Capabilities and limitations of equivalent circuit models for modeling advanced Si FET devices

The most common approaches for modeling semiconductor devices are compact modeling and equivalent circuit based modeling. The former approach has its origin in analogue Si circuits, whereas the latter stems from high-frequency applications using III-V compound devices, such as HEMTs. Due to the increasing RF performance of Si devices, RF modeling engineers have been tailoring equivalent circuit based modeling techniques for Si devices over the past decade. Nevertheless, Si circuit designers continue to prefer compact models. In this paper, we critically evaluate the capabilities and limitations of equivalent circuit based models as applied to Si FET devices. To focus the discussion, the selected device of interest is the advanced FinFET. It is shown that equivalent circuit based models are well suitable for linear and non-linear RF circuit design, but that they are less appropriate for analogue design approaches that rely heavily on flexible scalability.