Tutorial Sessions

Track 1

Topic: SiC power device technology – an overview starting with material aspects and concluding with examples how SiC can contribute to a greener future for all of us

Abstract: SiC was known for decades as a powerful alternative to silicon for high voltage high power devices. After breakthroughs in substrate technology around 30 years ago real R&D on devices was enabled. Since 2001 devices are available commercially, however, the first 15 years of Sic in power have been characterized by small niche like use cases and many ups and downs. However, with a braoder availability of MOSFETs and the move to 150mm wafer technology the interest in the industry grew tremendously. Today we have CAGRs being six to 7 times higher than for silicon on power, and an end of the path is not yet visible.

The tutorial will deal with the crucial aspects of SiC technology like enabling low cost wafer technologies, designing reliable power transistors, creating the right ecosystem around the chip by using proper package technologies and smart driving techniques. Finally, a look into various applications will complete the tutorial, analyzing mainly system benefits and value propositions of the new technology.

Dr. Peter Friedrichs was born in 1968 in Aschersleben, Germany. After achieving his Dipl.-Ing. in microelectronics from the Technical University of Bratislava in 1993, he started a Ph.D work at the Fraunhofer Institut FhG-IIS-B in  Erlangen. His focus area of expertise was the physics of the MOS interface in SiC power MOSFETs.  In 1996 he joined the Corporate Research of the Siemens AG and was involved in the development of power switching devices on SiC, mainly power MOSFETs and vertical junction FETs.

Peter Friedrichs joined SiCED GmbH & Co. KG, a company being a joint venture of Siemens and Infineon and originated from the former Siemens research group, on March the 1st, 2000. Since July 2004 he was the managing director of SiCED, responsible for all technical issues. In 2009 he achieved the Dipl.-Wirt.-Ing. From the University of Hagen. After the integration of SiCED’s activities into Infineon he joined Infineon on April 1st, 2011 and acts currently as Vice President SiC. He is a member of the ECPE board and acts as co-chair for the JEDEC JC70.2 committee. He holds numerous patents in the field of SiC power devices and technology and is an author or co/author of more than 50 scientific papers and conference contributions.

Topic: SiC Power Device Status, Challenges, and Insertion in Medium Voltage Converters


Silicon (Si) power devices have dominated power electronics due to their low cost volume production, excellent starting material quality, ease of processing, and proven reliability. Although Si power devices continue to make significant 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 tutorial, the favorable material properties of Silicon Carbide (SiC), which allow for highly efficient power devices with reduced form factor and reduced cooling requirements, will be highlighted. High impact application opportunities, where SiC devices are expected to displace their incumbent Si counterparts, will be discussed. These include variable frequency drives for efficient high power electric motors at reduced overall system cost; automotive and rail power electronics with reduced losses and reduced cooling requirements; novel data center topologies with reduced cooling loads and higher efficiencies; “more electric aerospace” with weight, volume, and cooling system reductions contributing to energy savings; and more efficient, flexible, and reliable grid applications with reduced system footprint.

SiC fab models will be presented and the vibrant U.S. SiC device manufacturing infrastructure will be discussed. Fab considerations and cost reduction strategies will be highlighted elucidating the path to the projected $1B SiC device market by 2022. Device fabrication aspects will be outlined with an emphasis on the processes that do not carry over from the mature Si manufacturing world and are thus specific to SiC. Barriers to SiC mass commercialization will be identified and detailed.

The tutorial will include HV SiC MOSFETs and 15kV SiC IGBT based applications of high power and MV power converters in all industry sectors – HVDC, FACTS, power quality, MV motor drives (including high-speed machines with high fundamental frequency), MVDC grids, MV grid-connected converters for renewables such as solar, wind, etc., MV converters for mining applications, MV converters for traction applications, MV converters for industrial applications such as steel mills, cement, and others; with present OEM solutions. The opportunities for HV SiC devices for MV and high power converters and utility applications and the challenges to applying these HV SiC devices successfully will be presented in-depth with SiC device voltage ranges from 1200V to 1700V MOSFETs, and HV 10 kV – 15 kV MOSFETs, JBS diodes, and 15 kV SiC IGBTs, including series connection of devices. The potential and challenges of the HV 10-15 kV devices to enable MV power conversion systems, including MV motor drives, FACTS and MVDC grids will be explored with demonstrated and pilot application examples of SST (Solid State Transformer), MV SiC power converters for grid-tied solar applications, MV motor drives, shipboard power supply applications and MV DC grids. The roadmap of HV SiC power devices in terms of cost targets, module packaging, and reliability qualification of HV SiC devices will be addressed. Advances in medium frequency magnetics for WBG devices based power converters and especially for high power converters, with latest advances in magnetic material qualification and characterization will be included.

