bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction Between Co and SiO2 During Ion-Beam Mixing and Rapid Thermal Annealing
Authors: Dehm C. , Kasko I. , Burte E. P. , Ryssel H. 
Published: March 2011

ABSTRACTFor the application in self-aligned processes, it was supposed that CoSi2 could be superior to TiSi2, since, unlike Ti, a reaction between Co and SiO2 was not observed up to now. We studied the reaction of Co and SiO2 during ion-beam mixing and rapid thermal annealing (RTA). The influences of As and Ge implantation energy and dose were investigated in the range of 50 to 200 keV and 1–1014 to 5–1015 cm2. The annealing temperature was varied between 700° C and 1100°C.It could be demonstrated that the Co concentration in SiO2 rises with increasing Ge and As energy and dose up to values of 5·1015 cm2 compared to 2·1012 cm2 in unim-planted, annealed samples. The Co profiles in SiO2 were also studied by secondary ion mass spectroscopy (SIMS) and compared with Monte-Carlo simulations indicating pure ballistic mixing. Plan-view and cross-section transmission electron microscopy (TEM) were used to examine the SiO2 surface as well as the Co-SiO2 interface. These investigations revealed that ion-beam mixing with doses at or above 5·1014 cm2 and subsequent annealing does not damage the SiO2 unlike to unimplanted, annealed samples which show a rather severe structural change of the SiO2 surface increasing with rising annealing temperatures.
Metalization of Oriented Crystalline Films on Amorphous SiO2/Si
Authors: Luo Li , Nastasi M. , Maggiore C. J. , Pinizzotto R. F. , Yang H. , Namavar F. 
Published: March 2011

ABSTRACTTo meet the needs for vertical integration in microelectronic devices, metalization should not only provide required conducting properties, but should also be suitable for further epitaxial growth so that multilayer structures or heterostructures can be formed. For Si based electronic devices, this has been hindered by the amorphous nature of SiO2. SiO2 layers have been extensively used to passivate the Si surfaces and act as dielectric insulators for forming integrated circuits. In this study, we show that high quality, oriented, metallic nickel disilicide (NiSi2) thin films can be formed on SiO2/Si by combining both ion implantation and e-beam evaporation techniques. The orientation of the Si substrate is maintained in the NiSi2 film as if the SiO2 is not present. RBS/ion channeling and TEM were used to characterize the structures formed and the results indicated that the metallic NiSi2 films were comparable with the films made directly on Si under the same deposition condition. This method should, in general, be applicable to other suicides that have been epitaxially grown on Si.
Deposition of tungsten on silicon dioxide by GeH4 reduction of WF6
Authors: Oosterlaken T. G. M. , Leusink G. J. , van der Jeugd C. A. , Janssen G. C. A. M. , Radelaar S. 
Published: March 2011

ABSTRACTChemical Vapour Deposition of tungsten on silicon dioxide by means of GeH4 reduction of WF6 is studied. The influence of the ambient gas on the nucleation of tungsten is examined. Experiments have been performed in both Ar and H2 ambient. It is found that an Ar ambient hinders nucleation on silicon dioxide in comparison with a hydrogen ambient. Adhesion of the film and uniformity over the wafer are acceptable for the films deposited in hydrogen ambient.
Hetero n-i-p-i Structures for Nonlinear Optics and for Studies of Charge Carrier Transport
Authors: Kost Alan 
Published: March 2011

ABSTRACTThe use of large optical nonlinearities in hetero n-i-p-i structures to study charge carrier transport is discussed. A short history of hetero n-i-p-i's and a summary of related semiconductor microstructures are also presented.
Application of Surface Photovoltage Spectroscopy in Surface Analysis
Authors: Baikie Iain D. , Venderbosch Eimert , Hall Birgitta 
Published: March 2011

