Download or read book Frequency Characterization of Si SiC and GaN MOSFETs Using Buck Converter in CCM as an Application written by Keshava Gopalakrishna and published by . This book was released on 2013 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Present day applications using power electronic converters are focusing towards improving the speed, efficiency, and robustness. This led to the implementation of new devices in such converters where speed and efficiency are of concern. As silicon (Si) based power devices are approaching their operational performance limits with respect to speed, it is essential to analyze the properties of new devices, which are capable of replacing silicon based devices. Wide band-gap (WBG) semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN) are such materials, whose material properties show promising advantages for power electronic applications. This thesis focuses on the comparison of Si, SiC, and GaN based power devices. A detailed comparison in terms of the material performance based on their figures-of-merit will be discussed. In this thesis, a performance evaluation of Si, SiC, and GaN based power devices used as a high-side switch in a buck DC-DC converter will be performed. A buck converter having specifications: output voltage of 12 V and output power of 120 W. Initially, a design example for switching frequency of 100 kHz will be discussed. Further, an evaluation of the same for increase in switching frequencies will be performed. Finally, analyses of the power loss and efficiency of these devices will be made along with its validation using PSpice, SABER and MATLAB simulation software. It will be shown that the theoretical performance analyses are in accordance with the obtained simulated results. Finally, it will be shown that GaN based power devices have improved operational capabilities at high frequencies than those of Si and SiC.

Download or read book Wide Bandgap SiC GaN Power Devices Characterization and Modeling written by Ke Li and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compared to traditional silicon (Si) semiconductor material, wide bandgap (WBG) materials like silicon carbide (SiC) and gallium nitride are gradually applied to fabricate power semiconductor devices, which are used in power converters to achieve high power efficiency, high operation temperature and high switching frequency. As those power devices are relatively new, their characterization and modeling are important to better understand their characteristics for better use. This dissertation is mainly focused on those WBG power semiconductor devices characterization, modeling and fast switching currents measurement. In order to measure their static characteristics, a single-pulse method is presented. A SiC diode and a "normally-off" SiC JFET is characterized by this method from ambient temperature to their maximal junction temperature with the maximal power dissipation around kilowatt. Afterwards, in order to determine power device inter-electrode capacitances, a measurement method based on the use of multiple current probes is proposed and validated by measuring inter-electrode capacitances of power devices of different technologies. Behavioral models of a Si diode and the SiC JFET are built by using the results of the above characterization methods, by which the evolution of the inter-electrode capacitances for different operating conditions are included in the models. Power diode models are validated with the measurements, in which the current is measured by a proposed current surface probe.

Download or read book On the perspectives of SiC MOSFETs in high frequency and high power isolated DC DC converters written by Eial Awwad, Abdullah and published by Universitätsverlag der TU Berlin. This book was released on 2020-08-11 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing demand for efficiency and power density pushes Si-based devices to some of their inherent material limits, including those related to temperature operation, switching frequency, and blocking voltage. Recently, SiC-based power devices are promising candidates for high-power and high-frequency switching applications. Today, SiC MOSFETs are commercially available from several manufacturers. Although technology affiliated with SiC MOSFETs is improving rapidly, many challenges remain, and some of them are investigated in this work. The research work in this dissertation is divided into the three following parts. Firstly, the static and switching characteristics of the state-of-the-art 1.2 kV planar and double-trench SiC MOSFETs from two different manufacturers are evaluated. The effects of different biasing voltages, DC link voltages, and temperatures are analysed. The characterisation results show that the devices exhibit superior switching performances under different operating conditions. Moreover, several aspects of using the SiC MOSFET’s body diode in a DC/DC converter are investigated, comparing the body-diodes of planar and double-trench