Improved DC and RF performance of high power AlGaN/GaN HEMTs with a novel inner field-plate

An AlGaN/GaN high electron mobility transistor (HEMT) device based on a novel inner field- plate (IFP) structure is proposed and fabricated. At an optimum bias condition of the inner field-plate (V_IFP), the gate leakage current of the device has been reduced by more than 15%. In addition, the microwave performance has been found to be improved considerably with increased cut-off frequencies of f_T = 6.9 GHz and f_MAX = 14.4 GHz at a gate length of 1 mum. The IFP-HEMT biased at the inner field-plate voltage of V_IFP=8 V and V_DS=15 V demonstrated an increased maximum output power of 16.4 dBm at 2 GHz compared to the maximum output power of 15.5 dBm for the reference case in which the inner plate is connected to the gate electrode (V_IFP=V_GS).