ABSTRACTExtension of the Kelvin probe vibrating capacitor technique of measuring work function, via Illumination of the semiconductor surface, i.e., Surface Photovoltage Spectroscopy (SPS), has many potential applications in the field of surface analysis.The combination of broad-band (white) and monochromatic radiation, together with measurement of the dark signal permits complete characterisation of the semiconductor work function via determination of the electron-affinity, surface potential and Local DensIty-of-States (LDOS). The work function is an extremely sensitive indicator of a wide range of surface processes, e.g., particle adsorption, stress, defect creation, phase-transitions, etc.We Illustrate application of this technique in the study of the temperature dependent initial oxidation behaviour of p-type Si(111) 7×7 between 100 and 300 K. The SPV response of the clean surface at 100 K corresponds to the capture of photo-stimulated electrons by a band of surface states centered around 1.4, 1.7, 1.9 and 2.4 eV. This response completely disappears at the peak of the (dark) work function change (0.3L) corresponding to a near complete removal of dangling bond states. The temperature-dependent white-light SPS response permits determination of the band-bending throughout the adsorption process. We observe that at 100 K the band-bending substantially decreases during the initial adsorption phase (0.1 L), after this dose it remains constant. However at 300 K the band-bending decreases much later, i.e., >10 L, in conjunction with oxygen permeation through the surface layer.In conclusion Surface Photovoltage Spectroscopy SPS is a simple and flexible method which can be used to follow the rather complex changes occurring at the semiconductor surface. It is a non-contact, nondestructive technique which allows simultaneous determination of both semiconductor band-bending and electron affinity.
A Computer Assisted Study of Chaotic Behavior in Intrinsic Photoconductors
Authors: Serfaty Alicia , Joshi N. V. , Martin J. M. 
Published: March 2011

ABSTRACTThe present work confirms thee possibility of chaotic behavior in intrinsic photoconductors with one type of traps under high radiation intensity. The system shows two attractors and a strong sensitivity to the initial conditions.
Applying Kukhtarev's Charge Transport Model to Multiple Quantum-Well Hetero-Nipis
Authors: Mahgerefteh Daniel , Garmire Elsa 
Published: March 2011

ABSTRACTWe present a model for light-induced charge transport in long-period multiple-quantum-well hetero-nipi structures that is based on Kukhtarev's transport model developed for understanding photorefractive grating formation. We give a simple analytical expression for the steady-state space-charge field in a hetero-nipi under illumination as a function of light intensity.
Study of the Inhomogeneities in Semiinsulating GaAs and InP by Spatially Resolved Photoconductivity
Authors: Gonzalez M. A. , Jiménez J. , Martin P. , Sanz L. F. , Chafai M. , Avella M. 
Published: March 2011

ABSTRACTA high resolution spatially resolved photocurrent system to study bulk non homogeneities in semiinsulating GaAs and InP is described. [Fe+3] distribution is studied in InP. In undoped LEC semiinsulating GaAs a study of the relation of Photoquenching (PQ) and Enhanced Photocurrent (EPC) to the dislocation atmosphere is done.
Prospective Conducting Polymer Composite Materials
Authors: Ponomarenko Anatoliy T , Shevchenko Vitaliy G. , Kryazhev Yuri G. 
Published: March 2011

ABSTRACTInfluence of processing conditions on electrophysical properties of composite materials (CM) have been investigated. Metal powders, graphite, Z-ferrite and other fillers were used. Properties of CM were investigated in direct and alternating electromagnetic fields.
Vacuum Electroreflectance: Overcoming the Difficulties of Electrolyte Electroreflectance and Photoreflectance
Authors: Mioc Silvia L. , Raccah Paul M. , Garland James W. 
Published: March 2011

ABSTRACTA new technique for obtaining the electroreflectance (ER) spectrum, Vacuum Electroreflectance (VER), is introduced. In VER, the modulating electric field is applied capacitively using a transparent electrode as one plate and the sample as the other plate, with vacuum in between. In this geometry, cooling or heating is achieved without any sample preparation. Precise positioning is achieved by piezoelectric motors monitored by a HeNe interferometer, and cooling to 80 K by the Joule-Thompson effect. GaAs samples with different Si doping are used to compare VER to Electrolyte ER and Photoreflectance.
Controlled Growth of GaAs/AlAs(111)B Superlattices
Authors: Angelo J.E. , Hoehn J.W. , Dabiran A.M. , Cohen P.I. , Gerberich W.W. 
Published: March 2011

ABSTRACTIn this study, transmission electron microscopy (TEM) was used to investigate the growthconditions which produce the highest quality GaAs(111)B films by molecular beam epitaxy (MBE). Low-temperature growth using both As4 and arsine as an As2 source produced highly twinned structures, although the use of As4 provided for a smoother surface and slightly different defect structure. Two distinct twin boundaries, (112)A and (112)B, were identified by cross-sectional transmission electron microscopy (XTEM). The (112)A defect could be over-grown by a subsequent high temperature growth but the roughness associated with the (112)B defects only increased with further growth. High temperature growth of GaAs and AlAs films, while maintaining the GaAs(11)surface reconstruction, resulted in substantial reduction in the number of twins boundaries. We also found that GaAs(111)B layer quality and surface morphology can be further improved by a high temperature growth with low arsenic to Ga flux ratio of I to 1.5 ona slightly misoriented substrate.
Method of GaAs Growth on Single Crystal Si Substrate
Authors: Dorogan Valery V. , Kosyak V.A. , Trofim V.G. 
Published: March 2011

