Empirical modeling of GaN FETs for nonlinear microwave circuit applications

A new approach for the electro-thermal modeling of GaN FETs is presented. The model is identified on-wafer through static I/V curves measured at different base plate temperatures and small-signal parameters. Improvements in the prediction of the dc drain current component under large-signal operation can be obtained by taking into account nonlinear dynamics of charge trapping phenomena. The use of measured pulsed-I/V characteristics is avoided in the model extraction phase. Identification procedures and a wide experimental validation for a 0.25 μm AlGaN/GaN HEMT on SiC with 600 μm periphery are provided in the paper.