Showing papers on "Chemical vapor deposition published in 1998"
TL;DR: Large panels of aligned carbon nanotubes can be made under conditions that are suitable for device fabrication under plasma-enhanced hot filament chemical vapor deposition.
Abstract: Free-standing aligned carbon nanotubes have previously been grown above 700°C on mesoporous silica embedded with iron nanoparticles. Here, carbon nanotubes aligned over areas up to several square centimeters were grown on nickel-coated glass below 666°C by plasma-enhanced hot filament chemical vapor deposition. Acetylene gas was used as the carbon source and ammonia gas was used as a catalyst and dilution gas. Nanotubes with controllable diameters from 20 to 400 nanometers and lengths from 0.1 to 50 micrometers were obtained. Using this method, large panels of aligned carbon nanotubes can be made under conditions that are suitable for device fabrication.
2,530 citations
TL;DR: In this article, the chemical and thermal stability of epitaxial nitride films is discussed in relation to the problems of deposition processes and the advantages for applications in high-power and high-temperature devices.
Abstract: Recent research results pertaining to InN, GaN and AlN are reviewed, focusing on the different growth techniques of Group III-nitride crystals and epitaxial films, heterostructures and devices. The chemical and thermal stability of epitaxial nitride films is discussed in relation to the problems of deposition processes and the advantages for applications in high-power and high-temperature devices. The development of growth methods like metalorganic chemical vapour deposition and plasma-induced molecular beam epitaxy has resulted in remarkable improvements in the structural, optical and electrical properties. New developments in precursor chemistry, plasma-based nitrogen sources, substrates, the growth of nucleation layers and selective growth are covered. Deposition conditions and methods used to grow alloys for optical bandgap and lattice engineering are introduced. The review is concluded with a description of recent Group III-nitride semiconductor devices such as bright blue and white light-emitting diodes, the first blue-emitting laser, high-power transistors, and a discussion of further applications in surface acoustic wave devices and sensors.
1,386 citations
TL;DR: In this paper, the synthesis of high quality single-walled carbon nanotubes SWNT by chemical vapor deposition CVD of methane at 10008C on supported Fe O catalysts was reported.
1,028 citations
TL;DR: In situ scanning tunneling microscopy revealed that the smaller square-based pyramids transform abruptly during growth to significantly larger multifaceted domes, and that few structures with intermediate size and shape remain.
Abstract: Chemical vapor deposition of germanium onto the silicon (001) surface at atmospheric pressure and 600 degrees Celsius has previously been shown to produce distinct families of smaller (up to 6 nanometers high) and larger (all approximately 15 nanometers high) nanocrystals. Under ultrahigh-vacuum conditions, physical vapor deposition at approximately the same substrate temperature and growth rate produced a similar bimodal size distribution. In situ scanning tunneling microscopy revealed that the smaller square-based pyramids transform abruptly during growth to significantly larger multifaceted domes, and that few structures with intermediate size and shape remain. Both nanocrystal shapes have size-dependent energy minima that result from the interplay between strain relaxation at the facets and stress concentration at the edges. A thermodynamic model similar to a phase transition accounts for this abrupt morphology change.
736 citations
TL;DR: In this article, a new approach for preparing graphitic carbon nanofiber and nanotube ensembles was developed, which entails chemical vapor deposition (CVD) based synthesis of carbon within the pores of an alumina template membrane with or without a Ni catalyst.
Abstract: We have developed a new approach for preparing graphitic carbon nanofiber and nanotube ensembles. This approach entails chemical vapor deposition (CVD) based synthesis of carbon within the pores of an alumina template membrane with or without a Ni catalyst. Ethylene or pyrene was used in the CVD process with reactor temperatures of 545 °C for Ni-catalyzed CVD and 900 °C for the uncatalyzed process. The resultant carbon nanostructures were uniform hollow tubes with open ends. Increasing the deposition time converted the carbon nanotubes into carbon nanofibers. Transmission electron microscopy and electron diffraction data show the as deposited graphitic carbon nanofibers synthesized with the Ni catalyst were not highly ordered. Heating the carbon-containing membrane at 500 °C for 36 h, however, converts the carbon nanofibers into highly ordered graphite. The electron diffraction data show a spotted diffraction pattern characteristic of single-crystal graphite with the graphitic planes parallel to the long ...