devices. Reverse recovery is evaluated in switching tests considering the case temperature, switching rate, forward current, and applied voltage. Based on the measurement results, the junction temperature is estimated to guarantee safe operation. A simple electro-thermal model is proposed in order to estimate the maximum allowed switching frequency based on the thermal design of the SiC devices. Using these results, hard- and soft-switching converters are designed, and devices are characterised as being in continuous operation at a very high switching frequency of 1 MHz. Thereafter, the SiC MOSFETs are operated in a continuous mode in a 10 kW / 100-250 kHz buck converter, comparing synchronous rectification, the use of the body diode, and the use of an external Schottky diode. Further, the parallel operation of the planar devices is considered. Thus, the paralleling of SiC MOSFETs is investigated before comparing the devices in continuous converter operation. In this regard, the impact of the most common mismatch parameters on the static and dynamic current sharing of the transistors is evaluated, showing that paralleling of SiC MOSFETs is feasible. Subsequently, an analytical model of SiC MOSFETs for switching loss optimisation is proposed. The analytical model exhibits relatively close agreement with measurement results under different test conditions. The proposed model tracks the oscillation effectively during both turn-on and –off transitions. This has been achieved by considering the influence of the most crucial parasitic elements in both power and gate loops. In the second part, a comprehensive short-circuit ruggedness evaluation focusing on different failure modes of the planar and double-trench SiC devices is presented. The effects of different biasing voltages, DC link voltages, and gate resistances are evaluated. Additionally, the temperature-dependence of the short-circuit capability is evaluated, and the associated failure modes are analysed. Subsequently, the design and test of two different methods for overcurrent protection are proposed. The desaturation technique is applied to the SiC MOSFETs and compared to a second method that depends on the stray inductance of the devices. Finally, the benefits of using SiC devices in continuous high-frequency, high-power DC/DC converters is experimentally evaluated. In this regard, a design optimisation of a high-frequency transformer is introduced, and the impact of different core materials, conductor designs, and winding arrangements are evaluated. A ZVZCS Phase-Shift Full-Bridge unidirectional DC/DC converter is proposed, using only the parasitic leakage inductance of the transformer. Experimental results for a 10 kW, (100-250) kHz prototype indicate an efficiency of up to 98.1% for the whole converter. Furthermore, an optimized control method is proposed to minimise the circulation current in the isolated bidirectional dual active bridge DC/DC converter, based on a modified dual-phase-shift control method. This control method is also experimentally compared with traditional single-phase shift control, yielding a significant improvement in efficiency. The experimental results confirm the theoretical analysis and show that the proposed control can enhance the overall converter efficiency and expand the ZVZCS range. Die steigende Nachfrage nach Effizienz und Leistungsdichte bringt Si-basierte eistungsbauteile an einige inhärente Materialgrenzen, die unter anderem mit der Temperaturbelastung, der Schaltfrequenz und der Blockierspannung in Zusammenhang stehen. In jüngster Zeit sind SiC-basierte Leistungsbauelemente vielversprechende Kandidaten für Hochleistungs- und Hochfrequenzanwendungen. Aktuell sind SiC-MOSFETs von mehreren Herstellern im Handel erhältlich. Obwohl sich die Technologie der SiC-MOSFETs rasch verbessert, werden viele Herausforderungen bestehen bleiben. Einige dieser Herausforderungen werden in dieser Arbeit untersucht. Die Untersuchungen in dieser Dissertation gliedern sich in die drei folgenden Teile: Im ersten Teil erfolgt, die statische und die transiente Charakterisierung der aktuellen 1,2 kV Planarund Doubletrench SiC-MOSFETs verschiedener Hersteller. Die Auswirkungen unterschiedlicher Gatespannungen, Zwischenkreisspannungen und Temperaturen werden analysiert. Die Ergebnisse der Charakterisierung zeigen, dass die Bauteile überlegene Schaltleistungen unter verschiedenen Betriebsbedingungen aufweisen. Darüber hinaus wird der Einsatz der internen SiC-Bodydioden in einem DC/DC-Wandler untersucht, wobei die Unterschiede zwischen Planar- und Doppeltrench-Bauteilen aufgezeigt werden. Das Reverse-Recovery-Verhalten wird unter Berücksichtigung der Gehäusetemperatur, der Schaltgeschwindigkeit, des Durchlassstroms und der angelegten Spannung bewertet. Anhand der Messergebnisse wird die Sperrschichttemperatur geschätzt, damit ein sicherer Betrieb gewährleistet ist. Ein einfaches elektrothermisches Modell wird vorgestellt, um die maximal zulässige Schaltfrequenz auf der Grundlage des thermischen