Download or read book Surface Chemistry and Interface Evolution During the Atomic Layer Deposition of High k Metal Oxides on Inas 100 and Gaas 100 Surfaces written by Alex J. Henegar and published by . This book was released on 2015 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Device scaling has been key for creating faster and more powerful electronic devices. Integral circuit components like the metal-oxide semiconductor field-effect transistor (MOSFET) now rely on material deposition techniques, like atomic layer deposition (ALD), that possess atomic-scale thickness precision. At the heart of the archetypal MOSFET is a SiO2/Si interface which can be formed to near perfection. However when the thickness of the SiO2 layer is shrunk down to a few nanometers several complications arise like unacceptably high leakage current and power consumption. Replacing Si with III-V semiconductors and SiO2 with high-k dielectric materials is appealing but comes with its own set of challenges. While SiO2 is practically defect-free, the native oxides of III-Vs are poor dielectrics.
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 Atomic Scale Studies of Interface Formation Between Oxides and III V Semiconductor Surfaces written by Jonathon Boyd Clemens and published by . This book was released on 2010 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: The surface reconstructions of InAs(0 0 1)-(4 x 2) and In0.53Ga0.4--As(0 0 1)-(4 x 2) were investigated at 300 K and 80 K. At 300 K, the surfaces reconstruct to form the group III rich [beta]3'(4 x 2) reconstructions and at 80 K, the surfaces reconstruct to form the [beta]3'(4 x 4) reconstruction. A novel hybridization scheme is required for these reconstructions. Oxidation of the InAs(0 0 1)-(4 x 2) surface by O2 was studied and it was determined that this occurs via an autocatalytic process, displacing surface As. Oxidation is initiated on the group III rows of the surface, but the autocatalysis is in competition with a thermodynamic stability that limits the size of oxidation sites in the low coverage regime. Two methods for the formation of an interface between the high- & kappa; dielectric, HfO2 on InAs(0 0 1)-(4 x 2) and In0.53Ga0.4--As(0 0 1)-(4 x 2) were examined: reactive oxidation of Hf metal by O2 and electron beam deposition of HfO2. Reactive oxidation of Hf metal is problematic, but e− beam deposition of HfO2 showed that the p-type pinning behavior of In0.53Ga0.4--As(0 0 1)-(4 x 2) can be at least partially removed. Several oxygen atomic layer deposition (ALD) precursors were studied for the reaction (ALD initiation step) of high-[kappa] oxide growth on the InAs(0 0 1)-(4 x 2) surface : water, hydrogen peroxide, and isopropyl alcohol. All of these O precursors showed displacement reactions occurring on the III-V surfaces, but proceeded to varying degrees and by different pathways. Water displaces As, but does not fully oxidize it, HOOH etches the semiconductor surface at all temperatures, and isopropyl alcohol shows chemisorption site selectivity at 100 °C. The reaction of the ALD precursor, trimethyl aluminum (TMA) on InAs(0 0 1)-(4 x 2) and In0.53Ga0.4--As(0 0 1)-(4 x 2) was studied. An ordered, self-terminating single monolayer reaction occurs in the high coverage regime on both semiconductor surfaces. The p-type pinning behavior observed on the clean In0.53Ga0.4--As(0 0 1)-(4 x 2) surface is removed upon formation of the TMA-induced reaction; the surface was passivated for Al2O3 growth via metal-first ALD initiation. The major surface analytical techniques used were scanning tunneling microscopy and spectroscopy, low energy electron diffraction, Auger electron spectroscopy, and x-ray photoelectron spectroscopy.
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2018 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxide Surfaces written by James A. Wingrave and published by CRC Press. This book was released on 2019-10-16 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed treatment of information relating to fluid-oxide interfaces. It outlines methods for quantifying adsorption and desorption of polymeric and non-polymeric solutes at the gas- and solution-oxide interfaces. It also analyzes novel properties of oxide membranes and the synthesis and dissolution of oxide solids.
