Download or read book Atomic Layer Controlled Deposition of Thin Films Using Sequential Surface Reactions written by Jason Wells Klaus and published by . This book was released on 1999 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of the Initial Surface Reactions in Atomic Layer Deposition of Oxides Silicides and Nitrides Thin Films on Silicon Substrates written by Karla Maria Bernal Ramos and published by . This book was released on 2014 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, key aspects of the surface chemistry associated with atomic layer deposition (ALD) are discussed. ALD is a novel and promising film deposition technique that can deliver precise thickness control at the angstrom or monolayer level; the self-limiting aspect of ALD makes it a unique method that can lead to excellent step coverage and conformal deposition on high aspect ratio structures. In spite of its central role in efficient film deposition processes, little is known about the mechanisms of the chemical reactions involved. Even the most basic information, such as the initial surface reactions, is in many instances unknown. There is a limited knowledge on the surface chemistry (e.g., substrate, precursor's reactivity) effects for the growth of the films. Reactivity in ALD is controlled by the nature of the substrate, where specific nucleation sites are often responsible for the initial deposition and where a change in chemistry may take place as the first layer of the growing film is formed. The precursor's reactivity towards the surface being used and its properties are fundamental aspects in an ALD process. The majority of the experiments discussed in this dissertation are devoted to the elucidation of the reaction mechanisms of the thin films. The experiments are carried out using in-situ Fourier transform infrared spectroscopy (FTIR) in order to examine the chemical composition of surface adsorbates. The use of in-situ characterization techniques is crucial for better control and understanding of thin film deposition. Knowledge of the surface chemistry underpinning the ALD processes is essential in order to design precursors in a rational way that will lead to successful film growth.
Download or read book Development and Applications of Oxide Thin Films Using Atomic Layer Deposition and Prompt Inorganic Condensation written by Sean Weston Smith and published by . This book was released on 2015 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the first part of this work, thin films of Al2O3 deposited via atomic layer deposition (ALD) are demonstrated to improve the thermal stability of cellulose nanocrystal (CNC) aerogels. ALD is a chemical vapor deposition (CVD) like method in which sequential precursor exposures and self-limited surface reactions produce a conformal thin film with precise thickness control. The conformal nature of ALD is well suited to coating the porous microstructure of aerogels. SEM micrographs of coating thickness depth profiles are shown to agree with trends predicted by precursor penetration models. Thermogravimetric analysis shows samples coated with ALD Al2O3 have increased decomposition temperatures. In the second part of this work, ALD zinc tin oxide (ZTO) is used to demonstrate a technique for measuring the substrate inhibited growth in multicomponent and laminate ALD systems. The thickness control of ALD makes it attractive for multicomponent and laminate systems. However, the surface reactions of ALD mean that the first few cycles, while the film nucleates, may have a different growth per cycle (GPC) than when the film is growing on itself in a bulk growth regime. A model for the substrate inhibited ALD of ZTO is derived from two complementary sets of laminates. The thickness and composition predictions of our model are tested against the bulk GPC of ZnO and SnO2. In the final part of this work, prompt inorganic condensation (PIC) is explored as a potentially more environmentally friendly alternative to ALD for planar thin film applications. Whereas ALD requires expensive vacuum systems and has low precursor utilization, solution based methods, such as PIC, allow atmospheric processing and precursor recycling. The water based PIC solutions use nitrate counter ions which evaporate at low temperatures. Combined with the low energy required to convert the hydroxide precursor clusters into an oxide film makes PIC a promising low temperature route to dense solution processed thin films. The dielectric performance of PIC Al2O3 is shown to be comparable to ALD Al2O3 films on Si though a large interfacial SiO2 layer is found to be dominating the behavior of the PIC films. This interfacial layer is shown to form very quickly (≤ 2 min) at low temperatures (≤ 50°C). This low temperature interfacial oxide growth could be a benefit in passivating solar cells.
Download or read book Atomic Layer Deposition for Semiconductors written by Cheol Seong Hwang and published by Springer Science & Business Media. This book was released on 2013-10-18 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offering thorough coverage of atomic layer deposition (ALD), this book moves from basic chemistry of ALD and modeling of processes to examine ALD in memory, logic devices and machines. Reviews history, operating principles and ALD processes for each device.
