bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nucleation and Heterointerface Structure of InAs Epilayers Grown on InP Substrates
Authors: Chandra Sekhar K. S. , Ballal A. K. , Salamanca-Riba L. , Partin D. L. 
Published: March 2011

ABSTRACTHeteroepitaxial growth of indium arsenide films on indium phosphide substrates is being actively pursued since the electronic properties of these films make them promising materials for optoelectronic and other high speed devices. The various structural aspects of the film that affect their electronic properties are structural defects like dislocations, film-substrate interface roughness and chemical inhomogeneities. In InAs films, electrons accumulate at the film-air interface, making surface morphology an important factor that decides the electronic properties. The InAs films used in this study were grown on InP substrates by metal organic vapor deposition, at different temperatures. A higher growth temperature not only resulted in poor surface morphology of the film, but also created a rough film-substrate interface. However, at all deposition temperatures, the film-substrate interfaces are sharp. At lower growth temperature, the interfaces were flat. Films grown at lower temperatures had good surface morphology and a flat and shaip heterointerface.
The Stress Driven Islands Formation in Epitaxial Films and Solid HE4 Films.
Authors: Grinfeld Michael A. 
Published: March 2011

ABSTRACTWe discuss the static and quasi-static problems appearing in the theory of morphological instability of interfaces. The approach has allowed to predict the corrugations in He4 films and to explain the dislocation-free Stranski-Krastanow pattern of epitaxial growth of thin solid films with the critical film thickness H = σμ/τ2 (σ is a surface energy, μ- the shear modulus, and τ - the mismatch stress). In this paper we discuss possible morphological patterns of corrugations and their changes which appear in result of the stress driven “rearrangement” destabilization of originally flat interfaces.
A Comparison of Magnetic Properties of Thin Films of Fe/GaAs(100) and Ni/MICA
Authors: Andrien Bruce , Miller David 
Published: March 2011

ABSTRACTA comparison between the morphology and magnetic properties has been made with thin films of Fe grown on GaAs(lOO) and of Ni grown on natural mica in the 10Å to 1000Å thickness range, in ultra high vacuum. The films are characterized in-situ by Auger spectroscopy and by an in-situ UHV M/H hysteresis loop tracer. If the films are thermally annealed, above 550°C for less than a few seconds, the film morphology changes. The Fe films form surface assembled clusters which are epitaxial with the GaAs substrate with diameters of order of the original average film thickness, while the Ni films grow large grains. The Auger signals show that the Fe clustering exposes the GaAs substrate while the Ni films are continuous and cover the mica substrate. In-situ adsorption studies of CO on the Ni films were consistent with the continuous nature of the Ni films. Hysteresis M/H curves are taken as a function of thickness and plots of coercivity versus film thickness or average cluster size shows a maximum near 100Å for both the Ni and the Fe films. The maximum is believed to be due to a trade-off between super-paramagnetism and magnetostatic forces, but with the grains in the Ni film playing the role of the clusters in the Fe film.
Microstructural Rearrangement in PZT(52/48) Thin Film Prepared By Reactive Cosputtering on Pt on Si(100)
Authors: Choo Woong Kil , Kim Kwang Young , Kim Hyo Jin , Kim Sung Tae 
Published: March 2011

ABSTRACTThe experimental conditions which render the exact stoichiometry of PZT(52/48) thin films deposited on Pt thin film on Si(100) by reactive cosputtering have been investigated. As-deposited PZT is amorphous containing α-PbO2microcrystallites. As annealing temperature increases, the amorphous PZT films crystallize into pyrochlore and perovskite with pseudo-cubic structure in sequence. The perovskite PZT annealed above 750 °C evolves into a phase of morphotropic phase boundary. In the perovskite PZT thin films, the leakage current increases with annealing time. Also, the dielectric constant increases with film thickness and annealing temperature, which is discussed in conjunction with PZT/Pt interfacial morphology.
Influence of Preferred Orientation in Indium Tin Oxide.
Authors: Taniguchi H. , Ushiro T. , Okamoto Y. , Akagi Y. , Koba M. 
Published: March 2011

ABSTRACTWe investigated the electrical and optical properties, the chemical composition, the surface morphology and the crystallinity of sputtered Sn-doped In2O3 films deposited on different substrate positions. Both the electric conductivity and the optical transparency are related to the free carrier density and moreover the preferred crystal orientation. The former relation is attributed to the Burstein-Moss effect and the latter suggests the Sn doping mechanism.
Surface Diffusion of Sulfur on Nickel (110) and the Effect of Carbon on the Diffusivity
Authors: Ladna Barbara , Birnbaum Howard K. 
Published: March 2011

