A simple extraction method for parasitic series resistances in GaN HEMTs considering non-quasi-static effects

A simple technique for extracting the bias-dependent parasitic series resistances of the GaN-based high electron mobility transistor (HEMT) is demonstrated in this paper. With considering the non-quasi-static effect in devices, new analytical Z-parameter formulations are derived to determine parasitic resistances using the curve-fitting algorithm. More accuracy parasitic resistances can be obtained over a wide fitting frequency range compared to the conventional method which ignores the non-quasi-static effect. Here the intrinsic parameters are then calculated directly from intrinsic Y-parameters after de-embedding the parasitic elements in the small-signal equivalent circuit. An excellent agreement between the measured and simulated S-parameters from 100 MHz to 40 GHz is achieved, which validates the feasibility of our method for extracting the bias-dependent parasitic resistances.