Download or read book GaAs 100 Surface Chemistry written by Scott M. Mokler and published by . This book was released on 1990 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important aspect in device technology is the processing of GaAs to produce highly-resolved etch patterns on the substrate. This is done typically on the GaAs(100) surface. Recently, a number of methods, all using chlorinated vapor reactants, have been applied to fabrication of GaAs devices. In spite of these technological advances, the understanding of the chemistry of the surface reaction on a fundamental level is still rudimentary. Practical etching involves a combination of chemical phenomenon and physical sputtering, in the presence of a mixture of chlorine containing gases to achieve material removal. The complexity of these processes precludes them as experiments for understanding the mechanisms responsible for etching. A simpler approach, used here, involves thermal etching and electron-induced desorption processes to study the material removed after a GaAs(100) surface is exposed to molecular chlorine. Another important aspect of device technology involves the atomic level interactions between metals and semiconductors as they are brought into contact. In this vein it has been found that sulfur containing compounds tend to lower the Schottky barrier height at the GaAs(100) surface, and thereby produce ohmic contacts at the metal-semiconductor interface. As with the GaAs/chlorine system, information on the GaAs/sulfur system is by no means conclusive. Molecular sulfur, hydrogen sulfide, as well as alkaline sulfides have all been used to deposit sulfur on the surface. This study concentrates on molecular sulfur and H2S and the very different behavior between the two upon adsorption and subsequent desorption from the GaAs(100) surface. These experiments on clean, chlorine and sulfur covered surfaces were all performed on well characterized GaAs(100) substrates either cleaned in situ by ion bombardment and annealing (IBA) techniques or grown in situ by molecular beam epitaxy (MBE). The information was gathered using standard surface science techniques under ultra-high vacuum (UHV) conditions. These techniques allow investigation of structure, composition and reaction present at the surface of materials.
Download or read book Ceramic Abstracts written by American Ceramic Society and published by . This book was released on 1996 with total page 1000 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomic Layer Deposition Applications 2 written by Ana Londergan and published by The Electrochemical Society. This book was released on 2007 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: This issue gives an overview of the cutting edge research in the various areas where Atomic Layer Deposition (ALD) can be used, enabling the identification of issues, challenges, and areas where further research is needed. Contributions include: Memory applications, Interconnects and contacts, ALD Productivity enhancement and precursor development, ALD for optical and photonic applications, and Applications in other areas, such as MEMs, nanotechnology, fabrication of sensors and catalysts, etc.
Download or read book External and Internal Surfaces in Metal Oxides written by L.C. Dufour and published by Trans Tech Publications Ltd. This book was released on 1988-01-01 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: Materials Science Forum Vol. 29
Download or read book In Situ Infrared Spectroscopy Study of Atomic Layer Deposition of High kappa Metal Oxide and Metal on Passivated Silicon Surfaces written by and published by . This book was released on 2008 with total page 199 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atomic layer deposition (ALD) is a novel and promising film deposition method for microelectronics and many other areas with documented commercial success. Notable advantages include accurate thickness control and high conformality, all of which are particularly important for deep trenches, porous materials and nanoparticles. The key elements of ALD including starting surfaces and precursors are investigated with in situ Fourier transform infrared spectroscopy, using a variety of starting surfaces: hydrogen-terminated Si (H/Si), oxidized Si, nitrided Si, and self-assembled monolayers (SAMs) grafted on H/Si surfaces. In particular, the formation of nitrided surfaces using thermal NH3 reaction with flat and vicinal H/Si(111) is studied and a mechanistic understanding is achieved with the aid of density functional theory calculation. An unexpected NH incorporated bridging structure is found at the dihydride step edge. The properties and stability of methyl and carboxylic groups terminated alkene-based SAMs grafted to H/Si(111) surface via direct Si-C bonds are also addressed. The carboxylic groups terminated SAM can be grafted without formation of interfacial SiO2. Moreover, the use of SiNx and SAM successfully minimizes the interfacial SiO2 during ALD process. With a thorough understanding of the starting surfaces, the nature of ALD grown high-kappa metal oxides and metal is studied. Water- and ozone-based ALD of HfO2 and Al2O3 are investigated mechanistically. Unexpected intermediate species and reaction pathways are found to depend on ozone partial pressure, such as formate intermediate for Al2O3 deposition. La2O3 and Cu deposited by novel precursors, La(iPr-MeAMD)3/D2O and [Cu(sBu-amd)]2/H2 respectively, are explored in many aspects such as the nature of precursor gas phase, the ALD temperature window, the film properties, and so on. In all cases, a mechanistic picture of the surface interaction and film growth is unraveled using infrared spectroscopy and other complementary techniques, such as Rutherford back scattering spectroscopy and X-ray photoelectron spectroscopy. Gas phase studies show that the two precursors are both readily hydrolyzed and highly reactive. ALD-deposited La2O3 films are of poor quality due to the hygroscopic nature of La2O3, and Cu diffusion and agglomeration are inferred from the evolution of IR vibrational modes.
