Below is a summary of the US Power Electronics Technology and Manufacturing Roadmap, developed by the US Power Electronics Industry Collaborative (PEIC) and submitted as the final report to NIST for PEIC’s 24-month project entitled “Strengthening the Domestic Power Electronics Ecosystem,” which was funded by the US Department of Commerce under their Advanced Manufacturing Technology AMTech Program. The report’s lead authors are Keith Evans, president of PEIC, and Dave Hurst, formerly a market analysis expert at NextEnergy.
Recent advances in power semiconductor technology have opened up new opportunities for innovation in power electronics. Market and regulatory conditions have created global demand for power electronics systems that take advantage of new semiconductor technologies to enable higher efficiency devices that operate at higher temperatures, higher frequencies, and higher voltages in smaller packages and lower overall system cost. In order to meet these demands at scale, several technological and manufacturing challenges still need to be overcome. This roadmap provides an overview of these challenges, the current state of the art, and emerging solutions to achieve these benefits. Emphasis is placed on understanding trends including inter-dependencies in semiconductors, capacitors, magnetics, and packaging technology. Using this information, this roadmap also presents key strategic recommendations for the U.S. to take advantage of these technological trends.
Wide bandgap (WBG) semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) offer the potential for smaller, more robust, higher power devices that switch faster and are more energy efficient than silicon (Si) based devices. The development of WBG semiconductor devices is a major component of the global innovation race in power electronics. WBG semiconductor devices, especially SiC and GaN-on-Si devices, are beginning to penetrate the market, although Si devices continue to dominate the industry.
The US WBG semiconductor device manufacturing supply chain is more developed in SiC device technology, while GaN-on-Si devices tend to be manufactured in Asian foundries, leveraging the massive Si device foundry infrastructure there.
Additionally, next generation WBG semiconductors like bulk GaN and so-called ultra-wide bandgap (UWBG) semiconductors like gallium oxide (Ga2O3), aluminum gallium nitride (AlGaN) and diamond are in aggressive development as they promise additional performance advantages over SiC and GaN-on-Si.
Semiconductors are just one part of the overall power electronics system. While WBG and UWBG semiconductors are capable of operating at higher voltages and temperatures, today’s capacitors are not. Similarly, while WBG semiconductors are capable of operating at higher frequencies, today’s soft magnetics are not. Additionally, advances in packaging and thermal management are required before WBG semiconductors can be fully leveraged. The implication of improved semiconductor performance has ripple effects throughout the supply chain for power electronics as suggested in Figure 1.
The components that support the overall power electronics systems, including capacitors, magnetic components, and packaging technologies are being pushed to match the new semiconductor performance levels, which in turn is creating market conundrums that are hampering growth of advanced semiconductors.
Current capacitor technologies struggle to match the high temperature performance needs, as existing capacitor technologies are limited by the properties of the dielectric used. Consequently, this presents a global innovation whitespace for the discovery and development of materials that exhibit the desired properties with reliability and durability that can meet a variety of applications.
Ferrites are the dominant form of soft magnetics used in power electronics systems today, primarily due to their low cost. However, they are bulky and reducing their size requires higher frequency operation, which causes high losses. Amorphous alloys and nanocrystalline materials are being explored as potential solutions to this issue, but none of the materials developed exhibit the desired performance characteristics at a competitive cost yet.
New packaging techniques and materials are being developed to improve the performance of power electronics systems at high temperatures with improved reliability over many thermal cycles. These innovations focus on two critical areas of packaging, the die attach and the interconnection. In order to ensure reliability at higher temperature, new die attach techniques and materials are under development, including Silver-Tin alloy soldering, silver sintering, and embedded packaging. Current interconnection methods are also prone to failure and lose reliability at higher temperatures. New interconnection techniques are under development, including ribbon bonding, ball bonding, and embedded packaging.
The Complete Roadmap:
The complete US Power Electronics Technology and Manufacturing Roadmap explores these technology and market trends in detail and summarizes those trends in easy to understand technology and manufacturing roadmaps. Key challenges to and growth opportunities for the US supply chain are identified and a number of detailed recommendations are made to close important gaps and to leverage positions of strength, all aimed towards strengthening the domestic power electronics ecosystem.