Download or read book Study of Metal Contacts to Gallium face and Nitrogen face N type GaN Material written by Di Zhu and published by . This book was released on 2008 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Contacts to P type Gallium Nitride written by Sujit Pillai and published by . This book was released on 1999 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gallium Nitride Processing for Electronics Sensors and Spintronics written by Stephen J. Pearton and published by Springer Science & Business Media. This book was released on 2006-02-24 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor spintronics is expected to lead to a new generation of transistors, lasers and integrated magnetic sensors that can be used to create ultra-low power, high speed memory, logic and photonic devices. Useful spintronic devices will need materials with practical magnetic ordering temperatures and current research points to gallium and aluminium nitride magnetic superconductors as having great potential. This book details current research into the properties of III-nitride semiconductors and their usefulness in novel devices such as spin-polarized light emitters, spin field effect transistors, integrated sensors and high temperature electronics. Written by three leading researchers in nitride semiconductors, the book provides an excellent introduction to gallium nitride technology and will be of interest to all reseachers and industrial practitioners wishing to keep up to date with developments that may lead to the next generation of transistors, lasers and integrated magnetic sensors.

Download or read book Some Experimental Studies of N Type Gan and Au Gan Contacts written by Ke Wang and published by . This book was released on 2017-01-28 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Some experimental studies of n-type GaN and Au/GaN contacts" by Ke, Wang, 王科, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled SOME EXPERIMENTAL STUDIES OF N-TYPE GaN AND Au/GaN CONTACTS Submitted by Wang Ke for the degree of Master of Philosophy at The University of Hong Kong in December 2002 Schottky and ohmic contacts made on both undoped n-type HVPE (Hydride Vapour Phase Epitaxy) and MBE (Molecular Beam Epitaxy) grown GaN epilayers with similar nominal carrier-concentration levels were studied. Close to ideal Au- GaN Schottky junctions together with low resistance Al and In ohmic contacts were obtained when using the HVPE material. For the MBE material, however, under identical fabrication procedures the electrical characteristics of both Schottky and ohmic contacts were poor. The result was correlated with the material quality of the epilayers observed by photoluminescence spectroscopy, Hall measurement and atomic-force microscopy, which showed that the concentrations of point defects and dislocations were significantly higher in the MBE grown material. It is suggested that point defects or impurity-related defects lead to Schottky contact degradation and the observed increase in ohmic contact resistance. These results show the importance of material quality when making contacts on GaN epilayers and suggest that the intensity of the band-to-band photoluminescence signal is a suitable parameter for assessing the material quality prior to metalization. The electrical characteristics of Au/n-GaN Schottky contacts with different Au film thickness up to 1300A were investigated using current-voltage (I-V) and capacitance-voltage (C-V) techniques. The results showed a steady decrease in the quality of the Schottky diodes for increasing Au-film thickness. The I-V measurements indicated that thin (500 A). Schottky barrier heights obtained by C-V analysis were 0.1-0.2eV greater than those found from the I-V measurements, indicating that current transport through the barrier is not purely thermionic. Ideality factors of 2 confirmed this. Both Schottky barrier height and reverse breakdown bias were found to decrease with increasing Au thickness. Depth profiling Auger Electron Spectroscopy (AES) showed that the Au/GaN junction interface width increased with increasing Au thickness, and suggesting considerable inter-mixing of Au, Ga and N. The results were interpreted in terms of Ga out-diffusion from the GaN giving rise to gallium vacancies that in turn acted as sites for electron-hole pair generation within the depletion region. The study supports the recent suggestion that gallium vacancies associated with threaded dislocations play an important role in junction breakdown. DOI: 10.5353/th_b2666361 Subjects: Gallium nitride Ohmic contacts Diodes, Schottky-barrier