719 citations
TL;DR: In this article, the effect of metal oxide support on the catalytic activity of gold for CO oxidation was investigated and it was shown that the perimeter interface around gold particles in contact with the metal oxide supports appears to be essential for the genesis of high catalytic activities at low temperatures.
Abstract: In order to clarify the effect of metal oxide support on the catalytic activity of gold for CO oxidation, gold has been deposited on SiO2 with high dispersion by chemical vapor deposition (CVD) of an organo-gold complex. Comparison of Au/SiO2 with Au/Al2O3 and Au/TiO2, which were prepared by both CVD and liquid phase methods, showed that there were no appreciable differences in their catalytic activities as far as gold is deposited as nanoparticles with strong interaction. The perimeter interface around gold particles in contact with the metal oxide supports appears to be essential for the genesis of high catalytic activities at low temperatures.
471 citations
01 Jan 1998
TL;DR: In this article, the Boltzmann Equation is used to model the dynamics of a diamond CVD reaction in a 2D H2 plasma under conditions typical for diamond deposition.
Abstract: "Properties Band Structure, Alan T. Collins Diamond Morphology, Robert E. Clausing Mechanical Properties of Diamond, Diamond Films, Diamond-Like Carbon, and Like-Diamond Materials, Peter J. Gielisse Surface Properties of Diamond, Mark P. D'Evelyn Thermal Properties Heat Capacity, Conductivity, and the Thermal Coefficient of Expansion, V. I. Nepsha Thermal Measurement Techniques, John E. Graebner Optical Properties, Alexander M. Zaitsev Electrical and Electronic Properties, Alexander G. Gontar Characterization Characterization Methods, Karen McNamara Rutledge and Karen K. Gleason Mined Diamond Natural Diamond, Henry O. A. Meyer and Michael Seal Theory Theory of Diamond Chemical Vapor Deposition, David G. Goodwin and James E. Butler Modeling and Diagnostics of Plasma Reactors Introduction, A. Gicquel Basic Processes in Plasmas Under Conditions Typical for Diamond Deposition, A. Gicquel Basic Processes: Plasma/Surface Interactions, A. Gicquel The Boltzmann Equation, Matt Gordon Flow Modeling for a Plasma Assisted Diamond Deposition Reactor, K. Hassouni, C. D. Scott, and S. Farhat Electromagnetic Field Modeling of Diamond CVD Reactors, Timothy A. Grotjohn Modeling of the Diffusional Transport of an H2 Plasma Obtained Under Diamond Deposition Discharge Conditions, K. Hassouni, C. D. Scott, and S. Farhat Spatially Resolved Spectroscopic Analysis of the Plasma, A. Gicquel, M. Chenevier, and M. Lefebvre Methods of Chemical Vapor Deposition Growth Hot-Filament CVD Methods, Alberto Argoitia, Christopher S. Kovach, and John C. Angus Microwave Plasma Chemical Vapor Deposition of Diamonds, Peter K. Bachmann Diamond CVD Using Radio-Frequency Plasmas, Steven L. Girshick Synthesis of Diamond, Mark A. Cappelli Low Temperature CVD, Akimitsu Hatta and Akio Hiraki Structural Modification of Diamond Nucleation and Epitaxy, S. P. Bozeman, B. R. Stoner, and J. T. Glass Ion Implantation of Diamond and Diamond Films, R. Kalish and S. Prawer Processing, Victor G. Ralchenko and Sergei M. Pimenov Applications of Industrial Diamond Abrasive Applications of Diamond, K. Subramanian and V. R. Shanbhag Active Devices, David L. Dreifus and Bradley A. Fox Applications of Diamond in Computers, Richard C. Eden Diamond Vacuum Electronics, George R. Brandes Special Applications, Naoji Fujimori Cutting and Wear Applications, R. A. Hay and J. M. Galimberti Economics Economics and Commercialization, Adam T. Singer and John V. Busch "
396 citations
TL;DR: In this article, high-quality silicon nitride (or oxynitride) films made by a novel jet vapor deposition (JVD) technique are described, which utilizes a high-speed jet of light carrier gas to transport the depositing species onto the substrate to form the desired films.
