Toyota Motor Corp changed its "main" next-generation power semiconductor.

The power semiconductor devices (power devices) used for the inverters and boosting converters of Toyota's electric vehicles such as "Prius" and "Aqua" were expected to be switched from the current Si (silicon)-based IGBTs to low-loss SiC power devices in stages in about 2020.

It is because Toyota started to equip vehicles prototyped based on the Prius and "Camry" hybrid vehicles (HEVs) with SiC power devices and repeat running tests and experiments on public roads in about 2014, showing positive attitudes toward SiC.

However, Nikkei xTech/Nikkei Electronics found that Toyota decided not to employ SiC and will use a new IGBT instead. The new IGBT is expected to be employed for vehicles that will be released in 2019 under the Toyota brand at the earliest.

An SiC power device-equipped vehicle prototyped based on the Camry HEV. It was used for a test on public roads. (source: Toyota)

Shortage of SiC wafers

The reason why Toyota decided not to employ SiC power devices in 2020 is partly because there is a shortage of SiC wafers, which are needed to manufacturer those devices, said multiple engineers and researchers who are well-versed in power devices.

In other words, with the current supply quantity (or the supply quantity one or two years later) of SiC wafers, even though high-grade vehicles such as "Lexus" might use SiC wafers, it is not possible to supply SiC wafers to a large number of mass-produced vehicles, they said.

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