Stable CW operation of field-plated GaN-AlGaN MOSHFETs at 19 W/mm

We report for the first time the dc and radio frequency (RF) operation of a field-plated GaN-AlGaN metal-oxide-semiconductor heterostructure field effect transistor (MOSHFET). At 2 GHz and an RF output power level of 19 W/mm (drain bias 55 V), the device exhibited a remarkably stable operation for times in excess of 100 h. In contrast, a similar geometry HFET from the same wafer continuously degraded from 17 W/mm down to 14 W/mm within the first 20 h. We attribute the stable performance of the MOSHFET at high microwave powers to the extremely low gate-leakage currents and the current collapse-free operation resulting from the field-plated design.