GaN power switching devices

State-of-the-art device technologies of GaN power switching transistors are reviewed. The presented technologies solve the technical issues on GaN transistors for practical use replacing currently used Si-based power devices. Thick epitaxial growth over 6-inch Si substrates enables low cost fabrication of GaN devices with high breakdown voltages. A new operating principle for the normally-off GaN transistor called Gate Injection Transistor (GIT) is proposed in which hole injection from the p-type AlGaN gate increases the drain current by conductivity modulation. Six GITs are integrated onto a single chip on silicon as the world first GaN-based monolithic inverter IC. The inverter IC successfully drives a motor with low operating loss which is 42% reduced from that of the conventional IGBT (Insulated Gate Bipolar Transistor)-based one. These technologies are indispensable for wide-spread use of GaN power switching transistors in the future.