Designs der SiC-Bauteile abzuschätzen. Anhand dieser Ergebnisse werden hart- und weichschaltende Umrichter konzipiert und die Bauteile werden im Dauerbetrieb mit einer sehr hohen Schaltfrequenz von 1 MHz untersucht. Danach werden die SiC-MOSFETs im Dauerbetrieb in einem 10 kW / 100-250 kHz-Tiefsetzsteller betrieben. Dabei wird die Synchrongleichrichtung, die Verwendung der internen Diode und die Verwendung einer externen Schottky-Diode verglichen. Außerdem wird die Parallelisierung von SiC-MOSFETs untersucht, bevor die Parallelschaltung der verschiedenen Bauelemente ebenso im kontinuierlichen Konverterbetrieb verglichen wird. Es wird der Einfluss der häufigsten Parametervariationen auf die statische und dynamische Stromaufteilung der Transistoren analysiert, was zeigt, dass eine Parallelisierung von SiC-MOSFETs möglich ist. Anschließend wird ein analytisches Modell der SiC-MOSFETs zur Schaltverlustoptimierung vorgeschlagen. Das analytische Modell zeigt eine relativ enge Übereinstimmung mit den Messergebnissen unter verschiedenen Testbedingungen. Das vorgeschlagene Modell bildet die Schwingungen sowohl beim Ein- als auch beim Ausschalten effektiv nach. Dies wurde durch die Berücksichtigung der wichtigsten parasitären Elemente in Strom- und Gatekreisen erreicht. Im zweiten Teil wird eine umfassende Bewertung der Kurzschlussfestigkeit mit Fokus auf verschiedene Ausfallmodi der planaren und double-trench SiC-Bauelemente vorgestellt. Die Auswirkungen unterschiedlicher Gatespannungen, Zwischenkreisspannungen und Gate-Widerstände werden ausgewertet. Zusätzlich wird die temperaturabhängige Kurzschlussfähigkeit ausgewertet und die zugehörigen Fehlerfälle werden analysiert. Anschließend wird die Auslegung und Prüfung von zwei verschiedenen Verfahren zum Überstromschutz evaluiert. Die „Desaturation“-Technik wird auf SiC-MOSFETs angewendet und mit einer zweiten Methode verglichen, welche die parasitäre Induktivität der Bauelemente nutzt. Schließlich wird der Nutzen des Einsatzes von SiC-Bauteilen in kontinuierlichen Hochfrequenz-Hochleistungs-DC/DC-Wandlern experimentell untersucht. In diesem Zusammenhang wird eine Designoptimierung eines Hochfrequenztransformators vorgestellt und der Einfluss verschiedener Kernmaterialien, Leiterausführungen und Wicklungsanordnungen wird bewertet. Es wird ein unidirektionaler ZVZCS Vollbrücken-DC/DC-Wandler vorgestellt, der nur die parasitäre Streuinduktivität des Transformators verwendet. Experimentelle Ergebnisse für einen 10 kW, (100-250) kHz Prototyp zeigen einenWirkungsgrad von bis zu 98,1% für den gesamten Umrichter. Abschließend wird ein optimiertes Regelverfahren verwendet, welches auf einem modifizierten Dual-Phase-Shift-Regelverfahren basiert, um den Kreisstrom im isolierten bidirektionalen Dual-Aktiv-Brücken-DC/DC-Wandler zu minimieren. Diese Regelmethode wird experimentell mit der herkömmlichen Single-Phase-Shift-Regelung verglichen. Hierbei zeigt sich eine deutliche Effizienzsteigerung durch die neue Regelmethode. Die experimentellen Ergebnisse bestätigen die theoretische Analyse und zeigen, dass die vorgeschlagene Regelung den Gesamtwirkungsgrad des Umrichters erhöhen und den ZVZCS-Bereich erweitern kann.

Download or read book Measurement Techniques to Characterize SiC GaN and Si Power MOSFETs for Transportation Applications written by Yan Bérubé and published by . This book was released on 2021 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization Methods for Submicron MOSFETs written by Hisham Haddara and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is true that the Metal-Oxide-Semiconductor Field-Eeffect Transistor (MOSFET) is a key component in modern microelectronics. It is also true that there is a lack of comprehensive books on MOSFET characterization in gen eral. However there is more than that as to the motivation and reasons behind writing this book. During the last decade, device physicists, researchers and engineers have been continuously faced with new elements which made the task of MOSFET characterization more and more crucial as well as difficult. The progressive miniaturization of devices has caused several phenomena to emerge and modify the performance of scaled-down MOSFETs. Localized degradation induced by hot carrier injection and Random Telegraph Signal (RTS) noise generated by individual traps are examples of these phenomena. Therefore, it was inevitable to develop new models and new characterization methods or at least adapt the existing ones to cope with the special nature of these new phenomena. The need for more deep and extensive characterization of MOSFET param eters has further increased as the applications of this device have gained ground in many new fields in which its performance has become more and more sensi tive to the properties of its Si - Si0 interface. MOS transistors have crossed 2 the borders of high speed electronics where they operate at GHz frequencies. Moreover, MOSFETs are now widely employed in the subthreshold regime in neural circuits and biomedical applications.

