bluuebunny/crossref_metadata_2025 huggingface dataset:
Defect Penetration During the Plasma Etching of Semiconductors
Authors: Rahman M. , Foad M. A. , Hicks S. , Holland M. C. , Wilkinson C. D. W.
Published: March 2011

Dry etching can introduce defects into the material being etched. Simple expressions for both sidewall and top surface defect distributions may be obtained by assuming that the defects are introduced according to a phenomenological source function. Calculations of conductance based on these expressions are found to describe very well measurements on dry-etched wires and epilayers. Mechanisms by which defects can penetrate into the sample are discussed. The role of sample heating and defect diffusion is examined. In-situ measurements of sample temperature during a dry-etch run indicate that simple diffusion is insufficient to account entirely for the observed damage. Instead, dry-etch damage may arise from other mechanisms such as by knock-on replacement collisions, or via a channeling effect. A more complex form of diffusion may also affect the final damage distribution.
Ultrapure Iron Film Formation by Mass-Separated Ion Beam Deposition Method
Authors: Miyake Kiyoshi , Ohashi Kenya , Komuro Matahiro
Published: March 2011

Isotopically enriched iron (56Fe or 57Fe) films were deposited on Si(100) substrates at RT by a low-energy (50–500 eV), mass-separated ion beam deposition (IBD) method. All the IBD-Fe films had smooth and fine-grained polycrystalline bcc-structure, and showed superior electrochemical corrosion resistance against both NaCl and H2SO4 solutions compared with die highest-purity (RRRIH=6000) iron metals ever reported. A distinct energy dependence of the degree of corrosion resistance and different microcrystalline structures observed by TEM cross-sections for the 50 eV- and 100 eV-IBD-Fe films indicate that their film growth modes are completely different.
Epitaxial Growth of MgO Single Crystal Thin Film in Oxygen Atmosphere
Authors: Yang M. H. , Flynn C. P.
Published: March 2011

We have studied the epitaxial growth of MgO single crystal thin films by depositing Mg onto MgO substrates in an oxygen atmosphere. This method provides a simple way to dope Mg18O layers uniformly into Mg16O. The well controlled layer thicknesses are suitable for bulk diffusion studies both in the MgO epilayer and the MgO substrate. The MgO growth rate was measured and found to be proportional to the Mg flux and to the square root of oxygen pressure at a given temperature, obeying the law of mass action. High quality MgO single crystal thin films, as indicated by RHEED and x-ray diffraction, were found to grow over u wide temperature range, as in the earlier work1 using e-beam evaporation.
Formation of Well-Separated Buried and Surface Nickel-Silicide Layers in a Single Ion Implantation Step
Authors: Wu M. F. , De Wachter J. , Hendrickx P. , Pattyn H. , Van Bavel A. M. , Langouche G. , Vanhellemont J. , Bender H. , Maenhoudt M. , Bruynseraede Y.
Published: March 2011

An unusual Ni distribution with two completely separated buried and surface suicide layers has been observed after Ni ion implantation in Si(111) kept at a temperature of 300° C, with a dose of 1.1 × 1017/cm2 and at a fixed energy of 90 keV. RBS/channeling, AES and cross-sectional TEM have been used to study this phenomenon as a function of the substrate temperature and Co co4mplantation. A model is presented, based on the diffusion of the transition metal, the defect annealing during the implantation, and the gettering power of the surface and the end of range defects.
Substrate and Particle Dependent Deep Level Generation in Silicon by MeV Particle Beams
Authors: Trauwaert M.-A. , Vanhellemont J. , Simoen E. , Claeys C. , Johlander B. , Harboe-Sörensen R. , Adams L. , Clauws P.
Published: March 2011

The results are presented of a fundamental study of electrically active damage introduced in silicon diodes by irradiation with the fission products resulting from the decay of a 252Cf source and with high energy protons. The influence of the oxygen content of the silicon substrate and the irradiation type on the damage formation is investigated using deep level transient spectroscopy. A radiation hardening effect by interstitial oxygen is observed. Bom types of irradiation create the same dominant defect levels but with different relative densities. The identification of the induced deep levels are confirmed by isochronal annealing results.
Electron-Beam-Induced Damage in GaAs/AlGaAs Heterostructures
Authors: Tanaka N. , Kawanishi H. , Ishikawa T.
Published: March 2011

We have investigated the effects of electron beam (EB) irradiation on the optical and electrical properties of GaAs/AlGaAs heterostructures in the energy range between 5 and 25 keV. By using 10 keV-EB irradiation, the photoluminescence from quantum wells is shown to be degraded at doses higher than 1×1019 electrons/cm2, further, the two-dimensional-electron-gas mobility is degraded at doses more than 5xl020 electrons/cm2. EB irradiation of 5 and 25 keV, on the other hand, produces no degradation of both properties even at these dose levels. Such an energy dependence of EB-induced damage can be interpreted in terms of the EB energy dependence of the electron penetration and energy-loss-rate. Electrons with an incident energy of 5 keV do not penetrate sufficiently deep into the active region, and 25 keV electrons have an energy-loss-rate that is too low to cause damage.
Metastable Phases Obtained by Laser Glazing in Fe-B And Fe-C Based Alloys
Authors: Antonione Carlo , Battezzati Livio , Riontino Giuseppe , Turco Cosima
Published: March 2011

