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Fabrication And Characterization Of Gan Based Semiconductor Devices For High Frequency And High Power Applications
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Book Synopsis Fabrication and Characterization of GaN-based Semiconductor Devices for High Frequency and High Power Applications by : 張家達
Download or read book Fabrication and Characterization of GaN-based Semiconductor Devices for High Frequency and High Power Applications written by 張家達 and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fabrication and Characterization of GaN-based Semiconductor Devices for High-Power and Microwave Power Applications by :
Download or read book Fabrication and Characterization of GaN-based Semiconductor Devices for High-Power and Microwave Power Applications written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Fabrication and Characterization of GaN-based Semiconductor Devices on Si Substrates for High-Power Electronic Applications by :
Download or read book Fabrication and Characterization of GaN-based Semiconductor Devices on Si Substrates for High-Power Electronic Applications written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Gan-based Materials And Devices: Growth, Fabrication, Characterization And Performance by : Robert F Davis
Download or read book Gan-based Materials And Devices: Growth, Fabrication, Characterization And Performance written by Robert F Davis and published by World Scientific. This book was released on 2004-05-07 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique materials properties of GaN-based semiconductors have stimulated a great deal of interest in research and development regarding nitride materials growth and optoelectronic and nitride-based electronic devices. High electron mobility and saturation velocity, high sheet carrier concentration at heterojunction interfaces, high breakdown field, and low thermal impedance of GaN-based films grown over SiC or bulk AlN substrates make nitride-based electronic devices very promising. The chemical inertness of nitrides is another key property.This volume, written by experts on different aspects of nitride technology, addresses the entire spectrum of issues related to nitride materials and devices, and it will be useful for technologists, scientists, engineers, and graduate students who are working on wide bandgap materials and devices. The book can also be used as a supplementary text for graduate courses on wide bandgap semiconductor technology.
Book Synopsis Wide Bandgap Based Devices by : Farid Medjdoub
Download or read book Wide Bandgap Based Devices written by Farid Medjdoub and published by MDPI. This book was released on 2021-05-26 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emerging wide bandgap (WBG) semiconductors hold the potential to advance the global industry in the same way that, more than 50 years ago, the invention of the silicon (Si) chip enabled the modern computer era. SiC- and GaN-based devices are starting to become more commercially available. Smaller, faster, and more efficient than their counterpart Si-based components, these WBG devices also offer greater expected reliability in tougher operating conditions. Furthermore, in this frame, a new class of microelectronic-grade semiconducting materials that have an even larger bandgap than the previously established wide bandgap semiconductors, such as GaN and SiC, have been created, and are thus referred to as “ultra-wide bandgap” materials. These materials, which include AlGaN, AlN, diamond, Ga2O3, and BN, offer theoretically superior properties, including a higher critical breakdown field, higher temperature operation, and potentially higher radiation tolerance. These attributes, in turn, make it possible to use revolutionary new devices for extreme environments, such as high-efficiency power transistors, because of the improved Baliga figure of merit, ultra-high voltage pulsed power switches, high-efficiency UV-LEDs, and electronics. This Special Issue aims to collect high quality research papers, short communications, and review articles that focus on wide bandgap device design, fabrication, and advanced characterization. The Special Issue will also publish selected papers from the 43rd Workshop on Compound Semiconductor Devices and Integrated Circuits, held in France (WOCSDICE 2019), which brings together scientists and engineers working in the area of III–V, and other compound semiconductor devices and integrated circuits. In particular, the following topics are addressed: – GaN- and SiC-based devices for power and optoelectronic applications – Ga2O3 substrate development, and Ga2O3 thin film growth, doping, and devices – AlN-based emerging material and devices – BN epitaxial growth, characterization, and devices
