bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymer Coating of Glass Microballoons Levitated in a Focused Acoustic Field
Authors: Young Ainslie T. , Lee Mark C. , Feng I-An , Elleman Daniel D. , Wang Taylor G. 
Published: March 2011

ABSTRACTInertial confinement fusion (ICF) glass microballoons (GMBs) levitated in a focusing radiator acoustic device can be coated with liquid materials by deploying the liquid into the levitation field with a stepped-horn atomizer. The GMB can be forced to the center of the coating liquid with a strong acoustically generated centering force. Water solutions of organic polymers, uv-curable liquid organic monomers, and paraffin waxes have been used to prepare solid coatings on the surface of GMBs using this technique.
Crystal Nucleation in Pd-Si Alloys
Authors: Drehman A.J. , Turnbull D. 
Published: March 2011

ABSTRACTWe report here a study of the crystal phase nucleation in undercooled droplets of Pd-Si alloys with composition near the Pd84.5Si15.5 eutectic composition. Molten droplets are released at the top of a drop tube and solidify (to either a crystalline or glassy state) during descent. This provides a containerless (and nearly gravity free) environment so that nucleation due to container walls or vibrations is eliminated. We found that crystallization, due to homogeneous nucleation, is bypassed in droplets of 1 mm diameter when cooled at 760 K/sec. From this an upper limit of the homogeneous nucleation rate is estimated. Results are compared with our previously published study of nucleation in 0.06mm to 0.33 mm diameter droplets, which indicated that nucleation results from heterogeneous surface nucleation and that the number of these nuclei is dependent on the atmosphere in the drop tube.
Variation in the Properties of Superlattices with Band Offsets
Authors: McGill T. C. , Miles R. H. , Wu G. Y. , Watson T. J. 
Published: March 2011

ABSTRACTThe implications for recent reports of large valence band offsets the HgTe-CdTe heterojunction are examined. The variation of the band gap and effective mass for transport normal to the layers in the superlattice is examined in detail.
Identification and Sources of Impurities in InGaAs Grown by Liquid Phase Epitaxy
Authors: Knight D. G. , Miner C. J. , Majeed A. 
Published: March 2011

ABSTRACTHigh purity In.53 Ga.47 As and InP with carrier concentrations [ND–NA] < 5×1015 cm−3 has been grown by the LPE technique on both n-type and semi-insulating substrates to detect and identify trace donor and acceptor impurities. Acceptor impurities have been detected in low temperature photoluminescence spectra where LPE melt baking and growth programs indicate a melt origin for two of these species, one of which is zinc. Data from semiconductor profiles provides evidence for sulfur and tin donor impurities, which comes from the rinse melt used to etch back substrates doped with the respective contaminants. Silicon and sulfur contaminants have been detected by SIMS measurements; and may arise not only from the indium and III-V materials, but also the graphite boat used to grow the epilayers. Volatile sulfur-containing compounds have been detected during high temperature bake-out of high purity graphite boats.
Infrared Reflectance Characterization of a GaAs-AlAs Superlattice
Authors: Zavada J. M. , Hubler G. K. , Jenkinson H. A. , Laidig W. D. 
Published: March 2011

ABSTRACTThe optical properties of a GaAs-AlAs superlattice have been examined using the non-destructive technique of infrared reflectance spectroscopy. Through this technique, the absorption edge, the effective superlattice refractive index, the thickness, and the optical grading of the superlattice-substrate were determined. Location of the absorption edge was made from the reflectance spectrum and showed general agreement with photoluminescence measurements. A more detailed analysis of the infrared spectra indicated the presence of a transition region between the substrate and the superlattice. Based on a non-linear least squares method for fitting the experimental data, a dispersion relation for the dielectric function was obtained. This dielectric function yielded a value for the superlattice refractive index that was lower than that of the corresponding, homogeneous, AlGaAs alloy film for wavelengths between 1.0 and 2.5 micrometers.
Surface Recombination Measurements in HgCdTe by Optical Modulation Frequency Response
Authors: Mroczkowski J. A. , Lesondak E. , Resler D. 
Published: March 2011