Amorphous phases are observed in laser glazed Fe82 Bl2C6, Fe 82 C18 alloys by Transmission Electron Microscopy. Differential Scanning Calorimetry is used to monitor the amorphous to crystalline transformation. Metastable crystalline structures are also found, such as e-phase in Fe82 C18 and Fe 70Mo10 C20 alloys and, respectively, very fine bainite and retained austenite.
Dynamic Processing Characteristics for Melt Spinning
Authors: Adler R.P.I. , Hsu S.C.
Published: March 2011

Although during melt spinning the ongoing interactive thermal and mass transfer processes are affected by both materials properties and process variables, a simplified resolution for this complex system can be obtained by first identifying and characterizing those substrate and melt material combinations that provide useful, steady state production performance. A previously described standardized falling droplet/inclined plane test procedure that simulates the dynamic wetting and solidification behavior during melt spinning is being used to generate a range of phenomenological information for combination of melt (droplet) and substrate (plane). Real differences in dynamic wetting/solidification patterns are being correlated with melt spinning performance. Phenomenological and process characteristics from some melt spinning experiments for representative material combinations have been analyzed to verify the validity of these projected correlations as well as to provide complementary information about the interrelation of melt puddle/substrate dynamics with product dimensions and quality.
A Kinetic and Thermal Study of the Superalloy Melt Spinning Process
Authors: Huang S. C. , Laforce R. P.
Published: March 2011

The correlation between ribbon thickness and the length of the melt puddle residing on the surface of a melt-spinning wheel was established for a Ni-base superalloy. Since the melt puddle length defines the solidification time in which a ribbon with a certain thickness is formed, the above correlation allowed a direct derivation of the propagation velocity of the solid-liquid interface. The solidification rate V (mm/s) so obttined as a function of ribbon thickness S (mm) is V = 3.54S−1. Further, the above solidification correlation was analyzed using heat transfer considerations to yield information about the ribbon-wheel interfacial thermal conductance, the solid-liquid interfacial temperature, and the local cooling rate through the ribbon thickness. These thermal results are compared to those deduced from the secondary dendrite arm spacing measurements. Finally, there is a discussion on the ribbon microstructure based on our rapid solidification kinetic result.
Structure and Consolidation Properties of Some Melt Extracted Steels
Authors: Wood J.V. , Gagg C.
Published: March 2011

A range of Fe-Mn and Fe-Ni steels have been processed by melt extraction to give fibres and particulate. The consolidation and sintering performance of these alloys are presented. Densities of up to 95% can be achieved with hardnesses in the range 400–500 Hv while possessing grain sizes less than 20μm. Salient features of the sintered structures are described and it is concluded that sintering of pre-annealed short fibres compares favourably with a more conventional approach using powders.
Hot Isostatic Consolidation of P/M Superalloys
Authors: Kissinger R.D. , Nair S.V. , Tien J.K.
Published: March 2011

The kinetics of powder consolidation, or densification, and the powder morphological changes ocurring during hot isostatic pressing (HIP) are studied as a function of particle size distribution and hold time at HIP temperature for the nickel base superalloy RENE-95. In order to understand the extent of individual powder particle deformation during consolidation and its effect on subsequent prior particle boundaries (PPB), particle size distribution was studied as a variable. Particle size distributions studied include monosized (75–90 um), bimodal ( 75–90 um and 33–35 um) and commercial (<104 um) size distributions. The experimental results of HIP densification kinetics are compared with a newly developed analytical deformation mechanism model for HIP consolidaiton which takes into account the effect of a distribution of particle sizes on the kinetics of densification.
Dispersion Strengthening of Metallic Glasses
Authors: Donovan P.E.
Published: March 2011

It is proposed that the effects of crystalline inclusions on the mechanical properties of metallic glasses are due to the presence of compressive stress-fields arising from the difference in thermal expansion coefficients of the crystals and the glass. Because of the dilatational micro-mechanism of plastic flow in metallic glasses these compressive stresses raise the tensile fracture stress but reduce the hardness. The temperature dependence of the hardness changes in partially crystallised Fe40Ni40P14B6 is consistent with this model.
The Effect of Phosphorous on the Corrosion Resistance of Glassy Copper Zirconium Alloys
Authors: Burleigh T.D. , Latanision R.M.
Published: March 2011

Phosphorous has been shown to have a beneficial effect on reducing the corrosion rate of various metal alloys. This research was undertaken to determine by what mechanism the phosphorous is able to improve the corrosion resistance of metals. The amorphous copper-zirconium system was chosen for experimentation because the amorphous structure eliminates the complications due to crystalline defects. The zirconium forms zirconia (ZrO2), which is normally a protective surface oxide. Copper-zirconium alloys with and without phosphorous were melt-spun, and were tested in various electrolytes. In comparing Cu-42Zr-2P with Cu-4OZr, the results show that the corrosion rate of Cu-42Zr-2P is lower in 1N sulfuric acid, and significantly lower in 3.5 w/o NaCl, and in 1N HCl. ESCA analysis shows that phosphorous is present in the zirconia film, and has a valence of +5. Photocurrent experiments suggest that phosphorous alters the semiconductor properties of the zirconia film.
Relaxation and Mechanical Properties Of Fe40Ni40B20
Authors: Hunger G. , Fritsch H. U. , Bergmann H. W.
Published: March 2011

Changes in physical and mechanical properties were correlated with relaxation phenomena. A quantitative description of the process is possible. Due to the anisotropy, relaxation in a particular direction does not give the same results as volume properties.
Laser Anneal and the Amorphous-Crystalline Transition in the Cu60-Zr40 Alloy System
Authors: Otooni Monde A.
Published: March 2011

