Recent advances and future prospects on GaN-based power devices

Recent advances of GaN Gate Injection Transistors (GITs) and their applications to power switching systems are reviewed. The GITs are fabricated on cost effective Si substrates in a large diameter up tp 6inch, which exhibit normally-off operations by the use of p-AlGaN over an AlGaN/GaN hetero-junction. The GIT is free from the current collapse up to 600V enabling reliable operation of the power switching systems. The inverter for motor drive using GITs enables high efficiency of 99.3% at 1.5kW which is higher than that by conventional Si-IGBT (Insulated Gate Bipolar Transistor). The GITs are also applied various circuits in a power supply taking advantages of the high frequency operations. A GaN-based LLC resonant converter used in isolated DC-DC converter enables 1MHz operation with high efficiency of 96.4%, while conventional Si devices cannot be operated at such high frequencies. The above results demonstrate very promising potentials of high-voltage normally-off GaN GITs.