ABSTRACTThe frequency response in the modulation of the excess electron concentration, produced by a modulated photogenerating pump beam, is used to determine bulk life-time and the surface or interface recombination velocity. The depth-wise integrated excess electron concentration is contactlessly monitored by the proportional absorption/ transmission modulation of a second probe beam. Using this approach over the 20 kHz to 3 MHz frequency range recombination velocities up to 104 cm/sec have been measured in n-type epitaxial HgCdTe films.
Orientation Effects on the Heteroepitaxial Growth of CdxHg1−xTe on to CdTe and GaAs
Authors: Giess J , Gough J S , Irvine S J C , Mullin J B , Blackmore G W 
Published: March 2011

ABSTRACTFor MOVPE growth of CdTe on to (100) GaAs the orientation of the epitaxial layer is dependent on a combination of the growth conditions and substrate treatment prior to growth, (100) being the preferred orientation. (111) oriented CdTe layers can be grown on to (111) GaAs substrates. The effect of orientation on the choice of buffer composition, electrical properties and the extent of Ga diffusion from the substrate is discussed. Epitaxial CMT layers grown on to suitably buffered GaAs substrates are compared to similar layers grown on to CdTe substrates.
Modeling of HgCdTe Heterojunction Devices
Authors: Zanio Ken , Hay Ken 
Published: March 2011

ABSTRACTA model for generating the composition and doping profiles from growth and diffusion parameters was developed for heterostructure devices. Poisson's equation was applied to these structures to predict barriers in the conduction band to minority carrier flow for long wavelength HgCdTe infrared detectors prepared by LPE techniques. Spectral response and quantum efficiency measurements illustrate the presence of these barriers and support the use of this model in predicting barrier formation.
HgTe-CdTe Superlattices Grown by Photo-MOCVD
Authors: Ahlgren William L. , James J. B. , Ruth R. P. , Patten E. A. , Staudenmann J.-L. 
Published: March 2011

ABSTRACTHgTe-CdTe superlattices have been grown, for the first time, by photoassisted MOCVD. The substrate temperature was 182°C. Superlattices were obtained despite low growth rates requiring long growth times (∼10 hours). Interdiffusion during growth may be slowed down by growing under saturated Hg vapor to minimize cation-vacancy formation. The nominal superlattice structures were 70Å HgTe-30Å CdTe, 40Å HgTe-40Å CdTe, and similar. Actual superlattice structures were verified by cross-sectional TEM and diffractometer x-ray diffraction patterns. The x-ray diffraction patterns showed satellite peaks up to third order. The actual structures had HgTe layers ∼20% thicker than the nominal (target) values. A grid-like array of dislocations at the substrate-epilayer interface, suggesting operation of a dislocation-blocking mechanism, was observed. Deficiencies in the superlattice growths include a low growth rate, nonuniform layers, high dislocation density (∼108 cm−2 in best layers), and high n-type carrier concentration (∼1018 cm−3 with mobilities up to 3.5 × 104 cm2 V−1 s−1 in the best layer) which may reflect the presence of donor impurities in the material.
Limited Reaction Processing: Silicon and III–V Materials
Authors: Gibbons James F. , Reynolds S. , Gronet C. , Vook D. , King C. , Opyd W. , Wilson S. , Nauka C. , Reid G. , Hull R. 
Published: March 2011

