Chemistry ,Ceramics and Composites ,visual_art.visual_art_medium ,Ceramic ,Crystallization ,Composite material ,Layer (electronics) ,Solid solution - Abstract
The grain-boundary microstructure and interface chemistry of Yb2O3/Al2O3-fluxed sintered Si3N4 materials with and without the addition of CaO has been investigated by means of high-resolution and analytical electron microscopy. Each Si3N4 grade examined, exhibited a thin amorphous intergranular layer at both homophase and heterophase boundaries. The presence of calcium within this amorphous layer is confirmed in the CaO-doped materials. Furthermore, no solid solution of CaO within the Si3N4-matrix grains could be detected. The observed variability in the grain-boundary film thickness appears to be closely related to changes in the glass composition, in particular to the Ca content. The addition of CaO resulted in a widening of the intergranular film of up to 0·4 nm. Moreover, postsintering heat-treatment, which induces crystallization of the secondary phase pockets, led to only small changes in the intergranular film thickness of 0·1 nm when compared to the as-sintered specimens, for both CaO-doped and undoped materials.
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- 1994
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21. Variable magnification dual lens electron holography for semiconductor junction profiling and strain mapping
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Yun-Yu Wang, A. Domenicucci, J. Bruley, and J. Li
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Physics ,Diffraction ,business.industry ,Holography ,Electrons ,Electron ,Dark field microscopy ,Atomic and Molecular Physics, and Optics ,Electron holography ,Electronic, Optical and Magnetic Materials ,law.invention ,Lens (optics) ,Optics ,Tilt (optics) ,Semiconductor ,Semiconductors ,law ,business ,Instrumentation ,Lenses - Abstract
Dual lens operation for electron holography, which was developed previously (Wang et al., Ultramicroscopy 101 (2004) 63–72; US patent: 7,015,469 B2 (2006)), is re-investigated for bright field (junction profiling) and dark field (strain mapping) electron holography using FEI instrumentation (i.e. F20 and Titan). It is found that dual lens operation provides a wide operational range for electron holography. In addition, the dark field image tilt increases at high objective lens current to include Si 〈0 0 4〉 diffraction spot. Under the condition of high spatial resolution (1 nm fringe spacing), a large field of view (450 nm), and high fringe contrast (26%) with dual lens operation, a junction map is obtained and strain maps of Si device on 〈2 2 0〉 and 〈0 0 4〉 diffraction are acquired. In this paper, a fringe quality number, N ′, which is number of fringe times fringe contrast, is proposed to estimate the quality of an electron hologram and mathematical reasoning for the N ′ number is provided.
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- 2011
22. Spatially resolved electron energy-loss near-edge structure analysis of a near Σ = 11 tilt boundary in sapphire
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J. Bruley
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Chemistry ,business.industry ,Coordination number ,chemistry.chemical_element ,Electron ,Molecular physics ,Spectral line ,XANES ,Condensed Matter::Materials Science ,Optics ,Aluminium ,Sapphire ,Grain boundary ,business ,Absorption (electromagnetic radiation) ,Instrumentation - Abstract
Spatially resolved electron energy-loss spectra have been recorded from the same E = 11 grain boundary of a high purity sapphire (03B1 - Al2O3) bi-crystal that had previously been examined by high resolution electron microscopy. The energy-loss near-edge structure (ELNES) on the aluminium L2,3 edge of the bulk 03B1 - Al2O3 is consistent with previously published X-ray absorption near-edge spectra (XANES). The presence of the grain-boundary introduces additional fine structure on the L2,3 edge, which is extracted from the dominant bulk spectrum using the chemical-standard "difference" method. A comparison with various spectral "fingerprints" suggests that the structural environment of the Al cations within the boundary plane has a reduced point-group symmetry and coordination number. Quantitative analyses of spectral intensities indicate that the equivalent of a full monolayer of Al cations is involved in the structural change at the boundary. These experimental observations are consistent with a recently calculated low energy relaxed grain-boundary structure.
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- 1993
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23. Dual Lens Electron Holography for High Spatial Resolution Junction and Strain Mapping of Semiconductor Devices
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Y.Y. Wang and J. Bruley
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Lens (optics) ,Optics ,Materials science ,law ,business.industry ,High spatial resolution ,Optoelectronics ,Strain mapping ,Semiconductor device ,business ,Instrumentation ,Electron holography ,law.invention - Published
- 2014
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24. Detection of nitrogen at {100} platelets in a type IaA/B diamond
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J. Bruley
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Chemistry ,Analytical chemistry ,Diamond ,chemistry.chemical_element ,engineering.material ,Condensed Matter Physics ,Nitrogen ,Impurity ,Monolayer ,engineering ,Platelet ,Spectroscopy ,Carbon ,Quantitative analysis (chemistry) - Abstract
The {100} platelets of a type IaA/B diamond have been examined by spatially resolved electron-energy-loss spectroscopy. It is demonstrated unambiguously that nitrogen is present at these planar defects but in low concentrations. A quantitative analysis of the data reveals that the atomic density of the nitrogen is 0·23 (±0·14)atoms per a 2 0, that is about one tenth of a monolayer. This amount is significantly less than predicted by the nitrogen-containing structural models. It is concluded that the platelets are most likely to be composed of carbon and contain nitrogen as a major impurity species.
