Investigation of Ferroelectric Granularity for Double-Gate Negative-Capacitance FETs Considering Position and Number Fluctuations

摘要

Using TCAD atomistic simulation, this work investigates the ferroelectric layer granularity of double-gate (DG) negative-capacitance FETs (NCFET) by considering both position and number fluctuations. Our study indicates that the impacts of the ferroelectric ratio on threshold voltage (V_T) and subthreshold swing (SS) variations exhibit non-monotonic characteristics, and it is important to include the number fluctuation of the ferroelectric grain to accurately account for the overall variation. In addition, smaller grain size not only reduces the V_T and SS variations, but also improves the mean value of the subthreshold swing.