bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of Thin Nickel Silicide Layers on Clean B-Doped Si(111) Surfaces at Room Temperature
Authors: Luo L. , Smith G. A. , Gibson W. M. 
Published: March 2011

AbstractThe initial growth stages of Ni on clean B-doped Si(111) were studied at room temperature using high energy Ion channeling and Monte Carlo computer simulations of the Ni/Si interface. The results suggest that the first monolayer of Ni atoms diffuse to reaction sites in the fourth layer of the Si(111) substrate where nickel suicide growth begins. Further Ni deposition (up to ~ 3 ML) leads to the growth of NiSi2 which is thought to be a diffusion barrier that terminates further formation of NiSi2 at room temperature.
Preferential Growth of CoSi2 in Co/Si Solid State Interaction by Rapid Thermal Annealing
Authors: Liu Ping , Hong Feng , Li Bing-Zong , Sheng Xiao-Liang 
Published: March 2011

AbstractThe CoSi2 thin film growth by Co/Si solid state interaction was investigated. The electrical and crystal properties of the films formed on (111) and (100) Si substrates were characterized after a rapid thermal annealing. A strong preferential CoSi2 (111) orientation grain growth was observed on (111)Si substrate. The formed CoSi2 film was highly conductive with a resistivity of 15.5 µΩ · cm.
Silicide Formation and Thermal Stability of Ni/Si/GaAs Interface
Authors: Yamamoto Y. , Ishibashi K. , Suzuki S. , Shim T.E. 
Published: March 2011

AbstractThe suicide formation and thermal stability of the Ni/Si/GaAs structures have been investigated. Vacuum deposited Ni and Si onto a (100) GaAs were annealed at temperatures between 500 °C and 650 °C. In the case that the relative amount of Ni and Si was unity, a stoichiometric NiSi was formed and silicide/GaAs interface was quite stable. The Stoichiometric NiSi did not decompose into NiSi2 and Ni at a temperature of 650 °C. When Ni was in excess in amount for the formation of stoichiometric nickel suicides, free Ni atoms were generated, resulting in unstable interfaces.
Ordered Ternary Alloys by Atomic Layer Epitaxy
Authors: Mcdermott B.T. , Reid K.G. , Dip A. , El-Masry N.A. , Bed Air S.M. , Duncan W. , Yin X. , Pollak F.H. 
Published: March 2011

AbstractWe report on the successful growth of GalnP on GaAs substrate by Atomic Layer Epitaxy using organometallic and hydride sources. Growth was achieved by sequential exposure of the substrate to TMGa, PH3, TEIn and PH3. X-ray diffraction showed compositional lattice-matching optimally at 550°C with arbitrary choices of the mole fractions of the precursors in the gas phase. TEM also confirmed the highest ordering at this growth temperature on (100) substrates. Uniformity was excellent using Atomic Layer Epitaxy. Growth on (111)A GaAs substrates produced no evidence of the ordered CuPt phase present on (100) substrates.
Dislocation Density Reduction in GaAs Epilayers on Si Using Strained Layer Superlattices
Authors: Sharan S. , Narayan J. , Fan J. C. C. 
Published: March 2011

AbstractDefects such as dislocations and interfaces play a crucial role in the performance of heterostracture devices. The full potential of GaAs on Si heterostructures can only be realized by controlling the defect density. The reduction of threading dislocations by the use of strained layer superlattices has been studied in these heterostructures. Several superlattice structures have been used to reduce the density of threading dislocations in the GaAs epilayer. The use of strained layer superlattices in conjunction with rapid thermal annealing was most effective in reducing threading dislocation density. Transmission electron microscopy has been used to study the dislocation density reduction and the interaction of threading dislocations with the strained layers. A model has been developed based on energy considerations to determine the critical thickness required for the bending of threading dislocations.
A Tem Investigation of the Initial Stages of InSb Growth on GaAs (001) by Molecular Beam Epitaxy
Authors: Zhang X. , Staton-Bevan A.E. , Pashley D.W. 
Published: March 2011

AbstractThis investigation focuses attention on the very early stages of MBE growth of InSb on GaAs (001). Both conventional and high resolution TEM have been used for a study of InSb layers varying between 5 and 300 monolayers in average thickness. The observations provide conclusive evidence of 3D nucleation and island growth. Complete lattice relaxation is brought about by a network of 1/2 <110> Lomer dislocations at the InSb/GaAs interface and there is strong evidence for the presence of an additional sphalerite interfacial phase. Threading dislocations and planar defects in the InSb epilayer are mainly introduced during island coalescence.
Heteroepitaxial Growth of InP on GaAs with Interface Layer Grown by Flow-Rate Modulation Epitaxy
Authors: Chen W. K. , Chen J. F. , Chen J. C. , Kim H.M. , Anthony L. , Wie C. R. , Liu P. L. 
Published: March 2011