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 1948 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomic Layer Deposition of High k Dielectrics on Germanium and Transition Metal Dichalcogenide written by Yuanxia Zheng and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two topics related to atomic layer deposition (ALD) have been studied in this thesis. One is the challenging task of integrating high-k dielectric on germanium (Ge) surface. The other is utilizing an ALD approach to synthesize transition metal dichalcogenide (TMD) of 1T-TaS2.The surface preparation primarily using in-situ H2 plasma to obtain pristine Ge surfaces has been investigated. The reaction mechanism and the resultant material properties have been examined carefully using in-situ and ex-situ metrologies. An optimized process has been proposed and resulted in an oxygen-free and atomically flat Ge surface. The nucleation behavior of Al2O3 ALD was investigated on Ge surfaces with two different chemicals states, hydrogenated and oxidized. The growth mode and the resultant dielectric/Ge interface properties have been clarified using in-situ and ex-situ metrologies. By comparing the experimental results with an atomic scale simulations (from collaborators), the reaction mechanism as well as the thermodynamic properties have been identified. A trilayer dielectric gate stack of HfO2/Al2O3/GeOx has been used to electrically test the aforementioned mechanisms of dielectric ALD on Ge. The optimum process has yielded a highly scaled Ge MOSCap device with superior interface qualities. 1T-TaS2 thin films has been synthesized using TaCl5 and H2S as the precursors in a home-made ALD system. A strong temperature dependence has been identified. A use of ultrathin Ta2O5 seed layer has been found beneficial to facilitate the nucleation of 1T-TaS2. ALD growth at a high temperature of 480 C has yielded the optimum results. Ferroelectric HfO2 has also been synthesized as the gate insulator for the future transistor fabrication using 1T-TaS2 as the channel material. A process flow for Al-doped HfO2 primarily using ALD approach in conjunction with magnetron sputtering has been developed. The electrical properties for various doping levels have evaluated using electrical polarization measurements.
Download or read book Surface and Subsurface Reaction Mechanisms in Atomic Layer Deposition of Metals and Metal Oxides written by Joel Richard Schneider and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology has shown remarkable versatility and strength in response to large-scale challenges facing society today, despite many of its technical applications being on the atomic scale. From renewable energy devices to medical and sequencing technologies, to three-dimensional transistor architectures, advanced water purification, and novel organic-inorganic hybrid materials, nanotechnology has enabled powerful advances through precisely creating materials with specific chemistries and nanostructures. Thin films are particularly robust in their applications, and atomic layer deposition (ALD) is a thin film deposition technique with demonstrated strengths in precision, tunability, and structural control. The core principles of ALD that allow it to achieve these powerful results rely on self-limiting surface chemical reactions; however, despite the prevalence of ALD reports in the literature there are still many surface mechanisms that are poorly understood. ALD material properties can be highly sensitive to process conditions, impurities introduced from surface reactions, subtle changes in reaction rates, and many more phenomena, so it is critical to fully understand the surface reaction mechanisms at play in ALD to effectively implement processes and design chemistries for new materials. Especially as ALD is often idealized to behave in a simple self-limiting manner, the presence of more complex surface reactions that deviate from this behavior necessitates deeper study. As a result, this dissertation presents work to find, characterize, and model new reaction mechanisms in ALD that cause deviations from ideal behavior, then generalize that understanding and apply it to new chemical systems. The first half of the work focuses on activating surface species in the ALD of metal oxides. ALD of iron oxide using ozone is investigated as a case study, and we find that during the process ozone generates reactive oxygen species that migrate below the surface of the growing film where they are stored. The expansion of the ALD reactions beyond the surface of the film to a reservoir of active species in the subsurface region has a host of implications on the ALD process and the resulting material. The storage of reactive species results in high growth rates, and the physical movement of species through the film causes preferential crystalline rearrangement and film roughening. Further studies of nickel oxide ALD found related behaviors, indicating it grows by a similar mechanism of subsurface active species storage. In both cases, the oxygen species are reactive enough to activate surface combustion reactions, including in ALD of other materials grown on top of the reactive reservoirs. These mechanisms are consistent with reports of some other oxides, suggesting oxygen mobility and oxidizability of the metal center may be important factors in facilitating this reservoir mechanism. The second half of this thesis focuses instead on surface passivating species in metal ALD. As ALD hinges on self-limiting reactions resulting from the surface being passivated toward further reaction, the persistence of passivation is key to