Switching Properties of 600 V Ga2O3 Diodes With Different Chip Sizes and Thicknesses

Gallium oxide (Ga₂O₃) devices are currently under investigation regarding their application in power electronics, but so far little research has been done on their switching properties. This article analyzes different types of new 600 V $\beta$-Ga₂O₃ Schottky diodes, including their first evaluation as freewheeling diodes in a 400 to 200 V buck converter with an output power up to 2 kW and switching frequencies up to 350 kHz, as well as double pulse tests at dc-link voltages up to 500 V, currents up to 40 A and peak voltage slew rates exceeding 100 V/ns. 600 µm thick TO247 packaged diodes with three different chip sizes are compared with commercial Si and SiC diodes of similar chip size. Furthermore, novel 200 µm thin Ga₂O₃ diodes with two different chip sizes are assembled on custom packages and compared with a commercial SiC diode of similar anode size assembled in the same way. The Ga₂O₃ diodes exhibit switching properties similar to those of the SiC counterparts. Under heavy load conditions, the buck converter efficiencies with Ga₂O₃ diodes exceed the efficiencies with a Si fast-recovery diode, while naturally still being lower than those with SiC diodes. Improving the tradeoff between on-resistance and capacitive charge appears to be vital for future applications.