bluuebunny/crossref_metadata_2025_split huggingface dataset:
On Devitrification of Monticellite (CaMgSiO4) Films Grown on (001)-Oriented Single-Crystal MgO.
Authors: Yanina Svetlana V , Johnson Matthew T , Mao Zhigang , Carter C Barry 
Published: July 2020

Abstract
Silicate glasses are the most common constituents of intergranular phases which can be found in liquid-phase sintered ceramics [1]. Silicates are known to influence the structure of ceramic interfaces which, in turn, frequently affect mechanical properties of ceramic materials [2]. In earlier studies of silicate glasses on single-crystal alumina Ramamurthy et al [3] and Mallamaci [4] showed that the morphology of dewetted glass films and the mechanism of devitrification depend on the crystallographic orientation of the substrate surface. In continuation of these studies, results are presented on the dewetting behavior of monticellite (CaMgSi04) in contact with the (OOl)-oriented surface of single-crystal MgO. Due to the simplicity of sample preparation and availability of 3- dimensional topographic information, Atomic Force Microscopy (AFM) was used for surface characterization. These AFM results are complemented by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) data on the chemical composition and the structure of the glass-substrate interface.
Defects in Pseudo-Orthorhombic Anorthite on Basal Sapphire
Authors: Mao Zhigang , Johnson Matthew T , Carter C Barry 
Published: July 2020

Abstract
Crystallization of intergranular glass films can influence the performance of ceramic materials [1]. The crystallization of anorthite glass films has been studied in situ in the transmission electron microscope (TEM) [2]. The films are grown by pulsed-laser deposition (PLD) on sapphire (α-AI2O3) substrates. These substrates can be pre-thinned to electron transparency, so that contamination or microstructural damage of the TEM specimen due to the thinning process can be eliminated. This process also allows the microstructure of the glass films to be characterized before crystallization; the evolution of specific features of the film can then be tracked through repeated heat treatments. Prior to the crystallization of the anorthite glass films, observations confirmed that all the glass films deposited by PLD are indeed amorphous. Crystallization experiments were performed in a Philips CM30 TEM equipped with a Gatan single-tilt heating holder. Each specimen was heated in the microscope to a temperature of about 1200 °C at a heating rate of about 30 °C/min. and held at this temperature for 20 minutes.
The Effect of an Electric Field on the Reaction Between Oxides
Authors: Johnson Matthew T , Carter C Barry 
Published: July 2020

Abstract
It is well known that diffusion in ionic materials occurs primarily by the movement of charged species. Therefore, an applied electric field can provide a very large driving force for mass transport. In the present study, thin films of In2O3 and Fe2O3 have been deposited on (001) and (111) MgO using pulsed-laser deposition (PLD). These thin-film diffusion couples have then been reacted in an applied electric field at elevated temperatures. The electric field directly influences the diffusion of the cations in the constitutive layers. Through the use of both transmission (TEM) and scanning (SEM) electron microscopy, diffusion couples reacted either with and without an electric field have been analyzed to examine the effect that an induced ionic current can have on solid-state reaction processes.
The apparatus for reacting the diffusion couples in a field has been described elsewhere. The diffusion couples were characterized in cross-section by SEM and TEM techniques.
Image Periodicities Introduced by Three-Fold Astigmatism in HRTEM Images of α-Al2O3 and Related Materials
Authors: Medlin DL , Smugeresky JE , Cohen D 
Published: July 2020

Abstract
HRTEM images of α-Al2O3 oriented along [1100] often exhibit a modulation of the basal fringe intensity with a period that corresponds to twice the basal plane spacing. In the example shown in figure 1, note the strong basal fringe contrast in the A12O3 with a period of 4.33 Å. HRTEM image simulations for ideal imaging conditions fail to reproduce this doubling of the lattice fringe period. Instead, simulated images predict that the (0006) fringes (d0006=2.17 Å) should be of equal intensity (e.g., see Figure 3a). Incorrect beam and/or crystal tilt can strongly affect HRTEM image contrast. In particular, anomalous periodicities can arise under beam and crystal tilt conditions for which normally kinematically and dynamically forbidden diffracted beams contribute to the image. More recently, the importance of 3-fold astigmatism on HRTEM imaging has been recognized. As with beam tilt, this lens aberration produces asymmetrical phase shifts in the diffracted beams.
Heterogeneous Oxidation and Precipitation of Aqueous Mn(II) at the Goethite Surface: A SPM Study
Authors: Rakovan John , Hochella Michael F 
Published: July 2020

