bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Nucleation and Template Growth of Ti Silicides
Authors: Tung R. T. 
Published: April 2011

AbstractThe direct nucleation and growth of Ti silicide on the surfaces of Si(100) and amorphous Si were studied. Silicide phase formation depended on the temperature and the stoichiometry of deposition and the crystallinity of the substrate. A very low temperature, − 500°C, for the nucleation of the low-resistivity C54-TiSi2 phase was observed on amorphous Si. Stoichiometric and uniform TiSi2 layers were grown with the depositions of pure Ti. On crystalline Si, uniform TiSi2 layers were also grown at ∼ 500°C with a co-deposited template layer. The much reduced C54 formation temperature is discussed in terms of a possible circumvention of precursor amorphous silicide phases during surface nucleation.
Substrate Influence on the Formation of Titanium Silicide on Polycrystalline Silicon
Authors: da Silva Ana Neilde Rodrigues , Furlan Rogerio , Santiagoaviles J. J. 
Published: April 2011

AbstractIn this work we investigated the influence of the polycrystalline silicon substrate on the titanium silicide formation process. The results are compared to those obtained when single crystal silicon wafers are used. We observed that the polycrystalline substrate affects both the kinetics of formation of the phase TiSi2-C49 and the temperature of transition from TiSi2-C49 to TiSi2-C54. The temperature of this phase transition is also influenced by the presence of phosphorous in the polycrystalline silicon substrate. In order to prevent degradation of the silicide film formed on polycrystalline silicon, the maximum temperature of RTP has to be lower than 900°C. Due to the high chemical reactivity between titanium and oxygen present in the ambient, we also investigated the use of a protective cap. For this purpose, a thin amorphous silicon layer was sputter-deposited sequentially on Ti films without breaking the vacuum.
Formation of Titanium Silicide Strap Lines by the Deposition of a Double Layer of Amorphous Silicon - Titanium
Authors: da Silva Ana Neilde Rodrigues , Furlan Rogerio , Santiagoaviles J. J. 
Published: April 2011

AbstractThe reaction between an amorphous silicon film, with a titanium film, yields the formation of a titanium silicide film useful in the fabrication of local interconnection lines (straps) for integrated circuits. In this work we look at the influence of the films thickness ratios on the silicide formation on silicon dioxide. For structures with 70 or 80 nm of amorphous silicon deposited on 40 nm of titanium, we found that after a low temperature treatment of 650 °C, nominally utilized in the first processing step for the formation of self-aligned silicides, the formation of the metastable TiSi2 (C 49) and Ti5Si3 phases occurs. For silicon rich structures i.e.. 90 nm of amorphous silicon on 40 nm of titanium, besides the stable TiSi2 (C54) the metastable phases mentioned above are also detected. In this case strong morphological changes, and silicon precipitates are observed.
In Situ Analysis of the Formation of thin TISI2, (>50 nm) Contacts in Submicron Cmos Structures during Rapid Thermal Annealing
Authors: Clevenger L. A. , Cabral C. , Roy R. A. , Lavoie C. , Viswanathan R. , Saenger K. L. , Jordan-Sweet J. , Morales G. , Ludwig K. L. , Stephenson G. B. 
Published: April 2011

AbstractA detailed in situ study of silicide reactions during rapid thermal annealing of patterned structures was performed to determine the effects of linewidth (0.2 to 1.1 μm), dopants (arsenic, boron or phosphorus) and silicon substrate type (poly-Si or <100>-Si) on the C49 to C54-TiSi2 transformation. A synchrotron x-ray source and a high speed position sensitive detector were used to collect x-ray diffraction patterns of the reacting phases on a millisecond time scale, in situ, during annealing. We demonstrate that most patterned C49-TiSi2 structures (0.2 to 1.1 μm in width, 2 to 4 μm2 in area) will incompletely transform into C54-TiSi2 during rapid thermal annealing. The C49 to C54 transformation ends at about 900°C and further annealing to higher temperatures does not force the remaining C49 to transform into C54. We also observed that the C54 formation temperature increases as the linewidth of the silicide structure decreases. These results are explained by a low density of C54 nuclei in C49 which leads to a one-dimensional growth of C54 grains along the length of the patterned lines. Finally the incorporation of a Mo implant into either poly-Si or <100>-Si before the deposition of titanium is shown to increase the percentage of C49 that transforms into C54 and also to lower the C54 formation temperature.
Selective Titanium Silicide for Industrial Applications
Authors: Maury D. , Regolini J. L. , Gayet P. 
Published: April 2011