Recently, significant advances have been made in establishing a theoretical basis for explaining the many structural-sensitive physical properties of amorphous materials. Viewed from both the theoretical and experimental realms, reversible annealing dependency and the structural relaxation mechanism of the amorphous solids are conceptually deducible from the concept of localized structural fluctuations. In the case of annealing, however, the limiting temperature below which no permanent atomiclevel rearrangements occur is not known and may well be dependent on several intrinsic properties of the amorphous state. In an effort to establish this limiting temperature, amorphous Cu60-Zr 40 samples have been annealed using a 1kv pulsed laser. Samples annealed during 1200, 800, 600 400, and 200 μ sec. have been analyzed by using Differential Scanning Calorimetry (DSC), High Resolution Electron Microscopy (HREM), and microanalysis. Analysis of the DSC indicates variations in both height and the shape of the exotherms from the samples annealed above 600 μ sec. duration. The results from HREM of these samples indicate the onset of amorphous-crystalline transition evidenced during 200 μ sec. annealing.
Induced Nucleation and Growth Mechanisms in Rapidly Solidified Alloys
Authors: Otooni Monde A.
Published: March 2011

An attempt has been made to influence the trend of crystallization of a solidifying melt through the crystallization of an amorphous substrate undergoing transformation in its contact at the solid liquid interface. Two cases have been studied. In one case involving amorphous Cu60-Zr 40/Sn interface, it has been found that both textural and microstructural characteristics of the substrate, at the onset of the amorphous-crystalline transition, exert profound influence in crystallization, of the solidifying melt. High resolution electron microscopy and diffraction reveal that the preferred textural orienzation of the solidified tin is (111) at the interface and (100) far from the interface. In addition, an abundant array of edge dislocations found at the interface points to the role that these defects have played in the nucleation process of the solidifying melt. In the case of Ni60 Nb40/A1 the textural characteristics of the solidifying aluminum melt appear to be less perturbed by the crystallization effects of the substrate.
Structure and Recalescence Behavior of Underctoled Nickel-Tin Alloys
Authors: WU Yanzhong , Piccone Thomas J. , Shiohara Yuh , Flemings Merton C.
Published: March 2011

Small nickel-tin alloy samples (3.2 g) were bulk undercooled in a Pyrex-brand borosilicate glass medium using a levitation melter. Recalescence was directly observed utilizinq a rapid thermal measurement system (resnonse time less than 10 us) consisting of two silicon photodiodes, signal amplification system, and a digital storarie device.

Results of this research include: (1) measured undercoolings ranqed up to about 250 K; (2) both total solidification time and recalescence time become shorter with increasing initial undercooling; (3) in the case of hypoeutectic (Ni-25wt%Sn) alloy, a range of recalescence times was observed from 500 ms for a low undercooling (about 35 K) to 2 ms for a hiqh undercooling (about 230 K); (4) thermal profiles upon solidification of hypoeutectic comnosition alloys showed the existence of two distinct nucleation events; (5) although cooling rates before nucleation were generally low (<50 K/s), structures of fineness expected in rapid solidification processing were typically observed; (6) fineness of microstructure increases with increasing undercooling; and (7) uniform distribution of second phase was achieved by increasing undercoolina.
Oxide Dispersions in Rapidly Solidified Ti Alloys
Authors: Konitzer D.G. , Kirchheim R. , Fraser H.L.
Published: March 2011

Techniques of rapid solidification processing were used to refine a dispersion of rare earth oxides in Ti. The dispersion was produced by laser surface melting and subsequent heat treatment of a Ti-Er alloy. The second phase was identified as the rare earth oxide. The stability of the dispersion was investigated analytically and experimentally and the correlation between the analysis and experiments was shown to be very good.
Laser Melting and Surface Alloying
Authors: Mordike B. L. , Bergmann H. W.
Published: March 2011

The metallurgical aspects of laser melted and laser alloyed surfaces are discussed. It is shown how varying the laser parameters can influence the microstructure and properties.
Influence of Laserglaze on The Microstructure and Wear Resistance Of A Cast Nickel-Base Superalloy
Authors: Yunlong Ge , Zhuangqi Hu , Wei Gao , Changhsu Shih
Published: March 2011

Influence of laserglaze on the microstructure and wear resistance of a cast nickel-base superalloy has been studied, which contains very high contents of refractory metals (Mo 33 wt%, W 17 wt%). After surface treatment by laserglaze the alloy structure changes extraordinarily. This change of microstructure enhances the alloy properties. Hardness of the laser melted region is evidently increased, and wear resistance and and corrosion resistance are also improved.
Rem and Rheed Studies of Pb Adsorption on Si(111)
Authors: Tanishiro Yasumasa , Fukuyamaand Masahiko , Yagi Katsumichi
Published: March 2011

Structure changes of Si(111)-Pb surfaces due to deposition and heat treatment are studied by REM-RHEED. Surface structures observed are summarized as a phase diagram. Formation of an incommensurate layer(α) and a phase transition between incommensurate structures of α and α' is described.
Surface Diffusion: Atomistics and Surface Morphology (Summary of MRS Symposium B Panel Discussion)
Authors: Grabow M. H. , Feibelman P. J. , Gilmer G. H. , Cooper B. H. , Mo Y. W.
Published: March 2011

This paper gives some of the highlights of a panel discussion on surface diffusion held Monday, November 30, 1992 at the Fall MRS Meeting in Boston, Massachusetts. Four invited speakers discussed computer modeling techniques and scanning tunneling microscopy experiments that have been used to provide new understanding of the atomistic processes that occur at surfaces. We present a summary of each of the invited talks, indicate other presentations on surface diffusion in this proceedings, and provide a transcript of the two discussion sessions.
Scaling Description of Sub-Monolayer Epitaxial Growth
Authors: Zangwill A.
Published: March 2011