Download or read book Engineering Particle Surface Chemistry and Electrochemistry with Atomic Layer Deposition written by David Hyman Kentaro Jackson and published by . This book was released on 2017 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomic layer deposition (ALD) is a vapor phase thin film coating technique that relies on sequential pulsing of precursors that undergo self-limited surface reactions. The self- limiting reactions and gas phase diffusion of the precursors together enable the conformal coating of microstructured particles with a high degree of thickness and compositional control. ALD may be used to deposit thin films that introduce new functionalities to a particle surface. Examples of new functionalities include: chemical reactivity, a mechanically strong protective coating, and an electrically resistive layer. The coatings properties are often dependent on the bulk properties and microstructure of the particle substrate, though they usually do not affect its bulk properties or microstructure. Particle ALD finds utility in the ability to synthesize well controlled, model systems, though it is expensive due to the need for costly metal precursors that are dangerous and require special handling. Enhanced properties due to ALD coating of particles in various applications are frequently described empirically, while the details of their enhancement mechanisms often remain the focus of ongoing research in the field. This study covers the various types of particle ALD and attempts to describe them from the unifying perspective of surface science.
Download or read book Handbook of Deposition Technologies for Films and Coatings written by Peter M. Martin and published by William Andrew. This book was released on 2009-12-01 with total page 932 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 3e, edited by Peter M. Martin, PNNL 2005 Inventor of the Year, is an extensive update of the many improvements in deposition technologies, mechanisms, and applications. This long-awaited revision includes updated and new chapters on atomic layer deposition, cathodic arc deposition, sculpted thin films, polymer thin films and emerging technologies. Extensive material was added throughout the book, especially in the areas concerned with plasma-assisted vapor deposition processes and metallurgical coating applications.
Download or read book Handbook of Manufacturing Engineering and Technology written by Andrew Y. C. Nee and published by Springer. This book was released on 2014-10-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Springer Reference Work Handbook of Manufacturing Engineering and Technology provides overviews and in-depth and authoritative analyses on the basic and cutting-edge manufacturing technologies and sciences across a broad spectrum of areas. These topics are commonly encountered in industries as well as in academia. Manufacturing engineering curricula across universities are now essential topics covered in major universities worldwide.
Download or read book Atomic Layer Deposition of Nanostructured Materials written by Nicola Pinna and published by John Wiley & Sons. This book was released on 2012-09-19 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomic layer deposition, formerly called atomic layer epitaxy, was developed in the 1970s to meet the needs of producing high-quality, large-area fl at displays with perfect structure and process controllability. Nowadays, creating nanomaterials and producing nanostructures with structural perfection is an important goal for many applications in nanotechnology. As ALD is one of the important techniques which offers good control over the surface structures created, it is more and more in the focus of scientists. The book is structured in such a way to fi t both the need of the expert reader (due to the systematic presentation of the results at the forefront of the technique and their applications) and the ones of students and newcomers to the fi eld (through the first part detailing the basic aspects of the technique). This book is a must-have for all Materials Scientists, Surface Chemists, Physicists, and Scientists in the Semiconductor Industry.
Download or read book Atomic Layer Deposition for Surface Modifications and Solid Film Fabrication written by Haoming Yan and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Along with the unceasing development of the surface and material science, modification of substrates surfaces in nanoscale, to fabricate the functional materials with precisely controlled dimensions, refined composition and desired properties becomes crucial. In this report, atomic layer deposition (ALD), a vapor phase, sequential and self-limiting deposition process, has been used as an alternative strategy to modify the surface of materials and fabricates nanometer or micrometer level of functional materials with precise control. In the first part of this dissertation, ALD was used to modify the surface of the shape-engineered nanocrystals (SENCs), which enhanced the thermal stability of the SENCs from 300?C to 700?C and enhanced the catalytic activities of the nanocrystals as well. We also proposed a new reaction mechanism of metal-organic precursor with oxide surface, in which the conventional layered ALD growth does not happen but the oxide surface was modified via controlled metal doping. In the second part of this dissertation, ALD precursors were used to reacting with liquid substrates to fabricate freestanding solid thin films. Benefits from the unique reaction mechanism of the ALD metal-organic precursors, the thickness and the compositions of the fabricated films can be controlled. The fundamental of gas-liquid reaction has been discussed in this study. In the third part of this dissertation, area-selective ALD (AS-ALD) has been reported using carboxylic acid self-assembled monolayer as a growth inhibitor. Excellent selectivity of AS-ALD has been achieved by using this method, which could potentially be used in microfabrication as a substitution step for photolithography.
