Download or read book Design space and Scalable Technology for GaN Based Power Transistors written by Daniel Piedra (Ph. D.) and published by . This book was released on 2018 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: As silicon devices approach their intrinsic material and technological limit, there is an opportunity for alternative semiconductor materials to push the performance of electronics forward. Gallium nitride (GaN) has demonstrated very promising performance for advanced electronics, but there is still room for improvement. This thesis discusses several new transistor designs to improve the performance of GaN-based power devices as well as demonstrations of their scaling potential and integration capability with silicon. Specifically, we have developed a wide-periphery GaN fin-based high electron mobility transistor process for power switching. The process was developed with emphasis on the passivation, field plates, gate periphery scaling, and packaging. A CMOS compatible GaN processing technology on 200-mm wafers was developed and optimized, with particular attention focused on the recess etching through the wide-bandgap AlGaN barrier to reduce the contact resistance. A study of a heterogeneous integration technology to integrate GaN and Si devices was conducted. This involved an approach to monolithically integrate GaN and Si devices which used a bonded SOI wafer with a Si (111) substrate and Si (100) device layer with windows opened to access the (111) layer to selectively grow GaN. Characterization of the transistor properties in GaN windows of different sizes was performed to qualify the optimal window size for power devices in future integrated systems.

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 GaN Electronics for High temperature Applications written by Mengyang Yuan and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium nitride (GaN) is a promising candidate for harsh environment electronics, thanks to its excellent material properties, which have given rise to high-performance (room temperature) transistors for radio frequency (RF), power, micro-electro-mechanical systems (MEMS), and mixed-signal applications. Previous works on high-temperature (HT) electronics have been typically limited to two aspects, namely, the high-temperature robustness of discrete transistors and basic circuit building blocks, which are mainly combinational logic. While these studies offer a strong indication of the potential of GaN transistor technology for HT applications, the development of HT (500 °C) GaN integrated circuit (ICs) is still at its early stage due to the low degree of complexity and integration demonstrated so far. Major challenges in the realization of GaN HT-robust sequential logic circuits or more complex systems is the lack of a scalable technology. This thesis aims to advance the integration technology of GaN HT electronics by demonstrating a comprehensive HT (500°C) enhancement-mode (E-mode) GaN-on-Si technology from device to circuit perspectives: (1) a scalable device technology based on p-GaN-gate AlGaN/GaN high-electron-mobility transistors (HEMTs) with high uniformity, which is optimized for HT operation and demonstrated to offer robust performance at least up to 500 °C with the help of in-house developed packaging technology and characterization platform, (2) compact modeling of monolithically integrated enhancement/depletion-mode HEMTs up to 500 °C HEMTs, (3) robustness-driven circuit design based on GaN technology, (4) demonstration of GaN-based combinational and sequential building blocks including inverter, NAND, NOR, ring oscillators, ROM, SRAM, D Latch, D Flip-Flop operational up to 500 °C.

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 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.

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 Highly Integrated Gate Drivers for Si and GaN Power Transistors written by Achim Seidel and published by Springer Nature. This book was released on 2021-03-31 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores integrated gate drivers with emphasis on new gallium nitride (GaN) power transistors, which offer fast switching along with minimum switching losses. It serves as a comprehensive, all-in-one source for gate driver IC design, written in handbook style with systematic guidelines. The authors cover the full range from fundamentals to implementation details including topics like power stages, various kinds of gate drivers (resonant, non-resonant, current-source, voltage-source), gate drive schemes, driver supply, gate loop, gate driver power efficiency and comparison silicon versus GaN transistors. Solutions are presented on the system and circuit level for highly integrated gate drivers. Coverage includes miniaturization by higher integration of subfunctions onto the IC (buffer capacitors), as well as more efficient switching by a multi-level approach, which also improves robustness in case of extremely fast switching transitions. The discussion also includes a concept for robust operation in the highly relevant case that the gate driver is placed in distance to the power transistor. All results are widely applicable to achieve highly compact, energy efficient, and cost-effective power electronics solutions.​

Download or read book Monolithic Integration in E Mode GaN Technology written by Maik Peter Kaufmann and published by Springer Nature. This book was released on 2022-10-26 with total page 185 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive, all-in-one source on design of monolithic GaN power ICs. It is written in handbook style with systematic guidelines and includes implementation examples. It covers the full range from technology fundamentals to implementation details including design techniques specific for GaN technology. It provides a detailed loss analysis based on comparative measurements between silicon and GaN based converters to provide an understanding of the relations between design choices and results which can be transferred to other power converter systems.

