bluuebunny/crossref_metadata_2025_split huggingface dataset:
HIGH RESOLUTION ELECTRON MICROSCOPE STUDY OF CdTe-Cd0.6Mn0.4 Te SUPERLATTICES
Authors: CHOI C. , OTSUKA N. , KOLODZIEJSKI L. A. , GUNSHOR-a R. L. 
Published: March 2011

AbstractStructures of CdTe-Cd0.6Mn0.4Te superlattices which are caused by the lattice mismatch between suterlattice layers have been studied by high resolution electron microscopy (HREM). In thin-layer superlattices, the crystal lattice in each layeris elastically distorted, resulting in the change of the crystal symmetry from cubic to rhombohedral. The presence of the small rhombohedral distrotion has been confirmed through a phase contrast effect in HREM images. In a thick-layer superlattice, the lattice mismatch is accommodated by dissociated misfit dislocations. Burgers vectors of partial misfit dislocations have been identified from the shift of lattice fringes in HREM images.
PRESSURE—DEPENDENT MAGNETO—OPTIC MEASUREMENTS IN STRAINED—LAYER SUPERLATTICES AT LOW TEMPERATURES
Authors: JONES E. D. , SCHIRBER J. E. , FRITZ I. J. , GOURLEY P. L. , BIEFELD R. M. , DAWSON L. R. , DRUMMOND T. J. 
Published: March 2011

AbstractMagneto—optic studies on InGaAs/GaAs and GaAs/GaPAs strained—layer superlattices are used to determine the in—plane light—hole valence—band effective masses. Also, hydrostatic pressure—dependent magneto—optic studies have been performed on these samples for magnetic fields up to 65 kG andpressures to 4 kbar in the temperature range of 1.6 - 4 K. The experimental pressure coefficients of the band—gap energy and the effective mass in the InGaAs/GaAsSLS structures were determined.
SEMICONDUCTOR QUANTUM-WELL HETEROSTRUCTURES
Authors: Chang L. L. 
Published: March 2011

AbstractActivities in semiconductor heterostructures are reviewed, with focus on the fundamental physics aspects in the quantum regime and with emphasis on recent experimental observations. The GaAs-GaAlAs is used to illustrate the general electronic properties of interest, which are obtained through various measurement techniques. Other heterostructures, including III-V, II(IV)-VI, and IV materials, are covered to the extent that they exhibit new and specific features.
NOVEL MEASUREMENT OF THE BAND DISCONTINUITIES IN (Al,Ga)As HETEROJUNCTIONS
Authors: WILSON B. A. , DAWSON P. , TU C. W. , MILLER R. C. 
Published: March 2011

AbstractA novel method has been used to obtain a direct and accurate measure of the valence-band discontinuity AlyGa1−yAs/AlAs heterojunctions in quantum-well structures. The technique takes advantage of the crossover occurring at a critical Al concentration above which the indirect X minimum in the AlAs becomes the lowest-energy conduction band in the system. Within these “staggered” band alignment structures, photoexcited electrons and holes are spatially separated, and recombination occurs across the interface. The resulting emission fixes the valence-band offset to within 1% without accurate knowledge of other system parameters, such as effective masses and exciton or dopant binding energies. These measurements represent the first direct optical confirmation of staggered band alignments in this technologically important material system.
STRUCTURAL CHARACTERIZATION OF HgTe/CdTe SUPERLATTICES
Authors: PAINE B. M. , VREELAND T. , CHEUNG J. T. 
Published: March 2011

AbstractSuperlattices of HgTe and CdTe, grown on (100) and (111) CdTe, have been characterized by He ion backscattering spectrometry and x-ray double crystal diffractometry. Backscattering spectrometry gave basic information about the depth-distribution of layers, i.e. the number of layers in the superlattice, the thickness of CdTe overlayer and the location of damage in the underlying CdTe. Symmetric and asymmetric rocking curves gave information about crystal quality and layer thicknesses. Average strains in the directions perpendicular and parallel to the layer interfaces were obtained directly from the rocking curves. Strains and thicknesses of the HgTe and CdTe layers, as well as variations from layer to layer, were found by fitting the symmetric rocking curves with theoretical calculations based on a kinematic model for the diffraction. A tilt of the atomic planes in the epitaxial layers, relative to those in the substrate, was observed by means of rocking curves recorded from the same diffracting planes, but with reversed incident and diffracted beam directions.
THE DEFECT STRUCTURE OF ION-IMPLANTED AlxGa1−xAs/GaAs SUPERLATFICES
Authors: COOMAN B.C. DE , CARTER C.B. , RALSTON J. , WICKS G.W. , EASTMAN L.F. 
Published: March 2011