Download or read book Development and Characterization of Ohmic and Schottky Contacts for Gallium Nitride and Aluminum Gallium Nitride Devices written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book GaN and Related Materials written by Stephen J. Pearton and published by CRC Press. This book was released on 2021-10-08 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents views on current developments in heat and mass transfer research related to the modern development of heat exchangers. Devotes special attention to the different modes of heat and mass transfer mechanisms in relation to the new development of heat exchangers design. Dedicates particular attention to the future needs and demands for further development in heat and mass transfer. GaN and related materials are attracting tremendous interest for their applications to high-density optical data storage, blue/green diode lasers and LEDs, high-temperature electronics for high-power microwave applications, electronics for aerospace and automobiles, and stable passivation films for semiconductors. In addition, there is great scientific interest in the nitrides, because they appear to form the first semiconductor system in which extended defects do not severely affect the optical properties of devices. This series provides a forum for the latest research in this rapidly-changing field, offering readers a basic understanding of new developments in recent research. Series volumes feature a balance between original theoretical and experimental research in basic physics, device physics, novel materials and quantum structures, processing, and systems.

Download or read book An Analysis of Metal Contacts to GaN written by William Patrick Lewis and published by . This book was released on 2007 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ohmic and Schottky contacts to GaN on sapphire and free standing GaN are investigated. A detailed analysis of the circular Transmission Line Mea-surement (c-TLM) technique is carried out. We show the need to accurately measure the contact radii to extract accurate contact resistivity values, _c using c-TLM, for contacts to p-type GaN. Small measurement errors, _ 0.5 _m, lead to large errors in _c, especially as _c decreases. An alternative technique to extract _c, based on the series resistance of a p-n diode, is investigated. This method relies on uniform current density over the whole metal{semiconductor diode contact and the existence of a singular diode ideality. Defects in p-type GaN on LED material are shown to electroplate preferentially. Ni plated defects annealed in an O2 atmosphere are shown to be passivated, with signi_cant measured improvements in the I{V and L{I char- acteristics of LEDs. Electroless deposition is explored as an alternative contact formation technique. This novel approach yields Ni/Au, p-type ohmic contacts, with a _c comparable with evaporated contacts. A _c of 2.2 x 10_2 cm_2 at room temperature and a _c of 2.5 x 10_2 cm_2 at 410 K indicate the tunneling nature of the contact. The method provides for a reduction in the cost and processing time associated with ohmic contact formation. CoW contacts to n-type GaN are shown to be rectifying even after a 6500C anneal. KOH etching of Ga-face, freestanding, n-type, GaN, is shown to aid ohmic contact formation and remove the need for a high temperature anneal. Schottky contacts were optimised on low doped epi-layers, on free standing n-GaN substrates. The contacts are governed by thermionic emission, with low ideality, 1.04 and low on-state resistance, 0.57 mcm2. The idealities of the devices are shown to decrease with increasing temperature, while the barrier heights remain relatively constant. KOH treatments of the material were shown to increase the Schottky barrier height and reduce reverse leakage currents.

Download or read book Gallium Nitride and Related Materials written by and published by . This book was released on 1997 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Contacts on ZnSe and GaN written by Kristen Joy Duxstad and published by . This book was released on 1997 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Study of Aluminum Gallium Nitride gallium Nitride Polarization Barriers Aluminum Gallium Nitride silicon Carbide Heterojunction Bipolar Transistors and Polarization based Ohmic Contacts written by Choudhury Jayant Praharaj and published by . This book was released on 2004 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermally Stable Ohmic and Schottky Contacts to GaN written by Lars Fredrik Voss and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: This dissertation is focused on the development of Ohmic and Schottky contacts to both nand p-type Gallium Nitride for use in microelectronic and optical devices. The goal is to develop low resistance contacts with greater thermal budgets and superior thermal aging characteristics to those commonly in use today as well as to understand the mechanisms by which these contacts may fail. In addition, p-type Ohmic contacts have been used to fabricate light emitting diodes (LEDs) which display far superior aging properties than those made with conventional Ni/Au contacts. Ohmic contacts to p-GaN were fabricated using a variety of refractory materials. The materials examined were of three basic types: boride, nitride, and the refractory metal Ir. The boride family includes W2B, W2B5, CrB2, ZrB2, and TiB2. The nitrides examined were TaN, TiN, and ZrN. Contacts based on these materials were fabricated using either a GaN//Ni/Au/X/Ti/Au, GaN//X/Ti/Au, or GaN//Ni/X/Au scheme, where X is the refractory material. Contact resistances as low as ~1 x 10-4 ohm/cm2 were consistently achieved after annealing at temperatures from 500-1000°C for 60 s in N2 using these materials for p-GaN with a carrier concentration of ~1 x 1017 cm-3.