Book Synopsis Design, Fabrication and Characterization of GaN-based Devices for Power Applications by : Burcu Ercan
Download or read book Design, Fabrication and Characterization of GaN-based Devices for Power Applications written by Burcu Ercan and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium Nitride (GaN) and related alloys have gained considerable momentum in recent years since the improvement in silicon (Si) based power devices is now only incremental. GaN is a promising material for high-power, high-frequency applications due to its wide bandgap, high carrier mobility which result in devices with high breakdown voltage, low on-resistance, and high temperature stability. Despite the superior properties of GaN there is still room for improvement in device design and fabrication to reach theoretical limits of GaN based devices. Reaching the theoretical critical electric field in GaN devices has been challenging due to the presence of threading dislocations, surface impurities introduced during material growth and fabrication process. In order to prevent premature breakdown of the devices, these defects must be mitigated. In this study, avalanche breakdown was observed in p-n diodes fabricated with low power reactive ion etch with a moat etch profile, followed by Mg ion implantation to passivate the plasma damages. Additionally, the devices were fabricated on free standing GaN substrates which has lower dislocation than sapphire or SiC substrates. The electron and hole impact ionization coefficients were extracted separately by analyzing the ultraviolet (UV) assisted reverse bias current voltage measurements of vertical p-n and n-p diodes. GaN and related alloy such as Indium Aluminum Nitride (InAlN) or Aluminum Gallium Nitride (AlGaN) form a high mobility, high density sheet charge at the heterojunction. High electron mobility transistor (HEMT) devices fabricated on these layer stacks are depletion mode (normally-on) devices with a negative threshold voltage. However, normally-on devices are not preferred in power applications due to safety reasons and to reduce the external circuitry. Therefore, the development of an enhancement mode (normally-off) GaN based high electron mobility transistors (HEMT) with positive threshold voltage is important for next generation power devices. Several methods, such as growing a p-GaN on the barrier layer, recessed gate by dry etching, plasma treatment under the gate have been previously studied to develop enhancement-mode HEMT devices. In this study, MOS-HEMT devices were fabricated by selective thermal oxidation of InAlN to reduce InAlN barrier thickness under the gate contact. The thermal oxidation of InAlN occurs at temperatures above 600°C, while GaN oxidation occurs above 1000°C at a slow rate which allows the decrease of the InAlN barrier layer thickness under the gate in a reliable way due to the self-limiting nature of oxidation. A positive shift in the threshold voltage and a reduction in reverse leakage current was demonstrated on MOS-diode structures by thermally oxidizing InAlN layers with In composition of 0.17, 0.178 and 0.255 for increasing oxidation durations at 700°C and 800°C. Enhancement mode device operation was demonstrated on lattice matched InAlN/AlN/GaN/Sapphire MOS-HEMT devices by selective thermal oxidation of InAlN layer under the gate contact. A positive threshold voltage was observed for devices which were subjected to thermal oxidation at 700°C for 10, 30 and 60 minutes. The highest threshold voltage was observed as 1.16 V for the device that was oxidized for 30 minutes at 700°C. The maximum transconductance and the maximum drain saturation current of this device was 4.27 mS/mm and 150 mA/mm, respectively.
Book Synopsis Power GaN Devices by : Matteo Meneghini
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.
