Electron Tri-Layer Enhancement Mode High-Electron-Mobility Transistor: Design and Analysis

In this work, we report the design of a novel enhancement mode (E-mode) trielectron-layer (TEL) AlGaN/GaN high-electron-mobility transistor (HEMT) for the first time. The realization of the E-mode (initially off) operation has been done by employing an optimized P-GaN pocket buried in the GaN channel layer. In the proposed structure, double two-dimensional electron gas (2DEG) layers get created: one at the heterojunction of the top AlGaN layer and the bottom AlGaN layer, while the other at the heterojunction of the bottom AlGaN and GaN channel layer. Besides, charge plasma electron gas (CPEG) layers are induced by the source and drain electrode in the source and drain regions. Therefore, the uniqueness of this structure is the presence of three conduction paths: two 2DEG layers and one CPEG. The presence of the double-layer 2DEG and single CPEG layer enhances the overall performance of the device, like transconductance (G _m), cutoff frequency (f _T), etc. A two-dimensional (2D) calibrated simulation study shows that the device exhibits a threshold voltage (V _th) of 3.5 V. Further, a significant improvement of 284% and 97.4% is achieved in transconductance and breakdown voltage of the proposed device, respectively, in comparison to the conventional HEMT. A comprehensive study of the effect of trap density and AlN properties on the performance of the proposed structure has also been performed.