ABSTRACTThe surface diffusion coefficient of sulfur on the (110) surface of nickel was determined at temperatures of 623, 673 and 723 K by measurement of surface diffusion profiles using an Auger Electron Spectrometer. A half-plane monolayer of segregated sulfur was used as a source and the analysis was done by a Boltzmann-Matano method. The activation energy for surface diffusion of sulfur was determined to be about 106 kJ/mol and pre-exponential Do to be about 6×10-3 m2/s from the Arrhenius plot of D versus 1/T. The presence of carbon on the surface of nickel was shown to decrease the surface diffusion of sulfur. Also, the mechanism of spreading from the half-plane source changed from a classic surface diffusion on clean surfaces to a linear mobility of the sulfur-carbon interface on surfaces covered with carbon.
Initial Growth of Metastable Titanium Disilicide at Amorphous Silicide/Crystalline Silicon Interface
Authors: Ma Z. , Allen L. H. , Lee S. 
Published: March 2011

ABSTRACTInitial stage of growth of metastable titanium disilicide (C49-TiSi2) was investigated by annealing Ti/doped polycrystalline Si bilayers deposited on oxidized Si wafers at 530°C and at a constant heating rate of 10°C/min. Morphological evolution of the C49-TiSi2 phase was studied by cross-sectional transmission electron microscopy (XTEM) and local chemistry was probed with a scanning transmission electron microscope (STEM) equipped with a nanoprobe. At the early stage, the C49-TiSi2 phase nucleates discontinuously along the amorphous silicide (a-TiSix )/crystalline Si (c-Si) interface and then exhibits simultaneous lateral growth and vertical growth. The results are interpretated using a model based upon preferential Si diffusion along interphase boundaries to the growth front.
Solid Phase Heteroepitaxy of Barium Ferrite on Sapphire
Authors: Parker Michael A. , Hylton T. L. , Coffey K. R. , Howard J. K. 
Published: March 2011

ABSTRACTA new process for the crystallization of amorphous films on chemically dissimilar substrates, solid phase heteroepitaxy (SPHE), is described. Unlike SPE in Si, it is found that the kinetics can be modeled by nucleation and multi-dimensional growth with Johnson-Mehl kinetics modified for the effects of a finite film thickness and nucleation initiated at the interface with the substrate.
Structure and Morphology of PD Overlayers on Epitaxial SNO2 Films Studied with the Atomic Force Microscope
Authors: Lad R. J. , Matthews M. J. , Antonik M. D. , Cavicchi R. E. , Semancik S. 
Published: March 2011

ABSTRACTThe structure and morphology of clean and Pd-doped epitaxial SnO2 films were studied with the atomic force microscope (AFM). The SnO2 films were grown by reactive sputter deposition on three different substrates yielding epitaxial orientations: (101) SnO2 / r-cut sapphire, (100) SnO2 / basal sapphire, and (110) SnO2 / TiO2 (110). AFM imaging of monolayer amounts of Pd deposited onto the epitaxial SnO2 films shows that the Pd is dispersed at 300 K and forms clusters after annealing to 500 K in vacuum.
Effect of Si Addition on the Reaction Growth and Morphology of an Aluminide Compound in Al-Cu-Si/Ti-W Bilayers
Authors: Park M. , Krause S. J. , Wilson S. R. 
Published: March 2011

ABSTRACTThe effect of the addition of Si to an Al alloy on the reaction morphology of Al12W in Al-Cu-Si/Ti-W bilayers was studied with plan-view and cross-section transmission electron microscopy (TEM). The addition of 0.5 wt.% Si to an Al-0.5Cu alloy film increases multiple spiked growths of the Al12W compound by the reaction of the Al-0.5Cu-0.5Si film with the Ti-W sublayer after heat treatment at 450°C for 30 min. Increasing the Cu and Si content from 0.5 to 1.5% significantly reduced the spiked growth of Al12W into the Al-1.5Cu-1.5Si film. However the spike number density remained high compared to the reaction of a binary Al-1.5Cu film with the Ti-W layers. The result indicates that the addition of Si to form a ternary Al-Cu-Si film results in a more irregular, less planar Al12W morphology. This morphology can have a detrimental effect on thermal stability and electromigration resistance.
Effects of Substrate Pretreatments on Growth of Polycrystalline Diamond Thin Films on Si(100) Substrates
Authors: Lai C. , Wachtman J. B. , Sigel G. H. , Lu P. , Cosandey F. C. , Rudd G. , Oliver J. L. , Garofalini S. H. 
Published: March 2011