Download or read book GaN Transistor Modeling for RF and Power Electronics written by Yogesh Singh Chauhan and published by Elsevier. This book was released on 2024-05-31 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: GaN Transistor Modeling for RF and Power Electronics: Using The ASM-GaN-HEMT Model covers all aspects of characterization and modeling of GaN transistors for both RF and Power electronics applications. Chapters cover an in-depth analysis of the industry standard compact model ASM-HEMT for GaN transistors. The book details the core surface-potential calculations and a variety of real device effects, including trapping, self-heating, field plate effects, and more to replicate realistic device behavior. The authors also include chapters on step-by-step parameter extraction procedures for the ASM-HEMT model and benchmark test results. GaN is the fastest emerging technology for RF circuits as well as power electronics. This technology is going to grow at an exponential rate over the next decade. This book is envisioned to serve as an excellent reference for the emerging GaN technology, especially for circuit designers, materials science specialists, device engineers and academic researchers and students. This book provides an overview of the operation and physics of GaN-based transistors All aspects of the ASM-HEMT model for GaN circuits, an industry standard model, are described in depth by the developers of the model Parameter extraction of GaN devices and measurement data requirements for GaN model extraction are detailed

Download or read book Advanced GaN Devices and Technology for Rf and Power Switching Applications written by Bo Song and published by . This book was released on 2016 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: GaN-based devices show great potential for high-speed RF power applications as well as power switching applications due to the high electron velocity and high breakdown field in GaN over Si, GaAs and SiC. Another unique property of III-V nitride materials (GaN, AlN, InN) is polarization, which can be engineered to induce 2-dimensional electron gas (2DEG) at heterojunction interfaces as well as induce 3-D electron gas in thick (bulk) layers by grading the alloy composition of the layers, e.g. AlGaN, without impurity doping. This unconventional doping scheme is termed as polarization-doping or Pi-doping. This work focuses on device development and proposals to advance GaN technologies for RF and power switching applications. During the quest to realize THz GaN transistors, it has been identified that the ultimate factors limiting the GaN high electron mobility transistors (HEMTs) are the intrinsic transconductance (gm) and the fringing capacitance (Cfringing) associated with the T-gate: speed gm/Cfringing. In InAlN/GaN HEMTs, the device current gain cut-off speed is increased from 230 GHz to >300 GHz by reducing Cfringing and further increased to ~ 400 GHz by improving gm. Effects of scaling the source-drain distance on ultra-scaled devices are also studied. Low leakage and low current collapse (or frequency dispersion) are crucial for transistors. A record-low leakage of 1x10-12 A/mm simultaneously with a low current collapse is achieved in AlGaN/GaN-on-Si HEMTs employing the regrown ohmic contact technology. The device improvement is attributed to the contact regrowth since generation of surface traps is minimized by avoiding the conventional high temperature annealing process to form alloyed ohmic contacts. For high-voltage high-current power switching applications (>100 kW), vertical devices are highly desirable over lateral ones. To this end, we have proposed a series of GaN devices grown on bulk GaN substrates and employing the unique feature in the GaN material family - polarization doping. Analytical modeling suggests that at the same breakdown voltage, a up to 2x lower specific on-resistance (Ron,sp) can be achieved in Pi-doped devices compared to impurity doped GaN power devices. High voltage impurity and Pi-doped GaN p-n diodes with a breakdown voltage (BV) >1.2 kV and avalanche breakdown capability have been developed experimentally. Another concept called GaN Lateral Polar Super Junctions (LPSJ) is also proposed and theoretically analyzed, featuring uniformly Pi-doped n/p-pillars to overcome the conventional tradeoff between BV and Ron,sp in a unipolar drift region of a power device. The design space for GaN LPSJs is explored using a 2D analytical model of BV and Ron,sp under both charge balanced and imbalanced conditions.