ABSTRACTLimited Reaction Processing (LRP) is a new technique which combines Rapid Thermal Processing (RTP) and Chemical Vapor Deposition (CVD). The added temperature control provided in rapid thermal processing enables the use of substrate temperature as a reaction switch. In addition, rapid thermal technology has been shown to provide other advantages for chemical vapor deposition of Si and III–V materials. Results are presented for group IV materials including epitaxial Si, SiGe alloys, SiO2 , and polysilicon. MOSFETs have been demonstrated and sensitive tests of interface quality are presented, paving the way for future bipolar transistor fabrication. III–V materials such as GaAs, AlGaAs, InGaAs have been grown. GaAs electron mobilities are the best reported for material grown using trimethylarsenic. As-ambient rapid thermal anneals of GaAs have also been performed.
Diffusion of Zn into Gaas 0.6 P0.4:Te From Zn-Doped Oxide Films By Rapid Thermal Processing
Authors: Usami A. , Tokuda Y. , Shiraki H. , Ueda H. , Wada T. , Kan H. , Murakami T. 
Published: March 2011

ABSTRACTRapid thermal processing using halogen lamps was applied to the diffusion of Zn into GaAs0.6 P0.4:Te from Zn-doped oxide films. The Zn diffusion coefficient of the rapid thermal diffused (RTD) samples at 800°C for 6 s was about two orders of magnitude higher than that of the conventional furnace diffused samples at 800°C for 60 min. The enhanced diffusion of Zn by RTD may be ascribed to the stress field due to the difference in the thermal expansion coefficient between the doped oxide films and GaAs0.6P0.4 materials, and due to the temperature gradient in GaAs0.6P0 4 materials. The Zn diffusion coefficient at Zn concentration of 1.0 × l018 cm−3 was 3.6 × 10−11, 3.1 × 10−11 and 5.0 × 10−12 cm2 /s for the RTD samples at 950°C for 6 s from Zn-, (Zn,Ga)- and (Zn,P)-doped oxide films, respectively. This suggests that Zn diffusibility was controlled by the P in the doped oxide films.
Si implants into Preamorphised GaAs
Authors: Gwilliam R. , Deol R.S. , Blunt R. , Sealy B.J. 
Published: March 2011

ABSTRACTDual implants of (P+ + Si+) through thin Si3N4, layers have been studied. The phosphorus dose has a marked effect on the electrical properties of 6 × 1012 Si+ cm−2. Optimum electrical activation occurred at a phosphorus dose well below that required to produce an amorphous layer and depended on whether a furnace or a rapid thermal anneal was performed. Good control over the tail of the electron concentration profile was obtained for doses of phosphorus in the range 6 × 1012 to 1 × 1014 ions cm−2.
Carrier and Atomic Distributions in Si Implanted and Rapid Thermally Annealed InP ; Influence of Dual Implants of As or P
Authors: DUIIAMEL Nicole , DESCOUTS Brigitte , KRAUZ Philippe , RAO Krishna , DANGLA Jean , HENOC Pierre 
Published: March 2011

ABSTRACTRapid thermal anneal (R.T.A.) by halogen lamps has been carried out to activate Si29 implants in semi-insulating InP substrates with the aim of realizing good contact areas at low depth (0.1 μm). To better understand the electrical behaviour of Si observed in these conditions, and to try to increase the electrical activity we performed dual implantations (As + Si or P + Si). The crystallographic disorder remaining after anneal and its influence on the electrical properties are discussed. The uniformity of activation has been evaluated by Hall effect and specific contact resistivity cartographies both for mono-implantations and for dual implantations.
Epitaxial Alignment of as Implanted Polysilicon Emitters
Authors: Hoyt J.L. , Crabbé E.F. , Gibbons J.F. , Pease R.F.W. 
Published: March 2011

