SiC and GaN: a Tale of Two Semiconductors

BY Ahmed Ben Slimane, Ezgi Dogmus and Poshun Chiu

In the last couple of decades, the worldwide SiC and GaN scene has been characterised by development, growing industry acceptance.

In the last couple of decades, the worldwide SiC and GaN scene has been characterised by development, growing industry acceptance and the promise of billion-dollar revenues. The first commercial SiC device hit the scene in 2001 in the form of a Schottky diode from Germany’s Infineon. Rapid development has followed, and this industry sector is now poised to reach over $4 billion dollar market by 2026.

Meanwhile, GaN first wowed industry pundits in 2010 when US-based EPC delivered its super-fast switching transistors. Market adoption hasn’t yet matched that of SiC but come 2026, power GaN revenues could hit $1 billion.

The secret of future market success for each technology lies in electric and hybrid electric vehicles (EVs/HEVs). Indeed, for SiC, the EV/HEV market is truly the sweet-spot right now – at least 60% of the total market, which is in excess of $ 2.5B revenue, is expected to come from this sector.

Tesla kick-started the SiC power device market in 2017 when it became the first automaker to add SiC MOSFETs, sourced from STMicroelectronics, in an in-house main inverter design in its Model 3. Other automotive players have been quick to follow in EV giant’s footsteps, including Hyundai, BYD, Nio, General Motors and many others.

For example, China’s, Geely Automobile recently announced it is collaborating with ROHM, Japan on SiC-based traction inverters for its EVs, while NIO – China’s answer to Tesla – is to implement a SiC-based electric drive system in its vehicles. At the same time, OEM automaker and semiconductor manufacturer, BYD, has been developing SiC modules for its entire line of EVs.

Also, just last year, China-based electric bus manufacturer, Yutong, revealed it is to use SiC power modules manufactured by StarPower, China, in the power trains of its buses. These modules use SiC devices from Wolfspeed, US.

Over in Korea, Hyundai has turned to Infineon’s SiC-based power module for the 800 V battery platform of its electric vehicles while in Japan, Toyota is using SiC booster power modules from Denso in its Mirai fuel cell electric vehicles. And in the US, General Motors has just signed up Wolfspeed to supply SiC for its EV power electronics.

Europe tells a different story, where car manufacturers have been slower to embrace SiC, but change is afoot. In June this year, Renault and STMicroelectronics joined forces to develop SiC and GaN devices for EVs and HEVs, and more announcements are expected soon from Daimler, Audi and Volkswagen.

Importantly for the likes of Wolfspeed, Infineon, STMicroelectronics, ROHM and Onsemi, automotive OEMs also prefer to buy wafers and devices from multiple sources to ensure reliable supply. Factor in the vast sums of money that China, and increasingly other nations, are pouring into the SiC supply chain, and volume sales will only continue to rise.

And along the way, the thorny issue of cost is also being addressed. Without a doubt, at the component level, silicon IGBTs are vastly cheaper than the SiC equivalent, and are not going to disappear from power applications anytime soon. But Tier-1 manufacturers and OEMs have indicated that implementing high power density SiC into, say, an inverter design, cuts costs at a system level thanks to the space- and weight-savings that could stem from the need for fewer components.

But where does this leave GaN? This wide-bandgap semiconductor has yet to witness the success of SiC in the EV/HEV sector, but thanks to its high frequency operation and efficiencies, OEMs are either eyeing the technology with intense interest or have development programs underway.

Early days

GaN power devices can already be found in low volume, high end photovoltaic inverters and are being increasingly used in fast chargers for a range of mobile devices including smartphones. Indeed, Ireland’s Navitas, Power Integrations of the US, as well as Innoscience of China are all manufacturing GaN power ICs for the burgeoning fast charger market.

Given this activity, GaN power device revenues are estimated to reach around $100 million in 2021. But as GaN device suppliers look to enter other markets to raise volumes, this figure is expected to swell to that $1 billion by 2026. And the EV/HEV market is the first to watch.

It’s early days for GaN in electric vehicles. Many power GaN players have developed and auto-qualified 650 V GaN devices for onboard chargers and DC/DC conversion in EVs/HEVs, with myriad partnerships already formed with automotive businesses.

For example, Canada-based GaN Systems supplies its devices to US EV start-up, Canoo, for onboard chargers, and has also partnered with Canada-based EV motor drive supplier, FTEX, to integrate 650V GaN power devices into systems for e-scooters. At the same time, Transphorm, US, has teamed up with automotive supplier, Marelli, to provide devices for onboard charging and DC/DC conversion.

STMicroelectronics is expected to supply its yet-to-be auto-qualified devices to Renault for on EV applications, while EPC, now delivering automotive-qualified low voltage GaN, is working with French-based Brightloop to develop affordable power supply converters for off-high way and commercial vehicle. And last year, Texas Instruments also qualified its 650V GaN devices for automotive applications.

But as the onboard charger and DC/DC market segments gather momentum, the billion dollar question, quite literally, for GaN is will the technology make it to the main inverter of the EV/HEV powertrain, and reap spectacularly high volumes, and high revenues that SiC is beginning to see? Early industry developments indicate this is possible.

In February last year, Nexperia of The Netherlands hooked up with the UK consultants, Ricardo, to develop a GaN-based EV inverter design. The announcement was swiftly followed by VisIC Technologies of Israel partnering with German auto-supplier, ZF, to develop GaN semiconductors for 400 V driveline applications.

Then, in September this year, GaN Systems signed a $100 million deal with BMW to provide the capacity to manufacture GaN power devices for the German auto-maker’s electric vehicles, solid evidence that OEMs are serious about GaN. And in a truly significant step, Navitas is to become a publicly traded company with a market value of $1.04 billion, by combining with special-purpose acquisition company Live Oak Acquisition. The GaN power IC player recently announced it is to supply devices to Swiss-based Brusa HyPower for onboard chargers and DC/DC converters, and as a public company intends to put its weight behind product development for EVs/HEVs and other markets.

Beyond the deals, partnerships and mergers, early work on GaN modules also indicates that this compound semiconductor is following in the footsteps of SiC, with industry players gearing up for more widespread industry integration. For example, GaN Systems is offering a power evaluation module kit to design engineers while Transphorm has been working with Fujitsu General Electronics on a GaN module that targets industrial and automotive applications.

So, what next for both SiC and GaN? As manufacturers of power SiC devices ready for the multi-billion-dollar market that EVs/HEVs will bring, will GaN experience the same success story? Widespread OEM adoption of GaN in drivetrain inverters would radically impact market forecasts, but right now, we can only wait and see.