bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Investigation of the Structural Strains and the Breakdown of Poisson'S Effect in Lattice-Mismatched BCC(110)/FCC(111) Metallic Superlattices
Authors: Fartash A. , Schuller Ivan K. , Grimsditch M. 
Published: March 2011

ABSTRACTThe strain profiles of individual layers of a selected group of stable bcc(110)/fcc(111) metallic superlattices which have been determined by x-ray diffraction methods are compared, and discussed in terms of a number of mechanisms proposed for explaining their anomalous properties. The superlattices in this group are distinguished in terms of a highly anisotropic lattice spacing mismatch of their adjoining bcc and fcc layers (∼20% vs. 3%). The most prominent structural feature of the bcc layers consists of a highly anisotropic in-plane contraction accompanied with a small out-of-plane strain. The fee layers are found to show large out-of-plane expansions which based on their small in-plane expansions cannot be explained within framework of standard elasticity theory.
A Study of Thin Films of Indium Tin Oxide Using Spectroscopic Ellipsometry
Authors: Maloney Colette , Bogdanova Arn N. 
Published: March 2011

ABSTRACTTransparent, electrically conducting, indium tin oxide films were prepared by r.f. reactive sputtering and electron beam evaporation. The refractive indices, n, and extinction coefficients, k, of the films together with their thicknesses were determined from spectroscopic (250nm–750nm) ellipsometry measurements. Elucidation of these parameters allowed an evaluation of the influence of the deposition conditions on the morphology, stoichionietry and microstructure of the films.Using effective medium theory the effect of the oxygen concentration on the void content of the sputtered films could be modelled. At concentrations greater than 15–20%, a saturation in the optical properties was observed as the films approached ideal stoichionietry. The refractive indices of both annealed and untreated evaporated films exhibited a decrease with increasing substrate temperature (up to 300°C) which is consistent with an increase in the microcrystallite size. Measurements on the annealed samples revealed a blue-shift in both n and k spectra as the oxygen pressure during evaporation was reduced to the background value of about 106 mbar. This, we attribute to the Burstein-Moss shift associated with the increased number of oxygen vacancies.Supplementary investigations using profilometry, atomic force microscopy and optical transmission spectroscopy confirm the reliability of the results obtained by this technique.
Microstructure and Defects in Implanted Hipox-Structures
Authors: David Theodore N. , Pegler Peter L. 
Published: March 2011

ABSTRACTHigh-pressure oxidation of silicon (HIPOX) is one of various techniques used for electrical-isolation of semiconductor-devices on silicon substrates. The effect of HIPOX-related stresses on isolation structures is of interest because structural-defects, if formed, could electrically degrade devices. The present investigation was performed to study the origin and behavior of defects in recessed HIPOX structures. The structures were exposed to a boron implant. The experimental observations indicate that glide dislocations arise when the following features are present: (i) HIPOX, (ii) recessed edge, (iii) boron implant. The origin and behavior of the defects are modelled and explained in terms of implant-induced dislocation-sources creating glide-dislocations in the structures. The microstructure of the structures described above, and defect-modelling is presented.
High-Resolution Electron Microscopy of Olivine-Magnetite Interfaces.
Authors: Mckernan Stuart , Barry Carter C. 
Published: March 2011

ABSTRACTIn the oxidation of iron-rich olivine (Mg,Fe)2SiO4 at elevated temperatures interfaces between olivine and the magnetite spinel (Fe3O4) are formed. The orientation relation between these structures is such that the planar spacing for the principal low index planes are very closely matched in the two materials. Regions of different contrast are observed in the olivine up to 5–10 nm from the interface. It is proposed that this contrast is due to enhanced iron concentration in this region caused by the strain field around the magnetite precipitates.
A Study of Extended Defects in Silicon Crystals After Exposure to a Hydrogen Plasma
Authors: Chen Y. L. , Maher D. M. 
Published: March 2011