AbstractWe have grown and characterized heteroepitaxial films of InP on GaAs. We demonstrate that by using flow-rate modulation epitaxy to grow the interface layer in a two-step process, we can improve the quality of heteroepitaxy films. The full-widths-at-half-maximum of the x-ray rocking curve and the 10-K photoluminescence spectrum for a 6.2-μm-thick InP/GaAs are 144 arcsec and 1.28 meV, respectively.
Metalorganic Chemical Vapor Deposition of InP by Pulsing Precursors
Authors: Chen W. K. , Chen J. C. , Anthony L. , Liu P. L. 
Published: March 2011

AbstractWe have grown InP by supplying precursors alternately into the reactor of a metalorganic chemical vapor deposition system. Epitaxial growth has been obtained with a substrate temperature as low as 330 °C. The growth process is mass-transport-limited in the temperature range of 420 to 580 °C. It is kinetic-controlled below 400 °C. At 340 °C, we have achieved monolayer growth in each cycle, i.e., atomic layer epitaxy.
Determination of 3-Dimensional Defect Structures in Gallium Arsenide Epilayers on Silicon Using White Beam Synchrotron Radiation Topography in both Transmission and Grazing Bragg-Laue Geometry.
Authors: Dudley M. , Yao G.-D. , Wu J. , Liu H.-Y. , Kao Y.C. 
Published: March 2011

AbstractWhite beam synchrotron topography in both transmission and grazing Bragg-Laue geometries has been used to reveal the 3-dimensional defect structure in MBE grown GaAs epilayers on Si. Defects observed and characterized include substrate threading dislocations and interfacial dislocations. Dislocation line direction and Burgers vector analysis was performed on transmission topographs. The relationship between substrate threading dislocations and interfacial dislocations was established. In the grazing Bragg-Laue case, manipulation of geometry enabled depth profiling of defect structures in the epilayer. The position of the interfacial dislocations was verified by correlating penetration depth analysis with the visibility of the dislocations under different diffraction conditions.This technique affords a rapid and non-destructive way of quantitatively characterizing processing induced damage in such systems.
Selective Area Growth of GaAs on Si by Electron-Cyclotron-Resonance Plasma-Excited Molecular-Beam-Epitaxy (ECR-MBE)
Authors: Shibata Tomohiro , Kondo Naoto , Nanishi Yasushi , Fujimoto Masatomo 
Published: March 2011

AbstractSuccessful selective area growth of GaAs on Si following low-temperature plasma cleaning of the Si surface is carried out by ECR plasma-excited MBE. Both cleaning and selective area growth are carried out at 630° C. GaAs selectively grows only in Si windows patterned in the SiN mask. Neither deposition on the SiN mask nor anomalous growth at the mask edge is observed. GaAs thickness is independent of the SiN mask width, which implies that the plasma-enhanced desorption of migrating atoms from the SiN mask is essential in this selective area growth. Furthermore, results for the helium-diluted arsine imply that the plasma-enhanced desorption is mainly caused by physical bombardment.
Raman Study of MOMBE and Plasma-MOVPE Grown III-V Layers on Si(100).
Authors: Geurts J. , Finders J. , Münder H. , Kamp M. , Oehlers M. , Loth H. , Musolf J. , Leiber J. , Brauers A. , Weyers M. , Balk P. 
Published: March 2011

AbstractThe crystalline quality of the transition region between buffer layer and epilayer in MOMBE (metalorganic molecular beam epitaxy) and plasma-MOVPE (metalorganic vapour phase epitaxy) grown GaAs layers on Si(100) is analysed by Raman scattering with variation of the penetration depth and besides bevel polishing or step etching. The region with considerable lattice imperfections is essentially confined to the original buffer layer.
Magnetic Properties of Al/Tb-Fe-Co Multilayer Thin Films
Authors: Barnard J.A. , Yan B.D. , Kim M.H. , Warren G.W. 
Published: March 2011