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- 1992
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25. Formation of compositionally abrupt axial heterojunctions in silicon-germanium nanowires
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C.-Y. Wen, Jerry Tersoff, Frances M. Ross, Suneel Kodambaka, J. Bruley, Mark C. Reuter, and Eric A. Stach
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Multidisciplinary ,Materials science ,Silicon ,business.industry ,Nanowire ,chemistry.chemical_element ,Germanium ,Heterojunction ,Nanotechnology ,Silicon-germanium ,chemistry.chemical_compound ,chemistry ,Quantum dot ,Optoelectronics ,Vapor–liquid–solid method ,business ,Eutectic system - Abstract
Sharp Nanowires The potential for using nanowires in devices can be limited by the ability to synthesize them from two or more materials while maintaining compositional purity at the interfaces. Instead of using liquid droplets at the eutectic point when the melting point is at a minimum, Wen et al. (p. 1247 ) show that generating the wires at solid alloy catalysts allows fabrication of silicon germanium wires with atomically sharp interfaces. The system works well because an AlAu alloy composition was chosen in which Si and Ge have a low solubility but which have a high enough eutectic temperature so that nanowire growth is not limited by the reactivity of the Si and Ge precursors.
- Published
- 2009
26. Characterization of CVD-hydrogenated diamondlike thin films on silicon by EELS, RBS/channeling and nuclear reaction analysis
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J. Bruley, Peter Madakson, and Joyce C. Liu
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Nuclear and High Energy Physics ,Materials science ,Hydrogen ,Silicon ,Electron energy loss spectroscopy ,Analytical chemistry ,chemistry.chemical_element ,Substrate (electronics) ,Partial pressure ,chemistry ,Nuclear reaction analysis ,Thin film ,Spectroscopy ,Instrumentation - Abstract
Thin diamondlike films, deposited on (100) Si, have been examined by electron energy loss spectroscopy (EELS), Rutherford backscattering spectroscopy (RBS) and nuclear reaction analysis. Results indicate that films deposited at high partial pressures of H2, which have been found to be softer than those deposited at low partial pressures, have higher concentrations of oxygen but similar concentrations of hydrogen within their bulk. It is proposed that the oxygen is bound to the carbon matrix, thus modifying the extended sp2 network. Analysis of the substrate indicates a damaged region at the top surface of the Si.
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- 1990
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27. Nanostructure and chemistry of a (100)MgO/(100)GaAs interface
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W.-Y. Hsu, Manfred Rühle, Frank Ernst, J. Bruley, Rishi Raj, and Susanne Stemmer
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Physics and Astronomy (miscellaneous) ,business.industry ,Oxide ,Substrate (electronics) ,Sputter deposition ,Microstructure ,Epitaxy ,Nanocrystalline material ,Amorphous solid ,chemistry.chemical_compound ,Crystallography ,chemistry ,Optoelectronics ,business ,Single crystal - Abstract
High‐resolution transmission electron microscopy (TEM) shows that MgO films, grown on (001) GaAs by magnetron sputtering, are single crystal with a cube‐on‐cube relationship with the substrate, even though they are separated from the substrate by an amorphous interlayer. Scanning TEM–energy dispersive x‐ray and scanning TEM–electron energy loss spectroscopy analysis of the interlayer shows that it consists of the native oxide of GaAs as well as nanocrystalline MgO. It is proposed that epitaxial MgO nucleated at pin holes produced by volatilization of the native oxide.
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- 1994
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28. Synthesis and characterization of TiO/sub 2/ films for deep trench capacitor applications
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Rajarao Jammy, J. Bruley, L. Woods, A. Michaelis, J. Shepard, K. Wong, U. Schroeder, and P. DeHaven
- Subjects
Materials science ,Annealing (metallurgy) ,business.industry ,chemistry.chemical_element ,Dielectric ,Capacitance ,Titanium nitride ,law.invention ,Capacitor ,chemistry.chemical_compound ,Silicon nitride ,chemistry ,law ,Titanium dioxide ,Optoelectronics ,business ,Titanium - Abstract
Traditionally, DRAM storage capacitors have employed silicon dioxide, silicon nitride, or a combination of both as the capacitor dielectric. With the advent of smaller structures however, gains in capacitance made via the utilization of thinner films and/or enhanced-surface-area-structures are offset by increased leakage current or added processing complexity. In an effort to maintain capacitance as the ground rules shrink, work has been conducted on the synthesis and integration of titanium dioxide films into deep trench capacitors. For this investigation, films between 150 and 300 /spl Aring/ thick have been synthesized via the high temperature oxidation of titanium nitride at temperatures between 600 to 900/spl deg/C. Microstructural and electrical characterization has been performed on both blanket films and deep trench structures. Results show the films to be polycrystalline-rutile with a dielectric constant of about 30. Leakage current densities measured at 1 V were found to increase from values on the order of 10/sup -8/ A/cm/sup 2/ as grown to 10/sup -6/ A/cm/sup 2/ upon annealing at 1050/spl deg/C for 3 minutes in inert ambient. TEM/SEM analyses have illustrated the step coverage of the deposition technique and results indicate film conformality to be better than 90%.
