bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Technique For Measuring Slurry‐Flow Dynamics During Chemical ‐ Mechanical Polishing
Authors: Coppeta J. , Rogers C. , Philipossian A. , Kaufman F. 
Published: April 2011

AbstractChemical‐Mechanical Polishing (CMP) is one of the fastest growing market segments in the semiconductor equipment industry. One of the critical consumable in CMP is a specialized solution, or slurry, which contains both free abrasives and chemicals acting together to planarize a wafer. These chemically active slurries account for approximately one fifth of the total cost of polishing a wafer. Because of the cost and potential toxicity, there are both financial and environmental pressures to reduce the amount of slurry consumed during the CMP process. To accomplish this in a systematic manner we have developed a technique for quantifying slurry flow patterns during CMP which involves using fluorescent dyes to measure slurry mixing, temperature gradients and slurry aging during the polishing. An aqueous fluorescent solution with matching viscosity is used to model the slurry, a glass window models the wafer and a commercially available polisher provides the polishing pad/table rotating work surface. This talk will focus on the diagnostic technique used to measure the slurry behavior as well as some semi‐quantitative results on both the amount and uniformity of slurry entrained beneath the wafer as a function of pad topography, injection location and pad rotation rates.
MBE Growth of InSb Based Device Structures onto InSb(111)A,(111)B and InGaSb(111)A Substrates
Authors: Johnson A D , Jefferies R , Pryce G J , Beswick J A , Ashley T , Newey J , Elliot C T , Martin T 
Published: April 2011

ABSTRACTWe report on the optimum growth conditions for Molecular Beam Epitaxy (MBE) growth of InSb onto InSb (111)A and (111)B substrates. It was found that for (111)A substrates the optimum epilayer morphology was obtained for growth temperatures above 385°C and with a Sb:In ratio of 1.5:1. In contrast, for the (111)B surface, best morphology was found for growth temperatures above 385°C but with V:III ratio of ∼7.0:1. In both cases the dopant incorporation was found to be the same as the (100) surface and did not particularly depend either on V:III ratio or substrate temperature. We also describe the device characteristics of InAlSb light emitting diodes (LEDs) grown lattice matched onto ternary InGaSb(111)A substrates using the optimized growth conditions obtained.
In Situ Spectroscopic Ellipsometry for Monitoring and Control of HgCdTe Heterostructures Grown by Molecular Beam Epitaxy
Authors: Almeida L. A. , Bevan M. J. , Duncan W. M. , Shih H. D. 
Published: April 2011

ABSTRACTA major advantage of vapor phase epitaxial growth techniques is their flexibility to produce Hg1−xCdxTe layers with difFerent compositions from one run to the next, as well as the flexibility to produce compositional heterostructures of Hg1−xCdxTe in one process step. To take full advantage of this flexibility, reliable, automated control must be introduced. To this end, a phase-modulated spectroscopie ellipsometer (SE) has been implemented for use as a contactless wafer state sensor. In this work SE was used to monitor in real-time the stoichiometry of epitaxial Hg1–4CdxTe during growth by molecular beam epitaxy (MBE). SE has provided valuable information about the MBE growth process, by revealing even small fluctuations in x (± 0.002). In particular, SE has measured the compositional profiles of both LWIR/MWIR and MWIR/LWIR interfaces. Distinct profiles were revealed for interfaces created by abrupt changes in the CdTe effusion cell set-point and for interfaces created by ramping the cell temperature linearly. Ramping results in a smoothly graded interface, whose thickness may be pre-determined, though typically 2000 Å. An abrupt set-point change results in a sharper transition (∼300 Å) followed by oscillations in composition associated with the settling time of the cell (∼1500 Å). The thickness of a CdTe passivation layer grown on a LWTR layer was determined. The current status of the SE will be reported through other illustrative examples which demonstrate its utility as a diagnostic tool and as a sensor for realtime, feed-back control of the MBE process.
HgCdTe(211)B Grown on CdTe(211)B/ZnTe(211)B/Si(211) by MBE
Authors: Rujirawat S. , Wijewarnasuriya P. S. , Chen Y. P. , Aqariden F. , Sivananthan S. 
Published: April 2011

ABSTRACTWe present preliminary results on HgCdTe(211)B layers grown on CdTe(211)B/ZnTe(211)B/Si substrates by molecular beam epitaxy. As-grown layers show excellent n-type characteristics as measured by Hall effect. Hall mibilities higher than 1×10 cm2/v-s have been measured at 40K for Cd composition ∼24% with doping level ∼ 3×1015 cm−3. Obtained RHEED patterns during the growth shows very smooth surface morphology.
Raman Scattering Study of H2O2-Etched Zn0.1Cd0.9Te Surfaces
Authors: Rai Brajesh K. , Katiyar R. S. , Chen K. -T. , Chen H. , Burger A. 
Published: April 2011