AbstractA series of periodic multilayer Al/Tb-Fe-Co thin films have been prepared by dc-magnetron sputtering. The films are of the form (xA/yB)n, where x and y are the thicknesses of the A and B layers respectively, and n is the number of bilayer units. Individual layers are from 2-40nm thick. The magnetic properties of the films have been measured as a function of Al and Tb-Fe-Co layer thicknesses by vibrating sample magnetometry (VSM). An homogeneous film of the Tb-Fe-Co alloy was grown under identical conditions and found to have in-plane easy magnetization. Pronounced interfacial and/or reduced dimension effects have been found in the multilayer systems. These include evidence for a “dead layer” in the interface regions (~2nm thick) and reversal of the direction of easy magnetization from in-plane (in the homogeneous thin film samples) to strongly perpendicular in the multilayer configuration.
Time Resolved Measurements of Radiative Recombination in GaAs/AIGaAs Heterostructures
Authors: Bergman J.P. , Zhao Q.X. , Holtz P.-O. , Monemar B. , Sundaram M. , Merz J.L. , Gossard A.C. 
Published: March 2011

AbstractThe radiative recombination of two-dimensional (2D) carriers in an n-channel GaAs/AIGaAs heterojunction has been studied with time resolved photoluminescence (PL). Two bands related to the recombination of 2D carriers, the so called H-band 1 (HB1) and H-band 2 (HB2), are observed in PL. The spectral shape and position is strongly dependent on the sample and the experimental conditions. The H-bands are e.g. found to shift within a large energy range with the excitation intensity. We report here on the dependence of the decay times of the H-bands on their spectral position. The results are consistent with a recombination process involving 2D electrons, confined in the interface notch, and three-dimensional (3D) holes either from the valence band (HB1) or from neutral acceptors (HB2) in the active GaAs layer. The decay times of HB1 are found to vary in the range of 2-100 ns, while the corresponding decay times of HB2 are in the range of 100 ns - 10 µs.
Dislocation Behaviour in GexSi1-x Epilayers on (001)Si
Authors: Kvam Eric P. , Maher D.M. , Humphreys C.J. 
Published: March 2011

AbstractWe have observed that the nature of misfit dislocations introduced near the critical thickness in GexSi1-x alloys on (001)Si changes markedly in the region 0.4 ≤ x ≤ 0.5. At or below the lower end of this compositional range, the observed microstructure is comprised almost entirely of 60° type dislocations, while at the high end, the dislocation structure is almost entirely Lomer edge type. Concurrent with this change, the dislocation density at the top of the epilayer varies by a factor of about 60X. Similarly, several other observables (e.g. dislocation length and spacing) also change appreciably.Part of the reason for the morphological variation seems to be a change in the source for dislocation introduction, in conjunction with a change in glide behaviour of dislocations as a function of film thickness. Evidence will be presented that indicates strain, as well as thickness, has a critical value for some dislocation introduction mechanisms, and that these together determine the resulting microstructure.Furthermore, it appears unlikely that the edge-type Lomer dislocations which appear at about x = 0.5 are either introduced directly, by climb, or grown in, as in the three-dimensional island growth and coalescence which occurs when x approaches unity. Instead, a two-step mechanism involving glissile dislocations is proposed and discussed.
Spatially Indirect Optical Transitions in Semiconductor Multiple Quantum Wires
Authors: Weiner J. S. , Danan G. , Pinczuk A. , Valladares J. , Pfeiffer L. N. , West K. 
Published: March 2011

AbstractIn optical experiments with laterally patterned modulation-doped GaAs/AlGaAs quantum wells we observe spatially separate confinement of electrons and holes to one-dimensional quantum wires. We determine the one-dimensional subband spacing and Fermi energy from inelastic light scattering and photoluminescence spectra. From these measurements we directly determine the one-dimensional electron density.
Lattice Mismatch Effects in GaAsP/GaAs and GaAs/GaAsP/GaAs Heterostructures
Authors: Choi Y.W. , Wie C.R. , Vernon S.M. 
Published: March 2011

AbstractStructural and electrical characteristics of the GaAs1-xPx / GaAs and GaAs/GaAs1-xPx/GaAs (x=0.02, 0.05, 0.08, 0.16 and 0.32) hetero-epitaxial systems have been investigated using X-ray rocking curve technique, Optical Beam Induced Current imaging, Nomarski Micrograph, and I-V-T and C-V measurements. The rocking curve Full Width Half Maximum of the GaAs1-xPx epilayer increased sharply at x=0.16 due to a decreased layer thickness and increased in-plane mismatch. The cross-hatched line density in the OBIC image and Nomarski Micrograph increases as the lattice mismatch increases. The epilayer surface morphology is dependent on the layer thickness. The forward I-V characteristics of Au-GaAsP/GaAs and Au-GaAs/GaAsP/GaAs Schottky diodes showed an increased tunneling current for an the increased lattice mismatch. For GaAsP/GaAs structure with a higher phosphorus composition, Fermi-level pinning caused by misfit dislocation was observed. Au-GaAs/GaAsP/GaAs Schottky diodes show an excess current at the low temperature, high field range which, we believe, is due to defect related tunneling.
A Stable n-Channel Indium Phosphide Field-Effect Transistor with an Amorphous Hydrogenated Silicon Gate
Authors: Roditi E. , Iliadis A.A. , Christou A. 
Published: March 2011

