System-Level Impact of WBG Power Devices at 2016 IEDM

October 24, 2016 by Jeff Shepard

The IEEE's annual International Electron Devices Meeting (IEDM) is the world's largest and most influential forum for technologists to unveil breakthroughs in transistors and related micro/nanoelectronics devices. The 62nd annual meeting, to be held at the Hilton San Francisco Union Square Hotel from December 3 - 7, 2016, will include a session (Session #20) on System-Level Impact of Power Devices that will consider the impact of GaN and SiC power devices on system designs.

The use of GaN and SiC has made it possible to expand the use of electronics at very high voltages, temperatures and power levels compared to existing silicon-based power devices, revolutionizing the way power is delivered and managed. This Special Focus Session will describe recent advances in wide-bandgap power devices, show how they are transforming power delivery systems, benchmark material characteristics and reliability, and consider future directions.

Yesterday, PowerPulse reviewed three of the papers in this important technical session: “Wide Bandgap (WBG) Power Devices and Their Impacts On Power Delivery Systems,” by Alex Huang, North Carolina State University; “Si, SiC and GaN Power Devices: An Unbiased View on Key Performance Indicators,” by G. Deboy et al, Infineon/ETH-Zurich; “System-Level Impact of GaN Power Devices in Server Architectures,” by A. Lidow et al, Efficient Power Conversion Corp.

In today’s concluding article, PowerPulse provides overviews of the remaining three papers in this session:

“GaN-based Semiconductor Devices for Future Power Switching Systems,” by H. Ishida et at, Panasonic GaN-based natural superjunction diodes and Gate Injection Transistors (GITs) with p-type gate on AlGaN/GaN hetero structure are promising power devices with lower on-state resistance and higher breakdown voltage for power switching applications. In this paper, the current status of the devices for integrated circuits and their application to power switching systems are reviewed, after explaining the basic technologies for decreasing on-resistance, increasing breakdown voltage, and suppressing current collapse. In addition, a solution to increase switching frequency of GITs for smaller system size is described. The effects of integrated circuit of DC-DC converter consisted of gate driver, high-side GIT and low-side GIT with short gate length are also examined. Higher switching frequency requires lower parasitic inductance to achieve precise waveform without overshoot. Therefore, integration of the devices is inevitable to control the waveform precisely.

“Application Reliability Validation of GaN Power Devices,” by S. Bahl et al, Texas Instruments Standard qualification methodology or “qual” does not specify product-level testing due to the diverse range of products and use conditions, a limited ability for system-level acceleration, and complication from system-level failures. This is a concern for emerging power-management technologies, since the fundamental switching transitions are not covered. The paper will show that hard-switching with the well-known double-pulse tester is predictive of device performance under system-level testing. This simplifies the problem of product reliability testing to one of a device and a tester. It enables detection devices that pass qual but perform poorly in application. As a result, devices pass qual and perform well in application.

“Horizon Beyond Ideal Power Devices,” by H. Ohashi, NPERC-J (Japan’s New-Generation Power Electronics & System Research Consortium) This paper presents an inconvenient truth that is confronting us when we investigate possibility of the future power electronics and power devices. It is that efficiency of power convertor is approaching to 100 percent. Change of target in power electronics progress is discussed from efficiency to prevalence of the efficient use of electrical energy. Standing on this viewpoint, new concept, nega-watt cost is proposed. In term of the nega-watt cost, role of advanced power devices are discussed looking at horizon beyond ideal power devices in efficiency.

According to the author of this final paper in the session: A second challenge is to realize an energy internet as a service domain by bringing together distributed energy network and digital network through integration of the semiconductor domain and functional domain. Energy internet domain is made up mainly of the semiconductor domain. The semiconductor domain and service domain will be connected by the functional domain which will consist of integrated power converters, solid state transformers, energy routers, intelligent breakers, data centers, base stations, Wi-Fi, and so on. In the semiconductor domain, highly seamless system integration of sensor, processor, memory, communication and power device in the level of on-chip and in-package will develop in the future. At same time, software, protocol and novel power network theory will be essential for system integration realization as cluster of semiconductor group, as well as basic research of advance material and fabrication technology. Collaboration in making technology roadmap toward the future horizon is needed.