AbstractThe possibilities of using TiSi2 for contacts and interconnects in 0.25 μm and below design rule ICs are at present being investigated using the standard solid phase reaction (salicide) technique. Some problems still remain, such as phase transformation or dewettability over narrow lines. Over the last few years we have developed a TiSi2 selective CVD technique which is being used for 200 mm wafers in an industrial integrated cluster reactor. The system consists of two reaction chambers: one for Si epitaxy (and related alloys) and the other for TiSi2 deposition. The process sequence involves three main steps: (i) a wet chemical wafer cleaning, (ii) a selective silicon epitaxy for elevated source/drains to obtain minimum substrate consumption and (iii) the deposition of TiSi2 using the H2/SiH4 (or DCS)/TiCl4 gas system in the 650–750°C temperature range. The whole process time per wafer is shorter than 4 min. Selectivity, stoichiometric composition and resistivity of around 16 μmΩcm are obtained. The growth rate, uniformity, grain size and doping effects have been studied on single, polycrystalline, doped and undoped silicon. Device wafers have been used to compare the two processes, standard and CVD, obtaining electrical results such as lower series resistances, and a linewidth independent sheet resistance of down to 0.20 μm.
Stability Hierarchy of New Epitaxial Phases in CoSi2
Authors: Miglio Leo , Tavazza Francesca 
Published: April 2011

AbstractIn this paper we report the cohesion energy curves for different CoSi2 structures calculated by a semiempirical tight binding scheme. We set up a stability hierarchy among them and provide a kinetic model which could explain very recent and apparently contradictory Molecular Beam Epitaxy findings concerning the stability of a new pseudomorphic phase, i.e. the defected CsCl.
Structural Properties of β-FeSi2 Bulk Crystal Grown by Horizontal Gradient Freeze Method
Authors: Kakemoto H. , Tsaic Y. , Beye A. C. , Katsumata H. , Sakuragi S. , Makita Y. , Obaraa A. , Kobayashi N. , Shibata H. , Uekusa S. , Tsukamoto T. , Tsunoda T. , Imaif Y. 
Published: April 2011

AbstractWe report on the synthesis of β-FeSi2 bulk materials using Horizontal Gradient Freeze (HGF) method. Chunk and powder FeSi2 or high-purity Fe (4N) and Si (9N) were used as starting materials. Three values (1:2, 2:5 and 1:3) of the Fe:Si ratio were selected in the very narrow α and β ranges of the equilibrium phase diagram. Samples were melted between 1300°C and 1500°C in high purity graphite crucibles covered with boron nitride. After cooling, the samples were kept at 800°C and 900°C during 66 to 100 hours, leading to transformation from α to β phase. Cooling rate and annealing time were taken as the two main parameters to optimize the growth conditions. Principal structural characterization was made by X-ray diffraction (XRD). Correlation with stoichiometry was achieved using the results of Rutherford Backscattering Spectroscopy (RBS) and Electron Probe X-Ray Micro Analysis (EPXMA). The samples obtained from 1:2 ratio exhibited mainly β phase while the 2:5 ratio specimens revealed almost α phase structure. The samples prepared with 1:3 ratio was found as a mixture of α and β phases under Si-rich conditions.
Initial Stages of Reactions between Monolayer Fe and Si(001) Surfaces
Authors: Hasegawa M. , Kobayashi N. , Hayashi N. 
Published: April 2011

AbstractReactions between 1.5 monolayer(ML) Fe deposited on Si(001)-2 × 1 and -dihydride surfaces were studied in situ by reflection high-energy electron diffraction and time-of-flight ion scattering spectrometry with the use of 25 keV H ions. The reactions between Fe and Si which were successively deposited on Si(001)-dihydride surface were also studied. After the room temperature deposition Fe reacted with Si(001)-2 × 1 substrate resulting in the formation of polycrystalline Fe5Si3. By annealing to 560∼650°C composite heteroepitaxial layer of both type A and type B β -FeSi2 was formed. On the dihydride surface polycrystalline Fe was observed after 1.5ML Fe deposition at room temperature, and reaction between Fe and Si(001)-dihydride surface is not likely at room temperature. We observed 3D rough surface when we deposited only Fe layer on the dihydride surface and annealed above 700°C. The hydrogen termination of Si(001) surface prevents the deposited Fe from diffusing into the substrate below 500°C, however the annealing above 710°C leads to the diffusion. We obtained 2D ordered surface, which showed 3 × 3 RHEED pattern as referenced to the primitive unreconstructed Si(O01) surface net, when we deposited 2.5ML Fe and 5.8ML Si successively onto Si(001)-dihydride surface and annealed to 470°C.
Role of the Surface Steps on the Growth of CrSi2 on {111} Silicon.
Authors: Rocher André M. , Oustry André , David Marie José , Caumont Michel 
Published: April 2011