ABSTRACTRaman study of as-grown and H2O2-etched surfaces of Zn0.1Cd0.9 Te single crystal has been performed. A distribution of Te precipitates on the surface of as-grown ZCT, which increases after etching, has been encountered. With high irradiation powers, due to the oxidation of the surfaces, new bands of TeO32− are evolved. A downward shift in the peak position, as well as a halfwidth broadening, of all Raman modes has been observed with increasing laser power. The phenomenon, due to the formation of insulating oxide of tellurium in a dispersion of Te precipitates and vice-versa, has been attributed to the quantum confinement of phonons.
IR Sources and Modulators Based on InAs/GaSb/AlSb-Family Quantum Wells
Authors: Meyer J. R. , Felix C. L. , Malin J. I. , Vurgaftman I. , Lin C.-H. , Yang R. Q. , Pei S.-S. , Ram-Mohan L. R. 
Published: April 2011

ABSTRACTWe review recent applications of wavefunction engineering to the design of antimonide quantum heterostructures with favorable properties for infrared devices. Examples include electro-optical and all-optical modulators based on Г-L intervalley transfer, type-II quantum well lasers with enhanced gain per injected carrier, and type-II interband cascade lasers predicted to combine low thresholds and high output powers.
Melt Growth of ZnGeP2: Homogeneity Range and Thermochemical Properties
Authors: Fiechter S. , Castleberry R. H. , Angelov M. , Bachmann K. J. 
Published: April 2011

ABSTRACTZnGeP2 crystallized from the melt via horizontal gradient freezing shows the tendency to decompose into Ge and GeP when the equilibrium vapor pressure is not exactly controlled during the entire crystallization process. Using differential thermal analysis (DTA) it was found that ZnGeP2 has a truly congruent melting point of 1311 K. Adding small amounts of the elements and binaries in the ternary system Zn-Ge-P to stoichiometric ZnGeP2 a significant deflection of the liquidus curve was observed at the melting point of ZnGeP2- From DTA, X-ray diffractometry (XRD), photoluminescence (PL), transmission and conductivity measurements it was concluded that the melt grown material was highly compensated. The presence of a broad acceptor and donor band in the band gap could be associated with phosphorous and zinc point defects in the crystal lattice. It is assumed that the defect concentrations are of the order 1019 cm−3.
Electron Paramagnetic Resonance and Photoluminescence Studies of Point Defects in Zinc Germanium Phosphide (ZnGeP2)
Authors: Setzler S. D. , Halliburton L. E. , Giles N. C. , Schunemann P. G. , Pollak T. M. 
Published: April 2011

ABSTRACTElectron paramagnetic resonance (EPR) has been used to monitor native defects, both acceptors and donors, in ZnGeP2 crystals grown by the horizontal gradient freeze technique. These active centers include singly ionized zinc vacancies (Vzn-), neutral phosphorus vacancies (VP0), and neutral phosphorus antisite defects (PGe0). The concentration of Vzn− acceptors correlates with the near-infrared optical absorption present in all ZnGeP2 crystals. A photoluminescence band near 1.4 eV is shown to be polarized and is attributed to donor-acceptor-pair (DAP) recombination. Preliminary time-decay measurements support this assignment. Observation of the EPR spectrum of Mn2+ is also reported.
Photoluminescence Study of p-ZnGeP2 Crystals
Authors: Rud Yurri V. , Yu Vasilii , Ohmer M. C. , Shunemann P. G. 
Published: April 2011

ABSTRACTPhotoluminescence (PL) steady-state spectra of p-ZnGeP2 (ZGP) single crystals grown by high- and low-temperature directed crystallization have been investigated. It is determined that the long-wavelength component PL with a maximum in the interval 1.2–1.5 eV for different crystals quenched in the temperature range 77–300 K. The long-wavelength component PL are due to donor-acceptor pair transitions. At room temperature the short-wavelength PL with a maximum near 1.85 eV becomes the determining component. The nature of this band discussed. The use of low-temperature directed crystallization reduces the concentration of lattice defects in ZGP single crystals and opens up the new possibilities for increasing the conversion efficiencies of nonlinear devices.
Modeling of Be Diffusion in InGaAs Epitaxial Structures
Authors: Gautier S. , Koumetz S. , Marcon J. , Ketata K. , Ketata M. , Launay P. 
Published: April 2011

