Topic: Accelerating SiC Commercialization and Barriers to Overcome
Dr. Victor Veliadis is Executive Director & CTO of PowerAmerica, a member-driven consortium of industry, universities, and national labs accelerating the commercialization of energy efficient SiC and GaN power semiconductor technologies. At PowerAmerica, he has managed a budget of $150 million that he strategically allocated to over 200 industrial and University projects to catalyze SiC/GaN semiconductor and power electronics manufacturing, workforce development, and job creation. His PowerAmerica educational activities have trained 420 full-time students in collaborative industry/University WBG projects, and engaged over 4600 attendees in tutorials, short courses, and webinars. Dr. Veliadis is an ECE Professor at NCSU, and an IEEE Fellow and EDS Distinguished Lecturer. He has 27 issued U.S. patents, 6 book chapters, and over 150 peer-reviewed publications to his credit.
Prior to entering academia and taking an executive position at Power America in 2016, Dr. Veliadis spent 21 years in the semiconductor industry where his work included design, fabrication, and testing of SiC devices, GaN devices for military radar amplifiers, and financial and operations management of a commercial semiconductor fab. He has a Ph.D. degree in Electrical Engineering from John Hopkins University (1995).
Silicon devices are dominating power electronics due to their excellent starting material quality, streamlined fabrication, low-cost volume production, proven reliability and ruggedness, and design/circuit legacy. Although Si power devices continue to make progress, they are approaching their operational limits primarily due to their relatively low bandgap and critical electric field that result in high conduction and switching losses, and poor high temperature performance.
In this keynote, the favorable material properties of Silicon Carbide (SiC), which allow for highly efficient power devices with reduced form-factor and cooling requirements, will be outlined. The co-existence of Si, SiC, and GaN will be discussed, and their respective competitive advantages highlighted. High volume applications where SiC devices are displacing their Si counterparts will be reported. Wafer and device fabrication aspects will be summarized with an emphasis on the processes that do not carry over from the mature Si manufacturing world and are thus specific to SiC. The fab models of the vibrant SiC manufacturing infrastructure (that mirrors that of Si) will be presented. Barriers to SiC mass commercialization will be identified and analyzed. These include the higher than silicon device cost, defects that degrade performance and limit scalability of device area, reliability and ruggedness concerns, and the need for a trained workforce to skillfully insert SiC into power electronics systems.
Tat-Sing Paul Chow
Rensselaer Polytechnic Institute
Topic: Smart Power Devices and ICs with Wide and Ultrawide Bandgap Semiconductors
Prof. T. Paul Chow received his Ph.D. in Electrical Engineering from RPI in 1982. He was a member of the technical staff at GE Corporate Research and Development from 1977 to 1989. Since 1989, he has been with RPI, where he is now professor of the Electrical, Computer and Systems Engineering Department. He has been working in the smart power semiconductor device area since 1982. His present research activities include high-voltage silicon, GaAs and wide and extreme bandgap (particularly SiC and GaN) semiconductor power devices and ICs. He has published about archival 200 papers in scientific journals, has contributed ten chapters in technical textbooks, and has procured over nineteen patents. He is a Fellow of the IEEE.
The present status and latest technical frontiers (superjunctions, bidirectional transistors) for smart power devices and ICs made with wide and ultrawide semiconductors (particularly SiC and GaN) are presented and discussed. The basic device structures and their refinements, with respect to their potential and experimental performance, are evaluated and compared to their Si or GaAs counterparts. The integrated and unit processing technologies needed for the fabrication and manufacturing of these power devices are examined with their compatibility with commercial silicon foundry capabilities. The robustness and reliability of present commercial discrete power transistors are assessed. Future directions and challenges for the widespread adoption of these emerging smart power device technologies are identified.