Recent experimental results aimed at the measurement of surface diffusion constants by use of scanning tunnelling microscopy and diffraction techniques have reawakened interest in the statistical properties of two-dimensional island nucleation and growth in the submonolayer regime. Classical homogeneous rate equation studies published over twenty years ago established a simple relationship among the number density of stable islands, the deposition flux, and the adatom surface diffusion constant. Recent Monte Carlo simulation studies confirm this prediction and considerably extend the scope of such a scaling description of submonolayer epitaxial growth. In this article, I review the current status of theory and experiment in this area and suggest some areas for future research.
Uhv-Mocvd Growth and in Situ Characterization of Epitaxial TiO2 Films
Authors: Chen Samuel , Gysling H. J. , Paz-Pujalt G. R. , Blanton T. N. , Castro T. , Chen K. M. , Fictorie C. , Gladfelter W. L. , Franciosi A. , Cohen P. I. , Evans J. F.
Published: March 2011

Thin films of TiO2 were grown on SrTiO3 and Al2O3 using Ti(OC3H7)4 in the absence of any external oxygen source such as H2O or O2. On SrTiO3 (001), epitaxial anatase (001) formed even at temperatures (800 °C) above the anatase to rutile phase transition temperature. In situ reflection high energy electron diffraction (RHEED) was used to monitor structural evolution during growth, and the films were further characterized by Auger electron spectroscopy (AES), transmission electron microscopy (TEM), and x-ray diffraction. Reaction kinetics were monitored using mass spectrometry, and these results, combined with temperature-programmed reaction spectroscopy, gave some insight into the deposition process.
How CVD SI/GE Layer Growth is Controlled by Each one of the Reaction gas Components
Authors: Kühne H. , Kissinger G. , Zaumseil P. , Hinrich S. , Richter H.
Published: March 2011

Applying the previously derived “Three-Partial-Rates” model, CVD-Si/Ge-thin film growth and composition is described as influenced by the partial pressures of silane, germane, and hydrogen chloride. The effect of hydrogen carrier gas throughput variation is considered, as well as the density reduction of polycrystalline growth defects by the action of hydrogen chloride and hydrogen.
Photodissociation of Trimethylindium and Trimethylgallium on GaAs(100) at 193nm Studied by Angle-Resolved XPS
Authors: Shogen Satoshi , Ohashi Masafumi , Hashimoto Satoshi , Kawasaki Masahiro , Hosokawa Yasuo
Published: March 2011

The chemisorption and photodecomposition of trimethylindium (TMIn) and trimethylgallium (TMGa) on GaAs(100) surfaces have been studied by angle-resolved X-ray photoelectron spectroscopy. The In-C bond cleavage of the adsorbed TMIn was observed when the substrate temperature was raised from 150 K to 300 K. The dissociation generates methyl radicals that react with the substrate Ga species to form the Ga-C bond. The In-C bond is also dissociated by 193 nm laser irradiation of TMIn adsorbed on the GaAs at 150 K. Irradiation at 351 nm caused no change in the X-ray photoelectron spectra since photodissociation is not due to the photoabsorption of the GaAs substrate but the photodecomposition of the adsorbed species. Similar results are observed for TMGa on a GaAs(100) substrate.
Submicron Scale Interface Roughness in Quantum Wells Observed by High-Resolution Cathodoluminescence Microscopy
Authors: Murashita Tom , Wada Kazumi , Kanisawa Kiyoshi , Inoue Naohisa
Published: March 2011

A single quantum well (SQW) is grown at a high substrate temperature and low growth rate (HTLR growth) in order to reduce interface roughness. The lateral well thickness variation in the SQW is characterized by the cathodolumincscence microscopy. It is clarified that HTLR growth can be applied to make a smooth interface for advanced devices.
Characterization of the ZnSe/GaAs Interface Layer by Tem and Spectroscopic Ellipsometry
Authors: Dahmani R. , Salamanca-Riba L. , Beesabathina D. P. , Nguyen N. V. , Chandler-Horowitz D. , Jonker B. T.
Published: March 2011

The interface between ZnSe thin films and GaAs substrates is characterized by High Resolution Transmission Electron Microscopy and room temperature Spectroscopic Ellipsometry. The films were grown on (001) GaAs by Molecular Beam Epitaxy. A three-phase model is used in the reduction of the ellipsometric data, from which the presence of a transition layer of Ga2Se3, with a thickness of less than 1 nm, is confirmed. These results corroborate the high resolution transmission electron microscopy images obtained from the same samples.
Microscopic Morphology of Gallium Clusters on GaAs(001)
Authors: Lowes T. D. , Zinke-Allmang M.
Published: March 2011

A microscopic study of the system Ga/GaAs(001) is presented to explain the origin for different Ga cluster shapes on a single surface. The model is based on the finding that a significant fraction of the Ga clusters reaches below the GaAs surface plane and the shape of these depressions represents a minimum energy configuration if low-index planes are formed. Other metal/compound semiconductor systems may display similar shape modifications.
Phase Transition Mechanism for the Morphology of Surface Microstructures
Authors: Kleban P. H.
Published: March 2011

We present general results demonstrating the existence of thermodynamic driving forces that effect the shape of small equilibrium regions (“droplets”), such as islands in epitaxial growth. These effects are due to critical fluctuations. They occur when the droplet, if it were infinite, would be at or near a second-order phase transition. Depending on the droplet geometry, they can lead to elongation, sharpening of “points”, or healing of “dents”. It is important to consider such effects, since in many surface preparation and modification techniques the shape of small islands can have a significant influence on the ultimate surface morphology.
Equilibrium Crystal Shape of Silicon Near (001)
Authors: Tersoff J. , Pehlke E.
Published: March 2011