ABSTRACTWe demonstrate a clear advantage for high-temperature, short time annealing to induce intentional, complete epitaxial alignment of arsenic implanted, 0.5 μm-thick polysilicon films on (100) silicon, while minimizing arsenic outdiffusion into the substrate. Using MeV ion channeling and cross-sectional electron microscopy, epitaxial alignment was studied in the 1050-1150 °C temperature range, for arsenic doping concentrations between 1 and 10 × 1020 cm−3. The alignment efficiency increases dramatically with chemical arsenic concentration in this range. An arsenic concentration of 1020 cm−3 yields alignment behavior which proceeds from the polysilicon/single-crystal interface. Between 1 and 5 × 1020 cm×3, the random grain growth can exceed the rate of alignment, and large grain, highly oriented polycrystalline films can result from the RTA. For 0.5 μm-thick polysilicon films with an average doping of 1021 cm×3, the rate of achievement of a high degree of epitaxial alignment exceeds the rate of arsenic penetration into the substrate at temperatures ≥ 1150 °C.Bipolar transistors with 0.5 μm-thick emitter contacts and polysilicon dopings of 5 and 10 × 1020 cm×3 show less variation in base current when subjected to RTA (T ≥ 1100 °C) compared to devices annealed in a furnace in the 900 to 1000 °C range, while retaining the advantage over metal contacts.
A Study of Grain Growth in Ion Irradiated Co-Cr Alloy Films
Authors: Li J. , Liu B. X. , Li H. D. 
Published: March 2011

ABSTRACTExperiments concerning the behavior of grain size in Co80Cr20 alloy thin films upon ion irradiation were conducted. The alloy films of 80 nm thick were prepared by magnetron sputtering on cleaved NaCl crystal substrates, and then irradiated by 300 keV argon or xenon ions to a wide range of doses. The irradiated samples, before and after annealing, were examined by transmission electron microscope (TEM). It was found that the initial grain size with the dimension of 20 nm remained unchanged when the dose was less than 1×1016Ar/cm2, but rapidly reduced to the scale of 5 nm at a dose of 5×1016Ar/cm2. It is thought that this is due to a polymorphic transformation of an HCP to a BCC structure in the alloy films. After 30 min. anneals at 200° C, it was observed that the grain growth rate was a function of ion dose, and that there exists a critical fluence yielding a maximum grain growth rate. The possible mechanisms for the observations in this study are discussed.
Ion-Beam-Induced Plastic Deformation of Amorphous Materials
Authors: Klaumünzer S. , Ming-Dong Hou , Schumacher G. , Chang-Lin Li 
Published: March 2011

ABSTRACTAt temperatures far below the glass transition temperature metallic glasses undergo plastic deformation during irradiation with a beam of fast heavy ions at energies at which electronic stopping is the dominant deceleration mechanism. This plastic deformation causes irreversible anisotropic changes in sample dimensions. Various (Fe,Co,Ni)∼8O(B,Si)∼20 glasses and the crystalline alloys Ni80Cr20 and Fe70Cr25A15 are examin? 9 for their susceptibility to this effect by irradiation below 50 K with 129Xe ions at 2.8 MeV/u. The data suggest that the excess free volume of an amorphous material is an essential parameter for the magnitude of ion-beam-induced plastic deformation.
Ion Mixing of Near-Noble Transition Metal Films on Evaporated and Large-Grained Aluminum Substrates
Authors: Ma E. , Zhao X.-A. , Nicolet M-A. 
Published: March 2011

ABSTRACTIon mixing experiments using Xe ions at temperatures ranging from 77K to about 450K were conducted on Al/Ni and Al/Pt couples. Evaporated polycrystalline Al films and large-grained Al crystals were used as substrates. Xenon irradiation of Al/Pt bilayers achieves considerable intermixing and a temperature dependence is observed. Only moderate interfacial mixing with little temperature dependence is observed in Al/Ni bilayers. The mixing efficiency of Al/Ni is consistent with the phenomenological model of thermal spike mixing, and so is the absence of a pronounced temperature dependence below 450K. No significant difference is noted in ion mixing of evaporated and large-grained Al substrates. In contrast to ion mixing, Al/Pt and Al/Ni samples behave similarly upon thermal annealing and form well-defined compounds. The results are also compared with Si/metal systems, where silicides can be formed readily by low temperature thermal annealing as well as by ion mixing of bilayer samples.
Cross-sectional TEM and corrosion studies of Al and N implanted copper
Authors: Gerritsen E. , Ligthart H. J. , Deenen T. E. G. 
Published: March 2011