Jih-Sheng Lai
Virginia Polytechnic Institute and State University
National Yang Ming Chiao Tung University
Topic: Outlook of Wide Bandgap Semiconductor Devices – From Application Aspects
Jih-Sheng (Jason) Lai received M.S. and Ph.D. degrees in electrical engineering from the University of Tennessee, Knoxville, in 1985 and 1989. After graduated, he joined Electric Power Research Institute (EPRI) Power Electronics Applications Center (PEAC) as the Senior Engineer and Manager. From 1993, he worked with the Oak Ridge National Laboratory as the Power Electronics Lead Scientist. In 1996, he switched to academia and joined Virginia Tech. Currently he is James S. Tucker Endowed Chair Professor and Director of Future Energy Electronics Center (FEEC). He also holds a Yushan Fellow Visiting Professor position at National Yang-Ming Jiao-Tung University, Taiwan. He published more than 500 refereed technical papers and received more than 30 U.S. patents in the area of high power electronics and their applications.
Dr. Lai is an IEEE Life Fellow. He received numerous awards including a Technical Achievement Award in 1995-Lockheed Martin Award Night and 2016-IEEE Gerald Kliman Innovation Award. His student teams won grand prizes in 2009 TI Engibous Analog Design Competition and 2011 IEEE International Future Energy Challenge. In 2016 Google Little Box Challenge, his team won the Top 3 Finalist among 2000+ international teams.
Wide bandgap (WBG) semiconductor devices have found their niche applications and the respected markets since the successful launches of early commercial products. The two distinct advantages of WBG device applications are high efficiency and high power density for power conversions. Although these two advantages are tightly related and are due to their fast switching speed, the application aspects appear to be diverged in different directions. The first commercial product that adopted WBG device is a photovoltaic (PV) microinverter which utilized SiC diode to improve efficiency. Recently the SiC MOSFETs were also successfully applied to electric vehicle (EV) traction motor drives to replace the traditional Si IGBT, which demonstrated not only significant efficiency gain, but also driving range improvement. The gallium nitride (GaN) devices, on the other hand, are finding their niches in size reduction for consumer products, on-board chargers, and potentially space applications. Currently the major markets are found in USB-C chargers and on-board chargers. With potentially more efficient direct drive techniques for d-mode GaN, more inverter-based applications including motor drives are expected to adopt GaN devices. This presentation will start with historical views and key features of WBG devices and then provide the outlook of their markets and applications.
Hirofumi Akagi
Tokyo Institute of Technology
Topic: Applications of SiC-MOSFET Modules to High-Power (100 kW or Higher) Dual-Active-Bridge (DAB) Converters
Hirofumi Akagi (IEEE Life Fellow) received his Ph.D. degree in electrical engineering from the Tokyo Institute of Technology, Tokyo, Japan, in March 1979. Since January 2000, he has been Professor, currently Distinguished Professor, with the Tokyo Institute of Technology. Prior to it, he was with Okayama University, Okayama, Japan from August 1991 to December 1999, and the Nagaoka University of Technology, Nagaoka, Japan from April 1979 to July 1991.
His research interests include power conversion systems and its applications to industry, transportation, and utility. He has authored and coauthored more than 140 IEEE Transactions/Journal papers, including three invited, single-author papers in Proceedings of the IEEE. According to Google Scholar, his lifetime citations reach over 64,000 times with an h-index of 104.
Dr. Akagi was a co-recipient of six IEEE Transactions Prize Paper Awards and 16 IEEE IAS Committee Prize Paper Awards. He was the recipient of the 2001 IEEE PELS William E. Newell Award, the 2004 IEEE IAS Outstanding Achievement Award, the 2008 IEEE Richard H. Kaufmann Award (an IEEE Technical Field Award), the 2012 IEEE PES Nari Hingorani Custom Power Award, the 2018 IEEE Medal in Power Engineering, and the 2020 EPE Gaston Maggetto Medal. He is currently the sole winner of both an IEEE medal and the EPE medal.
Dr. Akagi served as the President of the IEEE Power Electronics Society from January 2007 to December 2008 for two years, and as the IEEE Division II Director from January 2015 to December 2016 for two years.