Download or read book Advanced SPICE Model for GaN HEMTs ASM HEMT written by Sourabh Khandelwal and published by Springer Nature. This book was released on 2022-01-01 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses in detail the Advanced SPICE Model for GaN HEMTs (ASM-HEMT), a new industry standard model for GaN-based power and RF circuit design. The author describes this new, standard model in detail, covering the different components of the ASM GaN model from fundamental derivations to the implementation in circuit simulation tools. The book also includes a detailed description of parameter extraction steps and model quality tests, which are critically important for effective use of this standard model in circuit simulation and product design. Coverage includes both radio-frequency (RF), and power electronics applications of this model. Practical issues related to measurement data and parameter extraction flow are also discussed, enabling readers easily to adopt this new model for design flow and simulation tools. Describes in detail a new industry standard for GaN-based power and RF circuit design; Includes discussion of practical problems and their solutions in GaN device modeling; Covers both radio-frequency (RF) and power electronics application of GaN technology; Describes modeling of both GaN RF and power devices.

Download or read book Simulation and Fabrication of GaN based Vertical and Lateral Normally off Power Transistors written by Yuhao Zhang (S.M.) and published by . This book was released on 2013 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is divided in two parts. First, self-consistent electro-thermal simulations have been performed for single finger and multi-finger GaN-based vertical and lateral power transistors and were validated with experimental DC characteristics. The models were used to study the thermal performance of GaN-based vertical metal oxide semiconductor field-effect transistors (MOSFETs) and the lateral high electron mobility transistors (HEMTs) designed for different breakdown voltage application and at different size scaling levels. The comparison between two structures revealed that the vertical MOSFETs have the potential to achieve an up to 50% higher thermal performance, especially for higher breakdown voltage and higher size scaling level designs. Second, normally-off lateral MOS-HEMTs were developed by the combination of fluorine plasma treatment and high-temperature gate oxide deposition. Record performances have been achieved for the fluorinated MOS-HEMTs with a threshold voltage >3.5 V, a low on-resistance ~ 2 m[Omega]·cm2, a small threshold voltage hysteresis ~0.15 V, high enhancement-mode channel mobility ~ 1000 cm2V-1s-1, a breakdown voltage ~ 780 V, no current collapse and a stability with 24 h continuous on-state operation at 250 oC. In addition, an analytical model for the threshold voltage of fluorinated MOS-HEMTs was established for the first time, to enable accurate design and engineering of the threshold voltage for MOS-HEMTs. This novel technology has been demonstrated as promising to fabricate high-performance normally-off MOS-HEMTs.

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:

Download or read book Development of Gallium Nitride Power Transistors written by Daniel Piedra (M. Eng.) and published by . This book was released on 2011 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: GaN-based high-voltage transistors have outstanding properties for the development of ultra-high efficiency and compact power electronics. This thesis describes a new process technology for the fabrication of GaN power devices optimized for their use in efficient power distribution systems in computer micro-processors. An existing process flow was used to fabricate the baseline single-finger transistors and additional process steps were developed and optimized to fabricate multi-finger devices with total gate widths up to 12mm. These transistors offer the current and on-resistance levels required by future GaN-based power converters. Transistors with various gate widths were fabricated and characterized by DC and capacitancevoltage measurements to study how the main transistor metrics scale with gate width.

