Comparison of Electrical Characterization of AlGaN/GaN HEMT with Multi-finger Gate

Abstract This paper presents an exhaustive TCAD based comparison of the multi-gate and T-gate AlGaN/GaN HEMT. This paper simulates the DC and RF characteristics of the device and makes an accurate comparison. The important feature of the device such as threshold voltage, drain current output characteristics, transconductance, cut-off frequency, and maximum oscillation frequency were obtained. It is concluded that the shape optimization of the HEMT with multi-finger gates and the advantages over traditional T-gate devices. The device of two-finger gate with 50nm spacing has the best output characteristics, and its maximum saturation current is about 110% the size of the device of four-finger gate with 200nm at VGS=0V. And the gm and the gain of the device with 50nm spacing two-finger gate is 76mS/mm larger than the HEMT of three-finger gate with 200nm. In addition, we also conducted a simulation in the case of changing only refers to finger-gate length and cap-gate length. And it is concluded that the two-finger gate HEMT with 250nm finger-gate length and 2.0µm cap-gate length has the best output characteristics, which output current is 0.159 A/µm at VGS=-1.5V. The results show that AlGaN/GaN HEMT with multi-finger gate have great potential for high power and high frequency applications electronic devices.