PCIM Europe mirrors the ongoing development of new products, from converters, passives, and packaging materials to power devices and wafers

The largest event for power electronics, PCIM Europe, brought together the main players across the supply chain in Nuremberg from 9 to 11 May.

While fewer Chinese and Taiwanese exhibitors were present than recent years, the show featured the leading European and American players, including the major IDMs (Infineon Technologies, onsemi, STMicroelectronics), vertically integrated companies (Bosch, Toshiba, Mitsubishi), compound semiconductor firms (Wolfspeed, Transphorm, Sanan IC), as well as material suppliers (Heraeus, Rogers, KCC).

Ana Villamor, Ph.D., Team Lead Analyst, Power Electronics at Yole Intelligence, part of Yole Group
“On the device side, it is now normal to see Silicon, SiC, and GaN devices in the different booths. Silicon still has a large place in the power semiconductor market, and technology developments are ongoing.”

One example is the decrease in Rdson*A from Toshiba with the upgrade of their Super Junction MOSFET DTMOS VI product. Many companies –such as Alpha&Omega and Toshiba – continued developing packaging discrete parts, particularly to address the demand for thermally-stable and cost-effective 40V MOSFETs. And many products, both low and high power, including old technologies that are still in demand, like Thyristors or IGCTs, were in the booths (CRRC and Hitachi).

A sign that emerging applications for wide bandgap materials are coming ever closer to high-volume reality, integrated systems – such as onboard chargers – were on display in greater numbers than in previous years. In addition, Silicon carbide solutions were out in full force, while there was an increase in gallium nitride exhibitors.

Yole Group experts presented several times at the event, spoke with industry members, listened to conference talks, and observed the latest technology on display. Here they highlight their main takeaways from the event.

Silicon carbide: No sign of slowing down thanks to high-power applications

Despite Tesla’s announcement earlier this year that it would use less SiC in its future power modules, there was no evidence of the SiC device market slowing down at this year’s event, which saw many SiC solutions showcased. This highlights the opportunities being taken by various players across the supply chain as SiC enters high-volume applications.

Poshun Chiu, Technology & Market Senior Analyst, Compound Semiconductors & Emerging Materials at Yole Intelligence
“Automotive is the main driver of high-volume use and will remain so over the next couple of years, particularly with the transition from 400V to 800V battery electric vehicles. Meanwhile, SiC device suppliers are looking to expand their business in other applications such as photovoltaics, EV DC charging infrastructure, and industrial high-power applications.”

The SiC device manufacturing capacity was a talking point among PCIM visitors, where there is a challenge for the supply chain to meet the SiC demand for new and emerging high-volume applications. Wolfspeed recently announced a move towards 8-inch wafer production with a new facility in Germany, a dedicated device fab with high-volume 8-inch wafer manufacturing capacity. Other players are expected to make the transition from 6 to 8 inches, but high-volume supply isn’t expected until 2025 as facilities across the globe are constructed.

The SiC wafer accounts for around 40% of the cost of SiC devices, but with these expansions, companies will be able to adopt a multiple-sourcing strategy as more suppliers enter the market. This will result in the bottleneck moving from the wafer to the device level, another topic of discussion at PCIM.

Gallium nitride: Increased presence as new companies enter the market

In terms of other wide bandgap materials, such as gallium nitride, there was a significant presence of players showing their solutions. While the SiC market targets high-power, high-voltage automotive applications from 650-1200V, today’s main GaN products are based on 650V and lower voltage products (less than 200V). The consumer sector drives the market today, but companies are looking to enter new segments in the future, such as automotive (with onboard chargers) and data centers.

Looking to capitalize on these emerging opportunities, players such as ROHM and Nexperia announced new GaN products on display at PCIM.