This keynote pays attention to applications of SiC-MOSFET modules to dual-active-bridge (DAB) converters with a power rating of 100 kW or higher. The term “dual active bridge” results from circuit topology. These are also referred to as “bidirectional isolated dc-dc converters” coming from functionality. The DAB converters can be classified into the following two groups from applications:
Group 1: The dc voltage ratio of the input to the output is always equal to the transformer’s turn ratio. This situation occurs when the DAB converter is integrated into a converter cell or a submodule of a multilevel converter for achieving galvanic isolation between the input and the output.
Group 2: The voltage ratio is not equal to the turn ratio. This situation happens, for example, when the DAB converter is connected directly to a battery pack or system.
It has been known that Group 1 is higher in conversion efficiency than group 2 from the principles of operation. A 100-kW DAB converter consists mainly of two 1.2-V 400-A SiC-MOSFET H-Bridge (four-in-one) modules, and a 16-kHz transformer with unity turn ratio, where the input and output dc voltages are equal to 850 V. The speaker’s team verified experimentally that the DAB converter attained the following high efficiencies from the dc input to the dc output terminals at three different, but meaningful, operating conditions; 99.2% at 100 kW (the rated power of 100%), 99.5% (peak efficiency) at 34 kW, and 99.2% at 10 kW (a light load of 10%), maintaining the so-called “zero-voltage switching (ZVS)” in all the operating regions. These experimental results mean that the efficiency of the 100-kW DAB converter is 99.2% or higher in a broad range of 10 kW (10%) to 100 kW (100%). This speaker would expect the DAB converter to reach an extremely high efficiency of 99.6% or higher at the rated power by 2035 as a result of significant performance improvements of SiC-MOSFET modules and magnetic devices. This would allow the removal of cooling fans considered as life-span parts from heat sinks.
A research challenge is how to mitigate an efficiency reduction in group 2. It would be effective to introduce double-phase-shift (DPS) or triple-phase-shift (TPS) control to the DAB converter operating with a buck or boost mode, maintaining ZVS. The speaker’s team has designed, built and tested an experimental setup characterized by connecting the two identical 850-V 100-kV 16-kHz DAB converters in cascade. It was verified experimentally that the DAB converter reached an efficiency of 99.0 % at 100 kW, in which the input dc voltage is 750 V and the output dc voltage is 850 V.
Tsuyoshi FUNAKI
Osaka university
Topic: Packaging and components for wide band gap semiconductor power device application
He is a principal investigator (PI) of Power System Laboratory in Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering in Osaka University.
He is currently working on the research and development of renewable energy system and smart grid technology based on power electronics using incoming wide band gap semiconductor power devices; e.g. SiC, GaN, and also working on reliability assessment of power supply facilities.
He received the B.E. and M.E. degrees in electrical engineering and the Ph.D. degree all from Osaka University, Osaka, Japan. He was on the staff of Research Associate with Osaka University in 1994, and promoted to Associate Professor in 2001.
In 2002, he was an Associate Professor with Kyoto University.
Now, he has been a full Professor with Osaka University since 2008.
He is senior member of IEEE and belongs to the following societies.
IEEE Circuits and Systems Society
IEEE Industry Applications Society
IEEE Power & Energy Society
IEEE Power Electronics Society
IEEE Product Safety Engineering Society
IEEE Standards Association Individual
Wide band gap semiconductor realizes low loss high voltage unipolar power device, where bipolar structure is necessary for conventional Si semiconductor. The package of power device is required to have low parasitic inductance in wring and low thermal resistance for heat radiation to maximize fast switching characteristics of unipolar device. Also, circuit components to constitute power conversion circuit are required to have good high frequency characteristics in accommodating high frequency switching operation. This talk reviews activities and development trend in power device packaging and peripheral component in power conversion circuit with focusing on wide band gap semiconductor power devices.
Manabu Yanagihara
Power Stage Product Design Division, LSI Business Unit, Rohm Co., Ltd.
