Current Status and Future Prospects of GaN HEMTs for High Power and High Frequency Applications

In this paper, recent progress of GaN high electron mobility transistors (HEMTs) will be addressed. GaN HEMTs have been developed mainly for power amplifiers and power conversion units. For mass production, suppression of trapping phenomena, such as current collapse was required. Surface structures and GaN buffer layers are key features for controlling trap formation, resulting in long reliability. Drift phenomena which are critical characteristics for power amplifier were also investigated in detail. For power conversion, normally-off technology is essential. In this study, we developed the insulated-gate structure using atomic layer deposition.