- Published
- 2002
- Full Text
- View/download PDF
29. 'Natural' and 'man-made' platelets in type-la diamonds
- Author
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J. Bruley, W. Luyten, G. Van Tendeloo, and I. Kiflawi
- Subjects
Absorption spectroscopy ,Infrared ,Chemistry ,Annealing (metallurgy) ,General Chemical Engineering ,Physics ,Analytical chemistry ,General Physics and Astronomy ,Infrared spectroscopy ,Microstructure ,law.invention ,Crystallography ,law ,Platelet ,Electron microscope ,Spectroscopy - Abstract
'Natural' platelets are planar defects in {001} planes found in natural type-IaA/B diamonds. 'Man-made' platelets are platelets formed in the laboratory by annealing type-IaA diamonds at temperatures over 2500 degrees C. Careful study shows that the infrared (IR) spectra of the 'man-made' platelets are different from the IR spectra of 'natural' platelets. High-temperature (T greater than or equal to 2000 degrees C) annealing of platelets containing type-IaA/B diamonds modifies the IR absorption spectrum owing to the 'natural' platelets and makes it similar to the IR spectrum of the 'man-made' platelets. It is suggested that such high-temperature annealing changes the structure of the 'natural' platelets. The changes are too subtle to be detected by electron microscopy techniques. Topographic electron-energy-loss spectroscopy shows that platelets contain nitrogen at an average density of 0.7 atoms per a(0)(2); however, high-temperature annealing does not seem to affect the concentration of the nitrogen in the platelets.
- Published
- 1998
30. Analysis of Layered Structures at High Spatial Resolution Using Energy Filtered Imaging
- Author
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P.L. Flaitz and J. Bruley
- Subjects
Software ,Optics ,Semiconductor ,Materials science ,Dimension (vector space) ,business.industry ,Gate oxide ,Line (geometry) ,business ,Spatial analysis ,Image resolution ,Energy (signal processing) - Abstract
The development of energy filtered imaging systems for the TEM has opened new approaches to analyzing structures with very small dimensions. One of the benefits of such systems is the ability to form an EELS spectrum image containing energy information on one axis and spatial information on the other axis. By dissecting such an image in the spatial dimension, it is possible to generate a line profile across a layered structure at high spatial dimension without the need for a small probe. We have applied this approach to two structures typical of semiconductors, the Si/SiO2/Si interfaces in a gate oxide and the Ti/SiO2 interface for Al barrier metallization, which illustrate the spatial resolution possible with this technique. To analyze the spectrum images, the element specific near edge structure (ELNES) data are processed by conventional EELS background routines and multivariate statistical techniques using MATLAB software to extract both profiles of principal bonding components and composition.
- Published
- 1998
- Full Text
- View/download PDF
31. Investigations of the Bonding Changes Associated with Grain Boundary Embrittlement
- Author
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David B. Williams, Vicki J. Keast, and J. Bruley
- Subjects
Electron energy ,Materials science ,Edge structure ,Impurity ,Metallurgy ,Grain boundary ,Electronic structure ,Embrittlement - Abstract
The embrittlement of materials through the segregation of impurities to the grain boundaries is a common and industrially important problem. Despite considerable investigation, the mechanism by which the impurity elements cause embrittlement is not well understood. A change in the electron energy loss near edge structure (ELNES) has been observed at Cu grain boundaries containing Bi. This result provides experimental evidence that a change in the electronic structure at the grain boundary is responsible for embritdement.
- Published
- 1996
- Full Text
- View/download PDF
32. Deposition And Characterization Of Silicon And Carbon Nitride
- Author
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Jerome J. Cuomo, S. P. Bozeman, J. Bruley, D. A. Tucker, M. J. Powers, S. M. Camphausen, John J. Hren, and A. F. Myers
- Subjects
Auger electron spectroscopy ,chemistry.chemical_compound ,Materials science ,Silicon ,chemistry ,Scanning electron microscope ,Transmission electron microscopy ,Electron energy loss spectroscopy ,Analytical chemistry ,chemistry.chemical_element ,Selected area diffraction ,Inductively coupled plasma ,Carbon nitride - Abstract
We attempted to deposit carbon nitride films on flat Si (111) substrates and on sharp -oriented silicon needles in a radio frequency (rf) inductively coupled plasma system utilizing a graphite source and a nitrogen plasma. The resultant polycrystalline films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Auger electron spectroscopy (AES), and electron energy loss spectroscopy (EELS). Both selected area electron diffraction (SAED) and lattice imaging were used to identify and characterize the particles, which grew as faceted crystals up to 1 Rm in size. From SAED, high resolution TEM, and EELS, it was found that the particles on the Si needles were α-Si3N4 and that those on the Si wafer were mostly β-Si3N4 and β-C3N4, with some β-C3N4 possible. Auger quantitative analysis suggests that β-C3N4 could be stabilized by the presence of silicon, resulting in a material with compositions CxSiyNz.
- Published
- 1995
- Full Text
- View/download PDF
33. Carbon Nitride Films Using a Filtered Cathodic ARC
- Author
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D. A. Tucker, J. Bruley, Jerome J. Cuomo, and Scott.M. Camphausen
- Subjects
Diffraction ,Auger electron spectroscopy ,Materials science ,Analytical chemistry ,chemistry.chemical_element ,Nitrogen ,Cathodic protection ,law.invention ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Optical microscope ,law ,Cathodic arc deposition ,symbols ,Raman spectroscopy ,Carbon nitride - Abstract
In this study a high N2 pressure has been used to enhance the N incorporation into CN films produced by a shock plasma deposition method. auger spectroscopy indicates that increasing the nitrogen pressure from 0.1 atm to 10 atm results in an increase of nitrogen incorporation into CN films to a maximum of 43 at.%. Nitrogen distribution varies across the surface of the deposit, showing an increase of nitrogen content with depth in the center of the deposition and a decrease with depth at points away from the center. SEM and optical microscopy indicate that under increased nitrogen pressure the grain structure becomes finer. Raman spectra contain sharp peaks characteristic of a distinct crystalline CN phase. TEM diffraction patterns for the films produced under N2 pressure in the range of 0.05-0.1 atm unambiguously show the presence of micron-sized crystals displaying a cubic symmetry, and not the predicted β-Si3N4 type structure. PEELS data suggest that in the crystalline phase a significant fraction of the nitrogen atoms have sp2 trigonal bonds and there is a significant degree of sp3 character for the carbon atoms.
- Published
- 1995
- Full Text
- View/download PDF
34. High Resolution Electron Microscopy Studies on Silicon Nitride Ceramics
- Author
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J. S. Vetrano, Hans-Joachim Kleebe, Isao Tanaka, J. Bruley, M. K. Cinibulk, and Manfred Rühle
- Subjects
Materials science ,Sintering ,Intergranular corrosion ,Characterization (materials science) ,law.invention ,Amorphous solid ,chemistry.chemical_compound ,Silicon nitride ,chemistry ,law ,visual_art ,visual_art.visual_art_medium ,Ceramic ,Electron microscope ,Composite material ,Chemical composition - Abstract
High-resolution electron microscopy (HREM) was used to study interfaces in Si3N4 materials on a sub-nanometer scale. Amorphous secondary phases are present at multigrain junctions, owing to the liquid-phase sintering process involved. In addition, all Si3N4-grains are separated by a continuous amorphous intergranular film. A control of these amorphous films is most desirable and hence emphasis was placed on the characterization of both structural and compositional information of interganular films. Different TEM techniques can be applied for the detection and determination of intergranular-film thickness, however, the most accurate results are obtained by the lattice-imaging technique. Statistical analyses of a number of grain-boundary films provided an experimental verification that the film thickness is constant. High-purity Si3N4 materials with SiO2 as the only additive revealed a film thickness of 1.0 nm, independent of SiO2-volume fraction. Si3N4 materials with different metal-oxide additions showed differences in thickness and chemical composition of the intergranular films, as revealed by analytical electron microscopy (AEM) with high spatial resolution. The results on film thickness (HREM) strongly suggest a dependence of film thickness on its chemical composition. So far, no experimental observations suggest a dependence of film thickness on additive-volume fraction. During an appropriate post-sintering heat treatment crystalline secondary phases form at triple-grain regions. Depending on the secondary phases formed, interface chemistry can be altered and hence grain-boundary film thickness be changed.
- Published
- 1994
- Full Text
- View/download PDF
35. Quantitative Electronic Structure Analysis of α-AL203 Using Spatially Resolved Valence Electron Energy-Loss Spectra
- Author
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J. Bruley, P. A. Morris, Haral MÜllejans, and Roger H. French
- Subjects
Materials science ,Valence (chemistry) ,Critical point (thermodynamics) ,Band gap ,Scanning transmission electron microscopy ,Grain boundary ,Electronic structure ,Atomic physics ,Valence electron ,Spectroscopy - Abstract
Valence electron energy-loss (EEL) spectroscopy in a dedicated scanning transmission electron microscope (STEM) has been used to study the Σ11 grain boundary in α-A12O3 in comparison with bulk α-A12O3. The interband transition strength was derived by Kramers-Kronig analysis and the electronic structure followed from quantitative critical point (CP) modelling. Thereby differences in the acquired spectra were related quantitatively to differences in the electronic structure at the grain boundary. The band gap at the boundary was slightly reduced and the ionicity increased. This work demonstrates for the first time that quantitative analysis of spatially resolved (SR) valence EEL spectra is possible. This represents a new avenue to electronic structure information from localized structures.
- Published
- 1994
- Full Text
- View/download PDF
36. Compositions and Thicknesses of Grain Boundary Films in Ca-Doped Silicon Nitride Ceramics
- Author
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Hans-Joachim Kleebe, Hui Gu, Manfred Rühle, Rowland M. Cannon, Michael J. Hoffmann, David R. Clarke, Isao Tanaka, and J. Bruley
- Subjects
Materials science ,Dopant ,Doping ,Analytical chemistry ,Intergranular corrosion ,Amorphous solid ,chemistry.chemical_compound ,Silicon nitride ,chemistry ,Impurity ,visual_art ,visual_art.visual_art_medium ,Grain boundary ,Ceramic - Abstract
Nanobeam analytical electron microscopy and high-resolution electron microscopy have been used to characterize both the local composition as well as the thickness of the amorphous intergranular silicate-rich film in high-purity Si3N4 ceramics doped with different levels of Ca impurities. Grain boundary films could be detected in all ceramics. The films always contained Si (cation) and O and N (anions). Ca was detected at both grain boundary junctions and triple junctions for all materials doped with different levels of Ca. The thickness h of the intergranular films depends sensitively on the Ca content. In undoped materials h is 1.0±0.1 nm. With increasing Ca content the thickness h decreased for a dopant of 80 ppm Ca but increased with further additions of Ca. Variations in film thickness and composition can be semi-quantitatively understood in terms of different long-range interatomic forces acting normal to the film.
- Published
- 1994
- Full Text
- View/download PDF
37. Combining Eels and Angle-Resolved Aes to Measure Shallow Profiles of Thin Nitrided Oxide Films on Si
- Author
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J. Bruley, H. Wildman, and A. Paterson
- Subjects
chemistry.chemical_compound ,Materials science ,chemistry ,Inorganic chemistry ,Analytical chemistry ,Oxide ,Measure (physics) ,Instrumentation ,Nitriding - Published
- 2002
- Full Text
- View/download PDF
38. Electron energy-loss spectroscopy (EELS) ; comparison with X-ray analysis
- Author
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J. Bruley and H. Müllejans
- Subjects
010302 applied physics ,X-ray spectroscopy ,business.industry ,Chemistry ,Electron energy loss spectroscopy ,General Physics and Astronomy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Engineering physics ,Analytical electron microscopy ,Optics ,[PHYS.HIST]Physics [physics]/Physics archives ,0103 physical sciences ,0210 nano-technology ,Spectroscopy ,business ,X ray analysis - Abstract
Analytical electron microscopy offers two main techniques of interest to materials science : electron energy-loss spectroscopy (EELS) and energy-dispersive x-ray analysis (EDX). The scientist is confronted with the choice of one of the two for the problem under consideration, although it is possible to employ both simultaneously. It is therefore important to know what to expect from each of the two techniques to assess which one is more likely to yield the desired information. Here both are compared to provide help in making that decision. The various aspects are illustrated with recent applications of both techniques in the research on interfaces in ceramics. Emphasis is put on the analysis of additional information contained in EELS, because this contributes to the understanding of bonding and chemistry inside the specimen.
- Published
- 1993
- Full Text
- View/download PDF
39. Nucleation of Special Orientations During Heteroepitaxial Growth of Diamond on Silicon
- Author
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M. Riihle, J. Bruley, Frank Ernst, Rishi Raj, and Yujiun Tzou
- Subjects
Materials science ,Condensed matter physics ,Silicon ,Plane (geometry) ,Nucleation ,chemistry.chemical_element ,Diamond ,engineering.material ,Nanocrystalline material ,Amorphous solid ,chemistry ,Phase (matter) ,engineering ,High-resolution transmission electron microscopy - Abstract
The orientation relationships that develop in the early stages of diamond nucleation on silicon, were examined by TEM and HRTEM. The films were produced by microwave plasma assisted CVD. Two types of interface regions were identified. In one case an amorphous interlayer was observed and the nucleation of diamond was nanocrystalline. In the second case the interface was apparently free from a second phase; in these instances the diamond and silicon lattices formed special orientations. The special orientations were identified as the following: (a) 60 degree rotation, (b) 90 degree rotation and (c) diamond {111} plane tilted 6 degrees from silicon {220} plane. The orientation relationships are analyzed in terms of geometric models that seek the best fit between the diamond and silicon lattices at the interface plane.
- Published
- 1993
- Full Text
- View/download PDF
40. Applications of Multi-Variate Statistical Analysis of Spectrum Images to Microelectronic Devices
- Author
-
J. Bruley
- Subjects
Random variate ,Computer science ,business.industry ,Spectrum (functional analysis) ,Microelectronics ,Pattern recognition ,Statistical analysis ,Artificial intelligence ,business ,Instrumentation - Abstract
It is not uncommon for an electrical failure in a microelectronic device to be traced back to an individual resistive contact, such as a W contact lined by TiN to the underlying metal silicide [1]. Identifying the root cause of the defective cell then requires the capability of extracting interfacial chemistry and microstructure with near atomic resolution, which is achieved by recording EELS and EDX data either along 1-d lines or from 2-d arrays. EELS data are characterized by intrinsically low signal-to-background ratios and plural inelastic-scattering effects, which presents a challenge to the reliability of the methods used to extract quantitative information from a spectrum image. Commercially available software packages by Emispec and Gatan currently provide routines for power-law or polynomial background fits and allow the net counts under peaks or edges to be determined from each pixel. in both cases each spectrum in the series is processed in the same manner.
- Published
- 2001
- Full Text
- View/download PDF
41. High-Resolution Electron Microscopy Observations of Grain-Boundary Films in Silicon Nitride Ceramics
- Author
-
Rowland M. Cannon, Hans-Joachim Kleebe, Michael J. Hoffmann, J. Bruley, Manfred Rühle, Isao Tanaka, Michael K. Cinibulk, and David R. Clarke
- Subjects
Materials science ,Doping ,Characterization (materials science) ,law.invention ,chemistry.chemical_compound ,symbols.namesake ,Silicon nitride ,chemistry ,Transmission electron microscopy ,law ,visual_art ,symbols ,visual_art.visual_art_medium ,Grain boundary ,Ceramic ,Composite material ,Electron microscope ,van der Waals force - Abstract
Characterization of silicon nitride ceramics by transmission electron microscopy (TEM) provides structural and compositional information on intergranular phases necessary to elucidate the factors that can influence the presence and thickness of grain-boundary films. Different TEM techniques can be used for the detection and determination of intergranular-film thickness, however, the most accurate results are obtained by high-resolution electron microscopy (HREM). HREM studies were applied, in conjunction with analytical electron microscopy, to investigate the correlation between intergranular-phase composition and film thickness. Statistical analyses of a number of grain-boundary films provided experimental verification of a theoretical equilibrium film thickness. Model experiments on a high-purity Si3N4 material, doped with low amounts of Ca, suggest the presence of two repulsive forces, a steric force and a force produced by an electrical double layer, that may act to balance the attractive van der Waals force necessary to establish an equilibrium film thickness.
- Published
- 1992
- Full Text
- View/download PDF
42. Energy Dispersive X-Ray (EDX) and Electron Energy-Loss (EELS) Spectroscopic Mapping of Microelectronic Devices
- Author
-
P. Flaitz and J. Bruley
- Subjects
Materials science ,Electron energy ,business.industry ,X-ray ,Microelectronics ,Optoelectronics ,business ,Instrumentation ,Energy (signal processing) - Abstract
Many crucial measurements in the semiconductor industry involve determining the root cause of an electrical failure, often requiring the capability of extracting microstructural and chemical information with nanometer resolution [1]. The microanalysis is achieved by stepping the focused probe over the region of interest in STEM mode and recording an EDX and EELS spectrum at each pixel. Even for relatively modest image sizes, the resultant spectrum-image may consist of more than 10,000 spectra. With such large data sets, the prospect of manually inspecting and quantifying each spectrum in real-time is impossible and even automatic background modeling followed by peak area integration over selected spectral regions-of-interest can be excessively time consuming. Other methods to extract useful physical information include “fingerprinting” characteristic ELNES shapes to known compounds or bonding environments, multiple least squares regression to a relatively small set of suspected components or peak-fitting to model systematic changes in electronic density of states.
- Published
- 2000
- Full Text
- View/download PDF
43. Germanium Concentration Profiles Across Interfaces And Close To Dislocations In Cvd Si1−xGex-on-Si Junctions
- Author
-
Frank Ernst, K. Ljutovich, and J. Bruley
- Subjects
Crystallography ,Materials science ,chemistry ,Condensed matter physics ,chemistry.chemical_element ,Nanometre ,Germanium ,Dislocation ,Deposition process ,Line (formation) - Abstract
This work concerns a microanalytical study of CVD heteroepitaxial Si1–xGex/Si junctions with x ranging from 0.05 to 0.22. We observe that rather than being chemically abrupt, the width of the interface ranges between 200nm and 2μm with a band of misfit dislocations occupying the same region. Furthermore, the average separation of the dislocations is 2 or 3 times greater than predicted by b/δ considerations. Close scrutiny at individual dislocations within the interface region reveals a local deficit of several hundred Ge atoms per nanometer of dislocation line. It is proposed that the composition profile is rapidly spread by inter-diffusion along dislocations during the deposition process.
