Enhancement of Johnson figure of merit in III-V HEMT combined with discrete field plate and AlGaN blocking layer

The performance of AlGaN/GaN HEMT is enhanced by using discrete field plate (DFP) and AlGaN blocking layer. The AlGaN blocking layer provides an excellent confinement of electrons toward the GaN channel, resulting very low subthreshold drain current of 10(-8) A/mm. It reveals very high off state breakdown voltage (BV) of 342 V for 250 nm gate technology HEMT. The breakdown voltage achieved for the proposed HEMT is 23% higher when compared to the breakdown voltage of conventional field plate HEMT device. In addition, the DFP reduces the gate capacitance (C-G) from 12.04 x 10(-13) to 10.48 x 10(-13) F/mm. Furthermore, the drain current and transconductance (g(m)) reported for the proposed HEMT device are 0.82 A/mm and 314 mS/mm, respectively. Besides, the cut-off frequency (f(T)) exhibited for the proposed HEMT is 28 GHz. Moreover, the proposed HEMT records the highest Johnson figure of merit (JFOM) of 9.57 THz-V for 250 nm gate technology without incorporating T-gate.