Influence of Transverse Geometry of Sidewall Gates on Characteristics of AlGaN/GaN Fin-HEMTs

This article investigates the influence of transverse geometry of sidewall gates on characteristics of AlGaN/GaN Fin-high-electron-mobility transistors (HEMTs) with rectangular HEMTs (RG-HEMTs), divergent HEMTs (DG-HEMTs), and convergent HEMTs (CG-HEMTs) sidewall gate structure. The subthreshold characteristics of the three types of devices have been compared. The pinch-off voltage of the DG-HEMTs and CG-HEMTs exhibits a slightly positive shift compared to RG-HEMTs, indicating that the pinch-off voltage depended on the smallest nanochannel width in Fin-HEMTs. What’s more, the DG-HEMT exhibits a pronounced depletion effect on channel electrons, and an enhanced gate control capability, improving the threshold voltage stability and suppressing the short-channel effects. At the source side in the channel under the gate, a high electron barrier was been observed in the DG-HEMTs, effectively blocking the injection of carriers from the source into the channel as the drain voltage increased. Additionally, at the corner from the assess region to the channel, the DG-HEMTs displayed the fastest potential rise. The effective electron transport has been enhanced in the channel, making it possible to reach an enhanced electron velocity along most of the channel length, leading to a reduced knee voltage. This conclusion has been validated through simulations of Fin-HEMTs with different channel widths. Furthermore, the DG-HEMT delivers improved DE and PAE at V $_{\text{DC}}$ $=$ 9 V.