Download or read book Studies on Pt Ru and Pd Ru Schottky Contacts to N type Gallium Nitride written by N. Nanda Kumar Reddy and published by . This book was released on 2016-11-05 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ohmic Contacts to the Wide Band Gap Semiconductor Gallium Nitride and to Aluminum Gallium Nitride gallium Nitride Heterostructures written by Michael Lee Schuette and published by . This book was released on 2005 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: To meet temperature and process latitude requirements for ohmic contacts to n-GaN and to AlGaN/GaN heterostructures, a low-temperature copper germanide ohmic contact with a wide processing window was designed and applied to moderately-doped n-GaN achieving [rho]c = 1.1 x 10−5 [omega] cm2 (and Rc x W = 0.26 [omega] mm) and AlGaN/GaN heterostructures achieving [rho]c = 1.6 x 10−4 [omega] cm2 (and Rc X W = 3.6 [omega] mm). It was determined that SiCl4 RIE at low self-bias smooths the n-GaN surface while at high bias the roughness increases only slightly. Core level analysis showed that ion bombardment of n-GaN reduced surface oxidation and increased the concentration of N vacancies at the surface, both of which correlated well with [rho]c's measured via I-V. Auger depth profiling showed that after annealing, both N and Ga diffused out of the GaN and Ge and Cu diffused in. The change in Ge in-diffusion due to annealing, when compared to the as-deposited contact, was greater than that of Cu. The Auger and X-ray photoemission data support the assertion that the ohmic behavior of the copper germanide ohmic contact on n-GaN is due to electron tunneling, which is enhanced by a heavily doped interfacial region created by VN and Ge on VGa, both of which serve as donors in n-GaN. The physical mechanism which provides ohmic contact to AlGaN/GaN heterostructure is similar to that of the n-GaN case with respect to the contamination removal, nitrogen vacancy creation, and germanium occupation of gallium vacancies. However, it is important that the AlGaN layer not be etched such that the source of carriers from this layer for use in the 2DEG channel is depleted. Comments addressing future work that should be done to improve this contact system and allow its use for self-aligned high-electron mobility transistors (HEMTs) are made.

Download or read book Power GaN Devices written by Matteo Meneghini and published by Springer. This book was released on 2016-09-08 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the first comprehensive overview of the properties and fabrication methods of GaN-based power transistors, with contributions from the most active research groups in the field. It describes how gallium nitride has emerged as an excellent material for the fabrication of power transistors; thanks to the high energy gap, high breakdown field, and saturation velocity of GaN, these devices can reach breakdown voltages beyond the kV range, and very high switching frequencies, thus being suitable for application in power conversion systems. Based on GaN, switching-mode power converters with efficiency in excess of 99 % have been already demonstrated, thus clearing the way for massive adoption of GaN transistors in the power conversion market. This is expected to have important advantages at both the environmental and economic level, since power conversion losses account for 10 % of global electricity consumption. The first part of the book describes the properties and advantages of gallium nitride compared to conventional semiconductor materials. The second part of the book describes the techniques used for device fabrication, and the methods for GaN-on-Silicon mass production. Specific attention is paid to the three most advanced device structures: lateral transistors, vertical power devices, and nanowire-based HEMTs. Other relevant topics covered by the book are the strategies for normally-off operation, and the problems related to device reliability. The last chapter reviews the switching characteristics of GaN HEMTs based on a systems level approach. This book is a unique reference for people working in the materials, device and power electronics fields; it provides interdisciplinary information on material growth, device fabrication, reliability issues and circuit-level switching investigation.

Download or read book The Journal of the Korean Physical Society written by and published by . This book was released on 2006 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book GaN and Related Materials II written by Stephen J. Pearton and published by CRC Press. This book was released on 2000-10-31 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first GaN and Related Materials covered topics such as a historical survey of past research, optical electrical and microstructural characterization, theory of defects, bulk crystal growth, and performance of electronic and photonic devices. This new volume updates old research where warranted and explores new areas such as UV detectors, microwave electronics, and Er-doping. This unique follow-up features contributions from leading experts that cover the full spectrum of growth.

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt: