bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spontaneous Change of Growth Orientation of InGaP/GaAs Superlattices in MBE
Authors: Mahalingam K. , Nakamura Y. , Otsuka N. , Lee H. Y. , Hafich M. J. , Robinson G. Y. 
Published: March 2011

ABSTRACTThe influence of growth interruption during the MBE growth of (100) In0.5Ga0.5P/GaAs superlattices is investigated by cross-sectional TEM. It is observed that for certain combinations of interruption lengths and group V fluxes, the growth orientation of the superlattice changes spontaneously from [100] to <311> direction. V-shaped grooves with {311} facets form initially in the growth plane and eventually lead to the formation of regions of {311} superlattice structures. The direction of V-shaped grooves is along the [011[ axis, which is parallel to the surface dangling bonds of the group V atoms in the unreconstructed (100) plane. The most critical stage for the spontaneous change of the growth orientation is the interruption after the growth of a GaAs layer with the P2 flux. Our observations suggest that small but stable {311} facets form at this stage and develop into well-defined {311} growth planes during the growth of the GaAs layer.
A Study of FeAl/AlAs/GaAs Interfaces Using Moiré-Fringe Contrast in a Transmission Electron Microscope
Authors: Angelo J. E. , Kuznia J.N. , Wowchak A.M. , Cohen P. I. , Gerberich W. W. 
Published: March 2011

ABSTRACTThis paper describes the transmission electron microscope (TEM) investigations of the defect structure present at various FeAl/AlAs/GaAs interfaces. Although a systematic study has not yet been completed it is shown that by changing the growth temperature from 200°C to 300°C the growth morphology changes significantly. In-situ RHEED studies show the growth mode changes from layer-by-layer to island-like when the growth temperature is increased. TEM in both plan-view and cross-sectional modes is used to confirm these results. It is found that by increasing the growth temperature from 200°C to 300°C the growth mode switches from layer-by-layer (2D) with a continuous FeAl film, to island-like (3D) with significant numbers of “pin-holes”. A Moiré-fringe analysis is applied to determine the Burgers vector of the misfit dislocations. In both cases the interface between the FeAl and AlAs consists of a grid of misfit dislocations with [100] and [010] line directions whose Burgers vectors are [010] and [100] respectively.
Island Dynamics in Film Aging
Authors: Marsh S. P. , Glicksman M. E. 
Published: March 2011

ABSTRACTA theory is presented which describes the capillary-driven aging of discontinuous thin films on a substrate, where the primary transport mechanism among the domains is two-dimensional diffusion of species over the substrate. This theory employs a statistical dynamics formulation, whereby the average growth rate for each domain size class is determined relative to the critical (zero-growth) domain size. The time dependence of the critical size is determined through a global constraint on the individual fields. The effect of fractional area coverage, Aa, is accounted for through a second global constraint over the distribution of island sizes.This theory yields a self-similar size distribution that is fairly insensitive to Aa. The critical island radius, R*, is found to increase asymptotically as the cube-root of time. The growth rate of R* increases with Aa, which results from the closer proximity of the islands and steeper concentration gradients as Aa increases.
Thickness Dependence of Epitaxial TiSi2 on Si(111).
Authors: Jeon Hyeongtag , Honeycutt J. W. , Sukow C. A. , Rozgonyi G. A. , Nemanich R. J. 
Published: March 2011

ABSTRACTThe epitaxy and morphology of TiSi2 on Si(l 11) are studied as a function of Ti thickness. Titanium thicknesses of 1–2 monolayers and Ti films with thicknesses of 50Å; were examined. The titanium silicide films were formed on atomically clean Si substrates by ultrahigh vacuum (UHV) deposition of Ti followed by in situ annealing. In situ LEED and AES measurements characterized the reaction process. For room temperature deposition of less than two monolayers of Ti the LEED pattern associated with the reconstructed substrate disappeared, and the 1×1 bulk pattern also disappeared completely. Annealing at 200°C resulted in a decrease in the Ti AES signal indicating interdiffusion. For annealing up to 500°C, a series of changes in the LEED patterns were observed, which indicated that the disordered layer transformed to an ordered surface layer. Annealing to higher temperature resulted in the reappearance of the diffraction pattern associated with the 7×7 reconstructed Si(111) surface. This indicated three dimensional island growth. For the TiSi2 formed by in situ annealing of 50Å of Ti on Si(111), three different types of island morphologies were observed and identified as the C49 phase of TiSi2. The C49 TiSi2 was proven to be an epitaxial titanium silicideby HRTEM and SAD. Two different orientation relationships of the TiSi2 islands are found: 1) [3 1 1] C49 TiSi2 // [112]Si and (130) C49 TiSi2 //(11 1) Si, and 2) [1 1 2] C49 TiSi2 // [110] Si and (021) C49 TiSi2 //(1 11) Si. The C49 nucleation and island morphologies are discussed in terms of the character of the epitaxial interface.
Effects on TiN Film Properties of the Interaction Between Titanium and Borophosphosilicate Glass During High-Temperature Nitridation
Authors: Galovich C. S. , Lee S. S. , Kwong D. L. 
Published: March 2011

ABSTRACTTitanium nitride, formed either by rapid thermal processing (RTP) or reactive sputtering, is commonly applied as a barrier film in the fabrication of metal-to-substrate contacts for CMOS devices. In one approach a titanium film is sputtered onto a patterned dielectric and then nitrided at a temperature greater than 500° C to form a TiN layer. Variations in the structure and resistivity of the titanium layer are observed when the titanium overlies a borophosphosilicate glass (BPSG) film. The structural change appears as a “wrinkling” of the TiN film and the TiN/BPSG interface. More severely wrinkled films are characterized by lower sheet resistivities. Results of TEM and SEM analyses are presented, as well as data on TiN resistivity and reflectance for nitridation temperatures in the range 650°C to 900°C, and for BPSG boron and phosphorus concentrations of approximately 3 to 5 wt. %. Mechanisms for the TiN wrinkling are discussed.
Layer Formation in CuNi/C X-Ray Optics
Authors: Jankowski A. F. , Stearns D. G. 
Published: March 2011

ABSTRACTA series of Cu/C and CuNi/C multilayer films are prepared for potential use as normal incidence x-ray reflectors. The use of a metal alloy layer is intended to enhance layer formation without metastable metallic carbide formation. The films are characterized both in composition and structure. Addition of Ni to the Cu-rich layer is seen to markedly improve the formation of continuous metal layers.
Diffuse Light Scattering as a Probe of Buried Interface Reactions
Authors: Pantojas V. , Cabral C. , Harper J. , Persans P. D. 
Published: March 2011

ABSTRACTWe report the application of diffuse light scattering to study buried interface reactions. As a model system we discuss the annealing of thin Cu/Al bilayers. Samples were prepared by evaporating Cu/Al and Al/Cu bilayers onto SiO2 covered Si wafers at room temperature. The Cu-Al thickness ratio was chosen to yield an average composition of CuAIt. When bilayers are annealed at 200–250°C the scattering intensity increases by about a factor of five above the as-deposited samples. We believe that this increase is partially due to the non-uniform reaction at the Cu/Al interface and partially to the mottled surface formed when leading growing parts of the reaction layer reach the surface. The relative contribution from this scattering mechanism is discussed quantitatively. For higher annealing temperature(300–350°C) the scattered light intensity falls again almost to the original level, suggesting that the Al/Cu reaction is complete and that the surface is homogeneous and smooth. For higher temperature anneals (400–500°C) the scattering once again increases, mainly due to the natural monotonic increase in surface roughness when metals are annealed. Control samples of the pure metal on Si02 show only the high temperature roughening effect.
Coarsening Phenomenon of Si Clusters
Authors: Kumomi Hideya , Yonehara Takao 
Published: March 2011

ABSTRACTCoarsening phenomenon is observed among crystalline Si clusters which are deposited over silicon-oxide and -nitride surfaces by chemical vapor deposition using HC1 as an etching gas. As soon as the deposition starts, submicron-sized fine clusters nucleate and increase in number, but do not grow in size. Micron-sized large clusters emerge among the fine ones, gradually increase and rapidly grow, while the preexisting fine ones disappear finally. It is found that the fine clusters must be etched away into vapor again by HCl or reevaporated.
Time Dependent Deformation in Polymers
Authors: Shinozaki D.M. , Klauzner A. 
Published: March 2011

ABSTRACTTime dependent deformation of polymers must be considered in studies of deformation and fracture of polymer electronic packaging materials. In composites in which fabrication stresses are stored, the rate of plastic relaxation influences the long term mechanical stability. The practical need to predict mechanical performance of these materials from simple mechanical tests is the motivating factor in attempting to relate fundamental mechanisms of deformation to the stress relaxation behaviour. A review of some approaches based on activated rate processes and their application to some preliminary experiments onpolyimide is reported.
Thermal Properties Evaluation of Thin Films, Wafers And Substrates
Authors: Tye R.P. , Maesono A. 
Published: March 2011