ABSTRACTThe distribution, number density, and nature of extended defects in crystalline silicon which is exposed to plasma-generated atomic hydrogen at a temperature of 250°C are characterized by transmission electron microscopy. Cross-sectional and plan-view modes are used for these characterizations. Extended defects are typically detected in the near surface region of a < 001 > crystal and their number density may exceed 109 defects-cm2, depending on die plasma exposure time, wafer temperature, gas pressure, and power. These defects exhibit contrast features which are characteristic of small dislocation loops (> 50nm in dia) and the nature of their associated strain field is assessed by diffraction-contrast techniques. The relationship between loop-like contrast features and die so-called hydrogen-induced platelet is established by both diffraction-contrast and phase-contrast imaging techniques. The results show that loop-like and platelet-like images exhibit contrast features which are consistent with a compressive strain field and therefore it is concluded that the extended defects in this study are interstitial in nature.
High Spatial Resolution Tem Study of Thin Film Metal/6H-Sic Interfaces
Authors: Bow J. S. , Porter L. M. , Kim M. J. , Carpenter R. W. , Davis R. F. 
Published: March 2011

ABSTRACTThin films of titanium, platinum, and hafnium were deposited on single crystal n-type, (0001) 6H-SiC at room temperature in UHV. Microstructure and chemistry of their interfaces were analyzed by high spatial resolution TEM imaging and spectroscopy. Ti5Si3and TiC were the two phases found in the reaction zone of Ti/SiC specimens annealed at 700°C. A carbon-containing amorphous layer formed between Pt and SiC when the annealing temperature went up to 750°C. There was no apparent reaction zone in Hf/SiC specimens annealed at 700°C for 60 min‥ The change of electrical properties of metal/6H-SiC devices was attributed to these new product phases.
Formation of Single Crystal Epitaxial β-FeSi2 Films on Si(001)
Authors: Konuma K. , Zagwijn P. M. , Vrijmoeth J. , Vlieg E. , Van Der Veen J. F. 
Published: March 2011

ABSTRACTUltrathin (∼ 1.5 nm) epitaxial films of P-FeSi2were grown by two methods; by sequential deposition of ultrathin amorphous Si and Fe followed by annealing and by mere Fe deposition followed by annealing. During the various stages of the growth process the lattice structure, composition and morphology of the films were investigated by medium-energy ion scattering in conjunction with shadowing and blocking.At RT the deposited Fe reacts with the Si(001) substrate and forms a continuous film of average composition FeSi for both growth methods. Upon annealing to 670 K a conversion into epitaxial β-FeSi2 takes place. β-FeSi2 films grown by mere Fe deposition are composites of two orientational domains. On the other hand, films grown by sequential Si and Fe deposition are essentially of single orientation (>90% A orientation).
Surface and Interface Morphology of Small Islands of TiSi2 and ZrSi2 ON (001) Silicon
Authors: Kropman B. L. , Sukow C. A. , Nemanich R. J. 
Published: March 2011

ABSTRACTThe morphology of small islands of TiSi2 and ZrSi2 on Si(100) is investigated and compared to larger islands in terms of a solid state capillarity model. The silicide islands are formed by deposition of very thin layers of titanium and zirconium (3–50Å) followed by an anneal at high temperatures (700–1200 °C). SEM and cross-sectional HRTEM are used to study respectively the surface and interface morphology. It is found that the C49-phase for TiSi2 is stable for layers as thin as 8Å, and annealing temperatures as high as 1200°C. An explanation for the fact that the formed islands align parallel to the Si<110> directions is given in terms of interplanar lattice spacings.
Effect of the Crystallographic Orientation of Underlying Poly-Si on the Thermal Stability of the TiSi2 Film
Authors: Kim Y. W. , Kim I. K. , Lee N. I. , Ko J. W. , Ahn S. T. , Lee M. Y. , Lee J. G. 
Published: March 2011

ABSTRACTThe effect of the crystallographic orientation of underlying poly-Si film on the thermal stability of the TiSi2 film was studied. Different preferred orientations of the poly-Si film were obtained by annealing poly-Si or amorphous Si films at various temperatures. The TiSi2 film was formed by the solid-state reaction of the Ti film sputtered on the poly-Si film. The thermal stability of the TiSi2 film was evaluated by changes in the sheet resistance and microstructural evolution during furnace anneals. The TiSi2 film on poly-Si with the <110> preferred orientation shows more stable conductivity during high temperature anneals than with the <111> orientation. The surface energy of underlying poly-Si is expected to influence the thermal stability of the TiSi2/poly-Si structure significantly. Better thermal stability of the TiSi2 film can be obtained by the higher surface energy of underlying poly-Si.
Evolution of Epitaxial SixGei1-x Alloys on Si(100) During Thermal Annealing a-Ge/Au Bilayers Deposited on Si Substrate
Authors: Ma Z. , Allen L. H. 
Published: March 2011

