bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reaction Kinetics of Atomic chlorine on Si(100)2×1
Authors: Karahashi Kazuhiro , Matsuo Jiro , Horiuchi Kei 
Published: March 2011

ABSTRACTThe interaction of atomic chlorine with Si(100)2×1 surfaces was studied by using chlorine atom beams. The etching reaction of silicon substrates has been observed when chlorine atoms impinged on the chlorinated surface, at substrate temperatures below 600°C. The major desorption product is SiCl2. Studies of the temperature dependence of the reaction showed that the activation energy are 0.08 eV at 0.4 ML and 0.2 eV at 0.8 ML. These extremely low activation energies suggest that the surface reaction is mainly driven by the internal energy of incident atomic chlorine instead of thermal excitation from Si(100) solid surface. Therefore chlorine atoms enter the transition state without equilibrating at the surface prior to the reaction. The reaction strongly depends on the chlorine coverage on the surface. The reaction occurred above 0.3 ML. The etching probability of the surface reached a maximum at 0.4 ML, and decreased with increasing coverage.
Interface Roughness: What is it and How is it Measured?
Authors: Chason E. , Falco Charles M. , Ourmazd A. , Schubert E. F. , Slaughter J. M. , Williams R. S. 
Published: March 2011

ABSTRACTA panel discussion on interface roughness was held at the Fall 1992 Materials Research Society meeting. We present a summary of the results presented by the invited speakers on the application and interpretation of X-ray reflectivity, atomic force microscopy (AFM), scanning tunneling microscopy (STM), photoluminescence and transmission electron microscopy. A transcript of the moderated discussion is provided in the final section.
Interface Roughness Determined by Diffuse Scattering and by Reflectivity of Hard X-Rays
Authors: Lengeler B. , Hüppauff M. 
Published: March 2011

ABSTRACTX-ray reflectivity and diffuse scattering are powerful techniques for the non-destructive determination of the vertical and lateral roughness of external and internal interfaces. The influence of roughness on the reflected and transmitted amplitudes is treated in terms of a model first described by Névot and Croce. The diffuse scattering is described by an improved distorted wave Born approximation. A few examples will demonstrate the possibilities of the techniques.
Investigation of Roughness at InP/InAs Interfaces
Authors: Brasil M.J.S.P. , Nahory R. E. , Tamargo M. C. , Schwarz S. 
Published: March 2011

ABSTRACTWe have investigated the interface roughness of single thin InP/InAs quantum wells grown by Chemical Beam Epitaxy. We report results of low temperature photoluminescence and secondary ion mass spectroscopy. The interface roughness is characterized by multiple-line photoluminescence spectra and is very sensitive to parameters such as the growth temperature. Details of the interface roughness are discussed based on the shifts of the excitonic energies observed by photoluminescence.
A New Quantitative Roughness Measurement and its Application in the Polysilicon/Silicon Dioxide Interface
Authors: Lin Su-Heng , Hatalis Miltiadis K. 
Published: March 2011

ABSTRACTA quantitative approach for characterizing the interface roughness between two materials by cross sectional transmission electron microscopy (XTEM) is proposed. This approach is based on obtaining an interface height distribution curve (IHDC). The interface roughness can be characterized quantitatively by extracting from IHDC three parameters: the mean, median and maximum interface height. This new method has been applied in the characterization of the interface between thermally grown silicon dioxide and polycrystalline silicon thin films deposited by low pressure chemical vapor deposition. It is shown that high temperature processing yields an interface that has higher roughness.
Surface Roughness in Kinetic Growth with Diffusion
Authors: Yan Hong 
Published: March 2011

ABSTRACTThe evolution of surface roughness in kinetic growth with diffusion is studied by computer simulation of ballistic deposition with an activated hopping algorithm, in which the deposited particles diffuse on the surface via random walks. The results demonstrate that the KPZ-type scaling dictates the asympototic statistical properties of surface roughness at elevated temperatures, which are consistent with earlier studies. As surface diffusion is crucially dependent on substrate temperature and deposition rate, we show that they play essential roles in determining the morphology of the film.
The Origins of Epitaxial Orientations in thin Films
Authors: Thompson Carl V. 
Published: March 2011