Download or read book Active Gate Drivers for High frequency Application of SiC MOSFETs written by Alejandro Paredes Camacho and published by . This book was released on 2020 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: The trend in the development of power converters is focused on efficient systems with high power density, reliability and low cost. The challenges to cover the new power converters requirements are mainly concentered on the use of new switching-device technologies such as silicon carbide MOSFETs (SiC). SiC MOSFETs have better characteristics than their silicon counterparts; they have low conduction resistance, can work at higher switching speeds and can operate at higher temperature and voltage levels. Despite the advantages of SiC transistors, operating at high switching frequencies, with these devices, reveal new challenges. The fast switching speeds of SiC MOSFETs can cause over-voltages and over-currents that lead to electromagnetic interference (EMI) problems.For this reason, gate drivers (GD) development is a fundamental stage in SiC MOSFETs circuitry design. The reduction of the problems at high switching frequencies, thus increasing their performance, will allow to take advantage of these devices and achieve more efficient and high power density systems.This Thesis consists of a study, design and development of active gate drivers (AGDs) aimed to improve the switching performance of SiC MOSFETs applied to high-frequency power converters. Every developed stage regarding the GDs is validated through tests and experimental studies. In addition, the developed GDs are applied to converters for wireless charging systems of electric vehicle batteries. The results show the effectiveness of the proposed GDs and their viability in power converters based on SiC MOSFET devices.

Download or read book An Accurate and Efficient Electro thermal Compact Model of Sic Power Mosfet Including Third Quadrant Behavior written by Arman Ur Rashid and published by . This book was released on 2021 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to narrower bandgap and lower critical electric field, silicon (Si) power devices have reached their limit in terms of the maximum blocking voltage capability. Exploiting this limitation, wide bandgap devices, namely silicon carbide (SiC) and gallium nitride (GaN) devices, are increasingly encroaching on the lucrative power electronics market. Unlike GaN, SiC devices can exploit most of the established fabrication techniques of Si power devices. Having substrate of the same material, vertical device structures with higher breakdown capabilities are feasible in SiC, unlike their GaN counterpart. Also, the excellent thermal conductivity of SiC, compared to GaN and Si, let SiC devices operate at higher temperatures ( ̃300°C). Hence, a more compact and cost-effective power electronic system can be designed with SiC devices without cumbersome cooling requirements. Specifically, SiC power MOSFETs have started to dominate applications such as three-phase inverters, PWM rectifiers, DC-DC converters in the 1.2 kV - 3.3 kV voltage range. However, SiC power MOSFET's full potential can only be harnessed with accurate and efficient simulation tools that enable optimally designed systems without multiple cost and time-consuming prototyping. Significant work has already been done on the compact modeling of SiC power MOSFET. However, those works focus on the first quadrant behavior. The third quadrant behavior, especially the gate bias dependent body diode characteristics, needs proper modeling for synchronous rectification, freewheeling diode action, dead time optimization, and EMI analysis. Further, the existing physics-based compact models lack efficient and continuous temperature scaling, which is essential for efficient and accurate simulation of power electronic systems with significant self-heating. This dissertation reports on an accurate and efficient electro-thermal model of the SiC power MOSFET that will include the third quadrant behavior with the body diode. In modeling body diode characteristics, the gate bias dependency and reverse recovery are included for the first time. For accurate switching characteristics, gate dependency of the input capacitance has been included. Accurate Miller capacitance modeling both at very low bias and at very high bias is ensured without adding too many model parameters. Avalanche-induced breakdown characteristics are included to make the model capable of predicting Safe Operating Area (SOA). Double pulse tests (DPT) at various temperatures were performed to validate the model's switching characteristics accuracy. A buck converter was implemented with the same half-bridge configuration as the DPTs to validate the model's performance with self-heating effects. Various other power electronics topologies are simulated to validate the accuracy and efficiency of the developed model. Detailed comparison with a previous physics-based model and a vendor-provided empirical model highlights the importance of the developed model in terms of accuracy and efficiency. Lastly, an easy-to-follow parameter extraction procedure has been described to enable broader use of the model among power electronics designers.

