bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Situ Laser Ablation Plasma Diagnostics in the Film Growth Regime - Effects of Ambient Background Gases
Authors: Geohegan D. B. 
Published: March 2011

AbstractThe propagation of the laser-induced plasma formed by KrF irradiation of Y1Ba2Cu3O7 has been characterized in background pressures of oxygen and argon typically used for thin film growth. The ion current transmitted through the background gases was recorded along the normal to the irradiated pellet as a function of distance in order to measure the decreasing velocity and magnitude of the expanding plasma current due to collisional slowing and attenuation of the laser plume. The integrated ion charge delivered to a substrate at low pressures can be described by elastic scattering giving a general integral cross sections of σc[O2] = 3.2 × 10−16 cm2 and σc[Ar] = 2.7 × 10−16 cm2. At higher pressures, inelastic-scattering leads to increased recombination and reactive conversion of ions indicated by increased fluorescence of all the species, which becomes dominated by fluorescence of YO and BaO. Spatially resolved fluorescence measurements indicate that the luminous boundary to the plasma follows a weak shock front which coincides with the ion flux propagation. The ion transmission is found to drop exponentially with distance and background pressure, in agreement with a simple scattering model which yields general scattering cross sections for ion-argon σi-Ar = 2.1 × 10−16 cm2 and ion-oxygen σi-O2 = 2.3 × 10−16 cm2 interactions in background pressures up to 300 mTorr. The general features of the plume deceleration are described in terms of a drag force model.
Real Time Optical Diagnostics in Laser Etching and Deposition
Authors: Herman Irving P. , Tang Hua , Leong Patrick P. 
Published: March 2011

AbstractOptical probing of laser-assisted chemical reactions on surfaces in real time can help explain and control these processes. Raman microprobe spectroscopy and micro laser induced fluorescence are the two optical probes employed here to investigate several examples of localized laser surface reactions. Raman microprobe analysis is used to monitor in real time the CuCl and CuCl2 products on the surface during local laser etching of copper films by Cl2 and the concomitant loss of the Cu2O passivation layer. It is also used to follow the production of Cu2O during the laser oxidation of Cu. Polarization Raman analysis is utilized to identify and analyze partially molten silicon during laser heating in vacuum and during the etching of silicon by chlorine. Laser induced fluorescence is used as a real time microprobe of desorbed products during local laser-assisted etching of Si and Al surfaces.
Selective Suppression of Carrier-Driven Photochemical Etching: Raman Spectroscopy as a Diagnostic Tool
Authors: Ashby C. I. H. , Myers D. R. , Vawter G. A. , Biefeld R. M. , Klem J. F. 
Published: March 2011

AbstractCarrier-driven photochemical etching of semiconductors can be selectively suppressed by altering the near-surface region to enhance carrier recombination, thereby reducing the supply of carriers that drive the surface etching reaction. Two methods for enhancing recombination and decreasing the etch rate at a given phonon flux include ion implantation and localized Zn diffusion. Raman spectroscopy can be employed to determine whether sufficient alteration of electronic properties has occurred to suppress etching.Carrier-driven photochemical reactions, which require direct participation of free carriers for the chemical reaction to proceed, can be selectively suppressed by increasing the minority carrier recombination rate, thereby reducing the supply of carriers that drive the surface etching reaction. Two methods for enhancing recombination and decreasing the etching quantum yield, which is the number of atoms removed per incident photon, include ion implantation and localized Zn diffusion. For ion implantation, recombination-promoting defect concentrations depend on ion species, fluence, and annealing both during and after the implantation process. Other recombination processes related to carrier scattering from ionized impurities from in-diffusion of dopants or following implant activation can control etching.Raman spectroscopy can be employed to detect changes in electronic properties that correlate with etching suppression. Changes that occur in the LO-phonon lineshape, such as those associated with phonon confinement and ionized impurity scattering, can be diagnostic of the carrier-driven etching behavior following a specific treatment. We have demonstrated two applications of Raman spectroscopy as a diagnostic for suppression of the carrier-driven photochemical etching of GaAs.
Tem, Raman, and Langmuir Probe Studies of the Heteroepitaxial Growth of Metastable Cd(x)pb (1–X) Te Alloys Deposited on BaF2 by Low-Energy Bias Sputtering
Authors: Das Suhit R. , Cook John G. , Lockwood David J. 
Published: March 2011