ABSTRACTWhen a continuous film is deposited on a planar, single crystal substrate, there is usually a single set of relative film-substrate orientations for which the free energy of the film-substrate interface is minimized. It is often assumed that epitaxial films have adopted the orientation which minimizes this energy. However, this is not necessarily the case. Orientation selection is also constrained by minimization of the energy of the/reesurfaceof a film, as well as by minimization of the strain energy. In systems in which films grow by an island mechanism, epitaxial orientations can be established duringor afternucleation, and can change before orafterformation of a continuous film. Interfacial and surface energy minimization is constrained differently for islands and films. Epitaxial grain growth is a process which occurs in continuous films, in which epitaxially-aligned, energy-minimizing grains grow at the expense of other grains. Recent experiments on epitaxial grain growth in polycrystalline Ag films on single crystal Ni is discussed to illustrate, the affects of surface, interface, and strain energy minimization on epitaxial orientation selection.
Role of Atomic Size and Valence in Bonding and Diffusion at Metal Surfaces
Authors: Feibelman Peter J. 
Published: March 2011

ABSTRACTFirst-principles calculations and corresponding experimental results underline the importance of basic chemical concepts in understanding bonding and diffusion of atoms at and on metal surfaces. Examples discussed include the outward relaxation of clean Be(0001), the separation energies of metal-adatom dimers, concerted substitutional self-diffusion on fcc(001) and (110) surfaces, and adsorption and diffusion barrier sites for adatoms near steps.
Substrate Surface Structure Effects on Microstructure of Epitaxial Films
Authors: Guo J. , Chang H.L.M. , Zhang H. , Lam D. J. 
Published: March 2011

ABSTRACTThe microstructure of epitaxial thin films grown on sapphire substrates using the metal organic chemical vapor deposition (MOCVD) technique were found to depend on the substrates surface structure. The epitaxial Ti02 films grown on the sapphire (0001) substrates were highly-oriented poly-crystal and the films on the (1120) substrates were single crystal. First-principles total energy calculations were carried out to gain atomistic understandings of sapphire surface structures and their effects on microstructure of epitaxial films. The surface terminating atom planes were found to be Al atoms for the (0001) surface and O atoms for the (1120). The minimum step heights were found to be one sixth of the lattice constant c for the (0001) and one half of the lattice constant α for the (1120). The steps of the minimum height or its odd multiples on sapphire (0001) surface were shown to double the number of variants in the deposited films. The symmetry and step of the substrate surface and the symmetry of the epitaxial growth plane were found to control the microstructure of the epitaxial films.
Lattice Orientations of Evaporated Metals onto Uniaxially Oriented, Semicrystalline, Ultra thin Polymer Films
Authors: Jandt Klaus D. , Buhk Maren , Petermann Jürgen , Eng Lukas M. , Fuchs Harald 
Published: March 2011

ABSTRACTThe textured oriented overgrowth (epitaxy) of certain metals evaporated onto substrates consisting of highly oriented ultra thin polymer films of polyethylene (PE), polypropylene (PP) and polybutene-1 (PB-1) has been well known since a few years. However, the origin of the observed epitaxy is not clear at all: graphoepitaxy (i. e. orientation induced by nucleation onto oriented topographic features of the substrate), the formation of a chemical layer (i. e. of metal-methyl groups building up the polymer-metal interface, or simply classic epitaxy (i.e. lattice matching) seem all to be possible explanations for the observed orientations. Here, we used Transmission Electron Microscopy (TEM) and Scanning Force Microscopy (SFM) to investigate the possibility of graphoepitaxial growth on polymeric surfaces. Our investigations show that the morphology of polymeric bulk material determine the topographic properties observed at the polymer surface. The semicrystalline nature of the polymer films leads to polymeric surface steps which are suitable as locations for graphoepitaxial growth. Artificial epitaxy (graphoepitaxy) seems to be the most likely orientation mechanism.
Mass Flow and Stability of Nanoscale Features on AU(111)
Authors: Cooper B. H. , Peale D. R. , Mclean J. G. , Phillips R. , Chason E. 
Published: March 2011

