In this paper, we present a two-dimensional (2D) analytical modelling of a high electron mobility transistor (HEMT) with ‎a p-layer in the barrier layer. In this model, the channel potential and electric field distributions are derived based on 2D ‎Laplace equation, with Equivalent Potential Method (EPM) and appropriate boundary conditions, and under two ‎assumptions of complete depletion/incomplete depletion. The EPM indicates that charges in the depletion region can be ‎equated to a potential at passivation surface layer. This analytical model shows great simplicity and accuracy. It gives ‎physical insights into the breakdown characteristics of the AlGaN/GaN HEMT with a p-layer in the barrier. This structure ‎reduces the peak electric field at the gate corner near the drain and a new electric field peak is introduced by electric field ‎modulation, which makes the electric field distribution of channel more uniform and, consequently increases the ‎breakdown voltage of the device. The dependence of the channel potential and electric field distributions on length and ‎thickness of the p-layer are investigated. The validity of this model is demonstrated by comparison with the numerical ‎simulations using Silvaco-Atlas device simulator.‎

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