A learning tool MOSFET model: A stepping-stone from the square-law model to BSIM4

Abstract

Students often experience difficulties grasping the gap between simple square-law MOSFET models and advanced BSIM models with a large number of model parameters for modeling the many second-order short-channel effects (SCE). In this paper, a physics-based learning tool MOSFET model is presented with the aim of serving as a stepping-stone between these two models. The model is based on three model parameters in each of the two regions of strong inversion operation. The three-point model parameter extraction scheme is presented to support student learning and hands-on experience. The model is useful both for small-signal parameter calculations in the analog bias region and for calculation of large-signal currents during logic gate transients. Model accuracy is very good, a lot better than first expected, even if geometry variations have not yet been explored.