bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metallic Glasses and Metastable Crystalline Phases Produced by Picosecond Pulsed Laser Quenching
Authors: Lin C.-J. , Spaepen F. 
Published: March 2011

ABSTRACTThe mechanism of ultrafast cooling (1012K sec−1) by picosecond pulsed laser irradiation is reviewed, and it is demonstrated that only partitionless transformations can occur. The glass formation range in a number of binary systems is reviewed, demonstrating that many glasses can be formed below the To-line. The formation of metastable crystalline alloys in the Fe-B, Ni-Nb, Cu-Co and Au-Co systems is reported.
Growth and Surface Morphology of Thin Silicon Films Using an Atomic Force Microscope
Authors: Hegde Rama I. , Chonko Mark A. , Tobin Philip J. 
Published: March 2011

ABSTRACTThe growth and surface morphology of thin LPCVD silicon films were investigated with an atomic force microscope (AFM). Silicon films of 30 nm thicknesses were deposited on SiO2 using SiH4 at four different temperatures between 550 °C and 625 °C. These AFM results permitted visualization of silicon surface granularity, roughness, and the transition with temperature from amorphous to crystalline structure between 550 °C and 580 °C. The surface of the amorphous film deposited at 550 °C is very smooth and the film is continuous physically, while the film formed at 580 °C appears crystalline, rough and porous. At 600 °C and 625 °C the films are fully crystalline. For these higher temperature films surface roughness and the average grain size decreased significantly compared to 580 °C film. Crystallinity and film continuity were further examined by x-ray diffraction (XRD) and cross-sectional TEM measurements.
Adatom Concentration Profiles on Simulated Vicinal Surfaces During Epitaxial Growth
Authors: Shitara Tomoya , Suzuki Takashi , Vvedensky Dimitri D. , Nishinaga Tatau 
Published: March 2011

ABSTRACTConcentration profiles of surface atoms have been obtained from Monte Carlo simulations of epitaxial growth with anisotropic nearest-neighbor bonding on two different vicinal GaAs(001) surfaces which are misoriented toward [110] (denoted asA) and [110] (denoted asB). These profiles are compared with predictions based upon the original Burton-Cabrera-Frank (BCF) theory and with a modified BCF theory which accounts for the fact that all atoms, not simply free adatoms, can participate in surface diffusion. On both surfaces the modified BCF equation provides a more accurate description of the adatom concentration profiles than that obtained using only the free adatom concentration. This is due to step detachment processes which leads to an effective source of free adatoms that is not taken into account in the original BCF approach. Above the temperature where the growth becomes dominated by step advancement, the curvature of the concentration profile of potentially active atoms on both surfaces are similar but the concentrations differ due to the difference of the capture efficiency of the two types of step edges.
Correlation Length Scaling During the Early Stages of Epitaxial Growth
Authors: Haider Niaz , Wilby Mark R. , Vvedensky Dimitri D. 
Published: March 2011

ABSTRACTWe have calculated the height-height correlation function by means of Monte Carlo simulations of a solid-on-solid model. These simulations reveal that the position and sizes of the islands formed during the first half-monolayer are highly correlated, a feature which has also been noted in recent x-ray studies of growth by OMCVD. This morphology results in the emergence of a characteristic length,ℓ, in the correlation function, which is found to obey the scaling lawℓ = (D)/J)γ, whereDis the diffusion length, andJis the deposition flux. The value of the exponent γ varies with coverage and depends on the growth conditions.
The Characteristics of LPCVD Aluminum Films: Nucleation and Selectivity
Authors: Lee K.-I. , Kim Y.-S. , Joo S.-K. 
Published: March 2011

ABSTRACTGrowth kinetics of CVD Al films using TIBA(Tri-IsoButyl-Aluminum) as a source material were investigated. Nucleation activation energy of aluminum on the silicon substrate was determined to be 3.2 eV for the first time in this work. It turned out that selectivity between Si and SiO2 was very sensitive to the substrate temperature during deposition, which could be well explained from the nucleation activation energy derived in this work. It was found that the surface topology of aluminum films could be improved by reduction of nucleation activation energy through pre-treatment of the substrate.
Growth Kinetics of Molecular Beam Epitaxy on Non-Singular Surfaces
Authors: Egler J. F. , Otsuka N. , Mahalingam K. 
Published: March 2011