Abstract
Since its invention inl982 scanning probe microscopy (SPM) has become an important analytical tool in every branch of physical science. The two most widely used types of SPM are atomic force Microscopy (AFM) and scanning tunneling microscopy (STM). Both AFM and STM allow measurement of the microtopography of a surface down to the atomic scale. Many spin-off applications such as lateral force and magnetic force allow measurement of a variety of the physical properties of a surface while imaging its microtopography. SPM can be done in both air and liquid and hence can be used to observe the interactions that take place at a solid-solution interface.
SPM has been used in mineralogy and geochemistry since 1989. Here as in other applications the great strength of SPM is in the characterization of the heterogeneous nature of mineral surfaces and the ability to observe many geochemical processes in real time.
Microstructures and Microanalysis in ALH84001: Minerals or Martians?
Authors: Harvey Ralph P , Bradley John , McSween Harry Y 
Published: July 2020

Abstract
The martian meteorite ALH84001 leapt into the spotlight in late 1996 when a NASA-led research team suggested that it contained evidence of biotic activity on ancient Mars. ALH84001 is unique among the martian meteorites- a cumulate rock made up predominantly of orthopyroxene, with interstitial maskelynite (feldspar turned into a diaplectic glass by shock), apatite, chromite and sulfides. Highly brecciated fracture zones cut through the rock, presumably a result of impacts, and within these zones is a variable amount of secondary carbonate. This carbonate, the most extensive secondary mineral found in any martian meteorite, formed during significant interaction between martian crust and volatiles, and represents a unique access point toward understanding the environment of ancient Mars. However, the conditions under which this carbonate formed are less clear. While claims for evidence of biotic activity are predicated on carbonate formation at low (&lt;100°C) temperatures under water-rich conditions, other research suggests much less hospitable conditions, with little water present and formation temperatures approaching 700°C.
Local Strain Measurements in Hexagonal Systems
Authors: Kisielowski Christian , Schmidt Olaf 
Published: July 2020

Abstract
It is challenging to access the microscopic distribution of strain in subsurface systems with a lateral resolution better than 1 nm and an accuracy of about 10-3 because such measurements require the detection of displacements by 1 pm at near atomic resolution. Nevertheless, such measurements are commonly desirable, in particular, for the investigations of thin heteroepitaxial films. A particular method developed in the past extracted geometrical information from unit cells in lattice images to perform this task in thin layers of cubic quantum well structures. Strain relaxation in thin TEM samples may falsify such measurements and needs to be controlled. It is the purpose of this paper to describe a quantitative method to measure strain with the required accuracy and resolution in the more complex hexagonal systems. A AxGa1-xN/GaN heterostructure grown on a sapphire substrate was investigated. Local strain comes from compositional variations which alter the size of the unit cells that are shown in Figure 1.
The Determination of Copper Composition Profiles in Semiconductor Device Aluminum Interconnect Electromigration Test Lines using Electron Probe Microanalysis (EPMA)
Authors: Oparowski JM , Sriram TS , Ambrose V 
Published: July 2020

Abstract
Extensive long range transport of copper has been observed in polycrystalline aluminum-copper (Al-Cu) interconnects subjected to accelerated electromigration testing. Cu depletion is believed to be the rate limiting factor for electromigration damage accumulation. It is not clear if this is also the case for Al-Cu interconnects with bamboo/near-bamboo microstructures. In order to understand this phenomenon, Cu transport under electromigration conditions in bamboo microstructures has to be characterized quantitatively. This paper describes the procedure used to determine Cu distributions on a series of bamboo test structures subjected to accelerated electromigration (EM) testing. Copper composition profiles were determined for these structures through the use of electron probe microanalysis (EPMA) techniques and customized corrections for non-standard interaction volumes.
Aluminum (0.5 wt.% Cu) interconnect test line structures were fabricated with four metal layers and surrounding silicon dioxide dielectric. Following EM testing, the samples were deprocessed to expose the test lines at metal layer three, as shown in Figure 1.
Hrtem Study of Interface Structure Of Heteroepitaxially Grown GaAs Thin Films on GaAs(l00)
Authors: Dai ZR , Chegwidden SR , Ohuchi FS 
Published: July 2020

Abstract
GaSe, a member of the III-VI compound semiconductors, and its related compounds have recently gained an considerable attention because of their high non-linear optical coefficients in the infrared ranges, making them candidates for second harmonic generation (SHG) materials[l,2]. While the optical properties of those materials in bulk form are quite promising, poor thermal and mechanical properties preclude their easy applications. In thin film devices, the thermal and mechanical properties are dominated by those of the substrate, therefore, heteroepitaxially grown thin films of GaSe and related materials on substrates such as GaAs, Si and A12O3 should enable their application in device structures. Development of such new generation of materials, however, require fundamental knowledge about the surface and interface structure that play decisive roles in the thin film crystallinity and materials properties.
Microstructure of Porous Silicon Thin Films
Authors: Berta Y , A. Gerhardt R 
Published: July 2020

Abstract
Porous silicon has potential applications in the microelectronics industry. It has been investigated as an electroluminescent source1, as a sensing device in chemical sensors and as an antireflective coating for solar cells. The low efficiency of the solar cells is enhanced by the antireflective coating that porous silicon provides, while the cost of fabrication of the cells is decreased. Porous silicon is normally processed by electrochemical anodization of silicon wafers. Since parameters such as current density, anodization time, and surface conditions can affect the microstructure of the films obtained, we varied the current density to study the effect of the microstructure on the resultant reflectance for the purpose of improving it. It has been found that higher current densities result in higher reflectance films than the lower current densities.
Solid-Phase Epitaxial Regrowth of GaAs by in-situ Controlled Intermediate Phase Decomposition
Authors: Farrer JK , Caldwell DA , Palmstrom CJ , Carter CB 
Published: July 2020

Abstract
A transmission electron microscopy (TEM) analysis on the regrowth of GaAs by a two-stage reaction between a metal layer (M) and a GaAs substrate is presented. The first stage of the regrowth process is the consumption of GaAs in a low temperature reaction with the metal layer, producing an intermediate phase of (MxGaAs). A second solid-phase reaction, induced by the deposition of Ga or As, results in the decomposition of the intermediate phase and the epitaxial regrowth of a layer of GaAs. The sample growth and reactions were performed in-situ in a molecular beam epitaxy system, using Ni for the metal and As deposition for the second reaction. TEM data confirm the formation of the ternary phase, NixGaAs, and its subsequent decomposition into NiAs and GaAs by reacting with the deposited As. A layer of AlGaAs, 100 nm thick, was grown in all samples as a marker.
Scanning Capacitance Microscopy of Dopants in III-V Semiconductors
Authors: Lang David V 
Published: July 2020

Abstract
Scanning Capacitance Microscopy (SCM) was first developed in 1985 as a method for sensing tip-to-sample spacing for surface topography profiling in connection with the RCA VideoDisc. Williams and coworkers were the first to use an SCM for obtaining dC/dV doping profiles in semiconductors, albeit with a rather modest resolution of 200 nm. More recently, it has been developed as a 50-nmresolution tool for microscopic doping analysis of semiconductors by measuring the tip-to-sample rf capacitance in an AFM controlled by other means, e.g. by laser beam deflection of a cantilever tip. In this paper we report on the application of SCM to study the 2D doping profiles of InP-based devices, such as multi-quantum well lasers.
It is particularly convenient to prepare cross sections of III-V devices, since the material readily cleaves on [110] planes, as compared to silicon where cross sections must be obtained by painstaking polishing.
Electron Holography of Semiconductor Junctions
Authors: McCartney M R , Li Jing 
Published: July 2020

