Power AlGaN/GaN HFETs with excellent Vb/Ron for high speed switching

AlGaN/GaN HFETs with a large current and a high breakdown voltage were fabricated. We examined the switching characteristics and capacitance parameters such as an input capacitance (C-iss), a reverse transfer capacitance (C-rss), a gate to a source charge (Q(gs)) and a gate to a drain charge (Q(gd)), using the GaN HFET devices. An order to confirm the advantage for the high-frequency switching operation of the GaN HFETs compared with Si devices, capacitance parameters and the figure of merit (FOM) Vb/(Ron) for a switching capability were examined. As a result, a law Ciss, Crss, and Qg were obtained and the FOMs of GaN HFETs have one order of magnitude larger than those of Si power devices.