DENSO and Kyoto spin-off FLOSFIA to develop gallium oxide-based power semiconductor device for EVs

Automotive supplier DENSO Corp of Kariya, Aichi prefecture, Japan, and Kyoto-based FLOSFIA Inc are partnering to develop a next-generation power semiconductor device that is expected to reduce the energy loss, cost, size and weight of inverters used in electric vehicles (EVs). Through the joint development project, the two firms aim to improve the efficiency of EV power control units (key to driving the widespread use of EVs).

Since 2007, DENSO has provided power control units (PCUs) for hybrid and electric vehicles, using an inverter to control the power supplied from the battery to the motor generator. To use electric energy more efficiently, energy losses during the DC to AC conversion by the inverter must be reduced, so DENSO is conducting R&D on low-loss power semiconductors.

FLOSFIA was spun off from Kyoto University in 2011 and specializes in R&D and commercialization of gallium oxide (α-Ga2O3) thin films formed by mist chemical vapor deposition (CVD). DENSO has also acquired new shares issued by FLOSFIA in its Series C funding round.

Kyoto University’s professor Shizuo Fujita pioneered the application of corundum-structured α-Ga2O3 for use in semiconductors. With a wide bandgap of 5.3eV and high electric breakdown field strength, α-Ga2O3 can better withstand high-voltage applications, making it possible to replace existing silicon and silicon carbide (SiC) power semiconductors.

Making use of physical properties of α-Ga2O3, FLOSFIA has developed low-loss power devices including a Schottky barrier diode (SBD) with what is claimed to be the lowest specific on-resistance on the market. The firm aims to develop its own production lines, targeting commercial production in 2018.