RF-extraction methods for MOSFET series resistances: A fair comparison

Abstract

Adequate modeling of MOS transistors for RF applications requires the accurate extraction of the extrinsic series resistances. In this paper, we fairly compare several RF extraction methods based on simulation results provided by an accurate foundry compact model of advanced RF MOSFETs. We demonstrate that all published RF characterization methods properly work to extract the extrinsic series resistances when the RF measurement noise is not considered. However, when Vectorial Network Analyzer (VNA) measurement noise on S-parameters is included in the simulations, we clearly conclude that the extracted series resistances are dependent on the extraction procedure. These results demonstrate the high sensitivity of the extracted RF MOSFETs small-signal equivalent circuit with S-parameters measurement noise and therefore the need of specific filtering methods to reduce the VNA noise floor.