Topic: Enhancement-Mode AlGaN/GaN HEMTs With High Rated Forward Gate-Source Voltages
Dr. Manabu Yanagihara received the B.S. and Ph.D. degrees in applied physics from Tokyo University, Tokyo, Japan, in 1985 and 1998, respectively. He joined Matsushita Electric Industrial Co., Ltd. (currently Panasonic), Osaka, Japan in 1985. He started his carrier with the development of AlGaAs/GaAs HBTs for milli-meter wave applications. After then, he was involved with the development and mass-production of GaAs-MESFETs and InGaP/GaAs HBTs for power amplifiers used in cellular phones. From 2003 to 2020, he had been engaged in R&D and commercialization of high voltage (600 V) GaN power transistors for switching applications. In 2021, he was started working for Rohm Co., Ltd., Kyoto, Japan. Since then, he has been developing low voltage (less than 200 V) GaN power transistors.
Dr. Yanagihara is a member of the Japan Society of Applied Physics and was a program committee member of International Conference on Solid State Devices and Materials (SSDM) from 2018 to 2021.
Recently, AlGaN/GaN high electron mobility transistors (HEMTs) have started to be adopted for power switching applications and much attention is paid for their reliability and driving techniques. Their gate structures generally utilize a p-type GaN layer with Schottky-type gate metal, which enables enhancement-mode operation and reduced forward gate current. However, this type of gate structure limits the rated forward gate-source voltages around 6 V, obtained from time-dependent gate breakdown (TDGB) tests, while the gate operating voltages are around 5 V. Since the gate operating margins are small, the switching circuits require to insert extra gate resistances, which disable to exhibit inherent high-speed performances of GaN-HEMTs.
We have developed a new gate structure with a thin step structure around the p-GaN gate, which partially covers the surface of the AlGaN barrier layer. This novel structure dramatically reduces the gate leakage current and expands the rated voltage to 8 V. Therefore, it prevents the gate degradation, even if overshoot voltages exceeding 6 V generate during the gate driving.
We introduce the device structure and their performances including the mechanism of the improved gate robustness by TCAD simulations. The newly developed techniques will contribute to expansion of the GaN power HEMT market by higher reliability and improved design margin.
Chuck Huang
WIN Semiconductors Corp., Taiwan
Topic: The Challenges and Solutions RF GaN
Chuck Huang is Senior Assistant Vice President in WIN semiconductors and takes lead of marketing center. Chuck is devoted to investigate and promote compound semiconductors’ advanced technology. Chuck was a R&D director (MMIC design manager) in Transcom inc., where he focused on Ka band MMICs design and MMICs system; He joined Avago as a global account manager in 2004 and joined Samsung Taiwan as a Vice President in 2013.
Chuck received his Ph.D. degrees in electrical engineering from National Cheng Kung University and EMBA degree in National Taiwan University.
Topic:
The Challenges and Solutions RF GaN
Abstract:
With the obvious advantages of high frequency, high power and better efficiency, Compound Semiconductors have become indispensable technologies to drive innovative applications to advance our lifestyle.
With satellite communication and 6G communication era coming, we believe Compound Semiconductors will continue to play a key role in the future.
In this speech, we will elaborate the demand of future RF applications, highlight the challenges, and finally explore the correspondent technology solutions of the RF GaN.
Hiroshi Kono
Advanced Semiconductor Device Development Center,
Semiconductor Division,
Toshiba Electronic devices & Storage corporation
Topic: Performance and reliability improvement in Silicon carbide power devices.
Hiroshi Kono received the B. S. and M. S. and Ph. D in physics from Tohoku university in 2001, 2003, and 2006. He then joined corporate research & development center of Toshiba corporation in Japan, where he started studying silicon carbide power devices. Since 2012, he has been working at Toshiba semiconductor division for development of silicon carbide power MOSFETs. In 2021, he received the Ph. D in electrical engineering from Kyushu institute of technology. His present research interests are in developing high voltage power devices of silicon carbide and oscillation phenomenon of power devices.
Abstract: Performance improvement and application filed expansion of power devices are expected to achieve carbon-neutral society. Silicon carbide (SiC) power device market is expanding rapidly due to electric vehicles application. For further expansion, it is important to achieve both high device performance and reliability because of reliability concerns due to crystal defects in SiC and harsh operating environments. In this presentation, the challenges to improve the characteristics and reliability of SiC devices and the technological developments to solve them will be discussed.
Shyh-Chiang Shen
Vanguard International Semiconductor, Corp.
Topic: 8-inch GaN HEMT Technology for Power Electronic Applications
Shyh-Chiang Shen received his Ph.D. degree in electrical engineering at the University of Illinois at Urbana-Champaign (UIUC) in 2001. He joined the Georgia Institute of Technology in 2005 and is a Full Professor in the School of Electrical and Computer Engineering. His research is focused on wide bandgap semiconductor (WBG) microelectronics and optoelectronic devices with emphasis on physical device study, fabrication processing technique development, and device characterizations. His research has yielded 8 awarded U.S. patents, 5 book chapters, 200+ publications in refereed journals and conferences, and many invited seminar talks to date. In 2022, he took a leave of absence from Georgia Tech and joined Vanguard International Semiconductors, Corp. (VIS) in Taiwan as the Director of GaN program development. He is an editor of a book entitled Nitride Semiconductor LEDs; served as the Publication Chair for the IEEE WiPDA (2018 & 2019); and is an associate editor of the IEEE Transactions on Electron Devices. Dr. Shen is a senior member of the IEEE and a Fellow of the Optica (formerly known as the Optical Society of America.)
Abstract: Since the inception of GaN HEMT in the late 90’s, this transistor technology has evolved from research laboratory exploration to a commercial-grade manufacturing platform. The applications of GaN HEMT technologies have spread across a wide ranges of frequency spectrum as well as a variety of power ratings in both RF and power switching systems. Although superior device performance of GaN HEMTs was well recognized, wide acceptance of this technology falls back to a basic consideration of the cost vs. performance competitiveness. Naturally, an increase of the wafer size is an effective way to achieve a lower manufacturing cost. In the case of GaN HEMT manufacturing, it inevitably introduces new technology development hurdles to address fundamental material limitations. New engineering solutions ensued, and GaN HEMT manufacturing in an 8-inch fab has become possible in recent years, with success. This talk will present the progress of 8-inch GaN HEMT technology development and discuss the feasibility of GaN HEMTs’ expanding application space for 650 V and beyond.
Masayoshi Tarutani
Mitsubishi Electric Corporation
Topic: Technology Trends of Si and SiC Chips and Modules for Power Electronics Application
Dr. Masayoshi Tarutani received the B.S. and M.S. and Ph.D. from the Department of Applied Physics, Faculty of Engineering, Osaka University in 1991, 1993 and 1995. In 1996, he joined Advanced Technology Research and Development Center of Mitsubishi Electric Corporation. He belonged to the semiconductor device development department and was engaged in the development of basic process technology for high dielectric memory capacitors of DRAM, and many other devices of carbon nanotubes and SiC. In 2011, he moved to the power device works of Mitsubishi Electric Corporation, where he was responsible for the launch of the SiC wafer process line, and the device structure development of the 6th and 7th generation Si-IGBTs. The development of the bonding structure of the chips in the power module is also his research items. Currently, he supports the development of power device technology as the chief engineer of the power device works.
Abstract: In order to realize a carbon-neutral society, there is a growing need for highly efficient power devices and modules. These areas of application are electrical products that are in the stage of power generation, distribution, electrification and consumption. In addition, it covers a wide current and voltage range, including consumer, industrial, automotive, electric railway, and FACTS and HVDC applications. Power semiconductor modules are one of the key parts for realizing such an ideal society (Energy-wise society).
In this presentation, he will introduce the latest generation of Si chip technology and explain the latest topics in SiC chip technology. Regarding SiC, examples of stability and reliability of electrical properties are also discussed. The latest generation of power modules with these chips will also be introduced.