Validation of the sub-circuit modelling approach for substrate resistance in 0.13 μm RF MOSFETs

Great progress has been made on modelling the behaviour of deep-submicron MOS devices, especially concentrating on the performance and operation of the intrinsic device structures. To properly represent the RF performance of these devices, the extrinsic structure must also be considered and a variety of sub-circuit configurations, especially for the substrate, have been proposed. As the frequency of operation rises, it may be expected that more elaborate multi-element substrate sub-circuits will become necessary. Here, we consider the RF operation of advanced 0.13 μm NMOS transistors up to 10 GHz and demonstrate that a simple sub-circuit, using only a single resistor, allows accurate simulation of the two-port parameters, including y ₂₂. We thus demonstrate that the single-resistor substrate sub-circuit approach remains a simple, yet valid, modelling option for MOS simulation up to 10 GHz.