ABSTRACTMaterials in use or under consideration for many applications in new and emerging technologies are often available only in small quantities and many times in the form of thin films, wafers and sheets. Such size and form limitations present a number of challenges to those wishing to evaluate thermal performance characteristics. This has resulted in a need to develop totally new transient or modify current transient and steady state techniques significantly. Various new or modified techniques to measure thermophysical properties are described. Illustrations of, applications to and results on semiconductors, superconductors, diamonds, polymers, composites and layered structures will be discussed.
Toward Measurement of Thin Film Properties by Enhanced Moire Interferometry
Authors: Voloshin Arkady S. , Erdogan Fazil , Tsai Leng-Tsun 
Published: March 2011

ABSTRACTGrowing use of thin films in encapsulated integrated circuits(IC's) necessitated new developments in measurement of their mechanical properties in-situ. This can be done by a hybrid analytical experimental approach. The films are approximated by orthotropic membranes and the substrate is assumed to be an elastic continuum. It can be shown that power of stress singularity is a function of geometry and film/substrate material properties. By loading the sample and measuring actual displacement field in the close proximity to the crack or edge, one can evaluate the needed properties.The technique used to measure full field displacements is enhanced moire' interferometry. It is based on the formation of fringes by the coexistence of light wave fronts diffracted from a specimen grating of high frequency. These specimen gratings are created on the specimen surface using a replication technique from a specially prepared mold. Two beams of coherent laser light illuminate the specimen grating obliquely to create a virtual reference grating in front of the specimen. The frequency f of this grating is chosen to be 2400 lines/ mm, this corresponds to a sensitivity of 0.417 µk per fringe order. When the specimen is deformed the interference pattern (moire' fringes) is formed and collected by a video camera connected to a PC-based digital image processor. Analysis of the moire pattern results in full field displacement.
Grain Boundaries in High Thermal Conductivity Aluminum Nitride.
Authors: Mckernan Stuart , Norton M. Grant , Carter C. Barry 
Published: March 2011

ABSTRACTThe benefits of AIN as a substrate material for the electronics packaging industry appear to be limited by the deleterious effects of boundaries in the polycrystalline material. Some observations on different types of boundary in AIN using several complementary techniques are reported.
Thermal Conductivity of Aluminum Nitride Thin Films
Authors: Shaw-Klein L. J. , Burns S. J. , Jacobs S. D. 
Published: March 2011

ABSTRACTAnomalously low laser damage resistance thresholds have been observed in many thin film systems. Thermal conductivity values well below bulk have been suggested as a possible cause. A series of reactively sputtered AIN films were deposited on fused quartz and sapphire substrates. Their thermal conductivities were measured using the thermal comparator technique. Important factors contributing to the apparently large thermal resistance in the AIN films include film surfaces, small grain size, and high oxygen concentration. Preferred orientation and columnar morphology also affect film conductivity. Film microstructures were observed by transmission electron microscopy, and correlated with measured values of thermal conductivity.
Interactions of Copper with Interlayer Dielectrics and Adhesion Promoters / Diffusion Barriers.
Authors: Arcot B. , Shy Y.T. , Murarka S.P. , Shepard C. , Lanford W.A. 
Published: March 2011

ABSTRACTCopper with its high conductivity, specific heat and melting point (compared to Al), is being investigated as the interconnection metal for applications both on and off the chip. Such interconnection wirings will be seperated by the dielectric layers which could be either polymers or inorganic oxides like SiO2. In such applications an adhesion promoter, which may also work as a diffusion barrier, maybe used between the dielectric and the metal film. An investigation of the diffusion and interaction of Copper with such dielectrics and insulators has been carried out in the temperature range of 200 – 500 ºC. Specifically, interactions of Copper with SiO2'P—glass, Polyimidesiloxane and Magnesium are investigated. Results of these studies will be presented and discussed.
Measurement of Mechanical Bulk- and Interfaceproperties of Thin Polymeric Films
Authors: Kim Kyung-Suk 
Published: March 2011