AbstractInP field-effect transistors fabricated with an amorphous hydrogenated Si (a-Si:H) gate resulted in metal-insulator-like FET characteristics with no observable current drift and a transconductance of 30–38 mS/mm. The high stability of this gate system is attributed to the low temperature of deposition and the hydrogen passivation of the InP surface.
Effects of Oxygen on Diamond Growth
Authors: Harris Stephen J. , Weiner Anita M. 
Published: March 2011

ABSTRACTIn situ mass spectral measurements of the gas composition at the substrate surface were made during filament-assisted diamond growth. The input gases were various mixtures of CH4, O2, and H2chosen in order to discern the effects of oxygen addition on diamond formation and growth. The gas phase chemistry was modeled as a 1-dimensional flow reactor, and the measured and calculated species mole fractions were in good agreement. The model was then used to estimate mole fractions of several atomic and radical species which could not be measured. We find that addition of O2has only a small effect on the radical mole fractions. However, O2can reduce the effective initial hydrocarbon mole fraction, which is important because higher quality diamond is grown at lower initial hydrocarbon mole fraction. Most importantly, perhaps, O2addition leads to the formation of sufficient gas phase OH to remove non-diamond (pyrolytic) carbon from the film. Thus, O2addition allows diamond films to be grown under composition and temperature conditions which otherwise would produce largely non-diamond carbon.
Oxygen Effect in Diamond Deposition at Low Temperatures
Authors: Liou Y. , Inspektor A. , Weimer R. , Knight D. , Messier R. 
Published: March 2011

ABSTRACTDiamond thin films were deposited on different substrates at low temperatures (lowest temperature∼ 300°C, estimated) in a microwave plasma enhanced chemical vapor deposition (MPCVD) system. The deposited films were amorphous carbon or diamond films depending on the different gas mixtures used. The growth rate of diamond thin films was decreased by adding oxygen to the gas mixture. The addition of oxygen to the gas mixtures was found to be important for diamond growth at low temperatures. Different concentrations of oxygen have been added into the gas mixture. Without oxygen, the deposited films were white soots and easily scratched off. Increasing the oxygen input improved the quality of the Raman peaks and increased the film transpancy. The diamond films were also characterized by scanning electron microscopy (SEM).
Bias Controlled Hot Filament Chemical Vapor Deposition of Diamond Thin Film on Various Substrates
Authors: Lee Y. H. , Ma G.-H. , Bachmann K. J. , Glass J. T. 
Published: March 2011

ABSTRACTThe growth of diamond films on Si(001), polycrystalline Ni, Mo, Ta, and W substrates by biased controlled chemical vapor deposition is discussed. Biasing effects were examined using the Si(001) substrates. The film quality as judged by Raman spectroscopy and scanning electron microscopy depended strongly on the biasing conditions. Under low current reverse bias conditions, highly faceted cubooctahedral polycrystalline diamond growth exhibiting a single sharp Raman line at 1332 cm-1 was obtained. Transmission electron microscopy indicated that these films contained relatively low defect densities and no significant interfacial layers. Biasing into high current conditions which created a plasma resulted in multiply twinned, microcrystalline growth incorporating sp2 bonded carbon into the diamond film. Such films were found to contain very high defect densities and a relatively thick interfacial layer. An investigation of the effects of substrate material was also conducted. Films grown on Si, Ni and W exhibited the best quality. The relationship between this quality and substrate properties such as surface energy and lattice parameter is discussed.
Importance of Filament Reactivity for CVD Diamond Growth
Authors: Sommer M. , Smith F. W. 
Published: March 2011

ABSTRACTThe behavior of tungsten filaments heated up to 2500°C in mixtures of CH4 or C2 H2 and H2 at P = 9 and 25 Torr is analyzed. It has been found that the filament resistance R, spectral emissivity ?, power consumption, and CH4 and C2H2 partial pressures depend critically onl the filament temperature as well as the reactant CH4/ H2 or C2H2/ H2 fraction. We interpret these results on the basis of a thermodynamic model which predicts that transitions between deposition and etching of solid carbon occur on the filament surface at high temperatures. The implications of these results for diamond CVD are discussed. Evidence for gas phase reactions is also presen ted.
Free Standing CVD Diamond Shapes and Coatings
Authors: Patterson Donald E. , Hauge Robert H. , Margrave John L. 
Published: March 2011