ABSTRACTWe present the use of an STM to make quantitative observations of time-dependent mass flow associated with the decay of two-dimensional clusters on the Au(111) surface. When formed and observed in air, layered islands with well-defined edges located on larger terraces are generally found to decay in such a way that their areas decrease linearly in time over periods ranging from minutes to several hours depending on the island size. This is in contrast to the behavior of similar features formed and observed under ultra high vacuum conditions, which do not appear to decay over experimental periods of several days. The linear decay is consistent with models that have been used previously to describe growth of 2-dimensional clusters on surfaces. We discuss possible decay mechanisms, and the role that adsorbates may play in influencing the decay.
Surface Diffusion in Interactive Overlayers:
Authors: Tringides M. C. 
Published: March 2011

ABSTRACTThe analysis of surface diffusion in interactive overlayers deviates from the simple picture of diffusion as a random walk. Non-equilibrium processes (the growth of ordered or the disordering of already ordered islands) under constant coverage or deposition rate, can be easily used to measure surface diffusion. For the 0/W(110) system, such experiments measured an ordering activation energy ED=0.6±0.05 eV which is different from the one measured in disordering experiments ED=1 ± 0.05 eV. The difference can be accounted for by the interactions. Ordering experiments in the Ag/Si(111)-√3x√3R30 system under constant deposition, suggest the presence of non-thermal mobility.
Changes in Electronic Device Properties During the Formation of Dislocations
Authors: Ross F. M. , Hull R. , Bahnck D. , Bean J. C. , Peticolas L. J. , Kola R. R. , King C. A. 
Published: March 2011

ABSTRACTWe describe the results of an investigation into the formation and properties of dislocations in electronic devices. We have made electron transparent specimens from metastable GeSi/Si p-n junction diodes and introduced dislocations into the devices by heatingin situin the electron microscope. A modification made on the specimen holder for our microscope enables us to measure the characteristics of these devices while they remain under observation in the microscope. We can therefore observe the changes in the electrical properties of the devices as dislocations form. We confirm that the introduction of dislocations has a deleterious effect on parameters such as the reverse leakage current through a diode. However the magnitude of the effect we observe can not be explained by a generation-recombination process and instead we suggest a model based on the creation of point defects or the diffusion of metals during the formation of dislocations. We also consider the kinetics of dislocation formation, and in particular how the extent of dislocation formation in a device depends on the subsequent processing steps which it undergoes.
Seeded Heteroepitaxy and the Overgrowth of InN Films: Nucleation with Lattice Mismatched AIN
Authors: Kistenmacher Thomas J. , Ecelberger Scott A. , Bryden Wayne A. 
Published: March 2011

ABSTRACTThe growth and properties of thin films of InN on a variety of substrates nucleated by a 400Å layer of AIN have been shown to be dependent on the lattice mismatch (LMM) with the substrate. Examples are drawn from growth of InN thin films by reactive magnetron sputtering on high symmetry faces of a variety of crystalline substrates [(00.1) sapphire, (111) silicon and (111) yttria-stabilized zirconia, and (001) mica] and amorphous fused quartz. Striking is a comparison of the electrical transport properties for nucleated and unnucleated InN films. For example, the ratio of the Hall mobilities for nucleated and unnucleated InN films deposited on (00.1) sapphire (LMM for AIN and InN of 13.0% and 29.0%, respectively) is ∼102, while this ratio for nucleated and unnucleated InN films on (111) zirconia (LMM for AIN and InN of −14.8% and −7.8%, respectively) is ∼10−2. While all the factors underlying these results are not necessarily obvious, it is rather apparent that this trend in Hall mobility stems from a contrasting trend in film resistivity at a more nearly constant value for the carrier concentration.
Evolution of Electrical Properties with Thermal Annealing for Seeded Heteroepitaxial InN Thin Films
Authors: Bryden Wayne A. , Ecelberger Scott A. , Kistenmacher Thomas J. 
Published: March 2011