Taha Ayari, Ph.D., Technology & Market Analyst, Compound Semiconductor and Emerging Substrates, at Yole Intelligence
Similar to the transition from 6- to 8-inch wafers in the SiC market, the move to larger wafer sizes to prepare for high-volume applications was evident at PCIM: VisIC showed an 8-inch processed wafer; while IVWorks presented an 8-inch GaN-on-Si epiwafer”.

There is also scope for GaN to serve high-voltage applications in the future, and there were hints of this at the show. Transphorm, for example, demonstrated its 1200V GaN-on-Sapphire power devices with its simulation model, aimed mainly at future automotive power systems and charging infrastructure.

Packaging: Laminated busbars reduce inductance at the system level

Low inductance within device packaging and systems is essential to maximize the advantages of using wide bandgap materials, namely operation at high frequency. And maintaining low inductance across the system is crucial, as high-inductance components or interconnections within a system can negate the low-inductance properties of the device packaging. Laminated busbars offer an effective method of low-inductance interconnection, typically used in high-power systems such as wind turbines but also traction inverters in electric vehicles.

PCIM demonstrated that there are still a large variety of power module packaging solutions in the market, particularly in automotive, where there seems to be no apparent movement towards one type of technology. This is partly due to the diverse range of cost, reliability, performance, and usage requirements across the industry, resulting in a diverse range of packaging technologies. However, some common trends have been observed, such as silver sintering for die attach, epoxy molded modules, and enhanced metalized ceramic substrates. The packaging also must provide a good match with the semiconductor technology offering to fully benefit from SiC’s technological advantages.

Typically, the power modules can be integrated on one side, and the DC link capacitors on the other side of a laminated busbar. To decrease inductance further, laser welding connects the capacitor directly to the laminated busbar to negate the need for screws. Or, a step even further, a hybrid product can be created, where the terminals will enter the capacitor structure. French company Mersen, which manufactures both capacitors and busbars, is a company offering such a solution, combining both products.

How to get more value from SiC die via enhanced packaging

Milan Rosina, Ph.D., Principal Analyst, Power Electronics and Batteries at Yole Intelligence
“The trend from soldering to silver sintering to improve power module reliability and thermal dissipation in packaging for automotive power modules was apparent at PCIM. Optimizing the thermal design and materials of the packaging is a more cost-effective way to stretch the performance of the overall device, as it makes up a much smaller part of the overall cost of the module (the packaging within a SiC power module makes up around 20% of the cost, for example, whereas the SiC chip makes up 80%).”

There was also a focus on enhanced ceramic substrate materials, another crucial element in die cooling. Companies are moving from aluminum oxide to silicon nitride and thicker copper layers on the metalized ceramic substrate. This results in better heat spreading and better handling of high currents, which is especially important when considering high-power applications.

Copper sintering also experienced a buzz at PCIM. The technique offers a potentially cheaper solution but brings additional complexity to the process. Many material players and equipment makers are developing or evaluating this new technology. Hitachi has shown power modules with copper sintering for rail applications.

Capacitors: Several devices in one package

Just as optimizing the packaging is essential for getting the full potential out of GaN and SiC technologies, so is optimizing the passive components, such as improve capacitors cooling and form factor.

Products were demonstrated that aim to improve the balancing of capacitors. Currently, it is difficult to balance the capacitors’ currents when placed in parallel, and an imbalance degrades the lifetime of the capacitors and, consequently, the converter.

Hassan Cheaito, Ph.D., Technology & Market analyst, Power & Wireless division, at Yole Intelligence
“Companies TDK, WIMA and Murata displayed module capacitors to solve this, whereby several capacitors are placed in one packaging housing. This improves the capacitor’s thermal management and also the balancing issue because each capacitor has a common electrolytic material. However, there was feedback from some OEMs that feel this approach may limit their design as opposed to using discrete capacitors.”

PCIM Europe mirrored ongoing trends within the power electronics industry and highlighted how innovations in wide bandgap materials are moving closer to high-volume use.

The Yole Group team hopes to see you at the event in 2024!

See all PCIM’s presentations proposed by Yole Group in 2022: