High Performance Enhancement Mode Dual Electron Layer High Electron Mobility Transistor: Design and Analysis

This work presents a design and simulation of a new enhancement mode (E-Mode) electrically doped high electron mobility transistor (HEMT). The normally OFF or E-mode is realized by employing an optimized p -type GaN-pocket near GaN/AlGaN interface, in alignment with the gate in the proposed structure. The GaN pocket creates a conduction barrier in the two dimensional (2D) Electron-Gas (2DEG) layer already present at AlGaN/GaN interface. This way an E-mode behavior is realized in the proposed structure. Further, extra electron layers/conduction paths get created under the source and drain terminals by employing metals of specific work functions, a charge plasma approach. So the proposed device is a considered as a hybrid device with dual conduction paths, one 2DEG and the other one charge plasma (CP) electron-gas (CPEG). The realization of dual conduction paths results in substantial improvement in the performance of the proposed E-Mode GaN-HEMT device. Out of a 2D experimentally calibrated simulations performed here, it can be seen that the proposed hybrid E-Mode GaN HEMT device results in 7× increase in ON-current (I ON ), ~272% increase in transconductance (g m ), ~74% enhancement in cutoff frequency (f T ), ~87% and ~122% improvement in maximum-oscillation-frequency (f max ) and maximum bandwidth respectively in comparison the conventional GaN-HEMT device.