ABSTRACTMicrostructures of polycrystalline diamond thin films deposited on silicon (100) substrates which were pretreated by (a) wet polishing, (b) dry polishing, (c) sonication and (d) acid etching, respectively, have been studied by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HREM). The thin films were deposited by using a Hot Filament Assisted Chemical Vapor Deposition (HFCVD) technique, with a methane to hydrogen ratio of 0.5%. Atomic Force Microscopy (AFM) was used to characterize substrate surfaces after the different pretreatments. The wet and dry polishing produced substrates with scratch type of defects while the sonication and acid etching caused pit type of defects. Planar and cross-sectional SEM studies indicated that diamond films on the wet and dry polished surfaces were continuous and had a high density of nucleation sites while the films on the sonicated and acid etched surfaces were discontinuous in nature under the same deposition time (8 hours) and condition. Cross-sectional HREM studies did not reveal any intermediate layers such as SiC and amorphous carbon between the thin films and substrates. Tungsten carbide nano-sized crystals, however, were observed to be dispersed at the interface region. These particles were believed to be formed during carburizing a fresh tungsten filament and deposited on the substrate during initial stage of growth.
Morphology of Diamond Films Produced by ECR-PACVD
Authors: Jin S. , Moustakas T. D. 
Published: March 2011

ABSTRACTDiamond films were produced at a relatively low pressures (<1 Torr) by the ECR-PACVD method of gas mixtures containing CO (5%), H2 (95%) and traces of oxygen at substrate temperatures from ambient (no intentional heating) to 1050°C. Faceted surface morphologies were observed even at the lowest temperature of growth. The microstructure is dominated by octahedral crystals below 600°C, by cubic crystals at 800–900°C, and by multiply twined (111) crystals at temperatures higher than 950°C. The weak temperature dependence of the growth rate is consistent with hydrogen abstraction from the growing surface being the rate controlling step.
Surface Reconstruction and Strain Relief in Si1−x-Gex Films on Si(100)
Authors: Yu Qiuming , Clancy Paulette 
Published: March 2011

ABSTRACTThe equilibrium structure of a variety of Si1−xGex/Si heterostructures have been simulated by Molecular Dynamics, modeled by the Stillinger-Weber potential, to investigate the effect of strain on the surfaces of SiGe thin Alms. It was found that the strain in SiGe/Si(100) thin films was relaxed by the segregation of Ge to the surface. Rebonding of sub-surface atoms into dimers in the presence of a vacancy or cluster of vacancies above them was observed in the ensuing surface reconstruction. For SiGe/Si, the amount of “re-bonded missing dimers” in the top two layers increased with increasing Ge composition. But for Ge/Si(100), a V-shaped twinning defect was observed in the Ge thin film. To further investigate the effect of strain on surface reconstruction, bulk Si and Ge structures were also studied. For bulk Si, several rebonded missing dimers were found at the surface, while for bulk Ge(100), the surface showed a typical 2×1 reconstruction. All these findings corroborate recent experimental studies and theoretical predictions.
The Use of Novel Organometallic Sources in Metal Organic Chemical Vapor Deposition (MOCVD)
Authors: Biefeld R. M. 
Published: March 2011

ABSTRACTIn metal organic chemical vapor deposition (MOCVD), the most commonly used sources are the trimethyls of Al, Ga, In, and Sb, and PH3 and ASH3. New organometallic sources are being developed as the understanding of the deposition process improvesand allows for the determination of the effects of source type and growth condition on the properties of the grown films. These new sources are safer and allow for the growth of higher purity materials using more favorable growth conditions. InSb and AlSb prepared using these trimethyl-sources are not of high enough quality to be used in many current device applications. Alternate organometallic Sb sources are being investigated to improve the materials characteristics of InSb grown by MOCVD.InSb grown using trimethylindium (TMIn) and trimethylantimony (TMSb) or triethylantimony (TESb) yielded similar quality materials under similar growth conditions. InSb grown using triethylindium (TEIn) and TESb under similar growth conditions yielded very poor quality n-type material. Three new organometallic Sb sources, triisopropylantimony (TIPSb), tris(dimethylamino)antimony (TDMASb), and tertiarybutyldimethylantimony (TBDMSb) are being investigated. The growth of InSb using TIPSb, TDMASb, or TBDMSb and TMIn was investigated over a temperature range of 350 to 475 °C. InSb grown from TDMASb had similar properties to InSb grown from TMIn and TMSbwhen using a similar temperature and V/III ratio range. The growth rates of InSb using TMIn and either TIPSb or TBDMSb at temperatures <= 425 °C were proportional to both the TMIn flow rate and the temperature. The surface morphology of InSb grown using eitherTIPSb 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. The InSb with the highest mobility was grown at 400 °C and a V/III ratioof 3 using TIPSb. It was n-type with a carrier concentration of 2.5 × 1015 cm−3 and a mobility of 78,160 cm2/Vs at 77 K. Both n- and p-type InSb were grown using TBDMSb with mobilities up to 67,530 and 7773 cm2/Vs, respectively at 77 K. The mobility for InSb using either TIPSb or TBDMSb was optimized by going to lower temperatures, pressures and V/III ratios. The opposite was truefor 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 TIPSb or TBDMSb and TMIn under the conditions investigated in this work.
Crystal Surface Stoichiometry and the Fermi Level Effects on Outdiffusion of Si in GaAs
Authors: You Horng-Ming , GöSele Ulrich M. , Tan Teh Yu 
Published: March 2011

ABSTRACTGaAs samples doped with Si to a concentration of ∼2.7×10 18cm−3 were annealed at temperatures between 800 and 1000°C for 3 to 20 hours under As-rich and As-poor conditions for Si outdiffusion which were then measured using the capacitance-voltage method employing an electrochemical profiler. The deduced Si diffusivity showed strong dependencies on the As4 vapor phase pressure, PAs4 and on the electron concentration, n. When reduced to that under intrinsic conditions, activation enthalpies of 3.91 eV and 4.19 eV were obtained for As-rich and As-poor annealing cases, respectively. From these results, it is concluded that Si outdiffusion in GaAs is governed by the triply-negatively-charged Ga vacancies, .
Laser Assisted CVD of Aluminum from a Novel Liquid Alane Precursor
Authors: Han Jaesung , Senzaki Yoshihide , Gladfelter Wayne L. , Jensen Klavs F. 
Published: March 2011

ABSTRACTWe describe pyrolytic laser assisted chemical vapor deposition of Al from dimethylethylamine-alane with 514 nm radiation from an Ar+ laser. Results from deposition on different substrates, including Pt, Au, W, and Si, provide insight into to thermal and nucleation effects in the laser writing process. High purity Al lines with resistivity close to bulk Al are reported for a range of operating conditions. The relationship between operating parameters and the resulting properties of the deposited lines is investigated. We also demonstrate a two-step fast writing process based on fast laser nucleation of lines followed by selective chemical vapor deposition of Al on the nucleated pattern.
The Reduction of CuII Compounds by Excimer Laser Irradiation for Copper Metal Deposition
Authors: Suys M. , Moffat B. , Bernier M.-H. , Izquierdo R. , Poulin S. , Meunier M. , Sacher E. 
Published: March 2011

ABSTRACTThe short (UV) wavelength and the large beam cross-section of excimer lasers are expected to permit high resolution projection patterning and, for this reason, excimer laser deposition of Cu from organometallic precursors appears to be an interesting alternative for metallization in ULSI circuits. Unfortunately, the photolytic decomposition of those precursors leads to strong carbon contamination of the deposits. However, the valence state of the Cu in such deposits is unknown. In this paper, the reduction of two Cu (II) compounds, Cu(hmac)2 and Cu(hfac)2, under excimer laser irradiation in a hydrogen ambient is discussed. It is shown, with X-ray Photoelectron Spectroscopy, that, under our experimental conditions, Cu(hmac)2 is reduced to a Cu (I) compound while some of the Cu(hfac)2 appears to be reduced to the metallic state. Furthermore, reaction of the SiO2 substrate with the carbon from the Cu(hmac)2 precursor is observed.
Laser-Assisted Low Temperature Deposition of WSix from WF6 and SiH4
Authors: Izquierdo R. , Desjardins P. , Elyaagoubi N. , Meunier M. 
Published: March 2011

ABSTRACTA laser direct writing system has been developed for low temperature deposition of WSix on TiN from a gas mixture of WF6 and SiH4-. An Ar+ laser (488 nm, 1.5 W) and a diode laser (796 nm, 1.0 W) are used as photon sources. Lines are written at scan speeds of up to 100 μ/s from a flowing gas mixture of WF6 and SiH4 diluted in Ar. Lines 1.5 to 11 nm wide and 20 to 180 nmthick are obtained at a writing speed of 100 μ/s with the Ar+ laser. Lines written using the diode laser are typically 4 to 12 μm wide and 160 to 860 nm thick. W/Si ratio in the deposits, as measured by Auger electron spectroscopy (AES), isbetween 1.5 and 1.8.Surface analysis of the interaction of this gas mixture with the TiN surface without laser irradiation shows that W, Si and F are adsorbed on the surface when exposed simultaneously to WF6 and SiH4 producing an adsorbed layer where W/Si ratio is 1.3 and F/W ratio 1.7.
Chemical Vapor Deposition of Copper Alloys
Authors: Smart Christopher J. , Reynolds Scott K. , Stanis Carol L. , Patil Arvind , Kirleis J. Thor 
Published: March 2011