ABSTRACTGrowth kinetics on non-singular surfaces were studied by Monte Carlo simulations. In contrast to the growth on singular and vicinal surfaces, the sticking coefficient on the non-singular surfaces was found to decrease with increase of the surface roughness. Simulations of annealing processes showed that surface diffusion of atoms leads to a stationary surface roughness, which is explained by multiple configurations having the lowest energy in the non-singular surface.
A Study of MOCVD-Grown Gallium Nitride Nucleation Layers on Sapphire
Authors: Estes Wickenden A. , Wickenden D. K. , Kistenmacher T. J. , Ecelberger S. A. , Poehler T. O. 
Published: March 2011

ABSTRACTNucleation layers of GaN have been deposited in an MOCVD reactor on (0001) sapphire, over a range of temperatures and layer thicknesses, using either N2 or H2 carrier gas. The layers have been found to be continuous, textured films as deposited at low temperatures (600°C), but to reorder upon annealing, segregating into nucleation sites which exhibit the normal heteroepitaxial relationship with the sapphire substrate.
Direct Observation of a Surface Phase Transition by hot Tunneling Microscopy
Authors: Hwang Ing-Shouh , Golovchenko Jene A. 
Published: March 2011

ABSTRACTWe study a reversible phase transition of one monolayer of Pb on a Ge(l11) surface over a range of temperature from below to above the transition temperature (∼175°C) with the tunneling microscope. The high temperature l×1 phase is a ordered monolayer l×l 2D solid. Below the transition temperature, Pb atoms are displaced from their ideal T1 positions to form trimers with periodicity.
Defect Characterization of InAs Films Grown by Two-Step MOCVD on (100) InP Substrates
Authors: Ballal A. K. , Salamanca-Riba L. , Partin D. L. 
Published: March 2011

ABSTRACTIn this paper we investigate the defect morphology and misfit strain in InAs films grown on (100) InP substrates using two-step metal organic chemical vapor deposition (MOCVD). High quality InAs films were obtained despite the 3.2% lattice-mismatch between the InAs film and the InP substrate. Cross-sectional and plan-view transmission electron microscopy has been used to characterize the ∼3μm thick InAs films. Almost all the lattice mismatch is accomodated by an orthogonal array of pure edge Lomer dislocations which are favored over the 60° type since they are more efficient in relieving misfit strain. In addition to misfit dislocations, threading dislocations were observed propagating through the film. Most of the threading dislocations were 60° type dislocations along the < 211 > and < 110 > directions on inclined {111} planes. The threading dislocations originate from island coalescence during film growth. High resolution electron microscopy shows the epitaxial relationship between the film and the substrate and reveals an abrupt and sharp interface with periodic dislocation cores.
Novel Glide Planes in Epitaxially Grown Semiconductors
Authors: Albrecht M. , Strunk H. P. , Hansson P. O. , Bauser E. 
Published: March 2011

ABSTRACTThe accommodation of misfit stresses during heteroepitaxial growth of Ge0.85Si0.15 on Si(110) from In solution is studied by transmission electron microscopy. The regular misfit dislocation network forms at the interface and can be explained by glide of dislocations in a secondary a/2<110>{311} glide system. The occurrence of this secondary glide system is analyzed in terms of a mechanical equilibrium analysis that includes a frictional force due to a static Peierls barrier.
Internal Stresses and Damping in Ni/Cu Multilayered Thin Films
Authors: Su C. M. , Oberle R. R. , Cammarata R. C. , Wuttig Manfred 
Published: March 2011

ABSTRACTThe internal stresses and anelastic properties of an electrodeposited Ni/Cu multilayered membrane as measured dynamically using a vibrating membrane method are reported. Our results indicate that the as-deposited membrane has a high internal stress approaching the yield strength. Due to the accuracy of the experimental method, the damping of the multilayered membrane can be measured in the presence of the high internal stresses. It is shown that the relatively large damping capacity exhibited by the multilayered film is different from classical damping associated with the modulus defect, and may be related to an interfacial relaxation effect such as sliding.
Analysis of the Enhanced Growth Rate of Silicon-Oxide Layers in the Thin Regime by Incremental Growth
Authors: Ajuria Sergio A. , Kenkare Prashant U. , Nghiem Anh 
Published: March 2011

ABSTRACTSilicon oxidation kinetics in the thin regime are studied by a unique method in which thermally grown as well as densified CVD-deposited oxides are incrementally reoxidized and measured. Strikingly higher oxidation rates are obtained through deposited oxides, as compared to thermal oxides, suggesting that oxidations are suppressed after an initial layer is grown rather than enhanced during initial layer formation. We show that these findings tend to support initial oxidation models based on stress.
Microstructural Evolution of Multilayered Oxide Scales on Stainless Steels
Authors: Basu S. N. , Nath D. , Tebbets J. 
Published: March 2011