Abstract: To extend the scaling limit of thermal SiO/sub 2/ in the ultrathin regime when the direct tunneling current becomes significant, members of this author's research team at Yale University, in collaboration with the Jet Process Corporation, embarked on a program to explore the potential of silicon nitride as an alternative gate dielectric. In this paper, high-quality silicon nitride (or oxynitride) films made by a novel jet vapor deposition (JVD) technique are described. The JVD process utilizes a high-speed jet of light carrier gas to transport the depositing species onto the substrate to form the desired films. The film composition has been determined to consist primarily of Si and N, with some amounts of O and H. Metal-nitride-Si (MNS) capacitors based on the JVD nitride films deposited directly on Si exhibit relatively low densities of interface traps, fixed charge, and bulk traps. The interface traps at the nitride/Si interface exhibit different properties from those at the SiO/sub 2//Si interface in several aspects. In contrast to the conventional CVD silicon nitride, the high-field I-V characteristics of the JVD silicon nitride fit the Fowler-Nordheim (F-N) tunneling theory over four to five orders of magnitude in current, but do not fit at all the Frenkel-Poole (F-P) transport theory. This is consistent with the much lower concentration of electronic traps in the JVD silicon nitride. Results from the carrier separation experiment indicate that electron current dominates the gate current with very little hole contribution. Both theoretical calculation and experimental data indicate that the gate leakage current in JVD silicon nitride is significantly lower than that in silicon dioxide of the same equivalent oxide thickness. The breakdown characteristics of the JVD nitride are also respectable. Compared to their MOSFET counterparts, MNS transistors exhibit reduced low-field transconductance but enhanced high-field transconductance, perhaps due to the presence of border traps. As expected, the JVD silicon nitride films exhibit very strong resistance to boron penetration and oxidation at high temperatures. These properties, coupled with its room-temperature deposition process, make JVD silicon nitride an attractive candidate to succeed thermal SiO/sub 2/ as an advanced gate dielectric in future generations of ULSI devices.
357 citations
TL;DR: In this paper, high-oriented, multi-walled carbon nanotubes were grown on polished polycrystalline and single crystal nickel substrates by plasma enhanced hot filament chemical vapor deposition at temperatures below 666"C.
Abstract: Highly-oriented, multi-walled carbon nanotubes were grown on polished polycrystalline and single crystal nickel substrates by plasma enhanced hot filament chemical vapor deposition at temperatures below 666"C. The carbon nanotubes range from 10 to 500 nm in diameter and 0.1 to 50 pm in length depending on growth conditions. Acetylene is used as the carbon source for the growth of the carbon nanotubes and ammonia is used for dilution gas and catalysis. The plasma intensity, acetylene to ammonia gas ratio and their flow rates, etc. affect the diameters and uniformity of the carbon nanotubes. In summary, we synthesized large-area highly-oriented carbon nanotubes at temperatures below 666C by plasma-enhanced hot filament chemical vapor deposition. Acetylene gas is used to provide carbon for nanotube growth and ammonia gas is used for dilution and catalysis. Plasma intensity is critical in determining the nanotube aspect ratios (diameter and length), and range of both site and height distributions within a given film.
331 citations
TL;DR: In this paper, a series of characterizations on the film quality by scanning electron microscope, X-ray photoelectron spectroscopy, Xray diffraction and Fourier transform infrared spectrometer has been made, and the performance of solar thermal conversion are also identified on the produced films.
