Back Gate Controlled Pseudo-P-Channel GaN HFET

This paper proposes a novel pseudo-p-channel AlGaN/GaN heterostructure field-effect transistor (PP-HFET). As semiconductor technology advances, GaN devices are preferred for high-power and high-frequency applications due to their high electron mobility, breakdown field, and wide bandgap. Traditional AlGaN/GaN HFETs perform well because of their high electron density and mobility in the 2DEG channel. However, conventional n-type AlGaN/GaN HFETs are limited in applications requiring p-channel devices. The PP-HFET consists of a top reference electrode and a back-gate control electrode. During operation, the top reference electrode of the PP-HET is biased negatively, rendering the device to be initially in the off state. When a negative voltage is applied to the back gate, the two-dimensional electron gas (2DEG) in the channel is regenerated owing to the compensation effect of the electric field. The more negative the back-gate voltage, the higher the ON current of the device, exhibiting the same characteristics as those of a p-channel device. The effects of the device parameters on the output and transfer characteristics are comprehensively examined, and an analytical model is presented. The simulation results illustrate that the threshold voltage of the proposed device based on the back-gate control is approximately -3.5 V, and the current density is as high as 0.1 A/mm, which is much higher than that of the conventional E-mode p-channel GaN HFET based on two-dimensional hole gas.