bluuebunny/crossref_metadata_2025_split huggingface dataset:
-Search For a Correlation Between Stoichiometry,TSC Spectra and -NUclear Spectroscopic Capabilities of HCI2.
Authors: Tadjine A. , Gosselin D. , Koebel J.M. , Siffert P. 
Published: March 2011

ABSTRACTMercuric iodide is, potentially, an interesting material for room temperature high efficiency gamma or X-ray spectroscopy. However, still several parameters limit the performance of these devices and even the crystal growth is not fully under control today, poor reproductibility being reached.An optimization of growth conditions seems difficult since no parameter of the material could be correlated with the spectrometer's performance. Therefore, the effective progress in recent years was rather limited.The goal of this paper is to investigate systematically if a correlation can be found between bulk stoichiometry for crystal grown under certain conditions, thermally stimulated current (TSC) measurements and nuclear performance. In this study, two families of crystals could be identified. Best results are obtained for nearly stoichiometric materials, exhibiting a specific TSC spectrum. In particular, the peak appearing at 173 K constitutes a good indication of the detection capabilities of the material, both for spectroscopic resolution and polarization.The growth conditions have been adjusted to produce in a fully reproducible way high performance devices.
The Characterization of Germanium and Silicon for Nuclear Radiation Detectors.
Authors: Darken L. S. 
Published: March 2011

ABSTRACTSemiconductor nuclear radiation detectors require deep depletion depths (0.03–3.0 cm) and effective charge collection distances which are several times longer than these depletion depths. These requirements place stringent limitations on the net electrically active impurity concentration, and on the concentration of deep centers which can trap carriers generated by the incident nuclear radiation. This need for extremely pure material distinguishes the interests and efforts of the semiconductor detector community from the rest of the semiconductor community. This paper reviews the characterization of shallow-level, deep-level, neutral, and extended defects in germanium and silicon for nuclear radiation detectors. Photothermal ionization spectroscopy has been used extensively to identify the residual hydrogenic impurities in high-purity (∣NA–ND∣ ≈ 1010–1011 cm−3 ) germanium and silicon. Deep level transient spectroscopy has been effectively used to detect and identify deeper levels in high-purity germanium. Residual neutral defects are not necessarily passive: they may complex to form deep or shallow levels, they may precipitate, or they may act as nucleation sites for precipitation. The properties of extended defects (dislocations, lineage, inclusions, precipitates) and their effects on device performance are fundamentally less well understood, as the origin of the electrical activity of these defects is uncertain. It has been found in numerous instances that chemical interactions among defects are important even in these high-purity semiconductors.
Structural Characterizations of Symmetrically Strained Sim Gen Superlattices
Authors: Bowman R. C. , Adams P. M. , Ahn C. C. , Chang S. J. , Arbet V. , Wang K. L. 
Published: March 2011

AbstractMolecular beam epitaxy was used to grow Sim Gen superlattices on relaxed Si1-xGex buffer layers which symmetrize the strains between the heteroepitaxial layers. Samples with different superlattïce periodicities and individual layer thickness ratios were prepared. The compositions and defect structures of the GexSi1-x buffers have significant influence on the homogeneity and quality of the overlying superlattices. In particular, greater disorder was found in superlattice structures grown on Si0.5 Ge0.5 buffers than for those grown on buffer layers with significantly higher or lower Ge contents.
Modified Dislocation Structures in GexSi1-x Double Epilayers on (001)Si
Authors: Kvam Eric P. 
Published: March 2011

AbstractDouble epilayers of different compositions of GexSi1-x on (001)Si are observed to have dislocation contents which differ markedly from similar single epilayers. An initial epilayer, grown below its critical thickness, underwent substantial misfit dislocation introduction, while a second epilayer, grown at a composition where edge-type misfit dislocations are normally observed to dominate the morphology, contained mostly 60° type dislocations. It is suggested that dislocation entry into the upper, high mismatch epilayer allows many dislocations to enter the buried, low mismatch epilayer, and that this in turn affects the dislocation morphology in the upper layer through strain relief.
Thermal Strain Study of Almost Lattice-Matched Epitaxial InuGa1-uAs1-vP1-v Films on InP(100) Substrates
Authors: Bai G. , Nicolet M-A. , Kim S.-J. , Sobers R.G. , Lee J.W. , Brelvi M. , Thomas P.M. , Wilt D.P. 
Published: March 2011