320 citations
TL;DR: In this article, phase separation in thick InGaN films with up to 50% InN grown by metalorganic chemical vapor deposition from 690 to 780 °C was reported.
Abstract: We report on phase separation in thick InGaN films with up to 50% InN grown by metalorganic chemical vapor deposition from 690 to 780 °C. InGaN films with thicknesses of 0.5 μm were analyzed by θ–2θ x-ray diffraction, transmission electron microscopy (TEM), and selected area diffraction (SAD). Single phase InGaN was obtained for the as-grown films with <28% InN. However, for films with higher than 28% InN, the samples showed a spinodally decomposed microstructure as confirmed by TEM and extra spots in SAD patterns that corresponded to multiphase InGaN.
TL;DR: In this paper, the performance of silicon compounds (SiO2 and Si3N4) on 13 μm polyethylene terephthalate (PET) substrates, the barrier coatings being deposited in a dualfrequency (microwave/radio frequency) pilot-scale PECVD reactor for continuously moving flexible webs up to 30 cm in width.
Abstract: Transparent barrier coatings on polymers are receiving much attention in industry, for pharmaceutical, food and beverage packaging applications. Plasma-enhanced chemical vapor deposition (PECVD) is among several competing techniques which can produce thin layers of inorganic glassy barrier materials. In this article we describe the performance of silicon compounds (SiO2 and Si3N4) on 13 μm polyethylene terephthalate (PET) substrates, the barrier coatings being deposited in a dual-frequency (microwave/radio frequency) pilot-scale PECVD reactor for continuously moving flexible webs up to 30 cm in width. The volatile silicon compound used for SiO2 deposition is HMDSO (C6H18Si2O), while SiH4 serves to deposit Si3N4. Coating thicknesses, d, in the range 8 nm⩽d⩽200 nm, are measured using a variety of techniques, namely stylus profilometry, continuous wavelength optical interferometry, x-ray fluorescence, variable angle spectroscopic ellipsometry, and transmission electron microscopy, while film compositions are...
TL;DR: In this paper, the structural properties of a series of films grown under a variation of the dilution of the process gas silane in hydrogen, which induces a transition from highly crystalline to amorphous growth, were investigated.
Abstract: The growth of microcrystalline silicon prepared by plasma-enhanced chemical vapour deposition depends on the deposition conditions and yields films with variable content of crystalline grains, amorphous network, grain boundaries and voids. The changes in the structural properties of a series of films grown under a variation of the dilution of the process gas silane in hydrogen, which induces a transition from highly crystalline to amorphous growth, were investigated. The evolution of the crystalline volume fraction was quantitatively analysed by Raman spectroscopy and X-ray diffraction. The results confirm the need for proper correction of the Raman data for optical absorption and Raman cross-section. Transmission electron microscopy was used to investigate the characteristics and the variation in the microstructure. Upon increasing the silane concentration the strong columnar growth with narrow grain boundaries degrades towards the growth of small irregularly shaped grains enclosed in an amorpho...
TL;DR: The transition from microcrystalline to nanocrystalline diamond films grown from Ar/H2/CH4 microwave plasmas has been investigated in this article, showing that the surface morphology, the grain size, and the growth mechanism of the diamond films depend strongly on the ratio of Ar to H2 in the reactant gases.
Abstract: The transition from microcrystalline to nanocrystalline diamond films grown from Ar/H2/CH4 microwave plasmas has been investigated. Both the cross-section and plan-view micrographs of scanning electron microscopy reveal that the surface morphology, the grain size, and the growth mechanism of the diamond films depend strongly on the ratio of Ar to H2 in the reactant gases. Microcrystalline grain size and columnar growth have been observed from films produced from Ar/H2/CH4 microwave discharges with low concentrations of Ar in the reactant gases. By contrast, the films grown from Ar/H2/CH4 microwave plasmas with a high concentration of Ar in the reactant gases consist of phase pure nanocrystalline diamond, which has been characterized by transmission electron microscopy, selected area electron diffraction, and electron energy loss spectroscopy. X-ray diffraction and Raman spectroscopy reveal that the width of the diffraction peaks and the Raman bands of the as-grown films depends on the ratio of Ar to H2 in...