Abstract
TEM has not traditionally contributed to characterization of semiconductor junctions, except for some intriguing results by Perovic, Hull and Alvis where highly doped layers gave contrast under very specific sample preparation and imaging conditions. Since electron holography is sensitive to the phase of the electron wavefront that has passed through the sample, it has the potential to provide voltage contrast. In principle, given its inherent two-dimensional and quantitative character, electron holography is a strong candidate for analysis of semiconductor device junctions.
The sample for the work reported here was one of a group of test specimens fabricated at IBM for a dopant metrology round-robin comparison to evaluate various profiling methods. The substrate was &lt;100&gt; p-type silicon, boron-doped at 11-25 Ω-cm-1. The test structure was fabricated using low- temperature epitaxial growth and consisted of an abrupt p-n junction, formed by abutting 1020cm-3 doped regions of boron and phosphorus
Scanning Electron Microscopy of Dopants in Semiconductors
Authors: Venables D 
Published: July 2020

Abstract
It has been demonstrated that doped regions in semiconductors yield contrast in secondary electron images taken under appropriate imaging conditions. Perovic et al. attributed this "electronic" contrast to surface potentials arising from the bending of the energy bands at the surface of the semiconductor. This band-bending results from the presence of surface states which pin the Fermi level. These effects have found application to an important problem in the electronics industry -- the profiling of dopant distributions in two-dimensions. However, such dopant distributions are rarely uniform, i.e., the dopant concentration may change over many orders of magnitude within distances of only a few tens to hundreds of nanometers. Therefore, it is necessary to understand how the observed contrast from the doped regions varies for non-uniform dopant distributions to apply the technique to real electronic devices.
Microscale Elemental Imaging of Semiconductor Materials Using Focused Ion Beam Sims
Authors: Stevie F A , Downey S W , Brown S , Shofner T , Decker M , Dingle T , Christman L 
Published: July 2020

Abstract
The semiconductor industry demands elemental information from ever smaller regions. Two types of information in demand are two dimensional dopant profiles for the MOS transisitor and identification of particles as small as 30 nm diameter. The work of Levi-Setti and others resulted in liquid metal ion source (LMIS) instruments that provided secondary ion mass spectrometry (SIMS) images using Ga+ beams with 20 nm lateral resolution. It is now possible to purchase focused ion beam (FIB) systems with 5 nm beam capability and SIMS detection.
The application of LMIS SIMS to meet semiconductor demands has been pursued in our laboratory with a FEI-800 FIB. SIMS imaging of semiconductor patterns after etch has shown the ability to identify boron and carbon contamination. Figure 1 shows boron in a comb structure after a BC13 etch. The boron can be shown to be removed by a cleaning step.
Direct Imaging of Device Characteristics In a Focused ion Beam System
Authors: Campbell A N , Soden J M 
Published: July 2020

Abstract
A great deal can be learned about integrated circuits (ICs) and microelectronic structures simply by imaging them in a focused ion beam (FIB) system. FIB systems have evolved during the past decade from something of a curiosity to absolutely essential tools for microelectronics design verification and failure analysis. FIB system capabilities include localized material removal, localized deposition of conductors and insulators, and imaging. A major commercial driver for FIB systems is their usefulness in the design debugging cycle by (1) rewiring ICs quickly to test design changes and (2) making connection to deep conductors to facilitate electrical probing of complex ICs. FIB milling is also used for making precision cross sections and for TEM sample preparation of microelectronic structures for failure analysis and yield enhancement applications.
Templating Effects On C54-Tisi2 Formation In Ternary Reactions.
Authors: Quintero A , Libera M , Cabral C , Lavoie C , M. Harper J 
Published: July 2020