AbstractMetastable Cd(x)Pb(1–x)Te films with x values from 0 to 0.47, well past the range of bulk thermodynamic solubility, have been grown on single crystal (lll) BaF2 by co-deposition from CdTe and PbTe r.f. magnetron sputter targets. Cross-sectional transmission electron microscopy and transmission electron diffraction revealed epitaxial growth across the interface. However, the lattice of the deposited epilayers was observed to be typically rotated 180°C about the surface normal <111> axis of the substrate. Raman spectra of the alloys showed no evidence of segregation. Langmuir probe diagnostics were employed to estimate the energy of the ions incident on the substrate during growth which promote extended miscibility in the alloy epilayers.
Simulation of Microstructural Evolution in Polycrystalline Films
Authors: Frost H. J. 
Published: March 2011

ABSTRACTThis paper will review the topic of computer simulation of the evolution of grain structure in polycrystalline thin films, with particular attention to the modelling of the grain growth process. If the grain size is small compared to the film thickness, then the grain structure is three-dimensional. As the grains grow to become larger than the film thickness, so that most grains traverse the entire thickness of the film, the microstructure may approach the conditions for a two-dimensional grain structure. Both two- and three-dimensional grain growth have been simulated by various authors.When the grains become large enough for the microstructure to be two-dimensional, the surface energy associated with the two free surfaces of the film becomes comparable to the surface energy of the grain boundaries. In this condition, the free surface may profoundly effect the grain growth. One effect is that grooves may develop along the lines where the grain boundaries meet the free surfaces. This grooving may pin the boundaries against further migration and lead to grain-growth stagnation. Another possible effect is that differences in the free surface energy for grains with different crystallographic orientation may provide a driving force for the migration of the boundaries which is additional to that provided by grain boundary capillarity. Grains with favorable orientations will grow at the expense of grains with unfavorable orientations. The coupling of grain-growth stagnation with an additional driving force can produce abnormal or secondary grain growth in which a few grains grow very large by consuming the normal grains.
Effects of Surface Energy on the Microstructures of Thin Sb Films
Authors: Chou L. H. , Kuo M. C. 
Published: March 2011

ABSTRACTThin Sb films have been prepared on glass substrates by rapid thermal evaporation. Films with thicknesses varied from 260 Å to 1300Å were used for the study. X-ray diffraction data showed that for films deposited at room substrate temperature, an almost random grain orientation was observed for films of 1300 Å thick and a tendency for preferred grain orientation was observed as films got thinner. For films of 260 Å thick, only two x-ray diffraction peaks--(003) and (006) were observed. After thermal annealing, secondary grains grew to show preferred orientation in all the films. This phenomenon was explained by surface-energy-driven secondary grain growth. This paper reports the effects of annealing time and film thickness on the secondary grain growth and the evolution of thin Sb film microstmctures. Transmission electron microscopy (TEM) and x-ray diffraction were used to characterize the films.
Grain Growth in Titanium Silicide Films During the Formation Reaction
Authors: Corcoran Yunji L. , King Alexander H. , deLanerolle Nimal , Kim Bonggi , Berg John 
Published: March 2011

ABSTRACTTitanium films of 0.5 µm thickness were sputter deposited on silicon substrates. After rapid thermal annealing at temperatures ranging from 600°C to 850°C for times up to 45 seconds in nitrogen, transmission electron microscope (TEM) cross section specimens were made from the wafers. Grain sizes of the resulting titanium disilicide were measured from TEM cross section micrographs. The results show that C49-TiSi2 has a different grain growth rate than C54-TiSi2- Under our experimental conditions, C54-TiSi2 has a much higher growth rate. Titanium silicide on arsenic implanted silicon substrates shows a lower grain growth rate than that on unimplanted substrates under the same conditions. The thickness of the silicide layer was also measured for each specimen. The relationship of thickness and grain size will be discussed.
Grain Structure and Growth of Dispersed Phase BN-AlN Coatings Grown via Chemical Vapor Deposition
Authors: Freeman Garth B. , Lee Woo Y. , Lackey W. J. , Hanigofsky John A. , More Karren 
Published: March 2011

ABSTRACTThis paper discusses the variation in microstructures encountered during the separate depositions of boron nitride (BN) and aluminum nitride (A1N) as well as during the codeposition of BNߝA1N dispersed phase ceramic coatings. This combination was chosen in order to take advantage of the self lubricating properties of hexagonal BN along with the hard, erosion resistance of A1N. Films were characterized using scanning and transmission electron microscopy (SEM and TEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD).A range of coating microstructures are possible depending on the conditions of deposition. The best films produced, in terms of hardness, density, and tenacity, were a fine mixture of turbostratic BN and preferentially oriented A1N whiskers aligned with the whisker axis perpendicular to the substrate surface as seen by both electron microscopy and x-ray diffraction.
Texture Evolution During Grain Growth of Aluminum Films
Authors: Knorr David B. , Tracy Daniel P. , Lu Toh-Ming 
Published: March 2011

ABSTRACTAluminum films 1pm in thickness are deposited by sputtering and by partially ionized beam (PIB) deposition. In the as-deposited condition, the sputtered film has a weak texture while the PIB film has a very strong {111} fiber texture. Annealing at temperature between 250°C and 400°C for 0.5 hr induces grain growth accompanied by texture evolution. These aluminum films are characterized by an {111} texture superimposed on a random grain distribution. When the {111} component dominates as in the PIB condition, little texture evolution accompanies grain growth at successively higher temperatures. When the {111} component is weak, the random component decreases at the expense of a strengthening {111}. Grain growth kinetics are similar for both cases.
Effect of Heat Treatment on the Microstructures and Electrical Properties of Insb Thin Films
Authors: Wang P. W. , Yeh S. , Chang L. 
Published: March 2011

ABSTRACTPolycrystalline InSb thin films have been prepared by two-source thermal evaporation method. The as-deposited randomly oriented thin films develop (111) preferred orientation upon heat treatment of different maximum setting temperatures, T(max)s. Under different T(max)s, the elongate (111) grains rotate gradually the direction of the elongation respect to the thermally oxidized Si(100) substrate.The (111) preferred orientation has been seen from both cross-sectional TEM and X-ray diffraction patterns. The electrical mobility value of the thin film has been measured by the Van der Pauw′s method. A dramatic increase in the electrical mobility from few thousands, for the as-deposited film, to intermediate values of 15,000-30,000 cm2/v-s and the highest value of 36,000 cm2/v-s for thin films subjected to different T(max)s, can be correlated well to the corresponding microstruetures.
ECR Enhancement of Low Pressure PECVD Diamond Synthesis
Authors: Chang Jan-Jue , Mantei Thomas D. , Vuppuladhadium Rama , Jackson Howard E. 
Published: March 2011

ABSTRACTDiamond films have been synthesized by microwave Plasma Enhanced CVD (PECVD) and permanent magnet induced Electron Cyclotron Resonance (ECR) PECVD of hydrogen diluted methane. The films are characterized by SEM images and Raman spectroscopy. The diamond films grown by ECR-PECVD show clear-cut habits of cubic crystal in SEM images, while the film grown by microwave PECVD are the polycrystalline. A Raman line at 1333cm‒1 and broad band located at ∼1500 cm‒1 were obtained for the films grown by both methods. However, the film grown by microwave PECVD shows a larger broad band which is associated with an sp2-bonded graphitic phase
A Bulk Study of Homoepitaxy
Authors: Baxter C. S. , Somekh R. E. 
Published: March 2011

ABSTRACTWe present preliminary results aimed at investigating the effects of variation in temperature on the epitaxial growth of thin films of single elements and multilayers.In this paper we present results of a cross-sectional electron microscopy study of films in which good epitaxy has been established and then the deposition temperature has been significantly reduced (for example to 30°C from 120°C). The main objective was to study the nature of the low temperature limit of layer by layer epitaxy and the degree of roughening as a function of the deposition conditions with an emphasis on the kinetics of the process.
Material Characterization of Low-Temperature Silicon Epitaxial Growth on Patterned Oxidized Wafers by ULPCVD From SiH4/SiF4/H2
Authors: Yew Tri-Rung , Reif Rafael Reif 
Published: March 2011