AbstractCross-sectional transmission electron microscopy (XTEM) has been used to study the defect structure and intermixing of ion-implanted and annealed AlxGa1−xAs/GaAs superlattices. The results show clearly that the layer intermixing depends on mass and energy of the implanted species and the annealing conditions. The temperature and duration of annealing determines mainly the amount of residual damage. In addition it was observed that in all cases the point-defects agglomeration was influenced by the strain field present at the layer interfaces; extended defects nucleate preferentially in the GaAs layers.
MONTE CARLO STABILITY ANALYSIS OF STRAINED LAYER SUPERLATTICE INTERFACES
Authors: DODSON BRIAN W. 
Published: March 2011

AbstractWe have developed a procedure, based on conventional Monte Carlo methods, to investigate the limits of stability of a strained layer superlattice (SLS) system as a function of lattice mismatch and layer thickness. The method is demonstrated by the analysis of two-dimensional Lennard-Jones SLS systems, for which the regime of absolute SLS stability is mapped out. Extension of the technique to three-dimensional silicon-like model systems is discussed, and appropriate model potentials for stability analysis of the Si/SiGe system are introduced.
MODULATION WAVELENGTH DEPENDENCE OF THE INTERDIFFUSION IN AMORPHOUS Si/Ge MULTILAYER FILMS
Authors: PROKES S.M. , SPAEPEN F. 
Published: March 2011

AbstractCompositionally modulated amorphous Si/Ge thin films with repeat lengths (wavelengths) between 4.8 nm and 5.83 nm have been prepared using ion beam sputtering. The interdiffusion coefficient was determined from the decrease in the (000) x-ray satellite intensities with annealing, and was found to be relatively large, so that it could easily be measured without crystallization occurring. The effect of copper and oxygen impurities was found to be negligible. The dependence of the interdiffusivity on the modulation wavelength is similar to that of an ordering system. The temperature and wavelength dependence in the range T = 550-630 K is described by Dλ = 1.47×10−10 m.s−1 exp(-l.6 eV/kT)(l-21.8/λ2(nm)). It is suggested that diffusion is governed by the breaking of one bond near a pre-existing dangling bond.
Surface Studies of Silicon with a High Resolution Transmission Electron Microscope
Authors: Gibson J.M. , McDonald M.L. , Unterwald F.C. , Gossmann H.-J. , Bean J.C. , Tung R.T. 
Published: March 2011

AbstractUsing a specially modified ultra-high vacuum, ultra-high resolution transmission electron microscope, in-situ cleaned Si surfaces have been examined with near atomic resolution. By annealing the edges of a <110> thin Si specimen in-situ, it is found that low energy surfaces form. A surprising observation is that the {113} surface is stable and reconstructed by dimerization to a very low dangling bond density. It is also found that a 7×7 surface peridoicity can be preserved at a buried Si < 111 > / amorphous Si interface.
LIGHT-INDUCED EXCESS CONDUCTIVITY AND THE ROLE OF ARGON IN THE DEPOSITION OF DOPING-MODULATED AMORPHOUS SILICON SUPERLATTICES.
Authors: Su F.-C. , Levine S. , Vanier P. E. , Kampas F. J. 
Published: March 2011

AbstractAmorphous semiconductor superlattice structures consisting of alternating n-type and p-type doped layers of hydrogenated amorphous silicon (a-Si:H) have been made by silane glow discharge in a single chamber system. These multilayered films show the novel phenomenon of light-induced excess conductivity (LEC) associated with a metastable state having a lifetime of order of days. This report shows that the LEC effect is quite dependent on the specific details of the deposition parameters, namely dilution of the silane with inert gas, substrate temperature and layer thickness. In order to investigate the origin of the LEC effect, argon dilution was used for specific regions of the structure. This experiment shows that the slow states are distributed throughout the layers, and are not concentrated at the interfaces.
X-RAY DIFFRACTION CHARACTERIZATION OF ELASTIC STRAIN IN COMPOSITION MODULATED LAYERED STRUCTURES
Authors: JANKOWSKI A. F. , STEINMEYER P. A. 
Published: March 2011

