FLOSFIA of Kyoto, Japan reports that it successfully demonstrated α-Ga2O3 normally-off metal organic semiconductor field effect transister (MOSFET). This world-first α-Ga2O3 normally-off MOSFET is comprised of an N+ source/drain layer, a p-type well layer, a gate insulator, and electrodes. The gate threshold voltage, which was extrapolated from I-V curve, was 7.9V. The device is constructed out of a novel p-type corundum semiconductor which functions as an inversion layer.
The company points out that no theoretical study predicted a p-type material which is compatible with n-type Ga2O3 until FLOSFIA researchers discovered p-type Ir2O3 in 2016. For this reason, the company says that the industry has considered it challenging to realize a normally-off Ga2O3 MOSFET.
Back in 2008, Kyoto University initially demonstrated what they claim to be the world’s first single crystal growth of corundum α-Ga2O3 on sapphire Then in 2015, FLOSFIA produced α-Ga2O3 schotty barrier diode (SBD) showing specific on-resistance of 0.1mΩcm2, the world’s lowest specific on-resistance ever. FLOSFIA, then, began offering engineering samples of α-Ga2O3 SBD packaged in TO220.
FLOSFIA plans to manufacture corundum α-Ga2O3 power devices, GaO series, starting from SBD in TO220 packages and then MOSFETs, which will be integrated in AC adopters, electric vehicles, the driver circuits of robots, home appliances, power conditioners for solar cells, and more. According to the company, the GaO MOSFET has a potential to shrink inverter size down to tenths of those using silicon and bring cost down to half of the conventional silicon ones while maximizing conversion.