Patent•
31 Mar 1998
TL;DR: In this paper, a planar electroluminescent element is obtained by using a thin polydimethylsilane film as the luminescent layer, which is formed by a dry method such as vapor deposition, sputtering, or laser ablation.
Abstract: PROBLEM TO BE SOLVED: To obtain an org. electroluminescent element which is suitable as a polysilane-based planar ultraviolet light source stably emitting light at room temp. by using a thin polydimethylsilane film as the luminescent layer. SOLUTION: This element has at least a luminescent layer between a pair of electrodes and the luminescent layer comprisies a thin polysilane film represented by the formula: [(CH3 )2 Si]n . (wherein n is 5 to about 10,000). The luminescent layer is formed by a dry method such as vapor deposition, sputtering, or laser ablation. The thickness of the film is pref. about 500-10,000Å. The luminescent layer may contain a compd. having a hole transpot capability and a compd. having an electron transport capability each in an amt. of up to about 30wt.%.
TL;DR: A combination of atomic force microscopy and scanning capacitance microscopy was used to investigate the relationship between the surface morphology and the near-surface electrical properties of GaN films grown on c-axis sapphire substrates by metalorganic chemical vapor deposition as discussed by the authors.
Abstract: A combination of atomic force microscopy and scanning capacitance microscopy was used to investigate the relationship between the surface morphology and the near-surface electrical properties of GaN films grown on c-axis sapphire substrates by metalorganic chemical vapor deposition. Local regions surrounding the surface termination of threading dislocations displayed a reduced change in capacitance with applied voltage relative to regions that contained no dislocations. Capacitance–voltage characteristics obtained from these regions indicated the presence of negative charge in the vicinity of dislocations.
Patent•
14 Dec 1998TL;DR: In this paper, an apparatus for wafer processing, which comprises a chamber body and a heated liner which are thermally isolated from each other by isolating pins, is described.
Abstract: An apparatus for wafer processing, which comprises a chamber body and a heated liner which are thermally isolated from each other by isolating pins. During wafer processing, e.g., deposition of titanium nitride film by thermal reaction between titanium tetrachloride and ammonia, a wafer substrate is heated to a reaction temperature in the range of 600-700° C. by a heated support pedestal. The chamber liner and the interior chamber walls are maintained at a temperature between 150-250° C. to prevent deposition of undesirable by-products inside the chamber. This facilitates the chamber cleaning procedure, which can be performed using an in-situ chlorine-based process. The excellent thermal isolation between the heated liner and the chamber body allows the chamber exterior to be maintained at a safe operating temperature of 60-65° C. A heated exhaust assembly is also used in conjunction with the process chamber to remove exhaust gases and reaction by-products. External heaters are used to maintain the exhaust assembly at a temperature of about 150-200° C. to minimize undesirable deposits on the interior surfaces of the exhaust assembly.
Patent•
01 Jul 1998
TL;DR: In this paper, a method for filling shallow trenches 28 with a high density plasma chemical vapor deposition (HDPCVD) oxide layer 50 is presented. But the method is limited to a single layer and requires the use of two liners: a thermal oxide layer 36 and a conformal O 3 -TEOS layer 40.
Abstract: A method for filling shallow trenches 28 with a HDPCVD oxide 50. The invention has two liners: (a) a thermal oxide liner 36 and (b) an overlying conformal O 3 -TEOS protective liner 40. The O 3 -TEOS protective liner 40 prevents the HDPCVD oxide 50 from sputter damaging the trench sidewalls and the masking layer 24. The O 3 -TEOS layer has novel process temperature (400 to 560° C.) and low pressure (40 to 80 torr) that allows the O 3 -TEOS layer to deposit uniformly over thermal oxide liner 36. The method begins by forming pad oxide layer 20 and a barrier layer 24 over a substrate. A trench 28 is formed in the substrate 10 through the pad oxide layer 20 and the barrier layer 24. A thermal oxide liner 36 and a protective O 3 -TEOS liner layer 40 are formed over the walls of the trench 28 and over the barrier layer 24. Lastly, a high density plasma chemical vapor deposition (HDPCVD) oxide layer 50 is formed over the protective liner layer 40 filling the trench 28.
