bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cosio2 Formation on Strained GexSi1−x Layers BY Co/GexSi1−x Thermal Reaction
Authors: Ridgway M.M. , Elliman R.R. , Pascual R. , Whitton J.J. , Baribeau J.-M. 
Published: March 2011

ABSTRACTThe formation of CoSi2 on Ge.17Si.83 layers by Co/Ge.17Si.83 thermal reaction nas been studied with a variety of analytical techniques. Co films deposited on strained Ge.17Si.83 layers were annealed at 600°C for 0–240 min. Following 240 rain annealing, the reacted surface layer was composed of CoSi, CoSi2 and GexSi1-x precipitates (the latter probably rich in Ge) as identified with transmission electron microscopy, x-ray diffraction and/or Raman spectroscopy. Lateral phase non-uniformity was evident with both transmission and scanning electron microscopy. For samples annealed with and without an evaporated Co film, enhanced relaxation of the underlying Ge.17Si.83 layer was apparent in the former.
Stability of Nanometer-Size Si Crystals in Amorphous Si Thin Films under Ion Irradiation
Authors: Yang Chih M. , Atwater Harry A. 
Published: March 2011

ABSTRACTIn this paper we discuss the size-dependent shrinkage rate of nanometer-size Si crystals in amorphous Si thin films during ion irradiation. We obtain shrinkage rate of nanometersize crystals at low temperature under ion irradiation by studying the evolution of the crystal size distribution using transmission electron microscopy. Our results indicate that crystals less than 10 nm in diameter decrease in size faster than larger crystals under ion irradiation. In addition, we fit our data to a capillary model for growth of Si crystals in amorphous Si under ion irradiation.
Amorphization of Zr/Ni Bilayers by Ion-Beam-Mixing
Authors: Jagelski Jacek , Thome L. , Kopcewicz M. 
Published: March 2011

ABSTRACTThe amorphization process induced by ion-beam-imxing was studied for the Zr/Ni bilayer system by means of the RBS/channelling and CEMS techniques. The number of atoms mixed per one incident atom was found to be the same for σ100 K and 300 K irradiations, whereas it was increased by the factor of 2.5 for 500 K irradiation what indicates, that the change in the mixing mechanism occurred above room temperature. The results show that amorphization of the Zr/Ni system is controlled by the number of mixed atoms and depends on the irradiation temperature. A change in CEMS spectra was observed at σ770 K what suggests that recrystallization of the amorphous phase occurs at this temperature.
Electron Irradiation Induced Crystallization of Amorphous Al2O3 Films on Silicon Substrates
Authors: Liu J. , Barbero C. J. , Corbett J. W. , Rajan K. , Leary H. 
Published: March 2011

ABSTRACTAn in situ study of electron beam irradiation induced amorphous–to–crystalline transformation of Al2O3 films on silicon substrates has been carried out using transmission electron microscopy. Trigonal α–Al2O3 crystallites can be observed for electron beam dose rates larger than 10 mA/cm2. It is found that the nucleation and growth processes dominate near the Al2O3–Si interface. The possible effect of the silicon substrate on the growth of Al2O3 crystallites is considered.
Time Resolved X-Ray Diffraction Study of the Transformation Kinetics of TiSi2-C49 in Amorphous Si/Ti Multilayers
Authors: Sariel J. , Chen Haydn , Jongste J. F. , Radelaar S. 
Published: March 2011