ABSTRACTThe subject of this work is the simulation of Be diffusion during post-growth Rapid Thermal Annealing (RTA) of InGaAs epitaxial layers grown by Chemical Beam Epitaxy (CBE). This diffusion may occur during thermal treatments of InGaAs/InP Heterojunction Bipolar Transistors (HBT's), which contributes to limit the frequency performances of these devices. In order to characterize the Be depth profiles, Secondary Ion Mass Spectrometry (SIMS) has been used. The concentration dependent diffusivity has been covered to perform an improved data fitting of Be diffusion profiles. In a first step, the solid state diffusion mechanisms have been developed, including the Substitutional-Interstitial Diffusion (SID) and, in particular, Kick-out mechanism. To explain the observed concentration profiles and related diffusion mechanisms, a Generalized Substitutional-Interstitial Diffusion model is proposed. A simultaneous diffusion by Dissociative and Kick-out mechanisms is suggested. Good agreements between experimental depth profiles and simulated curves have been obtained.
Room Temperature led's for the MID-Infrared Based on in(AS,SB) Strained Layer Superlattices
Authors: Phillips C. C. , Tang P. J. P. , Puliin M. J. , Hardaway H. R. , Chung S. J. , Yuen W. T. , Stradling R. A. , Li Y. B. , Hart L. 
Published: April 2011

ABSTRACTArsenic-rich InAs/InAs1−x Sbx strained-layer superlattices (SLS's) are studied in time-resolved optical, and CW magneto-optical spectroscopies. A pronounced type-II offset, with electrons confined to the alloy layers, is found. High radiative efficiencies at wavelengths well into the mid-IR, and the suppression of Auger recombination yield LED's operating at 3–10 μm. Present room temperature powers are ∼30 μW, probably limited by inadequate carrier confinement.
Theoretical Performance of MID-IR Broken-Gap Superlattice Quantum Well Lasers
Authors: Flatté Michael E. , Grein C. H. , Olesberg J. T. , Boggess T. F. 
Published: April 2011

ABSTRACTWe will present calculations of the ideal performance of mid-infrared InAs/InGaSb superlattice quantum well lasers. For these systems several periods of an InAs/InGaSb type-II superlattice are grown in quantum wells. Calculations of the non-radiative and radiative lifetimes of the carriers utilize the full non-parabolic band structure and momentum-dependent matrix elements calculated from a semi-empirical multilayer K · P theory. From these lifetimes, threshold current densities have been evaluated for laser structures. We find serious problems with the hole and electron confinement in the superlattice quantum wells grown to date, and propose a four-layer superlattice structure which corrects these problems.
Low-Loss, Broadened-Waveguide, High-Power 2-μm AlGaAsSb/InGaAsSb/GaSb Separate Confinement Quantum-Well Lasers
Authors: Menna R. J. , Garbuzov D. Z. , Martinelli R. U. , Lee H. , York P. K. , Connolly J. C. , Narayan S. Y. 
Published: April 2011

ABSTRACT(Al, In)GaAsSb/GaSb MQW lasers with a broadened waveguide have been used to fabricate 2-μm diode lasers with CW output power of 1.2 W. 2-μm linear arrays have output powers of 11 W and an efficiency of 0.13 W/A.
New Low Temperature Phases of Tungsten Oxynitride Stabilized by Doping with Fe, Co, and Ni
Authors: Chen F. , Aitken J. , Parasher S. 
Published: April 2011

AbstractSeveral low temperature tungsten-containing oxynitride phases were isolated and stabilized by doping with Fe, Co, and Ni. These Phases have the rocksalt structure and form around 420 °C by reacting MWO4 (M=Fe, Co, Ni) with dry ammonia. They served as intermediates in the formation of the hexagonal ternary nitrides (MWN2). X-ray powder diffraction analyses of these phases indicate that W0.62(NO) could be the parent structure type in each case. The incorporation of group VIIIB elements in the W0.62(NO) structure may play an important role in the formation and stabilization of these low temperature phases.
A Priori Prediction of Crystal Structures
Authors: Brown I. D. 
Published: April 2011

AbstractThe arrangement of atoms in a crystal is determined by two factors, the bonding preferences of individual atoms (giving rise to short range order), and the translational symmetry operations of the space group (giving rise to long range order). Chemical rules can be used to determine which atoms are bonded, and hence the maximum possible symmetry of the formula unit. Space group theory is then used to find the space groups that are compatible with this symmetry. In favourable cases, using the principle of maximum symmetry, the structure can be completely determined, but in all cases the analysis yields insights into the restrictions that determine what crystal structures might be possible.
Effect of Chemistry and Structure on Voltage of Li Intercalation Oxides
Authors: Aydinol M. K. , Ceder G. , Kohan A. F. 
Published: April 2011