ABSTRACTIn the proposed method space and time temperature gradients are used for GaAs epitaxial deposition on Si substrates from liquid phase. Minimal Si substrate dissolution and preferential GaAs deposition from the liquid phase on Si substrate can be obtained by selecting dissolvents, requiring necessary gradients temperature values and times of active phases interaction. Because of nonuniformities in the etched Si substrate surface act as crystallization centres, the deposition process begins from GaAs island growth. Due to the dominate tangential growth rate, the separate single crystals coalesce into a GaAs monolayer.
MOVPE Growth of GaAs on Si Using Tertiarybutylarsine
Authors: Miyagaki S. , Ohkubo S. , Takai K. , Takagi N. , Kimura M. , Kikuchi Y. , Eshita T. , Takasaki K. 
Published: March 2011

ABSTRACTWe developed GaAs heteroepitaxy on a Si substrate by metalorganio vapor phase epitaxy (MOVPE) using tertiarybutylarsine (TBAs). When we preheated Si at 1000ºC in the atmosphere including TBAs, a carbide layer was formed on the Si surface. This led to polycrystalline GaAs growth. By carrying out high-temperature preheating in an H2 -only atmosphere and supplying TBAs after the preheating, we have successfully grown single-crystal GaAs with a mirror surface in a process completely free of AsH3.
A New Method of Identifying the Interfacial Structure in the Type-B CoSi2//Si(111) Bicrystal
Authors: Daykin A.C. , Kiely C.J. 
Published: March 2011

ABSTRACTA new method of identifying the interfacial structure in the type-B CoSi2//Si(l11) bicrystal is presented. It involves using the kinematic structure factor equation to calculate the levels of contrast which will arise in darkfield micrographs due to steps at the interface. These are then matched to the levels of contrast measured directly from experimental images using an optical densitometer. By analysing the contrast levels measured from the same region of the bicrystal in both g=400B-aCos2 and g=111B-aCos2 micrographs, it is shown that the experimental resultsare consistent with the 7-fold coordinated interfacial structure.
Formation of (1120) ZnO Films by Controlling the Selftexture and the Relaxation of Film Stress
Authors: Yamaguchi Takao , Fujimura Norifumi , Goto Seiki , Ito Taichiro 
Published: March 2011

ABSTRACTZnO film has a tendency to grow parallel to the <0001> axis. Therefore, it is difficult to obtain epitaxial or oriented films with any other orientation. Nevertheless, we obtained excellent epitaxial (1120) ZnO films on R-cut, (0112), sapphire by controlling the self-texture. Epitaxial (1120) ZnO on R-cut sapphire exhibits an anisotropic misfit at the interface. To clarify the growth mechanism, the stress relaxation was calculated by measuring the curvature of the substrate and the lattice spacings. The change in stress calculated by these two methods differs from each other. We discuss this discrepancy in terms of the growth mechanism.
Morphology and Low Temperature Electrical Transport in Heteroepitaxial Indium Nitride Films
Authors: Bryden W. A. , Ecelberger S. A. , Kistenmacher T. J. 
Published: March 2011

ABSTRACTThe correlation of low temperature electrical transport with the evolution of heteroepitaxy and morphology for sputtered indium nitride thin films has been studied. A series of indium nitride films were deposited at temperatures ranging from 50 -650 °C by reactive rf magnetron sputtering onto the (00.1) face of sapphire. Above 350 °C, a transition occurs from a continuous morphology, in which grains are in intimate electrical contact, to an open, porous morphology with poor electrical contact. This transition in morphology deeply affects the electrical transport of the semiconductor. At low deposition temperature, the electrical transport is dominated by the relatively weak intergrain scattering leading to films with moderate mobility. As the deposition temperature is raised, the increasingly porous nature of the film leads to a deterioration in electrical mobility. It is proposed here that the relevant physics of these films is analogous to that for granular solids with a distribution of electrical connectivities that suggests a scattering potential dominated by disorder. In fact, the temperature dependence of the resistivity is found to be analogous to that observed in disordered and amorphous materials. In particular, the resistivity is characterized by: 1) A very weak temperature dependence; 2) The observation of a resistance minimum; and, 3) A steep rise in the low temperature (<4K) resistivity that follows a T1/ dependence.
Partial Dislocations and Critical Thicknesses for Strained Layer Relaxation
Authors: Hwang D. M. , Bhat R. , Schwarz S. A. , Chen C. Y. 
Published: March 2011