AbstractX-ray diffraction techniques are utilized to characterize the biaxial state of stress in thermal vapor deposited, composition modulated layered structures. Thin film systems, as Au-Ni, Cu-Pd, Ag-Pd, Cu-Ni and Cu-NiFe, have manifested the ‘supermodulus effect’ as a mechanical property. The concept of interlayer coherency gives rise to the notion of accommodating misfit strains between the layers. In turn, such large elastic strains have been shown to cause large increases in the elastic moduli (the ‘supermodulus effect’) of noble metals. In the present work, pole figures are used to determine the texture and crystallographic orientations of these foils, and standard x-ray methods are then used to quantify this strain with lattice parameter measurements and diffraction peak profiles.
Epitaxy of Arsenic-Pressure-Controlled MBE-Grown GaAs Layers
Authors: Wang Y.H. , Liu W.C. , Chang C.Y. , Jean M.S. , Liao S.A. 
Published: March 2011

AbstractSurface morphologies of the molecular beam epitaxy (MBE)-grown GaAs layers using the background-arsenic-pressure-control method were investigated. The growth parameters, such as substrate temperature, growth rate, epilayer thickness, As/Ga ratio, doping concentration, substrate type, etc., are related to the observed oval defect density. Protrusions and Ga-droplets caused oval defects during growth. The origin of the oval defects in our system is found to be the gallium oxide, not Ga "spitting" from the effusion cell.
Magnetic Resonance of Oxygen-Related Defects in Silicon
Authors: Michel J. , Niklas J. R. , Spaeth J.-M. 
Published: March 2011

ABSTRACTThe electron spin resonance (ESR) of a number of vacancy-oxygen complexes created in electron irradiated Si containing oxygen is briefly reviewed. In these centers the unpaired spin density is highly localised (50–70%) on two Si sites within the complex. The ESR spectra of several paramagnetic thermal donors (TD+) formed by annealing oxygen-rich Si at 450 °C for one to several hundred hours are reviewed as well as recent experiments under uniaxial stress from which for the ground state a 2 valley effective mass-like wavefunction was derived. Results of electron nuclear double resonance (ENDOR) experiments on the TD+ ESR line “NL8” are presented for the first time. They reveal that all TD's identified in IR-spectroscopy are superimposed in the NL8 ESR line and that upon growth of the TD the structure of the core and the symmetry of the TD's is not changed. The hyperfine interactions with up to 7 shells of Si nuclei of 5 TD+'s were determined. Their size and tensor orientations are consistent with the two-valley effective mass-like wavefunction. 4 TD's identified in ENDOR could be correlated with IR-bands from growth kinetics. Although the ENDOR experiments so far do not yet lead to a detailed TD model, the model possibilities are narrowed down considerably by these results. The core must consist of nuclei with very low magnetic abundancy. It is tentatively suggested, that the core contains an O2 molecule.
The Study of Oxygen Thermal Donors in Silicon by Photothermal Ionisation Spectroscopy
Authors: Griffin Jennifer A. , Navarro H , Genzel L 
Published: March 2011

ABSTRACTIt is well known that Czochralski-grown silicon contains up to 2×1018 cm-3 oxygen atoms. When this silicon is annealed at 450°C a series of “thermal” donors are formed. In this work we present the results of a study of annealed Czcochralski-silicon samples by Photothermal Ionisation Spectroscopy and IR transmission measurements. All previously reported thermal donors, which occur in the spectral region above 330cm-1, and hove ionisation energies 53–69.3 meV, are observed by us. Also, our experimental results show the presence of at least three previously unreported thermally formed donor transition series below 330cm-1. Our results indicate that the ionisation energies of these new shallow thermal donors would be 36.3, 37.0 and 37.4 meV. Assignments are made by comparison of the energy differences between excited states to those predicted by the Effective Mass Theory.
Energy Levels and Capture Cross-Sections of Thermal Donors in Silicon
Authors: Henry A. , Pautrat J. L. , Magnea N. , Saminadayar K. 
Published: March 2011

ABSTRACTThe electrical properties of thermal donors centers, generated after annealing CZ-silicon at 450° C are carefully evaluated. The energy levels are corrected for the Poole-Frenkel lowering are compared to the ionization energy of the dominant centers revealed by infrared absorption experiments. The capture cross sections are found to be ≈ 2 × 10-12 cm2 for TDI and ≈ 2 × 10-13 cm2 for TD2. Detailed examination of their temperature dependence reveals that they follow a common law σ α T-5.
A Unified Treatment of The Thermal Donor Hierarchies in Silicon and Germanium
Authors: Borenstein Jeffrey T. , Corbett James W. 
Published: March 2011