AbstractSingle layers of ~ 0.5µm thick InuGa1-uAs1-vPv (0.52 < u < 0.63 and 0.03 < v < 0.16) were grown epitaxially on InP(100) substrates by liquid phase epitaxy at ~ 630°C. The compositions of the films were chosen to yield a constant banndgap of ~ 0.8 eV (λ = 1.55 µm) at room temperature. The lattice mismatch at room temperature between the epitaxial film and the substrate varies from - 4 × 10-3 to + 4 × 10-3. The strain in the films was characterized in air by x-ray double crystal diffractometry with a controllable heating stage from 23°C to ~ 700°C. All the samples have an almost coherent interfaces from 23°C to about ~ 330°C with the lattice mismatch accomodated mainly by the tetragonal distortion of the epitaxial films. In this temperature range, the x-ray strain in the growth direction increases linearly with temperature at a rate of (2.0 ± 0.4) × 10-6/°C and the strain state of the films is reversible. Once the samples are heated above ~ 300°C, a significant irreversible deterioration of the epitaxial films sets in.
Rayleigh Acoustic waves in fcc/fcc Metallic Superlattices
Authors: Dutcher John R. , Lee Sukmock , Kim Jeha , Stegeman George I. , Falco Charles M. 
Published: March 2011

AbstractThe Rayleigh acoustic waves of sputter-deposited Cu/Co, Ag/Pd and Cu/Pd sup-erlattice films were studied using Brillouin scattering. All three of these systems are fcc/fcc superlattices. The dependence of the Rayleigh wave velocities for these films on the superlattice modulation wavelength is discussed.
Epitaxial growth of Cu-Ni Single Crystal Alloys and Multilayers by Molecular Beam Epitaxy
Authors: Burns R.P. , Lee Y.H. , Parikh N.R. , Posthill J.B. , Mantini M.J. , Markunas R.J. 
Published: March 2011

AbstractEpitaxial growth of thin films, alloys, and multilayers from the Cu-Ni system are being explored as a means of fabricating a substrate to lattice match diamond. These single crystal films are superior to commercially available substrate material. Due to the high reactivity of the metal surfaces in atmosphere, all processing must be done under UHV conditions. In vacuo preparation, growth, and analysis of the metals is described.
Model for Epitaxial growth of Cobalt on CU(100)
Authors: Vvedensky Dimitri D. , Clarke Shaun 
Published: March 2011

AbstractThe epitaxial growth kinetics of Co on Cu(100) are investigated with a kinetic solid-on-solid model. Two effects are found to dominate the growth of this system reflecting the difference in surface free energies betweenthe two materials: the difference of diffusion parameters, and the inability of Co to wet Cu(100) at lower temperatures.
Kinetic Barriers to Strain Relaxation in GexSi1-x/Si Epitaxy
Authors: Hull R. , Bean J.C. 
Published: March 2011

AbstractWe discuss the kinetic barriers to misfit dislocation nucleation, propagation and interaction in lattice-mismatched GexSi1-x/Si epitaxy. Experimental real-time observations of the strain relaxation process via in-situ annealing experiments in a transmission electron microscope enable each of these processes to be separately studied. Quantitative parameters defining misfit dislocation processes may be derived; these are found to be highly dependent upon the structure geometry. The approximations involved in extending these measurements to a description of the relaxation process during growth are described in detail.
Growth and Characterization of Epitaxial CoSi2 on Si(001)
Authors: Jimenez J.R. , Hsiung L.M. , Thompson R.D. , Hashimoto Shin , Ramanathan K.V. , Arndt R. , Rajan K. , Iyer S.S. , Schowalter L.J. 
Published: March 2011

AbstractThe structural and electrical properties of epitaxial CoSi2, grown on Si(001) by molecular beam epitaxy, have been investigated. Most growth conditions successful on Si(111) have been found to result in misoriented grains when applied to Si(001). However, single-orientation (001) CoSi2 films, with low resistivities (16 µΩ-cm) and low ion channeling minimum yields (χmin=5%), have been obtained by direct codeposition of Co and Si at ~500°C at Co-rich stoichiometries. Single orientation (001) CoSi2 films have also been obtained by using a template method on epitaxially grown Si buffer layers, but the resistivities of these films have not been as good. A Schottky barrier height of 0.71 eV has been measured for single-orientation CoSi2(001)/Si(001). This is significantly higher than the barrier height of 0.64 eV for CoSi2(111)/Si(111).
Epitaxial Growth of TbSi2 on Si(111)
Authors: Kaatz F.H. , Graham W.R. , Van der Spiegel J. 
Published: March 2011

