Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Bulk Gallium Nitride Overgrowth By Hydride Vapour Phase Epitaxy On Compliant Nano Column Substrates
Download Bulk Gallium Nitride Overgrowth By Hydride Vapour Phase Epitaxy On Compliant Nano Column Substrates full books in PDF, epub, and Kindle. Read online Bulk Gallium Nitride Overgrowth By Hydride Vapour Phase Epitaxy On Compliant Nano Column Substrates ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Bulk Gallium Nitride Overgrowth by Hydride Vapour Phase Epitaxy on Compliant Nano-column Substrates by : Alan Paul Gott
Download or read book Bulk Gallium Nitride Overgrowth by Hydride Vapour Phase Epitaxy on Compliant Nano-column Substrates written by Alan Paul Gott and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Hydride vapour phase epitaxy growth, crystal properties and dopant incorporation in gallium nitride by : Patrick Hofmann
Download or read book Hydride vapour phase epitaxy growth, crystal properties and dopant incorporation in gallium nitride written by Patrick Hofmann and published by BoD – Books on Demand. This book was released on 2018-08-15 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation employs doping to investigate basic gallium nitride (GaN) crystal properties and to solve challenges of the hydride vapour phase epitaxy (HVPE) growth process. Whereas the first chapter is a short introduction to the history of the GaN single crystal growth, the 2nd chapter introduces to current crystal growth techniques, discusses properties of the GaN material system and the resulting influence on the applicable crystal growth techniques. HVPE, as a vapour phase epitaxy crystal growth method will be explained in greater detail, with focus on the used vertical reactor and its capabilities for doping. The 3rd chapter then focusses on point defects in GaN, specifically on intentionally introduced extrinsic point defects used for doping purposes, i.e. to achieve p-type, n-type or semi-insulating behaviour. Different dopants will be reviewed before the diffusion of point defects in a solid will be discussed. The in-situ introduction of iron, manganese, and carbon during crystal growth is employed in chapter 4 to compensate the unintentional doping (UID) of the GaN crystals, and therefore to achieve truly semi-insulating behaviour of the HVPE GaN. However the focus of this chapter lies on the characterisation of the pyroelectric coefficient (p), as semi-insulating properties are a necessary requirement for the applied Sharp-Garn measurement method. The creation of tensile stress due to in-situ silicon doping during GaN crystal growth is the topic of the 5th chapter. The tensile stress generation effect will be reproduced and the strain inside the crystal will be monitored ex-situ employing Raman spectroscopy. The n-type doping is achieved by using a vapour phase doping line and a process is developed to hinder the tensile strain generation effect. The 6th chapter concentrates on the delivery of the doping precursor via a solid state doping line, a newly developed doping method. Similar to chapter 5, the doping line is characterised carefully before the germanium doping is employed to the GaN growth. The focus lies on the homogeneity of the germanium doping and it is compared compared to the silicon doping and the vapour phase doping line. Benefits and drawbacks are discussed in conjunction with the obtained results. The germanium doping via solid state doping line is applied to the HVPE GaN growth process to measure accurately growth process related properties unique to the applied set of GaN growth parameters.
Book Synopsis Formation of Gallium Nitride Templates and Freestanding Substrates by Hydride Vapor Phase Epitaxy for Homoepitaxial Growth of III-nitride Devices by : Adrian Daniel Williams
Download or read book Formation of Gallium Nitride Templates and Freestanding Substrates by Hydride Vapor Phase Epitaxy for Homoepitaxial Growth of III-nitride Devices written by Adrian Daniel Williams and published by . This book was released on 2007 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The GaN samples grown for this dissertation were studied by various techniques to characterize their structural, optical, and electrical properties.
