bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sulfidization in Alcoholic Solutions: A New Surface Passivation Method for GaAs
Authors: Bessolov Vasily N. , Ivankov Andrew F. , Konenkova Elena V. , Lebedev Mikhail V. 
Published: April 2011

AbstractA new approach to GaAs surface passivation is suggested which consists in the treatment of GaAs in sulfide solutions in which different alcohols are used as solvents. It has been found that the photoluminescence efficiency of sulfide-treated GaAs associates with the dielectric constant of the solvent being used. With the decrease of dielectric constant value the PL intensity of sulfidized GaAs increases. Sulfidizing in isopropanol-, butanol- or t-butanol-based solutions leads to the formation of sulfide coat which PL properties remain constant even after strong laser irradiation. The effect of the solvent on the GaAs PL efficiensy is explained whithin the framework of hard and soft acids and bases. Thus the use of alcohol-based sulfide solution with low dielectric constant value greatly reduces surface recombination losses in sulfide-treated GaAs.
Effects of Additive Elements on Electrical Properties of Tantalum Oxide Films.
Authors: Fujikawa Hisayoshi , Taga Yasunori 
Published: April 2011

AbstractTa2O5-based composite films prepared by magnetron sputtering have been investigated with respect to their dielectric properties. As additive third oxides, Y2O3 and WO3 were found to be effective in improving insulating properties without decreasing their dielectric constant. Furthermore, electrical properties of Ta2O5-Y2O3 films were investigated by measuring the current-voltage characteristics in the temperature range from 100 to 330 K. Measurement of temperature dependence of the leakage current revealed that the conduction mechanism at RT changed from the Poole-Frenkel type to the Fowler-Nordheim tunneling type by adding Y2O3 into Ta2O5. Based on the detailed analysis of the results, it is concluded that the addition of Y2O3 into the Ta2O5 film is effective in the reduction of defect density without high-temperature annealing and the alteration of electrical conduction mechanisms of the films.
Investigation of Free Exciton Properties in GaAs Epitaxial Layer
Authors: Fengmei Wu , Yi Shi , Parenteau Martin , Jorio Anouar , Youdou Zheng , Carlone Cosmo 
Published: April 2011

AbstractThe transition energy, the binding energy, the intensity, the broadening and the lifetime of the free-exciton transitions in GaAs epitaxial layer have well been investigated using photoconductivity measurement which is analyzed in term of an improved fitting model. We have found that as the thickness is increased, the bind energy increases, but both the intensity of the high excitonic level and the lifetime of the excitons decrease. These effects are attributed mainly to imperfections located near the surface of the epitaxial layer.
Transient Diffusion and Gettering of Au and Cu to Cavities in Si
Authors: Wong-Leung J. , Williams J. S. , Nygren E. 
Published: April 2011

AbstractThis paper addresses the diffusion and gettering of Cu and Au to internal cavities in Si introduced by H-implantation. Rutherford backscattering and channeling and cross-sectional transmission electron microscopy are the main analysis methods used. During annealing at temperatures and times typical of low temperature device processing conditions, we observe a transient gettering regime in which implanted Au and Cu segregate to cavities leaving metal concentrations in the Si lattice well below the solubility level. Longer times and/or higher temperatures are required for equilibrium to be reached. These results may have important implications for developing optimum gettering strategies during thermal processing of device structures.
Analysis of Dislocation Networks and Electronic Properties of Dendritic Web Silicon
Authors: Morelhão S. L. , Meier D. L. , Neugebauer G. T. , Bathey B. B. , Mahajan S. 
Published: April 2011

AbstractDuring the growth of dendritic web silicon, an ideal material for fabrication of high efficiency solar cells, a thin ribbon of silicon single crystal is obtained. Due to thermal stresses characteristic in this growth process, dislocations and residual stresses are observed in most ribbons. In this study, transmission X-ray topography was used for analyzing dislocation networks in as-grown web silicon. We were able to correlate minority carrier diffusion length with the configuration of the networks that are strongly affected by twin planes lying midway across the web thickness. Analysis of the networks is also useful in providing information regarding regions of high stress levels associated with a given growth environment.
Order and Disorder in Semiconductors
Authors: Queisser Hans J. 
Published: April 2011