ABSTRACTLow temperature silicon selective epitaxial growth on patterned oxidized wafers is becoming crucial to ultra large scale integration (ULSI) technologies. Low temperature processes can reduce dopant redistribution via solid state diffusion so that a sharp transition region can be obtained. This paper presents material characterization of epitaxial films grown on patterned oxidized wafers by ultralow pressure chemical vapor deposition (ULPCVD) from SiH4/SiF4/H2 (≤ 10 mTorr), in which SiF4 was used to explore its capability for selective epitaxial growth. The deposition temperature is 800°C. The effects of the SiF4 addition to SiH4/H2 are discussed. Defects in epitaxial layers resulting from a high composition of the SiF4 during deposition were characterized. Results of in–situ surface cleaning using a SiF4/H2 plasma are also presented.
Structural and Electrical Effects on (A1-Si)/n+Si Ohmic Contact of in Situ Silicon Cleaning by Ar IONS Bombardment
Authors: Santangelo A. , Lanza P. , Viscuso O. , Magro C. , Scandurra A. , Licciardello A. , Torrisi A. 
Published: March 2011

ABSTRACTIn situ etching of native Si02 by Ar+ ion bombardment before metal sputter deposition can increase the contact resistance of the metal-semiconductor contact. This is commonly attributed to surface contamination produced by various mechanisms or to etch-induced surface damage. In this paper, in order to elucidate the cause of the increase of contact resistance, we have studied (Al-Si)/n+Si contacts prepared by various treatments of the Si surface. We attribute the higher postalloy contact resistance of the sputter etched contacts to the existence of an Al doped layer which formation was induced by the preexisting disordered layer created by the Ar+ ion bombardment.
The Sputter Deposition and Characterisation of High Quality Single Crystal Mo Thin Films
Authors: Somekh R. E. , Van Vechten D. , Blamire M. G. , Tricker D. M. , Barber Z. H. , Glowacka D. , Kroeger R. , Stobbs W. M. , Lovellette M. N. , King S. E. , Evetts J. E. 
Published: March 2011

ABSTRACTWe report on the epitaxial growth of superconducting molybdenum films on sapphire substrates. These films are to be etched into arrays of isolated cylinders, each 1–5μm in diameter. When placed in a magnetic field and biased at 0.95 Tc(H), the flux movement associated with their bolometric response to the energy deposited when radiation is absorbed will provide the basis of a gamma-ray detector.The films were prepared by UHV sputter deposition at temperatures between 650° and 840°C. Besides standard XRD analysis the films were examined by TEM. An epitaxy orientation relationship with sapphire was found similar to that observed for niobium. Electrical conductivity measurements were made as a function of temperature down to Tc, the superconducting transition temperature, which ranged from below 0.35K to above 0.8K for films with a high room temperature resistance ratio (e.g. 300 in a 0.9pjn thick film). Results from a range of films will be presented and their Tc’s discussed.
Growth Mechanism of Epitaxial Oxide Films by Laser MBE
Authors: Nagata Hirotoshi , Yoshimoto Mamoru , Tsukahara Tadashi , Gonda Satoshi , Koinuma Hideomi 
Published: March 2011

ABSTRACTCrystallographic structure and valence state of CeO2 and Nd2-O3 films deposited by laser MBE on Si substrates were investigated by reflection high energy electron diffraction (RHEED) and X-ray photoelectron spectroscopy (XPS). In contrast with epitaxial growth of CeO2 (111) and Nd2O3(111) on Si (111), epitaxial films were not obtained on Si(001). Partially reduced mixed valence (4+ and 3+) Ce was indicated to exist by XPS in the cerium oxide film within 2nm from the interface with Si. Beyond this transition layer, two-dimensional growth of CeO2 film on Si(111) was verified from in situ RHEED and as well as on Si(001) from XPS measurements.
Domain Boundaries formed during Epitactical Growth of α-Al2O3
Authors: Bentley J. , Sklad P.S. 
Published: March 2011

ABSTRACTDomain boundaries have been characterized by transmission electron microscopy in single crystal [0001] α-Al2O3 epitactically regrown after being amorphized by stoichiometric ion implantation. The domains are facetted on {1120} and have dislocation-like features at facet intersections. End-of-range dislocation loops on (0001) appear to be the nucleation site for the domains. Diffraction contrast, high resolution imaging, and convergent beam electron diffraction techniques showed that two types of domains are present which involve cation stacking sequences which are out of phase with the matrix as a result of translation along and/or inversion of [0001]. The non-inverted regions can be described as anti-phase domains, whereas those with [0001] inverted also have a basal twin character.
Maskless Deposition of a Micropattern on a Wafer by Liquid Flow
Authors: Mil’shtein S. , Fournier C. 
Published: March 2011