ABSTRACTChemical vapor deposition of metals is becoming a desirable alternative to physical deposition techniques (e.g. sputtering, evaporation) for applications in chip wiring. This is due to the possibility of achieving highly conformal coverage and low processing temperatures. Additionally, it is convenient to be able to enhance the physical properties (e.g. corrosion resistance, adhesion, electromigration resistance) of metal films used for chip interconnection by incorporation of an alloying agent. We have investigated the possibility of extending our current copper deposition process to allow for the deposition of copper alloys. By careful selection of the precursors and reactor conditions, simultaneous decomposition of the two compounds to give clean alloy films is effected. Using this co-deposition method, Cu-Co and Cu-Te alloy films were prepared. Precursor and reaction chemistry are discussed as well as some properties of the resulting films.
Organometallic CVD of CoGa and Related Bimetallic thin Films from Novel Single Source Precursors
Authors: Fischer Roland A. 
Published: March 2011

ABSTRACTA series of volatile heterodinuclear organometallic compounds of the general formula L(CO)nM-ER1R2(D) (L = CO, η5-C5H5, P(CH3)3; n = 1–4; M = Mn, Fe, Co, Ni; E = Al, Ga, In; R = H, alkyl; D = O- or N-donor ligand) was syndiesized and characterized. These compounds exist either as low melting solids or liquids with vapor pressures typically around 10–50 mTorr at room temperature. The possibility to grow bimetallic thin films ME (e.g. CoAl, CoGa, Coin, Niln etc.) from those single source molecular precursors by thermally induced low pressure OMCVD was investigated. It was shown that the thin film composition, namely the metal stoichiometry, can be controlled by the ligand set at the metal atoms.
Alternative Organometallic Precursors for CVD of Tungsten
Authors: Kirss Rein U. , Gordon Douglas , Kirlin Peter S. 
Published: March 2011

ABSTRACTTwo solid, air stable, volatile tungsten complexes, tris(methylvinylketone) tungsten, I, and tris(butadiene)tungsten, II, have been investigated as precursors for chemical vapor deposition (CVD) of tungsten containing films. Thermal gravimetic analysis, (TGA), of I and II under argon showed the onset of decomposition at 140°C and 150°C, respectively. A rapid weight decrease corresponding to loss of all three ligands, methylvinyl ketone or butadiene, was observed.Tungsten film growth under hydrogen using I was investigated on Si, SiO2, Cu, TiN, Si, and Pt substrates. Selective tungsten film growth on platinum using a hydrogen carrier was observed at temperatures above 200°C. No appreciable tungsten deposition was observed on clean Si, SiO2. Cu or TiN surfaces below 400°C. No oxygen or carbon was detected in these films to the level of EDX analysis (∼1%) for depositions at 200°C. Increased growth temperatures resulted in increasing amounts of oxygen incorporation. The films grown at 200°C were smooth whereas cracking was observed in films grown at 300°C. The volatile products from the deposition were identified by a combination of gas chromatography and mass spectrometry. Small amounts of methylvinylketone. and methylethylketone were observed. Higher molecular weight species are as yet unidentified, but constituted the majority of the products.
Single-Source Precursors to Titanium Nitride Thin Films
Authors: Winter Charles H. , Lewkebandara T. Suren , Sheridan Philip H. , Proscia James W. 
Published: March 2011

ABSTRACTThe syntheses of the first single-source precursors to gold-colored titanium nitride films are reported. The precursors have the empirical formula [TiCl2(NHR)2(NH2R)0–2] and [TiCl4(NH3)2] and are obtained upon treatment of titanium tetrachloride with alkylamines or ammonia in nonpolar organic solvents. Both precursors sublime without decomposition between 80–120 °C and 0.01–0.1 mmHg. Deposition of titanium nitride films on glass and silicon substrates was achieved using either precursor at substrate temperatures of 475–600 °C. The films were characterized by x-ray diffraction, resistivity measurements, and X-ray photoelectron spectroscopy. In particular, low levels of carbon and chlorine contaminants were observed in the films.