Paul van Gerven
24 February

Leveraging gallium nitride research from Imec and decades of experience in power semiconductor R&D and manufacturing, Onsemi carve-out Belgan in Oudenaarde is looking to become the beating heart of Europe’s “GaN valley.”

The semiconductor manufacturing site in Oudenaarde is starting a new chapter. Divested by previous owner Onsemi, an investment consortium united in Belgan Group is steering the 6-inch fab onto the path of the next big thing in power electronics: gallium nitride (GaN). “Our goal is to become Europe’s first GaN foundry qualified for automotive ICs,” says general manager Rob Willems of Belgan.

Currently a market no bigger than 100 million dollars, GaN has only taken a few nibbles out of the 50-billion-dollar global power electronics market that’s still dominated by silicon. The compound semiconductor, however, has some powerful aces up its sleeve. Compared to silicon, GaN enables higher energy efficiency, higher switching frequency and higher power density as well as smaller component footprints.

These advantages come at a cost, though. Literally. “A GaN chip will be more expensive than the equivalent silicon device,” Belgan CTO Marnix Tack admits. “However, on the system level, GaN enables savings by reducing the number of peripheral components or eliminating the need for cooling systems. Moreover, customers are willing to pay a premium for GaN’s characteristics. It’s been estimated, for example, that the adoption of GaN power electrics will increase the range of electric vehicles by 20-30 percent. That’s a feature no carmaker can ignore,” says Tack.

If GaN technology has so much to offer, why hasn’t it taken off sooner? “The first commercial GaN devices were launched ten years ago, but it has taken time for the technology to mature and costs to drop. This included making larger wafer sizes available. Originally, GaN was limited to 2 or 3-inch wafers. Thanks to GaN-on-Si epitaxy, diameters have increased to 8 inches.”


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“Another reason for the relatively slow adoption is the disruptive nature of GaN. You can’t simply replace a silicon component with a GaN one: you need to redesign the whole system around it. OEMs only take such a big step once they’re convinced the technology and its supply chain is ready.” Slowly but surely, companies that serve consumer, automotive, renewable energy and data center markets have started to embrace the GaN technology. “I believe that we passed the inflection point last year.”


Belgan aims to capitalize on this gaining momentum. Most recently, the fab has been running 0.35-0.7-micron processes on 6-inch wafers to manufacture low, medium and high-voltage analog CMOS and BCD technologies, primarily for the automotive market. “Gradually, we’ll transition to GaN technology and add 8-inch wafer fabrication. Initially, we’ll focus on consumer and industrial markets. Meanwhile, we’ll be working on the qualification for GaN automotive production. That’s where we expect the biggest volumes in the future,” explains Willems.

The foundry’s GaN expertise has been developed in-house over the past ten years, working closely together with nearby Imec. Willems: “Building on this collaboration, our CEO Alan Zhou envisions bringing together universities and other research organizations, product developers, suppliers and customers in the GaN Valley ecosystem.” US-born and MIT-educated Zhou previously served several semiconductor companies in the US and China. He has been placed at the helm by Belgan’s owners, the investment firms Rockley Group, based in Oxford and Shanghai, and the Wuxi Group, incorporated in Hong Kong.

Belgan Oudenaarde inside
Credit: Belgan

The foundry business is a different ball game than being a production site for an IDM. Why do you think you can make the switch?

Tack: “We used to be part of a large global corporation, serving ‘internal’ customers with their own requirements. Developing and manufacturing products for external businesses won’t be all that different, except for sales and business development aspects, obviously. Those business units weren’t part of the Belgan carve-out, so we have to set them up ourselves. Our well-connected shareholders are supporting us to do that.”

Willems: “We’re used to running a large number of different processes. In our current high-voltage technology, for example, we have 180 variations. In other words, we’re familiar with operating our fab in a foundry-like manner.”

What do you bring to the table to be successful as a foundry?

Tack: “We’ve co-developed our technologies with Imec and other partners. This will serve a growing community of fabless GaN companies well. We have decades of experience in automotive. And, increasingly, chip users prefer their key suppliers to be nearby. GaN chips aren’t commodities, they’re specialty technologies that require close collaboration. This is particularly the case for the car industry. Direct involvement of OEMs with semiconductors had already been increasing over the past few years, driven by the need to innovate. The recent shortages have reinforced that interest.”

Willems: “We know the market, we know the technology. Those are valuable assets for a business that’s not primarily driven by cost. GaN isn’t like silicon in that respect, not yet at least. By moving to 8 inch, we’ll be competitive in this market. We’re strategically located in Europe to support design companies targeting the EU market. Currently, there’s no GaN-focused foundry in Europe.”

Anything related to semiconductors and China is sensitive these days. What are the connections of your investors to China?

Willems: “We’re most definitely not Chinese-owned – neither of our investors originates in China. I think it would have been nearly impossible to sell off a semiconductor business to the Chinese anyway. Especially for an American company like Onsemi.”

Main picture credit: Belgan