Ralf’s GaN & SiC News (July 28, 2023)
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Ralf’s GaN & SiC News (July 28, 2023)

Welcome to the latest edition of my newsletter on #siliconcarbide and #galliumnitride . If you want to contribute to it, please reach out to me via [email protected]


Gallium Nitride News


Electromagnetic Compliance challenges with fast switching GaN at high power

Rob Gwynne , CEO of QPT , has recorded a series of videos to explain the benefits of the proprietary approach the company is taking to take full advantage of GaN technology.

In the first video, he discusses discusses the EMC challenges of unleashing the full potential of GaN transistors when running them at their maximum switching speeds, at high power.


Effect of plasma process on n-GaN surface probed with electrochemical short loop

Effect of plasma process on n-GaN surface probed with electrochemical short loop
Effect of plasma process on n-GaN surface probed with electrochemical short loop

Plasma etching treatments are important steps in GaN-based devices fabrication but can create defects on GaN surfaces. These surface defects can strongly alter device performances. The main objective of this work of Carole Pernel and her team at CEA-Leti is to characterize the impact of different plasma etching recipes using an innovative electrochemical short loop based on Mott-Schottky (MS) method. The effect of defects has been studied in terms of Fermi Level pinning. Barrier height has been identified as a relevant criterion to describe surface damage induced by plasma treatment.

Probing Conventional LETI plasma etching process with the Mott-Schottky method demonstrates a good reproducibility of the electrochemical data and confirms the reliability of the developed method. Various electrochemical tests conducted on 3 plasma recipes demonstrated that:

  1. the RIE etching is damaging,
  2. the optimized RIE (Steady A) is less damaging than the other RIE (Steady B) and
  3. the RIE associated with ALE process shows the least damaging plasma recipe, as expected.

Carole Pernel , William Berthou , Sidharth Suman , Simon RUEL , Laura V. , Effect of plasma process on n-GaN surface probed with electrochemical short loop , Power Electronic Devices and Components, Volume 6, 2023, 100041, ISSN 2772-3704, https://doi.org/10.1016/j.pedc.2023.100041.

GaN Topics at the PwrSoC workshop September 27-29, 2023

The eighth edition of the biennial International Workshop on Power Supply on Chip (PwrSoC) is scheduled for September 27-29, 2023, to be held at Leibniz Universit?t Hannover , Germany.

One of the sessions is entitled “Wide Band Gap Integration”, chaired by Rinkle Jain from 英特尔 and ke-horng chen from 國立陽明交通大學 . The first presenter is Jan Sonsky of Innoscience , the other one Han Wui T. from Intel.


Fraunhofer IAF: Power electronics for novel heat pumps achieves efficiency of over 99.7%

Ultra-efficient voltage converter for an electrocaloric heat pump with over 99.74% electrical efficiency
Ultra-efficient voltage converter for an electrocaloric heat pump with over 99.74% electrical efficiency

In the ElKaWe project, the Fraunhofer IAF is in charge of developing the drive electronics for electrocaloric heat pumps. For this purpose, the institute is researching devices based on the GaN semiconductosr in order to increase power density and efficiency.

For the first time, the researchers have now developed and optimized power electronics specifically for electrocalorics. They have succeeded in implementing an ultra-efficient circuit topology for voltage converters based on GaN transistors, achieving an electrical efficiency of 99.74% in the electrical power path. The GaN-based multilevel DC-DC converter thus sets global standards and far exceeds the previous state of research of less than 90% conversion efficiency for electrical control of these novel heat pumps.

“Our ultra-efficient power electronics make it realistic for the first time to achieve well over 50% of the maximum theoretical coefficient of performance with electrocaloric heat pumps, even at the system level,” says Dr. Stefan M?nch, Fraunhofer IAF.
Stefan M?nch , Richard Reiner , Kareem Mansour, Patrick Waltereit , Michael Basler , Rüdiger Quay , Christian Molin , Sylvia E. Gebhardt , David Bach , Roland Binninger , Kilian Bartholomé , "A 99.74% Efficient Capacitor-Charging Converter using Partial Power Processing for Electrocalorics ," in IEEE Journal of Emerging and Selected Topics in Power Electronics, doi: 10.1109/JESTPE.2023.3270375.

Analytical Model of Center Potential in GaN Vertical Junctionless Power Fin-MOSFETs

Schematic of the GaN VJ power Fin-MOSFET analyzed in this work.
Schematic of the GaN VJ power Fin-MOSFET analyzed in this work.

In this work, Jyoti Patel and her team at the Indian Institute of Technology, Roorkee present an analytical model for fast optimization of gallium nitride vertical junctionless (VJ) power Fin-MOSFET device design. The derived model faithfully captures the electrostatic behavior of the VJ Fin-MOSFET at high bias conditions. Consequently, power device operation parameter of interest such as maximum source-to-drain potential barrier (?(b,max)) and its dependence on large drain bias is well-predicted. Moreover, using the derived analytical model, we show that the distance between gate and source can be tuned to improve ?(b,max) for countering the drain-induced barrier lowering (DIBL) effect. The analytical model derived in this work is generic in nature, and it can be adopted to optimize any ultrawide bandgap semiconductor-based VJ power Fin-MOSFET device design.