AbstractCrSi2 layers grown by solid phase epitaxy on a nominal (111) Si surface exhibit in the same proportion two different orientation relationships, named A and B. When CrSi2 is deposited on a 8° vicinal (111) Si surface, B-type orientation is favoured with respect to the A type. This result can be explained by the fact that both the step width introduced by the miscut and the planar coincidence between {1100}Crsi2 and {111}Si are nearly equal to 23Å. Edge type misfit dislocations are observed at the interface with the same spacing. Their Burgers vector component along [111] is almost compensated by the atomic steps along the <110> directions. The role of the steps is discussed in term of elastic energy. Steps introduce misfit dislocations which make possible coherent growth of the B type orientation.
Microstructure and Stress in Mo Films Sputttr-Deposited on Glass Substrates
Authors: Lee Tsang-Shaw , Gu Gin-Lern , Tseng Bae-Heng 
Published: April 2011

AbstractMo films are deposited on various glass substrates using the sputtering technique. The film stress and texture are greatly affected by the substrate materials. For the films grown on borosilicate glass both DC and RF sputtering may produce films with desirable properties. However, the films with compressive stress can be deposited on sodalime glass substrates only by RF sputtering. Preferred orientations are (211) and (110) for the film grown on borosilicate glass substrate and the film grown on sodalime glass substrate, respectively.
Elastic Property Estimation in Polycrystalline Films with Crystallographic Texture and Grain Shape
Authors: Hendrix B. C. , Yu L. G. , Xu K. W. , He J. W. 
Published: April 2011

AbstractAlthough methods of measuring the elastic properties of thin films have made great advances with the use of bulge testing of membranes, deflection of micromachined beams, and nanoindentation, most results are still being compared to either isotropic or single crystal elastic constants, neither of which are, in general, appropriate for textured polycrystalline films. This paper uses recent results of a self-consistent model (after Krbner and Kneer) which calculates the elastic anisotropy arising from crystallographic texture and which has been extended to predict the anisotropy resulting from grain shape. These results are compared to the various Voigt, Reuss, and Hill approximations that are appropriate for different crystallographic textures. The accuracies of the different models are evaluated in terms of their ability to predict the biaxial modulus and indentation compliance that are most commonly measured in thin films.
Investigation of Aluminum Thin Films Using Electron Backscatter Diffraction and the New Technique of Orientation Imaging Microscopy
Authors: Dingley D. J. , Field D. P. 
Published: April 2011

AbstractAluminum thin films deposited onto silicon substrates coated with silicon dioxide or a layered structure of titanium and titanium nitride have been investigated using the combined techniques of electron backscatter diffraction and orientation imaging microscopy. By these methods the local texture and spatial distribution of texture components was established. It was observed that whereas the material exhibited an overall <111> texture with the in-plane direction <110> uniformly distributed, there were variations in the local texture and distribution of orientations with clustering of grains of similar orientation. Individual grains within the clusters were nearly perfect and varied in orientation by only a few degrees. The effective grain size differed greatly on whether the cluster size of similarly oriented grains or the diameter of individual grains within the cluster was considered to constitute the grain structure. No strong bias was found in favor of coincident site oriented grain pairs though in some cases the frequency of occurrence of low angle boundaries was less than is expected on a purely random basis. Additional experiments were carried out in order to establish the suitability of orientation imaging microscopy for microstructure characterization of interconnect lines in integrated semiconductor device technology.
Rodrigues-Frank Space Representations of Fiber Texture
Authors: Rajan Krishna , Petkie Ronald 
Published: April 2011

