Reliable parameter extraction method applied to an enhanced GaN HEMT small-signal model

In this article, a reliable parameter extraction method for GaN HEMT devices is proposed. When the parasitic capacitances are extracted, the judgment condition of the pinch-off voltage is introduced, which avoids the reduction of the reliability of the extracted parasitic capacitances caused by the random selection of the pinch-off voltage. A low gate voltage technology is used to effectively avoid the phenomenon of high forward grid voltage damaging or destroying the Schottky grid. At the same time, due to the influence of hybrid drain parameters (C-d and R-d), the extraction formulas of parasitic resistances and parasitic inductances are deduced in this paper. In order to model the gate leakage current of the device, gate-source resistance (R-gsf) and gate-drain resistance (R-gdf) are introduced and the intrinsic parameter extraction formulas are deduced. The small-signal model for a 1.25-mm GaN HEMT device is established and validated, which show that excellent agreement between measured and modeled S-parameters is obtained in the frequency range of 0.5-20.5 GHz.