Book Synopsis Gallium Nitride (GaN) by : Farid Medjdoub
Download or read book Gallium Nitride (GaN) written by Farid Medjdoub and published by CRC Press. This book was released on 2017-12-19 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addresses a Growing Need for High-Power and High-Frequency Transistors Gallium Nitride (GaN): Physics, Devices, and Technology offers a balanced perspective on the state of the art in gallium nitride technology. A semiconductor commonly used in bright light-emitting diodes, GaN can serve as a great alternative to existing devices used in microelectronics. It has a wide band gap and high electron mobility that gives it special properties for applications in optoelectronic, high-power, and high-frequency devices, and because of its high off-state breakdown strength combined with excellent on-state channel conductivity, GaN is an ideal candidate for switching power transistors. Explores Recent Progress in High-Frequency GaN Technology Written by a panel of academic and industry experts from around the globe, this book reviews the advantages of GaN-based material systems suitable for high-frequency, high-power applications. It provides an overview of the semiconductor environment, outlines the fundamental device physics of GaN, and describes GaN materials and device structures that are needed for the next stage of microelectronics and optoelectronics. The book details the development of radio frequency (RF) semiconductor devices and circuits, considers the current challenges that the industry now faces, and examines future trends. In addition, the authors: Propose a design in which multiple LED stacks can be connected in a series using interband tunnel junction (TJ) interconnects Examine GaN technology while in its early stages of high-volume deployment in commercial and military products Consider the potential use of both sunlight and hydrogen as promising and prominent energy sources for this technology Introduce two unique methods, PEC oxidation and vapor cooling condensation methods, for the deposition of high-quality oxide layers A single-source reference for students and professionals, Gallium Nitride (GaN): Physics, Devices, and Technology provides an overall assessment of the semiconductor environment, discusses the potential use of GaN-based technology for RF semiconductor devices, and highlights the current and emerging applications of GaN.
Book Synopsis High-Frequency GaN Electronic Devices by : Patrick Fay
Download or read book High-Frequency GaN Electronic Devices written by Patrick Fay and published by Springer. This book was released on 2019-08-01 with total page 309 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together recent research by scientists and device engineers working on both aggressively-scaled conventional transistors as well as unconventional high-frequency device concepts in the III-N material system. Device concepts for mm-wave to THz operation based on deeply-scaled HEMTs, as well as distributed device designs based on plasma-wave propagation in polarization-induced 2DEG channels, tunneling, and hot-carrier injection are discussed in detail. In addition, advances in the underlying materials science that enable these demonstrations, and advancements in metrology that permit the accurate characterization and evaluation of these emerging device concepts are also included. Targeting readers looking to push the envelope in GaN-based electronics device research, this book provides a current, comprehensive treatment of device concepts and physical phenomenology suitable for applying GaN and related materials to emerging ultra-high-frequency applications. Offers readers an integrated treatment of the state of the art in both conventional (i.e., HEMT) scaling as well as unconventional device architectures suitable for amplification and signal generation in the mm-wave and THz regime using GaN-based devices, written by authors that are active and widely-known experts in the field; Discusses both conventional scaled HEMTs (into the deep mm-wave) as well as unconventional approaches to address the mm-wave and THz regimes; Provides “vertically integrated” coverage, including materials science that enables these recent advances, as well as device physics & design, and metrology techniques; Includes fundamental physics, as well as numerical simulations and experimental realizations.
Book Synopsis Fabrication and Characterization of GaN-based High-Electron-Mobility Transistors for High-Frequency Applications by :
Download or read book Fabrication and Characterization of GaN-based High-Electron-Mobility Transistors for High-Frequency Applications written by and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis GaN Technology by : Maurizio Di Paolo Emilio
Download or read book GaN Technology written by Maurizio Di Paolo Emilio and published by Springer Nature. This book was released on with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Nanoelectronic Devices and Applications by : Trupti Ranjan Lenka
Download or read book Nanoelectronic Devices and Applications written by Trupti Ranjan Lenka and published by Bentham Science Publishers. This book was released on 2024-07-02 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoelectronic Devices and Applications presents reviews on recent advances in nanoelectronic device design and new directions for their practical use. The volume includes 16 edited chapters that cover novel material systems, band engineering, modelling and simulations, fabrication and characterization techniques, and their emerging applications. The discussions presented in this book are based on current understandings on innovations and future trends, and references are provided for advanced scholars. Chapter 1 presents an overview of recent innovations and future prospects in III-nitride semiconductor technologies for RF, power, digital and quantum applications. Chapter 2 reports new trends in GaN-based optical devices for sensing and micro-display applications. Chapter 3 shows current interests in nanophosphors and their utilizations in improving device performance of InGaN nanowire light-emitting diodes (LEDs). Recent studies on the effect of potential profile on the carrier transport in AlGaAs based double quantum well structures and their applications are presented in Chapter 4. The recent progress in high-electron-mobility transistors (HEMTs) is presented through Chapters 5, 6, and 7. A comprehensive review on β-Ga2O3 emphasizing material properties, growth approaches, and its applications for next-generation high-power nanoelectronics; the effect of dielectric layers on the characteristics of AlN/β-Ga2O3 HEMTs are presented in Chapter 8 and 9 respectively. Chapters 10-14 summarize the recent studies in field-effect transistors (FETs) adopting different materials and structures. Chapter 15 presents current research in 2D Tungsten Diselenide (WSe2) with special focus on the material properties, device structures, applications, and challenges. Finally, Chapter 16 presents a systematic review of memristors, and memristive semiconductor devices. The book is intended as a primary resource for elective subjects in advanced electronics and computer engineering courses at university level. Researchers and industry professionals will also learn about emerging trends and state-of-the-art research in nanoelectronics.