AbstractWith the aid of today's powerful computers, quantum mechanical methods are becoming accurate enough to determine the properties of materials before going into laborious and expensive synthesis processes. These “computer experiments” do not require any input other than the atomic numbers of the constituent species. In addition, they allow full control over the “experimental” parameters. In this way the effect of any parameter on the materials properties can be investigated, which is usually not possible in traditional experiments.We used the ab initio pseudopotential method to study the effects of chemistry and structure on the voltage obtained from intercalating Li ions into transition metal oxides. The effect of transition metal and anion chemistry was systematically studied by changing M in LiMO2, (M=Ti, V, Mn, Co, Ni, Cu and Zn) and X in LiCoX2 (X=Se, S and O), keeping the structure fixed at α-NaFeO2 layered structure. In addition, the effect of structure was studied by performing computer experiments on LiCoO2 and LiMnO2 in α-NaFeO2, LiScO2 and Al2MgO4(spinel) structures.The computed voltages are in good agreement with experimental values. We found that, the electronic band structure and the extent of charge transfer between Li and O ions is correlated to the output voltage. We will explain how the output voltage is affected by the chemistry of the transition metal.
Lattice Dynamical Prediction of the Elastic Constants of Diamond
Authors: Reeber Robert R. 
Published: April 2011

AbstractThe thermophysical properties of diamond, a metastable material at room temperature, are difficult to measure at high temperatures. These properties are of interest for testing equation of state and interatomic potential models. Here we utilize a geometrical lattice transformation, one dimensional lattice dynamical theory, and the principle of corresponding states to calculate the elastic constants of diamond over an extended temperature range.
Crystal Growth at Low Temperatures - Solvothermal Synthesis and Crystal Structures of Two Mercury Tellurides
Authors: Li Jing , Chen Zhen , Kelley Jamal L. , Proserpio Davide M. 
Published: April 2011

AbstractTwo mercury tellurium compounds [Mn(en)3]2Hg2Te9 and {[Mn(en)3]2Cl2}(Hg2Te4) have been synthesized at 180°C by solvothermal reactions using ethylenediamine as solvent. Single crystal X-ray diffraction analyses show that both compounds crystallize in monoclinic system, space group P21/c (no. 14) with four formula units in the unit cell. The cell dimensions are: a = 12.019(1) Å, b = 28.731(4) Å, c = 18.267(4) Å, β = 98.04(1)°, V = 6246(2) Å3 for [Mn(en)3]2Hg2Te9 and a = 15.720(3) Å, b = 16.812(3) Å, c = 15.224(3) Å, β= 114.31(1)°, V = 3668(1) Å3 for {[Mn(en)3]2Cl2}(Hg2Te4).[Mn(en)3]2Hg2Te9 contains pseudo one-dimensional chains of weakly bound (Hg2Te9)4− Zintl anions. The structure of {[Mn(en)3]2Cl2}(Hg2Te4) contains one-dimensional chains of Zintl anion 1∞ [(Hg2Te4)2−] formed by linking five-membered rings Hg2Te3 through bridging Te atoms. In both structures ethylenediamine incorporates into the manganese complex cation as bidentate ligand.
Layered Cuprates
Authors: Salvador P. A. , Otzschi K. , Zhang H. , Mawdsley J. R. , Greenwood K. B. , Dabrowsi B. M. , Marks L. D. , Mason T. O. , Poeppelmeier K. R. 
Published: April 2011