ABSTRACTTwo related studies of the effects of elevated temperature annealing on reactive rf magnetron sputtered InN films have been conducted. In the first study, thin films of InN were deposited and annealed in 5 mTorr of nitrogen gas using a conventional high-vacuum (HV) magnetron sputtering system. Films were grown at 100°C and following annealing at an elevated temperature (Ta) for 4 hours were removed from the system for physical characterization. The physical properties of the annealed films improved with thermal treatment and were strikingly coincident with the properties of a second set of films grown at Ta. In the second study, films were deposited at 400°C in 5 mTorr of nitrogen gas using an ultrahigh-vacuum (UHV) sputtering system. Samples were annealed (at 550°C) and electrically characterized under UHV conditions using a custom designed annealing furnace with an integral Van der Pauw probe. Contrary to expectations, the carrier concentration of these films showed a steady decrease with extended annealing and the carrier mobility nearly doubled after 15 hours of treatment.
Interfacial Morphology of Selicides Formed Via Rta of Sputtered Bi- and Multi-Layer Co/Ti(O,C) on Si
Authors: Hong Feng , Patnaik Bijoy K. , Li Bingzong , Liu Ping , Sun Zen , Rozgonyi George A. 
Published: March 2011

ABSTRACTCobalt silicide formed by diffusion of Co through a Ti compound has been reported for both bilayer and multilayer Co/Ti-Si structurest[2-4]. To compare the bilayer and multilayer systems in terms of the Co silicide interfacial morphology, both bilayers and six layers of 20nm Co and lOnm Ti were sputter deposited on (100)Si in a system where background. oxygen and carbon were gettered by each Ti layer. The samples were annealed from 550°C to 800°C for 60 sec by lamp RTA in N2 ambient. XTEM micrographs revealed that significant differences in interfacial morphology existed between bilayer and multilayer samples. The interfacial amorphous Ti(O.C) diffusion barrier layer was found to be more effective in the multilayer system producing uniform CoSix layers as thin as ∼5nm after 550°C RTA, whereas the silicide formed in the bilaver samples under the same condition was rough. RBS analysis showed that the transformation temperature from CoSi to CoSi2 was 800°C in bilayers and even higher for multilayers. The higher transformation temperature is attributed to the additional Co available in the multilayer system and its effect on Co monosilicide phase stability as previously reported[10].
Some Comparisons of Ag Deposits on Ge and Si(111)
Authors: Metcalfe F. L. , Venables J. A. 
Published: March 2011

ABSTRACTCrystal growth and surface diffusion have been studied in the Ag/Ge(lll) system using UHV-SEM based techniques, biassed secondary electron imaging (b-SEI), micro-AES and RHEED. Ag was deposited through and past a mask of holes held close to the substrate at 300<Td< 775K. Under certain conditions, the Ag patches were observed to split into two regions corresponding to the √3×√3R30° (hereafter √3) and a lower coverage 4×4 structure, each of which were easily observable using b-SEI. These patch widths were measured as a function of Td, and of annealing times at temperatures Ta, and effective diffusion coefficents extracted. The diffusion length of adatoms over the 4×4 structure is larger than that over the √3 structure. These observations are modelled using kinetic rate equations, and the results are compared with previous studies of Ag/Si(111). We find that energies characterising processes on top of the √3 layers of both systems are very similar, but that processes involved in the formation of the layers are quite different. The coverage of the √3 Ag/Ge(111) layer is close to 1 ML for all Td studied, unlike √3 Ag/Si(111). where it depends on deposition and annealing conditions.
Non-Destructive X-Ray Diffraction Analysis of the Under-Film Corrosion Processes in Zinc-Coated Steel Sheets by Synchrotron Radiation
Authors: Nose K. , Kawasaki K. , Hayashi K. , Morikawa H. , Sasaki S. 
Published: March 2011

ABSTRACTA highly brilliant x-ray beam from a synchrotron radiation source is a powerful tool to perform non-destructive x-ray diffraction analysis of an under-film corroded region of zinc-coated steel sheets. Investigations to identify corrosion products under the outdoor salt-spray test condition and to reveal their one-dimensional distribution were carried out Simonkolleite (ZnCl2•4Zn(OH)2 ) was identified for the first time at the tip of the under-film corroded region. By the one-dimensional analysis, it was shown that the x-ray diffraction intensity of simonkolleite increased, where that of metal zinc decreased. It was suggested that simonkolleite was formed as the first corrosion product under the outdoor salt-spray test condition.
Observation and Characterization of the Pseudomorphic to Stable Phase Transitions of Fe1-xSi on Si(111)
Authors: Onda N. , Sirringhaus H. , Goncalves-Conto S. , Schwarz C. , Muller-Gubler E. , Von Kanel H. 
Published: March 2011