ABSTRACTMetalization patterns of micron size were deposited chemically on GaAs wafers with no litography masks by means of controlled laminar flow of liquid NaOCl. Iron used for metalization was dissolved in NaOCl wafer solution. To interrupt the continuous deposition of metal on semiconductor surface, the acrylic polymer was also dissolved in the liquid. Iron deposition appears to follow given crystalographic direction <110> creating a set of parallel lines in <110> direction. Spacing between the lines and width of the metallic lines are controlled by the temperature of the process, speed of liquid flow and percentage of polymer present in the solution.
Asymmetric Relaxation in Epitaxial Layers of III-V Compounds
Authors: Turnbull A. G. , Green G. S. , Tanner B. K. , Halliwell M. A. G. 
Published: March 2011

ABSTRACTRelaxation in a 3μm epitaxial layer of GaAsSb on GaAs, a 1μm layer of InGaAs on InP and an InGaAs superlattice on InP has been investigated by double crystal X-ray diffractometry and double crystal X-ray synchrotron topography and found to be asymmetric. The origins of assymetric relaxation are discussed and the sensitivity of diffractometry and topography to the detection of layer relaxation compared.
Atomistic Simulation of Formation and Structure of Misfit Dislocations
Authors: Nandedkar A.S. , Murthy C.S. , Srinivasan G.R. 
Published: March 2011

ABSTRACTIn our earlier work [1] we had reported first theoretical observations of the spontaneous formation of 60° and 90° misfit dislocations in Au/Ni (15.9% mismatch) systems for the (111) and (001) interfaces respectively. Here, we present the analysis of the evolution of the dislocation configuration as it evolves from a highly strained coherent Au film. The driving force for the formation of these misfit dislocations was the reduction in the config-urational energy during the iterative relaxation of the atoms. A finely stepped energy minimization technique was developed to relax the high energy configuration. Misfit dislocations were also obtained for low misfit systems (Pd/Ni - 10% and Pd/Cu - 7.76%), but a modified approach, which is described here, was used for these systems which shows an energy barrier to the formation of dislocations in the low misfit systems.
In Situ Tem Studies of The Growth of Strained Si1-xGex By Solid Phase Epitaxy
Authors: Paine D. C. , Howard D. J. , Evans N. D. , Greve D. W. , Racanelli M. , Stoffel N.G. 
Published: March 2011

ABSTRACTIn this paper we report on the epitaxial growth of strained thin film Si1-xGex on Si by solid phase epitaxy. For these solid phase epitaxy experiments, a 180-nm-thick strained-layer of Si1-xGex with xGe=11.6 at. % was epitaxially grown on <001> Si using chemical vapor deposition. The near surface region of the substrate, including the entire Si1-xGex film, was then amorphized to a depth of 380 nm using a two step process of 100 keV, followed by 200 keV, 29Si ion implantation. The epitaxial regrowth of the alloy was studied with in situ TEM heating techniques which enabled an evaluation of the activation energy for strained solid phase epitaxial regrowth. We report that the activation energy for Si1-xGex (x=l 1.6 at. %) strained-layer regrowth is 3.2 eV while that for unstrained regrowth of pure Si is 2.68 eV and that regrowth in the alloy is slower than in pure Si over the temperature range 490 to 600°C.
Lattice Relaxation of Eras/Gaas: An X-Ray Scattering Study
Authors: Miceli P. F. , Moyers K. W. , Palmstrøm C. J. 
Published: March 2011

ABSTRACTThe results of a high resolution x-ray scattering study of [001]ErAs epitaxial layers grown on [001]GaAs is presented. ErAs is pseudomorphic on GaAs for thicknesses below 70Å and, for thicker films, lattice relaxation is oberved concomitant with an Increase of the In-plane mosaic due to the formation of misfit dislocations. Above 300Å, the out-of-plane transverse scattering from the ErAs lattice planes Is no longer specular and further relaxation Is related to the out-of-plane mosaic. The ratio of elastic constants, C12/C11, Is determined to be 0.126 and the thermal expansion was measured. Thin film Interference oscillations are observed and modeled. ErAs/GaAs Is an Ideal system for x-ray scattering studies of lattice relaxation and structure in epitaxial layers. Films as thin as 20Å have been studied.