ABSTRACTTheoretical and experimental studies on the measurement of the mechanical constitutive relation and the interfacial strength for thin polymeric film structures are presented. For the measurement of the constitutive relation, a new innovative testing technique based on the J-integral concept is introduced. This method measures the stressstrain relationship in the thickness direction, while the stress-strain relationship in the lateral direction can be measured with conventional techniques. For the measurement of interface strength the cut test and the ball rolling test were used to construct the failure criteria, based on the interface fracture mechanics concept. The interface between polyimide and glass (SiO2) has been tested and analyzed in detail. This shows that the toughness of the PMDA-ODA polyimide/glass interface was measured as 2.2 J/m2 in pure opening mode and as 15 J/m2 for pure sliding mode. It was also observed that the PMDA-ODA/SiO2 interface toughness is insensitive to temperature variations in the range of 20ºC — 250ºC.
Low Temperature Deposition of High Dielectric Constant Thin Films for Decoupling Capacitor Applications
Authors: Li P. , Gittleman B. , Lu T.-M. 
Published: March 2011

ABSTRACTHigh dielectric constant thin films for packaging applications were studied. Compared with polycrystalline or epitaxial ferroelectric thin films amorphous ferroelectric films are a promising alternative because of their ease of processing and low leakage current. Reactive Partially Ionized Beam deposition (RPIB) offers a new approach to deposit high dielectric constant films at a low substrate temperature. As an example, the growth of amorphous BaTiOs thin films using RPIB deposition is described. The films were characterized in terms of dielectric constant and leakage current. The annealing effects on the film properties are also discussed.
The Effect of Sputtering Conditions on Submicron Contact Filling Using Laser Planarization
Authors: Yu C. , Doan T.T. , Kim S. , Sandhu G.S. 
Published: March 2011

ABSTRACTThe effect of sputtering conditions of Al alloy films on the ability to fill submicron contact/vias by laser planarization has been investigated. A significant improvement in the process window (complete contact filling to optical ablation) has been observed by using high temperature and/or bias sputtering. In general, the process window increased with the increasing deposition temperature and substrate bias voltage. For 0.9 μm diameter contacts of aspect ratio ∼ 1, the process window for contact filling by AlSi(l%)Cu(0.5%) increased from 5% for standard deposition parameters to a record high 30% by using the optimized sputtering conditions.
Effect of Oxygen Exposure and Deposition Environment on Thermal Stability of Ta Barriers To Cu Penetration.
Authors: Bojarczuk N.A. , Clevenger L.A. , Holloway K. , Harper J.M.E. , Cabral C. , Schad R.G. , Stolt L. 
Published: March 2011

ABSTRACTThe effect of deposition pressure and controlled oxygen dosing on the diffusion barrier performance of thin film Ta to Cu penetration was investigated. In-situ resistivity, Auger compositional profiling, scanning electron microscopy and cross-sectional transmission electron microscopy were used to determine the electrical, chemical and structural changes that occur in Cu/Ta bilayers on Si upon heating. A 20 nm Ta barrier allowed the penetration of Cu at temperatures ranging from 320 to 630°C depending on processing conditions. Barrier failure temperature is dependent upon the deposition pressure and oxygen contamination at the Ta/Cu interface. This indicates the importance of understanding how deposition conditions affect diffusion barrier performance.
Application of Superplasticity in Solder Joints
Authors: Shine M. C. , Seyyedi J. , Massingill T. , Mei Z. , Morris J. W. 
Published: March 2011

ABSTRACTThe lifetime of non-compliant eutectic solder joints was improved by an order magnitude by rapid quenching. The quenching produces a fine equiaxed superplastic grain structure which lowers the stresses in the solder joints for the fatigue cycle strain range. Similarly, compliant J Bend and Gull wing joints, which last thousands of cycles, operate at lower stresses where superplastic deformation predominates.
Flip-Chip Bump Bonding Reliability and Process Improvement
Authors: Koh Wei H. , Mayemura S. , Kuipers W. 
Published: March 2011

ABSTRACTLong term reliability of flip-chip bump bonding for application in infrared detector interconnection is investigated. The effectiveness of a thin film nickel as diffusion barrier for reducing indium-gold intermetallic formation is studied by accelerated life test and destructive physical analysis. A new interconnect structure replacing the conventional bump-to-bump configuration is described.
MOCVD of GaN Using Diethylgalliumazide and Ammonia
Authors: Ho Kwok-L. , Jensen Klavs F. , Hwang Jen-W. , Evans John F. , Gladfelter Wayne L. 
Published: March 2011

