AlGaN/GaN HEMTs on (001) Silicon Substrate With Power Density Performance of 2.9 W/mm at 10 GHz

AlGaN/GaN High Electron Mobility Transistors (HEMT) on a (001)-oriented silicon (Si) substrate are fabricated. The device with a gate length of 300 nm and a total gate periphery of 300 μm exhibits a maximum dc drain current density of 600 mA/mm at V_GS = 0 V with an extrinsic transconductance (g_m) of about 200 mS/mm. An extrinsic current gain cutoff frequency (f_t) of 37 GHz and a maximum oscillation frequency (f_max) of 55 GHz are deduced from S-parameter measurements. At 10 GHz, an output power density of 2.9 W/mm associated to a power-added efficiency (PAE) of 20% and a linear gain of 7 dB are obtained at V_DS = 30 V and V_GS = -2 V. To our knowledge, these power results represent the highest output power density ever reported at this frequency on GaN HEMT grown on (001) Si substrate.