Abstract
Titanium disilicide (C54-TiSi2) is a low resistivity silicide (15 - 20 μΩ-cm) and is widely used in the device industry. It is formed at about 750-850 °C when thin layers (∽30- lOOnm) of Ti on poly- or single-crystal Si substrates are subjected to rapid thermal annealing (3 °C/sec) in a controlled atmosphere (N2). During the anneal, other Ti silicides such as Ti5Si3, Ti5Si4,TiSi and C49-TiSi2 may form prior to the desirable C54-TiSi2.
Some attempts have been made to promote low-temperature C54-TiSi2 formation. Depositing a Mo (l-2nm) interlayer between Ti and Si has been reported to decrease the C54 formation temperature by 100 °C.2 Codepositing Ti with Ta, Nb or Mo has successfully decreased the formation temperature by about 150 °C.3 These findings have been interpreted in terms of a template mechanism which facilitates formation of C54 by advantageous lattice matching between similar planes in C54 and a hexagonal ternary (Ti- X-Si, X=Ta, Nb, Mo) C40 precursor phase.
Crystallographical Analysis of Intermediate Phases in BI(2223)/AG Tape
Authors: Wu Lijun , Zhu Yimei , Suenaga M 
Published: July 2020

Abstract
(Bi,Pb)2Sr2Ca2Cu3Ox/Ag composite tapes are currently the most promising high-temperature superconductors for large-scale applications. A major issue in further improving the supercurrent-carrying-capability and optimizing fabrication procedures of these tapes is to understand the formation kinetics of the Bi(2223) from precursor powders of Bi(2212), CaO, and CuO. Since the microstructural transformation during the complicated phase evolution is not well known yet, identification of minor phases at different transformation stage is desirable. Here, we report our crystallographic analysis of several frequently observed intermediate phases during the phase evolution.
The heat treatment of the tapes consisted of ramping the temperature to 840°C in air and of holding it for a prescribed period and then oil-quenching from various temperatures.
Oxide Structures: By Hook Or by Crook
Authors: Marks L D , Sinkler W , Zhang H 
Published: July 2020

Abstract
Sometimes oxides are friendly; x-ray or neutron diffraction solves the structure and (at most) simple HREM does a double check. Sometimes they are not. Problems can range from phase purity (identifiable using EDX) to more subtle issues about the true unit cell and/or atom locations. The latter are often particularaly hard for x-ray or neutron to handle when single crystal data is not available and, for instance, the samples are polyphase or textured.
One common problem is that the unit cell is rather larger than originally thought due to a superstructure. While superstructure reflections may be obvious in the microscope due to the very large dynamic range of TED patterns, they may not show in powder patterns. The issue then is to determine the true structure using (often) a combination of HREM and TED plus multislice simulations to confirm the structure.
Study of the Hole Distribution in Oxide Superconductors Using a Sensitive Electron Diffraction Technique
Authors: Tafto J , Wu Lijun , Zhu Yimei 
Published: July 2020

Abstract
A key towards understanding the properties of high-temperature superconductors is knowledge about the distribution of the valence electrons and holes. Despite their complicated crystal structure, electronic structure of many cuprates has been calculated. The most successful calculation method is based on the theorem that the ground state energy is a unique functional of the electron density. Thus, experimental techniques that give information about the valence electron density are essential to test the calculations and to gain further insight into these important materials.
To move beyond locating the atoms in the crystal unit cell towards addressing the details of the electron distribution requires in general extremely accurate diffraction experiments. Highly perfect crystals with small unit cells have been approached. It has been known for several decades that in electron diffraction the amplitudes of those reflections at small scattering angles that are present in crystals with large unit cells, are strongly influenced by the valence electron distribution.
The Electronic Structure and Bonding of Copper Oxides by CBED and EELS
Authors: Kim M Y , Alvarez J , Zuo J M , Spence J C H 
Published: July 2020

Abstract
Cu2O and CuO are of great interest after the discovery of the high Tc superconductors. The superconductivity is believed to be dependent on charge states in CuO2 layers whose structure is similar to that of CuO. These transition-metal compounds are also important because of the different copper coordination numbers and different copper-oxygen distances, therefore these reflect different electron density distributions and bonding mechanisms. The electronic structure of cuprite has been studied extensively both theoretically and experimentally because of its symmetrical crystallographic structure (space group ) while that of CuO (space group C2/c) which has a monoclinic structure has been studied only recently. Previous experimental and theoretical results show that the valence electrons of copper in cuprite form hybrid states which is proposed by Orgel instead of spherical d10 state as in ionic copper.