Effect of Gate Field Plate and Γ(gamma)-Gate Structures on RF Power Performance of AlGaN/GaN HEMTs

In this work, effect of field plate and Gamma(gamma)-gate structures on RF power performance of AlGaN/GaN high electron mobility transistors (HEMTs) are reported. 3 mu m drain source space, 0.6 mu m gate length AlGaN/GaN HEMTs with field plate length of 0.5 mu m and Gamma-gate head length of 1.2 mu m (with the 0.5 mu m field plate length) have been fabricated. At 8 GHz with a drain bias of 25 V, for field plate and Gamma-gate 0.6 mu m x 8 x 125 mu m HEMTs, small gain of 10,5 dB and 10,9 dB, at 3dB gain compression a continuous wave output power of 35.5 dBm and 36.7 dBm, power-added efficiency (PAE) of 43.4% and 43.2% are measured respectively. For Gamma-gate 0.6 mu m x 8x250 mu m AlGaN/GaN HEMTs, with drain bias of 50V, an output power of 40.83 dBm (6,05 W/mm) and PAE of 30% at 8 GHz and an output power of 41.22 dBm (6,64 W/mm) and PAE of 50,3% at 2 GHz have also been obtained without using via hole technology.