Book Synopsis GaN Transistors for Efficient Power Conversion by : Alex Lidow
Download or read book GaN Transistors for Efficient Power Conversion written by Alex Lidow and published by John Wiley & Sons. This book was released on 2019-08-12 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: An up-to-date, practical guide on upgrading from silicon to GaN, and how to use GaN transistors in power conversion systems design This updated, third edition of a popular book on GaN transistors for efficient power conversion has been substantially expanded to keep students and practicing power conversion engineers ahead of the learning curve in GaN technology advancements. Acknowledging that GaN transistors are not one-to-one replacements for the current MOSFET technology, this book serves as a practical guide for understanding basic GaN transistor construction, characteristics, and applications. Included are discussions on the fundamental physics of these power semiconductors, layout, and other circuit design considerations, as well as specific application examples demonstrating design techniques when employing GaN devices. GaN Transistors for Efficient Power Conversion, 3rd Edition brings key updates to the chapters of Driving GaN Transistors; Modeling, Simulation, and Measurement of GaN Transistors; DC-DC Power Conversion; Envelope Tracking; and Highly Resonant Wireless Energy Transfer. It also offers new chapters on Thermal Management, Multilevel Converters, and Lidar, and revises many others throughout. Written by leaders in the power semiconductor field and industry pioneers in GaN power transistor technology and applications Updated with 35% new material, including three new chapters on Thermal Management, Multilevel Converters, Wireless Power, and Lidar Features practical guidance on formulating specific circuit designs when constructing power conversion systems using GaN transistors A valuable resource for professional engineers, systems designers, and electrical engineering students who need to fully understand the state-of-the-art GaN Transistors for Efficient Power Conversion, 3rd Edition is an essential learning tool and reference guide that enables power conversion engineers to design energy-efficient, smaller, and more cost-effective products using GaN transistors.
Book Synopsis Gallium Nitride Power Devices by : Hongyu Yu
Download or read book Gallium Nitride Power Devices written by Hongyu Yu and published by CRC Press. This book was released on 2017-07-06 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: GaN is considered the most promising material candidate in next-generation power device applications, owing to its unique material properties, for example, bandgap, high breakdown field, and high electron mobility. Therefore, GaN power device technologies are listed as the top priority to be developed in many countries, including the United States, the European Union, Japan, and China. This book presents a comprehensive overview of GaN power device technologies, for example, material growth, property analysis, device structure design, fabrication process, reliability, failure analysis, and packaging. It provides useful information to both students and researchers in academic and related industries working on GaN power devices. GaN wafer growth technology is from Enkris Semiconductor, currently one of the leading players in commercial GaN wafers. Chapters 3 and 7, on the GaN transistor fabrication process and GaN vertical power devices, are edited by Dr. Zhihong Liu, who has been working on GaN devices for more than ten years. Chapters 2 and 5, on the characteristics of polarization effects and the original demonstration of AlGaN/GaN heterojunction field-effect transistors, are written by researchers from Southwest Jiaotong University. Chapters 6, 8, and 9, on surface passivation, reliability, and package technologies, are edited by a group of researchers from the Southern University of Science and Technology of China.
