A new small signal model parameter extraction method applied to GaN devices

A new parasitic elements extraction method applied to GaN devices is presented. First, using cold S-parameter measurements, high quality starting values for the extrinsic parameters are generated that would place the extraction close to the global minimum of the objective function for the distributed equivalent circuit model. In a second step, the optimal model parameter values are searched through optimization using the starting values already obtained. The validity of the developed method and the proposed small-signal model is verified by comparing the simulated wide-band small-signal S-parameter, over a wide bias range, with measured data of a 0.5 μm GaN HEMT with 2 × 50 μm gate width.