ABSTRACTThe hierarchies of thermal donor binding energies produced by annealing oxygen-containing silicon or germanium at ca. 450°C are explained by using a generalized perturbation model which involves a standard repulsion parameter for the interaction between agglomerating oxygen atoms and the shallow donor electrons. This model is capable of fitting the ground state ladders for both charge states of the thermal donors in both Si and Ge, since differences between the two ladders can–ee explained entirely by the change in the electron-effective-mass and dielectric constant of the host.
Studies of Oxygen Thermal Donor Formation Under Stress
Authors: Wang Paul W. , Corbett James W. 
Published: March 2011

ABSTRACTOxygen thermal donor formation under stress and following various pre-heat treatments was investigated by resistivity measurements. Thermal donor formation at 450°C, with and without bending stress, is monitored in p-type Cz-silicon following various heat-treatments. As has been shown by others, the thermal donor formation rate depends upon the pre-treatment of the samples. We find that the rate also depends on the stress, being faster, or slower, on the tensile side than on the compressed side depending on the pre-treatment.
Luminescence Properties of New Donors in CZ-Silicon
Authors: Vendage Ph. , Magnea N. , Saminadayar K. 
Published: March 2011

ABSTRACTWe report the observation of a new shallow donor center detected in CZ Silicon annealed at 600°C, by EPR and luminescence experiments. The binding energy varies between 30 meV and 17 meV with the annealing time, showing the presence of several centers. The creation rate of these new defects is favoured in carbon rich material. This series of defects is probably one of the components of the New Donors.
Nucleation & Growth of Octahedral Oxide Particles in Silicon: Oxygen Ion Implantation
Authors: Carpenter R. W. , Vanderschaeve G. , Varkera C. J. , Wilson S. R. 
Published: March 2011

ABSTRACTCzochralski silicon was implanted with oxygen at 0.4 and 3.5MeV to obtain concentrations near 1020 oxygen/cm3 in the implanted region. Following implantation the wafers were aged at about 1000°C for 7 hours, and the resulting precipitates were examined by HREM. A high density of octahedral SiOx precipitates (∼1015/cm3) was the dominant morphology. Plate type precipitates and dislocations were also present at lower density. The data indicate octahedra grow from the plates.
Computer Modelling of the Temperature Distribution in the Silicon Single Crystals During Growth and the Thermal History of the Crystal
Authors: Anttila O. J. , Tilli M. V. , Lindroos V. K. 
Published: March 2011

ABSTRACTComputer modelling of the silicon single crystal grown by the Czochralski method has been carried out in order to calculate the temperature isotherms as well as to evaluate the thermal history of the crystal. The aim of the present work is to find out to which extent the thermal history of the crystal can be altered without structural modifications of the single crystal furnace. Furthermore, another aim is to study the influence of external heaters, reflectors and cooling elements to the temperature isotherms as well as to the form of the solid-melt interface. The model developed so far takes into account the crystal diameter and the pull rate as well as the radiation from the heater, the crucible and the melt. Furthermore, the inclusive study of the cooling effect of the inert gas flow is under progress.
Quantitative Study of Metal Gettering in Silicon
Authors: Colas Etienne G. , Weber E. R. , Hahn S. 
Published: March 2011

ABSTRACTIntrinsic gettering of iron in silicon has been investigated with a novel quantitative approach. Concentrations of electrically active, interstitial iron were determined by Electron Pararnagnetic Resonnance before, and after, various annealing cycles, using Cz silicon with oxygen precipitates of different well defined morphologies. Significant differences in the gettering rate in as-grown Cz and Cz silicon with high temperature oxygen precipitates were found. High temperature treatments after metal gettering resulted in the re-emission of the transition metal atoms for both as-grown and high temperature precipitated Cz silicon. This allowed the conclusion that gettering took place via FeSi2 formation in these cases and did not involve any thermally more stable phases.
Chemical Origin of the Grain Boundary Carrier Recombination in Silicon Bicrystals
Authors: Battistella F. , Rocher A. , George A. 
Published: March 2011

ABSTRACTThe minority carrier recombination related to grain boundaries is studied by the SEM/EBIC technique. The specimens investigated are silicon bicrystals obtained by the Czochralski pulling process. The specimens are heated for 2 hours at 750°C in a neutral atmosphere. Heterogeneous recombination of the grain boundaries is then observed.X-Ray topography and Transmission Electron Microscopy (TEM) have been performed to determine the origin of the heterogeneous recombination. A direct relationship between the local recombination along the grain boundary and the precipitates localized at the interface has been established. The chemical origin of the precipitates is discussed.
Oxygen Effects on Plastic Flow During Growth of Dendritic Web Si
Authors: Spitznagel J. A. , Seidensticker R. G. , Lien S. Y. , Hopkins R. H. 
Published: March 2011

ABSTRACTThe possible effects of oxygen on plastic flow of Si ribbons during growth by the, dendritic web process are described. Cooling rates preclude homogeneous nucleation and growth of detectable SiOx precipitates. Calculated resolved shear stresses on {111} <110> slip systems arising from thermoelastic strains exhibit periodic oscillations in sign and magnitude. The dwell times at elevated temperatures corresponding to zero or low stress periods accompanying such sign reversals are shown to be sufficiently long to permit decoration and locking of dislocations by oxygen atoms.
Yield Stress of Czochralski Silicon–The Effect Of Impurities and Oxygen Precipitate Morphology
Authors: Lawrence J. D. , Tsai H. L. 
Published: March 2011

ABSTRACTQuantitative measurements of the mechanical properties of Czochralski silicon were made. Samples were strained in tension to determine the yield characteristics (at 800°C) of silicon crystals which had been subjected to various heat treatments and which contained various concentrations of oxygen and carbon. The heat treatments included single step, two step (nucleation and growth) and three step (dissolution, nucleation and growth) annealing. Carbon concentration was found to affect both the rate of oxygen precipitation and the resulting precipitate morphology but did not have a direct effect on the yield stress of unprecipitated samples. There was a clear correlation between the amount of precipitated oxygen and the magnitude of the upper yield stress in samples with the same initial oxygen concentration. Precipitation caused a reduction in the upper yield stress for all precipitate morphologies, but the reduction was less severe (for a given amount of precipitation) where the precipitates were fine grains (<200Å) than where they were larger polyhedra or plates.
The Role of Carbon and Point Defects in Silicon
Authors: Gösele U. 
Published: March 2011

ABSTRACTAn overview of the behavior of intrinsic point defects in silicon and their interaction with carbon is given for temperatures above about 500° C. The diffusive mechanism of carbon in silicon, which involves silicon self-interstitials, is treated in some detail and compared with the diffusion mechanism of oxygen. The solubility of interstitial carbon is estimated. Co-precipitation of carbon and self-interstitials or oxygen are dealt with in terms of simple volume considerations. It is proposed that the contradicting results on the influence of intrinsic point defect supersaturations on oxygen nucleation and precipitation may possibly be explained in the frame-work of opposite effects depending on the carbon concentration. Finally the influence of carbon on the incorporation and diffusion of gold in silicon is discussed.
Dlts-Studies on the “New Oxygen Donor” in Heat Treated and Hydrogenated CZ-Grown SI
Authors: Hölzlein Karlheinz , Pensl G. , Schulz M. , Johnson N. M. 
Published: March 2011

ABSTRACTCz-grown Si samples containing a high concentration of oxygen are investigated after various processing steps by DLTS. Heat treatments ranging from 500°C–1000°C are performed to study the formation and annihilation of the “New Oxygen Donor” (ND) traps. Hydrogenation at low temperature leads to a reduction of the ND trap states. The experimental results confirm the “SiOx Interface Model” which assumes two differing types of interfacerelated states.
The Subsurface Hydrogen Barrier Layer in Plasma-Treated Silicon
Authors: Jaworowski A. E. , Wielunski L. S. , Bambakidis G. 
Published: March 2011

ABSTRACTThe near-surface hydrogen profile was measured using the 15N hydrogen profiling technique in silicon. By depositing an adlayer of Al on the surface we were able to observe the separation of the near-surface hydrogen profile in silicon from the surface contamination layer. The hydrogen profiling of the near-surface region revealed the existence of a subsurface hydrogen layer which acts as a barrier to the transfer of hydrogen into the bulk. The observed subsurface layer is saturated with molecular hydrogen and its profile drops off sharply with increasing depth. The structure of this molecular hydrogen barrier and its thermal stability were studied.
Characterization of Dielectric Layers on Hydrogen Passivated Si Surfaces
Authors: Gregory J. A. , Dubé C. E. , Hanoka J. I. , Vayman Z. Y. 
Published: March 2011

ABSTRACTWe have Investigated the layer formed on Si surfaces passivated by a Kaufman Ion source using mixtures of hydrogen and hydrocarbons. Chemical, optical, and electronic techniques were employed to characterize this layer and Its effect on passivation of defects in the Si. The evidence Indicates that the layer Is a dielectric and probably has the formula Six C(1-x) (H). It does not appear to Impede the passivation of polycrystalline Si, but it does affect the reflectivity of the Si material, and also the barrier height In Schottky junctions. We suggest that a similar layer may be formed during other hydrogen/hydrocarbon plasma treatments of SI.