We will use SiC in hybrid vehicles, says Toyota
Toyota rates SiC as an important tool in its bid to provide sustainable motoring, and will use it in power electronics for hybrid vehicles by 2020.
So says Kimimori Hamada, manager of the research department of the Japanese car maker s semiconductor engineering division, who is responsible for developing SiC technologies.
Speaking at the International Conference on Silicon Carbide and Related Materials in Otsu, Japan, on October 14, Hamada said Toyota could use the material commercially as early as 2010.
The 10-year margin of error gives Hamada and the SiC industry in general time to meet Toyota s strict financial criteria.
“Silicon carbide has little chance of being used unless it can be had at a cost that is the same as, or lower, than that of silicon,” Hamada told the conference.
This will partly be achieved by delivering improved performance with SiC beyond the levels that silicon devices can attain.
However, Toyota s financial model for future hybrid technologies also demands that chips for inverter components be made on SiC wafers of at least 5 inches in diameter. The search for the so-called "Ultimate Eco-Vehicle" will also require higher-power-density, normally-off devices with energy loss performance an order of magnitude lower than silicon.
To this end, Toyota has developed ultra-high-quality SiC using a method that it calls "repeated a-face growth", in collaboration with Japanese compatriots Denso. This technique, reported in Nature in August 2004, provides the company with 3-inch wafers with a defect density of only 250 cm-2.
Hamada told the conference that GaN will also have a role in Toyota s future devices and claimed that his group has made the world s first enhancement-mode AlGaN/GaN HEMTs.
These devices were not described in detail, as they were first reported at the 2007 Power Conversion Conference and Hamada conceded there was some question about whether they were truly enhancement mode.
Citing evidence about carbon dioxide emissions, from the recently announced Nobel peace prize recipients, Toyota s environmentalism is at once both passionate and pragmatic.
In Hamada s words, “In our case, sustainability refers to the ability of the end users to continuously enjoy the convenience provided by automobiles.”
“High expectations are being placed on wide-bandgap semiconductors in producing key devices for achieving these goals,” he said.
“We hope that the professionals gathered here from around the world will share in our commitment by pursuing research and development to bring a wonderful future to mankind.”Author
Andy Extance is a reporter for compoundsemiconductor.net.