MICROWAVE OPERATION OF GAN ALGAN-DOPED CHANNEL HETEROSTRUCTURE FIELD-EFFECT TRANSISTORS/

We report on the microwave operation of 1 mu m gate AlGaN/GaN-doped ch annel heterostructure field effect transistors (DC-HFET's) with the cu toff frequency f(T) of 18.3 GHz. These devices exhibit the cutoff freq uency-gate length product in excess of 18 GHz . mu m, comparable to th at of the state-of-the-art GaAs MESFET's. We explain these improvement s in the device performance by the increased sheet carrier density in the device channel and by a reduction in the parasitic series resistan ces, caused by doping the device channel.