Silicon Carbide is Paving the Way for Wider Adoption of Electric Vehicles

We are in the midst of the biggest revolution in transportation since Henry Ford rolled out the first production Model T in 1908. Electrification of vehicles is being driven by regulations and countries phasing out the internal combustion engine and looking toward a cleaner, more sustainable future.

The whole automotive industry is transforming, and commitments are being publicly announced by the world's leading automotive manufacturers. GM said it will go all-electric by 2035. Nissan will electrify all models by the early 2030s. Volvo plans to sell only electric vehicles (EVs) by 2030, at which time BMW and Volkswagen expect, respectively, that 50 percent and 70 percent of their European sales will be EVs.

At the heart of this monumental change are power semiconductors, which themselves are undergoing a sea change as the industry begins to orchestrate a shift from silicon to silicon carbide (SiC). The electric motor used to turn the wheels of an EV is typically powered by six silicon insulated-gate bipolar transistors (IGBTs) and diodes using a drive technique called pulse width modulation (PWM). This is where SiC can become advantageous due to its faster switching speeds and recovery characteristics. Replacing IGBTs with SiC saves energy, increases battery life and reduces the size and weight of the heat management system-which further increases EV range.

I elaborated on this earlier in the year during a fascinating panel discussion titled, 'Rethinking Semiconductors,' held during Canaccord Genuity's virtual Global Sustainability Conference. I was joined on the panel by Canaccord analyst Jed Dorsheimer and chip industry veterans Gregg Lowe, CEO of Cree, Bob Daigle, CTO of Rogers Corporation, and my colleague Rob Davenport, director of strategic marketing at Applied Materials.

A recurring and resonant theme was the increasing prominence of power semiconductors and the significant technological and economic advances that will be felt for decades to come. Using revenue forecasts from Yole Développement, the power device market generates about $18 billion in revenue today and is expected to grow to $23 billion in 2025-a four percent CAGR. In comparison, SiC and gallium nitride (GaN) compound semiconductors are projected to grow from approximately $977 million to $4 billion over the same period, a 10X faster growth rate.

Like EVs, SiC chips are at the beginning of a five-year 'S-curve' adoption rate that is signaling a dramatic technology transition, according to Cree's Gregg Lowe. To meet anticipated demand, Cree is building the world's largest SiC fab which is slated to enter production next year.

Bob Daigle's firm, Rogers Corporation, has packaged silicon for decades and foresees SiC-based power ICs shrinking the size of EV battery inverters by roughly 50 percent and increasing system power efficiency to nearly 99 percent. The continued adoption of SiC is also significant because it is fundamentally changing how car manufacturers view semiconductors. Where auto OEMs once obsessed over component-level metrics like cost-per-square-millimeter, they are now looking at SiC technology at the system level in terms of space savings, cooling properties, battery cost and vehicle range. The use of STMicroelectronics' SiC MOSFETs in Tesla Model 3 EVs-and later retrofitted into the Model S and X platforms-has also put the auto industry on notice.

The economics of SiC are improving thanks to breakthroughs in multiple areas. Cree's new fab in Marcy, NY, for example, is expected to manufacture SiC power semiconductors on 200mm wafers, which will significantly lower costs compared to older 150mm wafer lines. And as my colleague, Rob Davenport, observed, conventional Moore's Law transistor scaling may be slowing, but innovations in materials engineering along with breakthroughs in 2D/3D architectures and new packaging techniques will enable advanced compound IC nodes and larger wafer sizes that will bring SiC into high-volume manufacturing (HVM) at higher yields.

A study Applied Materials conducted with a leading automotive power semiconductor supplier compared IGBTs to SiC devices in traction inverters which convert DC current from the EV battery to AC current used to drive the electric motor. We found that SiC offers about a four-percent system efficiency improvement that could increase to greater than six percent as battery and device voltages grow. Currently SiC-based traction inverters are used only in luxury, high-range EV models; however, this will change in the coming years with continued improvements in system efficiency and further SiC cost reduction. By 2030, we expect SiC to be commercially viable compared to IGBTs for use across a wide range of EVs including inner city, low range two seaters.

Once SiC and other compound semiconductors reach HVM, a host of other markets can be opened up, including industrial motor drives, power conversion systems, general industrial applications-even consumer white goods. In retrospect, we will see EVs as just the tip of the SiC iceberg.

'I think compounds can have a big impact on the power electronics world and will enable things that we aren't even thinking about today,' said Davenport. 'This will happen because somebody was willing to adopt something that's a little more risky and then find a way to drive the cost down. Semiconductors have always found ways to do this. It used to be by scaling and today it's through more of a system-level approach.'

As the automotive industry reshapes itself towards electrification, SiC stands to be the perfect technology to enhance electric vehicles through higher efficiency for increased mileage range, further cost reduction and a technology roadmap for continuous performance improvement. Applied Materials is working alongside others in the ecosystem to bring SiC into mainstream, high-volume production, accelerate market adoption and help make our world a more sustainable one.

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