Download or read book Atomic Layer Deposition of Materials for Electronic and Photonic Applications written by Francis Chalvet and published by . This book was released on 2008 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomic Layer Deposition (ALD) is a technique to deposit extremely uniform thin films through surface-controlled reactions of gaseous precursors. It is the method of choice for ultrathin oxide and metal layers in the next generations of logic and memory devices, but finds application as well in nanotechnology and catalysis. An ALD reactor at laboratory scale was designed and built to study the growth of metal oxides such as Al2O3 and HfO2 on flat and porous surfaces. During the design of the process, the key aspects were the choice of two complementary chemical precursors and the time controlled injection of precursor fluxes into the deposition chamber. After assembly of the reactor the operation parameters (pressure, nitrogen throughput, precursor fluxes) were optimised. The reactor worked at vacuum pressures of about 1 torr and used a continuous flow of nitrogen for the transport of precursor gases. Uniform and controlled film growth was observed during growth of Al2O3 from trimethylaluminium and water, and during growth of HfO2 from hafnium-tetrakisdimethylamide and water. Electrical characterisation of MOS capacitors with a Pd/HfO2/Si structure and 3 or 9 nm thin layers of HfO2 showed the high quality of the insulating oxide. The deposition technique was then used to coat porous structures. Membranes with high aspect ratios pores (L/d = 300) were coated with HfO2 without modifying the process used for coating flat surfaces. The possibility offered by ALD to coat pores with a high level of control was used to tune the optical characteristics of porous photonic crystals. Opal-type photonic crystals were infiltrated with layers of Al2O3, TiO2 and VOx. The results obtained show the deposition of high quality oxide films with a thickness controllable at the nanoscale, on both flat and porous surfaces.
Download or read book Atomic Layer Deposition Applications 5 written by S. de Gendt and published by The Electrochemical Society. This book was released on 2009-09 with total page 425 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomic Layer Deposition can enable precise deposition of ultra-thin, highly conformal coatings over complex 3D topography, with controlled composition and properties for a wide range of applications.
Download or read book Atomic Layer Deposition written by David Cameron and published by MDPI. This book was released on 2020-12-28 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomic layer deposition (ALD) is a thin film deposition process renowned for its ability to produce layers with unrivaled control of thickness and composition, conformability to extreme three-dimensional structures, and versatility in the materials it can produce. These range from multi-component compounds to elemental metals and structures with compositions that can be adjusted over the thickness of the film. It has expanded from a small-scale batch process to large scale production, also including continuous processing – known as spatial ALD. It has matured into an industrial technology essential for many areas of materials science and engineering from microelectronics to corrosion protection. Its attributes make it a key technology in studying new materials and structures over an enormous range of applications. This Special Issue contains six research articles and one review article that illustrate the breadth of these applications from energy storage in batteries or supercapacitors to catalysis via x-ray, UV, and visible optics.
Download or read book Atomic Layer Control of Thin Film Growth Using Binary Reaction Sequence Chemistry written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our research is focusing on the atomic layer control of thin film growth. Our goal is to deposit films with precise control of thickness and conformality on both flat and high aspect ratio structures. Atomic layer control of growth is crucial for many technologies that require nanoscale deposition techniques to fabricate ultrathin and conformal films with thicknesses from 10-100 A. Examples of these films are ultrathin gate oxides, high dielectric constant films, conformal transparent conducting layers and ultrathin diffusion barriers.