Jyoti Patel, Tanmoy Pramanik and Biplab Sarkar , "Analytical Model of Center Potential in GaN Vertical Junctionless Power Fin-MOSFETs for Fast Device-Design Optimization ," in IEEE Transactions on Electron Devices, doi: 10.1109/TED.2023.3293067.

Silicon Carbide News


China’s SiC industry to seize M&A trend and move toward 200mm production

The growing importance of the SiC sector will continue to drive M&A activities, with three to four major M&A cases expected to take place each year in the upcoming three to five years, according to sources. Despite China's ambition to leapfrog, the local SiC industry remains a late comer, and there has been a limited number of large-scale M&A activities in this sector, though the trend will inevitably pick up, DIGITIMES Asia reports.

As Gilbert (Xiaoyang) Zhou 周晓阳 , President of China-based IDM AccoPower, pointed out to Chinese media Ijiwei, the SiC racetrack in China is already too crowded, and some players will be eliminated, with M&A and restructuring an inevitable development.

To be competitive against international peers who can cover multiple customer needs through different SiC production equipment, China-based SiC players also have to seize the M&A trend to realize horizontal integration, especially when the majority of them can only cover one type of demand.

Meanwhile, approximately 80% of China’s large-scale SiC production is based on 150mm wafers, DRAMeXchange - DRAM and NAND Flash Research reported, and the realization of large-scale production on 200mm wafers has been another focus of China’s SiC industry. According to TrendForce Corporation , the yield of China’s 150mm SiC substrate is 40%, compared to the 60-70% of international players. TrendForce indicates that there are 10 China-based enterprises and institutions involved in the R&D of 200mm substrates, including SemiSiC Crystal, SICC and TankeBlue Semiconductor. Notably, SICC and TankeBlue have recently partnered with 英飞凌 . Both companies will reportedly facilitate Infineon’s transition towards 200mm wafers.


Qorvo's new release of QSPICE also for SiC devices

Qorvo QSPICE to Revolutionize Circuit Simulation for Power and Analog Designer

Qorvo, Inc. announced the release of QSPICE, a new generation of circuit simulation software that should provide power and analog designers significantly higher levels of design productivity through improved simulation speed, functionality and reliability – also for the company’s SiC devices from Qorvo Power .

QSPICE is available free of charge and offers numerous enhancements over legacy analog modeling tools.

“In the past, power designers relied on analog circuits and silicon power switches. Today, digital control and compound semiconductors are common elements of advanced power designs. Whether an engineer is developing AI algorithms for EV battery charging, optimizing a Qorvo pulsed-radar power supply or evaluating the newest silicon carbide FETs, QSPICE is the perfect platform for innovation,” Jeff Strang , GM for Qorvo’s Power Management business.

Miscellaneous News


PowerAmerica: 2023 Wide Bandgap Summer Workshop

PowerAmerica invites to its annual Summer Workshop, August 8-10, 2023, on 美国北卡罗莱纳州立大学 ’s Centennial Campus in Raleigh, NC. Participants can expect great networking and presentations on the latest in the business and technology of silicon carbide and gallium nitride power semiconductors and applications.

Keynote presentations will be delivered by Clayton Pillion , VP Silicon Carbide Business Unit at Microchip Technology Inc. , and Jeffrey Perkins from Yole Group .

The workshop includes:

  • WBG Tutorials by Sei-Hyung Ryu ( Wolfspeed ) and Roger Brewer ( Lockheed Martin )
  • Reports on 10 SiC and GaN PowerAmerica member-funded projects
  • Update on SiC and GaN market trends
  • Roadmapping future PowerAmerica initiatives

A draft agenda can be found here .


Webinar: How to Perform Double Pulse Testing on GaN and SiC Devices

On September 6, 2023, at 11 AM Pacific and 2 PM Eastern respectively, William B Kaunds , Product Marketing Manager at Teledyne LeCroy will show how to perform the double pulse test safely, and capture and characterize a GaN or SiC power semiconductor device’s dynamic response.

Topics to be covered in this webinar:

  • Double Pulse Test (DPT) basics
  • Test instrumentation needs
  • Safety issues and how to overcome them
  • The importance of probe deskew
  • How to calculate turn on/off delays, switching losses, etc.

Learn more about various safety measures that need to be addressed before making measurements and what to infer from the captured waveforms.

Can't attend live? Register anyway and we will send you the recording afterwards.


Counterfeit Chips: IGBTs instead of SiC MOSFETs inside

X-ray image of integrated devices, the second from the right has no chip (Image Credit: Creative Electron, Inc)
X-ray image of integrated devices, the second from the right has no chip (Image Credit: Creative Electron, Inc)

In a LinkedIn article, Mohanad Zaki wants to raise awareness on the topic of #counterfeitchips #fakechips , as the semiconductor devices shortage during the #COVID pandemic might have pushed system builders to use grey markt chips (non-official distribution channels).

One of the issues he highlights are “different chips” which are built and labelled as if it came from a reputable semiconductor manufacturer e.g., an end of life IGBT instead of SiC MOSFET in TO247 package. The IGBT might still electrically have the same blocking voltage but a different gate capacitance and different switching characteristics. This is a risk for humans as well as for business.

At the end of his article, Zaki describes some of the methods to screen chips to find counterfeit products.


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