Present status and challenges of AlGaN/GaN HFETs

This paper reviews the potential and present status of AlGaN/GaN HFETs. The high potential of these devices for high-power and high-frequency operation are explained from the view point of the unique physical properties of GaN and AlGaN/GaN hetero-structures. The present status of these device performances are briefly introduced. Over 200 W operation at 2 GHz and 5.3 W operation at 30 GHz have already been achieved so far, verifying the high-potential of this material system. Material issues for further improvements of these device performances are discussed.