ABSTRACTSi containing stainless steels form complex oxide scales during high temperature oxidation at 900°C. These scales consist of an outer iron chromium manganese spinel layer, an intermediate Cr2O3 (chromia) layer and an inner SiO2 (silica) layer. During isothermal oxidation, alloys exhibit minimum weight gain when the inner silica layer is continuous, due to its effectiveness as a diffusion barrier. This continuous silica scale can be formed in a short time only by a combination of fine alloy grain size and high silicon content. However, formation of a continuous silica layer may lead to scale spallation on cooling, thus having a deleterious effect on the oxidation resistance of the alloy.
Metastable Sic and SiGeC Alloys by Carbon Implantation and Solid Phase Epitaxy
Authors: Strane J. W. , Edwards W. J. , Mayer J. W. , Stain H. S. , Lee B. R. , Doyle B. L. , Piorauz B. T. 
Published: March 2011

ABSTRACTWe demonstrate the formation of metastable Si1-yCy and Si1-y-xGexCy alloys by C ion implantation and solid phase epitaxial regrowth. Carbon was introduced into Si and SiGe layers by 5, 12 and 25 keV implants to achieve nearly uniform profiles of 0.7 and 1.4 at.% C. The 0.7 at.% C specimens exhibit the highest quality epitaxial layers after SPE regrowth, whereas in higher C concentration specimens solid phase regrowth was impeded. The localized vibrational mode of C occupying substitutional lattice sites in the diamond lattice provides a signature of the metastable phase and is used to monitor the loss of stability due to precipitation of silicon carbide. The Sic and SiGeC alloys retained substitutional carbon during 30 minute isochronal anneals up to 850°C.
The Determination of Step Heights on the Non-Uhv Heat-Treated MgO (100) Surface by CBED
Authors: King Simon , McKernan Stuart , Barry Carter C. 
Published: March 2011

ABSTRACTConditions are established whereby step heights may be measured in the acid-washed and air-annealed MgO single-crystals currently employed as substrates for pulsed-laser-deposition. Preliminary data indicates that the steps are typically a few nanometers in height.
Time-Resolved Optical Studies of Amorphous CoSi Thin-Film Crystallization
Authors: Libera M. , Kim T. , Siangchaew K. , Clevenger L. , Hong Q. 
Published: March 2011

ABSTRACTTime-resolved reflection and transmission measurements during heating are coupled with transmission electron microscopy (TEM) to study the crystallization of amorphous 75nm Co49Si51 films. The reflection decreases and the transmission increases upon crystallization. Optical data are converted to a measure of the fraction crystallized, χ=χ(T,t). A Kissinger analysis gives an activation energy for crystallization of 1.1 eV. TEM analysis of films crystallized in-situ show they are principally CoSi2 with a small amount of CoSi2. These results are being used for kinetic modelling of crystallization of amorphous Co-silicide films for potential use in Si mosfet and bipolar technologies.
A Model for Double Positioning Twin Formation in Cubic SiC on Noncubic SiC Substrates
Authors: Yoo Woo Sik , Beetz. Charles P. , Chien Fen-Ren , Nutt Steven R. , Kimoto Tsunenobu , Matsunami Hiroyuki 
Published: March 2011

ABSTRACTAs an attempt to explain polytype formation and crystal growth of SiC we propose an electrostatic model in which electrostatic Coulomb force is considered as an interatomic force. The dependence of surface potential on the stacking sequence of atoms in substrates was investigated, and the growth simulation was tried considering the energetic balance under various interaction lengths.The model predicts the double positioning twin formation and the difference in area between twins in cubic 3C-SiC growth on hexagonal 6H-SiC and rhombohedral 15R-SiC substrates. The prediction was experimentally tested by simultaneous chemical vapor deposition growth on basal planes of 6H-SiC(0001) and 15R-SiC(0001). Polytype and interface structure of both specimens were investigated by reflection high energy electron diffraction (RHEED) and high resolution transmission electron microscopy (HRTEM).
Desorption Kinetics of Indium at the InAs/GaAs(001) Heterointerface
Authors: Kaspi Ron , Evans Keith R. 
Published: March 2011