AbstractLayered copper-oxide superconductors exhibit the highest critical transition temperatures of any materials. Yet all of the known double perovskites A′A″B′B″O6 containing copper have a random or rock salt distribution of the B cations with the exception of the unique layered arrangement found in La2CuSnO6. Only the layered arrangement contains the CuO22- planes which are necessary for high-temperature superconductivity. The occurrence of layered or two dimensional structures increases markedly when vacancies are introduced on the oxygen sublattice, as evidenced in Ln2AEmCu2TimO5+3m (Ln = lanthanide, Y: AE = Ba, Ca: 2 ≤ m ≤ 4). Similarities among oxygen-deficient structures, especially those with two-dimensional solid-state features, are discussed. Combined conductivity and thermopower analysis are presented to elucidate their unique internal chemistry, defect structure, and conduction parameters. In particular, data for La2-xSrxCuSnO6 are presented and related to the crystal chemistry of the copper-oxygen layer. These data are compared with La2Ba2Cu2Sn2O11 and La2Ba2Cu2Ti2O11 to illustrate the significance of oxygen vacancies on the properties of the copper oxygen planes. New layered cuprates are discussed including the mixed A-site stoichiometries Ln′Ln″AEmCu2TimO5+3m (Ln = lanthanide, Y: AE = Ba, Ca: 2 ≤ m ≤ 4) which contain the smaller lanthanide (Ln″) ordered between the closely spaced, facing sheets of Cu-O square pyramids.
Controlled Temperature Coefficient of Dielectric Constant Through Phase Transformation in (Ba, Sr)(Mg1/3Ta2/3)O3
Authors: Nagai T. , Sugiyama M. , Sando M. , Niihara K. 
Published: April 2011

AbstractA structural phase transformation from hexagonal to monoclinic has been found in an ordered perovskite compound (Ba, Sr)(Mg1/3Ta2/3)O3, (BSMT). The transformation temperature of BSMT increases and the dielectric constant also changes from 24 to 27 with an increase in Sr concentration. The temperature coefficient of the dielectric constant is also changed with the variation of Sr content. In order to apply BSMT for practical use of dielectric resonators these changes in the dielectric properties, which is dominated by the phase transformation, must be controlled. In order to clarify the relation between the dielectric constant change and the structural phase transformation, phonon mode of BSMT has been studied using Raman spectroscopy. Change in the Raman spectrum of BSMT is classified into four steps. The first and the fourth steps correspond to the phase transformation. The change in the phonon mode detected by Raman spectroscopy is discussed in connection with the structural change.
Fabrication and Dielectric Properties of Phase-Pure Ba2Ti9O20 Microwave Resonators
Authors: Lin Wen-Yi , Gerhardt Rosario A. , Speyer Robert F. , Hackenberger Wesley S. , Shrout Thomas R. 
Published: April 2011

AbstractThe thermal processing schedules necessary to form phase pure Ba2TigO20, with and without substitutional solid solution were investigated. Undoped compositions formed the compound most easily under rapid (500°C/min) heating rates, where diffusional agglomeration of the. TiO2 batch constituent was minimized. The compound formed most easily with minor (0.82%) substitutions of SnO2 and ZrO2 for TiO2. The solubility of Sn in Ba2Ti9O20 was higher than that of Zr. Extended heat treatment (16 vs. 6 h at 1390°C) resulted in volitalization of grain boundary liquid phase, leading to a more porous and slightly degraded resonators. The effects of dopant concentrations and soak periods at 1390°C on dielectric constants and temperature-dependent quality factors are reported.
Defect Structure of the Mixed-Conducting Sr-Fe-Co-O System
Authors: Ma B. , Balachandran U. , Chao C.-C. , Park J.-H. 
Published: April 2011

AbstractElectrical conductivity of the mixed-conducting Sr-Fe-Co-O system was investigated at elevated temperatures and various oxygen partial pressures (pO2). The system exhibits not only high combined electrical and oxygen ionic conductivities but also structural stability in both oxidizing and reducing environments. The conductivity of SrFeCo0.5Ox increases with increasing temperature and increasing pO2, within our experimental pO2 range (1 ≥ pO2 ≥ 1O-18 atm). p-type conduction behavior was observed. The activation energy of which increases with decreasing pO2. A model of the defect chemistry in the Sr-Fe-Co-O system is proposed. The pO2-dependent conducting behavior can be understood by considering the trivalent-to-divalent transition of the transition metal ions in the system.
Synthesis, Structure, Lattice Dynamics and Electrochemistry of Lithiated Manganese Spinel, LiMn2O4
Authors: Julien C. , Rougier A. , Nazri G. A. 
Published: April 2011

AbstractWe report synthesis, crystal structure, lattice dynamics, and electrochemical features of the lithiated manganese oxide spinel prepared through solid state reaction by careful selection of precursors and synthesis conditions. Elemental analysis shows that the material is a lithium-rich spinel phase. X-ray diffraction data and Rietveld refinement indicate formation of a single phase, impurity free, normal spinel of LiMn2O4. Lattice dynamics have been investigated by vibrational spectroscopy and group theoretical analysis has been carried out. Electrochemical performances of the lithiated spinel manganese oxide have been investigated, and the voltage profile of the cathode during lithium intercalation-deintercalation processes, close to equilibrium, has been obtained. The upper 4-volt plateau provides over 130 mA h/g with an excellent cyclability.