We have calculated the equilibrium shape of a silicon crystal at orientations near (001), both at T=0 and at elevated temperature [1], using methods developed previously to study stepped surfaces [2,3,4]. Comparison with recent experiments shows that several topographic features observed on Si direcdy reflect the equilibrium shape. In particular, our results resolve an apparent discrepancy between theory and experiment, regarding facetting between regions of single-layer and double-layer steps. In addition, the calculated crystal shape suggests an explanation for observed low-angle facetting on very flat (001) surfaces.
Surface Waves and Strain Modulations in Si1-xGex Alloy Layers on Si
Authors: Cullis A. G. , Robbins D. J. , Pidduck A. J. , Smith P. W.
Published: March 2011

The growth of strained, continuous Si1-xGex epitaxial alloy layers on Si can, under certain conditions, result in the occurrence of marked, small-scale layer thickness fluctuations in the form of crystallographically-aligned, interlocking ripple arrays. In the present work, combined transmission electron microscope (TEM) and atomic force microscope studies are employed to reveal the detailed nature of these surface ripples. TEM contrast studies demonstrate that well-defined, oscillatory strain variations accompany these ripple structures, the presence of which is shown to be associated with partial elastic strain-relief and lowering of the energy of die strained-layer system.
Microstructural Evolution and Coherent Islands
Authors: Drucker Jeff
Published: March 2011

Microstructural evolution in systems containing strained islands (coherent, incoherent or both) is investigated. The growth rate of an individual island coarsening in an ensemble of strained islands is obtained by including elastic effects on surface diffusion of adatoms to and the equilibrium solubility of strained islands. For strained islands growing on a quasi-rigid substrate, coherent islands grow more slowly than incoherent islands of the same radius. Consequently, the island growth rate accelerates at the coherent to incoherent transition. The model agrees with recent experimental observations in Ge/Si(100) heteroepitaxy.
Computer Simulation Study of Film Formation Process
Authors: Sasajima Yasushi , Taya Syubo , Ozawa Satoru , Yamamoto Ryoichi
Published: March 2011

The initial stage of film formation process was studied by 2 dimensional (2D) Monte-Carlo (MC) simulation and 3D molecular dynamics (MD) simulation. The atomistic interaction was simple pair-wise Lcnnard-Joncs potential for the 2D MC study and embedded atom potential (EAM potential) for the 3D MD simulation. The 2D MC study has revealed the dependence of film growth mode on the potential parameters that correspond to atomic size and binding energy. More realistic MD simulation has been performed using EAM potential for the three kinds of systems, Ni/Cu(111), Ag/Cu(111) and Au/Ni(111). The relaxed atomic structures of such systems showed the difference of atomic combination; coherent interface was obtained for Ni/Cu(111) system, incoherent interface with specific rotational relationships for Ag/Cu(111) andAu/Ni(111).
Strained Field of Silver Overlayers Deposited on the Reconstructed Si(111) Surface
Authors: Martinez-Miranda L. J. , Santiago-Aviles J. J. , Perez-Sandoz Raul , Carolissen Randolph , Weitering H. H. , Graham W. R.
Published: March 2011

We have performed high resolution x-ray diffraction measurements of the strain field in UHV deposited Ag(111) films on a 7×7 reconstructed Si(111) surfaces shows a faulted epitaxial layer with a 0.4% out-of-plane strain, and a -1% in-plane strain. The strain field anisotropy is similar to that observed on epitaxial YSi2-x on Si(111), and is an unexpected result for the present system, due to the lack of a lattice match between the silver and silicon unit cells. The out-of-plane diffraction peaks have an angular distribution of 1.23°, full width at half maximum (FWHM), as determined from rocking curve measurements.
Strain Relaxation in Epitaxial Heterostructures: Sensitivity of High Resolution X-Ray Diffraction
Authors: Goorsky M. S. , Horng S. T. , Sriffler S. R. , Stanis C. S.
Published: March 2011

Comparison of high resolution x-ray diffraction and transmission electron microscopy measurements of Si-based heterostructures demonstrates that diffraction is much more sensitive to strain relaxation than previously reported. This study used as-grown and annealed Si1-x Gex structures grown on (001) Si by UHV/CVD. (004), (113), and (115) rocking curves were employed. Using the TEM measurements as a quantitative guide, relaxation was observed in rocking curves when the misfit dislocation line density was as low as 1 μ-1. Also, interference fringes strongly depend on the presence of interfacial defects. At higher dislocation densities, the diffraction peak from the epitaxial layer broadens considerably but does not shift to a position that represents complete relaxation. Broadening of the substrate diffraction peak also occurs, which is due to dislocations that loop into the substrate.
Single-Crystal AU-NI Solid Solutions Grown by MBE
Authors: Marty A. , Gilles B. , Patrat G. , Joud J. C. , Chamberod A.
Published: March 2011

Epitaxial solid solutions Au1-x Nix (100) have been obtained at room temperature on Au(100) substrates by the MBE technique. The layers are 10 nm-thick and the composition x has been varied up to 0.37. A large strain (2–3%) has been measured by X-ray diffraction. The lattice parameters have been measured in two perpendicular directions, perpendicular and parallel to the surface. In the latest case, the grazing-incidence technique has been used. Because this technique is very sensitive to the surface, the strain results may be re-interpreted if, the upperlOO nm are enriched in Au.
Molecular Dynamics Modeling of Growth, Micro-Structure and Stresses in Sputter-Deposited Films with Impurity Atom Incorporation
Authors: Fang C. C. , Jones F. , Prasad V.
Published: March 2011