AbstractThe concept of fcc fiber texture is examined in the context of Rodrigues-Frank (R-F) representations. Using fiber texture in thin films as the basis of our analysis, it is shown that this approach when combined with grain specific determination of crystallographic orientation provides a useful means of detecting a number of texture components with relatively small grain sampling densities. The application of R-F representations is also shown to be a useful methodology to couple grain boundary structure information with microtexture data.
Characterizing Surfaces and Overlying Multilayer Structures Using Grazing Incidence X-Ray Reflectivity
Authors: Pedulla Joseph , Deslates Richard D. , Joensen Karsten D. , Gorenstein Paul 
Published: April 2011

AbstractA proposed hard x-ray (>10 keV) telescope design uses multilayers on gold coated replica substrates. We investigated the grazing incidence x-ray reflectivity (0.154 nm) of super polished fused silica, gold coated fused silica, and mutilayers deposited on each. Gold coatings of 100 nm were deposited by both magnetron sputtering and ion beam sputtering. Carbon/nickel multilayers (20 layer pair with 4.0 nm d-spacing) were deposited by ion beam sputtering. We report the results of specular and diffuse reflectivity characterizations of these samples. The easured x-ray reflectivities are compared to model calculations evaluating film thickness, ensity, optical properties, and interface roughness/diffusion. It is concluded that substrate and film quality (roughness and density) can be determined by grazing incidence reflectivity measurements and correlated to final multilayer reflectivity and model calculations.
Synthesis and Properties of Crystalline Carbon Nitride Composite Superhard Coatings
Authors: Chung Yip-Wah 
Published: April 2011

AbstractMultilayer carbon nitride/TiN coatings were synthesized using a dual-cathode dc magnetron sputtering system. Fully crystalline films can be obtained when the thickness of the carbon nitride component is on the order of one nm. There appears to be a strong correlation between the occurrence of strong TiN(111) texture and the hardness of these multilayer coatings, as controlled by target powers, nitrogen partial pressure and substrate bias. These coatings can be synthesized at near room temperatures, with smooth surface morphology and hardness in the range of 45–55 GPa.
Surface Morphology and Microstructure of Al-O Alloys Grown by ECR Plasma Deposition
Authors: Marshall D. A. , Barbour J. C. , Follstaedt D. M. , Howard A. J. , Lad R. J. 
Published: April 2011

AbstractThe growth of polycrystalline and amorphous aluminum-oxygen alloy films using electronbeam evaporation of Al in the presence of an O2 electron-cyclotron-resonance (ECR) plasma was investigated for film compositions varying from 40% Al (A12O3) to near 100% Al (A1Ox). Processing parameters such as deposition temperature and ion energy were varied to study their effects on surface texture and film microstructure. The Al-rich films (AlOx) contain polycrystalline fcc Al grains with finely dispersed second-phase particles of γ-A12O3 (1–2 nm in size). The surface roughness of these films was measured by atomic force microscopy and found to increase with sample bias and deposition temperature. Stoichiometric A12O3 films grown at 100°C and 400°C without an applied bias were amorphous, while an applied bias of -140 V formed a nanocrystalline γ-A12O3 film at 400°C. The surface roughness of the A12O3 increased with temperature while ion irradiation produced a smoother surface
On Superstoichiometric Ti-C, Si-C and Ta-C PVD Coatings
Authors: Knotek O. , Lugscheider E. , Löffler F. , Barimani C. 
Published: April 2011

AbstractDifferent PVD coatings are used to reduce the wear of tools and other machine parts, and to improve their service life [1]. During the last years, a number of developments have been made in the field of carbon coatings. These coatings show a low friction coefficient, e.g. against steel, and therefore have a high potential in decreasing the friction and wear of coatings in tribological applications. This PVD process can be stabilised by using a metallic target which is vaporised in a carbon and hydrogen atmosphere. The carbon rich side of the metal/carbon system is object of this study.
Slightly superstoichiometric coatings in the range of 50–60% carbon content have very good friction properties too and with the potential to better film properties (coating adhesion due to internal stress, microhardness). In this paper the mechanical properties of coatings in the systems Ti-C, Si-C and Ta-C are described and the different microstructures are discussed.
Microstructural Characterization of a Zirconia-Titania-Yttria Thermal Barrier Coating
Authors: Diaz P. , Ralph B. , Edirisinghe M. J. 
Published: April 2011

