Simulation of GaN HEMT with wide-linear-range transconductance

This paper presents a simulation study to achieve wide-linear-range transconductance of T-gate GaN HEMTs by introducing a δ-doped layer and a p-GaN back barrier. With optimized δ-doping density and location, the transconductance (gm) and current gain cutoff frequencies (fT) are ultra-flat and remain close to their peak values over a wide range of gate-source voltages (Vgs). In addition, a smaller absolute gm3 (third-order derivative of the Ids-Vgs curve) over a wide range of Vgs is obtained in proposed HEMTs. These features are valuable in designing highly linear RF AlGaN/GaN HEMTs.