In 2008, the commercialization of the silicon carbide (SiC) MOSFET marked a major turning point for the power semiconductor market, representing its first significant development in decades. This technology was pioneered in electric vehicles (EVs) with the 2017 Tesla Model 3.

The SiC MOSFET is a transistor that promises high power density, greater efficiency, and is less fallible to high temperatures. The result yields benefits for electric vehicles (EVs), including longer ranges, faster charging, and potentially even lower battery electric vehicles (BEVs) costs.

In the power electronics of EVs, SiC MOSFETs have seen an incredible surge in adoption in the past five years in cars from OEMs such as Tesla and Hyundai. In fact, IDTechEx research found that SiC inverters made up 28% of the BEV market in 2023.

GaN HEMTs, a more nascent technology, could be the next major disruptor in the EV market. They present key efficiency benefits but face significant challenges to adoption, such as their ultimate power-handling capability. There is considerable overlap between SiC MOSFETs and GaN HEMTs, and both will have a place in the automotive power semiconductor market.

Given the tradeoffs, where will we see SiC and GaN take hold in the power electronics market?

The new IDTechEx report, “Power Electronics for Electric Vehicles 2025-2035: Technologies, Markets, and Forecasts“, analyzes the adoption of Si IGBTs, SiC MOSFETs, and GaN HEMTs, as well as developments in the automotive power electronics market, and technologies to uncover the market landscape, of which IDTechEx expects to grow to US$36 billion by 2035.

SiC MOSFETs are already becoming the go-to technology

Obstacles in performance, reliability, and production capacity have been tackled with the rapid scale-up of facilities, driving down the cost of SiC MOSFETs dramatically. Although SiC MOSFETs are still, on average, 3x more expensive than an equivalent Si IGBT, its properties make it a solution embraced by Tesla, Hyundai, and BYD (among a multitude of growing Chinese OEMs). Others have indicated future adoption through announcements, including Stellantis, Mercedes, and the Renault-Nissan-Mitsubishi alliance, among others.

SiC MOSFETs present a smaller form factor and can also decrease the size of accompanying passive components, such as the inductor in a traction inverter. Lighter and more efficient, the range of a BEV can be increased by approximately 7% by switching from Si IGBTs to SiC MOSFETs in the inverter, tackling consumer concerns about range. On the other hand, by using SiC MOSFETs, one could get the same range with a reduced battery capacity, contributing to a lighter, lower cost, and more sustainable vehicle.

As battery capacity increases, so does the overall energy savings achieved through the use of SiC MOSFETs. Originally, SiC MOSFETs and larger batteries were reserved for mid to high-value EVs with larger batteries. With new mainstream and budget vehicles such as the MG MG4, BYD Dolphin, and Volvo EX30 having battery capacities greater than 50kWh, SiC MOSFETs are ready to penetrate Europe and China’s mainstream passenger vehicle sectors. This accompanies the head start gained from the US, with Tesla being the first major OEM to use SiC MOSFETs in its Model 3.

IDTechEx’s report, “Power Electronics for Electric Vehicles 2025-2035: Technologies, Markets, and Forecasts”, predicts that the demand for SiC MOSFETs will increase 10-fold between 2023 and 2035, driven by greater efficiency and adoption of higher voltage platforms, with applications in inverters, onboard chargers, DC-DC converters.

GaN’s Market Status

Both SiC and GaN are wide bandgap (WBG) semiconductors. Since GaN has an even wider bandgap than SiC, in theory, the advantages in efficiency in SiC could potentially be exceeded by GaN. The absolute upper limit to the switching frequency of Si IGBTs is 100kHz. For SiC this increases an order of magnitude to approximately 1MHz, and GaN can go a factor of ten even higher, to 10MHz.

However, this is only looking at one side of the story, and there are barriers to entry for GaN in power electronics. Firstly, with ultra-high switching frequencies, engineers need to tackle multiple technical problems, such as EMI (electromagnetic interference), gate control, parasitic effects, thermal effects, and increased switching losses. Secondly, at the device level, SiC MOSFETs and GaN HEMTs are, in fact, very different. GaN devices are typically grown on silicon substrates, while for SiC, a native SiC substrate is used. While Si substrates have a much lower cost than alternatives such as SiC and sapphire, it throttles the potential of a GaN device, constraining it to lateral configurations and low voltages, preventing it from being useful in the traction inverter of an EV, which typically operates at 600-1200V and hundreds of kW.

There are alternatives and developing technologies to tackle these issues that could drive GaN’s progress in high-voltage power electronics., such as vertical GaN devices and multi-level topologies. IDTechEx analyzes these technologies and companies in its “Power Electronics for Electric Vehicles 2025-2035: Technologies, Markets, and Forecasts” report. It should be noted that GaN does hold a significant market share in the low voltage auxiliary electronics in vehicles, which are present in not only EVs but mild hybrids and internal combustion engine vehicles.

The Future of GaN and SiC

IDTechEx predicts the market share for SiC MOSFETs to be well over 50% by 2035, accompanying significant growth in the automotive power semiconductor market. SiC MOSFETs offer a solution to many narratives swirling around the EV market: range anxiety, fast charging, sustainability, and the rise of 800V architectures.

However, IDTechEx acknowledges that GaN will enter the EV power electronics market over the next five years. This market entry will vary by component: earlier for the onboard charger, DC-DC converter, and later for the traction inverter. Although GaN isn’t there yet, developments in substrate technology, vertical devices, and multi-level topologies will be accompanied by investments from large players in the automotive power semiconductor space, such as ROHM, Infineon, and Renesas. This will soon make GaN a realistic and widespread solution for EV power electronics.

Over the next decade, one can expect the coexistence of Si, SiC, and GaN in the EV power electronics ecosystem.

By: DocMemory
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