ABSTRACTSolid phase epitaxial (SPE) growth of SixGei1-x alloys on Si (100) was achieved by thermal annealing a-Ge/Au bilayers deposited on single crystal Si substrate in the temperature range of 280°C to 310°C. Growth dynamics was investigated using X-ray diffraction, Rutherford backscattering spectrometry, and cross-sectional transmission electron microscopy. Upon annealing, Ge atoms migrate along the grain boundaries of polycrystalline Au and the epitaxial growth initiates at localized triple points between two Au grains and Si substrate, simultaneously incorporating a small amount of Si dissolved in Au. The Au is gradually displaced into the top Ge layer. Individual single crystal SixGei1-x islands then grow laterally as well as vertically. Finally, the islands coalesce to form a uniform layer of epitaxial SixGe1-x alloy on the Si substrate. The amount of Si incorporated in the final epitaxial film was found to be dependent upon the annealing temperature.
Microstructural Characterization of Low Temperature GaAs(111)B MBE Growth by AFM and Tem
Authors: de Boer M. P. , Angelo J. E. , Dabiran A. M. , Cohen P. I. , Gerberich W. W. 
Published: March 2011

ABSTRACTAtomic Force Microscopy (AFM) images are correlated with Transmission Electron Microscopy (TEM) plan-view images in a structure consisting of <111> oriented GaAs layers grown by molecular beam epitaxy (MBE) at 500°C. We present results on the applicability of AFM, which requires short sample preparation and imaging time relative to TEM, in obtaining information on twin density and growth pits of these low temperature samples. Also, we discuss the behavior of twin boundaries by comparing plan-views and cross sectional TEM images.
Stringlike Chemisorption and Rapid Dissociation of As4 and Sb4 on Si(100)
Authors: Gryko J. , Allen R. E. 
Published: March 2011

ABSTRACTDodson-type potentials have been constructed for As-As, Si-As, Sb-Sb, and Si-Sb interactions. The parameters were determined by fitting to the energies obtained in first-principles calculations for As-Si and Sb-Si clusters with a variety of geometries. These potentials have been applied in molecular dynamics simulations of As4 and Sb4 chemisorbing on Si(100) at high temperature (900K). We find that both molecules tend to chemisorb in stringlike configurations, and that dissociation into two dimers can occur within only a few picoseconds.
Effects of Initial Substrate Surface on Microstructure of Si3N4 Deposited by LPCVD
Authors: Lee Woo Y. 
Published: March 2011

ABSTRACTThe morphology of Si3N4 deposited on Al2O3, BN, and SiC by low pressure chemical vapor deposition (LPCVD) was characterized as a function of deposition temperature. At 1200°C, faceted Si3N4 crystallites were deposited on SiC whereas Si3N4 deposited on the other substrates tended to be amorphous. With an increase in temperature to 1430°C, Si3N4 deposited on these substrates was polycrystalline. At this temperature, the microstructure of Si3N4 was not significantly influenced by the changes in substrate surface.
Early Homoepitaxy of Au and pt (100) with Surface-Embedded-Atom Potentials
Authors: Haftel Michael I. , Rosen Mervine 
Published: March 2011

ABSTRACTUsing embedded atom potentials fit to both bulk and surface properties, we explore the submonolayer vapor deposition of Au and Pt onto reconstructed (100) surfaces with the MD code DAMSEL. The surface geometries are determined by computational annealing over .6 ns. Surface reconstruction has a strong influence on the effects of adatoms. In Au and Pt the deposited atoms are absorbed into the surface and surface structures form by atomic replacement sequences and collective motion over the surface and substrate. On Au the reconstructed corrugated surface evolves into one characterized by two-dimensional mounds as coverage is increased. On reconstructed Pt, which exhibits alternately quasihexagonal and bulk-like regions, adatoms initially form strings above the bulk-like regions parallel to the (110] corrugation rows. At about .5 monolayer coverage the quasihexagonal structure of the top substrate layer transitions to a bulk-like structure in both Au and Pt
The Influence of Diamond Surface Perfection on the Preferential Nucleation of SP2 Carbon During Methane Pyrolysis
Authors: Lin B. Y. , Beetz C. P. , Brown D. W. , Lincoln B. A. 
Published: March 2011