The structure and intrinsic stresses of sputter-deposited thin films are studied via a two-dimensional molecular dynamics (MD) model. Two body potentials are used to represent the interaction between film atoms, substrate atoms, ions and argon molecules. First, a nearly perfect substrate having zero stress is constructed using constant temperature and constant pressure algorithms. Then the film is deposited with and without in-situ argon ion bombardment and with and without an argon background gas; a source of impurities. The adatom energy is varied in order to investigate its influence on the film structure. During the simulation the film is allowed to expand and contract depending on the intrinsic stresses. The models demonstrate, for the first time, that the transition from large tensile to large compressive stresses in sputter deposited thin films is caused by the incorporation of tightly packed argon impurity atoms, achieved only at sufficiently high levels of argon ion bombardment and nickel adatom energies.
The High Temperature Stability and Relaxation of UHV/CVD SiGe Thin Films
Authors: Stiffler S. R. , Stanis C. L. , Goorsky M. S. , Chan K. K.
Published: March 2011

ABSTRACT:: High temperature (950°C) annealing is used to stimulate relaxation in UHV/CVD SiGe thin films. It is found that the films are stable to thicknesses which exceed the stability criterion of Matthews and Blakeslee [1] by a small amount. In unstable films, the misfit dislocation density increases with annealing time, reaching a maximum value. For films which exceed the empirical stability criterion by a relatively small amount, the misfit dislocations relax the film to a strain given by the film thickness and the empirical stability criterion. However, large remnant strains are observed when the relaxation process introduces relatively high dislocation densities (≳5 misfits/micron). Associated with large remnant strains are a marked propensity for dislocation banding and looping deep into the substrate with extended annealing. These results are discussed with respect to the magnitude of the misfit dislocation nucleation barrier and the energy associated with interactions among misfit dislocations.
Anisotropic Electrical Transport and Surface Microstructure in GalnP2
Authors: Friedman D. J. , Kurtz S. R. , Kibbler A. E. , Bertness K. A. , Kramer C. , Matson R. , Arent D. J. , Olson J. M.
Published: March 2011

We show that GaInP2 exhibits a directional anisotropy of the electrical conductivity when grown under the appropriate growth conditions. We relate this anisotropy to the characteristic surface microstructure of the material.
Study of Hall Effect and Magnetoresistance on a Novel Epitaxial FeSi Phase on Si(lll)
Authors: Onda N. , Sirringhaus H. , Steiner P. , Von H.
Published: March 2011

The first magneto—transport data taken on thin pseudomorphic FeSi films with the CsCl structure are presented. FeSi appears to be a Kondo system with a Kondo temperature of TK ∼ 15 K. On air-exposed films which have not been protected by a Si-cap an ultrathin magnetic oxide is formed leading to large anomalies in the Hall effect and the magnetoresistance as the film thickness approaches 20 Å.
Microstructural Characterization of High-Pressure Oxidized Si1-x Gex /Si Heterolayers
Authors: David Theodore N. , Tam Gordon
Published: March 2011

SiGe alloys have recently been of interest for fabrication of heterojunction bipolar transistors using pre-existing or modified silicon-processing technology. These devices are faster than devices using pure silicon. Because of the interest in developing SiGe device structures, various elements of processing relevant to fabrication of the devices are being investigated. One such element has been the use of thermal oxidation for isolation of SiGe devices. Utilization of the technique requires an understanding of oxidation behavior of SiGe layers under a variety of oxidation conditions. Past studies in the literature have investigated the oxidation of SiGe at atmospheric pressure or at very high pressures (∼650–1300 atmospheres). The present study investigates the wet-oxidation of SiGe structures at intermediate pressures (∼25 atmospheres) and temperatures (∼750°C). Unlike atmospheric oxidation, most of the Ge (from SiGe) remains in the oxidized silicon (SiO2) in the form of GeO2. Occasional segregation of Ge to the oxidizing interface is noted. The microstructural behavior of partially and entirely oxidized structures is presented.
The Regularities of Selective Oxidation of Copper-Aluminium Solid Solutions.
Authors: Akimov A. G. , Melnikova N. A.
Published: March 2011

The regularities of selective oxidation of copper solid solutions with 2–12 at.% aluminium have been studied by TEM, XPS and AES in combination with argon ion sputtering. It has been obtained that the increase of the aluminium concentrations in the solid solutions leads to the change of the oxidation mechanism. The internal oxidation of aluminium in Cu+(2–4at.%)Al results in the formation of the microincluslons of Al2O3 In the alloy. It has been demonstrated that the selective oxidation of aluminium in Cu+(12 at.%)Al results in the formation of uniform thin (<10 nm) aluminium oxide at the alloy surface. The kinetics of this alloy oxidation obeys the parabolic law.
Investigation of Titanium Silicon and Germanium Reaction
Authors: Aldrich D. B. , Sayers D. E. , Nemanich R. J.
Published: March 2011

