Ralf’s GaN & SiC News (February 13, 2025)
Welcome to the latest edition of my newsletter on silicon carbide, gallium nitride, and other wide bandgap semiconductor materials. If you want to get covered, please reach out to me via [email protected]
Content
Breaking News: Power Integrations CEO Balu Balakrishnan to retire, and Gregg Lowe named to its Board of Directors
Power Integrations announced that Balu Balakrishnan , the company’s CEO since 2002, will retire from that role once a successor is in place. The company’s board of directors has retained an executive search firm to assist in identifying its next CEO; both internal and external candidates will be considered. Mr. Balakrishnan, 70, intends to serve as executive chairman of the company’s board for as long as is needed to ensure a smooth transition to his successor and is expected to remain on the board of directors thereafter.
I met with Balu many times, but my favorite memory was my interview with him at APEC 2016 when I learned about his “Margarita moment” regarding InnoSwitch. Here is an excerpt from that interview:
“ Mike Matthews , our head of engineering, and I decided to take a week off to think about what we could do next. Since the company was founded, we have focused on the primary side of power supplies, and we have virtually integrated everything possible there. The only things left were the large passive components such as the DC link capacitors, the transformer, and the EMC components. So how could we take the next step in terms of integration?
The obvious thing was to integrate something on the secondary side. Several others had already tried this and failed. But it was really the only thing left. For a whole week, we racked our brains in our hotel room on the Cayman Islands, trying to figure out how to do it. In any case, we couldn't think of a good way to integrate the secondary side cost-effectively. Therefore, we gave up.
On the day of departure, we checked out of the hotel at noon. Since our flight didn't leave until 4 p.m., we made ourselves comfortable in the hotel lobby. “Maybe we're just thinking too hard about this. Let's just relax a little. Maybe then we'll get an idea,” I said. So we ordered some Margaritas.
And while we were drinking our Margaritas, I said to Mike, ‘What do you think, could this work?’ He said, ‘Hm, maybe it could.’ Mike is very familiar with magnetic components because he comes from the field of drive technology; I'm just a chip designer. So we did some rough calculations: Would we get enough energy across the isolation distance? Would the isolation distance be sufficient to meet the safety standards? And so we went on the internet to find out what safety requirements had to be met. At the end of the day, we were 80 to 90 percent sure: it's feasible!
Back in the office, Mike went straight to the lab to do some tests. He wound wires around the lead frame to find out what the coupling factor was. And since everything is on the one lead frame, it is very cost-efficient to manufacture.”
Gregg Lowe will join the company’s board of directors on February 15, 2025. From 2017 until 2024, Mr. Lowe was CEO of Wolfspeed , where he led the company’s transition to a pure-play manufacturer of silicon-carbide solutions for high-power applications. Previously, he was CEO of Freescale Semiconductor from 2012 until its 2015 merger with 恩智浦半导体 . Earlier, he had a 27-year career at 德州仪器 , serving in a succession of leadership roles across field sales, automotive sales, marketing, and integrated circuits, culminating in the role of senior vice president and manager of the company’s analog business, where he helped direct the acquisition of National Semiconductor.
Miscellaneous News
Infineon Wide-Bandgap Developer Forum
For many years now, 英飞凌 ’ Wide-Bandgap Developer Forum has been an event, bringing together experts from the fields of SiC and GaN. 11 March 2025 will mark the latest chapter in this exclusive event series. Infineon will be broadcasting specialist presentations live from its studio in Munich.
The keynote speech by the Division Presidents Dr. Peter Wawer (Green Industrial Power) and Adam White (Power & Sensor Systems) will kick off this year’s event and provide inspiring insights into market developments and Infineon’s WBG strategy. The morning will be targeted to silicon carbide, the afternoon to gallium nitride and other topics.
One highlight for me will be the presentation “GaN Monolithic Bi-directional Switch - A New Paradigm in Power Electronics” by Kenneth Leong.
Monolithic on-chip integration of micro-thin film thermocouples on multi-finger gallium oxide MOSFETs
Multi-finger (MF) Ga?O? MOSFETs, designed to enhance current handling and thermal management, experience significant self-heating effects that can lead to localized hotspots, thermal runaway, and reduced device reliability. Accurate thermal characterization is therefore critical to ensure the reliable operation and longevity of such devices. Conventional methods, such as thermos-reflectance imaging, Raman thermometry, and infrared thermography, are limited by complex setups, slow response times, resolution constraints, and cost, making them less practical for real-time, on-chip applications. On-chip thermal characterization directly at the active regions of the device provides an unparalleled opportunity to overcome these limitations by capturing localized temperature variations during operation.
In this study, researchers from KAUST (King Abdullah University of Science and Technology) demonstrate the integration of micro-thin film thermocouples (micro-TFTCs) onto multi-finger Ga?O? MOSFETs for precise, real-time, and localized thermal monitoring. The sensors captured temperature variations across different gate fingers, with the measured maximum channel temperature reaching +40.5?°C under peak power dissipation. Predicted thermal behavior under high power densities shows temperatures rising to approximately +80?°C at 5?W/mm2, illustrating the thermal challenges faced by Ga?O? devices.
This work demonstrates that micro-TFTCs are compatible with complex device architectures and highly effective for localized thermal characterization, making them a promising tool for improving the thermal management and reliability of Ga?O?-based power electronics.
Hassan Irshad Bhatti , Ganesh Mainali , Xiaohang Li ; Monolithic on-chip integration of micro-thin film thermocouples on multifinger gallium oxide MOSFETs. Appl. Phys. Lett. 27 January 2025; 126 (4): 043511. https://doi.org/10.1063/5.0250985
Webinar with Christina DiMarino: Advanced packaging and integration of WBG power semiconductors
This is a special research webinar by Christina DiMarino , Assistant Professor at the Center for Power Electronics Systems, Virginia Tech and Virginia Tech ’s Department of Electrical and Computer Engineering. In her presentation, Dr. DiMarino discusses the world-class CPES facilities and the expansive capabilities they enable for innovative power electronics packaging solutions.
WBG power semiconductors, such as SiC and GaN, enable power electronics systems that meet these demands due to their faster switching, lower losses, and higher voltage ratings than conventional silicon power devices. However, new approaches to the packaging and integration of WBG devices are essential to unleashing their full potential. This talk delves into the evolving landscape of WBG power semiconductor packaging and integration, and the unique multidisciplinary packaging challenges posed by these devices. Dr. DiMarino discusses CPES’ state-of-the-art packaging laboratories and instrumentation, innovative packaging solutions from select projects, and future research directions.
Evaluation of the bonding strength of die attachment techniques for gallium oxide power devices
The integration of gallium oxide (Ga?O?) in electronic packaging has gained significant attention in recent research due to its promising properties. Despite this growing interest, technology remains predominantly at the academic research stage, largely due to a lack of comprehensive data on the packaging process. Die attachment is a crucial factor for establishing functional and reliable semiconductor packages.
This study from researchers at the University of Arkansas sheds light on various factors that can affect the bonding strength of Ga?O? chips on conventional direct bonded copper (DBC). Several samples were prepared by attaching Ga?O? and Si chips onto gold-plated DBCs using various die attachment materials and methods. The bonding strength of each sample was evaluated through shear testing.
The results indicated that surface roughness, die attachment method, die attachment material, metallization, and chip size significantly influenced the bonding strength.
Tanzila Akter , Mohammad Dehan Rahman, Yuyang Wang, Yuxiang Chen , Alan Mantooth , and Xiaoqing Song , "Evaluation of the Bonding Strength of Die Attachment Techniques for Gallium Oxide Power Devices," 2024 IEEE 11th Workshop on Wide Bandgap Power Devices & Applications (WiPDA), Dayton, OH, USA, 2024, pp. 1-5, doi: 10.1109/WiPDA62103.2024.10773288.
Navitas’ GaNFast and GeneSiC devices power Dell’s family of AI notebooks
Navitas Semiconductor announced its adoption of GaN and SiC technologies into the Dell Technologies ' family of notebook adapters, from 60 W to 360 W. Dell’s latest line-up of AI notebooks includes Neural Processor Units (NPUs), which are dedicated AI engines, to manage sustained AI and AI offload. This builds on Dell’s portfolio as the broadest GaN adapter offering for notebooks in the industry.
The new adapters will also help Dell achieve its advanced sustainability goals, with a focus on CO? reduction and energy reduction. The adapter cases require up to 50% less plastic and are made with post-recycled materials, significantly reducing energy waste, and improving resource utilization. Navitas’ GaNFast and GeneSiC technologies increase the level of system integration and switching frequency, which reduces the number of components, as well as the size, resulting in a ‘dematerialization’ that lowers carbon footprint throughout the production, packaging, and logistics processes. Each GaNFast power IC shipped saves 4 kg CO2 and every SiC MOSFET shipped saves 25 kg CO? vs. legacy silicon power chips.
“Since Dell’s first GaN adapter was enabled by Navitas back in 2020, we’ve worked closely with Dell engineering to further improve charging speed, efficiency, size, weight, and now environmental footprint. Our clients achieve a win-win for both the market and environment by deploying Navitas GaNFast power ICs and GeneSiC power devices,” said Gene Sheridan, CEO and co-founder of Navitas.
Conventional, wide-bandgap, and hybrid power converters: A comprehensive review
This review from researchers at the Sardar Vallabhbhai National Institute of Technology, Surat and the National Institute of Technology Karnataka delves into cutting-edge WBG technology, a third-generation switching device, exploring its fundamental properties and system-level applications. Emphasizing SiC and GaN materials, the review highlights their superior energy efficiency in power electronic converters compared to traditional silicon (Si) materials.
WBG-based converters achieve higher efficiency and reduce energy losses as compared to Si-based converters. These devices operate effectively at higher switching frequencies and reduce passive component size in direct current (DC) - alternating current (AC) applications at higher cost. Thereby, this study identifies hybrid converters combining Si and WBG switches as cost-effective solutions, achieving efficiency gains of higher percentages over fully Si-based designs.
The review presents a parametric comparison among traditional, fully WBG-based, and hybrid converters, examining various aspects such as switching frequency, blocking voltages, losses, efficiency, reliability, cost, thermal constraints, and device count which remain essential for the broader adoption in various applications.
Anvi N. Suthar, J. Venkataramanaiah, Y. Suresh, Conventional, wide-bandgap, and hybrid power converters: A comprehensive review, Renewable and Sustainable Energy Reviews, Volume 213, 2025, 115419, ISSN 1364-0321, https://doi.org/10.1016/j.rser.2025.115419.
Job Exchange
University of Bristol: Postdoctoral researcher in Gallium Oxide device processing and characterization
The 英国布里斯托大学 invites applications for the role of Postdoctoral Researcher position at the Centre for Device Thermography and Reliability (CDTR), led by Professor Martin Kuball , to provide leading contributions in the field of Gallium Oxide device processing, device modeling, and characterization. This is a one-year position, initially.
You will conduct research to develop advanced ultrawide bandgap semiconductor device technology and their understanding. Responsibilities include the processing of high-voltage power devices, in particular Ga?O?, conducting electrical characterization and testing of the processed devices, and performing simulations of targeted device structures.
Gallium Nitride News
Changan launches GaN-based OBC using Navitas technology
长安汽车 has introduced what it claims to be the world’s first commercial GaN-based on-board charger (OBC) technology platform, integrated into the newly launched Qiyuan E07 electric vehicle. The Chinese automaker, one of the country’s oldest, has implemented high-power GaN devices from Navitas Semiconductor to achieve increased power density and efficiency in the vehicle’s charging system.
领英推荐
The Changan Qiyuan E07 is an original electric SUV pickup hybrid. It runs single- and dual-motor systems driven by ternary lithium batteries. Whereas the dual-motor version offers 440 kW and reaches 210 km/h, the single-motor variant delivers 252 kW.
Changan claims that the GaN-based OBC runs with an efficiency of 96% in charging and discharging and has a power density of 6 kW per liter. The company also projects that higher efficiency might prolong the lifetime driving range of the car by about 10,000 kilometers. Changan also emphasizes as another important factor possible cost reductions. According to the business, users of the car could enjoy a 15–20% decrease in charging costs during its lifetime when compared to standard OBC solutions.
Nimy collaborating with M2i to secure gallium supply for US government and defense industry
The Australian mining firm Nimy Resources has executed a non-binding collaboration agreement with M2i Global, Inc. (OTCQB:MTWO) (Minerals Metals Initiatives) to assure a supply of gallium in support of the United States Department of Defense (DOD).
M2i specializes in developing and executing a complete global value supply chain of critical minerals for US national defense and economic growth and security, as well as that of US free-trade partners. Its subsidiaries, US Minerals Inc and Metals Corp are engineering, research, and services firms that bring together people, technology, and solutions from across Government, business, not-for-profits, and academia to provide access and availability to critical minerals and metals for defense and economic security.
Through its Manufacturing Capability Expansion and Investment Prioritization Office, the US DOD is keen to secure a reliable, sustainable supply of gallium materials that can be used in support of the US Government including, but not limited to, the production of semiconductors, radar, and aerospace technologies.
Monolithic integrated micro-thin-film thermocouples for on-chip temperature measurement of GaN HEMTs
GaN devices could encounter self-heating effects at high power, causing current collapse and performance degradation. Accurate temperature monitoring in GaN devices is essential for maintaining performance and avoiding failures. Micro-thin-film thermocouples (micro-TFTCs) offer a solution with their high-resolution and direct temperature measurements. These thermocouples, integrated onto device surfaces, bypass the limitations of other methods.
In this work, researchers at KAUST (King Abdullah University of Science and Technology) demonstrate the monolithic integration of micro-TFTCs into GaN HEMTs, using a platinum-chromium junction with a sensitivity of 19.23 ± 0.405 μV/K. This enabled precise monitoring of GaN HEMT channel (channel width =200 μm) temperatures, with a measured temperature of 68.54 °C ± 0.16 K at a power density of 5.72 W/mm, highlighting the effectiveness of this technique in the thermal characterization of semiconductor devices.
Hassan Irshad Bhatti , Saravanan Yuvaraja, PhD , chuanju wang , Xiao Tang , Xiaohang Li , "Monolithic Integrated Micro-Thin-Film Thermocouples for On-Chip Temperature Measurement of GaN HEMTs," in IEEE Transactions on Electron Devices, vol. 71, no. 12, pp. 7734-7739, Dec. 2024, doi: 10.1109/TED.2024.3487815.
Webinar: Enabling high-efficiency, reliable GaN designs with an innovative Active Clamp Flyback controller
As the demand for smaller, more energy-efficient power solutions grows, engineers are increasingly turning to GaN technology to unlock higher performance. In this webinar, giovanni tomasello will explore how 意法半导体 ' Active Clamp Flyback (ACF) controller, combined with GaN SiP (MasterGaN) technology, can deliver superior efficiency, greater power density, and improved thermal performance—key factors for next-generation applications like laptop and smartphone chargers, adapters, and high-power-density switched-mode power supplies (SMPS).
High-voltage GaN HEMT with self-biased P-GaN VLD layer for improved breakdown voltage and figure of merit
In this article, researchers from the 电子科技大学 and Leshan Share Electronic propose a novel high-voltage GaN HEMT device with a self-biased multiple-stepped P-GaN cap variation lateral doping (VLD) layer. The stepped P-GaN VLD layer is self-biased with a voltage of ～5.7 V, preventing depletion of the 2D electron gas in the on-state and maintaining normal current flow. Moreover, it optimizes the surface electric field and increases the breakdown voltage (BV) of the device. Meanwhile, the ohmic contact is formed on the P-GaN layer, hole injection effect occurs in the on-state of the device, which suppresses the current collapse effect.
The simulation results show that the BV and the specific on-resistance (R_on,sp) of the proposed and conventional devices are 1650 V and 3.1 mΩ?cm2, and 650 V and 2.7 mΩ?cm2, respectively. The figures of merit (FOM) of the two devices are 0.878 GW/cm2 and 0.156 GW/cm2, which is increased by 462.8 %. The proposed GaN HEMT elevates the BV to over 1200 V-class, along with improved immunity to current collapse.
Moufu Kong, Ning Yu, Yaowen Zhang, Zeyu Cheng, Bingke Zhang, Bo Yi, Hongqiang Yang, High-voltage GaN HEMT with self-biased P-GaN VLD layer for improved breakdown voltage and figure of merit, Microelectronics Journal, 156, 106536, 2025 DOI https://doi.org/10.1016/j.mejo.2024.106536
Feasibility analysis of parameter-based temperature estimation of pGaN HEMTs under consideration of charge carrier trapping
In this paper, researchers from ZF 集团 and Technische Universit?t Dortmund investigate several typical temperature-sensitive electrical parameters regarding their applicability in Schottky-contact and Gate-Injection GaN HEMTs. In addition, the effect of charge carrier trapping on the temperature behavior of the threshold voltage and gate current is analyzed.
It is found that the drain-source on-resistance, the drain-source capacitance, and the transconductance can all be exploited for temperature estimation. On the other hand, shifting of the threshold voltage due to gate voltage stresses obfuscates any shifting caused by temperature changes in Schottky-contact devices and the ohmic-contact devices to a smaller degree. The gate current of the Schottky-contact device is also stress-dependent around the threshold voltage but stabilizes at higher gate-source voltage values. In contrast, the gate current of the ohmic-contact device is unaffected by gate stress in the transistor on-state.
Jorge Alejandro Pérez Pérez , Martin Pfost . Feasibility Analysis of Parameter-Based Temperature Estimation of pGaN Power HEMTs Under Consideration of Charge Carrier Trapping. TechRxiv. January 21, 2025. DOI: 10.36227/techrxiv.173747480.09023900/v1
Silicon Carbide News
Video interview: Evaluating the performance of 1200-V SiC devices
Amine Allouche , Senior Analyst at Yole Group , recently spoke with Phil Alsop from Power Electronics World Magazine & PE International Conference to explore Yole Group’s latest performance analysis reports.
In the discussion, Amine highlights the collaboration between Yole Group and SERMA Technologies , which has led to two groundbreaking reports on SiC MOSFET performance. The first report, SiC MOSFET Discretes Performance Comparison Analysis 2024 Vol 1, delves into discrete 1200V SiC MOSFETs. The second report, SiC Modules Performance Analysis 2024 Vol 1, focuses on the performance of SiC power modules. Together, these reports offer an exhaustive comparison and in-depth analysis of SiC devices, providing essential insights for engineers, designers, and decision-makers in the semiconductor and power electronics industries.
Wine Down Friday with Wolfspeed’s Elif Balkas
On Wine Down Friday, Maurizio Di Paolo Emilio was excited to welcome Elif Balkas , CTO of Wolfspeed , a visionary leader shaping the future of wide-bandgap semiconductors. Her journey, inspired by a love for materials science and a natural curiosity about quantum-level phenomena, has driven groundbreaking advancements in semiconductor technologies.
Elif spoke about the value of diversity and inclusion in the tech sector, her role in Wolfspeed’s Women’s Initiative, and her most recent appointment to the Industrial Advisory Committee of the U.S. Department of Commerce . She also provided a window into her personal life, interests, and the future direction of silicon carbide technology. Additionally, she expressed admiration for Lisa Su , CEO of AMD , highlighting the impact of combining technical vision with leadership.
Podcast: SiC reliability testing
In another episode of podcast4engineers, 英飞凌 addresses another crucial question: How can they ensure SiC chips work reliably for decades without spending decades testing them? This podcast dives deep into SiC reliability testing with the renowned expert guest, Paul Salmen .