ABSTRACTPseudomorphic Fe1-x Si films have been grown on Si(111) by molecular beam epitaxy (MBE) at room temperature (RT). Structural investigations revealed that the phase crystallizes in the cubic CsCl structure with a lattice constant close to half that of Si. Upon annealing, films thicker than 15Å undergo a phase transition to the stable bulk ε-FeSi, either in epitaxial or in polycrystalline form at temperatures around 300°C. Thinner films do not transform to the ε-FeSi phase. Instead they exhibit a continuous increase of the Si content up to the stoichiometry of FeSi2 The CsCl symmetry persists, exept for prolonged annealing close to the transition to βFeSi2, where γ-FeSi2 (CaF2 ) forms as an intermediate phase.
Formation Mechanism of Epitaxial CoSi2 Films on (001) Si Using Ti-Co Bimetallic Layer Source Materials
Authors: Hsia S. L. , Tana T. Y. , Smith P. L. , Mcguire G. E. 
Published: March 2011

ABSTRACTThe mechanism of formation of epitaxial CoSi2 film on (001) Si substrate, produced using sequentially deposited Ti-Co bimetallic layer source materials for which Ti was deposited onto the Si substrates first, has been studied by observing the Co silicide formation processes and structures in samples prepared by isochronal annealing and by isothermal annealing. The results demonstrated that, in leading to epitaxial CoSi2 film formation, Ti has played two roles. It has served as a barrier material to Co atoms and thus preventing Co2Si from forming. More importantly, it has allowed nucleation and growth of epitaxial-CoSi2 to dominate the Co silicide film formation process, apparently because it has served as a cleanser to remove native oxide from the Si substrate surface.
Stm Observation of Solid Phase Epitaxy Processes of Ar-Sputtered Si(100) Surfaces
Authors: Uesugi Katsuhiro , Yoshimura Masamichi , Yao Takafumi , Sato Tomoshige , Sueyoshi Takashi , Iwatsuki Masashi 
Published: March 2011

ABSTRACTScanning tunneling microscopy (STM) is used to investigate the surface morphology of Ar+-ion bombarded Si(100) surfaces and to elucidate the very beginning stages of solid phase epitaxy (SPE) processes of the Ar+-ion bombarded Si surfaces. The Ar+-ion bombarded Si surface consists of hillocks of 1–2 nm in diameter and 0.35–0.75 nm in height. The onset of SPE initiates at around 590°C, at which temperature a (2×2) structure surrounded by amorphous regions is partially observed on terraces of the surface. During annealing at 590–620°C, the areas of the c(2×2) and c(4×4) reconstruction surrounded by amorphous regions develops. New defect models for the (2×2) and c(4×4) structures are proposed w here alternating arrangements of the buckled dimers together with missing dimer defects are considered. On the other hand, after thermal annealing of the Ar+-ion bombarded Si at 830°C for 10 sec, terraces of (2×1) and (1×2) orientations arc observed on the surface, and pyramidal structures on a nanometer-scale which consists of double-layer step edges (dimer rows perpendicular to terrace edge) arc observed.
High Resolution X-Ray Diffraction of Hg1-xMnx Te Epitaxial Films
Authors: Tanner B K , Hallam T D , Funaki M , Brinkman A W 
Published: March 2011

ABSTRACTEpitaxial films of Hg1-xMnxTe (MMT) have been grown by direct alloy growth MOVPE. Perfection of layers grown on CdTe buffered GaAs, and unbuffered CdZnTe substrates has been assessed by double axis X-ray diffraction. No significant difference was observed in the rocking curve full width at half maximum (FWHM) between layers grown on the two types of substrate. Rocking curves taken as a function of position across the layer showed substantial variation, there being a very good correlation between layer thickness determined from the intensity of the substrate peak, layer rocking curve FWHM and Mn composition determined from the substrate and layer peak splitting. The contour maps of these parameters are discussed in terms of depletion of the DIPTe precursor.