Chemical Vapor Deposition Research Papers (original) (raw)

Carbon Nanotubes are one the most important materials of future. Discovered in 1991, they have reached a stage of attracting the interests of many companies world wide for their large scale production. They possess remarkable electrical,... more

Carbon Nanotubes are one the most important materials of future. Discovered in 1991, they have reached a stage of attracting the interests of many companies world wide for their large scale production. They possess remarkable electrical, mechanical, optical, thermal and chemical properties, which make them a perfect “fit” for many engineering applications. In this paper various methods of production of carbon nanotubes are discussed outlining their capabilities, efficiencies and possible exploitation as economic large scale production methods. Chemical vapor disposition (CVD) is proposed as a potential method for economic large scale production of carbon nanotubes due to its relative simplicity of operation, process control, energy efficiency, raw materials used, capability to scale up as large unit operation, high yield and purity.

Thesize effect of nanoscale silicon in both amorphous and porous silicon was investigated with micro­Raman spectroscopy. Silicon nanostructers in amorphous silicon were deposited on quartz substrates by plasma enhanced chemical vapor... more

Thesize effect of nanoscale silicon in both amorphous and porous silicon was investigated with micro­Raman spectroscopy. Silicon nanostructers in amorphous silicon were deposited on quartz substrates by plasma enhanced chemical vapor deposition (PECVD) with deposition powers of 15, 30 and 50W. Micro­Raman spectra of the nanostructured silicon show the T 2g Raman active mode shifting from the 521 cm ­1 crystalline Si Raman line to 494, 499 and 504 cm ­1 as deposition power increased. Large Raman mode shifts, up to 27 cm ­1 and broadening up to 23 cm ­1 of the T 2g Raman­active mode is attributed to a phonon confinement effect which {did what with power}. The analysis of micro­Raman scattering data is useful to understand the role of deposition condition of the silicon sample. In addition, enhanced micro­Raman scattering intensity of porous silicon prepared using double cell electrochemical etching through various current densities such as 10, 50 and 125 mA/cm 2 has also been investigated. The effect of phonon confinement on the nanoscale porous silicon has been quantified. The relationship between Raman shift and stress on the porous silicon has been evaluated.

Recent progress with indium (III) sulfide (In2S3)-buffered thin film solar cells (TFSC) was briefly reviewed. In2S3 has emerged as a promising low-hazard buffer (or window) material, and has proven to improve the properties of the solar... more

Recent progress with indium (III) sulfide (In2S3)-buffered thin film solar cells (TFSC) was briefly reviewed. In2S3 has emerged as a promising low-hazard buffer (or window) material, and has proven to improve the properties of the solar cells, while reducing toxicity. Various deposition techniques have been employed to synthesize In2S3 films on different types of substrates. Until now, atomic layer deposition (ALD) and ionic layer gas atomic reaction (ILGAR) techniques have been the two most successful, yielding maximum energy conversion efficiencies up to 16.4% and 16.1%, respectively. The impact of varied deposition parameters upon the In2S3 film properties and performance of cadmium (Cd)-free solar cells has been outlined. A comparative/operational analysis (solar cell efficiencies above 9% reported for cell area ≤ 1cm2) of various buffer layers used in two primary types of TFSC technology: chalcopyrite (CIS/CIGS)- and CdTe-based solar cells was also performed to measure the progress of In2S3 compared to its counterparts.

This article provides an overview of the state-of-the-art chemistry and processing technologies for silicon nitride and silicon nitride-rich films, i.e., silicon nitride with C inclusion, both in hydrogenated (SiN x :H and SiN x :H(C))... more

This article provides an overview of the state-of-the-art chemistry and processing technologies for silicon nitride and silicon nitride-rich films, i.e., silicon nitride with C inclusion, both in hydrogenated (SiN x :H and SiN x :H(C)) and non-hydrogenated (SiN x and SiN x (C)) forms. The emphasis is on emerging trends and innovations in these SiN x material system technologies, with focus on Si and N source chemistries and thin film growth processes, including their primary effects on resulting film properties. It also illustrates that SiN x and its SiN x (C) derivative are the focus of an ever-growing research and manufacturing interest and that their potential usages are expanding into new technological areas.

The need for tighter control over film uniformity, conformality, and properties at decreasing thicknesses was met by a gradual evolution from physical vapor deposition (PVD), to chemical vapor deposition (CVD), and eventually atomic layer... more

The need for tighter control over film uniformity, conformality, and properties at decreasing thicknesses was met by a gradual evolution from physical vapor deposition (PVD), to chemical vapor deposition (CVD), and eventually atomic layer deposition (ALD) processes. Of all manufacturing-worthy thin-film deposition processes, ALD has the greatest potential to satisfy these requirements. However, the intrinsic constraints of recurrent two atom reactivity and associated byproducts have kindled tremendous interest in other self-limiting deposition processes such as Molecular Layer Deposition (MLD), Self-Assembled Monolayer (SAM), and “Click” Chemistry Deposition (CCD) processes, either as alternatives to or in conjunction with ALD. This overview provides definitions, illustrations and examples of these processes.

