Denso Corp will start a development project for applying gallium oxide (Ga2O3)-based power devices to auto parts in cooperation with Flosfia Inc.

Flosfia (Kyoto Prefecture) is a venture firm spun off from Kyoto University. They aim to apply Ga2O3-based power devices to power control units (PCUs) equipped with, for example, an inverter that controls the driving motors of electric vehicles (EVs).

In the field of power devices, Ga2O3 is drawing attention as the "third next-generation material" that is on par with silicon carbide (SiC) and gallium nitride (GaN). Ga2O3 has a wider band gap than SiC and GaN, which have a lower loss than silicon (Si), a commonly-used power device material. So, Ga2O3 can potentially realize a power device that has a further lower loss and a high withstand voltage at a low cost.

Ga2O3 can have several crystal structures, and Flosfia deals with "Α Type," which has a crystal structure called "corundum." The Α Type has a wider band gap than "Β Type," which is a common Ga2O3.

Flosfia forms an Α Type Ga2O3 film by using "mist CVD method." With the method, mist of solution containing raw materials is generated by supersonic vibration, and it is sprayed on a substrate to form a thin film.

At this point, the film can be formed at an atmospheric pressure, eliminating the need to create a vacuum state. As a result, it becomes easier to lower the cost of production equipment and, thus, production cost. The mist CVD method of Flosfia is based on the research of a research group led by Shizuo Fujita, professor at the Graduate School of Engineering, Kyoto University.