Patent•
13 Feb 1998TL;DR: In this paper, the pattern of holes is tailored to compensate for thermal and other effects, in particular by increasing the density of holes toward the periphery of the wafer in three or more zones.
Abstract: A showerhead used for dispensing gas over a wafer in chemical vapor deposition (CVD), especially for CVD of metals. The patterns of holes is tailored to compensate for thermal and other effects, in particular by increasing the density of holes toward the periphery of the wafer in three or more zones. Such a variable pattern is particularly useful for liquid precursors that are atomized in a carrier gas, in which case a second perforated plate in back of the showerhead face can be eliminated, thereby reducing the flow impedance and the required pressure of the liquid-entrained gas, which tends to deposit out at higher pressures. The reduce flow impedance is particularly useful for CVD of copper.
TL;DR: In this article, a two-stage i-layer growth process was designed such that the initial stage of the i layer (∼200 A) is deposited at much higher R than the bulk to ensure that the film remains within the amorphous side of the a→μc phase boundary, yet as close as possible to this boundary at low I-layer thicknesses.
Abstract: Hydrogenated amorphous silicon (a-Si:H) p–i–n solar cell performance has been optimized using a two-step i-layer growth process. This effort has been guided by real-time spectroscopic ellipsometry (RTSE) studies of the nucleation and growth of a-Si:H films by plasma-enhanced chemical vapor deposition at 200 °C using a variable H2-dilution gas flow ratio R=[H2]/[SiH4]. RTSE studies during film growth with R>15 reveal a transition from the amorphous to microcrystalline (a→μc) phase at a critical thickness that decreases with increasing R. From such results, the optimum two-step process was designed such that the initial stage of the i layer (∼200 A) is deposited at much higher R than the bulk to ensure that the film remains within the amorphous side of the a→μc phase boundary, yet as close as possible to this boundary at low i-layer thicknesses.
TL;DR: In this paper, polycrystalline Co3O4 films were prepared by normal pressure chemical vapour deposition, and the d.c. electrical conduction was investigated at temperatures from 170 to 400 K. The Seebeck coefficient indicated the films to be p-type semiconductors.
TL;DR: In this article, a nanocrystalline diamond thin film was synthesized in an Ar-CH4 microwave discharge, without the addition of molecular hydrogen, and X-ray diffraction, transmission electron microscopy, and electron energy loss spectroscopy characterizations showed that the films consist of a pure crystalline diamond phase with very small grain sizes ranging from 3 to 20 nm.
Abstract: Nanocrystalline diamond thin films have been synthesized in an Ar–CH4 microwave discharge, without the addition of molecular hydrogen. X-ray diffraction, transmission electron microscopy, and electron energy loss spectroscopy characterizations show that the films consist of a pure crystalline diamond phase with very small grain sizes ranging from 3 to 20 nm. Atomic force microscopy analysis demonstrates that the surfaces of the nanocrystalline diamond films remain smooth independent of the film thicknesses. Furthermore, the reactant gas pressure, which strongly affects the concentration of C2 dimer in the Ar–CH4 plasma as well as the growth rate of the films, has been found to be a key parameter for the nanocrystalline diamond thin film depositions.
Patent•
18 May 1998
TL;DR: An ultraviolet assisted chemical vapor deposition system for improving the adhesion, hardness, and thermal stability of organic polymer films deposited on semiconductor wafers is provided in this paper, which includes an ultraviolet lamp and a tube-shaped monomer distribution system positioned over the wafer allowing ultraviolet irradiation of the polyamide wafer before, during and/or after deposition.
Abstract: An ultraviolet-assisted chemical vapor deposition system for improving the adhesion, hardness, and thermal stability of organic polymer films deposited on semiconductor wafers is provided. The system includes an ultraviolet lamp and a tube-shaped monomer distribution system positioned over the wafer allowing ultraviolet irradiation of the wafer before, during and/or after deposition. Processes for depositing organic polymer films on semiconductor wafers are also provided. The processes include one or more depositions, one or more ultraviolet exposures, and one or more anneals.
TL;DR: The first reports of electrochemical studies using diamond were in the mid-1980s as discussed by the authors, and during the past several years, the field has attracted increasing attention, and the electrochemical properties of diamond have been summarized.
Abstract: Electrochemical reactions typically involve electron transfer between an electrode and a dissolved chemical species at a solid-electrode/liquid-electrolyte interface. Three broad classes of electrochemical applications may be identified: (1) synthesis (or destruction), in which an applied potential is used to bring about a desired chemical oxidation or reduction reaction; (2) analysis, in which the current/potential characteristics of an electrode are used to determine the type and concentration of a species; and (3) power generation. These broad types of applications require stable, conductive, chemically robust, and economical electrodes. Diamond electrodes, fabricated by chemical vapor deposition, provide electrochemists with an entirely new type of carbon electrode that meets these requirements for a wide range of applications.The first reports of electrochemical studies using diamond were in the mid-1980s. During the past several years, the field has attracted increasing attention. This review summarizes the electrochemical properties of diamond that make it a unique electrode material and that distinguish it from conventional carbon electrodes.
TL;DR: In this paper, the state of the art in hard coatings for carbide cutting tools including discussion of coating characteristics and applications is presented, as well as a detailed discussion of their application.
Abstract: The majority of carbide cutting tools in use today employ hard coatings because coatings offer proven benefits in terms of tool life and machining performance. Continuing development of the chemical vapor deposition (CVD) coating process, the most widely used technique, has produced complex multilayer coatings tailored for specific applications and workpiece materials. These coatings include alumina layers of different crystal structures, and TiCN layers applied by high- or moderate-temperature (MT-CVD) processes. Over the last decade, coatings applied by physical vapor deposition (PVD) have gained acceptance in applications requiring sharp edges or those featuring interrupted cuts. Originally limited to TiN coatings, the PVD offering now includes TiCN and TiA1N coatings which provide better high-speed performance and increased abrasive wear resistance. In the area of superhard coatings, improvements in deposition processes and coating adhesion have resulted in diamond-coated carbide tools that have begun to play an important role in machining non-ferrous and non-metallic materials. This paper presents the state of the art in hard coatings for carbide cutting tools including discussion of coating characteristics and applications.
TL;DR: In this paper, a processing route has been developed to grow bundles of carbon nanotubes on substrates from methane and hydrogen mixtures by microwave plasma-enhanced chemical vapor deposition, catalyzed by iron particles reduced from ferric nitrate.
Abstract: A processing route has been developed to grow bundles of carbon nanotubes on substrates from methane and hydrogen mixtures by microwave plasma-enhanced chemical vapor deposition, catalyzed by iron particles reduced from ferric nitrate. Growth takes place at about 900 °C leading to nanotubes with lengths of more than 20 μm and diameters on the nanometer scale.
TL;DR: In this paper, phase pure nanotube films were grown on silicon substrates by a microwave plasma under conditions which normally are used for the growth of chemical vapor deposited diamond films, but instead of using any pretreatment leading to diamond nucleation, they deposited metal clusters on the silicon substrate.
Abstract: Phase pure nanotube films were grown on silicon substrates by a microwave plasma under conditions which normally are used for the growth of chemical vapor deposited diamond films. However, instead of using any pretreatment leading to diamond nucleation we deposited metal clusters on the silicon substrate. The resulting films contain only nanotubes and also onion-like structures. However, no other carbon allotropes like graphite or amorphous clustered material could be found. The nanotubes adhere very well to the substrates and do not need any further purification step. Electron field emission was observed at fields above 1.5 V/μm and we observed an emission site density up to 104/cm2 at 3 V/μm. Alternatively, we have grown nanotube films by the hot filament technique, which allows to uniformly cover a two inch wafer.