AbstractThe astounding success of microelectronics rests on a simple materials principle : creating a highly purified and perfected , spatially ordered semiconductor matrix , whose electrical and optical properties may be selectively adjusted by local substitutions of host atoms by dopant atoms. This unique materials utilization differs remarkably from all earlier technologies , because the controlled, almost imperceptibly small disorder by doping (rather than the ordered host ) dominates the relevant properties ! Defect control is thus a major concern for semiconductor technology. Homogeneity is an absolute necessity for this strategy, but only a few of the semiconductors can be made so homogeneous as to suppress the strong deleterious effects of inhomogeneity. Recent advances are summarized : atomic resolution of defect analyses, multiatom reactions and hope for applications,contactless measurements, gettering as well as detailed theory of simulations. The emergence of novel quantum devices, with both reduced dimensions and reduced dimensionalities heralds a paradigm change, since the quantizing small geometries exert stronger influences than defects do; nevertheless, materials perfection and interface control remain prerequisites for these structures.
Deep Level Defects in GaN Characterized by Capacitance Transient Spectroscopies
Authors: Gütz W. , Johnson N. M. , Street R. A. , Amano H. , Akasaki I. 
Published: April 2011

AbstractElectronic defects in MOCVD-grown n-type GaN were characterized by conventional deep level transient spectroscopy (DLTS) and by photoemission capacitance transient spectroscopy (O-DLTS) performed on Schottky diodes. With DLTS two deep levels were detected with thermal activation energies for electron emission to the conduction band of 0.16 eV and 0.44 eV. With O-DLTS we demonstrate four new deep levels with optical threshold energies for electron photoemission of ∼ 0.87 eV, 0.97 eV, 1.25 eV and 1.45 eV. The O-DLTS apparatus and the measurement are discussed in detail. We also report characterization of the Au-GaN barrier height of the Schottky diode by internal photoemission.
Relation Between Structure and Carrier Lifetime in As-Implanted GaAs
Authors: Liliental-Weber Z. , Swider W. , Kagiichi H. , Claverie A. , Wang H. H. , Whitaker J. F. 
Published: April 2011

AbstractThe structure of As implanted GaAs layers before and after annealing are described and the relation between the structural quality and carrier lifetime was determined. Subpicosecond carrier lifetimes were found already for as-implanted layers, and this value changes only slightly after annealing in the temperature range up to 600°C. Annealing of As-implanted layers leads to the growth of As precipitates with a similar orientation relationship as those observed in low-temperature MBE-grown GaAs layers. However, it is still not clear whether point defects created by implantation or the As precipitates are responsible for the short carrier lifetime.
Radiative Recombination Processes in Boron Modulation-Doped SiGe Quantum Wells
Authors: Buyanova I. A. , Chen W. M. , Henry A. , Ni W. X. , Hansson G. V. , Monemar B. 
Published: April 2011

AbstractThe radiative recombination processes of the two-dimensional hole gas formed in SiGe quantum wells (QWs) due to modulation doping are studied in details by photoluminescence (PL) spectroscopy. Boron-modulation-doped Si/Sil−xGex/Si heterostructures grown by molecular beam epitaxy (MBE) are studied. It is shown that charge transfer of holes from the doped Si layers causes the filling of the SiGe QWs leading to an appearance of a broad asymmetric PL band with a characteristic sharp high energy cut-off and enhanced recombination near the Fermi edge. A reduction of this PL enhancement is observed with an increase of measuring temperature. The PL bandwidth and the high energy cut-off are found to vary with either the doping level or the spatial separation between the delta-doped layers and the QWs. This PL band is argued to arise from the recombination of the holes in the QWs and electrons confined near the QWs as a result of the band bending induced by the delta-doping. The shape of the PL band with enhanced intensity near the Fermi edge are discussed in terms of the phase space filling and many-body effects.
Introduction of Radiative Isoelectronic Complexes During Molecular Beam Epitaxial Growth of Si and Si1-xGex/Si Superlattices
Authors: Moore Karen L. , King Oliver , Hall Dennis G. , Bevk Joze , Furtsch Matthias 
Published: April 2011

AbstractRadiative isoelectronic impurity complexes consisting of pairs of Be atoms that bind excitons can be formed in both Si and SiGe/Si superlattices during growth by molecular beam epitaxy. We describe the conditions under which these radiative complexes can be formed and show that they can be localized in the alloy layers of a superlattice. Experimental results from samples with grown-in Be are compared to previous results from ion implanted samples. Superlattices of varying well widths are examined and a narrowing of the no-phonon linewidth is observed.
The Kinetics of Capture and Emission of Discrete DX Related Centers in Silicon Doped AlGaAs Using Time Analyzed Transient Spectroscopy
Authors: Agarwal Sandeep , Mohapatra Y. N. 
Published: April 2011