AbstractWe describe the epitaxial growth of TbSi2. In this study, terbium metal is evaporated onto (111) silicon and annealed to form terbium suicide, where the pressure during all procedures is maintained below 5×10-10 Torn The interdiffusion of terbium with silicon occurs at room temperature as determined by in-situ Auger electron spectroscopy. Low energy electron diffraction shows a sharp pattern of the hexagonal suicide after an 850°C anneal. Rutherford backscattering analysis indicates single-crystal growth with a channeling minimum yield of 7–8% for 120Å thick suicide films annealed to 800–900°C. These metal reacted films have pinholes with an average size of less than 0.5 µm and a fault structure along (220) silicon. Electrical measurements show metallic conduction with a room temperature resistivity of 110 µΩ-cm and evidence of magnetic ordering at 38K.
Solid Phase Epitaxy of GexSi1-x Alloys on [100] Si
Authors: Hong Q. Z. , Revesz P. , Yu A. J. , Mayer J. W. , Poate J. M. , Bean J. C. , Eaglesham D. J. 
Published: March 2011

AbstractSolid phase epitaxy was studied in the GexSi1-x/[100] Si system in the composition range of 4% to 10% Ge. For strained samples regrowth rates decreased with increasing Ge concentrations, with an activation energy of 2.8 and 3.0 eV for the Ge4Si96 and Ge8Si92 alloys respectively. In contrast, the rates of the strain-relaxed samples increased compared with that of pure Si. The minimum yield of fully regrown samples with Ge concentrations lower than 8% recovered to that of the as-deposited samples. However, the minimum yield of a 3500 Å-thick Ge10Si90 alloy increased to 12 % after recrystallization.
Solid Phase Epitaxy of Si1-xGex on Si Strained Layers
Authors: Robinson B.J. , Chilton B.T. , Ferret P. , Thompson D.A. 
Published: March 2011

AbstractSingle strained layer structures of up to 30 nm of Si1-xGex. on (100) Si and capped with 30-36 nm of Si have been amorphized by implantation with 120 keV As . The amorphized region, extending to a depth of 130 nm, has been regrown by solid phase epitaxy (SPE) at 600°C. Characterization of the regrown structure by Rutherford backscattering/channeling techniques and transmission electron microscopy indicates that for x < 0.18 the SPE process results in the recovery of strain, while for x > 0.18 there is increasing strain relaxation and a deterioration of crystal quality.
Effects of Substrate Misorientation and the Growth Mechanism of Si Doped GaAs Grown on (111)A Substrate by MBE
Authors: Okano Y. , Seto H. , Shigeta M. , Nishine S. , Fujimoto I. , Suzuki T. 
Published: March 2011

AbstractThe MBE growth of Si doped GaAs on slightly misoriented (111)A substrates was examined. The conduction types and the carrier concentrations were greatly affected by the degree of substrate misorientation. In the growth on an exactly (111)A oriented substrate, substantially all Si atoms acted as acceptors. With increase of the degree of misorientation and/or with increase of the flux ratio (JAs4/JGa), the number of donor-site Si atoms increased, that is, the hole concentration first decreased by autocompensation of Si and then the conductivity reversed from p-type to n-type. The photoluminescence of highly compensated (111)A films showed characteristics of donor-acceptor pair recombination. A doping mechanism including preferential decomposition of As4 molecules at the steps was proposed.
Step Profile Fluctuations in Quantum-Well Wire Growth on Vicinal Surfaces
Authors: Hugill K.J. , Shitara T. , Clarke S. , Vvedensky D.D. , Joyce B.A. 
Published: March 2011

AbstractMolecular-beam epitaxy of quantum-well wires on vicinal surfaces is studied by application of Monte Carlo simulations of a solid-on-solid model. Characterization of simulated quantum-well wires indicates an optimum regime within which the quality of the quantum-well wire is maximized. The model is extended to include observed anisotropies in GaAs growth on vicinal surfaces, and the conclusion is reached that better quality quantum-well wires may be grown on substrates misoriented from the (001) towards [110], rather than [110], due to relative step edge stability on the two misoriented surfaces.
Metalorganic Magnetron Sputter Deposition of In1-xGax on (100)GaAs
Authors: Rousina R. , Webb J.B. , Noad J.P. 
Published: March 2011

AbstractThis work reports for the first time, the epitaxial deposition of ln1-xGaxSb on (100)GaAs by Metalorganic Magnetron Sputtering. High quality films could be deposited on GaAs over the entire compositional range despite the large lattice mismatch between the film and substrate (14.6% for InSb and 7.8% for GaSb). The composition of the layers was found to be directly related to the trimethylgallium and trimethylindium fluxes at constant growth temperature. Growth rates of 1 µm/hr for the GaSb and 3 µm/hr for the InSb were observed.
Energetics and Relaxations of Adatom, Dopant and Vacancy Related Complexes on Normal and Strained GaAs(001) Surface
Authors: Ogale S.B. , Madhukar A. , Viswanathan R. 
Published: March 2011

