Study on the Negative Transconductance in a GaN/AlGaN-Based HEMT

Abstract

The presented work mainly intends on reinvestigating the origin of the negative transconductance at higher gate voltages, in a GaN/AlGaN-based high-electron-mobility transistor (HEMT). The analysis is done using TCAD simulations, where the simulated GaN/AlGaN-based HEMT is calibrated to mimic the transfer characteristics of an experimentally verified GaN/AlGaN-based HEMT. As these GaN/AlGaN-based HEMTs are highly susceptible to negative transconductance at lower gate voltages, careful considerations are taken to limit the possibility of obtaining this negative transconductance at lower gate voltages. The study makes use of the 3D conduction band behavior of the AlGaN and GaN layers, the electron concentration and the electric field behavior of the GaN layer to justify the existence of this negative transconductance and alongside validate the legitimacy of the pre-existing theories for the same.