ABSTRACTPartial dislocations and their associated stacking faults are identified as the primary defects responsible for the initial relaxation of tensile-strained layers of fcc structure. The critical thickness for the formation of 90° partial dislocations at the strained interface is almost a factor of two smaller than that predicted for the formation of 60° perfect dislocation. Microstructures revealed by transmission electron microscopy from strained layers of various lattice mismatches and thicknesses agree with the prediction of the standard free-energy minimization model.
Detection of Misfit Strain Relaxation in MBE Grown Si1-xGex Films by Dynamic Monitoring of Rheed Diffraction Features
Authors: Maes J.W. , Schannen O.F.Z. , Trommel J. , Werner K. , Radelaar S. , Balk P. 
Published: March 2011

ABSTRACTReflection high energy electron diffraction (RHEED) has been used to detect strain relaxation in SiGe during growth on <001>- oriented Si for various layer compositions and substrate temperatures. The RHEED-technique permits the dynamic monitoring of the in-plane lattice constant of the growing layer by measuring the distance between diffraction features. The actual RHEED pattern is recorded by a CCD camera and subsequently processed in real time by a computer. This way, the layer relaxation can be followed conveniently; a detection limit for a variation in the lattice constant of Δa/a=5.10−4 has been obtained.
Control of threading dislocations in lattice-mismatched heteroepitaxy
Authors: Schowalter L.J. , Taylor A.P. , Petruzzello J. , Gaines J. , Olego D. 
Published: March 2011

ABSTRACTIt is generally observed that strain relaxation, which occurs by misfit dislocation formation, in lattice-mismatched heteroepitaxial layers is accompanied by the formation of threading dislocations. However, our group and others have observed that strain-relaxed epitaxial layers of In1−xGaxAs on GaAs substrates can be grown without the formation of threading dislocations in the epitaxial layer. We have been able to grow strain-relaxed layers up to 13% In concentration without observable densities of threading dislocations in the epilayer but do observe a large number of dislocations pushed into the GaAs substrate. The ability to grow strain-relaxed, lattice-mismatched heteroepitaxial layers has important practical applications. We have succeeded in growing dislocation-free layers of ZnSe on appropriately lattice-matched layers of In1−xGaxAs.
Molecular Beam Epitaxy Growth and Structural Characterization of Si/GaAs Superlattices
Authors: Matyi R.J. , Gillespie H.J. , Crook G.E. , Wade J.K. 
Published: March 2011

ABSTRACTThe growth of high quality Si/GaAs superlattices on GaAs substrates using molecular beam epitaxy is described. A typical superlattice structure consisted of ten periods of thin (<5Å) layers of pseudomorphic silicon alternating with thick GaAs layers; typical GaAs thicknesses range from 100Å to 1850Å. In situ reflection high energy electron diffraction analysis of the structures during growth showed the silicon layers developed a (3 ×1) reconstruction, while the GaAs exhibited a (4×2)→(3×2)→(3×1)→(2×4) reconstruction sequence. Both observations agree with prior studies of the growth of embedded silicon in GaAs/Si/GaAs heterostructures. X-ray diffraction using the (004) reflection showed sharp and intense satellite peaks (out to 22 orders in one case), indicating a high level of structural quality. Very good agreement has been obtained between observed diffraction patterns and those calculated via dynamical simulation.
The Effect of Photoreactive Substituents on the Morphological Structure and Properties of BPDA-PPD Based Polyimides
Authors: Coburn John C. , Pottiger M. T. , Nader A. E. , Pryde C. A. 
Published: March 2011

AbstractAdding photoreactive substituents onto a biphenyldianhydride (BPDA) and p-phenylene diamine (PPD) poly(amic acid) precursor influences the onset of imidization and the development of anisotropy and crystalline morphology during processing and the resulting morphology and properties of the fully cured films. Amine salts shift the imidization to lower temperatures while the covalently bonded esters shift the imidization to slightly higher temperatures. Anisotropy of the photosensitive polyimides develops at higher cure temperatures compared to the poly(amic acid). The photoreactive substituents do not affect the crystal structure, but do influence the crystallite orientation and morphology. Out-of-plane coefficients of thermal expansion (CTEs), calculated from the volume expansivities of these systems, are an order of magnitude larger than the in-plane CTEs.
Water Transport Across Modified Polyimide Surfaces: Ion-Bombarded PMDA-ODA and BPDA-PDA
Authors: Clearfield H.M. , Furman B.K. , Bailey F. , Sheth N. , Purushothaman S. 
Published: March 2011