- Published
- 1991
- Full Text
- View/download PDF
44. (Under)Graduate Teaching Using Internet Access to Electron Microscopes
- Author
-
Lawrence F. Allard, J. Bruley, David B. Williams, and Edgar Voelkl
- Subjects
Class (computer programming) ,Focus (computing) ,Engineering drawing ,Commercial software ,business.product_category ,Computer science ,business.industry ,Phonics ,Sample (graphics) ,Software ,Internet access ,The Internet ,business ,Instrumentation - Abstract
The Lehigh University is presently offering direct access to top of the line electron microscopes at ORNL via the Internet for one graduate and one undergraduate course (Advanced TEM, Electron Microscopy & Microanalysis). The students at Lehigh have the opportunity to themselves control the Hitach HF-2000 FEG TEM. The controls presently include change of magnification and focus, moving the sample and correction for astigmatism. In this way, the students can collect high resolution lattice images of various materials and study e.g., the effects of changing focus on lattice images (contrast reversal). While the students at Lehigh can sit in the class room and run the instrument in broad daylight and communicate freely without disturbing the instrument by phonics, the instrument itself is protected from misuse through several layers of hardware and software.This new way of teaching EM courses has become possible through recent advances in computer hardware (live-time Fourier transforms (FFTs)) and software. A commercial software package TimbuktuPro provides remote access to the computer at the HF-2000 at ORNL which controls the instrument as well as the slow-scan CCD-cameras (Gatan, model 794) attached to the instrument.
- Published
- 1997
- Full Text
- View/download PDF
45. Application of Nano-Scale Eels Spectrum Lines To Grain Boundaries
- Author
-
J. Cho, H. M. Chan, J. Bruley, and M. P. Hanner
- Subjects
Materials science ,Condensed matter physics ,Grain boundary ,Instrumentation ,Nanoscopic scale ,Spectral line - Abstract
Polycrystals containing small quantities of impurity can exhibit dramatically different properties from that of the pure material. One example of this is the tenfold increase in the creep resistance of Y or La doped alumina relative to ultra-pure alumina. Such changes are correlated to grain boundary segregation, however the segregant’s potency to influence properties remains unexplained. Determining the driving force to segregation only partially addresses this issue. A full understanding must take account of the chemical bonding and structural changes occurring at the boundary after segregation. The purpose of this study is to observe the electronic structure associated with the segregating species using EELS spectrum-line profiling. This is accomplished by monitoring the segregation profile along with the characteristic near edge absorption fine structures which reflect changes in the localized density of unoccupied states along that profile. In these experiments a finely focused beam was sequentially stepped across the boundary of interest and a spectrum recorded at each step.
- Published
- 1997
- Full Text
- View/download PDF
46. Identification of Metal-Impurity Gettering Sites in Silicon Formed by Supersaturation Boron Implantation and Annealing Using HRTEM and STEM Micro Analysis
- Author
-
G. A. Petersen, T. J. Headley, Joseph R. Michael, J. Bruley, T. L. Aselage, and S. M. Myers
- Subjects
Supersaturation ,Materials science ,Silicon ,Annealing (metallurgy) ,Metallurgy ,chemistry.chemical_element ,Metal ,chemistry ,Impurity ,Getter ,visual_art ,visual_art.visual_art_medium ,Boron ,High-resolution transmission electron microscopy ,Instrumentation - Abstract
Future Si microelectronic devices will require increasingly stringent limits on transition-metal impurities. There is thus a need to develop new methods for impurity gettering that rely on gettering sites that are active for arbitrarily small impurity concentrations, below the characteristic solid solubility at which metal suicides precipitate. These sites must also be highly preferred relative to solution sites in the Si matrix even at elevated temperatures. One such method has been developed that is also expected to be compatible with front (device) side gettering enabling smaller diffusion lengths for lower processing temperatures. This method involves boron implantion in the front side to levels above the boron-saturation limit and annealing to generate the gettering sites. The gettering layer is introduced at a depth beneath the device zone through appropriate choice of implantation energy. SIMS compositional profiling shows transition metals are strongly gettered within the boron-supersaturated layer. The purpose of this study was to identify the structure and composition of the gettering sites within the boron-supersaturated layer.
- Published
- 1997
- Full Text
- View/download PDF
47. STEM investigation of the chemistry and bonding changes associated with the grain boundary embrittlement of Cu by Bi
- Author
-
David B. Williams, J. Bruley, and Vicki J. Keast
- Subjects
Chemistry ,Metallurgy ,Grain boundary ,General Medicine ,Embrittlement - Abstract
It has long been known that trace amounts of Bi can embrittle Cu after appropriate heat treatments. The Bi segregates to the grain boundaries and weakens them such that failure occurs through intergranular fracture without plastic deformation. This behavior is demonstrated in the scanning electron micrograph of a typical Cu-Bi fracture surface in Figure 1. It is known that the Bi extends for only a few atomic layers into the grains on either side of the grain boundary. This narrow segregation width was been confirmed using Energy Dispersive X-ray Spectroscopy (EDS) on a VG HB603 STEM. Figure 2 shows the ratio of Bi to Cu as the probe is stepped across the grain boundary.The segregation behavior is well understood, however it is not yet properly understood how the Bi causes embrittlement once it is at the grain boundaries. The Bi must change the bonding at the boundaries so that the boundaries become weak and hence the most likely fracture path. The Electron Energy Loss Near Edge Structure (ELNES) coupled with the small probes and high current density available in a field emission STEM can provide information about the localized electronic structure and hence bonding at grain boundaries. Previous investigations indicated that the near edge structure of Cu was altered at the grain boundaries due to the presence of Bi.
