Device characteristics of the GaN/InGaN-doped channel HFETs

First dc, small signal, and RF power characteristics of GaN/InGaN doped-channel heterojunction field effect transistors (HFETs) are reported. HFETs with a 1-mum gate length have demonstrated a maximum drain current of 272 mA/mm, a flat G(m) around 65 mS/mm in a V-GS between -0.65 V and +2.0 V, and an on-state breakdown voltage over 50 V. Complete pinchoff was observed for a -3.5 V gate bias. Devices with a 1-mum gate length have exhibited an f(T) of 8 GHz and f(max) of 20 GHz. A saturated output power of 26 dBm was obtained at 1.9 GHz for a 1 mum x 1 mm device.