A Novel Physics-Based Approach to Analyze and Model <i>E</i>-Mode p-GaN Power HEMTs
Nicola Modolo, Shun‐Wei Tang, Hong-Jia Jiang, Carlo De Santi, Matteo Meneghini, Tian‐Li Wu
Abstract
In this article, a physics-based analytical model which considers the channel charge ( Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ch</sub> ) for enhancement-mode p-GaN power high-electron-mobility transistors (HEMTs) is developed. First, by considering the same dynamic channel charge ( dQ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ch</sub> ) for the Schottky/p-GaN junction capacitance ( C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j,Sch</sub> ) and the p-i-n-junction capacitance ( C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p-i-n</sub> ), due to the p-GaN/AlGaN junction and two-dimensional electron gas (2DEG) charge, the analytical formula to calculate the voltage drop in the p-GaN layer ( V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pGaN</sub> ) is presented. Second, by implementing the analytical formulae in the advanced SPICE model (ASM) GaN model, the proposed physics-based model reliably fits the measured C- V and I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> - V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> characteristics of the samples under different processing conditions. This provides significant insight regarding the Mg concentration, the voltage drop at the Schottky metal/p-GaN junction ( V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j,Sch</sub> ), and the voltage drop at the p-GaN/AlGaN junction ( V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p-i-n</sub> ). Finally, the I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> - V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> and I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> - V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub> characteristics of enhancement-mode p-GaN power HEMTs are modeled, displaying good agreement with the experimental data.