It has been shown that, across the full range of Si-Ge alloy compositions, C54 Ti(Siy Ge1-y)2 will form from the reaction of Ti with Six Gei1-x (0 ≥ x ≥ 1.00). X-ray Absorption Fine Structure (XAFS) and X-Ray Diffraction (XRD) have been used to define consistent labeling of the C54 lattice parameters. In C54 Ti(Siy Ge1-y )2 the Si and Ge atoms occupy sites equivalent to the Si sites in C54 TiSi2. The Si and Ge atoms form shells about the Ti atoms that, within error, have Si and Ge occupancies consistent with the net Si and Ge atomic percents as determine by Auger microprobe depth profiled compositional analysis. There is an increase in the Si/Ge ratio (i.e., y>x) in the Titanium Germanosilicide. This increase may be due, in part, to the relative diffusion rates of Si, Ge, and Ti. The morphologies of the reacted films can be divided into three groups based on their similarity to the morphologies of C54 TiSi2 and C54 TiGe2 formed from similar solid phase reactions. The morphological groupings indicate that the morphology of the final C54 phase (and probably the reaction path) is strongly related to the Si/Ge content of the film.
Potential Step Probes of Epitaxial Growth in Electrodeposited BCC Tl2O3 Films onto FCC Conducting Metal Oxides
Authors: Phillips Richard J. , Golden Teresa D. , Switzer Jay A.
Published: March 2011

Potential step transients were investigated as an in-situ probe of epitaxial growth for electrodeposited conducting metal oxides of the Tl2O3 and PbaTlbOc systems. Changes in the induction time and growth type were observed for Tl2O3 deposition as a function of the substrate. The substrates studied were glassy carbon and [210]-textured Pb0.8Tl0.2O1.9· T12O3 deposited onto the glassy carbon electrode showed a distinct induction time, the magnitude of which was potential dependent. Also the type of growth was characterized as three dimensional with instantaneous nucleation. X-ray diffraction of this film shows a nearly random pattern. The potential step transient for Tl2O3 deposited onto the [210]-textured Pb0.8Tl0.2O1.9, showed the absence of an induction time and elimination of the growth segment. The type of growth was characterized as two dimensional. X-ray diffraction indicated epitaxy was obtained for the Tl2O3 films which grew two dimensionally onto the [210]-textured mixed oxide.
Uniformity and Surface Properties of Diamond Films made by Tilted Oxyacetylene Combustion Flames
Authors: Zhu W. , Tan B. H. , Yin Z. , Ahn J. , Tan H. S.
Published: March 2011

High quality, transparent diamond films with relatively large deposition areas have been obtained from oxyacetylene combustion flames at the atmospheric pressure using nozzle tilted at an angle φ) with respect to the Mo substrates. These films are studied using scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Experimental results show that the surface morphology and microstructure depend strongly on the processing parameters such as the gas mixture ratio of acetylene to oxygen, substrate temperature, and the nozzle angle φ. The uniformity of diamond films have been improved using this tilted combustion flame technique and some problems related with this approach are discussed.
Surface Behavior and Lattice Relaxation of SiGe/Si Strained Epitaxial Heterostructures
Authors: Chang Kevin H. , Ming Liaw H.
Published: March 2011

The correlation between the surface morphology and the lattice relaxation in strained SiGe/Si heteroepitaxy has been studied. It is found that the surface crosshateched pattern develops as the strained epilayer thickness increases. The effect of thermal annealing and boron dopant level has also been studied. The result suggests that the crosshatched morphology on the surface is constituted by surface slip steps of glissile dislocation motion in the strained epitaxial growth processing.
Interface Structure and Defects in CVD 3C-SiC on (111) and (112) TiC Substrates
Authors: Chien Fen-Ren , Nutt S. R. , Buchan N. , Carulli J. M. , Beetz C. P. , Yoo W. S. , Cummings D.
Published: March 2011

3C-SiC, lattice-matched with TiC, is a candidate for use in wide-bandgap semiconductor devices. Epitaxial 3C-SiC films were grown on (111) and (112) TiC substrates, and defects were characterized by analytical TEM.
Mechanisms and Energetics of Surface Atomic Processes, an Atom-Probe Field ion Microscope Study
Authors: Tsong Tien T.
Published: March 2011

Atom-probe field ion microscopy is capable of imaging solid surfaces with atomic resolution, and at the same time chemically analyzing atoms selected by the observer from the atomic image. The samples are restricted to those having a tip shape, but in many cases this is no longer a drawback since structures in high-tech materials are reducing in size to that comparable to or smaller than the field ion emitter tip. This technique is finding many applications in different areas. Our recent applications of this technique to the study of the dynamical behavior of surfaces and surface atoms and their mechanisms and energetics, and the atomic scale chemical and composition analysis will be briefly described.
Atomic Arrangement of Al Near the Phase Boundaries Between √3×√3-A1 and 7×7 Structures on Si(111) Surfaces
Authors: Takaoka Katsuya , Yoshimura Masamichi , Yao Takafumi , Sato Tomoshige , Sueyoshi Takashi , Iwatsuki Masashi
Published: March 2011

Scanning tunneling microscopy (STM) is used to study the structure of Al-√3×√3 domains on the Si(lll)-7×7 surface and the atomic arrangement near the domain boundary. Al-√3×√3 domains grow from the lower side of the <112> step and extend over the Si-7×7 terrace. The phase transition is observed to occur in units of the 7×7 size. Detailed investigation at around the boundary reveals that faulted halves of the 7×7 unit are adjacent to the boundary on the Si-7×7 side, while on the Al-√3×√3 side, Al adatoms occupy the T4 sites except for the rows adjacent to the phase boundaries where Al atoms occupy the Si adatom sites. The latter Al atoms play an important role to retain the dimer structure at the boundary.
Photoluminescence Intensity Enhancement of GaAs by Vapor-Deposited GaS: a Rational Approach to Surface Passivation
Authors: Jenkins Phillip P. , Hepp Aloysius F. , Power Michael B. , Macinnes Andrew R. , Barrontt Andrew R.
Published: March 2011