AbstractDurability of metal/polyimide (PI) interfaces is essential for the long term reliability of advanced microelectronics packages. In earlier work, we showed that water absorbed by the PI can affect durability because, at high temperatures, it migrates to the interface and oxidizes the metal. In this study, we have investigated water transport through PMDA-ODA and BPDA-PDA polyimides as a function of ion beam treatment. Thermal desorption mass spectrometry (TDS) and gravimetric water uptake measurements were correlated with XPS spectra obtained from modified films. Transport through films with unmodified surfaces is rapid as shown by water uptake, however uptake is slowed considerably by surface modification. Additionally, only modified films exhibit peaks in TDS spectra–the peak temperature and intensity scale with dose. High resolution XPS spectra taken after modification suggest a graphitic-like surface region independent of dose. However, the extent of this “damaged” region scales with the dose. From the TDS spectra, we determine that the activation energy for water diffusion through this layer is 12–15 kcal/mol.
Fatigue Failure Mechanisms in Pb95.5Sn2Ag2.5Solder Joints: a Combined SIMS/XRD Study
Authors: Scandurra A. , Torrisi A. , Spoto G. , Fragala I. , Puglisi O. 
Published: March 2011

AbstractThe effects of accelerated fatigue tests on the crack formation in 95.5%Pb-2%Sn-2.5%Ag and 95%Pb-5%Sn solder joints have been investigated. The fracture surfaces which form upon mechanical stress have been studied by SIMS and XRD techniques. They are always located in the solder layer and show grain growth of the Pb-rich α phase present in the phase diagram of the Pb-Sn and the Pb-Sn-Ag systems. Grain growth is accompanied by tin depletion. XRD patterns of samples after 1, 40, 80 fatigue cycles show no variations of lattice parameters of the phases present in the alloy thus ruling-out the formation of new phases under mechanical stress.
A New, Reliable Snap Cure Die Attach Adhesive.
Authors: Galloway David P. , Nguyen My N. 
Published: March 2011

AbstractWith the advent of new in-line assembly techniques and equipment such as high temperature wirebonders, equipped with rapid cure stations, came the need to develop a suitable, adhesive with high performance characteristics. Typical traditional die attach adhesives were found to be inadequate.The higher performance characteristics were determined by assembly characterization studies. A new type of rapid cure thermoset dieattach adhesive was then developed to fill the need of these more rigorous assembly requirements.Early testing showed the new material to possess the desired attributes, such as < 1% wt loss during cure, thermal stability well above 300°C, low ionic species and excellent adhesion strength after cure. In addition, the material is suitable for syringe dispensing at high speeds.In this paper, we will review the process performance goals, the material evaluation strategy, the various types of screening tests performed on all samples, and some of the findings from the assembly characterization studys. We will conclude with the reliability test results, comparing this new material with four other die attach adhesive samples. Emphasis is given to the overall success of using this evaluation strategy and to the reliable results of this new adhesive used in plastic Dual-in-line packages.
Electro-Optic Polymer Devices
Authors: Lytel Rick , Lipscomb Ferris , Ticknor Tony 
Published: March 2011

AbstractElectro-optic (EO)polymers, processed into thin multilayer films, exhibit large nonresonant EO coefficients and low dielectric constants from DC to multi-GHz frequencies. Orientation of the constituent nonlinear optical chromophores, usually accomplished by electricfield poling, provides an EO coefficient suitable for modulation of light beams propagating in the plane of the polymer film. Thus, EO polymers are ideally suited for applications in integrated optics.The field EO polymer integrated optics has been developing rapidly during the past several years. Recent advances include the formulation of poled crosslinked epoxies and guest-host polyimides exhibiting thermal stability at temperatures significantly higher than those previously achieved with thermoplastic acrylate chemistry. These developments are an essential first step toward achieving practical materials exhibiting stability to manufacture, assembly, and end-use in modem electronic systems applications. This paper provides an introduction to EO polymer waveguide devices for applications to electronic packaging and interconnection.