We report catalyst-free growth of high-density single-sided ZnO nanocombs for the first time on a multi-layer graphene (MLG). Structural analysis based on scanning electron microscope reveal the nanocomb ribbon average diameter and length... more

We report catalyst-free growth of high-density single-sided ZnO nanocombs for the first time on a multi-layer graphene (MLG). Structural analysis based on scanning electron microscope reveal the nanocomb ribbon average diameter and length are about 90-600 nm and 5-60 μm, respectively, while the diameter and length of the comb tooth are about 30 -100 nm and 100-700 nm respectively. In general, the length of the teeth decreases gradually from one end of the nanocomb ribbon to another. ZnO crystal growth seems to involve two steps which are the formation of Zn buffer layer/graphene, which works as growth nucleation sites and long nanowires ends with nanocombs structure. Raman and PL optical transitions prove the well-faceted hexagonal structure of ZnO nanocombs as well as existence of defects such as O vacancies and Zn interstitials. Graphene-based inorganic hybrid nanostructures provide several potential applications in optoelectronics and nanoscale electronics such as nanogenerators, photovoltaic devices, optical devices, and photodetectors.

The chemical vapor deposition (CVD) of metals is a rapidly developing area in which metal-containing compounds are being synthesized as new precursors. This article reviews this area and discusses precursor design, reaction pathways,... more

The chemical vapor deposition (CVD) of metals is a rapidly developing area in which metal-containing compounds are being synthesized as new precursors. This article reviews this area and discusses precursor design, reaction pathways, reactor types, and the influence of reactor operating conditions on film growth. We have gathered recent results for precursor design and CVD chemistry and show how analysis of results from CVD experiments can be used to assist in the development of new CVD precursors.

Iron is a widely used catalyst for the growth of carbon nanotubes (CNTs)/carbon nanofibers (CNFs) by catalytic chemical vapour deposition. However, both Fe and Fe-C compounds (generally, Fe3C) have been found to catalyze the growth of... more

Iron is a widely used catalyst for the growth of carbon nanotubes (CNTs)/carbon nanofibers (CNFs) by catalytic chemical vapour deposition. However, both Fe and Fe-C compounds (generally, Fe3C) have been found to catalyze the growth of CNTs/CNFs, and a comparison study of their respective catalytic activities is still missing. Furthermore, the control of the crystal structure of iron-based catalysts, that is α-Fe or Fe3C, is still a challenge, which not only obscures our understanding of the growth mechanisms of CNTs/CNFs, but also complicates subsequent procedures, such as the removal of catalysts for better industrial applications. Here, we show a partial control of the phase of iron catalysts (α-Fe or Fe3C), obtained by varying the growth temperatures during the synthesis of carbon-based nanofibers/nanotubes in a plasma-enhanced chemical vapour deposition reactor. Moreover, we directly compare the growth rates of carbon-based nanofibers/nanotubes during the same experiments and find that CNFs/CNTs grown by α-Fe nanoparticles are longer than CNFs/CNTs grown from Fe3C nanoparticles. The influence of the type of catalyst on the growth of CNFs is analyzed and the corresponding possible growth mechanisms, based on the different phases of the catalysts, are discussed.

Cobalt metallic films are the subject of an ever-expanding academic and industrial interest for incorporation into a multitude of new technological applications. This report reviews the state-of-the art chemistry and deposition techniques... more

Cobalt metallic films are the subject of an ever-expanding academic and industrial interest for incorporation into a multitude of new technological applications. This report reviews the state-of-the art chemistry and deposition techniques for cobalt thin films, highlighting innovations in cobalt metal-organic chemical vapor deposition (MOCVD), plasma and thermal atomic layer deposition (ALD), as well as pulsed MOCVD technologies, and focusing on cobalt source precursors, thin and ultrathin film growth processes, and the resulting effects on film composition, resistivity and other pertinent properties.