Book Synopsis Gallium Nitride Epitaxy by a Novel Hybrid VPE Technique by : David J. Miller
Download or read book Gallium Nitride Epitaxy by a Novel Hybrid VPE Technique written by David J. Miller and published by Stanford University. This book was released on 2011 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium nitride is an important material for the production of next-generation visible and near-UV optical devices, as well as for high temperature electronic amplifiers and circuits; however there has been no bulk method for the production of GaN substrates for device layer growth. Instead, thick GaN layers are heteroepitaxially deposited onto non-native substrates (usually sapphire) by one of two vapor phase epitaxy (VPE) techniques: MOVPE (metalorganic VPE) or HVPE (hydride VPE). Each method has its strengths and weaknesses: MOVPE has precise growth rate and layer thickness control but it is slow and expensive; HVPE is a low-cost method for high rate deposition of thick GaN, but it lacks the precise control and heterojunction layer growth required for device structures. Because of the large (14%) lattice mismatch, GaN grown on sapphire requires the prior deposition of a low temperature MOVPE nucleation layer using a second growth process in a separate deposition system. Here we present a novel hybrid VPE system incorporating elements of both techniques, allowing MOVPE and HVPE in a single growth run. In this way, a thick GaN layer can be produced directly on sapphire. GaN growth commences as small (50-100 nm diameter) coherent strained 3-dimensional islands which coalesce into a continuous film, after which 2-dimensional layer growth commences. The coalescence of islands imparts significant stress into the growing film, which increases with the film thickness until catastrophic breakage occurs, in-situ. Additionally, the mismatch in thermal expansion rates induces compressive stress upon cooling from the growth temperature of 1025°C. We demonstrate a growth technique that mitigates these stresses, by using a 2-step growth sequence: an initial high growth rate step resulting in a pitted but relaxed film, followed by a low growth rate smoothing layer. As a result, thick (> 50 [Mu]m) and freestanding films have been grown successfully. X-ray rocking curve linewidth of 105 arcseconds and 10K PL indicating no "yellow" emission indicate that the material quality is higher than that produced by conventional MOVPE. By further modifying the hybrid system to include a metallic Mn source, it is possible to grow a doped semi-insulating GaN template for use in high frequency electronics devices.
Book Synopsis Characterization of Hydride Vapor Phase Epitaxy Grown GaN Substrates for Future III-nitride Growth by : Alaa Ahmad Kawagy
Download or read book Characterization of Hydride Vapor Phase Epitaxy Grown GaN Substrates for Future III-nitride Growth written by Alaa Ahmad Kawagy and published by . This book was released on 2019 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this research is to investigate and characterize the quality of commercially obtained gallium nitride (GaN) on sapphire substrates that have been grown using hydride vapor phase epitaxy (HVPE). GaN substrates are the best choice for optoelectronic applications because of their physical and electrical properties. Even though HVPE GaN substrates are available at low-cost and create the opportunities for growth and production, these substrates suffer from large macro-scale defects on the surface of the substrate. In this research, four GaN on sapphire substrates were investigated in order to characterize the surface defects and, subsequently, understand their influence on homoepitaxial GaN growth. Two substrates were unintentionally doped (UID) GaN on sapphire, and the other two were semi-insulating (SI) GaN on sapphire which were doped with iron (Fe) in order to compensate the background doping inherent in GaN. Several characterization techniques were performed. Atomic force microscopy, scanning electron microscopy, and optical microscopy were performed to characterize the surface morphology. X-ray diffraction, cathodoluminescence, transmission measurements, and optical transmission electron microscopy were applied to study the bulk structural and optical properties. The investigation of the surface of GaN substrates exposed various defects that are associated with defects in the structure such as dislocations, as well as vacancies and point defects. The UID GaN substrates suffered from hexagonal V-shape pits with pits densities of approximately 107 and 108 cm-2, whereas, the SI GaN substrates exhibited much larger macro-scale pits with areal densities of about 102 cm-2. X-ray diffraction results were deconvoluted in order to characterize the screw and mixed (edge and screw) dislocation densities for the studied substrates. The UID substrates exhibited screw dislocation densities of 107 and 108 cm-2 and mixed dislocation densities of 109 and 1010 cm-2. The SI substrates, however, exhibit generally lower densities of dislocations of 109 and 108 cm-2 for screw and mixed, respectively. Cathodoluminescence measurements demonstrated interesting results for the UID and SI substrates with energies of 4 and 3.5 eV, respectively. The transmission measurements for the UID substrates showed that the bandgap energy was 3.39 eV.