TL;DR: In this article, a list of gas-phase and surface reactions has been compiled for modeling plasma-enhanced chemical vapor deposition of SiO2 from SiH4, O2, and Ar gas mixtures in high-density-plasma reactors.
Abstract: High-density-plasma deposition of SiO2 is an important process in integrated circuit manufacturing A list of gas-phase and surface reactions has been compiled for modeling plasma-enhanced chemical vapor deposition of SiO2 from SiH4, O2, and Ar gas mixtures in high-density-plasma reactors The gas-phase reactions include electron impact, neutral–neutral, ion–ion, and ion–neutral reactions The surface reactions and deposition mechanism is based on insights gained from attenuated total reflection Fourier transform infrared spectroscopy experiments and includes radical adsorption onto the SiO2 surface, ion-enhanced desorption from the surface layer, radical abstractions, as well as direct ion-energy-dependent sputtering of the oxide film A well-mixed reactor model that consists of mass and energy conservation equations averaged across the reactor volume was used to model three different kinds of high-density plasma deposition chambers Experimental measurements of total ion densities, relative radical dens
TL;DR: In this paper, thin films of antimony sulfide have been deposited from chemical baths containing antimony trichloride and sodium thiosulfate maintained at 10 C. Upon annealing in nitrogen at 300 C for 1 h, the films become photosensitive with photo-to-dark-current ratio of two to three orders of magnitude at 2 kW/m{sup 2} tungsten halogen radiation.
Abstract: Thin films of antimony sulfide have been deposited from chemical baths containing antimony trichloride and sodium thiosulfate maintained at 10 C. Upon annealing in nitrogen at 300 C for 1 h, the films become photosensitive with photo- to dark-current ratio of two to three orders of magnitude at 2 kW/m{sup 2} tungsten halogen radiation. The annealed films are crystalline with an X-ray diffraction pattern matching that of stibnite, Sb{sub 2}S{sub 3}, (JCPDS 6-0474) and show an optical bandgap of 1.78 eV. Deposition of a thin film of CuS on the antimony sulfide thin film and subsequent annealing in nitrogen at 250 C for 1 h produces films with acceptable solar control characteristics: integrated visible transmittance, T{sub vis}, 15%; integrated visible reflectance, R{sub vis}, 12%; integrated infrared transmittance, T{sub ir}, 14%; integrated infrared reflectance, R{sub ir}, 36%; and a shading coefficient of about 0.35. The X-ray diffraction patterns of the annealed Sb{sub 2}S{sub 3}-CuS thin films indicate the formation of a ternary compound with the structure of famatinite, Cu{sub 3}SbS{sub 4}.
TL;DR: In this paper, the influence of the deposition parameters (temperature, total pressure and NH3/SiH4 gaseous ratio) on the film deposition rate, refractive index, stoichiometry and thermomechanical stress are investigated and correlated.
Abstract: Varied SiNx films have been deposited by low pressure chemical vapor deposition from silane SiH4 and ammonia NH3 and the influences of the deposition parameters (temperature, total pressure and NH3/SiH4 gaseous ratio) on the film deposition rate, refractive index (assessed at a 830 nm wavelength), stoichiometry and thermomechanical stress are investigated and correlated. Low stress (≈600 MPa) Si3N4 films are obtained for the highest deposition temperature and the lowest total pressure but the gaseous ratio is shown to be the dominant parameter. According to the SiNx stoichiometry, silicon-rich silicon nitride and nitrogen-doped silicon (called NIDOS) depositions are obtained and compressive to tensile stresses are reported. A maximum in compressive stress is put into evidence for N/Si ratio roughly equal to 0.7 and is related to the cumulated effects of silicon nitridation and crystallization, characterizing the transition between nitrogen-doped silicon and silicon-rich silicon nitride. Finally, by consid...