Book Synopsis Handbook of GaN Semiconductor Materials and Devices by : Wengang (Wayne) Bi
Download or read book Handbook of GaN Semiconductor Materials and Devices written by Wengang (Wayne) Bi and published by CRC Press. This book was released on 2017-10-20 with total page 775 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses material growth, device fabrication, device application, and commercialization of energy-efficient white light-emitting diodes (LEDs), laser diodes, and power electronics devices. It begins with an overview on basics of semiconductor materials, physics, growth and characterization techniques, followed by detailed discussion of advantages, drawbacks, design issues, processing, applications, and key challenges for state of the art GaN-based devices. It includes state of the art material synthesis techniques with an overview on growth technologies for emerging bulk or free standing GaN and AlN substrates and their applications in electronics, detection, sensing, optoelectronics and photonics. Wengang (Wayne) Bi is Distinguished Chair Professor and Associate Dean in the College of Information and Electrical Engineering at Hebei University of Technology in Tianjin, China. Hao-chung (Henry) Kuo is Distinguished Professor and Associate Director of the Photonics Center at National Chiao-Tung University, Hsin-Tsu, Taiwan, China. Pei-Cheng Ku is an associate professor in the Department of Electrical Engineering & Computer Science at the University of Michigan, Ann Arbor, USA. Bo Shen is the Cheung Kong Professor at Peking University in China.
Book Synopsis GaN-Based HEMTs for High Voltage Operation: Design, Technology and Characterization by : Eldad Bahat-Treidel
Download or read book GaN-Based HEMTs for High Voltage Operation: Design, Technology and Characterization written by Eldad Bahat-Treidel and published by Cuvillier Verlag. This book was released on 2012-06-08 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium nitride (GaN)-based High Electron Mobility Transistors (HEMTs) for high voltage, high power switching and regulating for space applications are studied in this work. Efficient power switching is associated with operation in high OFF-state blocking voltage while keeping the ON-state resistance, the dynamic dispersion and leakage currents as low as possible. The potential of such devices to operate at high voltages is limited by a chain of factors such as subthreshold leakages and the device geometry. Blocking voltage enhancement is a complicated problem that requires parallel methods for solution; epitaxial layers design, device structural and geometry design, and suitable semiconductor manufacturing technique. In this work physical-based device simulation as an engineering tool was developed. An overview on GaN-based HEMTs physical based device simulation using Silvaco-“ATLAS” is given. The simulation is utilized to analyze, give insight to the modes of operation of the device and for design and evaluation of innovative concepts. Physical-based models that describe the properties of the semiconductor material are introduced. A detailed description of the specific AlGaN/GaN HEMT structure definition and geometries are given along with the complex fine meshing requirements. Nitride-semiconductor specific material properties and their physical models are reviewed focusing on the energetic band structure, epitaxial strain tensor calculation in wurtzite materials and build-in polarization models. Special attention for thermal conductivity, carriers’ mobility and Schottky-gate-reverse-bias-tunneling is paid. Empirical parameters matching and adjustment of models parameters to match the experimental device measured results are discussed. An enhancement of breakdown voltage in AlxGa1-xN/GaN HEMT devices by increasing the electron confinement in the transistor channel using a low Al content AlyGa1-yN back-barrier layer structure is systematically studied. It is shown that the reduced sub-threshold drain-leakage current through the buffer layer postpones the punch-through and therefore shifts the breakdown of the device to higher voltages. It is also shown that the punch-through voltage (VPT) scales up with the device dimensions (gate to drain separation). An optimized electron confinement results both, in a scaling of breakdown voltage with device geometry and a