ABSTRACTDesorption Mass Spectrometry (DMS) is used to monitor In desorption kinetics at the InAs/GaAs (001) heterointerface. In incorporation is determined to be significantly affected by temperature, surface reconstruction, and the V/III flux ratio. It is shown that the onset of the As-stabilized (2×4)-to-In-stabilized (4×2) surface phase transition is surface stoichiometry dependent, and that both the As-stabilized and the In-stabilized surface exhibit first order desorption behavior. Desorption activation energy of In from the (2×4) and the (4×2) surface is measured. In addition to an In-stabilized regime, an In-accumulated regime is identified by its deviation from first order desorption behavior.
GAS-Phase Decomposition Kinetics of MOVPE Precursors in a Counterflow Jet Reactor
Authors: Safvi S. A. , Mountziaris T. J. 
Published: March 2011

ABSTRACTA new reactor for studying the purely homogeneous thermal decomposition of organometallic precursors used in the Metalorganic Vapor Phase Epitaxy (MOVPE) of semiconductors is presented. The idea is based on the use of a counterflow jet configuration with one jet being heated and the other unheated. The heated jet contains pure carrier gas (typically hydrogen or nitrogen), while the unheated jet contains vapors of an organometallic species diluted in the same carrier gas. Under appropriate operating conditions, decomposition of the organometallic species takes place near the stagnation plane where the hot jet collides with the cool jet. Since the reactions occur in the gas phase and away from hot walls, purely homogeneous kinetics can be obtained. Such a counterflow jet reactor was designed for studying the thermal decomposition of tertiary-butyl-arsine (TBA), t-C4H9AsH2, a very promising precursor for MOVPE of GaAs films. Two-dimensional finite element simulations of transport phenomena and kinetics have been used to identify optimal operating conditions. An experimental system was constructed and capillary-sampled mass spectroscopy at the stagnation plane was used to study the thermal decomposition of TBA in nitrogen at a total pressure of 252 Torr. Gas-chromatography of the effluent gas stream was employed for positive identification of the hydrocarbon byproducts. The results indicate the existence of two major decomposition routes: (1) A low activation energy pathway producing isobutane AsH, and (2) a higher activation energy, β-hydride elimination pathway producing isobutene and arsine.
The Adsorption and Decomposition of Gallane Adducts on GaAs (100)
Authors: Foord J. S. , Wee A.T.S. , Singh N. K. , Whitaker T. J. , O'Hare D. 
Published: March 2011

ABSTRACTThe adsorption and decomposition of GaH3NMe3 and GaH3PMe3 on GaAs (100) has been investigated using XPS, TDS and molecular beam techniques. Both precursors react in a similar way with the adsorbed layer formed at low temperatures decomposing as the temperature is raised to produce metallic Ga, gaseous gallium hydride(s) and adsorbed hydrogen and the Lewis base, which also undergo desorption. Molecular beam measurements show that both compounds exhibit similar decomposition kinetics and decompose more readily than the aluminium analogues. The results indicate that the site-blocking effects, which prevent the low temperature decomposition of alane adducts, are less significant for the gallane compounds.
Metallisation and Silicidation of Porous Silicon
Authors: Aylett Bernard J. , Earwaker Lyndsay G. , Keen John M. 
Published: March 2011

ABSTRACTThin films of cobalt, rhenium, or cobalt silicide have been deposited down the pores of porous silicon layers, using HCo(CO)4, HRe(CO)5, and SiH3Co(CO)4as precursors in a Chemical Vapour Infiltration and Decomposition (CVID) technique.
Copper Films Prepared by Metal Organic Chemical Vapor Deposition (MOCVD) Process Using Copper (Acetylacetonate) and Water Vapor as Reactants: The Impact of Water Vapor
Authors: Chang Yu-Neng 
Published: March 2011

ABSTRACTBy using the strong reductive potential of copper acetylacetone (Cu(acac)2) when Cu(acac)2) was thermally decomposed, copper metal films were prepared by metal organic chemical vapor deposition (MOCVD) process using sublimed Cu(acac)2 vapor and water vapor as reactants, at one atmosphere pressure. According to thermodynamic calculations, Cu films could be prepared by MOCVD process with a high ratio of partial pressures for water vapor and Cu(acac)2 vapor (PH2O/Pcu(acac)2>30) In this paper, the impacts of MOCVD processing parameters such as watervapor partial pressure, total carrier gas flow rate, and precursor partial pressure on film composition and microstructure were investigated. Deposition temperature is the primary processing parameter affecting film stoichiometry. In a specific deposition temperature window, from 370°C to 400°C, polycrystalline Cu films with Cu [111] preferential orientation were deposited. ER and XRD results indicated that films deposited at temperature lower than 350°C contain copper oxide phase with poor crystal structure. By comparing the values of X-ray Auger Electron Spectroscopy (XAES) and Auger parameter (αAu) from photoelectrons of Cu films and standards from reference compounds, die principle oxidation state of copper in these films was determined as Cu(0). The deposition results indicated that a water vapor partial pressure above 10 torr is necessary to produce Cu films. As indicated by SEM, Increasing the carrier gas flow rate, above 600 sccm, can reduce the average temperature profile in the thermal boundary layer above the substrate surface, retard the gas phase reaction rate, presumably eliminate the homogeneous nucleation, and deposit smooth Cu films.
Surface and Reactor Effects on Selective Copper Deposition from Cu(hfac)tmvs
Authors: Norman John A. T. , Roberts David A. , Hochberg Arthur K. 
Published: March 2011