- Published
- 1996
- Full Text
- View/download PDF
48. EELS Measurement of the Local Electronic Structure of Copper Atoms Segregated to Aluminum Grain Boundaries
- Author
-
S. J. Splinter, R. Rosenberg, P.E. Batson, D.A. Smith, and J. Bruley
- Subjects
Materials science ,chemistry ,Aluminium ,Chemical physics ,chemistry.chemical_element ,Grain boundary ,General Medicine ,Electronic structure ,Copper - Abstract
It has long been known that the addition of Cu to Al interconnects improves the resistance to electromigration failure. It is generally accepted that this improvement is the result of Cu segregation to Al grain boundaries. The exact mechanism by which segregated Cu increases service lifetime is not understood, although it has been suggested that the formation of thin layers of θ-CuA12 (or some metastable substoichiometric precursor, θ’ or θ”) at the boundaries may be necessary. This paper reports measurements of the local electronic structure of Cu atoms segregated to Al grain boundaries using spatially resolved EELS in a UHV STEM. It is shown that segregated Cu exists in a chemical environment similar to that of Cu atoms in bulk θ-phase precipitates.Films of 100 nm thickness and nominal composition Al-2.5wt%Cu were deposited by sputtering from alloy targets onto NaCl substrates. The samples were solution heat treated at 748K for 30 min and aged at 523K for 4 h to promote equilibrium grain boundary segregation. EELS measurements were made using a Gatan 666 PEELS spectrometer interfaced to a VG HB501 STEM operating at 100 keV. The probe size was estimated to be 1 nm FWHM. Grain boundaries with the narrowest projected width were chosen for analysis. EDX measurements of Cu segregation were made using a VG HB603 STEM.
- Published
- 1996
- Full Text
- View/download PDF
49. Effect of thickness variations on EELS spatial-difference profiles
- Author
-
J. Bruley and D. B. Williams
- Subjects
Materials science ,Mineralogy ,General Medicine ,Spatial difference - Abstract
This paper concerns the influence of sample thickness on spatial-difference spectra, and seeks to identify if an interface dependent signal may be generated as an artifact of grain boundary grooving. The spatial-difference profiling technique may be used to identify variations in composition and electronic structure across interfaces at sub-nanometer length scales. The signal-to-background ratios and hence visibility of small changes to the near-edge structure and edge intensities are enhanced using this technique by removing intense energy dependent backgrounds. These backgrounds are assumed to be only slowly varying with respect to the electron probe position. A spatial-difference spectrum is generated from the difference between two spectra after suitable normalization or scaling. This scaling is achieved by either matching intensities of the background prior to a characteristic absorption edge (for compositional profiles) or by normalizing to some characteristic structure of the near-edge structure (for bonding profiles). The latter is performed typically after subtraction of a smooth power-law background modeled in the region immediately preceding the edge.
- Published
- 1996
- Full Text
- View/download PDF
50. Nitrogen interface engineering in Al[sub 2]O[sub 3] capacitors for improved thermal stability
- Author
-
R. Jammy, J. Bruley, P. D. Kirsch, Dae-Gyu Park, K. K. Chan, and Christopher P. D'Emic
- Subjects
Materials science ,Passivation ,business.industry ,Annealing (metallurgy) ,Electron energy loss spectroscopy ,General Engineering ,Analytical chemistry ,Dielectric ,Chemical vapor deposition ,Capacitance ,Monolayer ,Optoelectronics ,Thermal stability ,business - Abstract
Monolayer (ML) quantities of SiNx have been placed at both top and bottom interfaces of Al2O3 capacitors to improve thermal stability and electrical performance. Bottom SiNx was formed with NH3 anneal. Top SiNx was formed with ultrahigh vacuum chemical vapor deposition (UHVCVD) utilizing SiH4 and NH3. Characterization has been done with current–voltage (I–V), capacitance–voltage (C–V) transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) after 1050°C–30s anneal. I–V measurements show leakage current reduction of 50× with 2 ML UHVCVD SiNx at the polycrystalline-Si∕dielectric interface, while C–V measurements show that capacitance equivalent thickness increases just 1.2A. The leakage current reduction is attributed not only to the increased thickness but also to interface passivation as a result of SiNx deposition. EELS N line profiles show evidence of monolayer quantities of N at both top and bottom interfaces. Good thermal stability beyond the 1050°C-30s anneal for the capaci...
- Published
- 2004
- Full Text
- View/download PDF
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