Chemical vapor deposition (CVD) of polymer films represent the marriage of two of the most important technological innovations of the modern age. CVD as a mature technology for growing inorganic thin films is already a workhorse... more

Chemical vapor deposition (CVD) of polymer films represent the marriage of two of the most important technological innovations of the modern age. CVD as a mature technology for growing inorganic thin films is already a workhorse technology of the microfabrication industry and easily scalable from bench to plant. The low cost, mechanical flexibility, and varied functionality offered by polymer thin films make them attractive for both macro and micro scale applications. This review article focuses on two energy and resource efficient CVD polymerization methods, initiated Chemical Vapor Deposition (iCVD) and oxidative Chemical Vapor Deposition (oCVD). These solvent-free, substrate independent techniques engineer multi-scale, multi-functional and conformal polymer thin film surfaces and interfaces for applications that can address the main sustainability challenges faced by the world today.

En este experimento se determinó la presión de vapor de un líquido que en este caso fue el agua, utilizando la relación presión y temperatura. Se evalúo diferentes temperaturas para calcular la entalpía de vaporización del líquido usado a... more

En este experimento se determinó la presión de vapor de un líquido que en este caso fue el agua, utilizando la relación presión y temperatura. Se evalúo diferentes temperaturas para calcular la entalpía de vaporización del líquido usado a partir de la ecuación de Clausius-Clapeyron, que permite graficar los datos de uno sobre la temperatura y el logaritmo natural de la presión del agua, datos que se obtuvieron a partir de diferentes ecuaciones con datos arrojados por el experimento. Los valores obtenidos en la práctica determinó una entalpía de vaporización del agua​ ​ de​ ​ 795,127​ ​ cal/gr​ ​ con​ ​ un​ ​ porcentaje​ ​ de​ ​ error​ ​ del​ ​ 47,25%. ABSTRACT In this experiment, the vapor pressure of a liquid, which in this case was water, was determined using the pressure and temperature relationship. Different temperatures were evaluated to calculate the enthalpy of vaporization of the liquid used from the Clausius-Clapeyron equation, which allows graphing the data of one on the temperature and the natural logarithm of the water pressure, data that were obtained from different equations with data thrown by the experiment. The values obtained in practice determined an enthalpy of vaporization of water of 795,127 cal/gr​ ​ with​ ​ an​ ​ error​ ​ rate​ ​ of​ ​ 47.25%.

A synthetic method is presented for the production of isotetrasilane, a higher order perhydridosilane, with the purity and volume necessary for use in extensive studies of the chemical vapor deposition (CVD) of epitaxial silicon (e-Si)... more

A synthetic method is presented for the production of isotetrasilane, a higher order perhydridosilane, with the purity and volume necessary for use in extensive studies of the chemical vapor deposition (CVD) of epitaxial silicon (e-Si) thin films. The chemical characteristics, thermodynamic properties and epitaxial film growth of isotetrasilane are compared with those of other perhydridosilanes. A film-growth mechanism distinct from linear perhydrodosilanes H(SiH2)nH, where n is ≤4, is re-ported. Preliminary findings are summarized for CVD of both unstrained e-Si and strained e-Si doped with germanium (Ge) and carbon (C) employing isotetrasilane as the source precursor at temperatures of 500-550C. The results suggest that bis(trihydridosilyl)silylene is the likely deposition intermediate under processing conditions in which gas-phase depletion reactions are not observed.

The large scale production of carbon nanotubes (CNTs) is a major issue for their use in industry. Among the different techniques used for their synthesis, catalytic (C)CVD in fluidized-bed reactors appears one of the most promising. In... more

The large scale production of carbon nanotubes (CNTs) is a major issue for their use in industry. Among the different techniques used for their synthesis, catalytic (C)CVD in fluidized-bed reactors appears one of the most promising. In this article we present the current state of this new technology and we aim to highlight its great flexibility through examples which depict the selective preparation of different kinds of carbon nanomaterials from different catalysts. Finally, we present the results of scale-up experiments that permit an increase in carbon nanotube production by two orders of magnitude.

The vapor phase deposition of polymeric antimicrobial coatings is reported. Initiated chemical vapor deposition (iCVD), a solventless low-temperature process, is used to form thin films of polymers on fragile substrates. For this work,... more

The vapor phase deposition of polymeric antimicrobial coatings is reported. Initiated chemical vapor deposition (iCVD), a solventless low-temperature process, is used to form thin films of polymers on fragile substrates. For this work, finished nylon fabric is coated by iCVD with no affect on the color or feel of the fabric. Infrared characterization confirms the polymer structure. Coatings of poly(dimethylaminomethyl styrene) of up to 540 μg/cm2 were deposited on the fabric. The antimicrobial properties were tested using standard method ASTM E2149-01. A coating of 40 μg/cm2 of fabric was found to be very effective against gram-negative Escherichia coli, with over a 99.99%, or 4 log, kill in just 2 min continuing to over a 99.9999%, or 6 log, reduction in viable bacteria in 60 min. A coating of 120 μg/cm2 was most effective against the gram-positive Bacillus subtilis. Further tests confirmed that the iCVD polymer did not leach off the fabric.