ABSTRACTWe report a set of CH4 pyrolysis experiments in a UHV system on diamond surfaces having varying degrees of surface roughness or perfection. Scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and reflection high energy electron diffraction (RHEED) were used to examine the formation of graphite and the resulting surface morphologies. A (100) type Ha natural diamond having 3 sputtered craters on the surface was used as the substrate, sp2 carbon was formed preferentially on the structurally defective crater surfaces after ∼3×1010 L of CH4 exposure at 900°C, whereas essentially no sp2 carbon was found on the flat portions of the diamond surface. Similar experiments were also carried out on a polycrystalline CVD diamond film and sp2 carbon was formed on that surface afte ∼4×109 L of CH4 exposure at 900°C. These results indicate that structural defects on diamond surfaces are a crucial factor in the preferential nucleation of sp2 carbon during CH4 pyrolysis.
AFM Study of Nucleation and Void Formation in SiC Carbonization of Si
Authors: Li J. P. , Steckl A. J. 
Published: March 2011

ABSTRACTIn this paper the nucleation mechanisms for SiC thin film growth are studied by rapid thermal CVD and atomic force microscopy (AFM). The nucleation mode was found to be strongly dependent on the hydrocarbon partial pressure in the gas stream, for a fixed reaction time. In the case of three-dimensional (island) growth at low precursor concentration, cross-sectional SEM micrographs indicate that no voids are present at the center of each nucleus (or island). Voids begin to form when two neighboring nuclei come in contact. AFM has shown that trenches are present in the Si substrate around each isolated nucleus. The trench depth increases with the diameter of the island. AFM analysis of films grown for a nominal reaction time of 1 sec at different propane concentrations indicates that: (1) SiC grain size and surface roughness decreases with increasing propane concentration; (2) SiC grain density increases with increasing propane concentration. Based on the above evidence, the following nucleation mechanism is proposed: (a) the initial nucleation density is determined by the precursor concentration in the reaction gas; b) each nucleus grows larger, both laterally and vertically, by consuming Si around it; (c) voids are formed when nuclei grow large enough to come in contact, and not at the original nucleation sites.
Electrochemical Sulfur Treatments of GaAs Using Na2S and (NH4)2S Solutions: A Surface Chemical Study
Authors: Yota J. , Burrows V. A. 
Published: March 2011

ABSTRACTChemical sulfur treatments of GaAs have been shown to improve the GaAs surface electronic properties. These treatments result in lower surface state density, lower surface recombination velocity, and shifting or unpinning of the Fermi level, in addition to improvement in the performance of devices. However, there is still considerable controversy regarding the chemical nature of the surface film which results from this chemical sulfidation. It has been shown that this film is not stable chemically and electronically. The improved surface electronic properties decay with time and are sensitive to the chemical environment of the material. In this study, using surface infrared reflection spectroscopy (SIRS) and x-ray photoelectron spectroscopy (XPS), we have investigated the electrochemical sulfidation of GaAs as a possible new method to produce a GaAs surface that is stable chemically and electronically. We have found that anodic treatments with Na2S and (NH4S solutions result in the removal of the pre-existing oxide of GaAs and the formation of films comprising sulfur, sodium carbonate, ammonium thiosulfate, and sulfide and sulfur-oxygen compounds of arsenic. Rinsing the GaAs with water removes the bulk of the film, leaving behind a surface on which only arsenic sulfide was detected.
Surface Chemistry of GaAs(100) after Treatment with Aqueous H3PO4 Solution
Authors: Burrows V. A. , Kondapuram V. S. G. 
Published: March 2011

ABSTRACTThe interaction of semiconductor surfaces with aqueous acid solutions is important in chemical cleaning and etching. Wet chemical treatments are advantageous because they cause little damage to the surface and do not usually require high temperatures. The surface chemistry of GaAs after treatment with phosphoric acid was studied using multiple internal reflection infrared spectroscopy. The treatment left behind a thin film containing several types of PxOy bonds. The chemical nature of the film was observed to change with time as new species would form on the surface.
Repair of Flat Panel Display Substrates by Laser Direct Writing of Metallic Platinum, Copper and Aluminum and Insulating Aluminum Oxide Utilizing Gas Phase Reactants
Authors: David Casey J. , Comunale Richard A. 
Published: March 2011