ABSTRACTThe success of the emerging CVD diamond film industry will depend to a great extent on how well these films can be put to practical applications. Our research is presently focusing on the development of methods for the growth of large thin wall diamond shapes which can be subsequently strongly bonded to other support materials. The shapes such as cylinders, hemispheres, etc. will be designed to take advantage of diamond's superior hardness and thermal conductivity. As these diamond shapes also promise low friction and long wearing surfaces, they have potential uses as bearing surfaces as well as very scratch resistant covers for mirrors and lenses. Our primary research objectives will be concerned with: 1. The development of various apparatus to grow selected shapes of CVD diamond. 2. The development of techniques to transfer and bond the films onto materials other than the original substrates. 3. The physical and chemical characterization of the diamond films, composites, and final products.
KrF Laser-Induced Chemical Vapor Deposition of Diamond
Authors: Tyndall George W. , Hacker Nigel P. 
Published: March 2011

ABSTRACTA KrF* (248 nm) laser-based process for the deposition of carbon films containing a large fraction of diamond is reported. The experiment consists of focusing the pulsed laser beam at normal incidence onto the surface of a low temperature (20° - 150° C) silicon substrate in the presence of acetic or malonic acid vapor. The process does not require the presence of hydrogen, although an inert buffer gas, e. g. argon, is usually employed. Deposition rates of approximately 1 μm - hour−1 are obtained, and the presence of diamond in the deposited film is inferred from Raman Spectroscopy and Auger Electron Spectroscopy.
Nuclear Magnetic Resonance Spectroscopy in the Study of Diamond Thin Films
Authors: McNamara Karen Mary , Gleason K. K. , Geis M. W. 
Published: March 2011

ABSTRACTNuclear magnetic resonance spectroscopy has been used to study diamond thin films grown in a low-pressure hot-filament reactor from 13C-labeled acetone. Film quality is assessed, and the origin of deposited carbon determined. Carbon atoms from both bonding environments in the acetone molecule deposit to form only sp3-bonded material. The relative rate of incorporation of these carbon atoms is determined. Experimental results and equilibrium calculations demonstrate that CO acts as a precursor for diamond growth in the absence of heterogeneous kinetics.
Photoluminescence Spectroscopy of Diamond Films
Authors: Freitas J. A. , Butler J. E. , Bishop S. G. , Carrington W. A. , Strom U. 
Published: March 2011

ABSTRACTPhotoluminescence spectroscopy has been used to characterize polycrystalline diamond films prepared by filament assisted chemical deposition and by combustion (in an oxygenacetylene flame) techniques. The luminescence spectra of the chemical vapor deposited films are dominated by a defect band possibly associated with a neutral vacancy with a strong zero phonon line at 1.68 eV and weak phonon replicas at lower energies. The combustion films exhibit two additional luminescence bands with zero phonon lines at 1.95 and 2.16 eV. The 1.95 eV band has been tentatively assigned to a nitrogen-vacancy pair. We have also observed a strong dependence of the PL spectra radially across a given combustion film and associated this with details of the flame chemistry.
Laser Emission from Natural Diamonds
Authors: Santos Lucilia , Pereira Estela 
Published: March 2011

ABSTRACTThe red luminescence band which is a strong broad band that occurs in natural diamonds, showing a zero phonon line at 2.145 eV and a coupling to a nearly localized phonon of 30 meV with a Huang-Rhys factor of 10, and a constant intensity up to room temperature, is shown to present tunable stimulated emission at room temperature. The stability of the band towards strong pumping conditions is discussed. Another strong luminescent band (S3) is shown to present excited state absorption.
Electrical Properties of Thin Film and Bulk Diamond Treated in Hydrogen Plasma
Authors: Albin Sacharia , Watkins Linwood 
Published: March 2011

ABSTRACTCurrent-voltage characteristics of type Ia synthetic diamond, type IIb natural diamond and free-standing diamond films were measured before and after hydrogenation. The diamond films were polycrystalline, deposited on sacrificial silicon substrates using a microwave chemical vapor deposition process. On hydrogenation, all the samples showed several orders of magnitude increase in conductivity. Hydrogenation was carried out under controlled conditions to study the changes in the I-V characteristics of the samples. The concentration of electrically active hydrogen was determined from the I-V data. Hydrogen passivation of deep traps in diamond is clearly demonstrated.