AbstractSurface complexes involving Ga and Si adatoms, Si dopant and As vacancies at the GaAs (001) surface are examined for their energetics and associated structural relaxations by employing semi-empirical two- and three-body potential energy functions. The energy minimization is achieved via the simulated annealing Monte carlo procedure. An 8 X 8 X 8 GaAs matrix is used with periodic boundary conditions in the lateral plane. The adatom, dopant or vacancy is added to the system after allowing the top two surface layers to reconstruct into a c (2 × 2) pattern. The suitably chosen neighborhood of the modified site is then allowed to relax to a minimum energy configuration. The complexes are studied for both the unstrained and strained surfaces.
Liquid Phase Electroepitaxial (LPEE) Growth of GaSb and GaInAsSb
Authors: Iyer Shanthi N. , Abul-Fadl Ali , Macrander Albert T. , H.Lewis Jonathan , Collis Ward J. , Sulhoff James W. 
Published: March 2011

AbstractLiquid phase electroepitaxial technique has been used for the growth of GaSb and GalnAsSb in the composition range corresponding to peak band gap wavelengths of 1.7-2.28μm. The growth rate of these layers were examined as a function of current density. The growth rates of these layers are typically 0.8μm/min. at a current density of 10A/cm2. The quality of the layers was evaluated by x-ray diffraction and room temperature photoluminescence.
Rapid Growth of Thick, IC Quality GaAs From a Flowing Solution
Authors: Crismant E. E. , Daly J. T. , Roberts C. B. , Schaafsma D.T. , Gerritsen H. J. , Karlsson S. K. F. 
Published: March 2011

AbstractSingle crystal layers of gallium arsenide have been grown on <111> and <100> oriented GaAs substrates using a flowing solution of gallium saturated with GaAs. With this novel technique, growth rates as high as 9.Oµm/min have been achieved for 5 minutes, while rates of approximately Aµmlmin are typically achieved for 20 minutes of growth. These figures are in good agreement with a previously developed theoretical model and are about two orders of magnitude greater than those for conventional, static solution, liquid phase epitaxy (LPE) for layer thicknesses greater than lµm. Undoped, p-doped and n-doped layers of high crystallographic and electronic quality have been grown. A description of the technique and some of the electro-optical properties are presented in this paper.
High Quality GaAs on Soi by MOCVD
Authors: Karam N.H. , Haven V. , Vernon S. , Ramdani J. , El-Masry N. , Haegel N. 
Published: March 2011

AbstractEpitaxial GaAs films have been successfully deposited on three-inch Si wafers with a buried oxide by MOCVD. The SOI wafers were prepared using Separation by IMplantation of OXygen (SIMOX) process. High quality GaAs on SIMOX films, with dislocation density in the range of 2–6 × 106 cm-2, have been achieved using Thermal Cycle Growth (TCG) deposition technique. These films showed a 50-fold increase in the low temperature photoluminescence intensity over conventional deposition. We have also fabricated MESFET’s in GaAs on SIMOX with performance comparable to those fabricated in GaAs. The maximum measured transconductance was in the range of 175-180 ms/mm at a 1.5 µm gate length and a 5 µm source to drain separation. This is the first demonstration of large area, high quality and low defect density GaAs on SIMOX.
Epitaxial Growth of (100) GaAs on SOS using a Specifically Designed MOCVD System
Authors: Nishimura T. , Kadoiwa K. , Mitsui K. , Murotani T. 
Published: March 2011

AbstractHigh quality (100) single domain GaAs layers are epitaxially grown on slightly misoriented (100) Si-on-(1102) sapphire(SOS) substrates by MOCVD. Epitaxial growth on a spherical SOS substrate reveals that R face (1102) should not be tilted toward C axis [0001], but toward [011] or [011] of Si. A new MOCVD system which has two reactors, one for Si cleaning, the other for GaAs deposition, is effective to obtain mirrorlike smooth surface. The X-ray FWHM of 10µm GaAs was reduced to 65 arcsec by the thermal cycle annealing.A crack free 15 µm thick GaAs layer with a dislocation density of 3×106cm-2 is obtained by combining the thermal cycle annealing and the strained-layer superlattices.
The Role of an Interface Misfit Dislocation in Blocking the Glide of a Threading Dislocation in a Strained Epitaxial Layer
Authors: Freund L. B. , Ramirez J. C. , Bower A. F. 
Published: March 2011