AbstractThe phase transformations in a plasma sprayed zirconia-titania-yttria thermal barrier coating (TBC), subjected to different thermal treatments, in the temperature range 900–1400°C, were characterized by X-ray diffraction (XRD). Different transformation trends dependent on the cooling rate of the specimens from the treatment temperature, were observed. The study of the fracture surfaces of the as-sprayed and thermally treated ceramic coatings, using scanning electron microscopy (SEM), allows elucidation of the changes in the microstructure and the fracture mechanisms. The as-sprayed and thermally treated (1400°C) ceramic microstructures were also studied using transmission electron microscopy (TEM).
Rapid Thermal Chemical Vapor Deposition of Polycrystalline Silicon-Germanium Films on SiO2 and Their Properties
Authors: Li V. Z-Q , Mirabedini M. R. , Kuehn R. T. , Gladden D. , Batchelor D. , Christenson K. , Wortman J. J. , Ozturk M. C. , Maher D. M. 
Published: April 2011

AbstractIn this work, polycrystalline SiGe has been viewed as an alternative gate material to polysilicon in single wafer processing for the deep submicrometer VLSI applications. We studied deposition of the silicon-germanium (SiGe) films with different germanium concentrations (up to 85%) on SiO2 in a rapid thermal chemical vapor deposition reactor using GeH4 and SiH4/H2 gas mixture with the temperature ranging from 550°C to 625°C. Since the SiGe RTCVD process is selective toward oxide and does not form nucleation sites on the oxide easily, an in-situ polysilicon flash technique is used to provide the necessary nucleation sites for the deposition of SiGe films with high germanium content. It was observed that with the in-situ polysilicon flash as a pre-nucleation seed, the SiGe deposited on SiO2 forms a continuous polycrystalline layer. Polycrystalline SiGe films of about 2000Å in thickness have a columnar grain structure with a grain size of approximately 1000Å. Compositional analyses from Auger Electron Spectroscopy (AES) and Rutherford backscattering (RBS) show that the high germanium incorporation in the SiGe films has a weak dependence on the deposition temperature. It is also noted that the germanium content across the film thickness is fairly constant which is a critical factor for the application of SiGe films as the gate material. Lastly, we found that the surface morphology of SiGe films become smoother at lower deposition temperature.
Crystalline Grains and Electrical Properties of Vacuumevaporated SnO2Thin Films
Authors: Man W. K. , Yan H. , Wong S. P. , Wong T. K. S. , Wilson I. H. 
Published: April 2011

AbstractWe have studied grain growth and electrical properties of polycrystalline tin oxide (SnO2) thin films prepared by vacuum-evaporation with a two-step process: evaporation of tin metal films and then oxidation of these metal films. Surface morphology of the SnO2thin films was observed by atomic force microscopy. The grain size of the SnO2thin films is found to increase with the film thickness and oxidation temperature. Kinetics of the grain growth is discussed in terms of a 3-dimensional diffusion limited process. The diode current-voltage (I-V) characteristic of the SnO2/Si heterojunctions (isotype and anisotype) was measured in the temperature range of 14K-383K. Changes in the diode ideality factor and threshold voltage with temperature are discussed. In addition, we present ambient tunnelling I-V results measured from individual SnO2grains.
Reactive Phase Formation in Thin Films: Evolution of Grain Structure
Authors: Barmak K. , Michaelsent C. , Rickman J. , Dahmstt M. 
Published: April 2011

AbstractIt is a well known fact that the properties and performance of polycrystalline materials, including polycrystalline thin films, are strongly affected by the grain structure. Therefore, in treating reactive phase formation in these films, it is (or it will inevitably be) necessary to quantify the grain structure of reactant and product phases and its evolution during the course of the reaction. Theoretical models and the conventional view of thin film reactions, however, have been largely extensions, to small and finite dimensions, of theories and descriptions developed for bulk diffusion couples. These models and descriptions primarily focus on the growth stage and to a much lesser extent on the nucleation stage. Consequently, these models and descriptions are not able to treat the development of product phase grain structure. Recent calorimetric investigations of several thin film systems demonstrate the importance of nucleation kinetics (and hence nucleation barriers) in product phase formation and provide quantitative measures of the thermodynamics and kinetics of formation of the product phases, thereby allowing some degree of comparison with reaction models. Furthermore, microstructural investigations of thin-film reactions demonstrate the non-planarity of the growth front and highlight the role of reactant-phase grain boundaries. In this paper, a summary of these experimental studies and recent theoretical treatments, which combine nucleation and growth in an integrated manner, is presented, with particular emphasis on the Nb/Al system. These experiments and models lead to a new view of reactive phase formation and grain structure evolution as one in which the latter is an integral part of the former. Based on this view, directions for future research are discussed.