Book Synopsis Growth and Characterization of Free-standing Gallium Nitride Substrates by the Hydride-metalorganic Vapor Phase Epitaxy Technique by : Michael D. Reed
Download or read book Growth and Characterization of Free-standing Gallium Nitride Substrates by the Hydride-metalorganic Vapor Phase Epitaxy Technique written by Michael D. Reed and published by . This book was released on 2002 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Gallium Nitride Epitaxy by a Novel Hybrid VPE Technique by : David J. Miller
Download or read book Gallium Nitride Epitaxy by a Novel Hybrid VPE Technique written by David J. Miller and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium nitride is an important material for the production of next-generation visible and near-UV optical devices, as well as for high temperature electronic amplifiers and circuits; however there has been no bulk method for the production of GaN substrates for device layer growth. Instead, thick GaN layers are heteroepitaxially deposited onto non-native substrates (usually sapphire) by one of two vapor phase epitaxy (VPE) techniques: MOVPE (metalorganic VPE) or HVPE (hydride VPE). Each method has its strengths and weaknesses: MOVPE has precise growth rate and layer thickness control but it is slow and expensive; HVPE is a low-cost method for high rate deposition of thick GaN, but it lacks the precise control and heterojunction layer growth required for device structures. Because of the large (14%) lattice mismatch, GaN grown on sapphire requires the prior deposition of a low temperature MOVPE nucleation layer using a second growth process in a separate deposition system. Here we present a novel hybrid VPE system incorporating elements of both techniques, allowing MOVPE and HVPE in a single growth run. In this way, a thick GaN layer can be produced directly on sapphire. GaN growth commences as small (50-100 nm diameter) coherent strained 3-dimensional islands which coalesce into a continuous film, after which 2-dimensional layer growth commences. The coalescence of islands imparts significant stress into the growing film, which increases with the film thickness until catastrophic breakage occurs, in-situ. Additionally, the mismatch in thermal expansion rates induces compressive stress upon cooling from the growth temperature of 1025°C. We demonstrate a growth technique that mitigates these stresses, by using a 2-step growth sequence: an initial high growth rate step resulting in a pitted but relaxed film, followed by a low growth rate smoothing layer. As a result, thick (> 50 [Mu]m) and freestanding films have been grown successfully. X-ray rocking curve linewidth of 105 arcseconds and 10K PL indicating no "yellow" emission indicate that the material quality is higher than that produced by conventional MOVPE. By further modifying the hybrid system to include a metallic Mn source, it is possible to grow a doped semi-insulating GaN template for use in high frequency electronics devices.
Book Synopsis Development of Non-polar, A-plane Gallium Nitride Templates by Hydride Vapor Phase Epitaxy by : Adam Lyle Moldawer
Download or read book Development of Non-polar, A-plane Gallium Nitride Templates by Hydride Vapor Phase Epitaxy written by Adam Lyle Moldawer and published by . This book was released on 2008 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Growth of Gallium Nitride and Indium Nitride Films and Nanostructured Materials by Hydride-metalorganic Vapor Phase Epitaxy by : Hyun Jong Park
Download or read book Growth of Gallium Nitride and Indium Nitride Films and Nanostructured Materials by Hydride-metalorganic Vapor Phase Epitaxy written by Hyun Jong Park and published by . This book was released on 2006 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crack-free, 3 mum GaN films were grown on GaN/AlGaN/Si template at 850°C although cracks developed when the thickness exceeded 7 mum. It was possible, however, to grow crack-free polycrystalline 40 mum thick GaN on Si using InN NRs as a buffer material.
Book Synopsis Structure of Nonpolar Gallium Nitride Films Grown by Hydride Vapor Phase Epitaxy by : Benjamin Allen Haskell
Download or read book Structure of Nonpolar Gallium Nitride Films Grown by Hydride Vapor Phase Epitaxy written by Benjamin Allen Haskell and published by . This book was released on 2005 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conventional c-plane (Al, In, Ga)N optoelectronic devices suffer from deleterious polarization effects. These polarization effects can be eliminated by growing devices on alternative orientations of GaN crystals, such as {11 ̄00} m-plane or {112 ̄0} a-plane films. Previous attempts to grow nonpolar GaN by HVPE, yielded rough and faceted surfaces that were unsuitable for substrate use.