ABSTRACTPoly- and single crystalline copper was implanted with aluminium and nitrogen at doses ranging from 1016 to 5 × 1017 at/cm2 and energies of 170 keV. The corrosion resistance of the implanted surfaces was tested by exposure to an H25-containing atmosphere. The amount of copper sulphide formed was measured by chrono potentiometric reduction. The amount of corrosion products was markedly reduced (up to a factor 50) by high dose implantations of aluminium. The microstructure of the implanted copper was examined by Transmission Electron Microscopy of cross-sectioned specimens. A deep damage layer far exceeding the ion range was observed. XTEM-pictures of aluminium implanted copper single crystals of various orientations suggest a channeling mechanism for this deep damage layer. In situ annealing of the specimens in the TEM showed that most of the implantation damage is removed at 600°C except for an array of dislocations at the end of the damage range.
X-Ray Measurements of Lattice Strain in Doped Epitaxial Silicon
Authors: Pogany A. P. , Preuss T. E. 
Published: March 2011

ABSTRACT(100) silicon amorphized by antimony ion implantation was epitaxially regrown by either furnace or pulsed laser annealing. Rocking curves were measured on a double-crystal X-ray diffractometer, and compared with calculations based on a one-dimensional strain profile. For laser annealed samples the strain profile followed that of the antimony (redistributed by surface melting), with a proportionality constant given by the Pauling covalent radius ratio. For furnace annealed samples however the strain was found to be deeper, but of smaller peak magnitude, than that expected from the antimony distribution. This is attributed to formation and movement of defects acting to relax lattice strain. Other X-ray strain measurements on epitaxial silicon containing other dòpants are briefly reviewed.
Implanted Dopant-Defect Interactons in GaAs
Authors: Pearton S. J. , Williams J. S. , Short K. T. , Johnson S. T. , Gibson J. M. , Jacobson D. C. , Poate J. M. , Boerma D. O. 
Published: March 2011

ABSTRACTThe implantation temperature dependence of dopant solubility and electrical activity was investigated for Sn, Cd and Te ions in GaAs. Implantation doses of 5×1012 – 5×1015 cm−2 were performed in the temperature range from LN2 to 400°C, followed by rapid thermal annealing (950°C) or furnace annealing between 650°C and 850°C. Solubilities above 1020 cm−3 were obtained for all of the species, with a peak value of 2.5×1021 cm−3 for Te after 850°C furnace annealing. However essentially no correlation existed between dopant solubility and electrical activity or between electrical activity and the high density of defects remaining after many of the annealing cycles. This emphases the role of fine scale, point defect complexes in controlling the electrical activity of implanted dopants in GaAs.
Epitaxy for Weakly Interacting Systems of Large Misfit
Authors: Dregia S. A. , Wynblatt P. , Bauer C. L. 
Published: March 2011

ABSTRACTA simple but general model is developed which describes the elastic relaxations in a misfitting epitaxial thin film on a rigid substrate. The film is treated as a two-dimensional, elastically anisotropic solid with an arbitrary orientation relationship to the underlying substrate. The periodic elastic displacement field, the misfit energy density, and the elastic energy density of relaxation are derived for relatively weak, periodic film-substrate interactions of a generalized form. The model is tested for a misfitting Ni-(111) monolayer in contact with a rigid Ag-(111) substrate, using computer simulations with the embedded atom method. The predicted displacement field has symmetry 3m and has a magnitude which is in close agreement with that obtained by a fully numerical solution. The dependence of the extent of relaxations on the form of the film-substrate interaction is discussed for the special case of unidirectional misfit.
In-Situ Studies of the MBE Growth of CoSi2 on Si (111) in a UHV Transmission Electron Microscope
Authors: Gibson J. M. , Batstone J. L. , Tung R. T. 
Published: March 2011