Download or read book Atomic Layer Deposition ALD written by Callisto Joan MacIsaac and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern society demands smaller, more precise devices for both microelectronic and energy technologies. The development of methods and processes that can deposit reliably uniform, conformal thin films on the nanoscale is essential to fields as diverse as catalysts and solar cells. Therefore, atomic layer deposition (ALD), a thin-film deposition technique that accomplishes these goals by using self-limiting sequential reactions between alternating precursors to achieve atomic precision over the product film, is an important tool for the modern era. Combining ALD with molecular layer deposition (MLD), which follows the same principles as ALD but deposits entire organic molecules to build films, results in a powerful system that enables the deposition of inorganic, organic, and hybrid inorganic-organic materials. Understanding the nucleation mechanisms, surface reaction chemistry, and applications of these materials and ALD/MLD processes is essential to commercialization and wider use. Through in situ Fourier transform infrared (FTIR) spectroscopy, we studied the zinc-tin-oxide (ZTO) system, a ternary ALD process that is a combination of the zinc oxide and tin oxide binary ALD processes. Previous research had indicated that the ternary system is characterized by non-idealities in the ALD growth, and we identify as a potential cause of these effects incomplete removal of the ligands from the tetrakis(dimethylamino)tin precursor, which leads to a nucleation delay when depositing ZnO on SnO2. A significant fraction of the ligands remain on the surface during the ALD of SnO2 and endure when the process is switched to ZnO ALD. This result suggests that the occupation of surface reactive sites by these persisting ligands may be the cause of the observed nucleation delay with potential ramifications for many other binary and ternary systems where persisting ligands may be present. In addition, we studied the mechanism of ALD-grown MoS2 thin films. It was observed by atomic force microscopy (AFM), grazing incidence small angle X-ray scattering (GISAXS), and X-ray reflectivity (XRR) that nucleation proceeds by the formation of small islands that coalesce into a complete film in under 100 cycles, with further film growth failing to occur after coalescence. This inertness is attributed to the chemical inactivity of the basal planes of MoS2. It was found that the final thickness of the as-grown film is not determined by the number of ALD cycles as per the normal regime, but by the temperature that the film is deposited at. This self-limiting layer synthesis (SLS) has been reported in the literature for higher temperature depositions of MoS2, but this is the first report of the effect in a low temperature, amorphous MoS2 ALD system. The thickness of films growth by ALD with the precursors Mo(CO)6 and H2S was found to saturate at around 7 nm on both native oxide-covered silicon and bulk crystalline MoS2 substrates, which may indicate that the SLS behavior is inherent to the ALD process and not substantially a product of the substrate surface potential. Finally, we demonstrated a new ALD/MLD hybrid process that used the MoS2 ALD precursor Mo(CO)6 and the counter reagent 1,2-ethanedithiol to create a MoS2-like material with organic domains. This Mo-thiolate possesses many properties that link it to MoS2, such as activity towards the hydrogen evolution reaction (HER) and similar Raman modes, but has a significantly lower density, optical transparency, and higher geometric surface area. It was found that the process has a 1.3 Å growth per cycle and can catalyze the HER reaction at an overpotential of 294 mV at -10 mA/cm2 , which is superior to planar MoS2 and ranks the as-deposited catalyst with the best nanostructured MoS2-based catalysts. We propose that this activity comes from the higher surface area induced by the incorporation of organic chains into the films. In summary, we explored the mechanisms and nucleation behavior of several ALD systems of interest to energy applications using both in situ and ex situ analysis techniques. These studies demonstrated the importance of understanding ALD surface chemistry to the overall chemical composition of the resultant films, the ramifications of different nucleation regimes in determining morphologies, and the power of ALD/MLD in creating analogues to previously known species with improved physical properties.