Book Synopsis Characterization of Doped Gallium Substrates by : Jack Lee Owsley (III)
Download or read book Characterization of Doped Gallium Substrates written by Jack Lee Owsley (III) and published by . This book was released on 2012 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis the characteristics of five bulk semi-insulated doped gallium nitride samples provided by Kyma Technologies, Inc were explored. The five GaN samples were grown on sapphire substrates by hydride vapor phase epitaxy (HVPE) and doped with different concentrations of iron, hydrogen, carbon, oxygen and silicon. The first step of characterization was measuring the optical absorption of all the samples using a UV-NIR fiber spectrometer. Through this procedure it was found that they all showed a strong absorption at 518 nm. Thus, time-resolved differential transmission measurements were conducted at this wavelength using the second harmonic generation (SHG) of a femtosecond ytterbium-doped fiber amplifier (YDFA), mode-locked laser. Relaxation times between 24 and 433 picoseconds were obtained. Finally, four point probe measurements were performed in the order to determine the bulk resistivity of the GaN samples. The measured values are within the order of 106[omega]*m for all samples.
Book Synopsis System for Bulk Growth of Gallium Nitride. Vapor Phase Epitaxy of Gallium Nitride by Gallium Arc Evaporation by :
Download or read book System for Bulk Growth of Gallium Nitride. Vapor Phase Epitaxy of Gallium Nitride by Gallium Arc Evaporation written by and published by . This book was released on 2005 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: A vapor phase growth system intended for the growth of bulk gallium nitride crystals was investigated. Potential advantages of the growth technique are cheap source materials of high purity, no corrosive gasses, and low operating and equipment costs. Ga contained in a crucible was evaporated by an arc discharge between a W-electrode and the Ga surface, and was transported to the growth zone by a carrier gas flowing over the Ga source. After mixing with ammonia, the mixture was passed between a top and a bottom susceptor, on which samples were mounted. High growth rates as high as 30 micrometers/hr were obtained on the top sample. The surface of deposited material was rough near the front of the susceptor, but was specular elsewhere and showed step-flow growth morphology in atomic force microscopy. The bottom sample experienced lower growth rates and a high density of macroscopic defects, presumably caused by Ga droplets in the gas phase. Computer flow dynamic simulations predicted growth rates 4 times higher than experiments. The discrepancy was attributed to ammonia pre-reactions, based on the experimental growth rate dependence on ammonia partial pressure. An additional factor 4 reduction in efficiency was due to Ga wall condensation between the evaporation and growth zones. The overall growth efficiency was 2 %.
Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2002 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Growth of GaN by Hydride Vapor Phase Epitaxy by : Volker Wagner
Download or read book Growth of GaN by Hydride Vapor Phase Epitaxy written by Volker Wagner and published by . This book was released on 2001 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Hydride Vapor Phase Epitaxy of GaN on Silicon Covered by Nanostructures by :
Download or read book The Hydride Vapor Phase Epitaxy of GaN on Silicon Covered by Nanostructures written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards by :
Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 2008 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Optoelectronic Devices by : M Razeghi
Download or read book Optoelectronic Devices written by M Razeghi and published by Elsevier. This book was released on 2004 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tremendous progress has been made in the last few years in the growth, doping and processing technologies of the wide bandgap semiconductors. As a result, this class of materials now holds significant promis for semiconductor electronics in a broad range of applications. The principal driver for the current revival of interest in III-V Nitrides is their potential use in high power, high temperature, high frequency and optical devices resistant to radiation damage. This book provides a wide number of optoelectronic applications of III-V nitrides and covers the entire process from growth to devices and applications making it essential reading for those working in the semiconductors or microelectronics. Broad review of optoelectronic applications of III-V nitrides
