Compact Modeling of GaN HEMTs Switching Transients

S. Faramehr
Swansea University,
United Kingdom

Keywords: GaN, subcircuits, reliability


The demand for reduction in size and increase in switching frequency leads to more power losses in power applications. In particular, GaN-based devices suffer from intrinsic parasitics effecting their efficiency and switching performance. Invoking Angelov model, we develop a methodology for near-real-time modelling of GaN power HEMTs transients including current collapse and pulse switching characteristics. The model, capable of predicting dynamic behaviour of single and multiple power GaN HEMTs at circuit level, is validated against experimental data and TCAD simulations. In experimental tests of fast switching devices such as GaN HEMTs, the switching transients are strongly dependent on the measurement systems. The simulations enable changes to circuit parameters and study of the switching transients. Various compact models have been reported on GaN HEMTs such as physical-based and charged-based models. Developing and run-time of these models can be time-consuming and may lead to convergence issues. There are two approaches in the modeling of current dispersion: (a) analytical and (b) subcircuit. We focus on modelling of switching transients using RC subcircuits. Consequently, we extend existing fast (near-real-time) empirical models to capture nuances of GaN HEMTs. The original contributions of this work are: (a) introducing an approach to evaluate the performance of GaN power HEMTs on the system level, (b) developing a near-real-time empirical compact model, (c) using Simulink integrated with MATLAB as a wide used platform for compact modeling, (d) validating the proposed compact model against pulse measurements and (e) studying double pulse switch transients using RCs.