Download or read book Dynamic ON resistance in High Voltage GaN Field effect transistors written by Donghyun Jin and published by . This book was released on 2014 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, the development of energy efficient electrical power management systems has received considerable interest due to its potential to realize significant energy savings for the world. With current Si-based power electronics system being matured, GaN Field-Effect-Transistors have emerged as a disruptive technology with great potential that arises from the outstanding material properties of GaN. However, in spite of great progress in GaN device fabrication, electrical reliability and a number of unique anomalies of GaN remain key challenges that prevent the wide deployment of this technology. In particular, the dynamic ON-resistance (RON), in which the RON of the transistor remains high for a certain period of time after a high-voltage OFF-ON switching event, is a critical concern. This phenomenon greatly affects the efficiency of electrical power management circuits based on GaN power transistors. This thesis investigates in depth this important issue. Firstly, we have developed a new dynamic RON measurement methodology which can observe dynamic RON transients after OFF-to-ON switching events over many decades in time. We have experimentally demonstrated this technique on GaN-on-SiC high-voltage HEMTs (High-Electron- Mobility-Transistors). The possible origin of the mechanisms responsible for dynamic RON in these devices has been postulated. Through our new technique, the impact of high-power stress on dynamic RON has been investigated as well. The results emphasize the importance of studying dynamic RON characteristics over very short time scale when conducting reliability studies of GaN transistors. Secondly, high-voltage GaN-on-Si MIS (Metal-Insulator-Semiconductor) HEMTs designed for > 600 V switching operation have been investigated. Excessive electron trapping leading to total current collapse has been observed. We have carried out an extensive characterization of this phenomenon and we have proposed "Zener trapping" as the responsible mechanism. In this view, electron trapping takes place inside the AlGaN/GaN heterostructure through a tunneling process under high-electric-field. The understanding derived here suggests that this effect can be mitigated through attention to defect control during epitaxial growth and appropriate design of the field plate structure of the device. Our findings in this thesis provide a path to achieve high performance GaN power transistors with minimum dynamic RON effects.

Download or read book Experimental and Simulation Study of GaN Device Size Limitations for High Efficiency Power Converters written by Florian Rigaud-Minet and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays the electrification of our society leads to a huge demand for technologies related to power conversion systems. Lateral Gallium Nitride (GaN) transistors made on silicon wafers were shown to be more adapted for high-efficiency power conversion over their silicon counterparts in the mid-voltage range (100 V-1000 V) at a reasonable cost. The targeted power converters are phone or laptop chargers, on-board chargers in electric vehicles, data center power supplies, micro-inverters for photovoltaics and more-electric aircraft power converters. Power transistor scaling may be interesting to improve converter efficiency. Indeed, it could, on the one hand, reduce the transistor-related charges QXX decreasing the switching time and hence the switching losses or on the other hand, decrease the on-state static resistance RDS,ON. However, the scaling should also result in a reduction of the device breakdown voltage as well as a switching that is more sensitive to parasitics that may have disturbed its stability/losses. In this thesis, the electric field distribution management and the switching losses of lateral 650 V rated GaN--on-Silicon power devices built at CEA-LETI are studied. To do so, an electrical and physical failure analysis was performed to identify the voltage limitation of lateral GaN-on-Si diode test vehicles with different layouts and substrate connections. To study the electric field distribution by Technology Computer Assisted Design (TCAD) using Synopsys® SentaurusTM, the electric field variation should reproduce the experimental breakdown voltage. Thus, a buffer trap calibration method based on experimental protocols was initiated. Finally, a new hard switching characterization test bench was set up to study the transistor design and manufacturing process impact on the switching losses of lateral GaN-on-Si transistors. The results help to derive guidelines for the technology and design scaling of the future generations of fully recessed GaN-on-Si Metal Insulator Semiconductor High Electron Mobility Transistor (MIS-HEMT).

Download or read book A Compact Transport and Charge Model for GaN based High Electron Mobility Transistors for RF Applications written by Ujwal Radhakrishna and published by . This book was released on 2013 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium Nitride (GaN)-based high electron mobility transistors (HEMTs) are rapidly emerging as front-runners in high-power mm-wave circuit applications. For circuit design with current devices and to allow sensible future performance projections from device engineering in such a rapidly evolving technology, compact device models are essential. In this thesis, a physics-based compact model is developed for short channel GaN HEMTs. The model is based on the concept of virtual source (VS) transport originally developed for scaled silicon field effect transistors. Self-consistent current and charge expressions in the model require very few parameters. The parameters have straightforward physical meanings and can be extracted through independent measurements. The model is implemented in Verilog-A and is compatible with state of the art circuit simulators. The new model is calibrated and validated with experimental DC I-V and S-parameter measurements of fabricated devices. Using the model, a projection of cut-off frequency (f-[tau]) of GaN-based HEMTs with scaling is performed to highlight performance bottlenecks.