Download or read book Designing Modeling Manufacturing and Testing an Atomic Layer Deposition System written by Mohamadamin Makarem and published by . This book was released on 2015 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are multiple techniques for depositing thin films in nanoelectronics and semiconductor industries. Each technique has its own advantage and disadvantage. Of the many techniques, chemical deposition is the most favorable since materials can be deposited in high aspect ratios and give full coverage across uneven surfaces. However the most conventional technique in chemical deposition, named chemical vapor deposition (CVD), has some limiting properties like high temperature and uncontrollable film growth. To have the advantage of chemical deposition and also being able to control film growth in monolayer resolution, a new technique has been introduced, named Atomic Layer Deposition (ALD). This technique gives a very good control on layer-bylayer film growth. It can work at low temperatures and high pressures. In manufacturing nanoantennas and MIM diodes there is a need, for having an ultra thin film with full coverage across select areas. ALD is a promising solution for ultra-thin film fabrication problems. In this work we designed, modeled, manufactured, and tested a novel ALD system. Our system is designed to do more exotic film depositions than the small-range accessible with industrially available ALDs. A typical ALD process starts with entraining a precursor in a carrier gas that brings it inside the reactor where it adsorbs on the substrate’s surface. The second step is removing the extra precursor from the chamber by purging it. The third step is adding another precursor gas to the reactor. The two precursors will react with each other on the substrate’s surface. In the fourth step a purge is used to remove excessive precursors and by-products from the reactor chamber. A well-designed reactor for this process needs to have the ability to operate under high vacuum, high temperatures, and intense reactions. In the designed reactor within this project, a showerhead, a stage heater, a ceramic spacer, and stage holder were designed and manufactured. There are four gas inlets from a top flange that feed into showerhead, which helps better gas dispersion. Also in the showerhead each of the inlets can be used to bring different gases inside the reactor for CVD processes. The designed reactor is a cross reactor, which minimizes the gas entrapment. All the flanges were designed in a way to have good ability to control the system. The tubing in this system is used to bring precursors inside the reactor. To have a good control on the flow rate of precursors, individual mass flow controllers, i.e. four ALD Solenoid Valves, are used to regulate the flow of each precursor. Bubblers are used to contain precursors at the entry point of the gas delivery line. Each bubbler has a dipping tube that extends the length of the bubbler container to give the carrier gas the ability to entrain precursors and bring them inside reactor. ALD Valve-4 is designed in a way that can switch the system from ALD to CVD. This gives us the ability to have multiple depositions in different techniques in a single run. ALD Valve-3 is designed for vacuum bubblers in case there is a precursor with very low volatility or very sensitive to high temperatures. Controlling the entire system, all at the same time, is crucial to the success of ALD. The parameters that needed to be controlled are temperature, pressure, gas flow, and each of the ALD Valves. There are five parts in the designed system that have separate thermocouples and heaters. Each of bubblers, tubings, the reaction chamber’s body, and substrate stage can get to a separate temperature using PID controllers. Finally a box designed for all the PID controllers and relays to read all the temperatures side-byside. In addition, there is a terminal box that connects all the tubings’ heaters and chamber heaters together. Low vacuum pressure can be read by either of the two thermocouple gauges installed on the system. One of the thermocouple gauges reads the pressure of the reaction chamber and the other reads the pressure inside turbopump. To control gas flow and ALD Valves, a software program was developed that can send digital signals to DAQ cards and the cards can change it to analog signal and send to MFCs and Valves. A control box is designed that contains all the four DAQ cards and a circuit that gives us the ability to control the valves by low currents. Finally the manufactured ALD was tested for process of depositing Al2O3 on top of silicon substrate. The test were performed in two batches, EDS test were performed to prove the deposition of Al2O3 also AFM test showed very flat films with 1.2 nm RMS were fabricated. The results of tests ensured the ability of the ALD to deposit films.
Download or read book Sequential Radical Enhanced Atomic Layer Deposition of Nanostructured Y2O3 Thin Films with Spatially Controlled Yb3 and Er3 Co doping for Optical Applications written by John Hoang and published by . This book was released on 2011 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Vapour Deposition written by Anthony C. Jones and published by Royal Society of Chemistry. This book was released on 2009 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The book is one of the most comprehensive overviews ever written on the key aspects of chemical vapour deposition processes and it is more comprehensive, technically detailed and up-to-date than other books on CVD. The contributing authors are all practising CVD technologists and are leading international experts in the field of CVD. It presents a logical and progressive overview of the various aspects of CVD processes. Basic concepts, such as the various types of CVD processes, the design of CVD reactors, reaction modelling and CVD precursor chemistry are covered in the first few"--Jacket