Victor Veliadis received the B.S. degree from the National Technical University of Athens Greece in 1990, and the M.S. and Ph.D. degrees in electrical and computer engineering from Johns Hopkins University, Baltimore, MD, USA, in 1992 and 1995, respectively. He is the Executive Director and CTO of PowerAmerica, which is a U.S Department of Energy WBG power electronics Manufacturing Institute. He manages an annual budget in excess of $30 million that he strategically allocates to over 35 industrial and University projects to accelerate WBG manufacturing, workforce development, job creation, and clean energy. He is an ECE Professor at NCSU and an IEEE Fellow and IEEE EDS Distinguished Lecturer. He has 27 issued U.S. patents, 6 book chapters, and over 120 peer-reviewed technical publications. Prior to taking an executive position at Power America in 2016, he spent 21 years in the semiconductor industry where his work included design, fabrication, and testing of 1-12 kV SiC SITs, JFETs, MOSFETs, Thyristors, and JBS and PiN diodes, as well as financial and operations management of a commercial foundry. He has presented several IEEE tutorials in the area of SiC devices for Power Conversion Systems, including at ECCE 2019, 2018, and others.


Subhashish Bhattacharya received his PhD from University of Wisconsin-Madison in 2003. He worked in the FACTS and Power Quality group at Westinghouse R&D Center in Pittsburgh, which later became part of Siemens Power Transmission & Distribution, from 1998 to 2005. He has been involved in several large FACTS projects, including the NY Power Authority (NYPA) 200MVA Convertible Static Compensator project. He joined the Department of ECE at NC State University in 2005, where he is Duke Energy Distinguished Professor, founding faculty member of NSF ERC FREEDM Systems center (www.freedm.ncsu.edu), and DOE initiative on WBG based Manufacturing Innovation Institute – PowerAmerica (www.poweramericainstitute.org). He has authored over 500 peer-reviewed technical articles, 3 book chapters, and has 5 issued patents. York International Corporation (now Johnson Controls) commercialized a part of his PhD research on active power filters for their air-conditioner chiller application. His research interests are Solid-State Transformers, MV power converters, FACTS, Utility applications of power electronics and power quality issues; high-frequency magnetics, active filters, and application of new power semiconductor devices such as SiC for converter topologies. He has presented several IEEE tutorials in the area of SiC based MV Power Conversion Systems, including at ECCE 2019, 2018, 2017, and others


Topic: Packaging/Modules

Speaker: Fang Luo, State University of New York at Stony

Track 2

Topic: GaN Reliability for Power Devices and Applications
Speaker: Sandeep Bahl and Jungwoo Joh, Texas Instruments

Abstract: There has been tremendous progress on GaN reliability in the last few years. As a result, GaN is now reliable and being widely adopted for power management applications. The talk will provide a tutorial on GaN reliability, both from the device and applications-use perspective. We will go over both device and application-use failure modes, summarizing learnings from the literature. We will also explain the gaps in the traditional silicon qualification literature for power management applications, and  how the JEDEC guideline JEP180 assures application reliable GaN. Finally, the topic of surge robustness will be covered. The tutorial will present results from the literature and from our reliability program at TI.

Sandeep Bahl is a Distinguished Member of Technical Staff at Texas Instruments. He has hands-on experience on many aspects of technology development, both in III-V and Si semiconductors. He has done pioneering work in application reliability, leading to both increased market adoption for the GaN industry and reliable GaN products for TI. He co-invented the direct-drive architecture used in TI GaN products and led their reliable release. Sandeep is co-chair of the JEDEC JC70 GaN reliability task group and led the first JEDEC GaN reliability guideline, JEP180. He has also served in committee-chair roles at several IEEE conferences. Sandeep graduated with a PhD in Electrical Engineering from the Massachusetts Institute of Technology.


Jungwoo Joh is the Process Development Manager and currently leading GaN development in the Analog Technology Development unit at Texas Instruments. He has over 15 years of R&D experience in semiconductor reliability physics and process development for high voltage and RF GaN and Si BCD technologies. He received his PhD in Electrical Engineering from MIT in 2009. He has published over 50 journal and conference papers that received 3000 citations and holds 16 US patents.





Topic: Reliability characterization and modeling of GaN-RF devices for upcoming mmWave applications

Abstract: A reliability aware engineering approach for optimization of highly scaled GaN-on-Si RF devices is necessary for enabling the upcoming III-N based mmWave technologies. The GaN-on-Si devices suffer from large variability and time-dependent degradation of device characteristics owing to the enhanced interaction between the 2DEG channel and the large density of defects (barrier/cap interface states, defects in the barrier and buffer layers). This tutorial presents an overview of the important reliability metrics associated with GaN-on-Si devices being developed for integration with standard CMOS-process flows. The impact of gate-field-plate length on the TDDB lifetime of MISHEMT devices is reported. A detailed analysis into the impact of buffer and GaN channel layer thickness on TLM current dispersion is presented. The current progress on the modelling of dynamic-RON in GaN-RF HEMTs is discussed, which is based on the Non-radiative Multiphonon (NMP) theory for describing the charge-trapping kinetics using atomistic physics, as opposed to the SRH-based models. The degradation maps are finally demonstrated to be efficient tools for Design Technology Co-optimization (DTCO).

Vamsi Putcha received his B-Tech degree in Electronics and Communication Engineering from National Institute of Technology (NIT), Kurukshetra, India in 2010, MSc degree in Nanoscience and Nanotechnology from KU Leuven, Belgium in 2014, and PhD degree in Engineering Science (Elec. Engineering) from KU Leuven, Belgium in 2019. His PhD thesis was developed at IMEC, on the topic of “Reliability characterization of gate-stacks for III-V channel MOSFETs”. He is currently working as a researcher at IMEC (Belgium), particularly focusing on characterization and modelling of reliability mechanisms in GaN-RF devices targeted for upcoming 6G/RF/mm-Wave technologies.

Topic: Vertical Devices Technology in Gallium Nitride

Abstract: GaN technology is an ever-expanding topic of research and development, proving its potential to solve several challenges in power conversion that cannot be addressed by Si. For instance, medium voltage (650-900V) devices using the HEMT configuration have been able to reduce form factor at the system level by driving circuits at higher frequencies (100KHz-1MHz) and eliminating heat sinks or reducing cooling requirements. This alone sparked the interest in GaN research to save space, energy and ultimately cost of power conversion. However, in power conversion the demand of high current from a single chip for a rated voltage is a standard need. Particularly when the market is favorable towards electrification of cars and other means of transportations, GaN must expand its scope to provide high power solutions with higher power density compared to Si, and even SiC. Vertical devices have been the choice of power device engineers for economic use of the material and maximum use of its physical properties (which allow highest possible blocking field, field mobility, etc.). GaN vertical devices, therefore, carry all the advantages offered by vertical geometry and are being explored increasingly with emphasis on material and device needs. An overview of the recent achievements in vertical Gallium Nitride (GaN)-based power electronic devices will be presented with reference to a current aperture vertical electron transistor (CAVET), MOSFETs an oxide, GaN interlayer FET (OGFET), Static Induction Transistor (SIT), and high voltage diodes. We have done systematic study of several types of vertical devices and compared their performances.

Prevalent opinion suggests GaN HEMTS are suitable for 650V, while vertical devices are more suited for 1.2kV and up. I will discuss some device fundamentals that include the role of avalanche breakdown, and likelihood of impact ionization of carriers in GaN power devices.