ABSTRACTAmorphous Si/Ti multilayers transform at high temperatures (above 700°C) to TiSi2-C54. This phase is important for microelectronics applications because of its low resistivity, stability up to 900°C, and compatibility with silicon processing. However, an unfavorable metastable TiSi2-C49 phase is usually formed at lower temperatures. Thus, an understanding of the C49 phase formation kinetics is useful to the device processing strategy. The kinetics of the transformation of TiSi2-C49 phase can be characterized as a process of nucleation and growth, using the well known Johnson Mehl Avrami (JMA) equation. In the present work the formation kinetics of the C49 phase has been studied by an in situ x-ray diffraction technique. Isothermal annealing in vacuum was done at four temperatures, in the range of 275"C to 310°C. A position sensitive detector (PSD) was used to simultaneously collect the diffracted beams of (131) and (150) peaks of the C49 phase. From the data, the Avrami exponent, n, was determined to be 2.0±0.1. The reaction rate constant k follows a familiar Arrhenius-type equation with a measured activation energy of 2.5eV. Comparison of our x-ray results with kinetic data obtained by other means will be discussed.
Phase Transformation Kinetics of TiSi2
Authors: Mann R.R. , Clevenger L.L. , Hong Q.Q. 
Published: March 2011

ABSTRACTThe microstructure and kinetics of the polymorphic C49 to C54-TiSi2phase transformation have been studied using samples prepared as in self-aligned silicide applications. For C49-TiSi2thin films formed at temperatures of 600°C and 625°C on (100) single-crystal silicon substrates, the effective activation energy was 5.6 ± 0.3 and 5.7 ± 0.08 eV, respectively, for this phase transformation carried out in the temperature range of 600°C to 700°C. The transformation process was observed to occur by nucleation and growth of the orthorhombic face-centered (C54) phase from the as-formed orthorhombic base-centered (C49) phase.
Equilibrium Shape of CoSi2in Silicon
Authors: Adams D.D. , Yalisove S.S. , Eaglesham D.D. 
Published: March 2011

ABSTRACTThe energetics associated with the formation of CoSi2have been investigated by using the equilibrium shape of isolated precipitates. Two types of precipitates were studied: CoSi2equilibrated at the Si surface and CoSi2equilibrated within the Si lattice. CoSi2precipitates form by facetting along {111} and {1100} planes in Si. Using a reverse Wulff approach, a ratio of interfacial free energies of γ{100} / γ{111) has been measured to be 1.43 ± 0.07.
Reaction Rate Kinetics and Film Textures of Palladium Silicide Formed on Hydrogenated Amorphous Silicon
Authors: Manning N. R. , Chen Haydn , Abelson J. R. , Allen L. H. 
Published: March 2011

ABSTRACTThe reaction rate kinetics of the thin film solid-state reaction between 120 nm of Pd and 100 or 300 nm of a-Si:H(18at%) to form Pd2Si were studied in situ using x-ray diffraction and four-point probe resistivity measurements during isothermal annealing. These two techniques yielded activation energies and prefactors of Ea=1. 36±:0.11 eV with ko=4.29 cm2/sec for the x-ray diffraction experiments; and Ea=0.97±0.22 eV with ko=3.42x10-4 cm2/sec for the resistivity measurements. The activation energy and prefactor obtained from the c-Si substrate of the resistivity measurements yielded Ea=l.41±0.31 eV and ko=10.6 cm2/sec. Comparisons showed that the silicide formed from the a-Si:H reacted approximately 1.4 times faster than the silicide formed from the c-Si in the same sample, but three times faster than silicide formed on pure c-Si(111). The crystalline texture and grain size of the metal and silicide films were examined.
Simultaneous Occurrence of Multiphases in the Interfacial Reactions of Ultrahigh Vacuum Deposited Ti, Hf and Cr Thin Films on (111)Si
Authors: Hsieh W.W. , Lin J.J. , Wang M.M. , Chen L.L. 
Published: March 2011

ABSTRACTSimultaneous occurrence of multiphases was observed in the interfacial reactions of ultrahigh vacuum deposited Ti, Hf and Cr thin films on (111)Si by high resolution transmission electron microscopy in conjunction with fast Fourier transform diffraction analysis and image simulation. For the three systems, an amorphous interlayer as well as a number of crystalline phase were found to form simultaneously in the early stages of interfacial reactions. The formation of multiphases appeared to be quite general in the initial stages of interfacial reactions of UHV deposited refractory thin films. The results called for a reexamination of generally accepted “difference” in reaction sequence between bulk and thin film couples.
Phase Transformation of Mo and W over Co OR Its Alloy in Contact with Si
Authors: Yang Fann-Mei , Chen Mao-Chieh 
Published: March 2011

