Download or read book The Epitaxial Growth of GaN and A1GaN GaN Heterostructure Field Effect Transistors HFET on Lithium Gallate LiGaO2 Substrates written by Sangbeom Kang and published by . This book was released on 2002 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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:

Download or read book GaN heterostructure field effect transistors written by and published by . This book was released on 1910 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A summary of the performance of AlGaN/GaN heterostructure field effect transistors on sapphire and SiC substrates are presented. High total power have been demonstrated by these devices at microwave frequencies. The prospects of utilizing the devices for high power integrated amplifiers are excellent although the issue of thermal management will need to be addressed especially for devices and circuits on sapphire.

Download or read book American Doctoral Dissertations written by and published by . This book was released on 2002 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book GaN based Materials and Devices written by Michael Shur and published by World Scientific. This book was released on 2004 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unique materials properties of GaN-based semiconductors havestimulated a great deal of interest in research and developmentregarding nitride materials growth and optoelectronic andnitride-based electronic devices. High electron mobility andsaturation velocity, high sheet carrier concentration atheterojunction interfaces, high breakdown field, and low thermalimpedance of GaN-based films grown over SiC or bulk AlN substratesmake nitride-based electronic devices very promising.

Download or read book An Experimental Study of AlGaN GaN Heterostructure Field effect Transistors HFETs written by Wei San Tan and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Epitaxial Growth of AlGaN GaN Heterostructure by Plasma assisted Molecular Beam Epitaxy for High Electron Mobility Transistor Applications written by 黃延儀 and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book GaN Transistors for Efficient Power Conversion written by Alex Lidow and published by Efficient Power Publications. This book was released on 2012 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 2014-09-15 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium nitride (GaN) is an emerging technology that promises to displace silicon MOSFETs in the next generation of power transistors. As silicon approaches its performance limits, GaN devices offer superior conductivity and switching characteristics, allowing designers to greatly reduce system power losses, size, weight, and cost. This timely second edition 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. With higher-frequency switching capabilities, GaN devices offer the chance to increase efficiency in existing applications such as DC–DC conversion, while opening possibilities for new applications including wireless power transfer and envelope tracking. This book is an essential learning tool and reference guide to enable power conversion engineers to design energy-efficient, smaller and more cost-effective products using GaN transistors. Key features: Written by leaders in the power semiconductor field and industry pioneers in GaN power transistor technology and applications. Contains useful discussions on device–circuit interactions, which are highly valuable since the new and high performance GaN power transistors require thoughtfully designed drive/control circuits in order to fully achieve their performance potential. Features practical guidance on formulating specific circuit designs when constructing power conversion systems using GaN transistors – see companion website for further details. A valuable learning resource for professional engineers and systems designers needing to fully understand new devices as well as electrical engineering students.

Download or read book Technology and Characterization of GaN based Heterostructure Field Effect Transistors HFETs written by Michael Fieger and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Process Development and Characterization of A1GaN GaN Heterostructure Field effect Transistors written by Andrew Taiann Ping and published by . This book was released on 1999 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book DC Microwave and Noise Properties of Gan Based Heterojunction Field Effect Transistors and Their Reliability Issues written by Congyong Zhu and published by . This book was released on 2013 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: AlGaN/GaN and InAlN/GaN-based heterojunction field effect transistors (HFETs) have demonstrated great high power and high frequency performance. Although AlGaN/GaN HFETs are commercially available, there still remain issues regarding long-term reliability, particularly degradation and ultimately device failure due to the gate-drain region where the electric field peaks. One of the proposed degradation mechanisms is the inverse-piezoelectric effect that results from the vertical electric field and increases the tensile strain. Other proposed mechanisms include hot-electron-induced trap generation, impurity diffusion, surface oxidation, and hot-electron/phonon effects. To investigate the degradation mechanism and its impact on DC, microwave, and noise performance, comprehensive stress experiments were conducted in both un-passivated and passivated AlGaN/GaN HFETs. It was found that degradation of AlGaN/GaN HFETs under reverse-gate-bias stress is dominated by inverse-piezoelectric effect and/or hot-electron injection due to gate leakage. Degradation under on-state-high-field stress is dominated by hot-electron/phonon effects, especially at high drain bias. Both effects are induced by the high electric field present during stress, where the inverse-piezoelectric effect only relates to the vertical electric field and the hot-electron effect relates to the total electric field. InAlN/GaN-based HFETs are expected to have even better performance as power amplifiers due to the large 2DEG density at the InAlN/GaN interface and better lattice-matching. Electrical stress experiments were therefore conducted on InAlN/GaN HFETs with indium compositions ranging from 15.7% to 20.0%. Devices with indium composition of 18.5% were found to give the best compromise between reliability and device performance. For indium compositions of 15.7% and 17.5%, the HFET devices degraded very fast (25 h) under on-state-high-field stress, while the HFET devices with 20.0% indium composition showed very small drain. It was also demonstrated that hot-electron/phonon effects are the major degradation mechanism for InAlN/GaN HFETs due to a large 2DEG density under on-state operations, whereas the inverse-piezoelectric effect is very small due to the small strain for the near lattice-matched InAlN barrier. Compared to lattice-matched InAlN/GaN HFETs, AlGaN/GaN HFETs have much larger strain in the barrier and about half of the drain current level; however, the hot electron/hot phonon effects are still important, especially at high drain bias.

Download or read book Current Collapse and Device Degradation in AlGaN GaN Heterostructure Field Effect Transistors written by Daniel Balaz and published by . This book was released on 2010 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Device Characterization and Modeling of Large Size GaN HEMTs written by Jaime Alberto Zamudio Flores and published by kassel university press GmbH. This book was released on 2012-08-21 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents a comprehensive modeling strategy for advanced large-size AlGaN/GaN HEMTs. A 22-element equivalent circuit with 12 extrinsic elements, including 6 capacitances, serves as small-signal model and as basis for a large-signal model. ANalysis of such capacitances leads to original equations, employed to form capacitance ratios. BAsic assumptions of existing parameter extractions for 22-element equivalent circuits are perfected: A) Required capacitance ratios are evaluated with device's top-view images. B) Influences of field plates and source air-bridges on these ratios are considered. The large-signal model contains a gate charge's non-quasi-static model and a dispersive-IDS model. THe extrinsic-to-intrinsic voltage transformation needed to calculate non-quasi-static parameters from small-signal parameters is improved with a new description for the measurement's boundary bias points. ALl IDS-model parameters, including time constants of charge-trapping and self-heating, are extracted using pulsed-DC IV and IDS-transient measurements, highlighting the modeling strategy's empirical character.

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 709 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.