Salmen, a leading authority in SiC technology, shares his knowledge and expertise on the reliability testing of CoolSiC devices. With years of hands-on experience, Paul provides invaluable insights into the methodologies and best practices for ensuring the long-term reliability of SiC chips.
Topics which were discussed:
Wolfspeed nears completion of its $5B Chatham County factory
Wolfspeed hopes to take full occupancy of its under-construction factory in Chatham County in March and begin production in June, the company told Axios . This $5 billion Siler City plant, which will make silicon carbide crystals used in electric vehicles, is part of a wave of large expansions that North Carolina landed in the past four years. Along with Toyota Motor Corporation in Randolph County and FUJIFILM Diosynth Biotechnologies in Holly Springs, Wolfspeed's facility is one of the few that is nearing completion.
State and local governments have pledged more than $700 million in incentives for the project, some of which has already been used to prepare the site and others that will only be awarded if the company reaches hiring targets set by the state.
The site could ultimately employ around 1,800 workers in the coming years, and during peak construction around 3,800 people were on the site, according to Chris McCann , VP of global project management at Wolfspeed.
At the same time, the company remains in negotiations with the incoming Trump Administration to finalize a $750 million CHIPS Act grant for boosting semiconductor manufacturing in the U.S., according to a company spokesperson. The funding will support the Siler City plant's expansion. Trump has criticized the CHIPS Act in the past, leading some to worry its future could be in doubt, Fox Business reported. Trump's incoming Commerce Secretary, Howard Lutnick, however, has referred to the CHIPS Act as an "excellent down payment," Bloomberg News reported.
Research on anti-single event ability and reinforcement method of SiC MOSFET
High-voltage SiC MOSFETs are limited by their ability to resist single-event effects (SEE). Therefore, it is necessary to study their ability to resist SEE and form an effective reinforcement method. In this paper from researchers at the Shanghai Institute of Aerospace Technical Foundation, it is studied how the influence of device structure on the anti-single event ability of SiC MOSFET from the irradiation experiment, and the safe working area of single event leakage degradation of the device is examined. It is found that the width of JFET and P-type ohmic contact interval both affect the SEE of the device.
The SEE mechanism of the device is analyzed based on the experimental results. The failure caused by local electrothermal stress concentration is confirmed. Because of this mechanism, the reinforced structure is designed with a SiO? barrier layer added in the single event sensitive area, the electrical stress is effectively alleviated, and the peak drain current is reduced by about 18%.
Linsheng Qin, Bo Wang, Yuhan Huang, Lindong Ma, Yuan Liu, Anan Ju and Kunshu Wang, J. Phys.: Conf. Ser. 2851 012016
Infineon releases industrial CoolSiC MOSFETs 650 V G2 in Q-DPAK and TOLL packages
英飞凌 is expanding its portfolio of discrete CoolSiC MOSFETs 650 V with two new product families housed in Q-DPAK and TOLL packages. These diverse product families, with top- and bottom-side cooling, are based on the CoolSiC Generation 2 (G2) technology and offer significantly improved performance, reliability, and ease of use. The product families target high- and medium-power switched-mode power supplies (SMPS) including AI servers, renewable energy, chargers for electric vehicles, e-mobility and humanoid robots, televisions, drives, and solid-state circuit breakers. The devices are now available in R_DS(on) from 10 to 60 m?, while the Q-DPAK variant is available in 7, 10, 15, and 20 m?.
B.S. in Computer Engineering, CS + Math minor | Focused on Mixed Signal IC design | Lead Reflow Engineer at TERAM
2 周Absolutely excellent, thank you for the details in wide bandgap semiconductor news and research. Super nice being able to find a lot of the links to research papers in one place.
Associate Professor, Advanced Semiconductor Lab at KAUST | (Ultra)wide Bandgap Semiconductor and 3D Stacking
2 周Thank you Ralf Higgelke for highlighting two of our papers published in APL and IEEE TED on monolithic integration of micro thermal couple on GaN and Ga2O3 power transistors.