ABSTRACTIn-situ observations of the growth of CoSi2 films by Co deposition in an ultrahigh vacuum transmission electron microscope are described. Results include the observation of intermediate epitaxial phases (both hexagonally distorted Co2Si and CoSi) and the observation that pinholes nucleate in CoSi2 films after growth in a metastable layer mode.
In-Situ Ellipsometry and Light Scattering Studies of Substrate Cleaning and Initial Layer Deposition in Low Temperature CVD of Crystalline Si
Authors: Pickering C. , Robbins D. J. , Young I. M. , Glasper J. L. , Johnson M. , Jones R. 
Published: March 2011

ABSTRACTThe first in-situ observations of initial stages of growth during Si vapour-phase homoepitaxy are reported, using the simultaneous measurement of dual-wavelength ellipsometry (364/488nm) and diffuse light scattering (488nm). Effective medium modelling shows that initial growth is nonuniform with pits present in the first 50–200Å of growth which rapidly fill in as growth proceeds. The sizes of the ellipsometric and scattering discontinuities are dependent on the extent of pre-growth roughening associated with oxide removal and finite wavelength effects become important for growth on roughened substrates.
Bonding at the CaF2-on-Si(111) Interface
Authors: Olmsteadt Marjorie A. , Bringans R. D. , Uhrberg R. I. G. , Bachrach R. Z. 
Published: March 2011

ABSTRACTThe bonding at the interface between CaF2 and Si(111) has been investigated using core-level photoemission spectroscopy. The results are discussed in terms of various structural models of the interface. The stable interface has a depletion of fluorine from the interface resulting in strong Si - Ca bonding.
Reactions in OMVPE Growth of InP
Authors: Stringfellow G. B. , Buchan N. I. , Larsen C. A. 
Published: March 2011

ABSTRACTOrganometallic vapor phase epitaxy (OMVPE) has achieved remarkable recent success, becoming the most promising technique for the ultimate production of III/V materials and device structures. Unfortunately, our understanding of the growth process remains primitive. In this paper we report a new technique for tracing the reactions by conducting the epitaxial growth in a D2 ambient using a time-of-flight mass spectrometer to analyze the product molecules. The pyrolysis reactions were studied for PH3, both alone and in the presence of trimethylindium (TMIn), and for TMIn alone and in the presence of PH3. For the reactants alone, the PH3 pyrolysis is completely heterogeneous at the InP surface, while TMIn pyrolyzes homogeneously in the gas phase. For TMIn and PH3 together, the reaction mechanism is entirely different; the pyrolysis temperatures for both PH3 and TMIn are lowered. Since the reaction produces only CH4 molecules, with a complete absence of CH3D at high ratios of PH3 to TMIn, we hypothesize that InP growth is initiated by the direct interaction of TMIn and PH3 molecules, either in the vapor phase at normal growth temperatures or at the InP surface at temperatures as low as 250°C.
Charge Transfer and Surface Reaction in Silicon Vapor Phase Epitaxial Growth
Authors: Ishitani A. , Takada T. , Ohshita Y. , Tanigaki K. 
Published: March 2011

ABSTRACTSilicon vapor phase epitaxial growth with SiH2Cl2 is theoretically studied. The optimized geometries and total energigs of the species, generated from SiH2Cl2, are calculated by using ab initio molecular orbital method. As the intgraction between silicon surface and SiCl2 the charge transfer is considered. Based on the computational result that SiCl2 - has the lower total energy than SiCl2, a new adsorption mechanism, named, charge transfer adsorption, is p~oposed. By using this charge transfer adsorption followed by the surface reaction at the hollow bridge site, the epitaxial growths on the silicon (001), (111), and (110) surfaces are discussed.