AbstractThe kinetics of multiple DX related emission centers are studied using the isothermal Time Analyzed Transient Spectroscopy (TATS) of constant capacitance voltage transients. Four distinct emitting centers have been obtained using higher order TATS in the same silicon doped Al0.33As0.67As sample without use of hydrostatic pressure. Accurate identification of the multiple DX states has allowed a better understanding of the charge redistribution process during capture. Improved resolution due to increase in order of spectroscopy has enabled quantitative fitting of spectral lineshape and thus accounting for degree of nonexponentiality associated with each of the four discrete centers. The capture kinetics of these centers are studied over six orders in magnitude of filling time. The resulting quality of kinetic data makes possible detailed quantitative comparison with kinetics predicted by positive U and negative U models of DX centers. We show that our data is in agreement with positive U model of DX center.
Adjacent Layer Composition Effects on Fetbco Thin Film Magnetic Properties
Authors: Hintz Michael B. 
Published: April 2011

ABSTRACTThe magneto-optical (MO) layer in current rare earth-transition metal (RE-TM) based MO recording media is typically 20 nm to 60 nm thick. It has been suggested, however, that media structures employing a multiplicity of thinner MO layers may be advantageous, e.g., for multilevel recording applications [1] or media noise reduction [2]. As magnetic layer thickness is reduced, interactions among magnetic layers and adjacent materials can have an increasingly large influence on magnetic properties; in many instances, these interactions can dominate the observed magnetic behavior.As a means of studying MO layer - adjacent layer interactions, we have used thin (≈3 nm) films of several materials to separate single 24 nm thick ion-beam-deposited FeTbCo layers into N thinner layers of 24/N nm thickness (N × 24/N). As N increases, the FeThCo magnetic properties generally change; however, the relative magnitude of the changes is strongly dependent upon the adjacent layer composition. Magnetization (Ms), energy product (MsHc) at 30 C and Curie temperature data for 1 × 24 nm structures and 6 × 4 nm structures are compared and discussed for specimens employing SiCx, Six, YOx, HfOx, Si and SiOx adjacent layer materials.
Interlayer Coupling in Magnetic/Pd Multilayers
Authors: Shi Zhu-Pei , Klein Barry M. 
Published: April 2011

ABSTRACTThe Anderson model of local-state conduction electron mixing is applied to the problem of interlayer magnetic coupling in metallic multilayered structures with palladium (Pd) spacer layers. An oscillation period of 5 spacer monolayers and the tendency towards ferromagnetic bias of the interlayer magnetic coupling that we obtain are consistent with the experimental data.
Crystal Structure Dependence of Antiferromagnetic Coupling in FE/SI Multilayers
Authors: Michel R. P. , Chaiken A. , Wall M. A. 
Published: April 2011

ABSTRACTRecent reports of temperature dependent antiferromagnetic coupling in Fe/Si multilayers have motivated the generalization of models describing magnetic coupling in metal/metal multilayers to metal/insulator and metal/semiconductor layered systems. Interesting dependence of the magnetic properties on layer thickness and temperature are predicted. We report measurements that show the antiferromagnetic (AF) coupling observed in Fe/Si multilayers is strongly dependent on the crystalline coherence of the silicide interlayer. Electron diffraction images show the silicide interlayer has a CsCl structure. It is not clear at this time whether the interlayer is a poor metallic conductor or a semiconductor so the relevance of generalized coupling theories is unclear.
Surface Anisotropy in Epitaxial FE(110)/MO(110) Multilayers
Authors: Osgood R.M. , White R.L. , Clemens B.M. 
Published: April 2011

ABSTRACTWe have prepared epitaxial Fe(110)/Mo(110) multilayers by sputter deposition. These films exhibit a large uniaxial anisotropy and may be attractive as islanded in-plane recording media. The large uniaxial anisotropy is due to the intrinsic surface anisotropy of the Fe(110)/Mo(110) interface, which is of the same magnitude as the surface anistropy of the Fe(110)/W(110) interface but has a different sign (the surface anisotropy of the Fe(110)/Mo(110) interface prefers the [001] axis of magnetization). The magnetoelastic component of the anisotropy is not large. A novel magneto-optic technique was used to measure the transverse component of the magnetization and deduce information about the anisotropy and domain structure of the multilayers.
Studies On Magnetic Configurations In Multilayers by A Quantum Spin Model
Authors: Kawazoe Yoshiyuki , Takahashi Manabu , Hu Xiao , Tao Ruibao 
Published: April 2011