significantly reduced sub-threshold drain and gate leakage currents. These beneficial properties are pronounced even further if gate recess technology is applied for device fabrication. For the systematic study a large variations of back-barrier epitaxial structures were grown on sapphire, n-type 4H-SiC and semi-insulating 4H-SiC substrates. The devices with 5 μm gate-drain separation grown on n-SiC owning Al0.05Ga0.95N and Al0.10Ga0.90N back-barrier exhibit 304 V and 0.43 m × cm2 and 342 V and 0.41 m × cm2 respectively. To investigate the impact of AlyGa1-yN back-barrier on the device properties the devices were characterized in DC along with microwave mode and robustness DC-step-stress test. Physical-based device simulations give insight in the respective electronic mechanisms and to the punch-through process that leads to device breakdown. Systematic study of GaN-based HEMT devices with insulating carbon-doped GaN back-barrier for high voltage operation is also presented. Suppression of the OFF-state sub-threshold drain leakage-currents enables breakdown voltage enhancement over 1000 V with low ON-state resistance. The devices with 5 μm gate-drain separation on SI-SiC and 7 μm gate-drain separation on n-SiC exhibit 938 V and 0.39 m × cm2 and 942 V and 0.39 m × cm2 respectively. Power device figure of merit of ~2.3 × 109 V2/-cm2 was calculated for these devices. The impacts of variations of carbon doping concentration, GaN channel thickness and substrates are evaluated. Trade-off considerations in ON-state resistance and of current collapse are addressed. A novel GaN-based HEMTs with innovative planar Multiple-Grating-Field-Plates (MGFPs) for high voltage operation are described. A synergy effect with additional electron channel confinement by using a heterojunction AlGaN back-barrier is demonstrated. Suppression of the OFF-state sub-threshold gate and drain leakage-currents enables breakdown voltage enhancement over 700 V and low ON-state resistance of 0.68 m × cm2. Such devices have a minor trade-off in ON-state resistance, lag factor, maximum oscillation frequency and cut-off frequency. Systematic study of the MGFP design and the effect of Al composition in the back-barrier are described. Physics-based device simulation results give insight into electric field distribution and charge carrier concentration depending on field-plate design. The GaN superior material breakdown strength properties are not always a guarantee for high voltage devices. In addition to superior epitaxial growth design and optimization for high voltage operation the device geometrical layout design and the device manufacturing process design and parameters optimization are important criteria for breakdown voltage enhancement. Smart layout prevent immature breakdown due to lateral proximity of highly biased interconnects. Optimization of inter device isolation designed for high voltage prevents substantial subthreshold leakage. An example for high voltage test device layout design and an example for critical inter-device insulation manufacturing process optimization are presented. While major efforts are being made to improve the forward blocking performance, devices with reverse blocking capability are also desired in a number of applications. A novel GaN-based HEMT with reverse blocking capability for Class-S switch-mode amplifiers is introduced. The high voltage protection is achieved by introducing an integrated recessed Schottky contact as a drain electrode. Results from our Schottky-drain HEMT demonstrate an excellent reverse blocking with minor trade-off in the ON-state resistance for the complete device. The excellent quality of the forward diode characteristics indicates high robustness of the recess process. The reverse blocking capability of the diode is better than –110 V. Physical-based device simulations give insight in the respective electronic mechanisms. Zusammenfassung In dieser Arbeit wurden Galliumnitrid (GaN)-basierte Hochspannungs-HEMTs (High Electron Mobility Transistor) für Hochleistungsschalt- und Regelanwendungen in der Raumfahrt untersucht. Effizientes Leistungsschalten erfordert einen Betrieb bei hohen Sperrspannungen gepaart mit niedrigem Einschaltwiderstand, geringer dynamischer Dispersion und minimalen Leckströmen. Dabei wird das aus dem Halbleitermaterial herrührende Potential für extrem spannungsfeste