ABSTRACTW or Mo directly deposited on Si cold substrate by electron-beam gun at a base pressure of 10-6 torr is not able to form silicide even annealed at 900 °C in either N2 or H2 ambient. We present an easy way that Mo and W silicides can be formed on the same depositing and annealing conditions with the help of an intervened layer of cobalt or its alloy. Investigation was made on various metallizations of Mo (or W)/Co/Si, W/Co-Mo/Si, and Co/Mo/Si in normal flowingnitrogen or in H2 ambient at various temperatures. In the systems of Mo (or W)/Co/Si and W/Co-Mo/Si, the overlying Mo (or W) can be transformed into silicide at 900 °C, while in the Co/Mo/Si system, where stable Co-Mo compounds are formed in advance, no silicide can be formed. Why silicide is formed in preference to metal oxide in N2 environment at higher temperature is based on Ellingham diagram.
Transmission Electron Microscopy Study of Thick Copper-304 Stainless Steel Multilayers
Authors: Wall M. A. , Barbee T. W. , Weihs T. 
Published: March 2011

ABSTRACTThick (10 to 25 μm), free-standing, equal layer thickness, Copper(Cu)-304 Stainless Steel(SS) multilayer foils, having periods of lnm to 100 nm, synthesized by magnetron sputter deposition, have been examined by plan view and cross-sectional transmission electron microscopy. Multilayer growth morphology, individual layer structure and crystallographic phase orientation relationships were characterized in this study. Electron Energy Loss filtered imaging of a 20 nm period multilayer cross-section was also performed and showed that nickel had diffused into the Cu layers from the SS during synthesis. X-ray powder diffraction scans were performed and analyzed. A pure deposit of 304SS was synthesized and had a metastable BCC structure. Multilayer samples having periods of 20 nm were found to have a coherent layered Cu(FCC)- SS(FCC) structure. At larger periods (50 & 100 nm) a bimodal Cu(FCC)-SS(FCC & BCC) structure was formed. These observations show that the 304SS will grow with a metastable BCC structure when sputter deposited. When layered with Cu(FCC) the 304SS has its equilibrium FCC structure at layer thicknesses up to 10nm as a result of epitaxy with the copper. At larger SS layer thicknesses the SS appears to locally transform to the metastable BCC structure during synthesis, refining the grain structure of the depositing SS layer and the subsequent Cu layer. This transformation significantly increases the strength of the larger period multilayer.
Direct Deposition Reactions Between Nickel and Silicon Substrates
Authors: Zhang Lin , Ivey Douglas G. 
Published: March 2011

ABSTRACTSilicide formation through deposition of Ni onto hot Si substrates has been investigated. Ni was deposited onto <100> oriented Si wafers, which were heated up to 300°C, by e-beam evaporation under a vacuum of <2x10-6 Torr. The deposition rates were varied from 0.1 nm/s to 6 nm/s. The samples were then examined by both cross sectional and plan view transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy and electron diffraction. The experimental results are discussed in terms of a new kinetic model.
Hydrogen Evolution and Interface Reaction of Cu Thin Film on a-Si:H
Authors: Bemardino L. , Achete Carlos , Freire F. L. 
Published: March 2011

ABSTRACTThe Cu/a-Si:H system has been studied by gas effusion method, elastic recoil detection analysis (ERDA), in situ sheet resistance measurements and scanning electron microscopy. Cu layers of 15 and 90 nm in thickness were deposited by e-beam evaporation onto 1 μm a-Si:H films produced by RF glow discharge on Si(100) substrates at 250 °C. The most important effects are observed in the effusion measurements, when pure a-Si:H samples and Cu/a-Si:H samples are compared. For the Cu/a-Si:H samples, three well-defined peaks are observed, one at very low temperature (T=200 °C), another at 380 °C and a high temperature peak at about. However, pure a-Si:H shows only one effusion maxima at 550 °C. The low temperature effusion peaks are directly correlated with steps increases in the sheet resistance measurements. The first one (T=200 °C) is due to the beginning of silicide formation. The H2 evolution at 380 °C is correlated to phase transition in the a-Si:H film. The hydrogen depth profiles obtained by ERDA and SEM observations are also used to describe the aspects of the Cu/a-Si:H interaction.
An Atomistic Study of Surface Vacancy Diffusion
Authors: Zhao L. , Najafabadi R. , Srolovtz D. J. 
Published: March 2011

ABSTRACTDiffusion of atoms and molecules on surfaces plays an important role in the growth of thin films. In the present study, the surface vacancy diffusion on Cu and Ni (100) and (111) planes is investigated via atomistic simulations. This investigation is performed using the Embedded Atom Method (EAM) interatomic potentials and the finite temperature properties are determined within the local harmonic and quasiharmonic frameworks. This study helps reveal fundamentals of surface vacancy diffusion in the thin film growth. Our results show that the vacancy diffusion is important on (100) surface but it is not the dominant diffusion mechanism on (111) plane.
The Influence of Deposition Pressure on the Incorporation of Target and Ambient Oxygen Into Laser Ablated Material
Authors: Tidrow M. Zhu , Tidrow S.S. , Wilber W.W. , Pfeffer R.R. 
Published: March 2011

ABSTRACTOxygen plays an essential role in the growth of a variety of oxides such as high-Tc superconductors, ferroelectrics, ferrites and dielectrics. The oxygen available for film growth during laser ablation can come from two sources: the target material and the ambient deposition atmosphere. The amount of oxygen incorporated from these two sources at room temperature has been investigated over a range of deposition pressures. Thiswas accomplished using 18O as a tracer during pulsed laser deposition of amorphous filmsfrom Cu and CuO targets. It was found that the total amount of oxygen incorporated by the amorphous films increases with chamber pressure up to approximately 35 mTorr. For pulsed laser deposition from the oxide target, the major fraction of the oxygen within the deposited material comes from the target. For the oxide target, the amount of oxygen incorporated from the ambient atmosphere is strongly pressure dependent with a maximum near 35 mTorr. These results are compared to earlier work with YBa2Cu3O7.
Phase Formation in a Wedged Au-Ag-Cu Multilayered Structure
Authors: Goldfarb I. , Zolotoyabko E. , Shechtman D. 
Published: March 2011

ABSTRACTAn advanced method for investigation of multicomponent systems is proposed. Thin wedged-shape films of pure components are subsequently deposited to form a multilayered structure with continuously-varying composition as a function of sample location, providing a large number of differently composed samples in one deposition run. Each sample is then subjected to various heat treatments, and phase content as well as the microstructure formed is under investigation.In this study an Au-Ag-Cu multilayered structure was sputtered at a room temperature onto 55 Formvar-coated Mo grids. The satellite-like X-Ray Diffraction (XRD) patterns of these samples revealed the formation of an artificial composition-modulated ternary superlattice, complete destruction of which was observed during heat treatments, where phase formation according to the ternary Au-Ag-Cu phase diagram took place.Several aspects of phase formation were analyzed using XRD, Electron Probe for Micro- Analysis (EPMA) in Scanning Electron Microscopy (SEM), and Scanning Transmission Electron Microscopy (STEM) combined with Selected Area Electron Diffraction (SAED), Digital X-Ray Mapping (DXM), Secondary Electron Mapping and EPMA methods.
Phase Selection During Interdiffusion in Ti-Fe Multilayered Films
Authors: Yan Z.Z. , Trudeau M.M. , Schulz R. , Bormann R. , Neste A.Van , Ström-Olsen J.J. 
Published: March 2011

ABSTRACTThe formation of the metastable bcc solid solution and the amorphous phase during interfacial reaction of elemental multilayers has been studied using X-ray diffraction. Different kinds of interfaces have been synthesized in order to investigate the influence of the interfacial structure on phase evolution during annealing. The amorphization is found to be dependent on the structure of the interface and the results are discussed in terms of the kinetics and thermodynamics of the Ti-Fe system which has been calculated by the CALPHAD method.
Solid State Amorphization in the Interfacial Reactions of Yttrium Thin Films on (111)Si
Authors: Lee T.T. , Chen L.L. 
Published: March 2011

ABSTRACTInterfacial reactions of ultrahigh vacuum deposited yttrium thin films on atomically clean (111)Si at low temperatures have been studied by both conventional and high resolution transmission electron microscopy, Auger electron spectroscopy and x-ray diffraction. A 10–nm–thick yttrium thin film, deposited onto (lll)Si at room temperature, was found to completely intermix with Si to form an 11–nm–thick amorphous interlayer. Crystalline Y5Si3 and Si were observed to nucleate first within the amorphous interlayer in samples annealed at temperatures lower than 200 °C. Epitaxial YSi2−x was found to be the only phase formed at the interface of amorphous interlayer and crystalline Si in samples annealed at temperatures higher than 250 °C. In as deposited 20– to 60–nm thick Y thin films on silicon samples, crystalline Y5Si3, Si, and YSi and a 2.5–nm–thick amorphous layer were found to be present simultaneously.
Crystallization of Amorphous Germanium in a Silver Germanium Layered System
Authors: Konno Toyohiko J. , Sinclair Robert 
Published: March 2011

ABSTRACTWe studied crystallization of amorphous germanium (a-Ge) induced in a Ag/a-Ge layered system, using in situ transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). Amorphous Ge was found to crystallize at about 270°C with the heat of reaction of 10±lkJ/mol. In situ TEM revealed that Ag grains migrate into the a-Ge phase leaving the crystalline Ge (c-Ge) phase behind. From this observation, we propose a model whereby the Ag provides the fastest path for the Ge atoms to diffuse from a-Ge to c-Ge phases.
Strain Relaxation During Growth Of Epitaxial Fe on Cu(O01)/MgO(001)
Authors: Daniels B. J. , Rensing N. M. , Bain J. A. , Brennan S. , Lairson B. M. , Payne A. P. , Clemens B. M. 
Published: March 2011

AbstractThe strain relaxation of sputter-deposited epitaxial Fe on Cu(001)/MgO(001) was observed in-situ for coverages of I to 200 equivalent monolayers of Fe. Grazing incidence x-ray scattering (GIXS) with synchrotron radiation allowed the precise determination of the in-plane strain in the Fe film. The highest observed elastic strain for the Fe was -10.3% which is in agreement with the lattice parameter mismatch between Fe and Cu for both (001)- and {211}-oriented growth. In-plane rocking curves revealed a bifurcation of the Fe(110) and Fe(220) peaks which is due to the rotation of islands to reduce strain energy. The angle of rotation of these islands was found to depend upon the amount of strain relaxation that had occurred in each island, in agreement with a simple theory for strain relaxation via the creation of a misfit dislocation network. The absence of Fe(200) intensity at small Fe thicknesses, coupled with out-of-plane symmetric and pole figure scans, suggest that Fe islands are tilted out of the plane of the sample about the Fe<110> axes by an angle consistent with Fe{211}-oriented growth. At larger thicknesses Fe(001) growth becomes dominant.
Stacking Fault-Like Fringes Along <010> Directions Observed in In0.52Al0.48 as Layers on the (100) Zone Axis
Authors: Peiró F. , Cornet A. , Morante J. R. 
Published: March 2011

AbstractIn this paper we present the TEM observations carried out on In0.52Al0.48As layers grown on InP at Tg+570°C. Plane view observations along the (100) zone axis show the existence of two types of contrast irregularity, with dark-bright fringes along the <010> directions and extinction for g +040 type reflections. One of these structures has been clearly related to precipitates at the lnAlAs/InP interface. The other, presents stacking fault-like fringes on the (100) plane, and the analysis of its traces on both (100) and (011) planes are presented. Despite the fact that its appearance resembles that of the structure linked to the precipitates, we will show that they are different phenomena and may even coexist.
X-Ray Diffraction Determination of Interface Roughness in GaAs/AlxGa1-xAs Multilayers
Authors: Nayak S. , Redwing J. M. , Kuech T. F. , Phang Y.-H. , Savage D. E. , Lagally M. G. 
Published: March 2011

AbstractX-ray diffraction has been used to quantify the interface roughness of GaAs/AlxGa1-xAs multilayers. X-ray measurements, both θ-2θ and rocking-curve analyses, quantitatively determine the correlated and random components of the interface roughness as well as the correlation length of the roughness along the interface. The multilayer structures of GaAs/Al0.3Ga0.7As and GaAs/AlAs differ substantially in the amplitude and correlation length of the interface roughness. The change in interfacial roughness is compared to that determined from low temperature photoluminescence (PL) measurements, the conventional measure of interface uniformity.
Effects of Growth Conditions and Substrate Orientation on the Properties of InSb
Authors: Biefeld R. M. , Baucom K. C. 
Published: March 2011

AbstractTwo new organometallic Sb sources, tris(dimethylamino)antimony (TDMASb), and tertiarybutyldimethylantimony (TBDMSb) are being investigated. The growth of InSb using TDMASb, or TBDMSb and TMIn was investigated over a temperature range of 350 to 475 °C using a range of V/III ratios, growth rates and pressures. Misoriented InSb substrates were also used for selected growth conditions The growth rates of lnSb using TMIn and either TDMASb or TBDMSb at temperatures <= 425 °C were proportional to both the TMIn flow rate and the temperature. The surface morphology of InSb grown using either TDMASb or TBDMSb was very rough for growth temperatures <=425 °C. This may be due to the complex decomposition mechanisms involved and the presence of methyl groups on the surface. Smoother backgrounds were generally found when using off axis substrates. The details of the defects observed on the surfaces were dependent on the type of misorientation and can be related to the atomic structure of the surface steps. Both n- and p-type InSb were grown using TBDMSb or TDMASb and TMIn with mobilities up to 68,990 and 7773 cm2/Vs, respectively, at 77 K. The mobility for lnSb using either TDMASb or TBDMSb was optimized by going to lower temperatures, pressures and V/III ratios. The opposite was true for surface morphology which improved with higher temperature, pressure, and V/III ratio. The growth of high mobility InSb with smooth surfaces at T< =425 °C was not achieved with TDMASb or TBDMSb and TMIn under the conditions investigated in this work.
Epitaxial CoSi2 Film Formation on (100) Si by Annealing of Co/Ti/Si Structure in N2
Authors: Ogawa Shinichi , lawrence M. , Dass A. , Fair James A. , Kouzaki Takashi , Fraser David B. 
Published: March 2011

AbstractCoSi2 was formed by annealing a multilayer strucure of sputter deposited Co / Ti / Si. The Ti was 1, 2 or 5 nm thick and the Co was 15 nm thick. The morphology of both the surface and the CoSi2 / Si interface was examined. For the sample that had 2 nm Ti layer, an epitaxial CoSi2 was formed with both a planar surface and a planar CoSi2 / Si interface. An amorphous Ti-Si-O layer was initially formed between the Co and the Si. Co then diffused through this layer and directly formed epitaxial CoSi2 on the Si<100>. No intermediate silicide phases of Co were observed.