ABSTRACTThe selectivity of OMCVD copper films grown at 160°C/500 mTorr from the volatile liquid precursor Cu(hfac)tmvs was evaluated for various commercial 6” wafers patterned with either TiN/SiO2 or TiN/Si3N4. By processing wafers “as received”, only thermal grown SiO2 consistently resisted metallization, allowing copper films up to 1.5μ thick to be grown on TiN. For SiO2, films containing H2O, especially from PECVD, only blanket deposition was observed. However, by a utilizing simple thermal predeposition dehydration some of these SiO2 films were conditioned to give selective deposition.
Nucleation of Tungsten on Titanium Nitride with Hydrogen Reduction of Tungsten Hexafluoride
Authors: Srinivas D. , Foster R. , Marcus S. , Arora R. , Rebenne H. 
Published: March 2011

ABSTRACTIn this work, a hydrogen (H2) reduction process has been developed which gives tungsten (W) nucleation on titanium nitride (TiN) adhesion layers with a very short incubation time, eliminating the need for a silane (SiH4reduced seed layer. The nucleation was found to be strongly dependent on the following factors: temperature of the substrate, total pressure in chamber, and gas introduction sequence into the reactor. Theenhanced nucleation rate has been explained based on two competing reactions: dissociation of H2, and formation of titanium subfluorides on the TiN surface.
CBE Growth of InP with Triethylindium and Metalorganic Phosphorous Precursors: Bisphosphinoethane and Tertiarybutyl-Phosphine
Authors: Chin Albert , Hersee Steve , Martin Paul , Mazurowski John , Ballingall James , Glass J. A. , Spencer James T. 
Published: March 2011

ABSTRACTTwo metallorganic phosphorous precursors, bisphosphinoethane (BPE) and tertiarybutyl phosphine (TBP), were studied. For indium phosphide (InP) grown using BPE, the measured room temperature and 77K Hall mobilities were 4,200 and 22,000 cm2/Vs, with carrierdensities 5.7E15 and 4.0E15 cm−3, respectively. For InP grown using TBP, the measured room temperature and 77K Hall mobilities were 4,400 and 26,000 cm2/Vs, with carrier densities 6.4E15 and 5.1E15 cm−3, respectively. An impurity build-up at the substrate interface is responsible for the relatively low mobility in the adjacent epitaxial layers. SIMS analysis showed that S and Si are the primary impurities measured in films grown with BPE and TBP, respectively; impurity concentrations increasedwith cracking temperature. The full width at half maximum (FWHM) of donor bound exciton peaks measured by 2.2K photoluminescence for InP grown by BPE and TBP were 0.84 and 1.28 meV, respectively.
Chemical Vapor Deposition of SiC from Silacyclobutane and Methylsilane
Authors: Johnson A. D. , Perrin J. , Mucha J. A. , Ibbotson D. E. 
Published: March 2011

ABSTRACTThe kinetics of SiC deposition has been studied over the temperature range 650–1050 ° C using the single-source reagents silacyclobutane (SCB) and methylsi-lane (MeSiH3 ) whose decomposition supplies the isomeric film-forming precursors H2Si = CH2 and HSiCH3, respectively. Thermal decomposition has been monitored by mass spectrometry and the SiC thin films characterized by scattering spec-trometry (RBS & ERD), FTIR spectroscopy and X-ray diffraction. Deposition rates from the two are comparable, with activation energies of 41 kcal/mole and 53 kcal/mole for SCB and MeSiH3 decomposition, respectively. Silacyclobutane deposits C-rich material lower temperatures, while SiC deposited from MeSiH3 is Si-rich at all temperatures. A mechanism for SiC CVD is proposed that is consistent with the observed kinetics and products.