AbstractThe glide of a threading dislocation in a strained layer may be impeded as it encounters interface misfit dislocations on intersecting glide planes. An estimate of the change in driving force on the threading dislocation during this interaction is discussed within the framework of elastic dislocation theory.
Influence of Off-Oriented Substrates on Heteroepitaxial Growth of (Ca, Sr)F2 Layers on Si (100)
Authors: Minemura Tetsuroh , Asano Junko , Tsutsui Kazuo , Furukawa Seijiro 
Published: March 2011

AbstractHeteroepitaxial growth of CaxSr1-xF2 layers on Si (100) substrates by molecular beam epitaxy has been investigated for GaAs / fluoride / Si structures. The Si (100) substrates off-oriented toward [011] show no considerable influence on crystallinity of CaF2 and SrF2 epitaxial layers. The off - oriented substrates, however, influence a remarkable effect on CaxSr1-xF2 layers, resulting in poor crystallinity rather than good one. This influence of off-oriented Si (100) substrates on the heteroepitaxy of CaxSr1-xF2 layers was the opposite of that found in GaAs/Si (100) structures.
Strain in Epitaxial GaAs on CaF2/Si(111)
Authors: Schowalter L.J. , Ayers J.E. , Ghandhi S.K. , Hashimoto Shin , Gibson W.M. , LeGoues F.K. , Claxton P.A. 
Published: March 2011

AbstractEpitaxial layers of (111) GaAs of approximately 1 µm thickness were grown on epitaxial CaF2 buffer layers which were either 140 or 380 nm thick on Si(111) substrates. The best nucleation temperature for the GaAs on CaF2/Si(111) we have observed was 620 °C. This resulted in high quality GaAs films which exhibited channeling minimum yields of 4%. The density of threading dislocations in the GaAs layers was observed by TEM to be ~108 cm-2. Double-crystal x-ray diffraction measurements showed that the strain (ε┴.) was less than 2.2×10-4 in both sets of GaAs samples. Ion channeling, however, revealed a large tetragonal strain of 3.5×10-3 (ε┴ = 1.7×10-3) in the thinner (140 nm) CaF2 buffer layers. By doing ion channeling with high energy (2.5 MeV) protons, it was possible to determine strain more accurately. Using this technique, we were able to set an upper limit for the tetragonal strain of 2.5×10-4 in both the GaAs (which implies ε┴ < 8×10-5 and CaF2 (ε┴ < 1.5×10-4) layers for the thicker (380 nm) CaF2 buffer layer structure. These results are in good agreement with the strain predicted from previous strain measurements of CaF2 epitaxial layers on Si.
Surface Stress Effect on the Elastic Moduli of Superlattice Thin Films
Authors: Cammarata R. C. , Sieradzki K. , Streitz F. H. 
Published: March 2011

AbstractA thermodynamic model is presented which predicts a significant sample size effect on the elastic moduli of superlattice thin films possessing small bilayer repeat lengths. Owing to the presence of incoherent (incommensurate) interfacial stresses, biaxial in-plane strains are created which are approximately inversely proportional to the bilayer repeat length Λ. When Λ is of the order of 1 nm, these strains can be of the order of 1%, inducing nonlinear elastic behavior. This model is able to explain in a quantitative way the existence of a “supermodulus” effect in certain metallic superlattices.
Multilayered Metallic Thin Films Prepared by Dual-Bath Electrodeposition
Authors: Ross C.A. , Goldman L.M. , Spaepen F. 
Published: March 2011

AbstractElectrodeposition is a fast and relatively inexpensive method for making metal multi-layered films. We present a dual bath electrodeposition technique capable of producing crystalline Ni/amorphous NiPx multilayers with repeat lengths of 20Å and above, of sufficient quality to give several low-angle x-ray reflections. The compositional and structural modulations of the films are analysed using x-ray diffraction and microscopy, and the effects of deposition parameters, such as the current density, are examined.
A Systematic Method for Extracting Structural Parameters from Low Angle X-Ray Reflectivity Measurements on Multilayers
Authors: Goldman L.M. , Atwater H.A. , Spaepen F. 
Published: March 2011

AbstractX-ray diffraction is one of the main methods of determining the structure of multilayers. Low angle reflectivity measurements are particulary useful for multilayers containing polycrystalline or amorphous constituents, and for obtaining specific structural data. We present a method based on both kinematic and dynamic scattering calculations, and use it to extract specific structural parameters such as the roughness or diffuseness of the external surface, the thickness of the constituent layers, and the roughness or diffuseness of the internal interfaces. Results are given for a sputtered A1/A12O3 multilayer.