Transistoren aufgrund mehrerer Faktoren aus dem lateralen und dem vertikalen Bauelementedesign oft nicht erreicht. Physikalisch-basierte Simulationswerkzeuge für die Bauelemente wurden daher entwickelt. Die damit durchgeführte Analyse der unterschiedlichen Transistorbetriebszustände ermöglichte das Entwickeln innovativer Bauelementdesignkonzepte. Das Erhöhen der Bauelementsperrspannung erfordert parallele und ineinandergreifende Lösungsansätze für die Epitaxieschichten, das strukturelle und das geometrische Design und für die Prozessierungstechnologie. Neuartige Bauelementstrukturen mit einer rückseitigen Kanalbarriere (back-barrier) aus AlGaN oder Kohlenstoff-dotierem GaN in Kombination mit neuartigen geometrischen Strukturen wie den Mehrfachgitterfeldplatten (MGFP, Multiple-Grating-Field-Plate) wurden untersucht. Die elektrische Gleichspannungscharakterisierung zeigte dabei eine signifikante Verringerung der Leckströme im gesperrten Zustand. Dies resultierte bei nach wie vor sehr kleinem Einschaltwiderstand in einer Durchbruchspannungserhöhung um das etwa Zehnfache auf über 1000 V. Vorzeitige Spannungsüberschläge aufgrund von Feldstärkenspitzen an Verbindungsmetallisierungen werden durch ein geschickt gestaltetes Bauelementlayout verhindert. Eine Optimierung der Halbleiterisolierung zwischen den aktiven Strukturen führte auch im kV-Bereich zu vernachlässigbaren Leckströme. Während das Hauptaugenmerk der Arbeit auf der Erhöhung der Spannungsfestigkeit im Vorwärtsbetrieb des Transistors lag, ist für einige Anwendung auch ein rückwärtiges Sperren erwünscht. Für Schaltverstärker im S-Klassenbetrieb wurde ein neuartiger GaN-HEMT entwickelt, dessen rückwärtiges Sperrverhalten durch einen tiefgelegten Schottkykontakt als Drainelektrode hervorgerufen wird. Eine derartige Struktur ergab eine rückwärtige Spannungsfestigkeit von über 110 V.
Book Synopsis Vertical Gallium Nitride PowerDevices: Fabrication and Characterisation by : Rico Hentschel
Download or read book Vertical Gallium Nitride PowerDevices: Fabrication and Characterisation written by Rico Hentschel and published by BoD – Books on Demand. This book was released on 2021-01-03 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efficient power conversion is essential to face the continuously increasing energy consumption of our society. GaN based vertical power field effect transistors provide excellent performance figures for power-conversion switches, due to their capability of handling high voltages and current densities with very low area consumption. This work focuses on a vertical trench gate metal oxide semiconductor field effect transistor (MOSFET) with conceptional advantages in a device fabrication preceded GaN epitaxy and enhancement mode characteristics. The functional layer stack comprises from the bottom an n+/n--drift/p-body/n+-source GaN layer sequence. Special attention is paid to the Mg doping of the p-GaN body layer, which is a complex topic by itself. Hydrogen passivation of magnesium plays an essential role, since only the active (hydrogen-free) Mg concentration determines the threshold voltage of the MOSFET and the blocking capability of the body diode. Fabrication specific challenges of the concept are related to the complex integration, formation of ohmic contacts to the functional layers, the specific implementation and processing scheme of the gate trench module and the lateral edge termination. The maximum electric field, which was achieved in the pn- junction of the body diode of the MOSFET is estimated to be around 2.1 MV/cm. From double-sweep transfer measurements with relatively small hysteresis, steep subthreshold slope and a threshold voltage of 3 - 4 V a reasonably good Al2O3/GaN interface quality is indicated. In the conductive state a channel mobility of around 80 - 100 cm2/Vs is estimated. This value is comparable to device with additional overgrowth of the channel. Further enhancement of the OFF-state and ON-state characteristics is expected for optimization of the device termination and the high-k/GaN interface of the vertical trench gate, respectively. From the obtained results and dependencies key figures of an area efficient and competitive device design with thick drift layer is extrapolated. Finally, an outlook is given and advancement possibilities as well as technological limits are discussed.