ABSTRACTA method based on the variation of the magnetization direction of each layer and Holstein- Primakoff transformation is presented to estimate the magnetization configuration in a superlattice of quantum ferromagnetic system with an interface between perpendicular and in-plane easy-axis layers. Numerical results on the magnetization configurations under different applied magnetic fields, critical field, and critical anisotropic parameter are given.
Epitaxial Growth of (111) TbFe2 by Sputter Deposition
Authors: Wang C.T. , Osgood R.M. , White R.L. , Clemens B.M. 
Published: April 2011

ABSTRACTThe effect of in-plane strain in (111)-oriented epitaxial TbFe2 films on the magnetization orientations was studied. Magnetocrystalline anisotropy, shape anisotropy, and magnetoelastic energy were calculated to determine the magnetization orientation in the presence of various in-plane strains. Theoretical considerations indicate that a compressive strain smaller than -0.065% can induce an out-of-plane magnetization. DC magnetron sputtering from Tb and Fe elemental targets was used to grow 50, 100, 200, and 400 Å thick epitaxial TbFe2(111) films at 600°C on (110)-oriented sapphire substrates with 1000 Å thick epitaxial Mo(110) buffer layers. The growth rate of the TbFe2(111) films was 1.44 Å/sec. X-ray diffractometry, Rutherford backscattering spectrometry, and vibrating sample magnetometry were used to characterize the crystal structure, epitaxial orientation, composition, stress and strain state, and magnetic properties of the TbFe2 films. The TbFe2(111) films were epitaxial with twins rotated by 60° and were in tensile strain states with the resulting in-plane magnetization.
Growth and Characterization of Fept Compound thin Films
Authors: Visokay M.R. , Sinclair R. 
Published: April 2011

ABSTRACTFePt alloy films were deposited at 50 and 49°C onto amorphous SiO2 and single crystal [001] MgO and [0001] Al2O3 using DC magnetron cosputtering, resulting in polycrystalline and [001] and [111] epitaxial films, respectively. High temperature deposition resulted in ordered films with the tetragonal Ll structure and out-of-plane magnetic easy axes while low temperature deposition yielded chemically disordered fcc alloys with in-plane easy axes. Significant modification of the magneto-optic Kerr spectrum is observed for ordered relative to disordered alloys for all orientations. The Kerr rotation has a strong orientation dependence for the ordered, but not disordered films.
Structure and Magnetism in Mo/Co Multilayers
Authors: Foiles C.L. , Franklin M.R. , Loloee R. 
Published: April 2011

ABSTRACTThe magnetic and structural properties of Co in Mo/Co multilayers are an unresolved issue. Two independent studies report different structures for thicker Co layers in multilayers of comparable dimensions as well as significant differences in both the form and the layer thickness for a loss of ferromagnetism. Both studies base their structural claims on a limited number of Bragg lines. We have used x-ray diffraction, transmission electron diffraction, and EXAFS to probe the structure of Mo/Co multilayers having Co layer thicknesses from 4 to 63Å. Our structural and magnetic results for these samples are compared to those of the above studies and are contrasted with results for Mo/Fe multilayers having comparable dimensions.
In-Situ XPS Study of the Aluminum Poly(p-Phenylenevinylene) Interface
Authors: Konstadinidis K. , Papadimitrakopoulos F. , Galvin M. , Opila R. 
Published: April 2011

ABSTRACTThe chemical and electronic properties of aluminum/poly(p-phenylenevinylene) (PPV) interfaces were studied in situ using x-ray photoelectron spectroscopy (XPS). It was observed that the aluminum atoms react with the oxygen-containing groups present as impurities on the surface of PPV to form Al-O-C linkages. The Al atoms also interact with the wrsystem of the polymer as indicated by changes in the valence band. Contrary to to recent suggestions (Ettedgui et al.) the relation between surface oxygen content and band bending is not straightforward, as shown by deposition on PPV surfaces prepared by two different synthetic routes.
Effects of Surface Modification on the Structure of Adsorbed Block Copolymer Monolayers
Authors: Pai-panandiker Rahool S. , Dorgan John R. 
Published: April 2011