A two order-of-magnitude enhancement of photoluminescence intensity relative to untreated GaAs has been observed for GaAs surfaces coated with chemical vapor-deposited GaS. The increase in photoluminescence intensity can be viewed as an effective reduction in surface recombination velocity and/or band bending. The gallium cluster [(t-Bu)GaS]4 was used as a single-source precursor for the deposition of GaS thin films. The cubane core of the structurally-characterized precursor is retained in the deposited film producing a cubic phase. Furthermore, a near-epitaxial growth is observed for the GaS passivating layer. Films were characterized by transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron and Rutherford backscattering spectroscopies.
Iodine-Based dry Etching Chemistries for InP and Related Compounds
Authors: Pearton S. J. , Chakrabarti U. K. , Katz A. , Abernathy C. R. , Hobson W. S. , Ren F. , Fullowan T. R.
Published: March 2011

A comparison is given of the dry etching characteristics of InP and related materials in high ion density (>1011 cm−2 ) microwave discharges of HI, CH3I, C2H5I, C3H7I and C2H3I. The InIx species are more volatile than their InClx counterparts near room temperature and rapid etch rates can therefore be achieved without the need for sample heating. HI discharges provide faster etch rates than the halocarbon-based mixtures, but are more corrosive. All of these gas chemistries offer faster rates than conventional CH4/H2 mixtures. Halocarbon-iodide discharges still suffer from polymer deposition on the mask and within the reactor, as with CH4/H2. AES analysis shows an absence of contaminating residues with all of the iodine-based chemistries, and highly anisotropic features are obtained since the etching is driven by ion-enhanced desorption of the reaction products.
Characterisation of Wet Chemical Etching of Algaas Layers Using Dynamic Optical Reflectivity
Authors: Armstrong J. V. , Farrell T. , Turner G.
Published: March 2011

Wet chemical etching of AlGaAs layers using a dilute mixture of ammonium hydroxide and hydrogen peroxide is monitored in real-time using dynamic optical reflectivity (DOR). The AlGaAs layers were grown as a multilayer reflector stack by chemical beam epitaxy (CBE). The reflectivity of a normal incidence 3 mW, 670 nm semiconductor diode laser is monitored during the etching process and analysis of the DOR trace gives the etch rate for the different etchant concentrations used.
Laser-Induced Selective Copper Deposition on Polyimides and Semiconductors
Authors: Hwang Seong-Don , Kher S. S. , Spencer J. T. , Dowben P. A.
Published: March 2011

It has been demonstrated that copper can be selectively deposited on a variety of substrates including Teflon (polytetrafluroethylene or PTFE), Kapton (polyimide resin), silicon and gallium arsnide from solution by photo-assisted initiated deposition. A copper containing solution was prepared from a mixture of copper(I) chloride (Cu2Ci2) and decaborane (B10H14) in diethyl ether and/or THF (tetrahydrofuran). The copper films were fabricated by ultraviolet photolytic decomposition of copper chloride and polyhedral borane clusters. This liquid phase deposition has a gas-phase cluster analog that also results in copper deposition via pyrolysis. The approach of depositing metal thin films selectively by pholysis from solution is a novel and an underutilized approach to selective area deposition.
Surface Interaction Between Wf6 and GaAs Under UV Laser Illumination
Authors: Tabbal M. , Izquierdo R. , Meunier M. , Yelon A.
Published: March 2011

We have studied laser-CVD of W on GaAs by X-ray Photoelectron Spectroscopy (XPS). Deposition of W is obtained by irradiating GaAs samples with a KrF excimer laser at normal incidence to the substrate, in a cell containing WF6 mixed with H2 and Ar. We have previously shown that WF6 and GaAs react at room temperature even without laser illumination. GaF3 formation and a loss of As were detected at the surface of the samples by XPS. At laser fluences of 50mJ/cm2, this reaction appears to be enhanced by laser heating of the substrate, but no metallic W is formed. At laser fluences of 67 mJ/cm2, metallic W begins to be deposited, through a pyrolytic dissociation reaction with the substrate.
Another Step in Developing a Single Wafer Integrated Process: Rapid Thermal Low Pressure Metalorganic Chemical Vapor Deposition of Local Diffused W(Zn) Contacts
Authors: Katz A. , Feingold A. , El-Roy A. , Moriya N. , Pearton S. J. , Rusby A. , Kovalchick J. , Abernathy C. R. , Geva M. , Lane E.
Published: March 2011

A selective deposition of W(Zn) metallization, for formation of diffused ohmic contacts onto InP-based material was realized by means of rapid thermal, low pressure metalorganic chemical vapor deposition (RT-LPMOCVD). The W(Zn) layers were deposited using a reactive gas mixture that contained diethylzinc (DEZn), WF6, H2 and Ar, at temperatures of 450 to 550°C and pressures in the range of 1–5 torr. Uniform andcontinuous layers of W(Zn), 30 to 120 nm thick, were obtained. These layers contained Zn at concentrations higher than 1×l018 cm−3, which was subsequentially in-diffused into the underlying semiconductor layer to form highly doped semiconductor layers as thick as 0.2μm. As a result, the specific contact resistance of the W(Zn)/ In0.53Ga0.47 As contact was reduced to minimum value of 5×l0−6 Ω·cm2. The W(Zn) film were found to be mechanically stable with a small compressive stress of 5.10−8 dyne. cm−2, and dry etch rates of up to 90 nmmin.