Srabanti Chowdhury (George and Ida Mary Hoover faculty fellow’19, Gabilan fellow ’19, Alfred P. Sloan Fellow in Physics ‘20) is an associate professor of Electrical Engineering (EE), and Senior Fellow at the Precourt Institute for Energy at Stanford University. Her research focuses on wideband gap (WBG) materials and device engineering for energy efficient and compact system architecture for power electronics, and RF applications. Besides Gallium Nitride, her group is exploring Diamond for various electronic applications. She received her B.Tech in India in Radiophysics and Electronics (Univ. of Calcutta) and her M.S and PhD in Electrical Engineering from University of California, Santa Barbara. She received the DARPA Young Faculty Award, NSF CAREER and AFOSR Young Investigator Program (YIP) in 2015. In 2016 she received the Young Scientist award at the International Symposium on Compound Semiconductors (ISCS). She is a senior member of IEEE and NAE Frontiers of Engineering alumni. To date, her work has produced over 6 book chapters, 95 journal papers, 120 conference presentations, and 26 issued patents. She leads the WBG-Lab and affiliated with System-X alliance at Stanford University.


Topic: WBG for Automotive

Abstract: As part of the Electric Drive Technologies Consortium, Oak Ridge National Laboratory (ORNL) is working on increasing the power density of electric traction drives for passenger electric vehicles (EVs) by eight times by 2025 compared to 2015 while reducing the cost and increasing the efficiency. On the power electronics side, their research focuses on components including WBG-based power modules, advanced heat sinks, novel capacitor packaging as they will be applied in the future WBG-based traction inverters with a power density of 100kW/liter or more. The tutorial will start with a general introduction of power electronics needs for passenger EV traction applications and will describe the needs, gaps, and challenges. Then the current component research and the impact of the application will be presented. The tutorial will end with a discussion on next-generation power electronics requirements, gaps, and challenges for commercial vehicle applications.

Burak Ozpineci received the B.Sc. degree in electrical engineering from Orta Dogu Technical University, Ankara, Turkey, in 1994, and the M.Sc. and Ph.D. degrees in electrical engineering from The University of Tennessee, Knoxville, TN, USA, in 1998 and 2002, respectively. In 2001, he joined the Post-Master’s Program with Power Electronics and Electric Machinery Group, Oak Ridge National Laboratory (ORNL), Knoxville, TN, USA. He became a Full Time Research and Development Staff Member in 2002, the Group Leader of the Power and Energy Systems Group in 2008, and Power Electronics and Electric Machinery Group in 2011. Presently, he is serving as the Section Head for the Vehicle and Mobility System Research Section. He also serves as a Joint Faculty with the Bredesen Center, The University of Tennessee. Dr. Ozpineci is a Fellow of IEEE.



Emre Gurpinar (Senior Member, IEEE) received the B.Sc. degree from Istanbul Technical University, Istanbul, Turkey, in 2009, the M.Sc. degree from The University of Manchester, Manchester, U.K., in 2010, and the Ph.D. degree from the University of Nottingham, Nottingham, U.K., in 2017, all in electrical engineering. He was a Visiting Ph.D. Student with the Department of Energy Technology, Aalborg University, Aalborg, Denmark, from August 2015 to October 2015. He was an R&D Power Electronics Engineer with General Electric, Rugby, U.K. In May 2017, he joined the Oak Ridge National Laboratory, Knoxville, TN, USA, where he is currently an R&D Staff with the Electric Drives Research Group. His research interests include wide bandgap power devices, high-frequency converters, packaging and integration of power electronic systems, and electrified transportation. Dr. Gurpinar received the Outstanding Paper Award at the ASME InterPACK Conference in 2019.


Shajjad Chowdhury (Senior Member, IEEE) received the B.Sc. degree in electrical and electronics engineering from the American International University—Bangladesh, Dhaka, Bangladesh, in 2009, the M.Sc. degree in power and control engineering from Liverpool John Moores University, Liverpool, U.K., in 2011, and the Ph.D. degree in electrical and electronics engineering from the University of Nottingham, Nottingham, U.K., in 2016. In January 2017, he joined the Power Electronics, Machines and Control Group, the University of Nottingham, as a Research Fellow. In 2018, he joined Oak Ridge National Laboratory, Oak Ridge, TN, USA, where he is currently working as an R&D associate staff in Electric Drives Research Group. His research interests include multilevel converters, modulation schemes, and high-performance ac drives.