ABSTRACTImproving the processing and formability of ceramic components prior to firing (as green bodies) requires an enhanced understanding of how the polymeric binder components function. We report on the role of surface energetics on the structure of the copolymeric monolayers formed via adsorption from solution. Also, results on the effects of surface energetics on the kinetics of the adsorption are reported. A silicon wafer with an oxide layer is used as the surface and adsorption takes place from toluene. Surface energetics are varied by treatment of the oxide surface with a series of silane coupling agents which contain either amine, epoxide, or vinyl functional groups. The block copolymers used consist of relatively short poly(ethylene oxide) (PEO) blocks and much longer polystyrene (PS) blocks. Ellipsometry is used to determine the grafting density, σ (chains/nm2), and Fourier Transform Infrared spectroscopy is used to investigate the copolymer on the surface. It is seen that the time required to reach equilibrium increases as the strength of the interaction between the copolymer and the surface increases. Also, the diblock copolymers appear to obey the scaling laws proposed by Marques and Joanny on all the surfaces studied. ( i.e., σ ∝ 1/NA, when the copolymer is symmetric or moderately symmetric and σ ∝ 1/β2, when the copolymers are asymmetric, where NA is the number of segments of the adsorbing block and β is the ratio of the size of the nonadsorbing block to that of the adsorbing block.)
XPS Study of Buried Metal/Polymer and Polymer/Metal Interface
Authors: Wu P. K. 
Published: April 2011

ABSTRACTMetal/Polymer systems have potential applications as interconnect materials in integrated circuits. Polymers with low dielectric constants, if used as interlayer dielectric, can reduce the RC time constant. Device speed can be doubled if a polymer can replace the present dielectric material, SiO2. However, the problem of weak metal/polymer adhesion must be understood and resolved. In situ deposition and analysis are the most controlled means to study an interface formation process. However, for practical reasons, i.e., application, time, cost, and flexibility, it is critical to study metal/polymer interface ex situ. X-ray Photoelectron Spectroscopy (XPS), can be used to determine the composition and bonding structures of buried interfaces. This is achieved by examining peeled surfaces, thin overlayer, and lowenergy- ion sputtered surfaces. The possible adhesion mechanism or failure mode is determined by correlating XPS results with adhesion strength. Based on these results, adhesion enhancement methods, such as substrate surface treatments, can be formulated. The product of these treatments can be evaluated using the same analysis. These techniques for studying buried interfaces using XPS are reviewed and results of their applications to the metal/Teflon AF 1600 interface is presented.
Post CMP Cleaning Using Ice Scrubber Cleaning
Authors: Takenaka N. , Satoh Y. , Ishihama A. , Sakiyama K. 
Published: April 2011

ABSTRACTThe surface cleaning technology with the use of ice scrubber cleaning has been developed to remove the particles after Chemical Mechanical Polishing (CMP) process. The ice particles with a high speed nearly equal to the sound velocity bombarded the Si wafer surface, as a result, the residue from the slurry solution was reduced from ∼5/cm2 to ∼0.05/cm2 and the metal impurities are completely eliminated below the defect limitation for ICP mass spectroscopy. The charge build-up damage due to the high speed particles is not introduced into the the MOS capacitors. This technology is quite effective, compared with the conventional brush scrubber method and is applicable for the cleaning process below the quarter micron devices.
Determination of Organic Contamination From Polymeric Construction Materials for Semiconductor Technology
Authors: Budde Klaus J. 
Published: April 2011

ABSTRACTVolatile organic surface contaminants on silicon wafers lead to strong detrimental impact on semiconductor production yield and product reliability. Our model for the mechanism of impact is introduced and discussed.Only a few metrology methods are suited for the ultratrace detection of volatiles on surfaces and their identification. The data presented in this paper were achieved by ion mobility spectrometry followed by mass spectrometry (IMS/MS).Eleven commercial wafer storage and transport boxes were screened by sampling the contaminants onto silicon wafers at room temperature. In a second set of experiments, enhanced stress testing was performed at elevated temperatures for polypropylene, polycarbonate, polytetrafluoro ethylene, perfluoro alkoxy polymer, polyvinylidene fluoride and acrylonitrile-butadiene-styrene copolymer. From the outgassing behaviour of single contaminants, valuable information can be achieved.Test method E 46 (SEMI) samples the contaminants onto the wafer under the real conditions of use. The data for six virgin minienvironments are shown.