A New Charge-Based Analytical Model for the Gate Current in GaN HEMTs

Abstract

In this article, we present a new charge-based analytical model for the gate current in GaN HEMTs, using an existing model, and modifying it by including the effect of the barrier layer charge, as well as the potentials dropped across the gate–source and gate–drain access regions. Individual models have been presented for the four contributors to the gate current, namely Poole–Frenkel emission (PFE), Fowler–Nordheim tunneling (FNT), thermionic emission (TE), and defect-assisted tunneling (DAT). We have also proposed a new analytical expression for the parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{{0}}$ </tex-math></inline-formula> , appearing in the model for the DAT current. The model results have been compared with the experimental data reported in the literature for both AlGaN/GaN and AlInN/GaN HEMTs over a wide range of gate bias and temperature, and for both zero and nonzero drain–source bias, with the match being found to be excellent, thus validating our model.