Zinc sulphide thin films were prepared by chemical bath deposition (CBD) and the properties of these films are compared with those deposited by Physical vapour deposition (PVD). The variation in the optical and electrical properties of... more

Zinc sulphide thin films were prepared by chemical bath deposition (CBD) and the properties of these films are compared with those deposited by Physical vapour deposition (PVD). The variation in the optical and electrical properties of the CBD grown ZnS films with the pH of the reaction mixture was investigated. The chemically deposited ZnS films showed a wide band gap of 3.93eV and a transparency of more than 80% in the visible region. The lowest resistivity of ~104 Ωcm was obtained for the films prepared from a chemical bath of pH 10.6. The refractive index, extinction coefficient and the dielectric constants of CBD ZnS films are also reported.

In this study the efficiency of electrochemical oxidation of aromatic pollutants, such as reactive dyes, at boron-doped diamond on silicon (Si/BDD) electrodes was investigated. The level of [B]/[C] ratio which is effective for the... more

In this study the efficiency of electrochemical oxidation of aromatic pollutants, such as reactive dyes, at boron-doped
diamond on silicon (Si/BDD) electrodes was investigated. The level of [B]/[C] ratio which is effective for the degradation and
mineralization of selected aromatic pollutants, and the impact of [B]/[C] ratio on the crystalline structure, layer conductivity and
relative sp3/sp2 coefficient of a BDD electrode were also studied. The thin film microcrystalline electrodes have been deposited on
highly doped silicon substrates via MW PE CVD. Si/BDD electrodes were synthesized for different [B]/[C] ratios of the gas phase.
Mechanical and chemical stability of the electrodes was achieved for the microcrystalline layer with relatively high sp3/sp2 band
ratio. Layer morphology and crystallite size distribution were analyzed by SEM. The resistivity of BDD electrodes was studied
using four-point probe measurements. The relative sp3/sp2 band ratios were determined by deconvolution of Raman and X-ray photoelectron spectra. The efficiency of degradation and mineralization of the reactive azo dye rubin F-2B was estimated based on the absorbance measurements at 545 nm. The influence of commonly used electrolytes NaCl and Na2SO4 on the dye removal efficiency was also investigated. The results suggest that, in general, the oxidation occurs indirectly at the anode through generation of hydroxyl radicals •OH, which react with the dye in a very fast and non-selective manner. In NaCl electrolyte the dye was also
decomposed by more selective, active chlorine species (Cl2, HOCl). However the efficiency of this process in BDD depended on the electrode's doping level. Higher amounts of dopant on the surface of BDD resulted in the higher efficiency of dye removal in both electrolytes.

A stagnation point cold-wall reactor was used for the CVD of corundum alumina (α-Al2O3) on metallic substrates. Depositions were carried out under low pressure using the thermally induced pyrolytic oxidation of aluminum tri-isopropoxide... more

A stagnation point cold-wall reactor was used for the CVD of corundum alumina (α-Al2O3) on metallic substrates. Depositions were carried out under low pressure using the thermally induced pyrolytic oxidation of aluminum tri-isopropoxide (ATI). The effects of the substrate temperature (300–1080 °C) and the total pressure (50–250 mbar) on the growth rate and morphology of the deposits were investigated. An excess of oxygen facilitates the formation of dense alumina films. Precursor depletion was prevented using high gas velocity, low ATI concentration, and a high temperature gradient. X-ray diffraction (XRD) analysis provided evidence of corundum alumina deposition at substrate temperatures above 1000 °C.

The remarkable properties of carbon nanotubes (CNTs) make them attractive for microelectronic applications, especially for interconnects and nanoscale devices. In this paper, we describe a microelectronics compatible process for growing... more

The remarkable properties of carbon nanotubes (CNTs) make them attractive for microelectronic applications, especially for interconnects and nanoscale devices. In this paper, we describe a microelectronics compatible process for growing high-aspect-ratio CNT arrays with application to vertical electrical interconnects. A lift-off process was used to pattern catalyst (Al2O3/Fe) islands to diameters of 13 or 20 μm. After patterning, chemical vapor deposition (CVD) was involved to deposit highly aligned CNT arrays using ethylene as the carbon source, and argon and hydrogen as carrier gases. The as-grow CNTs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the CNTs have high purity, and form densely-aligned arrays with controllable array size and height. Two-probe electrical measurements of the CNT arrays indicate a resistivity of ∼0.01 Ω cm, suggesting possible use of these CNTs as interconnect materials.