Download or read book Characterization Methods for Submicron Mosfets written by Hisham Haddara and published by . This book was released on 1996-01-31 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Metal-Oxide Semiconductor Field-Effect Transistor (MOSFET) is a key component in modern microelectronics. During the last decade, device physicists, researchers and engineers have been continuously faced with new elements making the task of MOSFET characterization increasingly crucial, as well as more difficult. The progressive miniaturization of devices has caused several phenomena to emerge and modify the performance of scaled-down MOSFETs. Localized degradation induced by hot carrier injection and Random Telegraph Signal (RTS) noise generated by individual traps are examples. It was thus unavoidable to develop new models and new characterization methods, or at least adapt the existing ones to cope with the special nature of these new phenomena. Characterization Methods for Submicron MOSFETs deals with techniques which show high potential for characterization of submicron devices. Throughout the book the focus is on the adaptation of such methods to resolve measurement problems relevant to VLSI devices and new materials, especially Silicon-on-Insulator (SOI). Characterization Methods for Submicron MOSFETs was written to provide help to device engineers and researchers to enable them to cope with the challenges they face. Without adequate device characterization, new physical phenomena and new types of defects or damage may not be well identified or dealt with, leading to an undoubted obstruction of the device development cycle. Audience: Researchers and graduate students familiar with MOS device physics, working in the field of device characterization and modeling. Also intended for industrial engineers working in device development, seeking to enlarge their understanding of measurement methods. The book additionally addresses device-based characterization for material and process engineers and for circuit designers. A valuable reference that may be used as a text for advanced courses on the subject.

Download or read book On the Perspectives of SiC MOSFETs in High frequency and High power Isolated DC DC Converters written by Abdullah Eial Awwad and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization and Modeling of Sic Multi Chip Power Modules written by Ryan Taylor and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The accelerating commercialization of wide bandgap technology has led to increased demand for accurate circuit-level simulation models of devices such as Silicon-Carbide (SiC) MOSFET power modules. These models assist with optimizing systems to minimize overshoot and electromagnetic interference (EMI) associated with wide bandgap (WBG) switching conditions. As a result, capturing these behaviors requires more detailed and advanced modeling and characterization techniques than traditional Silicon (Si) semiconductors. These advancements include improvements to the parasitic package model, transistor characterization, and computational efficiency of the synthesized model. In this dissertation, a commercially available half-bridge SiC power module is characterized and modeled in SPICE. Simulation and empirical characterization techniques are used to quantify the packaging parasitics of the module. These parasitics include self-inductances, mutual coupling terms, and baseplate capacitances (BPC) that are sensitive to the high di/dt and dv/dt events that occur during switching transitions. The simulation predictions and empirical measurements are used to cross-validate each other and determine the preferred method for quantifying each parasitic parameter. The SiC transistors are characterized using a combination of commercial equipment and custom measurement techniques. The characterization process is described in detail and sensitivities are uncovered in that are crucial to the modeling effort. The characterization includes an advanced conduction analysis (ACA) system that combined with a self-heating removal algorithm is capable of quantifying the short-channel behavior of the device at high voltage. Finally, the package model and SiC MOSFET characteristics are used to synthesize a compact behavioral model. The model is evaluated in terms of its accuracy through comparison of quantitative error metrics across a wide range of double pulse test (DPT) operating conditions. The model is also evaluated in a multi-level inverter simulation to determine its computational efficiency and convergence behavior. It is shown that the model is highly accurate across the selected range of operating conditions and is capable of converging quickly in complex circuit topologies.

