Analytical Modeling of Surface-Potential and Intrinsic Charges in AlGaN/GaN HEMT Devices

Abstract

A surface potential (SP)-based analytical model for intrinsic charges in AlGaN/GaN high electron mobility transistor devices is presented. We have developed a precise analytical method to calculate the Fermi-level position <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> from a consistent solution of Schrodinger's and Poisson's equations in the quantum well, considering the two important energy levels. The accuracy of our <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> calculation is on the order of femto-volts for the full range of bias voltage. The SP calculated from <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</sub> is used to derive an analytical model for intrinsic charges in these devices. The model is in excellent agreement with experimental data.