ABSTRACTThe identification and repair of defects in flat panel displays (FPD's), most especially liquid crystal, are required to achieve acceptable manufacturing yields and reasonable costs. Laser cutting and laser direct writing, from gas phase reactants, are used to repair opens and shorts in conductor lines of FPD substrates (the LI laser repair system). This paper details platinum, copper and aluminum deposition processes including deposition parameters, conductivity data, Auger evaluations and microscopy characterizations. Life-study data on repaired, fully assembled FPD's will be presented. Also the laser direct-writing process for aluminum oxide, used to repair dielectric defects and to passivate metal repairs, will be described. Finally, a unique, localized vacuum system (SPOT VAC™ ), specifically engineered for laser deposition on large (500 × 500mm) flat substrates, will be detailed.
CBE Growth Characterization of GaAs and InGaAs by Rheed and RD
Authors: Paulsson G. , Junno B. , Samuelson L. 
Published: March 2011

ABSTRACTTriethylgallium, trimethylindium and tertiarybutylarsine have been used to grow GaAs and InGaAs on (OO1)GaAs. No pre-cracking was used so that the thermal decomposition of tertiarybutylarsine on GaAs could be studied. The growth has been monitored in-situ using reflection high-energy electron diffraction and reflectance-difference. A comparison ismade between the reflectance difference signal and the intensity of the reflection high-energy electron diffraction specular spot as the surface is transformed from As rich to Garich. Using the former technique similar growth transients have also been studied as a function of the temperature. It is found that the incorporation of small amounts of In (less than 5 per cent) in the buffer layer significantly improves the oscillatory behavior of the RD-signal when growth of GaAs is commenced. Finally, the growth dynamics of InGaAs isstudied using reflection high-energy electron diffraction.
Comparison of GaAs Metallization Systems for High Temperature Applications
Authors: Scofield J. , Liu S. , Smith S. 
Published: March 2011

ABSTRACTTransition metal-germanide/silicide based ohmic contact systems to n-type GaAs have been studied using current-voltage (I-V) and transmission line measurements (TLM). The effects of substituting various metals from groups IVB and VIB into the metallization stack have been compared, as well as the effects of using germanium or silicon. Rapid Thermal Annealing (RTA) was used to facilitate the reactions. Titanium and molybdenum were shown to be more effective metallizations than chromium, even though chromium readily forms a silicide or germanide. Germanium has been found to produce an ohmic contact of low resistivity, while metallization with silicon alone does not show ohmic behavior.
Surface Investigations of Germanium Chemical Vapor Deposition on Silicon
Authors: Greenlief C. Michael , Klug Debra-Ann , Du Wei , Keeling Lori A. 
Published: March 2011

ABSTRACTThe adsorption and decomposition of several Ge-containing compounds on Si(100) have been investigated with the intent of elucidating the surface processes leading to the deposition of epitaxial Ge films from these gaseous sources. Exposure of digermane, Ge2H6/ to Si(100) at 110 K results in molecular adsorption and ab initio calculations are used to help interpret the low temperature ultraviolet photoelectron spectrum. Diethylgermane, GeH2Et2, chemisorbs dissociatively on Si(100) at 110 K. The adsorption products are GeH2 and adsorbed ethyl groups. Large exposures of GeH2Et2 result in the formation of a physisorbed layer of molecular GeH2Et2 on top of the dissociated layer. The surface ethyl groups thermally decompose near 670 K via a β-hydride elimination reaction evolving C2H4 into the gas phase. The interactions of Ge2H6 and GeH2Et2 with Si(100) are discussed and compared to similar experiments with GeH4 as the Ge-containing gas source.
Investigation of the Kinetics of Surface-Limited thin Film Growth of SiGe Alloys by CVD of Si2H6/Ge2 H6 Mixtures
Authors: Sharp J. W. , Eres Gyula 
Published: March 2011

ABSTRACTThe kinetics of surface-limited thin film growth of SiGe alloys was investigated by time-resolved surface differential reflectometry. The source gas, mixtures of disilane and digermane in ratios from 1:1 to 6:1 in helium carrier gas, was delivered to a heated Si(001) substrate by a fast-acting pulsed molecular jet valve. The adsorption and desorption kinetics were determined from the surface differential reflectance signal obtained using a polarized, high-stability HeNe probe laser. Thin film growth was studied in the temperature range of 400–600°C on Si(001) substrates. Preferential incorporation of digermane into the film produces an alloy composition that depends upon but does not mirror the gas composition. For all gas mixtures, there is a strong temperature dependence of the rate at which the adsorption layer decomposes into film plus by-product. The kinetic data and the alloy compositions provide a basis for deducing some of the characteristics of the reaction sequence that leads to SiGe alloy thin film growth.