A New Small-Signal Parameter Extraction Technique for Large Gate-Periphery GaN HEMTs

In this letter, we propose a method to extract the small-signal equivalent circuit model for GaN HEMTs using extrinsic-level RF broadband (0.5-50 GHz) Z-parameters. The measured Z-parameters of large gate-periphery GaN devices exhibit certain interesting characteristics, due to their inherently larger intrinsic capacitances and their subsequent interaction with the extrinsic inductances. We exploit these characteristics to simultaneously extract the intrinsic as well as the extrinsic small-signal model components and successfully validate it with measured S-parameter data for a 10 x 90 mu m GaN device.