consistent and precise process function. A promising precursor for ruthenium ALD, Ru(DMBD)(CO)3, is studied due to its unique passivation mechanism of L-type ligands bonded to a zero-oxidation state metal center. Some reports have hypothesized this bonding results in excellent nucleation and growth properties, while others that it results in poor deposition control with better applications in continuous-deposition processes. By studying this ALD process, we can then gain insight into both surface passivation mechanisms and broader principles for process design of metals and zero-oxidation state compounds. We find the precursor undergoes a spontaneous decarbonylation reaction mechanism whereby the surface is initially passivated with carbonyl species that are lost with increasing temperature or time. Comparison of in situ characterization data and first principles kinetic modeling support these findings. Our results help explain inconsistencies in previous reports as well as observations of other zero-oxidation state precursors. Together, characterizing new surface mechanisms in ALD of both activating and passivating species gives a more complete picture of how a range of ALD processes can deviate from idealized and simplified self-limiting surface reactions. These findings span the breadth of both metal and metal oxide ALD, and we apply the insights to new ALD systems involving multicomponent and catalytically activated ALD processes. These grow the chemical toolbox of ALD and illustrate how a proper fundamental chemical understanding of ALD is important not only for effective implementation and control of existing processes but also for generalizing, expanding, and designing tools for ALD to further widen its horizons.
Download or read book Internal Photoemission Spectroscopy written by Valeri V. Afanas'ev and published by Elsevier. This book was released on 2014-02-22 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Internal Photoemission Spectroscopy thoroughly updates this vital, practical guide to internal photoemission (IPE) phenomena and measurements. The book's discussion of fundamental physical and technical aspects of IPE spectroscopic applications is supplemented by an extended overview of recent experimental results in swiftly advancing research fields. These include the development of insulating materials for advanced SiMOS technology, metal gate materials, development of heterostructures based on high-mobility semiconductors, and more. Recent results concerning the band structure of important interfaces in novel materials are covered as well. Internal photoemission involves the physics of charge carrier photoemission from one solid to another, and different spectroscopic applications of this phenomenon to solid state heterojunctions. This technique complements conventional external photoemission spectroscopy by analyzing interfaces separated from the sample surface by a layer of a different solid or liquid. Internal photoemission provides the most straightforward, reliable information regarding the energy spectrum of electron states at interfaces. At the same time, the method enables the analysis of heterostructures relevant to modern micro- and nano-electronic devices as well as new materials involved in their design and fabrication. First complete model description of the internal photoemission phenomena Overview of the most reliable energy barrier determination procedures and trap characterization methods Overview of the most recent results on band structure of high-permittivity insulating materials and their interfaces with semiconductors and metals
Download or read book Oxide Surfaces written by James A. Wingrave and published by CRC Press. This book was released on 2001-07-27 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed treatment of information relating to fluid-oxide interfaces. It outlines methods for quantifying adsorption and desorption of polymeric and non-polymeric solutes at the gas- and solution-oxide interfaces. It also analyzes novel properties of oxide membranes and the synthesis and dissolution of oxide solids.
Download or read book In situ FTIR Study of the Mechanisms of Atomic Layer Deposition of Silicon Oxide written by Luis Fabián Peña-Orduña and published by . This book was released on 2016 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, key aspects of the surface chemistry associated in the atomic layer deposition (ALD) of silicon oxide are discussed. Although atomic layer deposition has become a mature technique that provides a well-controlled, uniform, and conformal film growth, its use for low-temperature deposition of silicon oxides has been challenging, spurring recent efforts to develop silicon precursors and methods to oxidize them appropriately. The main difficulty for making progress is the lack of in-situ chemical characterization, necessary to develop a mechanistic understanding of the process, particularly to understand the growth mechanism of novel precursors. In this work, we have combined in-situ Fourier-transform infrared spectroscopy (FTIR) and density functional theory to investigate the initial surface reaction and growth mechanism of SiO2 thin films by atomic layer deposition using two recently developed aminosilanes, di-sec-butylaminosilane (DSBAS) and bis(t-butylamino)silane (BTBAS), as silicon sources and ozone as oxygen source. This work provides the first direct insight into both the initial adsorption of DSBAS and BTBAS molecules on OH terminated oxidized Si(100) surfaces, and the subsequent ALD processes, and underscores the dependence of the process on the flow rate of ozone.