Download or read book Fast Short circuit Protection for SiC MOSFETs in Extreme Short circuit Conditions by Integrated Functions in CMOS ASIC Technology written by Yazan Barazi and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wide bandgap power transistors such as SiC MOSFETs and HEMTs GaN push furthermore the classical compromises in power electronics. Briefly, significant gains have been demonstrated: better efficiency, coupled with an increase in power densities offered by the increase in switching frequency. HV SiC MOSFETs have specific features such as a low short-circuit SC withstand time capability compared to Si IGBTs and thinner gate oxide, and a high gate-to-source switching control voltage. The negative bias on the gate at the off-state creates additional stress which reduces the reliability of the SiC MOSFET. The high positive bias on the gate causes a large drain saturation current in the event of a SC. Thus, this technology gives rise to specific needs for ultrafast monitoring and protection. For this reason, the work of this thesis focuses on two studies to overcome these constraints, with the objective of reaching a good performance compromise between “CMS/ASIC-CMOS technological integration level-speed-robustness”. The first one, gathers a set of new solutions allowing a detection of the SC on the switching cycle, based on a conventional switch control architecture with two voltage levels. The second study is more exploratory and is based on a new gate-driver architecture, called multi-level, with low stress level for the SiC MOSFET while maintaining dynamic performances. The manuscript covers firstly the SiC MOSFET environment, (characterization and properties of SC behavior by simulation using PLECS and LTSpice software) and covers secondly a bibliographical study on the Gate drivers. And last, an in-depth study was carried out on SC type I & II (hard switch fault) (Fault under Load) and their respective detection circuits. A test bench, previously carried out in the laboratory, was used to complete and validate the analysis-simulation study and to prepare test stimuli for the design stage of new solutions. Inspired by the Gate charge method that appeared for Si IGBTs and evoked for SiC MOSFETs, this method has therefore been the subject of design, dimensioning and prototyping work, as a reference. This reference allows an HSF type detection in less than 200ns under 400V with 1.2kV components ranging from 80 to 120mOhm. Regarding new rapid and integrated detection methods, the work of this thesis focuses particularly on the design of a CMOS ASIC circuit. For this, the design of an adapted gate driver is essential. An ASIC is designed in X-Fab XT-0.18 SOICMOS technology under Cadence, and then packaged and assembled on a PCB. The PCB is designed for test needs and adaptable to the main bench. The design of the gate driver considered many functions (SC detection, SSD, segmented buffer, an "AMC", ...). From the SC detection point of view, the new integrated monitoring functions concern the VGS time derivative method which is based on a detection by an RC analog shunt circuit on the plateau sequence with two approaches: the first approach is based on a dip detection, i.e. the presence or not of the Miller plateau. The second approach is based on slope detection, i.e. the variability of the input capacitance of the power transistor under SC-HSF compared to normal operation. These methods are compared in the third chapter of the thesis, and demonstrate fault detection times between 40ns and 80ns, and preliminary robustness studies and critical cases are presented. A second new method is partially integrated in the ASIC, was designed. This method is not developed in the manuscript for valorization purposes. In addition to the main study, an exploratory study has focused on a modular architecture for close control at several bias voltage levels taking advantage of SOI isolation and low voltage CMOS transistors to drive SiC MOSFETs and improve their reliability through active and dynamic multi-level selection of switching sequences and on/off states.

Download or read book Performance of Devices Made of Large Band gap Semiconductors SiC and GaN written by Taizo Okayama and published by . This book was released on 2007 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Silicon (Si) and gallium arsenide (GaAs) devices have limitations for certain applications such as high-power and/or high-frequency due to their material properties. As a partial fulfillment of the requirements for the degree of doctor of philosophy in electrical and computer engineering, devices made using two promising substrate materials: silicon carbide (SiC) and gallium nitride (GaN) were studied for high-power and high-frequency applications, respectively. The SiC is considered as a suitable material for high-power devices such as double-implanted metal-oxide-semiconductor field-effect-transistor (DMOSFET), in which the current flows vertically to the substrate contact. The DMOSFET consists of several hundred cells connected in parallel, making it possible to sustain both high blocking voltage and high current. GaN grown on SiC is considered as a suitable material for high-frequency and high-power applications. High electron mobility transistor x (HEMT) fabricated with GaN and aluminum gallium nitride (AlGaN) utilizes a conduction band offset and piezoelectric polarization effect at the junction between these two materials to produce a highly conductive channel. However, in spite of their promises, the performance of both SiC DMOSFET and GaN HEMT devices, with respect to their Si and GaAs counterparts are not well understood. In this work, first the SiC DMOSFET devices were characterized for their threshold voltage, drain current and breakdown voltage stability and then GaN devices for their efficiency and linearity performance at high-frequency. The results of SiC DMOSFETs were fitted with simulation to determine the location of the interface charge responsible for instability in device behavior. The charge at the inner region of the junction termination extension has the most pronounced effect on the breakdown voltage instability. The interlayer dielectric (ILD) composition that can minimize the SiC DMOSFET instability problem is also determined considering several limitations on the maximum weight percentages of the boron and phosphorous constituent dopants in the boro-phospho-silicate glass (BPSG) ILD layer. The BPSG with a composition of 2.4 weight percent B and 5 weight percent P is projected as optimum for the processing conditions used for making the SiC DMOSFET of this study. Results of GaN HEMTs were compared with those of GaAs pseudomorphic HEMTs"--Abstract.

Download or read book Microwave Nonlinear Modeling and Active Frequency Multiplier Design for High Power Silicon carbide and Gallium nitride Field effect Transistors written by Kelvin Shing-Tak Yuk and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wide bandgap silicon-carbide (SiC) and gallium-nitride (GaN) FETs are the premier microwave solid-state power technology and are presently being deployed in a variety of commercial applications. However, performance-degrading self-heating and charge-trapping effects create new challenges for characterization and modeling of these devices. Accurate nonlinear models capable of predicting these effects are necessary to maximally exploit the benefits of this emerging, high power density technology. An empirical modeling methodology for the SiC MESFET and GaN HEMT using high power dynamic IV measurements to exploit and characterize self-heating and charge-trapping is applied over a vast range of electrothermal operating conditions. Nonlinear diode modeling and multibias, small-signal techniques are performed to create complete nonlinear models for SiC and GaN FETs, which are capable of predicting DC, pulsed, small- and large-signal RF behavior over a wide range of bias and frequency. The presented models are valid for drain currents beyond 2A, drain voltages greater than 50V and up to 10W at RF. These harmonically-accurate models permit the new application of CAD-based active frequency multiplier design for wide bandgap devices. Frequency doublers and triplers are demonstrated in SiC MESFET and GaN HEMT technology, producing some of the highest power, single-transistor microwave frequency multipliers to date. This work reports SiC- and GaN-based C-band frequency doublers with>5W output power and a GaN-based X-band frequency tripler with 1W output power.

Download or read book Silicon Carbide DMOSFET Characterization and Evaluation for Power Electronics Applications written by Ronald Green and published by . This book was released on 2010 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: As SiC MOSFET technology continues to mature, an assessment of device reliability becomes essential for the development of large power modules utilizing this technology. This dissertation investigated state-of-the-art 4H-SiC DMOSFETs for continuous power electronics applications. The research methodology consisted of performing a variety of electrical measurements that characterized device performance, and studied device stability and reliability. A 400-A power module utilizing SiC MOSFET technology was fabricated, tested and implemented in a continuous power conversion application circuit. The module features an integrated heat sink design and form factor that is compliant to commercial IGBT modules with similar rating. Switch-mode testing of the module in a power converter circuit demonstrated operation at 25 kW and 30 kHz switching frequency with an ambient temperature of 80°C. On-state performance of 1200 V class SiC MOSFET devices is currently limited by charge trapping at the SiC-SiO2 interface. As a result, the channel mobility is very low (much ≈ 20 cm 2/V·s) and the total specific on-resistance (Ron-sp) is dominated by the channel resistance. The temperature dependence of R on-sp was shown to be a function of the applied gate voltage. Two separate scattering mechanisms are responsible for the difference in the temperature response of Ron-sp that occurs at low and high gate voltages. The threshold voltage (VT) of these devices has strong temperature dependence which can limit the blocking performance. Subthreshold leakage current through the MOS channel increases with increasing temperature due to the shift in VT. This results in a higher drain leakage current during the off-state as the device temperature is raised. Device reliability may be impacted if VT is not set high enough to preclude subthreshold leakage current during off-state operation. It has been demonstrated that application of a negative gate bias can suppress this leakage current and enhance off-state performance. Switching performance of 4H-SiC MOSFET devices was characterized as a function of temperature in a double-pulse clamped inductive load test circuit. The total switching energy loss was found to decrease with increasing temperature due to the shift in VT. Modified High Temperature Gate Bias (MHTGB) and High Temperature Reverse Bias (HTRB) measurements on SiC MOSFET devices have achieved stress times of 100 and 50 hours respectively, with no failures. This work provides a first look at the long-term reliability of these devices. -- Abstract.

