Modeling of MOSFET subthreshold swing mismatch with BSIM4 Model

In this paper, we propose a methodology to model the MOSFET subthreshold swing, S mismatch by using BSIM4 model. The 0.18μm CMOS technology silicon data show two trends in the swing mismatch plot. For large-size devices (larger than a critical area AC), the subthreshold swing behaves in a linear trend with smaller slope compared to small-size devices. A mathematical equation as a function of AC is added into the BSIM4 subthreshold swing parameter, nfactor to capture the subthreshold swing mismatch correctly. The mismatch models generated using the proposed methodology shows good agreement with the silicon data and has been tested compatible with HSPICE and SPECTRE simulators.