ABSTRACTGaN thin films have been deposited on Si and sapphire substrates by metalorganic chemical vapor deposition (MOCVD) using diethylgalliumazide and ammonia. Films were grown in the temperature range of 500-750°C. Growth rates were monitored in situ using laser interferometry. The addition of ammonia enhanced the growth rate significantly. At high temperatures, gas-phase depletion of the precursor reduced the growth rate of GaN. Films grown on (0001)-oriented sapphire substrates at temperatures above 650°C were highly textured with smooth surface morphology. Optical and electrical properties of the films are discussed and compared to those of films grown using conventional Ga and N sources.
The Use of Tris(Trimethylsilyl)Arsine to Deposit GaAs by OMCVD
Authors: Berry Alan D. , Purdy Andrew P. , Wells Richard L. , Pasterczyk James W. , Johansen James D. , Pitt Colin C. 
Published: March 2011

ABSTRACTChemical vapor deposition experiments using (Me3Si)3As with either GaCl3 or Me3Ga at ambient pressure have produced films of GaAs on Si and semi-conducting GaAs substrates. The films have been characterized by X-ray diffraction and Auger electron spectroscopy, and each have small amounts of C and O impurities. No desired films were deposited from (C6F5)3GaAs(SiMe3)3 at 500°C and low pressures.
A Comparison of Arsine and Tertiarybutylarsine as Precursors for the Selective Epitaxial Growth of GaAs and AlGaAs
Authors: Smith F.T.J. 
Published: March 2011

ABSTRACTWe have investigated the use of tertiarybutylarsine (tBAs) as an As source in the surface-selective growth of GaAs and AlGaAs by low-pressure OMVPE. Deposition was carried out onto GaAs substrates partly masked with SiNx. Triethylgallium (TEGa) and trimethylaluminum (TMAl) were used as precursors along with either arsine or tBAs. Growth pressures were in the range 0.3 to 3.0 Torr. The usual trends of decreasing deposition on the mask with increasing temperature, decreasing group V/III ratio, and decreasing pressure were observed. At very low group V/III ratios, for either As precursor, single crystal material with a pitted surface was obtained. A reduction in the nucleation of polycrystalline material on the mask was observed when tBAs was used in place of AsH3.
High Performance 0.5 and 0.25 μm Gate GaAs Mesfet Grown by MOCVD Using Tertiarybutylarsine
Authors: Sundaram V.S. , Mao B.-Y. , Zurek S.J. , Levy H.M. , Lee G.Y. , Fraas L.M. 
Published: March 2011

ABSTRACTUsing tertiarybutylarsine and trimethylgallium a GaAs MESFET structure was grown and fabricated into half and quarter micron devices. The typical transconductance and unity current gain frequency (ft) for the half micron device were 360 mS/mm and 24 GHZ respectvely. The corresponding numbers for the quarter micron devices were 510 mS/mm and 55 GHZ respectively.
Decomposition Mechanisms of Antimony Source Compounds for Organometallic Vapor-Phase Epitaxy
Authors: Larsen Cory A. , Gedridge Robert W. , Li Shin Hwa , Stringfellow Gerald B. 
Published: March 2011

ABSTRACTThe decompositions of tertiary stibines (R3Sb, R = methyl, vinyl, isopropyl) were studied in an atmospheric pressure flow tube reactor, using D2 and He as carrier gases. D2 was used to isotopically label the byproducts in order to elucidate the pyrolysis mechanism. The exhaust products were analyzed by a time-of-flight mass spectrometer. The decomposition of these tertiary stibines in the presence of group Ill precursors was studied in order to simulate the conditions of organometallic vapor phase epitaxial growth. A comparison between the pyrolysis temperatures, decomposition mechanisms, and surface area effects of these Sb source compounds is presented.
Polychalcogenide Complexes as Low Temperature Precursors for Quantum Size and Bulk Binary and Ternary Semiconductors
Authors: Dhingra Sandeep , Kim Kang-Woo , Kanatzidis Mercouri G. 
Published: March 2011

ABSTRACTWe report the utility of \Cd(Se4)2]2-, \Cu4Se12]2- and \In3Se15]3- as convenient low temperature precursors to semiconducting CdSe and CuInSe2. DMF and DMSO solutions of these complexes react with Se-abstracting reagents such as CN- and n-(Bu3)P to yield the corresponding binary solids at 155 °C or less. Appropriate stoichiometric mixtures of \Cu4Se12]2- and \In3Se15]3- react to give CuInSe2. The semiconducting solids were characterized with UV/vis spectroscopic, X-ray crystallographic and electron (scanning and transmission) microscopic techniques. The particle size of these materials can range from the quantum-size regime to the bulk regime, depending on the reaction conditions, metal precursor complex and Se-abstracting reagent used.