Download or read book On a Future for Silicon Carbide in Power Electronics Applications written by Levi Jason Gant and published by . This book was released on 2016 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon-based MOSFETs and IGBTs have long been the premiere options for semiconductor switches in power converter applications. However, each of these Si based device structures has limitations that constrain the performance capabilities of their intended applications. The recently commercialized SiC MOSFET allows for optimized application designs that are not constrained by the limitations of Si semiconductor switches as in traditional designs. This thesis will explore the device properties of SiC MOSFETs and compare them to the properties of Si MOSFETs and Si IGBTs. Device characterization methods for experimentally determining switching losses and conduction losses will be presented, along with special considerations to be made when dealing with wide band-gap devices. In order to demonstrate SiC MOSFETs system level optimization opportunities, this thesis will present a hard-switched 5 kW DC-to-DC converter that leverages the SiC devices in question to reach a system level efficiency of 99%. This converter will also be used as a platform to perform a head-to-head comparison of Si IGBTs and SiC MOSFETs in terms of overall system efficiency.

Download or read book Modeling and Simulation of High Speed Semiconductors Used in GaN and SiC Power Converters written by Ali Rahimi (Auteur de Modeling and simulation of high speed semiconductors used in GaN and SiC power converters) and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wide bandgap Semiconductors for Next generation Power Electronics Systems written by Grayson Zulauf and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Wide-bandgap power semiconductors promise to reshape the power electronics landscape, opening completely new use cases and increasing efficiency and power density in existing ones. Most notably, gallium nitride (GaN) and silicon carbide (SiC) were successfully commercialized in the past decades, with theoretical benefits over silicon of multiple orders-of-magnitude. When combined with soft-switching techniques and topologies, these wide-bandgap materials have the potential to move power conversion to MHz operating frequencies, radically shrinking power converters and enabling new fabrication methods with the frequency-driven reduction of passive component requirements. Unfortunately, soft-switched converters built at MHz frequencies have consistently underperformed their modeled efficiency, as this work shows for three DC-RF inverters at high- and very-high-frequency. These inverters have measured semiconductor losses nearly an order-of-magnitude greater than expected from manufacturer-provided simulation models, a discrepancy that demands investigation. These losses are attributed to the process of resonantly charging and discharging the output capacitance (Coss) of the power semiconductors, a loss mechanism termed "soft-switching losses" or "Coss losses." Our measurements constitute the first recognition of this problem in GaN HEMTs, and these initial measurements are then extended to SiC and Si MOSFETs, finding dependencies and scaling laws for each device class. To complete the understanding of losses at high-frequencies, the well-understood phenomenon in GaN HEMTs of dynamic on-resistance is then revisited. Our work conclusively shows that dynamic on-resistance cannot be accurately characterized using the standardized double-pulse-test, and uses the underlying physics to determine the parameters that must be controlled for accurate reporting. Using this measurement framework, this work extends the dynamic on-resistance measurements to MHz frequencies for the first time, finding that the majority of the dynamic effects in soft-switched converters occur below 1 MHz for the tested device. With both off-state and on-state losses precisely understood at MHz frequencies, the promise of high-frequency power conversion can finally be realized. While adopted widely in cell phones, inductive wireless power transfer for higher-value applications (e.g. electric vehicles) is beset by both low performance and high cost due to the limitations of litz wire. At 6.78 MHz, the first international industrial, scientific, and medical (ISM) band above 200 kHz, litz wire can be completely eliminated, paving the way to low cost, small, light, and high-performance systems. A 1 kW DC-DC converter that transfers power across a 2 cm gap with 6.6 cm diameter coils at over 95% efficiency is demonstrated, a new benchmark in power density and efficiency for MHz-frequency wireless power transfer. This performance would, plainly, not have been possible without the identification and quantification of Coss losses. Our future power, transportation, and computing infrastructures are dependent on the implementation of wide-bandgap power semiconductors to reduce size, weight, and cost while increasing efficiency to address the climate challenge. This thesis is our small contribution to meaningfully improving these semiconductors and showing what's possible for the next generation of power conversion.